Differentiation of functional and structural pulmonary atresia: Role of aortography

Among certain critically ill neonates with severe tricuspid regurgitation, including those with Ebstein's anomaly of the tricuspid valve, tricuspid valve dysplasia, transient tricuspid regurgitation of the newborn, Uhl's anomaly and hypoplasia of the right ventricle, selective right ventriculography may not distinguish between patients with associated functional and those with structural pulmonary atresia. In patients with a normal pulmonary valve and infundibulum, functional obstruction (nonvisualization of the pulmonary artery on right ventricular angiography when the pulmonary valve is anatomically patent and nonobstructive) results from a combination of massive tricuspid insufficiency and increased perinatal pulmonary vascular resistance. This differentiation between functional and structural pulmonary atresia is essential because of the therapeutic implications.In 33 neonates studied at cardiac catheterization from January 1974 through October 1977 standard hemodynamic measurements and right ventriculograms could not distinguish between functional and structural pulmonary atresia. Retrograde aortography, in the presence of a patent ductus arteriosus, provided excellent visualization of the pulmonary root and valve in these cases and, without exception, pulmonary regurgitation across the valve was observed in the patients with functional pulmonary atresia. Usually, the amount of regurgitated contrast material was dense and both the right ventricle and the right atrium were opacified. In addition, among the patients with functional pulmonary atresia, the pulmonary root and valve appeared wider and more patulous than in the patients with structural pulmonary atresia and normal or mildly increased right ventricular pressure was appreciated.     

Development of "subaortic stenosis" after pulmonary arterial banding for common ventricle

Progressive narrowing of the bulboventricular foramen is documented in four patients with single ventricle. The morphologic features in each case corresponded to single left ventricle with infundibular chamber. Two patients had a D-ventricular loop and the other two an L-loop. All four patients had transposition of the great arteries. Restriction of the bulboventricular foramen thus resulted in functional subaortic stenosis because the aorta originated above the infundibular chamber. The development of subaortic obstruction was documented by serial cardiac catheterization studies in two infants, one of whom underwent unsuccessful surgical enlargement of the bulboventricular foramen. In the other two patients the initial cardiac catheterization revealed no pressure gradient between the ventricle and aorta, but examination at necropsy revealed very severe obstruction at the bulboventricular foramen, thus suggesting that the obstruction had been acquired. In each patient, the progressive narrowing of the bulboventricular foramen occurred after pulmonary arterial banding and may have been causally related to this procedure. This functional subaortic obstruction developed in 4 of 31 patients (12.9 percent) with single left ventricle, transposition of the great arteries and pulmonary arterial banding. Clinical recognition of this development is predicated on (1) awareness that narrowing of the bulboventricular foramen in patients with single ventricle and pulmonary arterial banding may be common; (2) presence of symptoms such as angina; and (3) lack of continued clinical improvement in a patient whose pulmonary arterial band has significantly reduced pulmonary blood flow. Management of this subaortic stenosis requires surgical intervention. In the infant, a ventriculotomy in the outlet chamber will usually provide excellent exposure of the bulboventricular foramen, and surgical enlargement can be accomplished. In the older child with severe obstruction, marked muscle hypertrophy may obliterate the ventricular cavity, making ventricular partitioning difficult if not impossible.     

Preferential shunting of venous return from normally connected left pulmonary veins in secundum atrial septal defect

Preferential shunting of left pulmonary venous blood across a secundum atrial septal defect, a paradoxical hemodynamic finding, was documented in six patients by indicator-dilution techniques. Subsequent surgical findings excluded anomalous connection of the left pulmonary veins, which can result in similar or identical dye curve patterns. An adequate anatomic explanation for this physiologic paradox was apparent In only one patient.     

Ventricular septal defect and subaortic stenosis: An analysis of 41 patients

Forty-one patients with subaortic stenosis (SAS) and ventricular septal defect (VSD) were identified from the cardiac records of the Hospital for Sick Children, Toronto, Ontario. The diagnosis of an associated SAS was made clinically in only 1 patient, who had findings of left ventricular (LV) hypertrophy with strain on the electrocardiogram. There was a delay of 3.1 years between initial presentation and detection of SAS. The SAS was not diagnosed at initial catheterization in 17 patients and was confirmed at subsequent catheter studies in 8 patients, surgery in 5 and autopsy in 4. Associated defects included coarctation of the aorta in 12 patients, mitral valve abnormalities in 4, and right-sided obstructions, including anomalous right ventricular muscle bundles in 6 patients, tetralogy in 4 and pulmonic stenosis in 1 patient.

