Richard Van Praagh

Causes of Death After the Modified Norwood Procedure: A Study of 122 Postmortem Cases

BACKGROUND Although the results of the modified Norwood procedure as palliation for the hypoplastic left heart syndrome have improved considerably, in-hospital mortality remains high (28% to 46%). METHODS To establish the causes of death and consider their therapeutic applications, we reviewed our pathology experience from 1980 to 1995, inclusive, regarding 122 patients who died after undergoing the Norwood procedure. RESULTS The most important causes of death were found to be impairment of coronary perfusion (33 patients, 27%), excessive pulmonary blood flow (23 patients, 19%), obstruction of pulmonary arterial blood flow (21 patients, 17%), neoaortic obstruction (17 patients, 14%), right ventricular failure (16 patients, 13%), bleeding (9 patients, 7%), infection (6 patients, 5%), tricuspid or common atrioventricular valve dysfunction (6 patients, 5%), sudden death from presumed arrhythmias (6 patients, 5%), and necrotizing enterocolitis (3 patients, 3%). In 26 patients (21%), more than one factor appeared responsible for death. CONCLUSIONS The leading causes of death after the Norwood procedure were found to be largely correctable surgical technical problems associated with perfusion of the lungs (36%), of the myocardium (27%), and of the systemic organs (14%).

Interrupted aortic arch: Surgical treatment☆

Abstract A new palliative surgical procedure for interruption of the aortic arch was successfully performed in an infant. A Teflon graft was inserted from the main pulmonary artery to the descending thoracic aorta in order to bypass a stenotic ductus arteriosus, and both pulmonary artery branches were banded to reduce the pulmonary blood flow. This procedure may also prove life-saving in the hypoplastic left heart syndrome, with the addition of atrial septal defect creation when left atrial decompression is indicated. This syndrome was the commonest cause of death from congenital heart disease in the first month of life in our recent experience (31 percent), based on a consecutive autopsy series of 174 neonates with congenital heart disease. The anatomic findings in 10 autopsy cases of interrupted aortic arch are summarized. A new understanding of the morphogenesis of these anomalies is presented, based on correlation of embryologic and pathologic data. The literature on interruptions of the aortic arch is reviewed, and surgical experience with these malformations is considered in detail.

Cor triatriatum: Pathologic anatomy and a consideration of morphogenesis based on 13 postmortem cases and a study of normal development of the pulmonary vein and atrial septum in 83 human embryos☆

Abstract The principal pathologic findings in 13 cases of classical cor triatriatum were presented, including the first documented case of complete transposition of the great arteries and the fourth reported case of tetralogy of Fallot with cor triatriatum. Findings relevant to this anomaly were reported from a study of normal development of the pulmonary vein and atrial septum, based on 83 human embryos. Attention was focused on the origin, course, and incorporation of the common pulmonary vein and on the origins and development of septum primum, the left venous valve, and the intersepto-valvular space. The pathologic and embryologic findings strongly suggest that cor triatriatum results from entrapment of the left atrial ostium of the common pulmonary vein by tissue of the right horn of the sinus venosus from which septum primum develops, leading to failure of incorporation of the common pulmonary vein into the left atrium during the fifth embryonic week.

Tetralogy of Fallot : Underdevelopment of the Pulmonary Infundibulum and Its Sequelae

Abstract It is proposed that the tetralogy of Fallot basically is a “monology”, just 1 anomaly, namely, underdevelopment of the subpulmonary infundibulum and its sequelae. The parietal band (crista supraventricularis) and the adjacent infundibular free wall together form an abnormally small cone (conus) of muscle beneath the pulmonary artery, whereas the septal band is normally formed. The hypothesis that the essence of tetralogy is an abnormally small subpulmonary conus is illustrated by angiocardiographic and anatomic findings in typical tetralogy compared with the normal. This unifying concept, which needs experimental embryologic assessment, facilitates angiocardiographic diagnosis of “masked” tetralogy in which the presence of this anomaly may be obscured by associated malformations. To demonstrate this, a rare case is presented, the fourth known patient with coexisting tetralogy and cor triatriatum. This 20 year old man also had a patent ductus arteriosus and a right pulmonary sequestration. The resulting systemic level of pulmonary hypertension “masked” the coexistence of tetralogy, which angiocardiography made evident. Despite the absence of a pulmonary outflow tract gradient due to the association of severe pulmonary hypertension, autopsy confirmed that this patient displayed the angiocardiographic hallmark of tetralogy: an abnormally small subpulmonary infundibulum.

