Structural abnormalities of great arterial walls in congenital heart disease - Light and electron microscopic analyses

Background-Great arteries in congenital heart disease (CHD) may dilate, bec ome aneurysmal, or rupture. Little is known about medial abnormalities in t hese arterial walls. Accordingly, we studied 18 types of CHD in patients fr om neonates to older adults. Methods and Results-Intraoperative biopsies from ascending aorta, paracoarc tation aorta, truncus arteriosus, and pulmonary trunk in 86 patients were s upplemented by 16 necropsy specimens. The 102 patients were 3 weeks to 81 y ears old (average, 32 +/- 6 years). Biopsies were examined by light (LM) an d electron (EM) microscopy; necropsy specimens by LM. Positive aortic contr ols were from 15 Marfan patients. Negative aortic controls were from 11 cor onary artery disease patients and 1 transplant donor. Nine biopsies from ac quired trileaflet aortic stenosis were compared with biopsies from bicuspid aortic stenosis. Negative pulmonary trunk controls were from 7 coronary ar tery disease patients. A grading system consisted of negative controls and grades 1, 2, and 3 (positive controls) based on LM and EM examination of me dial constituents, Conclusions-Medial abnormalities in ascending aorta, paracoarctation aorta, truncus arteriosus, and pulmonary trunk were prevalent in patients with a variety of forms of CHD encompassing a wide age range. Aortic abnormalities may predispose to dilatation, aneurysm, and rupture. Pulmonary trunk abnor malities may predispose to dilatation and aneurysm; hypertensive aneurysms may rupture. Pivotal questions are whether these abnormalities are inherent or acquired, whether CHD plays a causal or facilitating role, and whether genetic determinants are operative.