Changing trends in the etiologic diagnosis of ischemic stroke.

The evaluation of victims of ischemic stroke has evolved over the last few years, primarily as a result of the introduction of innovative, sensitive, and informative diagnostic procedures. The role of the neurologist appears to have been redefined as one in which the identification of the presumptive cause and mechanism of the stroke is one of the primary responsibilities. We compared the etiologic stroke subtypes of patients entered into the Saint Louis University Stroke Registry for the period January to June, 1986 (Group A), with analogous data collected in patients entered from January to June, 1992 (Group B). Group A included 57 patients whose stroke subtype distribution was as follows: 19% due to athero-thromboembolism, 18% cardiogenic, 5% lacunar, and 4% due to other causes. In addition, 54% of patients had strokes of unknown etiology. Group B comprised 137 patients with the following etiologic distribution: 35% cardiogenic, 26% atherothrombolic, 3% lacunar, and 6% from other causes. Only 29% had strokes of unknown etiology. The apparent increase in the proportion of cardiogenic strokes may be related to wider utilization of transesophageal echocardiography. There was also a significant drop in the proportion of strokes of unknown etiology. Finally, in comparison with other stroke registries, our data suggest that many small strokes may also result from cardiogenic embolism. These apparent changes in the proportion of stroke subtypes should be considered when patients are being evaluated for risk stratification.