- Email: [email protected]
The echocardiographic evaluation of pulmonary atresia with intact ventricular septum
Progress in Pediatric Cardiology 13 Ž2001. 165᎐175
The echocardiographic evaluation of pulmonary atresia with intact ventricular septum Stacey E. DrantU Di¨ ision of Pediatric Cardiology, Room B2-427 MDCC, U.C.L.A. Medical Center, Mattel Children’s Hospital, Uni¨ ersity of California at Los Angeles, 10833 Le Conte A¨ enue, Los Angeles, CA 90095-1743, USA
Abstract Echocardiography has become an integral tool for the diagnosis of pulmonary atresia with intact ventricular septum in both the fetus and the neonate. The echocardiographic assessment has become of paramount importance for decision-making regarding the type of intervention necessary. Patients can be stratified based primarily upon the tricuspid valve Z-score and right ventricular infundibular anatomy into those patients in whom the pulmonary valve can be opened and by which method. Patients with tricuspid valve Z-scores of ) y2.5 have been shown to have almost no risk of having a right ventricular-dependent coronary system and have a high likelihood of achieving a biventricular repair. Those with a patent infundibulum can achieve right ventricular decompression via surgical valvotomy or valvuloplasty in the catheterization lab. Those with a tapering infundibulum generally require an outflow tract patch. Echocardiography is employed after right ventricular decompression to assess: Ž1. the need for an additional shunt; Ž2. adequacy of right ventricular decompression; Ž3. right ventricular growth; and Ž4. assessment of left ventricular function. 䊚 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Pulmonary atresia with intact ventricular septum; Hypoplastic right heart; Tricuspid valve Z-score
1. Diagnosis and pre-operative assessment The diagnosis of pulmonary atresia with intact ventricular septum encompasses a wide spectrum of severity with varying clinical implications. These patients have been divided into two groups: one with hypoplasia of the right ventricular cavity and mural hypertrophy; and the second with a dilated right ventricular cavity and thinning of the right ventricular wall. For purposes of this article, patients with a dilated right ventricle are excluded as they generally do not have suprasystemic right ventricular pressure and pose a different set of clinical problems. For the group with right ventricular hypoplasia, a widely ac-
U
Corresponding author.
cepted working definition includes both patients with complete atresia or pinhole patency of the pulmonary valve along with an intact ventricular septum w1᎐5x. Patients with pinhole patency of the pulmonary valve, in our experience, exhibit the same variability in right ventricular size as do patients with complete atresia and indeed can have right ventricular to coronary artery communications as well. Thus, these patients undergo the same clinical decision-making and are included in the group. The echocardiogram is usually the modality that offers the initial diagnosis after an evaluation for cyanosis in the neonate. Measurements of the tricuspid valve annulus, right ventricular infundibulum, main pulmonary artery and right ventricular volume by echocardiography have been found to correlate well to those made by angiography w3,6,7x. There are many findings on the echocardiogram that are impor-
1058-9813r01r$ - see front matter 䊚 2001 Elsevier Science Ireland Ltd. All rights reserved. PII: S 1 0 5 8 - 9 8 1 3 Ž 0 1 . 0 0 1 0 3 - 5
166
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
tant not only for immediate clinical decision-making but also to assess into which treatment group each patient will likely fall. 1.1. Segmental analysis With rare exception, hearts with pulmonary atresia and intact ventricular septum exhibit levocardia with atrial situs solitus and concordant atrioventricular and ventriculoarterial connections w8x. 1.2. E¨ aluation of the systemic and pulmonary ¨ enous return Anomalies of the venous return are rare in patients with pulmonary atresia and intact ventricular septum. The presence of bilateral superior vena cavae should be evaluated, especially in patients with moderate or severe right ventricular hypoplasia who may require either a Glenn shunt, as part of a partial biventricular repair, or a Fontan procedure. Rare patients may also have interruption of the intrahepatic portion of the inferior vena cava with azygous communication to the superior vena cava. This anomaly is important to note in all patients as its presence may affect all groups. In patients with normal right ventricular size or only mild right ventricular hypoplasia and no significant right ventricular to coronary communications, who may undergo perforation of the valve and valvuloplasty via cardiac catheterization, the choice of vascular access will be affected. In patients in whom a Glenn shunt or Fontan procedure is indicated the presence of an interrupted inferior vena cava has important surgical implications regarding inclusion of the azygous drainage to the pulmonary artery such as in a Kawashima procedure. The pulmonary venous return is usually to the left atrium, however, should be adequately evaluated as any abnormality would be clinically important. 1.3. E¨ aluation of the atrial communication Patients with pulmonary atresia and intact ventricular septum have an obligatory right-to-left shunt that usually occurs through an atrial communication. Usually this is a patent foramen ovale, however, approximately 20% have a true secundum atrial septal defect. Adequacy of this communication is vitally important as these patients are dependent upon it to provide both their systemic and pulmonary blood flow. Obstruction of the atrial communication is uncommon, occurring in approximately 5᎐10% of these patients w8,9x. Because the venous return to the right atrium is a passive process, the gradient generated across the atrial septum with obstruction is often unimpressive. Indirect evidence is often present in-
cluding dilatation of the hepatic veins and inferior vena cava. Doppler interrogation of these systemic veins often reveals accentuated flow reversal in the superior and inferior cavae during atrial contraction or the A wave. These findings are best viewed from the subcostal coronal and sagittal views. 1.4. E¨ aluation of the tricuspid ¨ al¨ e morphology and size Evaluation of the tricuspid valve has become critically important in the evaluation of any patient with pulmonary atresia and intact ventricular septum as the tricuspid valve annulus size has been correlated to right ventricular size w5,7,10x, the presence of right ventricular to coronary communications w11,12x and to the ability of the right ventricle to grow w7,13x. The tricuspid valve morphology in patients with pulmonary atresia and intact ventricular septum is usually abnormal with hypoplasia of the valve annulus, shortening and thickening of the chordae, and myxoid changes of the valve leaflets w8,14,15x. The evaluation of the leaflet excursion is often made difficult by elevation of the right ventricular end diastolic pressures allowing only very brief and limited opening of the valve during atrial systole. The valve is best imaged from the apical view with mild anterior angulation toward the left ventricular outflow tract. The anterior angulation is especially helpful with more severe degrees of hypoplasia. The valve can also be imaged from the subcostal coronal and parasternal views. Measurement of the valve annulus should be taken at the hingepoints of the valve with the valve open ŽFig. 1.. The tricuspid valve annulus Z-score can then be calculated compared to lab normals or can be obtained from a nomogram w16x. The tricuspid valve annulus size and Z-score have been closely correlated to right ventricular size w5,7,10,11,17x as right ventricular volume measurements have been felt by some to be inaccurate by both echocardiography and angiography due to the heavy trabecular patterns. The tricuspid valve annulus size and Z-score have also been closely correlated to the presence of right ventricular to coronary artery communications. Because the presence of important right ventricular to coronary artery communications are the primary impediment to early right ventricular decompression w18x identifying their presence has an impact on the early management. The tricuspid valve can often erroneously be thought to be atretic due to difficulties in imaging the actual opening of the leaflets. In our experience, any patient with pulmonary atresia, intact ventricular septum, and an identifiable right ventricular chamber has a patent tricuspid valve. Those with both tricuspid and pulmonary atresia generally have a slit-like right ven-
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
167
Fig. 1. Apical four chamber view of the tricuspid valve. Cursors mark the measurement of the tricuspid annulus at the hingepoints of the valve. RA, right atrium; LA, left atrium; RV, right ventricle; LV, left ventricle.
tricle that is often difficult to identify. Doppler evaluation of the tricuspid valve can also be helpful in evaluating patency of the tricuspid valve, however, care must be taken to decrease the color velocity scale. With typical velocity color settings very low flow velocities, such as seen across the tricuspid valve, are not displayed. With decreasing of the color scale the tricuspid inflow signals can be visualized by color Doppler primarily during atrial contraction. Tricuspid insufficiency can also be evaluated by color and spectral Doppler. Nearly all patients with pulmonary atresia and intact ventricular septum will have suprasystemic right ventricular pressures and thus the tricuspid insufficiency jet velocities are elevated and can be used to estimate the right ventricular pressure. The degree of tricuspid insufficiency is generally inversely related to the presence of right ventricular to coronary communications. Thus, those patients with little or no tricuspid insufficiency are more likely to have right ventricular to coronary artery communications than those with severe insufficiency w8,14x. Many studies have sought to identify the tricuspid valve annulus size, and hence right ventricular size, that is predictive of the ability to achieve a biventricular repair. In a small patient group McCaffrey et al. w19x evaluated five patients in whom successful right ventricular decompression was accomplished. They concluded that successful outcome, achieving biventricular repair, can be attained in patients whose tricuspid valve diameter was )rs0.75 cm Ž Z-score y2.5 for BSA 0.2 m2 . or the tricuspidrmitral valve
ratio was )rs0.70. The smallest tricuspid valve annulus size in whom a biventricular repair was actually achieved was, however, 0.85 cm. De Leval et al. w13x reviewed data from 51 patients with a small right ventricle who underwent a definitive repair. Among patients in whom a biventricular repair was attempted, survival was highly associated with tricuspid valve size above the lower 99% confidence limit for normal. Bull et al. w20x recalculated the threshold above which deLeval and associates thought biventricular repair could be contemplated, in terms of unadjusted standard deviation units, and produced a guideline of Z ) y2.4. Hanley et al. w11x likewise concluded that the only patient-specific risk factor for not receiving a two-ventricle repair was the Z-value of the tricuspid valve. Giglia et al. w17x reviewed 37 neonates with pulmonary atresia and intact ventricular septum. They found that while right ventricular volume and tricuspid valve diameter were significantly smaller in patients with right ventricular-dependent coronary communications than in those without them, there was no statistically significant association between right ventricular volume or tricuspid valve annulus diameter and survival among patients with or without right ventricular-dependent coronary communications. 1.5. E¨ aluation of right ¨ entricular morphology and size Several studies have documented the ability of even moderate to severely hypoplastic right ventricles to
168
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
