Coronary embolism and angina in mitral stenosis.

Coronary embolism has been considered a rare and often fatal mishap. The most frequently reported heart diseases causing coronary embolism have been syphilis and bacterial endocarditis (Shrader et al., 1956), so that coronary embolism might be expected to be decreasing in frequency. Our experience suggests, however, that its occurrence is by no means rare in rheumatic heart disease. The object of this paper is to report five patients with mitral stenosis who had coronary emboli and to comment on the significance of anginal pain and ischemic heart disease in mitral valve disease. None of the five patients had bacterial endocarditis. Evidence is presented to support our belief that coronary embolism is neither uncommon nor usually fatal, that it may be unobtrusive rather than dramatic, diagnosed retrospectively as often as currently, and that it is the most important cause of angina in patients with mitral stenosis. Since the first post-mortem description of coronary embolism was published by Virchow in 1856, 90 acceptable cases have been reported. Shrader et al. (1956) stated that coronary embolism was usually fatal, and quoted a mortality rate of 96 per cent in their review of 54 previously reported cases. Wenger and Bauer (1958) reviewed 61 such cases and described 15 more occurring at the Mount Sinai Hospital, New York, between 1929 and 1957 (an incidence at necropsy of 0-06 per cent). The commonest sources of embolism in 74 patients were fragments of vegetation in bacterial endocarditis in 47 (64%)0 aortic thrombus in 9 (12%) and intra-cardiac thrombus from the left ventricle after infarction or from the left atrium in mitral stenosis in 8 (11%). Three of these authors' cases of coronary embolism were found to be incidental to the cause of death at post-mortem examination, and all three were seen within a period of six months in 1957. In two of them, the source of the embolism was calcified left atrial mural thrombus, whereas in only one of the ten fatal cases seen during a 28-year period was left atrial thrombus due to mitral stenosis the source of the embolism. These authors suggest that coronary artery embolism with recovery may not be rare, and since their paper there have been reports of six other patients with coronary embolism incidental to the cause of death (Wigle, 1957; Kavanaugh et al., 1958; and Case records of the Massachusetts General Hospital, 1958). Study of the earlier reports suggests that instances in which recovery took place might not have been recognized.