Clinical,angiocardiographic, and pathologic findings in 100 patients

Salient clinical, hemodynamic, angiocardiographic, and pathologic findings are presented in 100 patients with truncus arteriosus communis, 79 of whom were studied at autopsy. In this study of typical truncus, all had a ventricular septal defect (type A). Truncus with a partially formed aorticopulmonary septum (type A1) was much the commonest form (50%). Cases with no remnant of aorticopulmonary septum (type A2) were second in frequency (21%). The distinction between types A1 and A2 could not be made with certainty in 9%, because these types merge into one another. Cases with absence of either pulmonary artery branch (type A3) were the least frequent form (8%). Truncus with interruption, atresia, preductal coarctation, or severe hypoplasia of the aortic arch (type A4) constituted 12%. The diagnosis of truncus is primarily angiocardiographic. The plane of the truncal valve in the lateral projection is distinctive. It tilts anteriorly, facing the patients toes, which can be of assistance in differential diagnosis. The angiocardiographic features of type A4, although unfamiliar, are pathognomonic. Since the median age at death was only 5 weeks, and in view of the difficulties associated with pulmonary artery banding, our goal should be the surgical correction of truncus during the first and second months of life.

Anatomic types of congenital mitral stenosis: Report of 49 autopsy cases with consideration of diagnosis and surgical implications☆

Abstract In a series of 49 autopsy cases of congenital mitral stenosis, four anatomic types were found: (1) typical congenital mitral stenosis with short chordae tendineae, obliteration of interchordal spaces and reduction of interpapillary distance (24 cases, 49 percent); (2) hypoplastic congenital mitral stenosis almost always associated with a hypoplastic left heart syndrome (20 cases, 41 percent); (3) supramitral ring (6 cases, 12 percent); and (4) parachute mitral valve (4 cases, 8 percent). The median ages at death were as follows: parachute mitral valve, 9 11 12 years ; supramitral ring, 5 6 12 years ; typical congenital mitral stenosis, 6 months, and hypoplastic congenital mitral stenosis, 5 days. Thus, parachute mitral valve had the best natural history and the hypoplastic type of mitral stenosis the worst; that of the other two types was intermediate. Associated malformations were present in 96 percent of cases, endocardial sclerosis or florid endocardial fibroelastosis occurring in 47 percent, hypoplasia of the aortic isthmus in 37 percent, aortic valve stenosis in 29 percent, aortic atresia in 29 percent and coarctation of the aorta in 27 percent of the cases. On the basis of an understanding of the pathologic anatomy, real time twodimensional echocardiography probably will make it possible to make the differential diagnosis among the four major anatomic types of congenital mitral stenosis. Mitral valvuloplasty of several new types appears to merit trial as the initial surgical procedure. At present, mitral valve replacement should be deferred as long as possible.

Transposition of the great arteries with posterior aorta, anterior pulmonary artery, subpulmonary conus and fibrous continuity between aortic and atrioventricular valves.

Abstract A newly recognized type of complete d-transposition of the great arteries is presented. The aortic valve was posterior and inferior to the pulmonary valve in 4 postmortem cases. Deficiency of the subaortic muscular conus permitted tenuous aortic-tricuspid fibrous continuity in 3 of 4 cases and tenuous aortic-mitral fibrous continuity in all by means of a high ventricular septal defect. The crista supraventricularis (parietal band) was entirely above the morphologically left ventricle and was much shorter than normal (average length 3 mm, normal average length 7 mm). The morphogenesis of these transpositions cannot be explained by the straight truncal septum hypothesis because the truncal septum in these cases was spiral, not straight. These new findings can readily be explained by the conal growth hypothesis, and they indicate the desirability of a literal (accurate) definition of transposition of the great arteries: aorta arising above the morphologically right ventricle and pulmonary artery originating above the morphologically left ventricle. Malpositions of the great arteries include transposition, double-outlet right ventricle, double-outlet left ventricle and anatomically corrected malposition (“transposition”). Transposition of the great arteries is a relation, not an entity. It is 3 different entities in terms of conal malformations (on the basis of these 4 cases plus a control study of 100 unselected autopsy cases of transposition, accurately defined): (1) subaortic conus with pulmonary-mitral fibrous continuity, 92 percent; (2) subaortic and subpulmonary (bilateral) conus without semilunar-atrioventricular fibrous continuity, 8 per cent; and (3) markedly foreshortened subpulmonary conus with tenuous aortic-atrioventricular fibrous continuity, as in these 4 cases, much less than 1 percent.