grow w3,4,21x and at this end of the spectrum the primary limitation to successful right ventricular decompression appears to be the presence of important right ventricular to coronary artery communications w18,22x. Quantitative assessment of right ventricular volume can be difficult as the myocardial hypertrophy and deep trabeculations make consistency a problem using any technique. Some authors, however, have been able to successfully obtain right ventricular volumes by echocardiography which correlate well to angiographic volumes w3x as well as outcome measured by the ability to achieve biventricular repair w5x. Right ventricular volumes have been measured in the subcostal coronal and sagittal views. The endocardial border at end diastole is measured to include the papillary muscles. The volume is then calculated using biplane Simpson’s rule algorithm w3,5,17x. Alternatively, some have used qualitative assessments of right ventricular size w10,11,23x. Billingsly et al. w23x described surgical management based upon comparison of the right ventricular size, visualized by the right ventricular inflow portion as imaged in the apical view, to that of the left ventricular size. Patients in whom the right ventricular size is at least 2r3 normal size are described as mild hypoplasia, 1r3᎐2r3 normal as moderate hypoplasia, and less than or equal to 1r3 normal as severe hypoplasia. Right ventricular morphology has also been examined. The patency and size of the right ventricular outflow tract appears to have significant importance both in the prediction of right ventricular to coronary artery communications w14x and to the ability for the right ventricle to be successfully decompressed without an outflow patch w22,24x. The right ventricular outflow tract can be best imaged from the subcostal, apical and parasternal views. Adequate imaging from the parasternal views depends upon the size of the right ventricular outflow tract. Division of patients has primarily been based upon ‘patency’ of the right ventricular outflow tract. Patent outflow tracts are those that remain patent up to an atretic membrane which separates it from the main pulmonary artery. The second group termed ‘muscular atresia’ has tapering of the outflow tract that may end blindly proximal to the main pulmonary artery. 1.6. E¨ aluation of the pulmonary ¨ al¨ e, main pulmonary artery and branch pulmonary arteries Like the right ventricular outflow tract, the pulmonary valve and main pulmonary artery can best be imaged from the parasternal views. Care must be taken not to mistake the left atrial appendage for the main pulmonary artery. The valve which is usually completely atretic, however, can have pinhole pa-
tency. The main pulmonary artery and branches are usually well developed due to presence of retrograde flow via the ductus arteriosus w8x, however, there have been cases of absence of the main andror branch pulmonary arteries with pulmonary blood flow supplied through aorticopulmonary collaterals. The main and branch pulmonary arteries are best imaged in the parasternal and high parasternal or suprasternal views. Presence and size of the ductus arteriosus are important for the initial decision-making and adequacy of the dose of prostaglandin. 1.7. E¨ aluation of the coronary circulation and presence of right ¨ entricular to coronary artery communications The ability to identify which patients are likely to have right ventricular to coronary artery communications, and more specifically right ventricular-dependent coronary circulation, has arguably become one of the most important determinants of early management w18x. Imaging of the coronary arteries in patients with pulmonary atresia with intact septum has improved significantly with improved imaging technology. The coronary ostia can be identified along with the major branches of the coronary arteries, however, coronary angiography remains necessary to completely evaluate patients for the location and size of fistulous communications and more distal coronary stenoses. Because the right ventricular to coronary artery communications occur primarily to the right coronary and left anterior descending coronary vessels these should be imaged in the parasternal long and short axis views. In patients with patent coronary ostia and right ventricular communications to the coronary artery, spectral Doppler will reveal antegrade flow into the coronary artery during diastole with systolic flow reversal ŽFig. 2.. In certain patients with large fistulae, the coronary artery with the fistula may become quite dilated ŽFig. 3.. In patients with complete ostial atresia or significant proximal stenosis, only retrograde flow during systole is visualized distal to the obstruction due to filling primarily from the right ventricle. Often imaging of the right ventricular apex with color Doppler will identify fistula which are often present at the right ventricular apex. Markers such as the tricuspid valve annulus size and Z-score have been quite useful in identifying those patients at highest risk for the presence of right ventricular to coronary artery communications w12x. In addition, in our laboratory, we have found the diameter of the right ventricular infundibulum to be an accurate predictor as well. Both the tricuspid valve annulus size and Z-score and the morphology of the right ventricular outflow tract have shown strong correlation to the presence of right ventricular to coronary artery communications, however, neither of these
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
169
Fig. 2. Spectral Doppler interrogation of a coronary artery in a patient with right ventricular to coronary artery communications. There is to and fro flow within the coronary artery with retrograde flow in the coronary artery during systole Žrepresented below the baseline . and antegrade flow during diastole Žrepresented above the baseline ..
markers has been able to distinguish those patients with right ventricular-dependent coronary circulation. Satou et al. w12x compared the tricuspid valve Z-scores of 30 patients with pulmonary atresia and intact ventricular septum to their coronary artery pathology by angiography. The coronary artery pathology was
graded as: 0 s no fistulae; 1 s fistulaerno right ventricular-dependent coronary arteries; 2 s fistulae with one right ventricular-dependent coronary; 3 s fistulae with )rs2 right ventricular-dependent coronary arteries. While all patients with a tricuspid valve Z-score of ᎐2.0 had coronary fistulae, none of those with
Fig. 3. Parasternal short axis image of a dilated right coronary artery Žcourse indicated by the arrows. in a patient with large right ventricular to coronary artery communications.
170
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
significant coronary artery pathology Žgrade 2 or 3 coronary pathology. had Z-scores of ) y2.5. 1.8. E¨ aluation of the mitral ¨ al¨ e and left ¨ entricle
The mitral valve is usually normal in these patients, however, they can have isolated abnormalities such as clefts or double orifice valves w8x. Left ventricular function and regional wall motion abnormalities should be carefully assessed as it has been shown that these patients can have left ventricular wall motion abnormalities both due to ischemia and independently to effects of elevated right ventricular filling pressure w25᎐30x. Myocardial ischemia and infarction have been described to occur prenatally w31x. The wall motion of the interventricular septum is usually abnormal prior to intervention due to the suprasystemic right ventricular pressure. There can be bulging of the interventricular septum into the left ventricular outflow tract, however, significant left ventricular outflow tract obstruction has not been described. The left ventricular wall motion is best assessed in the apical view and parasternal views. Akagi et al. w25x reviewed 21 patients by cardiac catheterization to assess the influence of right ventricular to coronary artery communications on left ventricular performance. They found left ventricular wall motion abnormalities in eight patients, seven of which had coronary artery abnormalities. Those with wall motion abnormalities also had significantly lower ejection fraction Ž50 " 6 vs. 57 " 7%. and significantly higher right-to-left ventricular systolic pressure ratio Ž1.46" 0.16 vs. 0.8" 0.45. than in those with normal wall motion. During the follow-up five patients, all with abnormal wall motion, died. Gentles et al. w26x evaluated the effect of right ventricular decompression on left ventricular function in patients with less extensive coronary artery abnormalities Žfistula alone or with one coronary artery stenosis.. They analyzed pre-operative and post-operative echocardiograms for global and regional left ventricular function in 24 patients. There was no significant difference in the global left ventricular function between those with and without coronary artery abnormalities before or after right ventricular decompression. After right ventricular decompression three patients developed depressed left ventricular ejection fractions, all of whom had regional wall motion abnormalities and coronary artery abnormalities. In those with coronary artery abnormalities regional dysfunction occurred in areas supplied by abnormally connected or stenosed coronary arteries. Regional left ventricular dysfunction was rare in patients without coronary artery abnormalities.
1.9. E¨ aluation of the aortic ¨ al¨ e and aortic arch The aortic valve and aortic arch are usually normal, however, there have been rare patients with associated valvar aortic stenosis w8x. This has been encountered rarely in our institution as well and these patients have a high mortality. We have not encountered any patients with aortic arch anomalies. The aortic valve can be imaged in the subcostal coronal, apical, and parasternal long axis views to evaluate for doming of the valve leaflets and to obtain gradients by Doppler evaluation. The cuspal morphology can best be viewed from the parasternal short axis view.
2. Post procedure evaluation In general, patients will fall into two categories of management based in large part upon the coronary artery circulation and the patency of the right ventricular outflow tract. This will distinguish patients in whom right ventricular decompression is deemed unsafe and will usually involve placement of a systemic to pulmonary shunt alone vs. patients in whom decompression of the right ventricle is attempted. Currently, the second group may have right ventricular decompression performed in the cardiac catheterization laboratory with perforation of the valve if necessary followed by pulmonary valvuloplasty or surgical intervention via either a valvotomy andror right ventricular outflow tract patch. In addition, some of the patients in whom right ventricular decompression is performed may require an additional source of pulmonary blood flow in the form of a systemic to pulmonary artery shunt. 2.1. E¨ aluation status post placement of systemic to pulmonary artery shunt As stated above, patients in whom a systemic to pulmonary artery shunt is performed without decompression of the right ventricle tend to have significant coronary artery pathology and are felt to have a coronary circulation whose perfusion is dependent upon preservation of right ventricular hypertension. In this group of patients the long-term follow-up generally focuses upon patency of the shunt and left ventricular function with an emphasis upon segmental wall motion. The left ventricular function should be followed closely due to the risk for development of coronary stenoses or occlusion due to intimal proliferation at the sites of right ventricular to coronary fistulae w32᎐34x. Without decompression establishing
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
flow through the right ventricle, the right ventricle and tricuspid valve do not grow in proportion to the somatic growth of the patient and thus become relatively smaller as the patient grows. 2.2. E¨ aluation status post right ¨ entricular decompression Decompression of the right ventricle can take many forms including perforation of the valve and valvuloplasty during cardiac catheterization, surgical valvotomy, and placement of a right ventricular outflow tract patch. In general, the follow-up regardless of the approach involves: Ž1. early evaluation assessing the need for an additional shunt; Ž2. adequacy of decompression and right ventricular pressure; Ž3. assessment of growth of the right ventricle and tricuspid valve; and Ž4. assessment of left ventricular function. 2.3. E¨ aluating the need for an additional shunt Several studies have addressed management of neonates after surgical valvotomy w7,11,13,19᎐ 21,35᎐38x and it has become clear that the combination of elevated pulmonary vascular resistance and poor right ventricular compliance in the early postoperative period combine to limit pulmonary blood flow such that shunts are often placed at the time of right ventricular decompression. The use of prolonged prostaglandin therapy after pulmonary valvotomy has been shown to bridge many patients through this period avoiding placement of a subsequent shunt w19,35,36x. Trowitzsch et al. w5x reported on echocardiographic predictors for those patients in whom an additional shunt will be required. They reviewed 15 patients with either critical pulmonary stenosis or pulmonary atresia and intact ventricular septum and compared the normalized right ventricular end diastolic volume ŽRVEDV., tricuspid valve annulus diameter, wall thickness, area change fraction and ejection fraction in those patients who required an additional shunt vs. those that did not. In the group of patients with RVEDV - 5.0 mlrm2 the shunt was performed as part of the initial procedure thus making the requirement for the shunt uncertain. They found that relief of right ventricular outflow tract obstruction alone provided adequate palliation in all patients with normalized right ventricular end diastolic volume of ) 11 mlrm2 . In those with normalized RVEDV - 5 mlrm2 or tricuspid valve annulus dimension of - 1 cmrm 2r3 all required a shunt. In the intermediate group Žnormalized RVEDV between 5.0 and 11 mlrm2 ., all with a normalized RVEDV - 6.0 mlrm2 or a tricuspid valve diameter of - 1.4 cmrm 2r3 required a subsequent shunt while those with an RVEDV )rs6.0 mlrm2 and tricuspid di-