The mean gradient across the LV outflow tract was 25 mm Hg. Nineteen patients had serial catheters without intervening surgery, and the outflow gradient increased from a mean of 9 to 36 mm Hg. The mechanism of SAS consisted of fibrous diaphragm and fibromuscular obstruction in 31 cases, muscular narrowing in 4, protruding tricuspid valve leaflet in 2, hypertrophic cardiomyopathy in 2, anterolateral twist in 1 patient and redundant tissue tag in 1. Thirty-eight patients had a perimembranous VSD, 19 of whom had an associated so-called aneurysm of the membranous septum; 2 had an infundibular VSD and 1 patient had a central muscular defect. Although the SAS was located below the VSD in 30 cases, the associated heart failure and reduced cardiac output can mask the presence or severity of associated SAS. Cross-sectional echocardiography and axial angiography have greatly improved recognition of associated SAS.     

Truncal or aortic valve stenosis in functionally single arterial trunk: A clinical,hemodynamic and pathologic study of six cases

Stenosis of the semilunar valve in the presence of a functionally single arterial trunk is uncommon. Three patients with truncus arteriosus, two with tetralogy of Fallot and pulmonary atresia and one with pulmonary atresia and intact septum were diagnosed as having stenosis of the truncal or aortic valve on the basis of clinical, echocardiographic, hemodynamic and angiocardiographic findings. Echocardiograms consistently showed multiple diastolic closure lines and abnormal semilunar valves in addition to the aortic override in five patients and hypoplastic right ventricle in the patient with pulmonary atresia and intact septum. Peak systolic gradients between the left ventricle and truncus (or aorta) at cardiac catheterization ranged from 20 to 47 mm Hg. Retrograde aortography confirmed a domed and stenotic semilunar valve. Cyanosis was progressive in the three patients with pulmonary atresia. Two patients had arterial anastomosis, and one had a right ventricle-pulmonary arterial graft in addition to aortic valvotomy. One of the three patients with truncus arteriosus underwent complete repair in addition to truncal valvotomy but he died in the postoperative period. The other two patients with truncus arteriosus died of intractable congestive cardiac failure before surgical intervention.It is suggested that the presence of semilunar valve stenosis in these patients adversely affects the prognosis. The myocardium is already jeopardized as a result of hypoxia in pulmonary atresia and left ventricular diastolic overload in patients with truncus arteriosus. The added burden of semilunar valve stenosis may further compromise the functional status of the myocardium.     

Complete transposition of the great arteries and coarctation of the aorta

Thirty-two patients with complete transposition of the great arteries (TGA) and coarctation of the aorta (C of A) were seen at The Hospital for Sick Children, Toronto, Canada, between 1963 and 1983. Three patients had only mild C of A and have not required coarctectomy (Group I); 29 had a severe form of C of A (Group II). Two patients in Group I and 21 in Group II had a ventricular septal defect. Subaortic obstruction was present in 5 patients in Group II. The mechanisms included anterior deviation of the infundibular ventricular septum, anomalous right ventricular muscle bundles, and abnormal ventriculoinfundibular fold. Five patients in Group II had a hypoplastic right ventricle. Coarctectomy was performed in 25 patients, and 5 died (20% mortality rate). Sixteen patients had repair for TGA (13 Mustard, 2 Jatene, 1 Rastelli), and 2 died (12% mortality rate). Life-table analysis shows that only 68% of the patients with TGA and C of A survived the first month of life. The 5-year survival in this group was 57%. In the same period, 94% of patients with uncomplicated TGA survived the first month of life and the 5-year survival rate was 89%.     

The criss-cross and superoinferior ventricular heart: an angiocardiographic study

The angiocardiographic features of 11 patients with superoinferior and criss-cross type of atrioventricular (A-V) connections are presented. These unusual ventricular relations are thought to result from postseptation disturbances of ventricular looping. The angiocardiographic appearance of criss-cross is really an illusion, and the A-V connections among these patients are either concordant, discordant or straddling. The often small right A-V valve inflow and sinus portion of the ventricle, combind with the ventricular rotational anomaly, combine to give the angiocardiographic perception of criss-cross. A review of the 11 patients from this institution and those previously reported on suggests that most patients have a transposition of malposition of the great arteries; many have a small right ventricle, and about half have pulmonary outflow tract obstruction. In addition to the obvious embryologic, morphologic and clinical implications of these distorted ventricular loops, the criss-cross A-V hearts raise questions about the various segmental nomenclatures applied to these types of congenital heart disease.     

