The dimensions of the right ventricular outflow tract and pulmonary arteries in tetralogy of Fallot and pulmonary stenosis

The dimensions of the right ventricular outflow tract and pulmonary arteries in tetralogy of Fallot and pulmonary stenosis Studies were undertaken of the cineangiograms in 196 consecutive patients entering two institutions with tetralogy of Fallot and pulmonary stenosis, none of whom had previously undergone a surgical procedure. The median age of the patients at the time of the study was 5.9 months. The diameters of the right ventricular infundibulum, pulmonary trunk, and the entirety of the right and left pulmonary arteries were measured (in millimeters), corrected for magnification, and expressed in standard deviation units (Z-values). The median values of the cineangiographicaUy determined diameters of the right ventricular infundibulum and pulmonary trunk were smaller than those of 95 % of normal individuals. The median values throughout the right and left pulmonary arteries were within the range of normal. Those of the distal branches of both the right and left pulmonary arteries were similar to the mean values in normal individuals. However, great variability of the dimensions between individuals, and along the pathway in individuals, characterized patients with tetralogy of Fallot. Diffuse narrowing of the pathways both proximally and distally was uncommon. The relation between the diameters of the pulmonary "anulus" and of the distal pulmonary trunk and origin of the left pulmonary artery explained the difficulty of extending an enlarging patch into a wide area distally in some patients. (J THORAC CARDIOVASC SURG 1992;103:692-705)

Y. Shimazaki, MD,* E. H. Blackstone, MD, J. W. Kirklin, MD, R. A. Jonas, MD,

V. Mandell, MD, and E. V. Colvin, MD, Birmingham, Ala., and Boston, Mass.

Athough the results of complete repair of tetralogy of Fallot with pulmonary stenosis have improved greatly since the first successful repair in 1954, I deaths still occur occasionally in the early postoperative period and occasional patients have considerable right ventricular hypertension after repair, even when a transannular patch has been used.v" Correlations and predictions of these unfavorable outcome events based on dimensions of the pulmonary arteries have had wide confidence intervals and thus have not been as useful in individual patients as is desirable. 5-7 From the Divisions of Cardiothoracic Surgeryand PediatricCardiology,University of Alabamaat Birmingham School of Medicine and Medical Center, Birmingham, Ala., and the Departments of Cardiovascular Surgeryand Radiology, Harvard Medical School, and The Boston Children's Hospital, Boston, Mass. Address for reprints: John W. Kirklin, MD, Professor of Surgery,University of Alabamaat Birmingham, UABStation,Birmingham, AL 35294.

Received for publication May 3, 1991. Accepted for publication Sept. 3, 1991. *Current address: Osaka University Medical School, Osaka, Japan. 12/1/33685

692

Therefore a study in two institutions was undertaken to obtain new basic information relevant to these problems.

Material and methods One hundred consecutive cineangiograms of patients with tetralogy of Fallot and pulmonary stenosis made at the University of Alabama Medical Center at Birmingham (UAB) and 100 made at the Boston Children's Hospital (BCH) were studied. Patients with pulmonary atresia, with absent pulmonary valve, or having undergone a prior surgical procedure were excluded. In both institutions, the cineangiograms of patients catheterized in December 1988 were identified, and then, working backward, the patients studied earlier were added consecutively until 100 patients were included. This took the identification process back to September 1984. Subsequently four patients were deleted because they later were found to have absent pulmonary valves, and thus the study group consisted of 196 patients. The median age of the 196 patients at the time of the study was 5.9 months (Fig. 1, A); it was 5.1 months in the patients at BCH and 11.8 months in those at UAB (Fig. I, B). Associated cardiac and noncardiac anomalies coexisted with the tetralogy of Fallot in some patients (Table I). The cineangiograms of the 196 patients were reviewed in detail, without knowledge of the subsequent clinical course. The diameters of the right ventricular infundibulum, the right ven-

Volume 103 Number 4 April 1992

Tetralogy and pulmonary stenosis

693

100 QI

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90

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80

cs:

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10%

25% 50% 75% 90% max

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> 40

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72

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min 10% 25% 50% 75% 90% max

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2 days 1.8 months 3.2 months 5.1 months 10.3 months 22.5 months 5.7 years

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54

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Fig. 1. Cumulative frequency distribution of the age of the patients at the time of cardiac catheterization and cineangiography. A, The group of 196 patients. B, The patients in the two institutions depicted separately.

tricular--pulmonary trunk junction (pulmonary valve "anulus"), the pulmonary trunk, the right and left pulmonary arteries, and their first-order branches were measured at specific points (Fig. 2). The view and phase of the cardiac cycle (systole or diastole) that best depicted the structure was chosen for each measurement. All measurements were corrected for magnification, and the corrected values were used throughout the article. The bases of the transformation of the diameters in millimeters to Z-values were similar measurements of all of these dimensions, except those of the right ventricular infundibulum, made in cineangiograms of normal neonates, infants, and children, by Bini, Naftel, and Blackstone." Regression equations were developed, which expressed the relation between body surface area and the mean normal values and standard deviations of the dimensions in millimeters. A similar study by Sievers and colleagues." with remarkably similar findings, included also the dimensions of the infundibulum. Since the findings of the two studies were essentially identical for the pathway sites

included in both studies, including the form of the equations, Sievers' analysis and equations were used to obtain the Z-value for the infundibulum. The equations were used in the present study to transform the observed dimension in millimeters to the number of standard deviations from the mean normal value represented by that dimension. The following equation was derived for calculating the Z-value for each dimension in the present study in the manner described:

Z

=

In (diameter) -In (mean normal diameter) SD (In [normal diameter J)

-'------=~;--;---'-~--:-;--___;,.,___----'-

where: In (mean normal diameter) = scalefactor In (BSA)

+ exponent·

"Mean normal diameter" was the mean diameter in normal individuals of the same body surface area (BSA) as that of the

694

The Journal of Thoracic and Cardiovascular Surgery

Shimazaki et al.

