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Balloon valvuloplasty in children with dysplastic pulmonary valves
August
fore. On Z-dimensional and Doppler echocardiography 2 days later there was no mitral regurgitation and normal mitral apparatus. The patient had no symptoms during 2 months follow-up after dilatation, but dyspnea developed in the third month. Dilatation of a subvalvular membrane is clearly different from valvuloplasty of a stenotic, deformed and often calcified aortic valve. In contrast to the calcified aortic valve found in older adults, the membrane may be relatively elastic, stretching rather than fracturing. There are no commissures in the dense, fibrous membrane,3 so no natural planes are present to facilitate splitting. Also, the outflow tract is not surrounded by a rigid anulus, and is therefore distensible. Since balloons no greater than 20 mm in diameter were available, the result may have also been,limited by balloon size. As in dilatation of the aortic valve itself, there is often persistence of moderate gradients with current techniques and equipment.4 Surgical treatment of DSS is advocated not only for reduction of the pressure gradient, but also to prevent damage to the aortic valve from turbulent systolic blood flow. Balloon dilatation in children reduces aortic regurgitation in some cases,Q as it did in this patient; yet postdilatation pressure tracings continued to show high-frequency systolic vibrations sirggesting high-velocity, turbulent blood flow through the left ventricular outflow tract (Fig. 5). Residual pressure gradients ranging between 30 and 60 mm Hg may follow surgery for DSS, prompting removal of myocardiurn as well as the membrane from the outflow tract.5 In this patient a residual gradient may indicate persistent
Balloon Valvuloplasty in Children with Dysplastic Pulmonary Valves THOMAS G. DISESSA, MD BRUCE S. ALPERT, MD NANCY A. CHASE, MD STUART E. BIRNBAUM, MD DONALD C. WATSON, MD
P
ercutaneous balloon valvuloplasty for congenital pulmonary valvar stenosis (PS) is a safe and effective method for relief of obstruction.1-3 Previous reports deal primarily with the classic form of PS. The characteristics of classic PS at surgery or necropsy include thickening of the cusps combined with commissural fusion.4 The dysplastic valve, in contrast, is characterized by stenosis without fusion of its cusps. Obstruction From the Division of Cardiology, Department of Pediatrics, and the Division of Cardiothoracic Surgery, Department of Surgery, University of Tennessee, Memphis, Tennessee. Manuscript received October 14, 1986; revised manuscript received February 24,1987, accepted February 25,1987.
1, 1987
THE
AMERICAN
JOURNAL
OF CARDIOLOGY
Volume
60
405
hemodynamic consequences of the subvalvular membrane. High-fidelity pressure recordings continued to show late peaking and vibrations of the left ventricular systolic pressure waveform typical of outflow tract obstruction. As in valvular stenosis, DSS may be complicated by secondary obstruction due to left ventricular bypertrophy.6 An element of dynamic obstruction is thus a concern. Initial reports of dilatation of DSS in children indicate success with discrete membranes, and not in patients with a muscular band.2 Surgical treatment of membranous subvalvular stenosis in adults is established and has long-term follow-up; thus, balloon dilatation for DSS remains an experimental therapy requiring further evaluation. Acknowledgment: We thank Petrit Alibali, Lynn Weinert, and Roberto Lang, MD, for help preparing the figures. 1. deLezo JS, Pan M, Sancho M, Herrera N, Arizon J, Franc0 M, Concha M, Valles F, Romanos A. Percutaneous transluminal balloon dilatation for discrete subaortic stenosis. Am T Cardiol 1986:58xX9-821. 2. Lababidi Z, Weinhaus L, Stceckle H, Walls JT. Transluminal balloon dilatation for discrete subaortic stenosis. Am [ Cardiol 1987;59:423-425. 3. Roberts WC. Congenital cardiovascular abnormalities usually “silent” until adulthood; morphologic features of the floppy mitral valve, vafvular oortic stenosis, discrete subvalvular aortic stenosis, hypertrophic cardiomyopathy. sinus of Valsalva aneurysm, and the Marfan syndrome. In: Roberts WC, ed. Congenital Heart Disease in Adults. Philadelphia: FA Davis, 1979:426-429. 4. McKay RG, Safian RD, Lock JE, Mandell VS, Thurer RL, Schnitt SJ, Grossman W. Balloon dilatation of calcific aortic stenosis in elder19 patients; postmortem. intraoperative, and percutaneous valvuloplasty studies. Circulation 1986;74:119-125. 5. Brown J, Stevens L, Lynch L, Caldwell R, Girod D, Hurwitz R, Mahoney L, King H. Surgery for discrete subvalvufar aortic stenosis: actuarial survival. Hemodynamic rest&s, and acquired oortic regurgitation. Ann Thorac Surg 1985;40:151-155. 6. Sung CS, Price EC, Cooley DA. Discrete subaortic stenosis in adults. Am / Cardiol 1978;42:283-290.
