An atypical cause of aortic valve prolapse.

We encountered a surgical case of aortic valve prolapse caused by a fissure formed in the commissural region and coronary cusp, and we achieved a favorable outcome. On pathologic examination, the fissured valve was found to be myxoid degeneration with ruptured elastic fibers and clustering of foamy macrophages, and it was diagnosed as an atherosclerotic change not associated with rheumatic change. The fissure appeared to develop because of hypertensive stress in a region rendered vulnerable by atherosclerosis. Although this mechanism is atypical, it should be recognized that poorly controlled hypertension can cause aortic valve prolapse and induce acute heart failure.