Table I. Associated anomalies in patients (n = 196) with tetralogy of Fallot and pulmonary stenosis who had not had a prior operation Percent of Associated anomalies Cardiac Complete AV canal defects Large AP collateral arteries Multiple VSDs Anomalous origin of LAD from RCA Hypoplastic or abnormal tricuspid valve Hypoplastic RV Aortic incompetence Left SVC Patent ductus arteriosus (typical) Double aortic arch Interruption of IVC Absence or atresia of origin of LPA Anomalous origin of LP A from ascending aorta Partial anomalous pulmonary venous connection Noncardiac Down syndrome DiGeorge syndrome Hydrocephalus Noonan syndrome Trisomy 13 Microcephaly Tracheoesophageal fistula Anophthalmia

No.

196

13

6.6 3.6 2.6

7

5 6 4

3.1

2.0

2

1.0

I 7

0.5 3.6

2

1.0

I I 2 I

0.5 0.5

1.0 0.5 0.5

19 4 2 2 I I 4 I

9.7 2.0

1.0 1.0 0.5 0.5 2.0 0.5

Note: The categories are not mutually exclusive. Key: A V, Atrioventricular; AP, aortopulmonary; IVC, inferior vena cava; LAD, left anterior descending; LPA, left pulmonary artery; RCA, right coronary artery; RV, right ventricle; SVC, superior vena cava; VSD, ventricular septal defect.

patient; In is the natural logarithm, and SD is the standard deviation. The "scale factor" and "exponent" were specific for each anatomic location, for systole and diastole, and for anteroposterior and lateral projections, and were derived by Bini, Naftel, and Blackstone'' and by Sievers and colleagues." When the measurementwas made in an obliqueprojection, the values derived by Bini, Sievers, and their colleagues from the lateral projection were used. Becauseof the log-log form of the equations for calculating Z-value in these studies, the Z-values for the diameters and for the cross-sectional areas are identical, exceptfor the summedvaluesused to express these dimensions for the first-order branches of the right and left pulmonary arteries. The dimensions were also expressed as percent of normal diameter in patientsof the same bodysurfacearea, as diameter index (normalizedto body surface area), and as cross-sectional area index(this is the Nakata index'? whenthe dimensions are the summed valuesfor the prebranchingpointsofthe right and left pulmonary arteries) (Appendix A). The diameter of the descending aorta atthe diaphragmwasalsomeasured,and with this as the denominator,and the summeddiameters at the prebranching level of the right and left pulmonaryarteries as the numerator, the McGoon ratio!' was alsocomputed (Appendix A).

Results The median Z-values for the diameters of the right ventricular infundibulum, "anulus" (junction of the right ventricular infundibulum and pulmonary trunk), and the two levels in the pulmonary trunk were considerably smaller than those of 95% of normal individuals (Fig. 3). The diameters of the "anulus" and of the distal pulmonary trunk in individual patients were often similar one to the other (Fig. 4). However, in some patients the diameter of the distal pulmonary trunk was considerably smaller than that of the "anulus" (Fig. 4), and in some the "anulus" was considerably narrower than was the distal pulmonary trunk. The median value for the Z-value of the origin of the right pulmonary artery was just below the range of normal, and that for the origin of the left pulmonary artery was just within the range of normal (see Fig. 3, A). The Z-value of the origin of the right pulmonary artery, in individual patients, was usually similar to or larger than that of the distal pulmonary trunk (Fig. 5, A), as was that of the origin of the left pulmonary artery (Fig. 5, B). The median values for the diameters of the right and left pulmonary arteries beyond the origins were within the range of normal (Fig. 3), but the variability, expressed as Z-values, was considerably greater than in normal individuals. The origin of the right pulmonary artery in individual patients was usually narrower than were the midportion (Fig. 6, A) and the prebranching level (Fig. 6, B), although a few exceptions to this occurred, Severe hypoplasia (narrowness) of the origin of the left pulmonary artery occurred but was uncommon (Fig. 7). When it occurred, the midportion and prebranching areas were usually, but not always, similarly narrowed. The branches of the right and left pulmonary arteries were rarely importantly narrowed (see Fig. 3), even when severe hypoplasia existed proximally. Diffuse narrowing of the pulmonary trunk and right and left pulmonary arteries was very uncommon. Instead, in individual patients, the smaller the diameter of the most narrow point in the pulmonary trunk and right and left pulmonary arteries, the greater was the variability in the diameters along that pathway (Fig. 8). The descending aorta at the diaphragm was, in general, more narrow in these patients with tetralogy of Fallot and pulmonary stenosis than in normal individuals of the same body surface area (see Appendix Table BI). Seven patients had large "aortopulmonary" collateral arteries. In four, the collateral was a single large ductuslike vessel from the left subclavian artery or undersurface of the arch (not in the usual location of the ductus arteriosus), going to the left pulmonary artery in three patients and the pulmonary trunk at its bifurcation in one. Two of these four patients had no continuity between the pulmonary trunk and the left pulmonary artery. In a fifth