is a result of immobile cusps that consist of fibrous tissue.5 We report use of balloon valvuloplasty in 3 children with a dysplastic pulmonary valve. Between Ianuary 1985 and September 1986, 13 children with clinical, electrocardiographic, echocardiographic and Doppler evidence of moderate to severe PS underwent cardiac catheterization and balloon pulmonary valvuloplasty. Of these, 3 had features typical of Noonan’s syndrome and a dysplastic pulmonary valve. For comparison, the 10 children with classic PS are included in this report. Children with a dysplastic pulmonary valve were comparable to the patients with classic PS in age and body surface area. All children with a right ventricular pressure of at least 50% of systemic pressure or with a transvalvar peak systolic pressure gradient above 40 mm Hg underwent valvuloplasty using a standard protocol. Meperidine, 2 mg/kg, chlorpromazine, 1 mg/kg, and promethazine, 1 mg/kg, were used as premeditation. After percutaneous insertion of catheters, simultaneous pressures were recorded in the main pulmonary artery, femoral artery and right ventricle-A right ventricular cineangiocardiogram was then recorded in the anteroposterior and lateral projections. Pulmonary valve anular diameter was calculated from the
406
BRIEF
REPORTS
TABLE
I
Patient
Data Anular
PI
Age (mo)
BSA Cm*)
1 2 3
24 60 9
0.61 0.78 0.34
RV Pressure
PV Gradient
(mm W
(mm Hg)
Diameter (cm)
Pm
Post
Pre
Post
Measured
Mean Predicted*
8015 7916 129/10
8015 10815 15619
65 63 110
65 83 122
1.4 1.5 0.8
1.3 1.4 1.0
*Based on Data of Rowlatt, Rimoldi and Lev.@ BSA = body surface area; PA = pulmonary artery; pulmonary valve; RV = right ventricular.
Pre = before
valvuloplasty;
Post
PA Above Sinotubular Junction Diameter
= after
Balloon Size
(cm)
(cm)
0.9 1.0 0.8
1.5 1.8 1.2
valvuloplasty;
PV =
lateral angiocardiogram. Valvuloplasty was accomplished according to a previously described technique.l In brief, an 0.038-inch exchange wire was positioned in the left pulmonary artery. A 9Fr balloon valvuloplasty catheter (Meditech) was advanced over the wire and positioned across the pulmonary valve. The balloon was inflated to 3.5 to 5 atm pressure or until the loss of the valve “waist” was observed. After valvuloplasty, hemodynamic measurements were repeated. We retrospectively analyzed the angiocardiograms of all patients. Images were qualitatively assessed for redundance, mobility and thickness of the pulmonary
valve. Moreover, the diameter of the pulmonary trunk just above the sinotubular junction was measured (Fig. I and 2). A Student paired t test was used to compare groups and compare variables within each group. Before valvuloplasty, all children with classic valvar stenosis had moderate to severe obstruction, with a transvalvar peak systolic pressure difference of 54 f 19 mm Hg. In this group of children there was a 40% reduction (p 50.001) in right ventricular peak systolic pressure and a 56% reduction (p 50.001) in transvalvar peak systolic gradient. A11 but I child had a pulmonary valve peak systolic gradient <30 mm Hg after valvuloplasty.
