NONATHEROSCLEROTIC CAUSES OF CORONARY ARTERY OBSTRUCTION



Although uncommon, there are several nonatherosclerotic causes of coronary artery obstruction. Emboli to coronary arteries can occur in infective endocarditis, from mural thrombi in the left atrium or ventricle, from prosthetic valves, from cardiac myxomas, or associated with cardiopul­monary bypass or coronary arteriography. Trauma to coronary arteries can be associated with both penetrating and nonpenetrating injuries. Various forms of arteritis (syphilis, polyarteritis nodosa, Takayasu’s disease, disseminated lupus erythe­matosus, and rheumatoid arthritis) can affect the coronary arteries. The mucocutaneous lymph node syndrome (Kawasaki’s disease) presents as a febrile illness in a child usually below the age of 10. Multiple organ systems can develop vas­culitis, but the most significant feature is a vas­culitis involving intima, media, and adventitia of the coronary arteries that results in aneurysm and sometimes thrombus formation. Mortality is 1 to 2 per cent secondary to complications from cor­onary arterial involvement.

Dissection of the aorta involving the coronary arteries or dissection of the coronary arteries themselves may occur in patients with connective tissue abnormalities of the aorta (for example, Marfan’s syndrome). In situ thrombosis may occur in certain rare disorders (for example, polycy­themia vera, thrombocytosis, or disseminated in­travascular coagulation). Spasm of the coronary artery (Prinzmetal’s angina, discussed below) is another nonatherosclerotic cause of coronary ob­struction.