Mechanism of acquired right ventricular outflow tract obstruction in patients with ventricular septal defect: an angiocardiographic study

Right ventricular outflow tract obstruction can complicate the natural history of patients with isolated ventricular septal defect. Although numerous pathologic mechanisms may be responsible for this phenomenon, it is less clear what the frequency is of each of these mechanisms in any cohort of patients studied in a single institution. We identified 20 patients with isolated ventricular septal defect from 1970 to 1981 who acquired a right ventricular outflow tract gradient of 25 mm Hg or more. They ranged in age at the initial catheterization investigation from 4 days to 23 months and at the subsequent study from 13 months to 8 years. Angiographically, 2 mechanisms were implicated in the 20 patients. Hypertrophy of right ventricular anomalous muscle bundles was identified in 19 of the 20 while hypertrophy of a malaligned infundibular septum (that is, classic tetralogy type) was identified in only 1 patient. These data indicate that acquired right ventricular outflow tract obstruction is rarely of the classic tetralogy type.     

Bilateral ductus arteriosus (or remnant): an analysis of 27 patients

Bilateral ductus arteriosus (DA) was clinically recognized in 27 patients studied angiographically from 1963 through May 1983. Distal bilateral DA origin of non-confluent pulmonary arteries was identified in 15 patients, ectopic or distal ductal origin of 1 pulmonary artery in 9 patients (5 without evidence of intracardiac disease) and isolation of the left subclavian artery in 3 (all 3 of whom had a right aortic arch). Other conditions reported to be associated with bilateral DA include interruption of the aortic arch with isolation of a subclavian artery, aortic atresia with interruption of the aortic arch in which bilateral DA supports the entire systemic circulation, bilateral DA complicating forms of congenitally malformed hearts other than those just stated, and, rarely, bilateral DA in isolation. Understanding the symmetric or paired nature of the primitive aortic arch system in the developing human heart facilitates recognition of the patterns of fourth and sixth arch anomalies seen with bilateral DA.     

Coarctation of the aorta or subaortic stenosis with atrioventricular septal defect

Thirty patients are reported with atrioventricular (AV) septal defect and either coarctation of the aorta (C of A) or subaortic stenosis (SAS) or both. All patients had normal left ventricles as assessed by angiography (21 of 30 patients) or necropsy (9 of 30). Three groups were recognized. Groups I and II included 19 patients with AV septal defect (12 complete, 7 partial) and C of A with or without SAS, 11 patients with AV septal defect (5 complete, 6 partial) and SAS. In Group I, preductal C of A was diagnosed in 16 of 19 patients. Concomitant angiographic evidence of SAS was present in 2 cases, the mechanism being exaggerated anterior displacement of the left AV valve. In Group III, at the time of diagnosis left ventricular-aortic peak systolic pressure gradients of greater than 20 mm Hg were present in 9 patients, 2 of whom had gradients greater than 50 mm Hg. Angiographic diagnoses were: discrete fibrous diaphragm in 4, fibromuscular obstruction in 5, dynamic tunnel in 1, and chordae from left AV valve to LV outflow tract in 1. Thus, SAS in AV septal defect is most often due to a discrete anatomic lesion. Hemodynamic data show that SAS can be progressive, both before and after the surgical management of the AV septal defect.     

Congenital unilateral pulmonary vein stenosis complicating transposition of the great arteries

Four patients with transposition of the great arteries and unilateral pulmonary vein (PV) stenosis, all left-sided, were studied. Two patients had an intact ventricular septum (1 with a patent ductus arteriosus), 1 patient had a ventricular septal defect and 1 had a ventricular septal defect with pulmonary stenosis. Clinical signs, such as recurrent pneumonia, unilateral pulmonary edema and pleural effusion, were present preoperatively in 2 patients. Diagnosis was made at cardiac catheterization by cineangiography in 2 patients and at Mustard operation when the PV orifices were inspected in the other 2. PV dilatation was attempted in 3 patients, 1 before correction (age 6 months), 1 during and after it (ages 1 and 3 years, respectively) and 1 during corrective surgery (age 15 months). In the fourth patient only the intracardiac baffle was enlarged near the left PV orifices. In the first patient, at Mustard operation (age 18 months), only a fibrotic PV without an orifice was found; this patient died after surgery. The mean follow-up in the 3 survivors was 3.2 years (range 2 months to 7.6 years). All have severe residual PV obstruction documented by technetium-99m lung perfusion scans that show decreased flow to the left lung (0 to 16% total counts; normal 45 %); 2 have unilateral pulmonary edema and 1 has pulmonary artery pressure at systemic level. It is believed that in patients with transposition of the great arteries, left-sided unilateral PV stenosis is a congenital anomaly that becomes progressive as a result of postnatal preferential flow to the right lung.     

