Echocardiographic Assessment of Neonates With Pulmonary Atresia and Intact Ventricular Septum

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1 JA Vol 12, No, chocardiographic Assessment of Neonates With Pulmonary Atresia and Intact Ventricular Septum MAURI P LUNG, MB BS, MRP, * R-KUNG MOK, MB BS, FRS, PING-WAI RUI, PHD Aberdeen, Hong Kong In this prospective study, 27 consecutive neonates suspected to be suffering from pulmonary atresia and intact ventricular septum underwent detailed two-dimensional echocardiographic examination before cardiac catheterization Of the 27 neonates 25 had pulmonary atresia and intact ventricular septum and the remaining 2 had "functional pulmonary atresia" secondary to severe bstein's anomaly of the tricuspid valve In all 25 neonates with pulmonary atresia and intact ventricular septum, the diagnosis and right ventricular morphology based on the tripartite approach were correctly established by echocardiography The associated bstein's anomaly in two babies with pulmonary atresia and intact ventricular septum was also correctly identified by echocardiography Among the five babies who had a sinusoidal-coronary artery communication, echocardiography demonstrated the fistula in one and provided clues for its diagnosis in two others In the 25 neonates with pulmonary atresia and intact ventricular septum, the echocardiographic dimensions of their tricuspid anulus, right ventricular infundibulum and main pulmonary artery correlated well with the angiocardiographic measurements (r > 8) The results of this study suggest that, in the management of neonates with pulmonary atresia and intact ventricular septum, preoperative evaluation by echocardiography is usually sufficient and cardiac catheterization should be reserved for selected cases (J Am oli ardioi1988;12:719-25) In the management of pulmonary atresia with intact ventricular septum, the morphology of the right ventricle and tricuspid valve and the dimensions of the tricuspid anulus, right ventricular infundibulum and main pulmonary artery as well as the presence of sinusoidal-coronary artery communications may influence the choice of surgical approach and prognosis -5) The present study is an attempt to determine whether two-dimensional echocardiography is comparable with angiocardiography in defining the detailed anatomy of the right side of the heart in neonates with pulmonary atresia and intact ventricular septum Methods chocardiography Twenty-seven consecutive neonates with suspected pulmonary atresia and intact ventricular septum were studied between January 1982 and June 1987 From the Departments of 'Paediatrics and Surgery, University of Hong Kong, Grantham Hospital, Hong Kong, Manuscript received November 16, 1987; revised manuscript received April 6, 1988, accepted April 2, 1988 Address for reprints: K Mok, The Grantham Hospital, 125 Wong huk Hang Road, Aberdeen, Hong Kong 1988 by the American ollege of ardiology Two-dimensional echocardiography was performed with the Advanced Technology Laboratory (Mark V series 3) mechanical scanner fitted with a 5 or 75 MHz transducer All echocardiograms were recorded on videotapes for detailed analysis With the use of the sequential segmental approach (6), the atrial arrangement and intracardiac and extracardiac anatomy were delineated by the standard echocardiographic views and the diagnosis was established The right ventricular morphology based on the tripartite approach of Goor and Lillehei (7) and Bull et al (8) was then studied by a combination of echocardiographic views: the inlet was examined by the apical four chamber view, the trabecular portion beyond the tricuspid valve insertion by the subcostal four chamber view with anterior angulation of the transducer and the outlet (infundibulum) by the high precordial shortaxis view A search was then made for bstein's anomaly and restrictive movement of the tricuspid valve and for sinusoids within the thickened right ventricular myocardium The anatomy of the proximal coronary arteries was defined from the parasternal short-axis view at the aortic root With use of either the apical or the subcostal four chamber view, the diameter of the tricuspid anulus at /88/$35