Fig. 2. Frames from biplane orthogonal right ventricular cineangiograms in patients with tetralogy of Fallot, indicating the various levels in the pathways at which the dimensions were measured. A, In patients such as this one, all diameters could be measured in a single frame. This angiogram was obtained by the anteroposterior tube in a patient sitting up 30 degrees and rotated so that the right shoulder was anterior by 15 degrees. The widely patent right ventricular infundibulum (RVl) can be measured, as can the junction between the right ventricle (RV) and the pulmonary trunk (the pulmonary "anulus", PVA). The pulmonary trunk is measured at the level of the valve commissures (PTC) and the distal pulmonary trunk (PTD). The white dots are between the right and left pulmonary arteries just beyond the bifurcation and serve as the reference point for measurement of both the origin of the left pulmonary artery (OLPA) and the origin of the right pulmonary artery (ORPA). The prebranching point (PRPA) and the midportion of the right pulmonary artery (MRPA) are labeled. Corresponding labels are given for the location of measurement for the midportion (MLPA) and prebranching (PLPA) portion of the left pulmonary artery (LPA). RPA, Right pulmonaryartery. B, The same sitting view (diastolic frame shown here), in a different patient, did not adequately delineate the proximal and midportion of the left pulmonary artery, but the prebranching point (PLPA) is seen and could be measured. The right ventricular infundibular borders (RBI) are less distinct in this patient, because of the trabecular markings. In such a patient, an additional projection was used to measure the origin and midportion of the left pulmonary artery. C, The lateral angiogram, with the patient in the same position, often served well to measure the diameter of the junction between right ventricle and pulmonary trunk (PVA). The pulmonary trunk at the level of the commissures (PTC) can be well measured in this view in this patient. The origin of the left pulmonary artery is lost in supraimposition over the right pulmonary artery (see D), but the midportion (MLPA) and the prebranching portion (PLPA) can be measured in this view. D, When the origin of the left pulmonary artery could not be measured in the usual sitting view, a "four chambered view," with the patient sitting at a 45-degree angle, the left shoulder elevated 30 degrees, and the patient turned somewhat crosstable, was often useful. This view, in the same patient as in B, served well for measurement of the narrowing at the origin of the left pulmonary artery; this area was not well seen with the standard sitting/right shoulder elevated view, nor would it have been seen with the straight anteroposterior or lateral view.

696

The Journal of Thoracic and Cardiovascular Surgery

Shimazaki et al.

Diameters (n=196)

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Fig. 3. Distribution of the dimensions (expressed as Z-values)of the right ventricularand pulmonaryarterial pathways among the 196 patients. The median Z-values among the patients are represented by the solid rectangles on the horizontal lines. The Z-valuesof the 25th and 10thpercentiles and the minimum(represented by the short hash marks) are to the left of the rectangle. The Z-values of the 75th and 90th percentiles and the maximum are to the right of the rectangle. The dimension shownfor the first-order branchesis the sum of the diametersof these branches. The Z-valuesof the dimensions in 95%of normal individuals lie within the area enclosed by the vertical dashed lines. A, Right ventricular (RV) infundibulum, right ventricular-pulmonary trunk (RV-PT) junction("anulus"), and pulmonary trunk (PT) diameters, as well as those of the right pulmonaryartery (RPA). B, Similar depiction, but with the diameters of the left pulmonaryartery (LPA) rather than the right pulmonaryartery. Note: The asterisks represent the diameters (in standard deviation units) of each individual among the seven patients with large aortapulmonarycollateralarteries. Only five asterisks are depictedfor the originof the left pulmonaryartery, as this segment was absent in two of the sevenpatients with large aortopulmonary collateralarteries. In a few other locations, fewerthan seven asterisksare depictedbecauseofmissing measurements. (Thesameinformation isinAppendix Table BI).

patient, the collateral was a large right-sided ductuslike vessel originating from the right subclavian artery and going to the right pulmonary artery. In still another individual, multiple large ductuslike vessels distributed to both upper lobe arteries. In the seventh patient, a large collateral artery originated from the infradiaphragmatic portion of the aorta and ascended paravertebrally to connect to the right pulmonary artery. These seven patients as a group had more hypoplasia of the right ventricular

outflow tract, pulmonary trunk, and right and left pulmonary arteries than did the other patients (see Fig. 3). An additional analysis was made of the relations between the actual diameters (in millimeters) of the distal pulmonary trunk and those of the right and left pulmonary arteries in patients with a narrow distal pulmonary trunk (Z-value -4 or less). This showed that the actual, nonnormalized, diameter (in millimeters) of the origin of the left pulmonary artery was smaller than that

Volume 103 Number 4 April 1992

of the pulmonary trunk in many such individuals with tetralogy of Fallot, although in terms of Z-values this was true in only a few individuals (Fig. 9). The same was true of the mid portion of the left pulmonary artery and, in a few individuals, of the prebranching area. This same situation pertained in only a few individuals in regard to the origin of the right pulmonary artery (Fig. 10).