171
ameter of )rs1.4 cmrm 2r3 did not require an additional shunt. Wall thickness, area change fraction and ejection fraction measurements did not significantly correlate with right ventricular volume or post-operative outcome. They concluded that if either the ventricular volume or tricuspid annulus size is excessively small, a shunt procedure is necessary. Steinberger et al. w36x reviewed 15 patients in whom a right ventricular outflow tract patch was performed as the initial surgery during the neonatal period without an additional shunt. The patients were maintained on prostaglandin post-operatively and criteria for weaning prostaglandin was based on Doppler assessment of increasing antegrade tricuspid flow and clinical evidence of satisfactory pulmonary blood flow. Only 1 of 15 subsequently required a shunt and 11 of these had measurements of the tricuspid valve diameter. The tricuspid valve diameters ranged from 7 to 12 mm in patients not requiring a subsequent shunt and was 8 mm in the patient that required a shunt. Right ventricular volume measurements were available for 14 patients and ranged from 2.7 to 48 mlrm2 in those not requiring a shunt and was 3.5 mlrm2 in the patient that subsequently required a shunt. They concluded that early placement of a right ventricular outflow patch regardless of right ventricular anatomy results in good long-term palliation with an excellent chance for biventricular repair. 2.4. Adequacy of right ¨ entricular decompression and estimation of right ¨ entricular pressure The approach to right ventricular decompression is made primarily upon establishing patency of the right ventricular outflow tract and pulmonary valve. In patients with membranous atresia and a widely patent outflow tract, either perforation and valvuloplasty during cardiac catheterization or surgical valvotomy can adequately relieve the obstruction whereas those patients with tapering or hypoplastic outflow tracts often require a right ventricular outflow patch. Evaluation of the adequacy of right ventricular decompression after these procedures is vitally important as subsequent growth of the right ventricle depends upon resolution of the hypertrophy and improvement of right ventricular compliance w20x. By two-dimensional imaging the right ventricular outflow tract and pulmonary valve can be imaged from subcostal, apical and parasternal views. The right ventricular outflow tract is examined for the presence of dynamic narrowing with systole that can often occur once the afterload is acutely reduced. The valve should be assessed for annulus size and visualization of the orifice. By color Doppler, the flow across the outflow tract and valve can be further assessed for turbulence and narrowing of the jet. The severity of residual stenosis can be
172
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
quantified by measuring the peak and mean gradients across the pulmonary valve. If significant subvalvar obstruction is present the modified Bernoulli equation should be used. Any dynamic right ventricular outflow tract obstruction will often have the characteristic late peaking flow profile which distinguishes it from residual fixed obstruction at the level of the valve annulus. Measuring the right ventricular pressure provides an indirect estimate of residual obstruction to right ventricular outflow. The right ventricular pressure can be quantitated directly by measuring the peak gradient of the tricuspid valve insufficiency jet. One must assume both the right atrial pressure and the pulmonary artery pressure to calculate the degree of residual right ventricular outflow tract obstruction. The latter estimate can be inaccurate in the presence of a ductus arteriosus, systemic to pulmonary artery shunt, and during the neonatal period as the pulmonary vascular resistance remains variably elevated. Observing the curvature of the interventricular septum during systole can be useful as a qualitative estimate of differentiating right ventricular pressure as subsystemic, systemic, or suprasystemic. Indirect evidence of adequacy of right ventricular decompression includes patterns of diastolic filling. Findings of a large A wave opening on the pulmonary artery Doppler is an indicator of a stiff, non-compliant right ventricle w39x. 2.5. Assessment of growth of the tricuspid ¨ al¨ e and right
¨ entricle
Most early studies aimed at measuring tricuspid valve and right ventricular growth utilized angiographic measurements w7,13,21,35,37,38x, however, more recent studies have provided echocardiographic assessment w3,4,17,20,36x. Schmidt et al. w3x evaluated the early changes in right ventricular volume, area ratio and stroke volume before and at an average of 5 days and 19 days after pulmonary valvotomy. All patients except one had right ventricular hypoplasia before valvotomy. They found that at 5 days after valvotomy the RVEDV decreased from 16.6" 6.4 to 10.6" 4.6 mlrm2 and the stroke volume decreased from 8.3" 3.5 to 5.5" 2.8 mlrm2 . The right ventricular area ratio also decreased from 0.56" 0.09 to 0.39" 0.08. By the second evaluation at 19 days post-valvotomy the RVEDV had reached the preoperative size of 18 " 6.2 mlrm2 as had the right to left ventricular area ratio 0.55" 0.08. Importantly, the right ventricular stroke volume had increased to 10.4" 3.9 mlrm2 from 8.3" 3.5 mlrm2 . Their echocardiographic measures of RVEDV and stroke volume correlated closely with angiographic measurements. They concluded that right ventricular
volumes can be accurately measured by echocardiography and that because of the early decrease in right ventricular size after decompression an additional source of pulmonary blood flow may be necessary to support these neonates and may aid in determining timing for weaning of prostaglandin. Hanseus et al. w4x evaluated right ventricular growth in 10 patients with critical pulmonary stenosis or pulmonary atresia and intact septum that survived right ventricular decompression. They utilized measurement of the right ventricular cross-sectional area obtained from the ventricular length and width in the apical or subcostal four chamber views. This was expressed in standard deviation from the normal mean based on body surface area. They concluded that in all seven patients with a normal right ventricle at follow-up, right ventricular to pulmonary artery communication had been established in the neonatal period. The three patients in whom right ventricular growth into the normal range was not achieved had absent or ineffective flow through the right ventricle during the first months of life. Steinberger et al. w36x evaluated tricuspid valve and right ventricular growth in 15 survivors of neonatal right ventricular outflow tract patch placement. They were divided into two groups based on right ventricular morphology with group 1 composed of tripartite right ventricle and group 2 with unipartite or bipartite ventricular morphology. Average follow-up was 5.8 years Žrange 1.5᎐11 years.. In group 1, mean right ventricular volume increased from 23.6" 3.7 to 50.7 " 7.7 mlrm2 . In group 2, mean right ventricular volume increased from 5.2" 1.1 to 38.5" 7.7 mlrm2 . There was a comparative increase in tricuspid valve annulus size from 11.7" 1.4 to 23.5" 2.2 mm in group 1 and from 9.2" 0.8 to 21 " 3 mm in group 2. Twelve of these 15 survivors had biventricular physiology while three were awaiting evaluation for biventricular repair. 2.6. Assessment of left ¨ entricular function Post-operative assessment of left ventricular function is important particularly in two instances. First, those patients in whom right ventricular to coronary artery communications are present prior to right ventricular decompression. These patients can develop left ventricular dysfunction early after decompression due to dependence of the coronary circulation on right ventricular hypertension or later due to progressive intimal hyperplasia within the coronary artery resulting in late stenosis or occlusion w32᎐34x. Second, in patients in whom right ventricular decompression was unsuccessful with abnormal septal motion.
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
3. Prenatal diagnosis of pulmonary atresia with intact ventricular septum Fetal echocardiography became established as a reliable tool for prenatal diagnosis of congenital heart disease in the early 1980s. The spectrum of congenital heart disease diagnosed prenatally is skewed to more severe forms of malformations. Because of this, the incidence of pulmonary atresia with intact ventricular septum diagnosed in utero tends to be higher than in the live born population. Early in their experience Allan et al. w39x described that five of seven cases diagnosed prenatally had severe tricuspid insufficiency and dilated right ventricles whereas only two of seven had right ventricular hypoplasia. However, later in their experience w40x this ratio has reversed. The form of pulmonary atresia with intact ventricular septum and right ventricular hypoplasia is less obvious requiring a higher degree of expertise of the sonographer. They attributed this shift in pattern of prenatal diagnosis to increasing expertise in general obstetric scanning as the majority of cases were referred because of suspicion of an abnormality on routine obstetric screening ultrasound. In the form of pulmonary atresia with intact septum with right ventricular hypoplasia the cardiothoracic ratio is usually within the normal range. As in postnatal patients, there are varying degrees of right ventricular size ranging from nearly normal in size to severely hypoplastic. The right ventricular walls are nearly always hypertrophied and endocardial fibroelastosis may be present with increased echogenicity of the endocardium. The right ventricular wall motion is often decreased reflecting the increased afterload caused by the atretic pulmonary valve. The tricuspid valve annulus is often hypoplastic and the tricuspid valve leaflet motion is usually diminished. One should carefully inspect the motion of both the tricuspid and pulmonary valves for motion using two-dimensional imaging from multiple planes if possible. The left heart structures are usually normal, however, there have been cases of associated valvar aortic stenosis. By color Doppler, the right ventricular outflow tract and pulmonary valve should be interrogated for any antegrade flow across them. The ductus arteriosus should also be interrogated for reverse flow, however, this has not been reliable in distinguishing stenosis from atresia w42x. One of the difficult aspects of fetal diagnosis that has been well established is the prenatal progression of the severity of some defects w41᎐48x. In general, the heart is formed by 7᎐8 weeks gestation, however, there are now multiple reports of progression of pulmonary valve stenosis to atresia between an initial echocardiogram at 18᎐20 weeks gestation and birth. Because the fetal circulation is in parallel rather than in series,
173
the flow through the right ventricle can vary which decreases the reliability of increased flow velocities across the pulmonary valve. This places increased emphasis on careful inspection of the thickness and motion of the pulmonary valve by two-dimensional imaging and attention to the relative right vs. left heart chamber sizes. Once flow ceases through the right ventricle its growth also fails to keep pace with the rest of the heart and this discrepancy in chamber sizes becomes more apparent. Thus, any patients with a diagnosis of pulmonary stenosis or atresia with intact ventricular septum should be counseled regarding the chances of progression and monitored closely throughout pregnancy. Daubeney et al. w49x have published their experience of prenatal diagnosis in the United Kingdom. They found a decrease in the incidence of pulmonary atresia and intact ventricular septum diagnosed after birth and attributed this to the fact that many of their patients choose to interrupt the pregnancy. Prenatal intervention has been attempted sporadically, however, many have been unsuccessful for technical problems. Unfortunately, of the valves that have been opened, most have again become stenosed prior to birth.
