[Pathogenesis of acquired coronary anomalies. Case report]

The heart of a 44 years old man who died of a severe calcifying endocarditis of the aortic valves and the aortic root demonstrated a rare anomaly of the coronary arteries. The ostium and the stem of the left coronary artery were missing. In the left aortic sinus there was a small dimple covered by calcified tissue. Using histological serial sections a small vessel was detected that was completely obliterated by organized thrombotic tissue running between the small dimple in the aortic sinus and the main branches of the left coronary artery. This vessel was supposed to be the remaining stem of the left coronary artery. The regular branches of the left coronary artery were supplied by an anastomosis between the proximal part of the right coronary artery and the descending branch of the left coronary artery running within the upper interventricular septum. It has been suggested that this rare anomaly was caused by a gradual obliteration of the ostium and the stem of the left coronary artery during the course of the calcifying rheumatic endocarditis of the aortic valves.