Tetralogy and pulmonary stenosis

6

Critique of the study. The patients are probably reasonably representative of patients born with tetralogy of Fallot, since many were in the first few months of life when studied (see Fig. I) and seem optimal for a project of this type. Patients first seen for interventional treatment at an older age than that of most of the patients in this study probably comprise a select subset who have survived without interventional therapy, and they may have fewer areas of severe hypoplasia. Patients studied after having undergone some form of interventional therapy may have iatrogenic changes in their right ventricular outflow tract and pulmonary arteries, and inferences from them are probably not applicable to patients who are being considered for primary repair. Previous studies. Few if any reported studies have described in detail the dimensions of the entire pathway from the right ventricular infundibulum to and including the right and left pulmonary arterial branches in patients with surgically untreated tetralogy of Fallot and pulmonary stenosis. Such a description can be accomplished in life only by studying and measuring images of these structures, and cineangiographic images are the ones most generally available. Fragmentary observations have been made anatomically and surgically, but they have been incomplete. Histologic studies have shown the intraacinar pulmonary arteries to be narrower and thinner walled than in normal individuals.P: 13 which is a little surprising in view of the essentially normal diameters of the primary branches of the right and left pulmonary arteries in the patients in this study. A major flaw in some previous studies of dimensions of the pulmonary arteries has been the grouping together of patients with tetralogy of Fallot and pulmonary atresia and those with tetralogy and pulmonary stenosis," Currently, it is recognized that diffusely small right and left pulmonary arteries occur commonly in tetralogy and pulmonary atresia and uncommonly in tetralogy and pulmonary stenosis. Also, when pressure and flow are increased surgically in patients with tetralogy and pulmonary atresia, diffusely narrowed pulmonary arteries often enlarge in some areas and not in others, presumably because of localized noncompliant arterial wall abnormalities. These abnormalities are uncommon in patients with tetralogy and pulmonary stenosis. It has been demonstrated in patients with tetralogy and pulmonary

Larger

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Z(RV-PT Junction)

Fig. 4. Scattergram illustrating the relation between the diameters (expressed as Z-values) of the distal pulmonary trunk (PT) and the right ventricular-pulmonary trunk (RV-PT) junction ("anulus") in each of the 196 patients. Circles lying above the diagonal line of identity represent the patients in whom the distal pulmonary trunk is larger (wider) than the "anulus," and those lying below the line represent patients in whom the distal pulmonary trunk is narrower (smaller) than the "anulus." Noteworthy are the few patients with extreme narrowing of the distal pulmonary trunk, but only moderate narrowing of the anulus.

atresia that ductal tissue often extends into the wall of the left pulmonary artery, and this tissue may fibrose and result in a noncompliant wall in the proximal left pulmonary artery. 14 Because of all these differences, the present study of dimensions addressed only patients with tetralogy and pulmonary stenosis, and the inferences from the study apply only to patients with tetralogy and pulmonary stenosis. Methods of expressing the dimensions. Expressing the dimensions of the pulmonary arteries as cross-sectional area has not provided better correlations with outcome than has expressing them as diameter. Thus there is no reason to make the assumptions (circular shape) and computations required for cross-sectional area. However, as stated earlier, the cross-sectional area expressed in standard deviation units (Z-value) by the equations used in the present study has the same numeric value as does diameter, except for the branches of the left and right pulmonary arteries. No studies have demonstrated an advantage over the Z-value of using the diameter index (see Appendix Table A2), diameter expressed as percent of normal (see Appendix Table A3), the Nakata index (see Appendix Table AI), or the MeGoon ratio (see Appendix TableA4). Further, in view ofthedemonstrated variability in the dimensions at different levels along

The Journal of Thoracic and Cardiovascular

6 9 8 Shimazaki et al.

Surgery

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Fig. 5. Scattergram similar to that in Fig. 4, illustrating the relation between the diameters of the origin of the pulmonary arteries and the distal pulmonary trunk (PT). Circles lying below the diagonal line of identity represent patients in whom the diameter (expressed as Z-value) of the origin of the right or left pulmonary artery is small compared with that of the distal portion of the pulmonary trunk. A, Comparison in the case of the right pulmonary artery (RPA). In no patient was the origin of the right pulmonary artery appreciably smaller (in terms of Z-value) than the distal pulmonary trunk. B, Comparison in the case of the left pulmonary artery (LPA).

the pathway from right ventricle to pulmonary arterioles, use of methods (McGoon units, Nakata index) based solely on the dimensions at the prebranching level no longer seems advisable. Also, the finding that the descending aorta at the diaphragm is usually somewhat more narrow in patients with tetralogy than in normal individuals indicates that the McGoon ratio may be, falsely, more favorable than the Z-value.

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Z(RPA Origin)

Fig. 6. A, Scattergram, similar to Fig. 4, illustrating the relation between the diameters of the midportion and of the origin of the right pulmonary artery (RPA). Note that in most patients the midportion of the artery was wider than the origin, and in none was it appreciably more narrow. B, Scattergram of the diameters of the prebranching level of the right pulmonary artery and the origin. Note that usually the immediately prebranching levelwas widerthan the origin, but the prebranching level was more narrow in a few patients.