4. Conclusions Many studies mentioned here appear to direct us to similar conclusions. First that patients with a tricuspid valve Z-score of )rsy2.5 are at very low risk for having right ventricular-dependent coronary circulation and a very high likelihood of achieving a biventricular repair provided they achieve successful right ventricular decompression early in life. Right ventricular decompression can be successfully performed by either valvuloplasty in the catheterization lab or by surgical valvotomy in those patients with a patent infundibulum, however, those patients with a tapering or hypoplastic infundibulum this may require placement of an outflow patch. References w1x Bonnet D, Gautier-Lhermitte I, Bonhoeffer P, Sidi D. Right ventricular myocardial sinusoidal᎐coronary artery connections in critical pulmonary valve stenosis. Pediatr Cardiol 1998;19:269᎐271. w2x Weldon CS, Hartmann AF, McKnight RC. Surgical management of hypoplastic right ventricle with pulmonary atresia or critical pulmonary stenosis and intact ventricular septum. Ann Thorac Surg 1984;37Ž1.:12᎐22. w3x Schmidt KG, Cloez JL, Silverman NH. Changes of right ventricular size and function in neonates after valvotomy for pulmonary atresia or critical pulmonary stenosis and intact ventricular septum. J Am Coll Cardiol 1992;19Ž5.:1032᎐1037. w4x Hanseus K, Bjorkhem G, Lundstrom NR, Laurin S. Crosssectional echocardiographic measurements of right ventricu-
174
w5x
w6x w7x w8x
w9x w10x w11x
w12x
w13x w14x w15x w16x w17x w18x
w19x w20x
w21x w22x
w23x
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175 lar size and growth in patients with pulmonary atresia and intact ventricular septum. Pediatr Cardiol 1991;12:135᎐142. Trowitzsch E, Colan SD, Sanders SP. Two-dimensional echocardiographic evaluation of right ventricular size and function in newborns with severe right ventricular outflow tract obstruction. J Am Coll Cardiol 1985;6:388᎐393. Leung MP, Mok CK, Hui PW. Echocardiographic assessment of neonates with pulmonary atresia and intact ventricular septum. J Am Coll Cardiol 1988;12:719᎐725. Patel RG, Freedom RM, Moes CAF et al. Right ventricular volume determinations in 18 patients with pulmonary atresia and intact ventricular septum. Circulation 1980;61Ž2.:428᎐440. Freedom RM, Wilson G, Trusler GA, Williams WG, Rowe RD. Pulmonary atresia and intact ventricular septum: a review of the anatomy, myocardium, and factors influencing right ventricular growth and guidelines for surgical intervention. Scand J Thor Cardiovasc Surg 1982;17:1᎐28. Freedom RM. The morphologic variations of pulmonary atresia with intact ventricular septum: guidelines for surgical intervention. Ped Cardiol 1983;4:183᎐188. Bull C, deLeval MR, Mercanti C, Macartney FJ, Anderson RH. Pulmonary atresia and intact ventricular septum: a revised classification. Circulation 1982;66Ž2.:266᎐271. Hanley FL, Sade RM, Blackstone EH, Kirklin JW, Freedom RM, Nanda NC. Outcomes in neonatal pulmonary atresia with intact ventricular septum. A multiinstitutional study. J Thorac Cardiovasc Surg 1993;105:406᎐427. Satou GM, Perry SB, Gauvreau K, Geva T. Echocardiographic predictors of coronary artery pathology in pulmonary atresia with intact ventricular septum. Am J Cardiol 2000; 85:1319᎐1324. De Leval M., Bull C., Hopkins R. et al. Decision making in the definitive repair of the heart with a small right ventricle. Circulation 1985; 72 Suppl II: II52᎐II60. Anderson RH, Anderson C, Zuberbuhler JR. Further morphologic studies on hearts with pulmonary atresia and intact ventricular septum. Cardiol Young 1991;1:105᎐113. Choi YH, Seo JW, Choi JY, Yun YS, Kim SH, Lee HJ. Morphology of tricuspid valve in pulmonary atresia with intact ventricular septum. Pediatr Cardiol 1998;19:189᎐381. Kirklin JW, Barratt-Boyes BG. Cardiac surgery. 2nd ed., chap 1 New York: Churchill Livingstone, 1992. Giglia TM, Jenkins KJ, Matitiau A et al. Influence of right heart size on outcome in pulmonary atresia with inact ventricular septum. Circulation 1993;88Žpart 1.:2248᎐2256. Giglia TM, Mandell VS, Connor AR, Mayer JE, Lock JE. Diagnosis and management of right ventricle-dependent coronary circulation in pulmonary atresia with intact ventricular septum. Circulation 1992;86:1516᎐1528. McCaffrey FM, Leatherbury L, Moore HV. Pulmonary atresia and intact ventricular septum. Definitive repair in the neonatal period. J Thorac Cardiovasc Surg 1991;102:617᎐623. Bull C, Kostelka M, Sorensen K, de Leval M. Outcome measures for the neonatal management of pulmonary atresia with intact ventricular septum. J Thorac Cardiovasc Surg 1994;107:359᎐366. Lewis AB, Wells W, Lindesmith GG. Right ventricular growth potential in neonates with pulmonary atresia and intact ventricular septum. J Thorac Cardiovasc Surg 1986;91:835᎐840. Mainwaring RD, Lamberti JJ. Pulmonary atresia with intact ventricular septum ᎏ surgical approach based on ventricular size and coronary anatomy. J Thorac Cardiovasc Surg 1993;106:733᎐738. Billingsly AM, Laks H, Boyce SW, George B, Santulli T, Williams RG. Definitive repair in patients with pulmonary atresia and intact ventricular septum. J Thorac Cardiovasc Surg 1989;97:746᎐754.
w24x Pawade A, Capuani A, Penny DJ, Karl TR, Mee RBB. Pulmonary atresia with intact ventricular septum: surgical management based on right ventricular infundibulum. J Card Surg 1993;8:371᎐383. w25x Akagi T, Benson LN, Williams WG et al. Ventriculo-coronary arterial connections in pulmonary atresia with intact ventricular septum, and their influences on ventricular performance and clinical course. Am J Cardiol 1993;72:586᎐590. w26x Gentles TL, Colan SD, Giglia TM, Mandell VS, Mayer JE, Sanders SP. Right ventricular decompression and left ventricular function in pulmonary atresia with intact ventricular septum: the influence of less extensive coronary anomalies. Circulation 1993;88Žpart 2.:183᎐188. w27x Sideris EB, Olley PM, Spooner E et al. Left ventricular function and compliance in pulmonary atresia with intact ventricular septum. J Thorac Cardiovasc Surg 1982;84: 192᎐199. w28x Freedom RM, Harrington DP. Contributions of intramyocardial sinusoids in pulmonary atresia and intact ventricular septum to a right-sided circular shunt. Br Heart J 1974; 36:1061᎐1065. w29x Taylor RR, Covell JW, Sonnenblick EH, Ross J. Dependence of ventricular distensibility on filling of the opposite ventricle. Am J Physiol 1967;213Ž3.:711᎐718. w30x Bemis CE, Serur JR, Borkenhagen D, Sonnenblick EH, Urschel CW. Influence of right ventricular filling pressure on left ventricular pressure and dimension. Circ Res 1974;34: 498᎐504. w31x Koike K, Perrin D, Wilson GJ, Freedom RM. Myocardial ischemia and coronary arterial involvement in newborn babies less than one week old with pulmonary atresia and intact ventricular septum. In: Freedom RM, editor. Pulmonary atresia with intact ventricular septum. Mount Kisco, NY: Futura Publishing Company, Inc., 1989:101᎐107. w32x Fyfe DA, Edwards WD, Driscoll DJ. Myocardial ischemia in patients with pulmonary atresia and intact ventricular septum. J Am Coll Cardiol 1986;8:402᎐406. w33x Wilson GJ, Freedom RM, Koike K, Perrin D. The coronary arteries: anatomy and histopathology. Pulmonary atresia with intact ventricular septum. Mount Kisco, NY: Futura Publishing Company, Inc., 1989 75᎐88. w34x Gittenberger-de Groot AC, Sauer U, Bindl L, Babic R, Essed CE, Buhlmeyer K. Competition of coronary arteries and ventriculo-coronary arterial communications in pulmonary atresia with intact ventricular septum. Int J Cardiol 1988; 18:243᎐258. w35x Foker Je, Braunlin EA, Cyr St. JA et al. Management of pulmonary atresia with intact ventricular septum. J Thorac Cardiovasc Surg 1986;92:706᎐715. w36x Steinberger J, Berry JM, Bass JL et al. Results of a right ventricular outflow patch for pulmonary atresia with intact ventricular septum. Circulation 1992;86ŽSuppl II.:II167᎐II175. w37x Amodeo A, Keeton BR, Sutherland GR, Monro JL. Pulmonary atresia with intact ventricular septum: is neonatal repair advisable? Eur J Cardio-thorac Surg 1991;5:17᎐21. w38x Shaddy RE, Sturtevant Je, Judd VE, McGough EC. Right ventricular growth after transventricular pulmonary valvotomy and central aortopulmonary shunt for pulmonary atresia and intact ventricular septum. Circulation 1990;82ŽSuppl IV.:IV157᎐IV163. w39x Snider RA, Serwer GA, Ritter SB. Echocardiography in pediatric heart disease. 2nd ed. St. Louis, MO: Mosby, 1997. Chapter 5 w40x Allan LD, Crawford DC, Tynan MJ. Pulmonary atresia in prenatal life. J Am Coll Cardiol 1986;8:1131᎐1136. w41x Allan LD, Cook A. Pulmonary atresia with intact ventricular septum in the fetus. Cardiol Young 1992;2:367᎐376.
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175 w42x Hornberger LK, Benacerraf BR, Bromley BS, Spevak PJ, Sanders SP. Prenatal detection of severe right ventricular outflow tract obstruction: pulmonary stenosis and pulmonary atresia. J Ultrasound Med 1994;13:743᎐750. w43x Allan LD. Development of congenital lesions in mid or late gestation. Int J Cardiol 1988;19:361᎐362. w44x Hornberger LK, Sanders SP, Sahn DJ et al. In utero pulmonary artery and aortic growth and potential for progression of pulmonary outflow tract obstruction in tetralogy of fallot. J Am Coll Cardiol 1995;25:739᎐745. w45x Hornberger LK, Sanders SP, Azaria JJT et al. Left heart obstructive lesions and left ventricular growth in the midtrimester fetus. Circulation 1995;92:1531᎐1538.
175
w46x Rice MJ, McDonald RW, Reller MD. Progressive pulmonary stenosis in the fetus: two case reports. Am J Perinatol 1993;10Ž6.:424᎐427. w47x Guntheroth WG, Cyr DR, Winter T, Easterling T, Mack LA. Fetal Doppler echocardiography in pulmonary atresia. J Ultrasound Med 1993;5:281᎐284. w48x Allan LD, Sharland G, Tynan MJ. The natural history of the hypoplastic left heart syndrome. Int J Cardiol 1989; 25:341᎐343. w49x Daubeney PEF, Sharland GK, Cook AC, Keeton BR, Anderson RH, Webber SA. Pulmonary atresia with intact ventricular septum: impact of fetal echocardiography on incidence at birth and postnatal outcome. Circulation 1998;98:562᎐566.