FIGURE 1. Lateral right ventricular (RV) tine frame from a patient with a classic domed stenotic pulmonary valve (PV). There is poststenotic dilatation of the main pulmonary artery. a = anular diameter; b = pulmonary artery diameter above the sinotubular junction.
FIGURE 2. Lateral right ventricular (RV) tine frame from a patient with a dysplastic pulmonary valve (PV). The valve is thick and nodular. The main pulmonary artery above the sinotubular junction is underdeveloped. a = anular diameter; b = pulmonary artery diameter above the sinotubular junction.
August
Prevalvuloplasty right ventricular peak systolic pressure (97 f 23 mm Hg) and pulmonary artery to right ventricular peak systolic pressure difference (76 f 24 mm Hg) were somewhat greater in the group of children with a dysplastic valve (Table I). However, these differences were not statistically significant. Despite use of balloons with diameters greater than anular diameter, the dysplastic valve failed to produce an indentation on the inflated valvuloplasty balloon. in 2 patients, balloon diameter was 20% to 30% larger than the anular diameter. In these 3 children, the average balloon size was 17% larger than the anular diameter and 55% larger than the pulmonary trunk diameter. Balloon valvuloplasty did not produce a significant reduction in either right ventricular peak systolic pressure or transvalvar peak systolic gradient. In general, both right ventricular peak systolic pressure and pulmonary valve peak systolic pressure difference were increased after valvuloplasty (Table I). The pulmonary valve anulus in the children with a classically domed valve was 1.4 f 0.23 cm. Compared with anular diameter, the diameter of the pulmonary artery above the sinotubular junction (1.65 f 0.24 cm] was larger in each patient. In contrast, pulmonary artery diameter (0.9 f 0.08) was no larger than the anular diameter (1.2 f 0.3 cm) in each of the children with a dysplastic valve. When both groups were compared, the main pulmonary artery diameter was smaller in the children with a dysplastic valve than in those with classic PS (p 50.004). Anular diameter tended to be smaller in the dysplastic group, but the difference was not significant. However, compared to a mean predicted normal for body surface area, pulmonary valve anulus in the dysplastic group was not unusually small (Table I]. Compared to the usual domed stenotic pulmonary valve, the dysplastic valve appeared thicker and more redundant on angiography. In children with typical PS, the pulmonary trunk distal to the sinotubular junction exhibited varying degrees of poststenotic dilation (Fig. 1). In contrast, the main pulmonary artery was diffusely underdeveloped in children with a dysplastic valve (Fig. 2). All children with a dysplastic pulmonary valve underwent surgical relief of PS. The interval between valvuloplasty and surgery was 1 day to 4 months. In the child who waited 4 months for operation, there was no reduction in pulmonary valve Doppler-determined gradient. At operation, the dysplastic valves were nodular and myxomatous (“padlike fibrous tissue within the valve CUSP”~]. There was no commissural fusion. The pulmonary artery above the valve was not dilated. There was no apparent change within the pulmonary valve resulting from the valvuloplasty procedure.