The availability of equations for computing the Z-value from the measured dimension and the patient's body surface area, and the widespread use in other situations of this general technique of expression, recommended its use in this study. Surgical implications of the dimensions. Narrowness

Volume 103 Number 4 April 1992

(underdevelopment, hypoplasia) of the right ventricular infundibulumand its junction with the pulmonary trunk (pulmonary valve"anulus") has long been recognized as characteristic of many patients with severe tetralogy of FaUot. Since the early demonstration of the unfavorable effect on survival of severe postrepair right ventricular hypertension,'> transannular patching has been generally used in such situations. Nonetheless, considerableelevation of the right ventricular pressure has sometimes beenpresentearly and late after repair.b 4 In the absence of pulmonary vascular disease, this indicates residual pathway narrowing at some level, despite the efforts of experienced surgeons to avoid it. The present study indicates that extreme narrowingof the right ventricular infundibulum and pulmonary valve "anulus" is usually accompanied by similar, and occasionally evengreater, narrowingofthe verydistal portion of the pulmonary trunk. In such patients a transannular (or pulmonary truncal) enlarging patch graft should be extended at least to the distal pulmonary trunk. Yet, insertion of evena rectangular patch graft eliminatesthe pressuregradient caused by a narrow area only when the patch is extended well into a wider area distally. Otherwise, onlythe componentof the high resistancerelated to the lengthof the narrowingisaffectedin a major way,and thesiteof the considerableresidualgradient causedby the small cross-sectional area is simply moveddistally. (Poiseuille-Hagen formula: (';lPjq) = c(1/1jr4) , where LiP is pressure drop, q is flow, LiP jq is resistance, 1/ represents viscosity, 1is the length, r the radius, and c the conversion factor for units and for the velocity profile factor.) This all indicatesthe dimensionalbasisof the well-recognized need to extend the enlarging transannular patch well into the left pulmonary artery unless the distal pulmonary trunk is large. However, the dimensions in some patients are such that this does not always extend the patch into a widened portion of the pathway (see Fig. 9, A), and a residual gradient can be expected,particularly with the increase in pulmonary blood flow that results from repair of the tetralogyof Fallot. Also,onlywhenthe Z-values of the diameters of the right pulmonary artery are greater than about -2 (that is, within the range of normal) can this artery be expected to carry the normal pulmonarybloodflow of the postrepair tetralogy patient withouta pressuregradient across it. These are probably the dimensional bases of residual gradients after the repair of tetralogy of Fallot, even with a well-fashioned transannular patch extended wellinto the left pulmonary artery. However, if the procedureisdonein a manner that is appropriate to the morphology, the residual gradient is known to be "acceptable" in the vast majority of patients. Relation of the dimensions to the unpredictability of the postrepair right ventricular-left ventricular pressure ratio. The analysis emphasizes the extreme vari-

Tetralogy and pulmonary stenosis

699

6

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- 16 IL...L....L.........................L.....................- L."""--.L-..,,-L.-L-.L......o-.l...--'-.L.....'-.J -16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6

Z(LPA Origin)

Fig. 7. A, Scattergram, similar to Fig. 4, illustrating the relation between the diameters of the midportion and the origin of the left pulmonary artery (LPA). Note that in most patients the origin was usually somewhat more narrow than the midportion (themidportion wider than the origin), and in one patient it was very much more narrow. Also, one patient was an exception, in that the midportion was very narrow whereas the origin had about a normal diameter. B, Scattergram of the diameters ofthe prebranching level of the left pulmonary artery and the origin. In most patients the origin was moderately narrower than the prebranching level (prebranching level larger), and in one patient the origin was extremely narrow in comparison with the prebranching level.

ability in the dimensions in patients with tetralogy of Fallot. This variability is from patient to patient and also alongthe pathwaysin many individualpatients. This isat least a partial explanation for the difficulty in predicting

The Journal oi Thoracic and Cardiovascular Surgery

700 Shimazaki et al.

6

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0

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0

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° 0

-4 -6 -10 -8 Z(Smallest Diameter)

-2

0

0

2

Fig. 8. Scattergram, showingthe relationin each individual patient between (I) the variabilityof the diameters at the various points along the pathway from the "anulus" to the first primary branch of the right pulmonaryartery (RPA) (shown in A) and of the left pulmonary artery (LPA) (shown in B) and (2) the smallestdiameter along the pathway. The variability,along the verticalaxis of the plots,is expressed as the standard deviation (SD) of the mean of all the measured diameters (expressed as Z-value) along the pathway. The larger this standard deviation, the greater the variability.The scattergram shows that the smallerthe smallestdiameter along the pathway, the greater was the variability of the diameters.

the postrepair ratio between peak pressure in the right ventricle and that in the left (PRV/LV) from limited expressions of the preoperative dimensions of the pathways, such as only at the prebranching point or at a single narrowest point. 7, 16 Even with rather complete knowledge of the pathways such as was obtained in this study, and of the changes in pulmonary blood flow resulting from the repair, only complex computations could provide reliable predictions of postrepair PRV/L v, Contrast with tetralogy of Fallot and pulmonary atresia. Only two ( 1%) of the 196 patients in this study

had nonconfluent right and left pulmonary arteries, in contrast to 16% of those with tetralogy and pulmonary atresia (P(Fisher) < 0.0001).17 No patients (0%) in the present study had incomplete arborization of the right or left pulmonary artery, in contrast to 53% of those with pulmonary atresia and confluent right and left pulmonary arteries and 85% of those with nonconfluent arteries. The median value for the McGoon ratio was 2.1 in the patients in the present study, in contrast to a value of 1.05 in patients with tetralogy with pulmonary atresia."? Although measurements were not made of the diameters