The echocardiographic evaluation of pulmonary atresia with intact ventricular septum Stacey E. DrantU Di¨ ision of Pediatric Cardiology, Room B2-427 MDCC, U.C.L.A. Medical Center, Mattel Children’s Hospital, Uni¨ ersity of California at Los Angeles, 10833 Le Conte A¨ enue, Los Angeles, CA 90095-1743, USA
Abstract Echocardiography has become an integral tool for the diagnosis of pulmonary atresia with intact ventricular septum in both the fetus and the neonate. The echocardiographic assessment has become of paramount importance for decision-making regarding the type of intervention necessary. Patients can be stratified based primarily upon the tricuspid valve Z-score and right ventricular infundibular anatomy into those patients in whom the pulmonary valve can be opened and by which method. Patients with tricuspid valve Z-scores of ) y2.5 have been shown to have almost no risk of having a right ventricular-dependent coronary system and have a high likelihood of achieving a biventricular repair. Those with a patent infundibulum can achieve right ventricular decompression via surgical valvotomy or valvuloplasty in the catheterization lab. Those with a tapering infundibulum generally require an outflow tract patch. Echocardiography is employed after right ventricular decompression to assess: Ž1. the need for an additional shunt; Ž2. adequacy of right ventricular decompression; Ž3. right ventricular growth; and Ž4. assessment of left ventricular function. 䊚 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Pulmonary atresia with intact ventricular septum; Hypoplastic right heart; Tricuspid valve Z-score
1. Diagnosis and pre-operative assessment The diagnosis of pulmonary atresia with intact ventricular septum encompasses a wide spectrum of severity with varying clinical implications. These patients have been divided into two groups: one with hypoplasia of the right ventricular cavity and mural hypertrophy; and the second with a dilated right ventricular cavity and thinning of the right ventricular wall. For purposes of this article, patients with a dilated right ventricle are excluded as they generally do not have suprasystemic right ventricular pressure and pose a different set of clinical problems. For the group with right ventricular hypoplasia, a widely ac-
U
Corresponding author.
cepted working definition includes both patients with complete atresia or pinhole patency of the pulmonary valve along with an intact ventricular septum w1᎐5x. Patients with pinhole patency of the pulmonary valve, in our experience, exhibit the same variability in right ventricular size as do patients with complete atresia and indeed can have right ventricular to coronary artery communications as well. Thus, these patients undergo the same clinical decision-making and are included in the group. The echocardiogram is usually the modality that offers the initial diagnosis after an evaluation for cyanosis in the neonate. Measurements of the tricuspid valve annulus, right ventricular infundibulum, main pulmonary artery and right ventricular volume by echocardiography have been found to correlate well to those made by angiography w3,6,7x. There are many findings on the echocardiogram that are impor-
1058-9813r01r$ - see front matter 䊚 2001 Elsevier Science Ireland Ltd. All rights reserved. PII: S 1 0 5 8 - 9 8 1 3 Ž 0 1 . 0 0 1 0 3 - 5
166
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
tant not only for immediate clinical decision-making but also to assess into which treatment group each patient will likely fall. 1.1. Segmental analysis With rare exception, hearts with pulmonary atresia and intact ventricular septum exhibit levocardia with atrial situs solitus and concordant atrioventricular and ventriculoarterial connections w8x. 1.2. E¨ aluation of the systemic and pulmonary ¨ enous return Anomalies of the venous return are rare in patients with pulmonary atresia and intact ventricular septum. The presence of bilateral superior vena cavae should be evaluated, especially in patients with moderate or severe right ventricular hypoplasia who may require either a Glenn shunt, as part of a partial biventricular repair, or a Fontan procedure. Rare patients may also have interruption of the intrahepatic portion of the inferior vena cava with azygous communication to the superior vena cava. This anomaly is important to note in all patients as its presence may affect all groups. In patients with normal right ventricular size or only mild right ventricular hypoplasia and no significant right ventricular to coronary communications, who may undergo perforation of the valve and valvuloplasty via cardiac catheterization, the choice of vascular access will be affected. In patients in whom a Glenn shunt or Fontan procedure is indicated the presence of an interrupted inferior vena cava has important surgical implications regarding inclusion of the azygous drainage to the pulmonary artery such as in a Kawashima procedure. The pulmonary venous return is usually to the left atrium, however, should be adequately evaluated as any abnormality would be clinically important. 1.3. E¨ aluation of the atrial communication Patients with pulmonary atresia and intact ventricular septum have an obligatory right-to-left shunt that usually occurs through an atrial communication. Usually this is a patent foramen ovale, however, approximately 20% have a true secundum atrial septal defect. Adequacy of this communication is vitally important as these patients are dependent upon it to provide both their systemic and pulmonary blood flow. Obstruction of the atrial communication is uncommon, occurring in approximately 5᎐10% of these patients w8,9x. Because the venous return to the right atrium is a passive process, the gradient generated across the atrial septum with obstruction is often unimpressive. Indirect evidence is often present in-
cluding dilatation of the hepatic veins and inferior vena cava. Doppler interrogation of these systemic veins often reveals accentuated flow reversal in the superior and inferior cavae during atrial contraction or the A wave. These findings are best viewed from the subcostal coronal and sagittal views. 1.4. E¨ aluation of the tricuspid ¨ al¨ e morphology and size Evaluation of the tricuspid valve has become critically important in the evaluation of any patient with pulmonary atresia and intact ventricular septum as the tricuspid valve annulus size has been correlated to right ventricular size w5,7,10x, the presence of right ventricular to coronary communications w11,12x and to the ability of the right ventricle to grow w7,13x. The tricuspid valve morphology in patients with pulmonary atresia and intact ventricular septum is usually abnormal with hypoplasia of the valve annulus, shortening and thickening of the chordae, and myxoid changes of the valve leaflets w8,14,15x. The evaluation of the leaflet excursion is often made difficult by elevation of the right ventricular end diastolic pressures allowing only very brief and limited opening of the valve during atrial systole. The valve is best imaged from the apical view with mild anterior angulation toward the left ventricular outflow tract. The anterior angulation is especially helpful with more severe degrees of hypoplasia. The valve can also be imaged from the subcostal coronal and parasternal views. Measurement of the valve annulus should be taken at the hingepoints of the valve with the valve open ŽFig. 1.. The tricuspid valve annulus Z-score can then be calculated compared to lab normals or can be obtained from a nomogram w16x. The tricuspid valve annulus size and Z-score have been closely correlated to right ventricular size w5,7,10,11,17x as right ventricular volume measurements have been felt by some to be inaccurate by both echocardiography and angiography due to the heavy trabecular patterns. The tricuspid valve annulus size and Z-score have also been closely correlated to the presence of right ventricular to coronary artery communications. Because the presence of important right ventricular to coronary artery communications are the primary impediment to early right ventricular decompression w18x identifying their presence has an impact on the early management. The tricuspid valve can often erroneously be thought to be atretic due to difficulties in imaging the actual opening of the leaflets. In our experience, any patient with pulmonary atresia, intact ventricular septum, and an identifiable right ventricular chamber has a patent tricuspid valve. Those with both tricuspid and pulmonary atresia generally have a slit-like right ven-
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
167
Fig. 1. Apical four chamber view of the tricuspid valve. Cursors mark the measurement of the tricuspid annulus at the hingepoints of the valve. RA, right atrium; LA, left atrium; RV, right ventricle; LV, left ventricle.
tricle that is often difficult to identify. Doppler evaluation of the tricuspid valve can also be helpful in evaluating patency of the tricuspid valve, however, care must be taken to decrease the color velocity scale. With typical velocity color settings very low flow velocities, such as seen across the tricuspid valve, are not displayed. With decreasing of the color scale the tricuspid inflow signals can be visualized by color Doppler primarily during atrial contraction. Tricuspid insufficiency can also be evaluated by color and spectral Doppler. Nearly all patients with pulmonary atresia and intact ventricular septum will have suprasystemic right ventricular pressures and thus the tricuspid insufficiency jet velocities are elevated and can be used to estimate the right ventricular pressure. The degree of tricuspid insufficiency is generally inversely related to the presence of right ventricular to coronary communications. Thus, those patients with little or no tricuspid insufficiency are more likely to have right ventricular to coronary artery communications than those with severe insufficiency w8,14x. Many studies have sought to identify the tricuspid valve annulus size, and hence right ventricular size, that is predictive of the ability to achieve a biventricular repair. In a small patient group McCaffrey et al. w19x evaluated five patients in whom successful right ventricular decompression was accomplished. They concluded that successful outcome, achieving biventricular repair, can be attained in patients whose tricuspid valve diameter was )rs0.75 cm Ž Z-score y2.5 for BSA 0.2 m2 . or the tricuspidrmitral valve
ratio was )rs0.70. The smallest tricuspid valve annulus size in whom a biventricular repair was actually achieved was, however, 0.85 cm. De Leval et al. w13x reviewed data from 51 patients with a small right ventricle who underwent a definitive repair. Among patients in whom a biventricular repair was attempted, survival was highly associated with tricuspid valve size above the lower 99% confidence limit for normal. Bull et al. w20x recalculated the threshold above which deLeval and associates thought biventricular repair could be contemplated, in terms of unadjusted standard deviation units, and produced a guideline of Z ) y2.4. Hanley et al. w11x likewise concluded that the only patient-specific risk factor for not receiving a two-ventricle repair was the Z-value of the tricuspid valve. Giglia et al. w17x reviewed 37 neonates with pulmonary atresia and intact ventricular septum. They found that while right ventricular volume and tricuspid valve diameter were significantly smaller in patients with right ventricular-dependent coronary communications than in those without them, there was no statistically significant association between right ventricular volume or tricuspid valve annulus diameter and survival among patients with or without right ventricular-dependent coronary communications. 1.5. E¨ aluation of right ¨ entricular morphology and size Several studies have documented the ability of even moderate to severely hypoplastic right ventricles to
168
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
