The surgical anatomy of the left ventricular outflow tract in hearts with ventricular septal defect and aortic arch obstruction.

BACKGROUND: Profound understanding of the left ventricular outflow tract (LVOT) anatomy is crucial to improve surgical results in patients with aortic arch obstruction, ventricular septal defect, and subaortic stenosis.

METHODS: We studied the morphology of the LVOT in 32 postmortem hearts with aortic arch obstruction and a ventricular septal defect. In case of subaortic obstruction, the length of the subaortic muscular component was measured anteriorly and posteriorly within the left ventricle.

RESULTS: Seven of the 32 hearts had no subaortic stenosis. Nine had aortic override, which caused LVOT narrowing. Sixteen hearts contained a subaortic shelf, downstream to the ventricular septal defect, which deviated into the left ventricle in 15. In 10 of these the shelf was muscular; in 6 it was a fibrous ridge. In cases with a muscular shelf, the posterior part was significantly shorter than the anterior part (p < 0.004). In 9 hearts the LVOT was further narrowed because of the abnormal relationship between the mitral valve and the subaortic shelf.

CONCLUSIONS: The present study confirms the complexity of LVOT stenosis in aortic arch obstruction and ventricular septal defect and provides a better understanding of the options to achieve surgical relief.