2 72 LUNG T AL HOARDIOGRAPHI ASSSSMNT OF NONATS la Vol 12, No3 Figure 1 chocardiographic-angiographic correlate of a tripartite right ventricle in a patient with pulmonary atresia and intact ventricular septum A, Anteroposterior right ventriculogram showing an inlet (IN), trabecular portion (TRA) and infundibulum (INF) The infundibulum ends blindly (asterisk) and contrast medium regurgitates into the right atrium (RA) through the tricuspid valve (arrows) 8, Subcostal echocardiogram showing the three right ventricular components The trabecular (TRA) portion lies beyond the insertion of the papillary muscle (P) of the tricuspid valve end-diastole was measured (9) The diameter of the main pulmonary artery at end-systole and the right ventricular infundibulum at end-diastole was measured immediately distal and proximal to the atretic pulmonary valve, respectively, at the high precordial short-axis cut ardiac catheterization In all 27 neonates, cardiac catheterization and biplane (anteroposterior and lateral) left and right ventriculography were performed under general anesthesia By reviewing the cineangiocardiograms, the right ventricular morphology was determined according to the tripartite approach; associated right ventricular anomalies, tricuspid valve dysfunction and sinusoidal-coronary artery communications were identified The end-diastolic diameter of the tricuspid anulus and right ventricular infundibulum, respectively, were estimated from the biplane right ventriculograms using the known diameter of the catheter as the scale Similarly, the end-systolic diameter of the main pulmonary artery was measured from the lateral left ventriculogram when the artery was filled by contrast medium passing through the patent ductus arteriosus The angiocardiographic and echocardiographic findings and measurements were then compared Statistical analysis was performed with use of the unpaired Student's t test and linear regression when applicable Results In all 27 neonates, two-dimensional echocardiography disclosed normally connected cardiac chambers, an intact ventricular septum and a diaphragmlike pulmonary valve that failed to open during systole, indicating the diagnosis of pulmonary atresia and intact ventricular septum Subse- Figure 2 chocardiographic-angiographic correlate of a two-component right ventricle with absence of the trabecular portion A, Anteroposterior right ventriculogram showing an inlet (IN) and infundibulum (INF) but absence of the trabecular portion (double stars) 8 Subcostal echocardiogram with a two-component right ventricle Other abbreviations and symbols as in Figure I

3 JA Vol 12, No3 LUNG T AL 721 HOARDIOGRAPHI ASSSSMNT OF NONATS quent cardiac catheterization revealed the presence of pulmonary atresia and intact ventricular septum in 25 babies and "functional pulmonary atresia" (1) in the remaining 2, who had severe bstein's anomaly The latter condition was later confirmed at autopsy examination A description of other relevant observations among the 25 neonates with pulmonary atresia and intact ventricular septum follows Right ventricular morphology This was well defined by both echocardiography and angiocardiography Twelve babies had a tripartite right ventricle (Fig 1), 1 had a two-component right ventricle (9 had an absent trabecular portion [Fig 2] and 1 had an absent infundibular portion [Fig 3]) and 3 had a one-component right ventricle with an inlet only (Fig 4) Associated right ventricular anomalies Both echocardiography and angiocardiography independently diagnosed associated bstein's malformations of the tricuspid valve in two babies with a tripartite right ventricle chocardiographically, the displaced proximal attachment of the septalleafiet of the tricuspid valve into the right ventricular cavity was best seen in the apical four chamber view (Fig 5) Restricted Figure 3 chocardiographic-angiographic correlate of a twocomponent right ventricle with absence of the infundibulum (long segment atretic infundibulum) A, Anteroposterior right ventriculogram showing an inlet (IN) and trabecular portion (TRA) but absence of the infundibulum (white asterisks) B, chocardiogram (four chamber view) showing an apparently good sized right ventricle (RV), The short-axis view at the aortic root (AO) reveals discontinuity (black asterisks) between the main pulmonary artery (MPA) and the right ventricular (RV) cavity a = aorta; LA = left atrium; LV = left ventricle; RA = right atrium; S = ventricular septum Figure 4 chocardiographic-angiographic correlate of a diminutive right ventricle with an inlet only A, Anteroposterior right ventriculogram showing a diminutive right ventricle (RV) with an inlet only Note the small restrictive tricuspid valve (black arrows) B, chocardiogram (four chamber view) showing the very diminutive right ventricle (RV) with a small restrictive tricuspid valve (TV) (white arrows), chocardiogram (short-axis view at the aortic root [AOD showing absence of an infundibular cavity (black asterisks) of the very diminutive right ventricle (RV) Abbreviations as in Figure 3

4 722 LUNG T AL HOARDIOGRAPHI ASSSSMNT OF NONATS JA Vol 12, No3 Figure 5 chocardiographic-angiographic correlate of bstein's anomaly associated with pulmonary atresia and intact ventricular septum A, Lateral view of right ventriculogram showing the displaced tricuspid valve (black straight arrows) from the atrioventricular junction (curved black arrows) B, chocardiogram (four chamber view) showing displacement of the septal leaflet (white arrows) of the tricuspid valve (TV) from the central fibrous body () ARV = atrialized right ventricle; MV = mitral valve; other abbreviations as in Figure 3 movement of the tricuspid valve was identified by both imaging techniques in three babies who had a onecomponent right ventricle Angiocardiography disclosed a sinusoidal-coronary artery communication in five babies whose right ventricle lacked one or two components On the other hand, echocardiography demonstrated the coronary artery fistula in only one baby (Fig 6) and suggested its presence in two others The echocardiographic features that probably indicate the presence of these abnormal coronary artery communications include dilated proximal coronary arteries, unusual course of a coronary artery (Fig 7) and irregular spaces (sinusoids) within the "reflectile" myocardium oronary artery discontinuity from the aortic root was not observed Right ventricular inflow and outflow dimensions The echocardiographic and angiocardiographic dimensions of the tricuspid anulus, right ventricular infundibulum and main pulmonary artery and their correlations are depicted in Figures 8 through 1 Analysis by linear regression showed that the corresponding echocardiographic and angiographic dimensions correlated well (r > 8) The tricuspid annular diameters varied over a wide range Overall it was larger in babies with a tripartite (range 71 to 18 mm, mean 19) and two-component (range 68 to 18 mm, mean 9) right ventricle than in those with one-component right ventricle (range 57 to 67 mm, mean 63) Although there was no statistical difference in the tricuspid annular diameter between the tripartite and two-component right ventricles as well as the two- and one-component right ventricles, significant difference in tricuspid annular diameter existed between the tripartite and one-component right ventricles (p > ) The size of the right ventricular infundibulum also exhibited a wide range It was atretic in all three babies with a Figure 6 chocardiographic-angiographic correlate of a sinusoidal coronary arterial fistula A, Anteroporterior right ventriculogram showing a small right ventricle (RV) with a large fistula (black arrows) leading to the aortic root (AO) B, chocardiogram (short-axis view) at the aortic root (AO) showing the abnormal communication (white arrows) Abbreviations as in Figure 3