grow w3,4,21x and at this end of the spectrum the primary limitation to successful right ventricular decompression appears to be the presence of important right ventricular to coronary artery communications w18,22x. Quantitative assessment of right ventricular volume can be difficult as the myocardial hypertrophy and deep trabeculations make consistency a problem using any technique. Some authors, however, have been able to successfully obtain right ventricular volumes by echocardiography which correlate well to angiographic volumes w3x as well as outcome measured by the ability to achieve biventricular repair w5x. Right ventricular volumes have been measured in the subcostal coronal and sagittal views. The endocardial border at end diastole is measured to include the papillary muscles. The volume is then calculated using biplane Simpson’s rule algorithm w3,5,17x. Alternatively, some have used qualitative assessments of right ventricular size w10,11,23x. Billingsly et al. w23x described surgical management based upon comparison of the right ventricular size, visualized by the right ventricular inflow portion as imaged in the apical view, to that of the left ventricular size. Patients in whom the right ventricular size is at least 2r3 normal size are described as mild hypoplasia, 1r3᎐2r3 normal as moderate hypoplasia, and less than or equal to 1r3 normal as severe hypoplasia. Right ventricular morphology has also been examined. The patency and size of the right ventricular outflow tract appears to have significant importance both in the prediction of right ventricular to coronary artery communications w14x and to the ability for the right ventricle to be successfully decompressed without an outflow patch w22,24x. The right ventricular outflow tract can be best imaged from the subcostal, apical and parasternal views. Adequate imaging from the parasternal views depends upon the size of the right ventricular outflow tract. Division of patients has primarily been based upon ‘patency’ of the right ventricular outflow tract. Patent outflow tracts are those that remain patent up to an atretic membrane which separates it from the main pulmonary artery. The second group termed ‘muscular atresia’ has tapering of the outflow tract that may end blindly proximal to the main pulmonary artery. 1.6. E¨ aluation of the pulmonary ¨ al¨ e, main pulmonary artery and branch pulmonary arteries Like the right ventricular outflow tract, the pulmonary valve and main pulmonary artery can best be imaged from the parasternal views. Care must be taken not to mistake the left atrial appendage for the main pulmonary artery. The valve which is usually completely atretic, however, can have pinhole pa-
tency. The main pulmonary artery and branches are usually well developed due to presence of retrograde flow via the ductus arteriosus w8x, however, there have been cases of absence of the main andror branch pulmonary arteries with pulmonary blood flow supplied through aorticopulmonary collaterals. The main and branch pulmonary arteries are best imaged in the parasternal and high parasternal or suprasternal views. Presence and size of the ductus arteriosus are important for the initial decision-making and adequacy of the dose of prostaglandin. 1.7. E¨ aluation of the coronary circulation and presence of right ¨ entricular to coronary artery communications The ability to identify which patients are likely to have right ventricular to coronary artery communications, and more specifically right ventricular-dependent coronary circulation, has arguably become one of the most important determinants of early management w18x. Imaging of the coronary arteries in patients with pulmonary atresia with intact septum has improved significantly with improved imaging technology. The coronary ostia can be identified along with the major branches of the coronary arteries, however, coronary angiography remains necessary to completely evaluate patients for the location and size of fistulous communications and more distal coronary stenoses. Because the right ventricular to coronary artery communications occur primarily to the right coronary and left anterior descending coronary vessels these should be imaged in the parasternal long and short axis views. In patients with patent coronary ostia and right ventricular communications to the coronary artery, spectral Doppler will reveal antegrade flow into the coronary artery during diastole with systolic flow reversal ŽFig. 2.. In certain patients with large fistulae, the coronary artery with the fistula may become quite dilated ŽFig. 3.. In patients with complete ostial atresia or significant proximal stenosis, only retrograde flow during systole is visualized distal to the obstruction due to filling primarily from the right ventricle. Often imaging of the right ventricular apex with color Doppler will identify fistula which are often present at the right ventricular apex. Markers such as the tricuspid valve annulus size and Z-score have been quite useful in identifying those patients at highest risk for the presence of right ventricular to coronary artery communications w12x. In addition, in our laboratory, we have found the diameter of the right ventricular infundibulum to be an accurate predictor as well. Both the tricuspid valve annulus size and Z-score and the morphology of the right ventricular outflow tract have shown strong correlation to the presence of right ventricular to coronary artery communications, however, neither of these
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
169
Fig. 2. Spectral Doppler interrogation of a coronary artery in a patient with right ventricular to coronary artery communications. There is to and fro flow within the coronary artery with retrograde flow in the coronary artery during systole Žrepresented below the baseline . and antegrade flow during diastole Žrepresented above the baseline ..
markers has been able to distinguish those patients with right ventricular-dependent coronary circulation. Satou et al. w12x compared the tricuspid valve Z-scores of 30 patients with pulmonary atresia and intact ventricular septum to their coronary artery pathology by angiography. The coronary artery pathology was
graded as: 0 s no fistulae; 1 s fistulaerno right ventricular-dependent coronary arteries; 2 s fistulae with one right ventricular-dependent coronary; 3 s fistulae with )rs2 right ventricular-dependent coronary arteries. While all patients with a tricuspid valve Z-score of ᎐2.0 had coronary fistulae, none of those with
Fig. 3. Parasternal short axis image of a dilated right coronary artery Žcourse indicated by the arrows. in a patient with large right ventricular to coronary artery communications.
170
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
significant coronary artery pathology Žgrade 2 or 3 coronary pathology. had Z-scores of ) y2.5. 1.8. E¨ aluation of the mitral ¨ al¨ e and left ¨ entricle
The mitral valve is usually normal in these patients, however, they can have isolated abnormalities such as clefts or double orifice valves w8x. Left ventricular function and regional wall motion abnormalities should be carefully assessed as it has been shown that these patients can have left ventricular wall motion abnormalities both due to ischemia and independently to effects of elevated right ventricular filling pressure w25᎐30x. Myocardial ischemia and infarction have been described to occur prenatally w31x. The wall motion of the interventricular septum is usually abnormal prior to intervention due to the suprasystemic right ventricular pressure. There can be bulging of the interventricular septum into the left ventricular outflow tract, however, significant left ventricular outflow tract obstruction has not been described. The left ventricular wall motion is best assessed in the apical view and parasternal views. Akagi et al. w25x reviewed 21 patients by cardiac catheterization to assess the influence of right ventricular to coronary artery communications on left ventricular performance. They found left ventricular wall motion abnormalities in eight patients, seven of which had coronary artery abnormalities. Those with wall motion abnormalities also had significantly lower ejection fraction Ž50 " 6 vs. 57 " 7%. and significantly higher right-to-left ventricular systolic pressure ratio Ž1.46" 0.16 vs. 0.8" 0.45. than in those with normal wall motion. During the follow-up five patients, all with abnormal wall motion, died. Gentles et al. w26x evaluated the effect of right ventricular decompression on left ventricular function in patients with less extensive coronary artery abnormalities Žfistula alone or with one coronary artery stenosis.. They analyzed pre-operative and post-operative echocardiograms for global and regional left ventricular function in 24 patients. There was no significant difference in the global left ventricular function between those with and without coronary artery abnormalities before or after right ventricular decompression. After right ventricular decompression three patients developed depressed left ventricular ejection fractions, all of whom had regional wall motion abnormalities and coronary artery abnormalities. In those with coronary artery abnormalities regional dysfunction occurred in areas supplied by abnormally connected or stenosed coronary arteries. Regional left ventricular dysfunction was rare in patients without coronary artery abnormalities.
1.9. E¨ aluation of the aortic ¨ al¨ e and aortic arch The aortic valve and aortic arch are usually normal, however, there have been rare patients with associated valvar aortic stenosis w8x. This has been encountered rarely in our institution as well and these patients have a high mortality. We have not encountered any patients with aortic arch anomalies. The aortic valve can be imaged in the subcostal coronal, apical, and parasternal long axis views to evaluate for doming of the valve leaflets and to obtain gradients by Doppler evaluation. The cuspal morphology can best be viewed from the parasternal short axis view.
2. Post procedure evaluation In general, patients will fall into two categories of management based in large part upon the coronary artery circulation and the patency of the right ventricular outflow tract. This will distinguish patients in whom right ventricular decompression is deemed unsafe and will usually involve placement of a systemic to pulmonary shunt alone vs. patients in whom decompression of the right ventricle is attempted. Currently, the second group may have right ventricular decompression performed in the cardiac catheterization laboratory with perforation of the valve if necessary followed by pulmonary valvuloplasty or surgical intervention via either a valvotomy andror right ventricular outflow tract patch. In addition, some of the patients in whom right ventricular decompression is performed may require an additional source of pulmonary blood flow in the form of a systemic to pulmonary artery shunt. 2.1. E¨ aluation status post placement of systemic to pulmonary artery shunt As stated above, patients in whom a systemic to pulmonary artery shunt is performed without decompression of the right ventricle tend to have significant coronary artery pathology and are felt to have a coronary circulation whose perfusion is dependent upon preservation of right ventricular hypertension. In this group of patients the long-term follow-up generally focuses upon patency of the shunt and left ventricular function with an emphasis upon segmental wall motion. The left ventricular function should be followed closely due to the risk for development of coronary stenoses or occlusion due to intimal proliferation at the sites of right ventricular to coronary fistulae w32᎐34x. Without decompression establishing
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
flow through the right ventricle, the right ventricle and tricuspid valve do not grow in proportion to the somatic growth of the patient and thus become relatively smaller as the patient grows. 2.2. E¨ aluation status post right ¨ entricular decompression Decompression of the right ventricle can take many forms including perforation of the valve and valvuloplasty during cardiac catheterization, surgical valvotomy, and placement of a right ventricular outflow tract patch. In general, the follow-up regardless of the approach involves: Ž1. early evaluation assessing the need for an additional shunt; Ž2. adequacy of decompression and right ventricular pressure; Ž3. assessment of growth of the right ventricle and tricuspid valve; and Ž4. assessment of left ventricular function. 2.3. E¨ aluating the need for an additional shunt Several studies have addressed management of neonates after surgical valvotomy w7,11,13,19᎐ 21,35᎐38x and it has become clear that the combination of elevated pulmonary vascular resistance and poor right ventricular compliance in the early postoperative period combine to limit pulmonary blood flow such that shunts are often placed at the time of right ventricular decompression. The use of prolonged prostaglandin therapy after pulmonary valvotomy has been shown to bridge many patients through this period avoiding placement of a subsequent shunt w19,35,36x. Trowitzsch et al. w5x reported on echocardiographic predictors for those patients in whom an additional shunt will be required. They reviewed 15 patients with either critical pulmonary stenosis or pulmonary atresia and intact ventricular septum and compared the normalized right ventricular end diastolic volume ŽRVEDV., tricuspid valve annulus diameter, wall thickness, area change fraction and ejection fraction in those patients who required an additional shunt vs. those that did not. In the group of patients with RVEDV - 5.0 mlrm2 the shunt was performed as part of the initial procedure thus making the requirement for the shunt uncertain. They found that relief of right ventricular outflow tract obstruction alone provided adequate palliation in all patients with normalized right ventricular end diastolic volume of ) 11 mlrm2 . In those with normalized RVEDV - 5 mlrm2 or tricuspid valve annulus dimension of - 1 cmrm 2r3 all required a shunt. In the intermediate group Žnormalized RVEDV between 5.0 and 11 mlrm2 ., all with a normalized RVEDV - 6.0 mlrm2 or a tricuspid valve diameter of - 1.4 cmrm 2r3 required a subsequent shunt while those with an RVEDV )rs6.0 mlrm2 and tricuspid di-