Anatomic types of ventricular septal defect with aortic insufficiency: Diagnostic and surgical considerations

Abstract A series of 11 postmortem cases of ventricular septal defect (VSD) with aortic insufficiency (AI) was presented, and an anatomic classification of VSD with AI was proposed. There are two principal anatomic types: VSD beneath the crista supraventricularis (Type I), and VSD beneath the pulmonary valve (Type II). With a subcristal VSD (Type I), there are two subtypes: without pulmonary infundibular stenosis (Type Ia), and with pulmonary infundibular stenosis (Type Ib). Subcristal VSD with AI (Type I) occurred in seven cases. In six of these, the development of AI appeared basically to be related to the underdevelopment of one aortic commissure, usually the right coronary-noncoronary (4:6 cases). A functionally bicuspid aortic valve resulted in five cases. No pulmonary infundibular stenosis (Type Ia) was found in three cases, while four displayed mild to moderate pulmonary infundibular stenosis (Type Ib). The clinical and laboratory picture without pulmonary stenosis was that of AI with a maladie de Roger type of VSD, while the picture with stenosis was that of AI with acyanotic (atypical) tetralogy of Fallot. Subpulmonary VSD with AI (Type II) occurred in four cases. The subpulmonary VSD is a conal septal defect, the conal septal portion of the crista supraventricularis being absent or defective. All four cases had normal aortic commissures. AI resulted from herniation of the right coronary aortic leaflet through the large subpulmonary VSD into the right ventricular outflow tract, resulting in a mild to moderate pulmonary outflow tract gradient in all. Subcristal VSD with AI, with or without pulmonary stenosis, usually was an aortic commissural deficiency problem (in 6:7 cases). Subpulmonary VSD with AI always was a hernia of a basically normal aortic valve into the right ventricular outflow tract (in 4:4 cases). Since the surgical management of the two principal types of VSD with AI is different, their differential diagnosis is of practical clinical importance.

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.

Cardiac malformations in trisomy-18: A study of 41 postmortem cases

The cardiac malformations in 41 karyotyped and autopsy cases of trisomy-18 are presented in detail. The salient findings were a ventricular septal defect in all cases; tricuspid valve anomalies in 33 cases (80%); pulmonary valve anomalies in 30 (70%); aortic valve malformations in 28 (68%); mitral valve anomalies in 27 (66%); polyvalvular disease (that is, malformations of more than one valve) in 38 (93%); a subpulmonary infundibulum (conus) in 40 (98%); a bilateral conus with a short subaortic infundibulum in 1 case with double outlet right ventricle (this being the only documented case of bilateral infundibulum in trisomy-18); double outlet right ventricle in 4 cases (10%), three having a subpulmonary infundibulum only and all 4 having mitral atresia; tetralogy of Fallot in 6 cases (15%), 2 having pulmonary atresia; and a striking absence of transposition of the great arteries and inversion at any level (visceral or cardiac), findings that appear to be characteristic of all trisomies. These data suggest that excessive chromosomal material (as in trisomies) may result in situs solitus at all levels. The malformations of the atrioventricular and semilunar valves were characterized by redundant or thick myxomatous leaflets, long chordae tendineae and hypoplastic or absent papillary muscles. The ventricular septal defect was associated with anterosuperior conal septal malalignment in 25 cases (61%). On the basis of the characteristic valvular lesions, the type of ventricular septal defect and the absence of transposition or inversions, two-dimensional echocardiographic diagnosis of trisomy-18 in the fetus may become possible.