Clinical Study of Potential Embolic Sources in Patients with Ischemic Cerebrovascular Diseases

ABSTRACT

BACKGROUND: The etiologies of ischemic cerebrovascular diseases are various-thrombosis or artery to artery embolism, cardiogenic embolism and lipohyalinosis. In the past embolic cerebral infarct was thought to occur uncommonly. But these days substantial portion of patients have been found to have potential embolic sources by transesophageal echo cardiography and carotid duplex doppler. As transesophageal echocardiography has a high yield for identification of potential sources of cardiac embolism in patients with ischemic cerbrovascular diseases, its use has been increasing. In Korea an increasing number of patients with ischemic cerebrovascular diseases have been examined by transesophageal echocardiography since 1990. But in all the previous studies transesophageal echocardiographic evaluation has been confined to the patients with high probability of embolic cerebral infarct. All kinds of ischemic cerebrovascular diseases patients have never been examined by transesophageal echocardiography and carotid duplex doppler and the prevalence of potential embolic sources in Korean ischemic cerebrovascular disease patients is not known. The aim of this study was to evaluate the prevalence of potential cardiovascular embolic sources by transesophageal echocardiography and carotid duplex doppler in unselected patients with ischemic cerebrovascular diseases. METHODS: We evaluated all kinds of ischemic cerebrovascular diseases patients admitted from 1994. 9. 1. until 1995 9. 31. to the Departments of Neurology and Internal Medicine of Kangnam General Hospital. We evaluated them by transesophageal echocardiography, carotid doppler, brain CT(or brain MRI). A significant carotid stenosis was defined as a duplex scandetected lesion producing at least 50% vessel narrowing. The following echocardiographic findings were defined prospectively as potential cardiac sources of embolism : atrial appendage or left atrial cavity thrombus, spontaneous echocardiographic contrast, atrial septal aneurysm, interatrial shunt, ventricular aneurysm, ventricular thrombus, myxomatous mitral valve and protruding atherosclerotic plaque in the ascending aorta or transverse aortic arch. RESULTS: Of 64 patients admitted during the study period, 30 were excluded(Three patients were critically ill, and twenty seven patients refused diagnostic work-up.). Thorough diagnostic work-up was performed in 34 patients. Transesophageal echocardiographic positive findings were present in six patients(17.6%). Of them four(4/34, 11.7%) had spontaneous echo contrast, two(2/34, 5.8%) had left atrial thrombi, one(1/34, 2.9%) had ascending aorta atheroma. Eleven patients(11/34, 32.3%) had abnormalities in carotid doppler study. Five patients(5/34, 14.7%) had abnormalities both in transesophageal echocardiography and carotid doppler study. CONCLUSIONS: The results suggest that among ischemic cerebrovascular diseases patients substantial portion of patients have potential embolic sources. The prevalence of potential embolic sources in Korea may be higher than previously expected. Because the relative small number of the patients studied make it difficult to generalize the results, further studies with a large number of patients are needed.