171
ameter of )rs1.4 cmrm 2r3 did not require an additional shunt. Wall thickness, area change fraction and ejection fraction measurements did not significantly correlate with right ventricular volume or post-operative outcome. They concluded that if either the ventricular volume or tricuspid annulus size is excessively small, a shunt procedure is necessary. Steinberger et al. w36x reviewed 15 patients in whom a right ventricular outflow tract patch was performed as the initial surgery during the neonatal period without an additional shunt. The patients were maintained on prostaglandin post-operatively and criteria for weaning prostaglandin was based on Doppler assessment of increasing antegrade tricuspid flow and clinical evidence of satisfactory pulmonary blood flow. Only 1 of 15 subsequently required a shunt and 11 of these had measurements of the tricuspid valve diameter. The tricuspid valve diameters ranged from 7 to 12 mm in patients not requiring a subsequent shunt and was 8 mm in the patient that required a shunt. Right ventricular volume measurements were available for 14 patients and ranged from 2.7 to 48 mlrm2 in those not requiring a shunt and was 3.5 mlrm2 in the patient that subsequently required a shunt. They concluded that early placement of a right ventricular outflow patch regardless of right ventricular anatomy results in good long-term palliation with an excellent chance for biventricular repair. 2.4. Adequacy of right ¨ entricular decompression and estimation of right ¨ entricular pressure The approach to right ventricular decompression is made primarily upon establishing patency of the right ventricular outflow tract and pulmonary valve. In patients with membranous atresia and a widely patent outflow tract, either perforation and valvuloplasty during cardiac catheterization or surgical valvotomy can adequately relieve the obstruction whereas those patients with tapering or hypoplastic outflow tracts often require a right ventricular outflow patch. Evaluation of the adequacy of right ventricular decompression after these procedures is vitally important as subsequent growth of the right ventricle depends upon resolution of the hypertrophy and improvement of right ventricular compliance w20x. By two-dimensional imaging the right ventricular outflow tract and pulmonary valve can be imaged from subcostal, apical and parasternal views. The right ventricular outflow tract is examined for the presence of dynamic narrowing with systole that can often occur once the afterload is acutely reduced. The valve should be assessed for annulus size and visualization of the orifice. By color Doppler, the flow across the outflow tract and valve can be further assessed for turbulence and narrowing of the jet. The severity of residual stenosis can be
172
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
quantified by measuring the peak and mean gradients across the pulmonary valve. If significant subvalvar obstruction is present the modified Bernoulli equation should be used. Any dynamic right ventricular outflow tract obstruction will often have the characteristic late peaking flow profile which distinguishes it from residual fixed obstruction at the level of the valve annulus. Measuring the right ventricular pressure provides an indirect estimate of residual obstruction to right ventricular outflow. The right ventricular pressure can be quantitated directly by measuring the peak gradient of the tricuspid valve insufficiency jet. One must assume both the right atrial pressure and the pulmonary artery pressure to calculate the degree of residual right ventricular outflow tract obstruction. The latter estimate can be inaccurate in the presence of a ductus arteriosus, systemic to pulmonary artery shunt, and during the neonatal period as the pulmonary vascular resistance remains variably elevated. Observing the curvature of the interventricular septum during systole can be useful as a qualitative estimate of differentiating right ventricular pressure as subsystemic, systemic, or suprasystemic. Indirect evidence of adequacy of right ventricular decompression includes patterns of diastolic filling. Findings of a large A wave opening on the pulmonary artery Doppler is an indicator of a stiff, non-compliant right ventricle w39x. 2.5. Assessment of growth of the tricuspid ¨ al¨ e and right
¨ entricle
Most early studies aimed at measuring tricuspid valve and right ventricular growth utilized angiographic measurements w7,13,21,35,37,38x, however, more recent studies have provided echocardiographic assessment w3,4,17,20,36x. Schmidt et al. w3x evaluated the early changes in right ventricular volume, area ratio and stroke volume before and at an average of 5 days and 19 days after pulmonary valvotomy. All patients except one had right ventricular hypoplasia before valvotomy. They found that at 5 days after valvotomy the RVEDV decreased from 16.6" 6.4 to 10.6" 4.6 mlrm2 and the stroke volume decreased from 8.3" 3.5 to 5.5" 2.8 mlrm2 . The right ventricular area ratio also decreased from 0.56" 0.09 to 0.39" 0.08. By the second evaluation at 19 days post-valvotomy the RVEDV had reached the preoperative size of 18 " 6.2 mlrm2 as had the right to left ventricular area ratio 0.55" 0.08. Importantly, the right ventricular stroke volume had increased to 10.4" 3.9 mlrm2 from 8.3" 3.5 mlrm2 . Their echocardiographic measures of RVEDV and stroke volume correlated closely with angiographic measurements. They concluded that right ventricular
volumes can be accurately measured by echocardiography and that because of the early decrease in right ventricular size after decompression an additional source of pulmonary blood flow may be necessary to support these neonates and may aid in determining timing for weaning of prostaglandin. Hanseus et al. w4x evaluated right ventricular growth in 10 patients with critical pulmonary stenosis or pulmonary atresia and intact septum that survived right ventricular decompression. They utilized measurement of the right ventricular cross-sectional area obtained from the ventricular length and width in the apical or subcostal four chamber views. This was expressed in standard deviation from the normal mean based on body surface area. They concluded that in all seven patients with a normal right ventricle at follow-up, right ventricular to pulmonary artery communication had been established in the neonatal period. The three patients in whom right ventricular growth into the normal range was not achieved had absent or ineffective flow through the right ventricle during the first months of life. Steinberger et al. w36x evaluated tricuspid valve and right ventricular growth in 15 survivors of neonatal right ventricular outflow tract patch placement. They were divided into two groups based on right ventricular morphology with group 1 composed of tripartite right ventricle and group 2 with unipartite or bipartite ventricular morphology. Average follow-up was 5.8 years Žrange 1.5᎐11 years.. In group 1, mean right ventricular volume increased from 23.6" 3.7 to 50.7 " 7.7 mlrm2 . In group 2, mean right ventricular volume increased from 5.2" 1.1 to 38.5" 7.7 mlrm2 . There was a comparative increase in tricuspid valve annulus size from 11.7" 1.4 to 23.5" 2.2 mm in group 1 and from 9.2" 0.8 to 21 " 3 mm in group 2. Twelve of these 15 survivors had biventricular physiology while three were awaiting evaluation for biventricular repair. 2.6. Assessment of left ¨ entricular function Post-operative assessment of left ventricular function is important particularly in two instances. First, those patients in whom right ventricular to coronary artery communications are present prior to right ventricular decompression. These patients can develop left ventricular dysfunction early after decompression due to dependence of the coronary circulation on right ventricular hypertension or later due to progressive intimal hyperplasia within the coronary artery resulting in late stenosis or occlusion w32᎐34x. Second, in patients in whom right ventricular decompression was unsuccessful with abnormal septal motion.
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175
3. Prenatal diagnosis of pulmonary atresia with intact ventricular septum Fetal echocardiography became established as a reliable tool for prenatal diagnosis of congenital heart disease in the early 1980s. The spectrum of congenital heart disease diagnosed prenatally is skewed to more severe forms of malformations. Because of this, the incidence of pulmonary atresia with intact ventricular septum diagnosed in utero tends to be higher than in the live born population. Early in their experience Allan et al. w39x described that five of seven cases diagnosed prenatally had severe tricuspid insufficiency and dilated right ventricles whereas only two of seven had right ventricular hypoplasia. However, later in their experience w40x this ratio has reversed. The form of pulmonary atresia with intact ventricular septum and right ventricular hypoplasia is less obvious requiring a higher degree of expertise of the sonographer. They attributed this shift in pattern of prenatal diagnosis to increasing expertise in general obstetric scanning as the majority of cases were referred because of suspicion of an abnormality on routine obstetric screening ultrasound. In the form of pulmonary atresia with intact septum with right ventricular hypoplasia the cardiothoracic ratio is usually within the normal range. As in postnatal patients, there are varying degrees of right ventricular size ranging from nearly normal in size to severely hypoplastic. The right ventricular walls are nearly always hypertrophied and endocardial fibroelastosis may be present with increased echogenicity of the endocardium. The right ventricular wall motion is often decreased reflecting the increased afterload caused by the atretic pulmonary valve. The tricuspid valve annulus is often hypoplastic and the tricuspid valve leaflet motion is usually diminished. One should carefully inspect the motion of both the tricuspid and pulmonary valves for motion using two-dimensional imaging from multiple planes if possible. The left heart structures are usually normal, however, there have been cases of associated valvar aortic stenosis. By color Doppler, the right ventricular outflow tract and pulmonary valve should be interrogated for any antegrade flow across them. The ductus arteriosus should also be interrogated for reverse flow, however, this has not been reliable in distinguishing stenosis from atresia w42x. One of the difficult aspects of fetal diagnosis that has been well established is the prenatal progression of the severity of some defects w41᎐48x. In general, the heart is formed by 7᎐8 weeks gestation, however, there are now multiple reports of progression of pulmonary valve stenosis to atresia between an initial echocardiogram at 18᎐20 weeks gestation and birth. Because the fetal circulation is in parallel rather than in series,
173
the flow through the right ventricle can vary which decreases the reliability of increased flow velocities across the pulmonary valve. This places increased emphasis on careful inspection of the thickness and motion of the pulmonary valve by two-dimensional imaging and attention to the relative right vs. left heart chamber sizes. Once flow ceases through the right ventricle its growth also fails to keep pace with the rest of the heart and this discrepancy in chamber sizes becomes more apparent. Thus, any patients with a diagnosis of pulmonary stenosis or atresia with intact ventricular septum should be counseled regarding the chances of progression and monitored closely throughout pregnancy. Daubeney et al. w49x have published their experience of prenatal diagnosis in the United Kingdom. They found a decrease in the incidence of pulmonary atresia and intact ventricular septum diagnosed after birth and attributed this to the fact that many of their patients choose to interrupt the pregnancy. Prenatal intervention has been attempted sporadically, however, many have been unsuccessful for technical problems. Unfortunately, of the valves that have been opened, most have again become stenosed prior to birth.