I, 1987
THE
AMERICAN
JOURNAL
OF CARDIOLOGY
Volume
60
407
Kan et al2 reported the results of balloon valvuloplasty in 1 patient with a dysplastic pulmonary valve. In that patient, balloon valvuloplasty produced an immediate decrease in right ventricular systolic pressure from 78% to 54% of systemic pressure. This reduction, however, was not permanent, and on subsequent catheterization, right ventricular pressure returned to the previous level. A second valvuloplasty procedure produced a similar initial reduction in pressure, which returned to previous levels on subsequent catheterization. Radtke et al3 reported a patient with a dysplastic valve who had significant obstruction remaining after valvuloplasty. In our 3 patients with a dysplastic pulmonary valve, there was not significant reduction in either right ventricular peak systolic pressure or transvalvar peak systolic pressure difference. Several mechanisms may contribute to balloon valvuloplasty failure in children with a dysplastic valve. These include a small anulus, hypoplasia of the pulmonary trunk, commissural fusion and obstruction due to a thickened nonmobile valve. Kan et a12 commented on the “absence of post stenotic dilatation” in their patient with a dysplastic valve. We have shown that children with a dysplastic valve have a smaller pulmonary trunk than children with the usual, domed valve. When the valve is dysplastic, the main pulmonary artery is smaller than the near-normal valve anulus. Thus, we speculate that’if valve obstruction could be relieved by valvuloplasty, the pulmonary trunk would continue to obstruct flow. On cineangiography, the dysplastic valve is thick, nodular and redundant. This characteristic appearance is a reflection of the myxomatous tissue seen at surgery.5 This myxomatous tissue contributes to the immobility of the valve. Thus, the dysplastic valve is obstructive in the absence of commissural fusion. We conclude that balloon valvuloplasty is not effective in the patient with a dysplastic pulmonary valve. The causes for valvuloplasty failure include not only the abnormal valve morphologic characteristics, but also a hypoplasia of the main pulmonary artery in the presence of a near-normal sized valve anulus. 1. Rocchini AP, Kveselis DA, Crowley D, Dick M, Rosenthal A. Percutaneous balloon vafvuJoplosty for treatment of congenital pulmonary vavular stenosis in children. /ACC 1984;3:1005-1012. 2. Kan JS, White RI, Mitchell SE, Anderson JH, Gardner TJ. Percutaneous transluminal balloon valvuloplasty for pulmonary valve stenosis. Circulation 19t34;t?9:554-560. 3. Radtke W, Keane JF, Fellows KE, Lang P, Lock JE. Percutaneous balloon valvotomv of congenital oulmonarv stenosis usine oversized balloons. TACC 2986;8:9&-915.
”
’
4. Edwards JE. Pulmonary stenosis with intact ventricular septum. In: Gould SE, ed. Pathology of the Heart. 2nd ed. Springfield, IL: Charles C Thomas, 1960:391-397. 5. Koretzky ED, Moller JH, Kerns ME, Schwartz CJ, Edwards JE. Congenital pulmonary stenosis resulting from dysplasia of valve. Circulation 1969;40:4353.
6. Rowlatt UF, Rimoldi HJ, Lev M. The quantiotive anatomy child’s heart. Pediatr CJin North Am 1963;20:499-588.
of the normal
fore. On Z-dimensional and Doppler echocardiography 2 days later there was no mitral regurgitation and normal mitral apparatus. The patient had no symptoms during 2 months follow-up after dilatation, but dyspnea developed in the third month. Dilatation of a subvalvular membrane is clearly different from valvuloplasty of a stenotic, deformed and often calcified aortic valve. In contrast to the calcified aortic valve found in older adults, the membrane may be relatively elastic, stretching rather than fracturing. There are no commissures in the dense, fibrous membrane,3 so no natural planes are present to facilitate splitting. Also, the outflow tract is not surrounded by a rigid anulus, and is therefore distensible. Since balloons no greater than 20 mm in diameter were available, the result may have also been,limited by balloon size. As in dilatation of the aortic valve itself, there is often persistence of moderate gradients with current techniques and equipment.4 Surgical treatment of DSS is advocated not only for reduction of the pressure gradient, but also to prevent damage to the aortic valve from turbulent systolic blood flow. Balloon dilatation in children reduces aortic regurgitation in some cases,Q as it did in this patient; yet postdilatation pressure tracings continued to show high-frequency systolic vibrations sirggesting high-velocity, turbulent blood flow through the left ventricular outflow tract (Fig. 5). Residual pressure gradients ranging between 30 and 60 mm Hg may follow surgery for DSS, prompting removal of myocardiurn as well as the membrane from the outflow tract.5 In this patient a residual gradient may indicate persistent
Balloon Valvuloplasty in Children with Dysplastic Pulmonary Valves THOMAS G. DISESSA, MD BRUCE S. ALPERT, MD NANCY A. CHASE, MD STUART E. BIRNBAUM, MD DONALD C. WATSON, MD
P
ercutaneous balloon valvuloplasty for congenital pulmonary valvar stenosis (PS) is a safe and effective method for relief of obstruction.1-3 Previous reports deal primarily with the classic form of PS. The characteristics of classic PS at surgery or necropsy include thickening of the cusps combined with commissural fusion.4 The dysplastic valve, in contrast, is characterized by stenosis without fusion of its cusps. Obstruction From the Division of Cardiology, Department of Pediatrics, and the Division of Cardiothoracic Surgery, Department of Surgery, University of Tennessee, Memphis, Tennessee. Manuscript received October 14, 1986; revised manuscript received February 24,1987, accepted February 25,1987.