Volume 103

Number 4 April 1992

Tetralogy and pulmonary stenosis

701

1.0

16

''I 12

:? 10 C'

LPA Origin

.;:

o

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s

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8

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4

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:

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4

6

8

10

12

14

16

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oj 0; 0:

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-14

-13

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-11

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-9

-8

-7

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-5

-4

-3

Z(Distal PTJ

Fig. 9. Scattergram, showing the relation between the diameter, in millimeters, of the origin of the left pulmonary artery (LPAj and that, in millimeters, of the distal portion of the pulmonary trunk (PTj, in each individual in whom the distal pulmonary trunk was small (Z equal to or less than -4). The numbers along the vertical axis on the right hand side represent the ratio of the diameters (in millimeters) of the left pulmonary artery origin and distal pulmonary trunk. B, Scattergram, showing the same relations but with the diameters expressed as Z-values. throughout the lobar and segmental branches of the pulmonary arteries in the present study, the impression was that stenoses were not present, whereas peripheral stenoses were often identified in patients with tetralogy and pulmonary atresia. One (0.5%) of the patients in the present study had a large aortopulmonary collateral artery arising directly from the aorta, as did 65% of these with pulmonary atresia. This all suggests that the pulmonary arteries are fundamentally different in these two subsets of patients with tetralogy of Fallot. Many people in both institutions contributed greatly to these studies. We thank Dr. Frank Hanley for his reviewand critiques,

Dr. James Lock for help in the original identification of the patients, Ms. Debbie Nuby and Ms. Nancy Ferguson, who skillfully produced the text and graphics, Ms. Mary Lynne Clark and Ms. Phyllis Newsom, who performed the follow-up, and Mr. Rob Brown and Ms. Laura Young, whose assistance with the data entry and analyses was invaluable. REFERENCES 1. Lillehei CW, Cohen M, Warden HE, et al. Direct vision intracardiac surgical correction of the tetralogy of Fallot, and pulmonary atresia defects: report of first ten cases. Ann Surg 1955;142:418. 2. Kirklin JW, Blackstone EH, Kirklin JK, Pacifico AD, Aramendi J, Bargeron LM Jr. Surgical results and proto-

702

The Journal of Thoracic and Cardiovascular Surgery

Shimazaki et al.

1.0

16 14

o

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00

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-5

-8

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o

o

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l

0

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

Z(Distal PT)

Fig. 10. Scattergram as in Fig. 9, showing the relation between the diameter of the origin of the right pulmonary artery (RP A) and that of the distal portion of the pulmonary trunk (PT). A, Diameters in millimeters. B, Diameters in Z-values.

cols in the spectrum of tetralogy of Fallot. Ann Surg 1983; 198:251-65. 3. Lang P, Chipman CW, Siden H, Williams RG, Norwood WI, Castaneda AR. Early assessment of hemodynamic status after repair of tetralogy of Fallot: a comparison of 24 hour (intensive care unit) and I year postoperative data in 98 patients. Am J Cardiol 1982;50:795-9. 4. Kirklin JK, Kirklin JW, Blackstone EH, Milano A, Pacifico AD. Effect of transannular patching on outcome after repair of tetralogy of Fallot. Ann ThoracSurg 1989;48:78391.

5. BlackstoneEH, KirklinJW, Pacifico AD. Decision-making

in repair of tetralogy of Fallot based on intraoperative measurements of pulmonary arterial outflow tract. J THORAC CARDIOVASC SURG 1979;77:626-32. 6. Blackstone EH, Kirklin JW, Bertranou EG, Labrosse CJ, Soto B, Bargeron LM Jr. Preoperative prediction from cineangiograms of postrepair right ventricular pressure in tetralogy of Fallot. J THORAC CARDIOVASC SURG 1979; 78:542-52. 7. Shimazaki Y. Tetralogy of Fallot [Letter]. J THORAC CARDIOVASC SURG 1990;99:1117-20. 8. Bini M, Naftel DC, Blackstone EH. Measurements of cineangiograms of apparently normal children, in Chap. 1 in:

Volume 103 Number 4 April 1992

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10.

II.

12.

Tetralogy and pulmonary stenosis

70 3

13. Johnson RJ, Haworth SG. Pulmonary vascular and alveolar development in tetralogy of Fallot: a recommendation for early correction. Thorax 1982;37:893-901. 14. Elzenga NJ, Gittenberger-de Groot AC. The ductus arteriosus and stenoses of the pulmonary arteries in pulmonary atresia. Int J Cardiol 1986;11:195-208. 15. Kirklin JW, Ellis FH Jr, McGoon DC, DuShane JW, Swan HJC. Surgical treatment for the tetralogy of Fallot by open intracardiac repair. J THORAC CARDIOVASC SURG 1959; 37:22-46. 16. Groh MA, Meliones IN, Bove EL, et al. Repair of tetralogy of Fallot in infancy: effect of pulmonary artery size on outcome. Circulation [In press]. 17. Shirnazaki Y, Maehara T, Blackstone EH, Kirklin JW, Bargeron LM Jr. The structure of the pulmonary circulation in tetralogy of Fallot with pulmonary atresia. J THORAC CARDlOVASC SURG 1988;95:1048-58.