4. Conclusions Many studies mentioned here appear to direct us to similar conclusions. First that patients with a tricuspid valve Z-score of )rsy2.5 are at very low risk for having right ventricular-dependent coronary circulation and a very high likelihood of achieving a biventricular repair provided they achieve successful right ventricular decompression early in life. Right ventricular decompression can be successfully performed by either valvuloplasty in the catheterization lab or by surgical valvotomy in those patients with a patent infundibulum, however, those patients with a tapering or hypoplastic infundibulum this may require placement of an outflow patch. References w1x Bonnet D, Gautier-Lhermitte I, Bonhoeffer P, Sidi D. Right ventricular myocardial sinusoidal᎐coronary artery connections in critical pulmonary valve stenosis. Pediatr Cardiol 1998;19:269᎐271. w2x Weldon CS, Hartmann AF, McKnight RC. Surgical management of hypoplastic right ventricle with pulmonary atresia or critical pulmonary stenosis and intact ventricular septum. Ann Thorac Surg 1984;37Ž1.:12᎐22. w3x Schmidt KG, Cloez JL, Silverman NH. Changes of right ventricular size and function in neonates after valvotomy for pulmonary atresia or critical pulmonary stenosis and intact ventricular septum. J Am Coll Cardiol 1992;19Ž5.:1032᎐1037. w4x Hanseus K, Bjorkhem G, Lundstrom NR, Laurin S. Crosssectional echocardiographic measurements of right ventricu-
174
w5x
w6x w7x w8x
w9x w10x w11x
w12x
w13x w14x w15x w16x w17x w18x
w19x w20x
w21x w22x
w23x
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175 lar size and growth in patients with pulmonary atresia and intact ventricular septum. Pediatr Cardiol 1991;12:135᎐142. Trowitzsch E, Colan SD, Sanders SP. Two-dimensional echocardiographic evaluation of right ventricular size and function in newborns with severe right ventricular outflow tract obstruction. J Am Coll Cardiol 1985;6:388᎐393. Leung MP, Mok CK, Hui PW. Echocardiographic assessment of neonates with pulmonary atresia and intact ventricular septum. J Am Coll Cardiol 1988;12:719᎐725. Patel RG, Freedom RM, Moes CAF et al. Right ventricular volume determinations in 18 patients with pulmonary atresia and intact ventricular septum. Circulation 1980;61Ž2.:428᎐440. Freedom RM, Wilson G, Trusler GA, Williams WG, Rowe RD. Pulmonary atresia and intact ventricular septum: a review of the anatomy, myocardium, and factors influencing right ventricular growth and guidelines for surgical intervention. Scand J Thor Cardiovasc Surg 1982;17:1᎐28. Freedom RM. The morphologic variations of pulmonary atresia with intact ventricular septum: guidelines for surgical intervention. Ped Cardiol 1983;4:183᎐188. Bull C, deLeval MR, Mercanti C, Macartney FJ, Anderson RH. Pulmonary atresia and intact ventricular septum: a revised classification. Circulation 1982;66Ž2.:266᎐271. Hanley FL, Sade RM, Blackstone EH, Kirklin JW, Freedom RM, Nanda NC. Outcomes in neonatal pulmonary atresia with intact ventricular septum. A multiinstitutional study. J Thorac Cardiovasc Surg 1993;105:406᎐427. Satou GM, Perry SB, Gauvreau K, Geva T. Echocardiographic predictors of coronary artery pathology in pulmonary atresia with intact ventricular septum. Am J Cardiol 2000; 85:1319᎐1324. De Leval M., Bull C., Hopkins R. et al. Decision making in the definitive repair of the heart with a small right ventricle. Circulation 1985; 72 Suppl II: II52᎐II60. Anderson RH, Anderson C, Zuberbuhler JR. Further morphologic studies on hearts with pulmonary atresia and intact ventricular septum. Cardiol Young 1991;1:105᎐113. Choi YH, Seo JW, Choi JY, Yun YS, Kim SH, Lee HJ. Morphology of tricuspid valve in pulmonary atresia with intact ventricular septum. Pediatr Cardiol 1998;19:189᎐381. Kirklin JW, Barratt-Boyes BG. Cardiac surgery. 2nd ed., chap 1 New York: Churchill Livingstone, 1992. Giglia TM, Jenkins KJ, Matitiau A et al. Influence of right heart size on outcome in pulmonary atresia with inact ventricular septum. Circulation 1993;88Žpart 1.:2248᎐2256. Giglia TM, Mandell VS, Connor AR, Mayer JE, Lock JE. Diagnosis and management of right ventricle-dependent coronary circulation in pulmonary atresia with intact ventricular septum. Circulation 1992;86:1516᎐1528. McCaffrey FM, Leatherbury L, Moore HV. Pulmonary atresia and intact ventricular septum. Definitive repair in the neonatal period. J Thorac Cardiovasc Surg 1991;102:617᎐623. Bull C, Kostelka M, Sorensen K, de Leval M. Outcome measures for the neonatal management of pulmonary atresia with intact ventricular septum. J Thorac Cardiovasc Surg 1994;107:359᎐366. Lewis AB, Wells W, Lindesmith GG. Right ventricular growth potential in neonates with pulmonary atresia and intact ventricular septum. J Thorac Cardiovasc Surg 1986;91:835᎐840. Mainwaring RD, Lamberti JJ. Pulmonary atresia with intact ventricular septum ᎏ surgical approach based on ventricular size and coronary anatomy. J Thorac Cardiovasc Surg 1993;106:733᎐738. Billingsly AM, Laks H, Boyce SW, George B, Santulli T, Williams RG. Definitive repair in patients with pulmonary atresia and intact ventricular septum. J Thorac Cardiovasc Surg 1989;97:746᎐754.
w24x Pawade A, Capuani A, Penny DJ, Karl TR, Mee RBB. Pulmonary atresia with intact ventricular septum: surgical management based on right ventricular infundibulum. J Card Surg 1993;8:371᎐383. w25x Akagi T, Benson LN, Williams WG et al. Ventriculo-coronary arterial connections in pulmonary atresia with intact ventricular septum, and their influences on ventricular performance and clinical course. Am J Cardiol 1993;72:586᎐590. w26x Gentles TL, Colan SD, Giglia TM, Mandell VS, Mayer JE, Sanders SP. Right ventricular decompression and left ventricular function in pulmonary atresia with intact ventricular septum: the influence of less extensive coronary anomalies. Circulation 1993;88Žpart 2.:183᎐188. w27x Sideris EB, Olley PM, Spooner E et al. Left ventricular function and compliance in pulmonary atresia with intact ventricular septum. J Thorac Cardiovasc Surg 1982;84: 192᎐199. w28x Freedom RM, Harrington DP. Contributions of intramyocardial sinusoids in pulmonary atresia and intact ventricular septum to a right-sided circular shunt. Br Heart J 1974; 36:1061᎐1065. w29x Taylor RR, Covell JW, Sonnenblick EH, Ross J. Dependence of ventricular distensibility on filling of the opposite ventricle. Am J Physiol 1967;213Ž3.:711᎐718. w30x Bemis CE, Serur JR, Borkenhagen D, Sonnenblick EH, Urschel CW. Influence of right ventricular filling pressure on left ventricular pressure and dimension. Circ Res 1974;34: 498᎐504. w31x Koike K, Perrin D, Wilson GJ, Freedom RM. Myocardial ischemia and coronary arterial involvement in newborn babies less than one week old with pulmonary atresia and intact ventricular septum. In: Freedom RM, editor. Pulmonary atresia with intact ventricular septum. Mount Kisco, NY: Futura Publishing Company, Inc., 1989:101᎐107. w32x Fyfe DA, Edwards WD, Driscoll DJ. Myocardial ischemia in patients with pulmonary atresia and intact ventricular septum. J Am Coll Cardiol 1986;8:402᎐406. w33x Wilson GJ, Freedom RM, Koike K, Perrin D. The coronary arteries: anatomy and histopathology. Pulmonary atresia with intact ventricular septum. Mount Kisco, NY: Futura Publishing Company, Inc., 1989 75᎐88. w34x Gittenberger-de Groot AC, Sauer U, Bindl L, Babic R, Essed CE, Buhlmeyer K. Competition of coronary arteries and ventriculo-coronary arterial communications in pulmonary atresia with intact ventricular septum. Int J Cardiol 1988; 18:243᎐258. w35x Foker Je, Braunlin EA, Cyr St. JA et al. Management of pulmonary atresia with intact ventricular septum. J Thorac Cardiovasc Surg 1986;92:706᎐715. w36x Steinberger J, Berry JM, Bass JL et al. Results of a right ventricular outflow patch for pulmonary atresia with intact ventricular septum. Circulation 1992;86ŽSuppl II.:II167᎐II175. w37x Amodeo A, Keeton BR, Sutherland GR, Monro JL. Pulmonary atresia with intact ventricular septum: is neonatal repair advisable? Eur J Cardio-thorac Surg 1991;5:17᎐21. w38x Shaddy RE, Sturtevant Je, Judd VE, McGough EC. Right ventricular growth after transventricular pulmonary valvotomy and central aortopulmonary shunt for pulmonary atresia and intact ventricular septum. Circulation 1990;82ŽSuppl IV.:IV157᎐IV163. w39x Snider RA, Serwer GA, Ritter SB. Echocardiography in pediatric heart disease. 2nd ed. St. Louis, MO: Mosby, 1997. Chapter 5 w40x Allan LD, Crawford DC, Tynan MJ. Pulmonary atresia in prenatal life. J Am Coll Cardiol 1986;8:1131᎐1136. w41x Allan LD, Cook A. Pulmonary atresia with intact ventricular septum in the fetus. Cardiol Young 1992;2:367᎐376.
S.E. Drant r Progress in Pediatric Cardiology 13 (2001) 165᎐175 w42x Hornberger LK, Benacerraf BR, Bromley BS, Spevak PJ, Sanders SP. Prenatal detection of severe right ventricular outflow tract obstruction: pulmonary stenosis and pulmonary atresia. J Ultrasound Med 1994;13:743᎐750. w43x Allan LD. Development of congenital lesions in mid or late gestation. Int J Cardiol 1988;19:361᎐362. w44x Hornberger LK, Sanders SP, Sahn DJ et al. In utero pulmonary artery and aortic growth and potential for progression of pulmonary outflow tract obstruction in tetralogy of fallot. J Am Coll Cardiol 1995;25:739᎐745. w45x Hornberger LK, Sanders SP, Azaria JJT et al. Left heart obstructive lesions and left ventricular growth in the midtrimester fetus. Circulation 1995;92:1531᎐1538.
175
w46x Rice MJ, McDonald RW, Reller MD. Progressive pulmonary stenosis in the fetus: two case reports. Am J Perinatol 1993;10Ž6.:424᎐427. w47x Guntheroth WG, Cyr DR, Winter T, Easterling T, Mack LA. Fetal Doppler echocardiography in pulmonary atresia. J Ultrasound Med 1993;5:281᎐284. w48x Allan LD, Sharland G, Tynan MJ. The natural history of the hypoplastic left heart syndrome. Int J Cardiol 1989; 25:341᎐343. w49x Daubeney PEF, Sharland GK, Cook AC, Keeton BR, Anderson RH, Webber SA. Pulmonary atresia with intact ventricular septum: impact of fetal echocardiography on incidence at birth and postnatal outcome. Circulation 1998;98:562᎐566.