1, 1987
THE
AMERICAN
JOURNAL
OF CARDIOLOGY
Volume
60
405
hemodynamic consequences of the subvalvular membrane. High-fidelity pressure recordings continued to show late peaking and vibrations of the left ventricular systolic pressure waveform typical of outflow tract obstruction. As in valvular stenosis, DSS may be complicated by secondary obstruction due to left ventricular bypertrophy.6 An element of dynamic obstruction is thus a concern. Initial reports of dilatation of DSS in children indicate success with discrete membranes, and not in patients with a muscular band.2 Surgical treatment of membranous subvalvular stenosis in adults is established and has long-term follow-up; thus, balloon dilatation for DSS remains an experimental therapy requiring further evaluation. Acknowledgment: We thank Petrit Alibali, Lynn Weinert, and Roberto Lang, MD, for help preparing the figures. 1. deLezo JS, Pan M, Sancho M, Herrera N, Arizon J, Franc0 M, Concha M, Valles F, Romanos A. Percutaneous transluminal balloon dilatation for discrete subaortic stenosis. Am T Cardiol 1986:58xX9-821. 2. Lababidi Z, Weinhaus L, Stceckle H, Walls JT. Transluminal balloon dilatation for discrete subaortic stenosis. Am [ Cardiol 1987;59:423-425. 3. Roberts WC. Congenital cardiovascular abnormalities usually “silent” until adulthood; morphologic features of the floppy mitral valve, vafvular oortic stenosis, discrete subvalvular aortic stenosis, hypertrophic cardiomyopathy. sinus of Valsalva aneurysm, and the Marfan syndrome. In: Roberts WC, ed. Congenital Heart Disease in Adults. Philadelphia: FA Davis, 1979:426-429. 4. McKay RG, Safian RD, Lock JE, Mandell VS, Thurer RL, Schnitt SJ, Grossman W. Balloon dilatation of calcific aortic stenosis in elder19 patients; postmortem. intraoperative, and percutaneous valvuloplasty studies. Circulation 1986;74:119-125. 5. Brown J, Stevens L, Lynch L, Caldwell R, Girod D, Hurwitz R, Mahoney L, King H. Surgery for discrete subvalvufar aortic stenosis: actuarial survival. Hemodynamic rest&s, and acquired oortic regurgitation. Ann Thorac Surg 1985;40:151-155. 6. Sung CS, Price EC, Cooley DA. Discrete subaortic stenosis in adults. Am / Cardiol 1978;42:283-290.
is a result of immobile cusps that consist of fibrous tissue.5 We report use of balloon valvuloplasty in 3 children with a dysplastic pulmonary valve. Between Ianuary 1985 and September 1986, 13 children with clinical, electrocardiographic, echocardiographic and Doppler evidence of moderate to severe PS underwent cardiac catheterization and balloon pulmonary valvuloplasty. Of these, 3 had features typical of Noonan’s syndrome and a dysplastic pulmonary valve. For comparison, the 10 children with classic PS are included in this report. Children with a dysplastic pulmonary valve were comparable to the patients with classic PS in age and body surface area. All children with a right ventricular pressure of at least 50% of systemic pressure or with a transvalvar peak systolic pressure gradient above 40 mm Hg underwent valvuloplasty using a standard protocol. Meperidine, 2 mg/kg, chlorpromazine, 1 mg/kg, and promethazine, 1 mg/kg, were used as premeditation. After percutaneous insertion of catheters, simultaneous pressures were recorded in the main pulmonary artery, femoral artery and right ventricle-A right ventricular cineangiocardiogram was then recorded in the anteroposterior and lateral projections. Pulmonary valve anular diameter was calculated from the
406
BRIEF
REPORTS
TABLE
I
Patient
Data Anular
PI
Age (mo)
BSA Cm*)
1 2 3
24 60 9
0.61 0.78 0.34
RV Pressure
PV Gradient
(mm W
(mm Hg)
Diameter (cm)
Pm
Post
Pre
Post
Measured
Mean Predicted*
8015 7916 129/10
8015 10815 15619
65 63 110
65 83 122
1.4 1.5 0.8
1.3 1.4 1.0
*Based on Data of Rowlatt, Rimoldi and Lev.@ BSA = body surface area; PA = pulmonary artery; pulmonary valve; RV = right ventricular.