Kirklin JW, Barratt-Boyes BG, eds. Cardiac surgery, 2nd ed. New York: Churchill Livingstone. [In press.] Sievers H-H, Onnasch DGW, Lange PE, Bernhard A, Heintzen PH. Dimensions of the great arteries, semilunar valve roots, and right ventricular outflow tract during growth: normative angiocardiographic data. Pediatr Cardiol 1983;4:189-96. Nakata S, Yasuharu I, Takanashi Y, et al. A new method for the quantitative standardization of cross-sectional areas of the pulmonary arteries in congenital heart diseases with decreased pulmonary blood flow. J THORAC CARDlOVASC SURG 1984;88:610-9. Piehler JM, Danielson GK, McGoon DC, Wallace RB, Fulton RE, Mair DD. Management of pulmonary atresia with ventricular septal defect and hypoplastic pulmonary arteries by right ventricular outflow construction. J THORAC CARDlOVASC SURG 1980;80:522-67. Hislop A, Reid L. Structural changes in the pulmonary arteries and veins in tetralogy of Fallot. Br Heart J 1973; 35:1178.

Appendix Table AI. Tabular depiction of the dimensions (expressed as cross-sectional area index*) of the right ventricular outflow tract, pulmonary trunk, right and left pulmonary arteries, branches'[ of the right and left pulmonary arteries, and the aorta just above the diaphragm Cross-sectional area index (mm2 • m- 2) for the indicatedpercentiles Structure Infundibulum Proximal Midportion RV-PT junction C'anulus") Pulmonary trunk Commissural level Distal RPA Origin 1/20-M Midportion 1/2 M-P Prebranching Branches LPA Origin Midportion Prebranching Branches LPA + RPA:j: Aorta (diaphragm)

n

Min

5%

10%

186 180 192

13 17 9.9

40 32 32

192 193

8.0 3.0

25%

50%

75%

90%

95%

Max

47 50 45

78 85 71

120 129 107

183 186 141

255 236 194

307 267 253

447 481 382

28 38

36 48

49 66

74 101

123 144

184 214

260 293

444 520

196 194 195 194 194 187

11 12 11 11' 11 21

28 32 37 39 38 40

36 41 41 45 47 53

46 59 66 66 71 69

74 88 100 101 108 102

110 124 140 139 152 137

147 172 196 198 208 164

185 212 240 230 239 210

914 835 684 757 681 550

185 184 192 173 190 195

11 5.6 9.1 24 21 49

21 30 33 57 75 62

31 41 44 79 99 70

42 62 63 108 140 82

66 98 101 164 212 96

113 144 144 246 297 113

160 194 209 322 384 126

181 235 229 374 432 145

309 432 413 1076 793 293

Key: LPA, Left pulmonary artery; M-P, midportion to prebranching; O-M, origin to midportion; RPA, right pulmonary artery; RV-PT, right ventricle-pulmonary trunk. 'The measured diameter was converted to the cross-sectional area, assuming the structure had a circular shape in cross-section, using the equation (area = 11' r 2) . The cross-sectional area was then normalized by dividing it by body surface area. tThe value for the primary branches was the sum of the values of the individual branches. The right pulmonary artery had two primary branches in 96% of patients and tbree in 4%. The left pulmonary artery had two primary branches in 70% of patients, three in 25%, and four in 5%. :j:Nakataindex. The mean normal value of the index according to Nakata and colleagues?was 330 mm- . M- 2 and was 225 in the study of Bini, Naftel, and Blackstone" (see text).

The Journal of Thoracic and Cardiovascular Surgery

704 Shimazaki et al.

Appendix Table A2. Tabular depiction as in Appendix Table AI, with the dimensions expressed as diameters, and normalized to the body surface area Diameter index (mm . m- 2) of the indicated percentiles Structure

Infundibulum Proximal Midportion RV·PT junction ("anulus") Pulmonary trunk Commissural level Distal RPA Origin 1/20-M Midportion 1/2 M-P Prebranching Branches LPA Origin Midportion Prebranching Branches LPA+ RPA Aorta (diaphragm)

n

Min

5%

10%

25%

50%

75%

90%

95%

Max

II

12 12 13

16 15

20 22 19

26 25 22

31 28 26

37 35 30

53 41 35

186 180 192

5.3 4.6 6.2

10

192 193

4.6 5.6

9.6 10

II

12

13 15

16 18

20 23

26 28

30 32

47 49

196 194 195 194 194 187

7.1 6.5 7.1 5.9 5.8 10.1

9.2 10 11

15

10 12 12 12 13 18

12 14 15 16 16 21

16 17 18 18 19 25

20 21 21 22 23 29

24 26 26 26 27 35

28 30 30 29 30 38

46 44 47 45 45 50

185 184 192 173 190 195

5.1 4.7 7.0 13 15 8.1

9.0 9.4 11 15 22 13

9.9 12 12 17 27 14

12 15 15 20 31 16

15 18 18 24 38 18

19 22 22 29

24 26 26 33 51 25

28 29 29 38 58 29

36 43 38 70 78 44

II

II II

17

44

20

Key: LPA, Left pulmonary artery; M·P, midportion to prebranching; O-M, origin to midportion; RPA, right pulmonary artery; RV-PT, right ventricle-pulmo-

nary trunk.