5 JA Vol 12, No3 LUNG T AL 723 HOARDIOGRAPHI ASSSSMNT OF NONATS mm 8 ~ 6 ::l Vl u :r: L 4 2 c r ~ O 89 : A 4 6 8mm nehoeardiographie measut'ement Figure 7 chocardiographic short-axis view at the aortic root (AO) The right coronary artery (arrows) runs an unusual course into the "rerectile" myocardium (m) The patient has a diminutive right ventricle (rv) with an inlet only (white arrows) ra = right atrium Figure 8 orrelation of the echocardiographic and angiographic measurements of the tricuspid annular diameter A, Measurements obtained from the anteroposterior view of the right ventriculogram versus those obtained from the four chamber view of the echocardiogram B, Measurements obtained from the lateral view of the right ventriculogram versus those obtained from the four chamber view of the echocardiogram ' ::l Vl u r: L 2 : ~ ' ::l Vl u :r: L 2 : A B em 2 em 2 o r ~ O 85 ehoeardiographie measurement r=o7s ehoea rdiog ra phie meas u reme nt 2em 2em mm 6 '- ::l Vl 4 u 3 r: L 2 c r = O 83 : B 4 6 7mm ehoeardioqraphie measurement Figure 9 orrelation of the echocardiographic and angiographic measurements of the size of the right ventricular infundibulum A, Measurements obtained from the anteroposterior view of the right ventriculogram versus those obtained from the high precordial short-axis view of the echocardiogram B, Measurements obtained from the lateral view of the right ventriculogram versus those obtained from the high precordial short-axis view of the echocardiogram one-component right ventricle and in one baby with a two-component right ventricle The mean infundibular diameter of the tripartite right ventricles (range 22 to 79 mm, mean 52) was significantly wider than that of the twocomponent right ventricles (range 21 to 65 mm, mean 38 p < 5) All but two babies had a main pulmonary artery diameter >4 mm (range 3 to 86 mm, mean 6) There was no demonstrable relation between the size of the main pulmonary artery and the right ventricular morphology Discussion Pulmonary atresia and intact ventricular septum has a high early and late mortality (2,3, II) It is generally accepted that the dismal outlook for patients with this anomaly may be related to associated right ventricular hypoplasia, tricuspid valve anomaly and the state of the ventricular myocardium (2,3,8) The presence of major sinusoidal-coronary artery communications may predispose to myocardial ischemia and