Pre = before
valvuloplasty;
Post
PA Above Sinotubular Junction Diameter
= after
Balloon Size
(cm)
(cm)
0.9 1.0 0.8
1.5 1.8 1.2
valvuloplasty;
PV =
lateral angiocardiogram. Valvuloplasty was accomplished according to a previously described technique.l In brief, an 0.038-inch exchange wire was positioned in the left pulmonary artery. A 9Fr balloon valvuloplasty catheter (Meditech) was advanced over the wire and positioned across the pulmonary valve. The balloon was inflated to 3.5 to 5 atm pressure or until the loss of the valve “waist” was observed. After valvuloplasty, hemodynamic measurements were repeated. We retrospectively analyzed the angiocardiograms of all patients. Images were qualitatively assessed for redundance, mobility and thickness of the pulmonary
valve. Moreover, the diameter of the pulmonary trunk just above the sinotubular junction was measured (Fig. I and 2). A Student paired t test was used to compare groups and compare variables within each group. Before valvuloplasty, all children with classic valvar stenosis had moderate to severe obstruction, with a transvalvar peak systolic pressure difference of 54 f 19 mm Hg. In this group of children there was a 40% reduction (p 50.001) in right ventricular peak systolic pressure and a 56% reduction (p 50.001) in transvalvar peak systolic gradient. A11 but I child had a pulmonary valve peak systolic gradient <30 mm Hg after valvuloplasty.
FIGURE 1. Lateral right ventricular (RV) tine frame from a patient with a classic domed stenotic pulmonary valve (PV). There is poststenotic dilatation of the main pulmonary artery. a = anular diameter; b = pulmonary artery diameter above the sinotubular junction.
FIGURE 2. Lateral right ventricular (RV) tine frame from a patient with a dysplastic pulmonary valve (PV). The valve is thick and nodular. The main pulmonary artery above the sinotubular junction is underdeveloped. a = anular diameter; b = pulmonary artery diameter above the sinotubular junction.
August
Prevalvuloplasty right ventricular peak systolic pressure (97 f 23 mm Hg) and pulmonary artery to right ventricular peak systolic pressure difference (76 f 24 mm Hg) were somewhat greater in the group of children with a dysplastic valve (Table I). However, these differences were not statistically significant. Despite use of balloons with diameters greater than anular diameter, the dysplastic valve failed to produce an indentation on the inflated valvuloplasty balloon. in 2 patients, balloon diameter was 20% to 30% larger than the anular diameter. In these 3 children, the average balloon size was 17% larger than the anular diameter and 55% larger than the pulmonary trunk diameter. Balloon valvuloplasty did not produce a significant reduction in either right ventricular peak systolic pressure or transvalvar peak systolic gradient. In general, both right ventricular peak systolic pressure and pulmonary valve peak systolic pressure difference were increased after valvuloplasty (Table I). The pulmonary valve anulus in the children with a classically domed valve was 1.4 f 0.23 cm. Compared with anular diameter, the diameter of the pulmonary artery above the sinotubular junction (1.65 f 0.24 cm] was larger in each patient. In contrast, pulmonary artery diameter (0.9 f 0.08) was no larger than the anular diameter (1.2 f 0.3 cm) in each of the children with a dysplastic valve. When both groups were compared, the main pulmonary artery diameter was smaller in the children with a dysplastic valve than in those with classic PS (p 50.004). Anular diameter tended to be smaller in the dysplastic group, but the difference was not significant. However, compared to a mean predicted normal for body surface area, pulmonary valve anulus in the dysplastic group was not unusually small (Table I]. Compared to the usual domed stenotic pulmonary valve, the dysplastic valve appeared thicker and more redundant on angiography. In children with typical PS, the pulmonary trunk distal to the sinotubular junction exhibited varying degrees of poststenotic dilation (Fig. 1). In contrast, the main pulmonary artery was diffusely underdeveloped in children with a dysplastic valve (Fig. 2). All children with a dysplastic pulmonary valve underwent surgical relief of PS. The interval between valvuloplasty and surgery was 1 day to 4 months. In the child who waited 4 months for operation, there was no reduction in pulmonary valve Doppler-determined gradient. At operation, the dysplastic valves were nodular and myxomatous (“padlike fibrous tissue within the valve CUSP”~]. There was no commissural fusion. The pulmonary artery above the valve was not dilated. There was no apparent change within the pulmonary valve resulting from the valvuloplasty procedure.