Appendix Table A3. Tabular depiction as in Table AI, with the dimensions expressed as diameters, and normalized by dividing the value by the mean value in a normal individual of the same body surface area, obtained from the equations of Bini,8 Sievers/ and their colleagues Percent of normal diameter for the indicated percentiles Structure

Infundibulum Proximal Midportion RV-PT junction C'anulus'') Pulmonary trunk Commissural level Distal RPA Origin 1/20-M Midportion 1/2 M-P Prebranching Branches LPA Origin Midportion Prebranching Branches LPA+ RPA Aorta (diaphragm)

n

Min

5%

10%

25%

172 166 192

19 22 19

34 35 36

37 39 46

192 193

18 10

31 36

196 194 195 194 194 187

30 35 33 32 27 48

185 184 192 173 195 166

28 23 31 51 63 29

50%

75%

90%

95%

Max

47 48 55

60 61 66

73 74 78

90 83 91

102 96 99

138 128 127

35 41

41 48

49 57

63 70

79 87

89 98

120 144

44 57 59 60 51 65

50 62 64 67 56 74

57 73 78 78 68 85

70 86 93 93 81 100

86 103 108 110 99 116

104 126 130 132 113 132

113 142 147 140 123 141

234 253 229 241 197 229

44 52 53 66 70 54

52 63 65 70 74 62

63 78 77 88 80 72

78 91 92 101 87 85

98 110 110 121 95 99

116 129 132 141 101 112

134 143 142 160 106 121

170 204 184 277 150 166

Key: LPA, Left pulmonary artery; M-P, midportion to prebranching; O-M, origin to midportion; RPA, right pulmonary artery; RV·PT, right ventricle-pul-

monary trunk.

Volume 103 Number 4 April 1992

Tetralogy and pulmonary stenosis

705

Appendix Table A4. Dimensions of the prebranching portions of the right and the left pulmonary arteries, expressed as a ratio obtained by dividing the diameter(s) by the diameter of the descending thoracic aorta at the diaphragm Ratio for the indicated percentiles Structure

n

Min

5%

/0%

25%

50%

75%

90%

95%

Max

RPA LPA LPA+RPA*

193 191 165

0.34 0.36 0.75

0.61 0.57

0.71 0.64 1.4

0.86 0.84 1.8

1.0 1.0 2.1

1.3

1.2 2.4

1.5 1.5 2.7

1.7 1.6 3.1

2.4 2.1 4.1

1.2

Key: LPA, Left pulmonary artery; RPA, right pulmonary artery.

'McGoon ratio.

Appendix Table Bl. Tabular depiction as in Appendix A-I, with the dimensions expressed as the Z-value of the diameter; the Z-value is the same for the cross-sectional area, except in the case of the branches (see text) Z-values for the indicated percentiles Structure Infundibulum Proximal Midportion RV-PT junction ("anulus") Pulmonary Trunk Commissural level Distlll RPA Origin 1/20-M Midportion 1/2 M-P Prebranching Branches* LPA Origin Midportion Prebranching Branchest LPA+RPA Aorta (diaphragm)

n

Min -15

5%

10%

25%

50%

75%

90%

95%

Max

-8.8 -8.3 -6.1

-6.7 -6.4 -4.4

-4.4 -4.4 -3.2

-2.7 -2.6 -1.8

-0.8 -1.7 -0.7

0.2 -0.4 -0.1

2.4 1.9 1.7

172 166 192

-12

-9.5 -9.2 -7.2

192 193

-11 -14

-7.8 -6.9

-6.8 -5.8

-5.9 -4.9

-4.7 -3.8

-2.9 -2.3

-1.7 -1.0

-0.8 -0.1

1.2 2.7

0.8 2.2 2.3 2.1 1.4 3.0

5.6 5.7 5.1 5.4 4.8 7.2

-13

196 194 195 194 194 187

-8.0 -6.4 -6.7 -7.0 -9.2 -6.4

-5.5 -3.5 -3.2 -3.2 -4.8 -3.8

-4.5 -2.9 -2.7 -2.4 -4.2 -2.6

-3.7 -1.9 -1.5 -1.5 -2.7 -1.4

-2.4 -0.9 -0.4 -0.4 -1.5 0.0

-1.0 0.2 0.5 0.6 -0.1 1.3

0.2 1.4 1.6 1.7 0.9 2.4

185 184 192 173 166 195

-8.5 -8.9 -7.1 -3.1 -9.3 -3.0

-5.5 -3.8 -3.8 -2.0 -4.7 -2.2

-4.4 -2.7 -2.6 -1.6 -3.6 -2.0

-3.2 -1.5 -1.5 -0.6 -2.4 -1.4

-1.5 -0.5 -0.5 0.0 -1.2 -0.9

-0.1 0.6 0.6 0.9 -0.1 -0.3

1.0 1.6 1.6 1.6 0.9 0.1

2.0 2.2 2.1 2.2 1.4 0.4

3.6 4.3 3.7 4.8 3.9 2.6

*Branches (cross-sectional area)

187

-6.1

-3.2

-2.3

-1.5

0.0

l.l

2.0

2.9

6.4

tBranches (cross-sectional area)

173

-3.0

-0.5

-0.3

0.9

1.9

2.8

3.7

4.5

7.8

Key: LPA, Left pulmonary artery; M-P, midportion to prebranching; O-M, originto midportion; RPA, right pulmonary artery; RV-PT, right ventricle-pulmonary trunk.