Letter: Maximal treadmill testing.

Patients with isolated total interruption of the arch of the aorta not accompanied by other cardiovascular anomalies may survive to advanced age. Their symptoms and course resemble those of patients with postductal coarctation of the aorta. However, there are basic differences in the pathologic findings in these two types of anomalies that may be of aid in the radiographic diagnosis.     

Compression of intrapulmonary bronchi by abnormally branching pulmonary arteries associated with absent pulmonary valves

In 3 patients with absent pulmonary valve syndrome and absent ductus arteriosus, the lungs were injected and analyzed postmortem using morphometric techniques. Two patients had tetralogy of Fallot and 1 had D-transposition of the great arteries, the latter being the first autopsy-proved case of absent pulmonary valve with transposition. In addition to the expected dilatation of the central pulmonary arteries and compression of the mainstem bronchi, postmortem pulmonary arteriography revealed a bizarre pattern of hilar branching. Instead of single segmental arteries, tufts of arteries arose which entwined and compressed the intrapulmonary bronchi. In all 3 patients the histologic structure of the pulmonary arteries was abnormal. The elastic lamina of the media of the right and left pulmonary arteries were increased in number outside the lung, but were decreased within the lung. At both sites, the elastic laminae were thickened and fragmented. In the 2 ventilator-dependent patients, there was slight medial hypertrophy and extension of muscle into normally nonmuscular arteries. In 1 of the 2 cases in which the number of bronchial generations was counted, they were decreased, and in the 1 case in which bronchial count was unknown, alveolar multiplication was severely impaired. Therefore, our data may explain why, in some patients with absent pulmonary valve syndrome, relief of compression of the mainstem bronchi alone does not appreciably alleviate or reverse severe respiratory disease.     

Echocardiographic evaluation of right ventricular function in complete transposition of the great arteries: angiographic correlates.

Right ventricular function of patients with complete transposition of the great arteries may be impaired. To assess whether the M mode echocardiogram could predict right ventricular function 64 echocardiograms and ventricular angiograms of 62 patients were studied, 33 obtained before repair of the defect (group I) and 31 (including 2 from patients in group I) obtained after the Mustard procedure (group II). Each group was subdivided according to whether a ventricular septal defect or patent ductus arterposus was or had been present preoperatively.The right ventricular preejection period was expressed as the ratio of the observed to the predicted value for a systemic left ventricle. This value was above normal In all groups and was not significantly different in the 13 patients with right bundle branch block. The observed ejection time expressed as a percent of that predicted for a systemic left ventricle correlated with right ventricular ejection fraction (r = 0.47). The ratio of the observed preejection period/ejection time had a higher correlation with right ventricular ejection fraction (r = ? 0.70). Nine patients had a low right ventricular ejection fraction (an ejection fraction of 0.55 or less was considered indicative of poor right ventricular function). These nine patients were all in group II and all had right bundle branch block.Most patients with poor right ventricular function had had a ventricular septal defect or patent ductus arteriosus before repair of the transposition, and postoperatively had angiographic tricuspld regurgitation, right bundle branch block, a preejection period/ejection time ratio greater than 0.55 and a percent predicted ejection time of 96 percent or less. Most patients who had good right ventricular function (ejection fraction greater than 0.55) had none of these findings. Systolic time intervals obtained with M mode echocardiography can be used for the assessment and longitudinal follow-up of right ventricular function in patients with transposition.     

Thallium-201 myocardial imaging in anomalous left coronary artery arising from the pulmonary artery: Applications before and after medical and surgical treatment

Thallium-201 myocardial imaging was performed on six patients with an anomalous left coronary artery arising from the pulmonary artery. Initial images in three children (aged 4 months, 12 months and $\text{2}\text{1}\text{2}\text{years}$, respectively) demonstrated anterolateral perfusion defects in agreement with the electrocardiographic localization of infarction. Repeat imaging in two patients 2 to 3 months later, after clinical improvement with anticongestive therapy, demonstrated a reduction in the perfusion defect. In 3 other patients (aged 16, 16 and 20 years, respectively) thallium-201 scans performed during exercise stress demonstrated normal myocardial perfusion 7 to 15 years after operation (ligation of anomalous left coronary in two, ligation plus bypass graft in one).Thallium-201 imaging appears to be helpful in monitoring changes in myocardial perfusion before and after medical or surgical treatment of an anomalous left coronary artery, and may shed light on the pathophysiology of the defect. A possible practical limitation of thallium-201 imaging in this condition is the difficulty of imaging subendocardial infarction.