I, 1987
THE
AMERICAN
JOURNAL
OF CARDIOLOGY
Volume
60
407
Kan et al2 reported the results of balloon valvuloplasty in 1 patient with a dysplastic pulmonary valve. In that patient, balloon valvuloplasty produced an immediate decrease in right ventricular systolic pressure from 78% to 54% of systemic pressure. This reduction, however, was not permanent, and on subsequent catheterization, right ventricular pressure returned to the previous level. A second valvuloplasty procedure produced a similar initial reduction in pressure, which returned to previous levels on subsequent catheterization. Radtke et al3 reported a patient with a dysplastic valve who had significant obstruction remaining after valvuloplasty. In our 3 patients with a dysplastic pulmonary valve, there was not significant reduction in either right ventricular peak systolic pressure or transvalvar peak systolic pressure difference. Several mechanisms may contribute to balloon valvuloplasty failure in children with a dysplastic valve. These include a small anulus, hypoplasia of the pulmonary trunk, commissural fusion and obstruction due to a thickened nonmobile valve. Kan et a12 commented on the “absence of post stenotic dilatation” in their patient with a dysplastic valve. We have shown that children with a dysplastic valve have a smaller pulmonary trunk than children with the usual, domed valve. When the valve is dysplastic, the main pulmonary artery is smaller than the near-normal valve anulus. Thus, we speculate that’if valve obstruction could be relieved by valvuloplasty, the pulmonary trunk would continue to obstruct flow. On cineangiography, the dysplastic valve is thick, nodular and redundant. This characteristic appearance is a reflection of the myxomatous tissue seen at surgery.5 This myxomatous tissue contributes to the immobility of the valve. Thus, the dysplastic valve is obstructive in the absence of commissural fusion. We conclude that balloon valvuloplasty is not effective in the patient with a dysplastic pulmonary valve. The causes for valvuloplasty failure include not only the abnormal valve morphologic characteristics, but also a hypoplasia of the main pulmonary artery in the presence of a near-normal sized valve anulus. 1. Rocchini AP, Kveselis DA, Crowley D, Dick M, Rosenthal A. Percutaneous balloon vafvuJoplosty for treatment of congenital pulmonary vavular stenosis in children. /ACC 1984;3:1005-1012. 2. Kan JS, White RI, Mitchell SE, Anderson JH, Gardner TJ. Percutaneous transluminal balloon valvuloplasty for pulmonary valve stenosis. Circulation 19t34;t?9:554-560. 3. Radtke W, Keane JF, Fellows KE, Lang P, Lock JE. Percutaneous balloon valvotomv of congenital oulmonarv stenosis usine oversized balloons. TACC 2986;8:9&-915.
”
’
4. Edwards JE. Pulmonary stenosis with intact ventricular septum. In: Gould SE, ed. Pathology of the Heart. 2nd ed. Springfield, IL: Charles C Thomas, 1960:391-397. 5. Koretzky ED, Moller JH, Kerns ME, Schwartz CJ, Edwards JE. Congenital pulmonary stenosis resulting from dysplasia of valve. Circulation 1969;40:4353.
6. Rowlatt UF, Rimoldi HJ, Lev M. The quantiotive anatomy child’s heart. Pediatr CJin North Am 1963;20:499-588.
of the normal