6 724 LUNG T AL HOARDIOGRAPHI ASSSSMNT OF NONATS JA Vol 12, No3 mm 9, c 8 Q) Q) ~ e 7 ~ ~ 6 > 5 Q)'- '" - 4 U '" oq) a ",'" - 3 "I~ o 2 ', r = O 85 c « mm chocardiographic measurement ( high precordial short axis cut) Figure 1 orrelation of the echocardiographic (high precordial short-axis view) and angiographic (lateral view) measurements of the size of the main pulmonary artery dysfunction (4,5,12) On the other hand, although overall the pulmonary artery diameter is reduced, major hypoplasia of the pulmonary arteries, so frequently seen in pulmonary atresia with ventricular septal defect, is rarely if ever found (1) To the best of our knowledge, pulmonary artery branch stenosis associated with pulmonary atresia and intact ventricular septum has never been reported chocardiographic assessment The present study shows that in neonates with pulmonary atresia and intact ventricular septum, two-dimensional echo cardiography allows accurate diagnosis and sizing of the right ventricular inflow and outflow orifices When combined with pulsed Doppler echocardiography, it permits differentiation of functional atresia from structural pulmonary atresia (13) One limitation of echocardiography is its low diagnostic yield in detecting sinusoidal-coronary artery communications However, these abnormal communications seldom occur in patients with a tripartite right ventricle and there are clues that indicate their existence The clues include a dilated proximal coronary artery, abnormally large intramyocardial coronary arteries and irregular spaces linical implications In the original study of the tripartite approach of right ventricular morphology in patients with pulmonary atresia and intact ventricular septum, Bull et al (8) found that patients with the largest tricuspid valve anulus were in the group in which all components of the ventricular cavity were present and those with the smallest anulus were in those groups with only an inlet portion to the ventricular cavity; the trend between groups was statistically significant Bull et al (8) proposed that the management of pulmonary atresia and intact ventricular septum could be based on the right ventricular morphology according to the tripartite approach However, in the present study, we, like others (14), failed to demonstrate a significant correlation between the diameter of the tricuspid annulus and the three different types of right ventricle, but we confirmed that in most cases a tricuspid valve with a diameter below the 99% confidence limits of the normal mean (15) was associated with a onecomponent right ventricle Thus, although the majority of tripartite right ventricles are suitable for pulmonary valvotomy/right ventricular outflow reconstruction (15,16), a small number can be diminutive with a tiny tricuspid anulus On the other hand, a two-component right ventricle may have a tricuspid anulus near normal size and an adequate infundibular cavity In view of this, we feel that right ventricular morphology and tricuspid annular and infundibular diameters should be assessed independently onclusions We suggest that detailed echocardiographic examination is the method of choice in the evaluation of pulmonary atresia and intact ventricular septum and that cardiac catheterization should be reserved for selected cases, eg, in cases with suspected major sinusoidalcoronary artery communications or in the rare situation in which the pulmonary artery anatomy is not well defined by echocardiography We acknowledge the technical assistance of sther Tamm, T References I Zuberbuhler JR, Anderson RH Morphological variations in pulmonary atresia with intact ventricular septum Br Heart J 1979;41: Freedom RM The morphologic variations of pulmonary atresia with intact ventricular septum: guidelines for surgical intervention Pediatr ardioi1983;4: De Leval M, Bull, Stark J, Anderson RH, Taylor JFN, Macartney FJ Pulmonary atresia and intact ventricular septum: surgical management based on a revised classification irculation 1982;66: Freedom RM, Harrington DP ontributions of intramyocardial sinusoids in pulmonary atresia and intact ventricular septum to a right -sided circular shunt Br Heart J 1974;36: Hubbard JF, Girod DA, aldwell RL, Hurwitz RA, Mahony LA, Waller BF Right ventricular infarction with cardiac rupture in an infant with pulmonary valve atresia with intact ventricular septum J Am oli ardiol 1983;2: Shinebourne A, Macartney FJ, Anderson RH Sequential chamber localization-the logical approach to diagnosis in congenital heart disease Br Heart J 1976;38: Goor DA, Lillehei Wo ongenital malformations of the heart New York: Grune and Stratton, 1975:11 8 Bull, De Leval MR, Mercanti, Macartney FJ, Anderson RH Pulmonary atresia and intact ventricular septum: a revised classification irculation 1982;66: Gutgesell HP, Bricker JT, olvin V, Latson LA, Hawkins P Atrioventricular valve annular diameter: two-dimensional echocardiographicautopsy correlation Am J ardiol 1984;53: Freedom RM, ulham G, Moes F, Olley PM, Rowe RD Differentiation of functional and structural pulmonary atresia: role of aortography Am J ardioi1978;41:914-2 II Miller GAH, Restifo M, Shinebourne A, et al Pulmonary atresia with intact ventricular septum and critical pulmonary stenosis presenting in the first month of life; investigation and surgical results Br Heart J 1973;35: Waldman JD, Lamberti JJ, Mathewson JW, George L Surgical closure of the tricuspid valve for pulmonary atresia, intact ventricular septum, and

7 JA Vol 12, No3 LUNG T AL 725 HOARDIOGRAPHI ASSSSMNT OF NONATS right ventricle to coronary artery communications Pediatr ardiol 1984;5: Smallhorn JF, Izukawa T, Benson L, Freedom RM Noninvasive recognition offunctiona1 pulmonary atresia by echocardiography Am J ardiol 1984 ;54: obanoglu A, Metzdrotf MT, Pinson W, Grunkemeier GL, Sunderland O, Starr A Valvotomy for pulmonary atresia with intact ventricular septum: a disciplined approach to achieve a functioning right ventricle J Thorac ardiovasc Surg 1985;89: De Leval M, Bull, Hopkins R, et al Decision making in the definitive repair of the heart with a small right ventricle irculation 1985 ;72(suppl 11): Joshi SV, Brawn WJ, Mee RBB Pulmonary atresia with intact ventricular septum J Thorac ardiovasc Surg 1986;91:192-9