CORONARY-ARTERY ABNORMALITIES AND RIGHT VENTRICULAR HISTOLOGY IN HYPOPLASTIC LEFT HEART SYNDROME

Objectives. To determine whether right ventricular preservation is compromised in any anatomic subgroup of hypoplastic left heart syndrome, we assessed the coronary artery anatomy and myocardial histologic features of 151 postmortem specimens with hypoplastic left heart syndrome. Background. Although previous studies have shown that coronary artery abnormalities are more prominent in the subgroup of patients who have a patent mitral valve and obstructed aortic valve, it has not been established that these abnormalities compromise right ventricular perfusion. Methods. Eighty-nine specimens with a patent mitral valve and aortic atresia, 52 with mitral and aortic atresia and 10 with patent mitral and aortic valves were examined. Histologic sections of the right ventricle, left ventricle and coronary arteries were obtained from 64 study hearts and 5 control hearts. Results. Gross coronary anomalies included coronary-cameral communications (n = 29), single left coronary artery (n = 2), single right coronary artery (n = 1) and tortuosity (n = 19). Coronary-cameral communications and tortuosity were significantly associated with the subgroup that had mitral hypoplasia and aortic atresia. Coronary artery wall thickness relative to lumen diameter was not different among the subgroups. No areas of coronary artery stenosis or interruption were discovered. Although endocardial fibroelastosis of the left ventricle was strongly associated with the mitral hypoplasia and aortic atresia group, the right ventricular histologic findings were similar in all subgroups and were not differentially affected by older age. Conclusions. Although the incidence of coronary abnormalities is greater in patients with mitral hypoplasia and aortic atresia, in this study there was no apparent difference in perfusion of the right ventricle among the anatomic subgroups of hearts with hypoplastic left heart syndrome.