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Cardiac malformations in trisomy-18: a study of 41 postmortem cases
S Van Praagh1, T Truman, A Firpo
1Department of Cardiology, Children's Hospital, Boston, Massachusetts 02115.
Insights
Trisomy-18 frequently causes severe cardiac defects, including ventricular septal defects and polyvalvular disease. These specific malformations may enable prenatal diagnosis via echocardiography.
Area of Science:
- Cardiology
- Genetics
- Developmental Biology
Background:
- Trisomy 18 (Edwards syndrome) is a genetic disorder associated with significant congenital anomalies.
- Cardiac malformations are common in trisomy 18 but detailed characterization is crucial for diagnosis and understanding pathogenesis.
Purpose of the Study:
- To comprehensively analyze the spectrum of cardiac malformations in a cohort of trisomy 18 cases.
- To identify specific cardiac features that could aid in the prenatal diagnosis of trisomy 18.
Main Methods:
- Detailed autopsy and karyotypic analysis of 41 cases with trisomy 18.
- Systematic documentation of all cardiac structural abnormalities, including septal defects, valve anomalies, and outflow tract abnormalities.
Main Results:
- All cases exhibited ventricular septal defects. High prevalence of tricuspid (80%), pulmonary (70%), aortic (68%), and mitral (66%) valve anomalies were observed.
- Polyvalvular disease (93%) and subpulmonary infundibulum (98%) were nearly universal. Transposition of great arteries and visceral inversions were notably absent.
- Ventricular septal defects were often associated with anterosuperior conal septal malalignment (61%).
Conclusions:
- Trisomy 18 is characterized by a consistent pattern of cardiac malformations, including specific valvular and septal defects.
- The absence of transposition and inversions, alongside characteristic valvular lesions, suggests potential for two-dimensional echocardiographic diagnosis of fetal trisomy 18.
Abstract:
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.