Congenital pulmonary atresia with tricuspid insufficiency: morphologic study

Prominent venous valves in hypoplastic right hearts

To investigate the hypothesis that embryologic abnormalities in the venous valves may be associated with abnormal cardiac development, we examined the right atrial morphologic characteristics in 20 hearts with underdevelopment of the right heart and 17 normal hearts. In the study group, 16 (80%) of the patients had significantly enlarged eustachian valves, one (5%) was slightly enlarged, and three (15%) were smaller than expected. Five (25%) had cor triatriatum dexter. In comparison, eustachian valves in the control specimens were prominent in only one (6%), normal in five (29%), and almost absent in eight (47%). The thebesian valve was also more prominent in the study cohort when compared with controls (p < 0.05). No other morphologic features of the right atrium analyzed in this study differed from those found in normal specimens. We speculate that failure of the venous valves to regress appropriately may create abnormalities in fetal circulation that predispose the fetus to maldevelopment of the right heart structures.

Long-term results in neonates with pulmonary atresia and intact ventricular septum

Our entire institutional experience with pulmonary atresia and intact ventricular septum (1965 through 1987) included 115 patients, 16 of whom died before surgical intervention. Fifty-six percent of surgical patients (n = 99) had angiographic evidence of right ventricle-coronary arterial connections. The early mortality in the surgical group was 27.2%, and the actuarial survival was 24.7% +/- 6% at 13 years postoperatively. Multivariate analysis indicated that the presence of ventriculocoronary connections (p = 0.037), a decreasing ratio between right ventricular and left ventricular pressure at the initial cardiac catheterization (p = 0.007), and lower weight at operation (p = 0.001) were incremental risk factors for postoperative death; the presence of Ebstein's anomaly was an additional risk factor in the overall experience (including patients not surgically treated) (p = 0.01). Nearly all long-term survivors underwent at least one reoperation, including right ventricular outflow tract reconstruction (n = 39) and thromboexclusion of the right ventricle (n = 9). The presence of severe stenosis or interruption of the proximal left anterior descending coronary artery system was a uniformly lethal risk factor for patients undergoing these procedures (p = 0.0003). We conclude that surgical procedures that successfully decompress the right ventricle will usually result in biventricular circulation in and long-term survival of patients with pulmonary atresia with intact ventricular septum not complicated by Ebstein's anomaly or extensive ventriculocoronary connections. Decompression or thromboexclusion of the right ventricle is contraindicated in patients with ventriculocoronary connections and a right ventricle-dependent coronary circulation.

Pulmonary atresia with intact ventricular septum: a quantitative cineventriculographic study of the right and left ventricular function

Quantitative cineventriculographic measurements (ventricular volumes, ejection fraction, and myocardial mass) were obtained in 15 neonates with pulmonary atresia and intact ventricular septum. There was a wide dimensional range for the right ventricle, from a reduced through normal to enlarged. A restrictive tricuspid valve (less than 12 mm) was associated with a small or diminutive right ventricle. A normal function of the right ventricle was present only in those cases with normal-sized chambers. The left ventricular end-diastolic volume was always greater than normal. The ejection fraction was normal only if a normal myocardial mass was present. Additional abnormalities were frequent in the myocardium of both ventricles, such as extreme thinning of the wall of the right ventricle and hypoplasia or fibroelastosis of the left ventricle. All these factors can lead to a poor surgical prognosis despite good anatomical correction.

Functional aortic valve atresia in transposition of the great arteries

The criterion for the diagnosis of functional atresia of a patient semilunar valve is met when the pressure in a ventricle remains lower than that in the related great artery throughout systole so that no forward flow can occur. Functional pulmonary valve atresia has been well recognized in infants with normally related great arteries and massive tricuspid valve incompetence. The cardiac physiology and anatomy of an infant with transposed great arteries and functional aortic valve atresia is reported for the first time. The peak systolic pressure in the right ventricle was 30 mm Hg and in the aorta 64 mm Hg. The causes for right ventricular incompetence were abnormalities of the tricuspid valve and hypoplasia of the ventricular free wall. Three other cases with similar ventricular anatomy and physiology but with anatomic atresia of the aortic valve are reviewed. The possibility that under these physiologic circumstances during fetal life functional atresia develops first, and that anatomic fusion of idle semilunar cusps develops as a secondary phenomenon, is discussed.

Development of the ductus arteriosus in right ventricular outflow tract obstruction

We studied the morphology of the ductus arteriosus in 14 infants, ages 2--90 days. Eight (group 1) had pulmonary atresia (structural and functional) with an intact interventricular septum; six (group 2) had pulmonary atresia with a ventricular septal defect. The inferior angle of the ductus arteriosus at the aortic junction was measured in each patient. In group 1, this angle was obtuse in all but one patient. In group 2, the angle was acute in all. Further study of intracardiac anatomy suggested that in group 1, the obtuse inferior angle of the ductus arteriosus was the result of a late and progressive obstructive phenomenon that allowed normal right-to-left flow through the ductus arteriosus during much of fetal life. In group 2, the direction of ductus arteriosus flow (normally from the pulmonary trunk to the aorta) was reversed, and flowed from the aorta to the pulmonary trunk. This reversal of flow was probably of early onset in the fetus, the aorta receiving the total combined ventricular output, and produced a small ductus arteriosus with an acute inferior angle. It is extremely important not to rule out pulmonary atresia with an intact interventricular septum when aortography in the newborn shows a normal-sized ductus arteriosus with an obtuse inferior angle. Despite existing pulmonary atresia, these patients have neither a hypoplastic right ventricle nor discontinuity of the right ventricle with the pulmonary artery.

Right ventricular volume determinations in 18 patients with pulmonary atresia and intact ventricular septum. Analysis of factors influencing right ventricular growth

Right ventricular growth was assessed angiocardiographically in 18 patients with pulmonary atresia, intact ventricular septum, and hypoplastic and hypertensive right ventricle. A variety of surgical procedures were performed. In only 12 patients (66.7%) was right ventricular-pulmonary artery continuity achieved (group 1). Nine of these 12 patients persisted with systemic or suprasystemic right ventricular pressures. Among the six patients in whom right ventricular-pulmonary artery continuity was not achieved (group 2), all maintained suprasystemic right ventricular pressures. Right ventricular growth was assessed in groups 1 and 2. The patients were also subdivided according to the qualitative degree of tricuspid regurgitation as determined angiocardiographically on right ventricular cineangiocardiograms at the preoperative catheter study. Right ventricular growth to normal levels as evidenced by change in right ventricular end-diastolic volume was rarely observed in group 2 patients. Among the four patients with severe tricuspid regurgitation and a large tricuspid valve, right ventricular growth to normal levels was achieved whether they were in group 1 or group 2. Right ventricular growth is thus predicated on numerous morphologic factors in these patients. However, reconstitution of right ventricular-pulmonary artery continuity and a nonobstructive tricuspid valve are probably two of the more important factors.