FREQUENCY AND PATHOGENESIS OF HEMODYNAMIC STROKE

Background and Purpose Hemodynamic stroke is a recognized but poorly d escribed entity. The aim of this study was to define the frequency and pathogenic mechanisms of hemodynamic stroke. Methods We prospectively studied 300 consecutive patients with acute ischemic stroke for evide nce of a hemodynamic mechanism. All patients with a probable or possib le thromboembolic source were excluded. Results Twenty-nine patients ( 9.6%) had documented or presumed hypotension at stroke onset, with 27 of 29 (93%) having watershed infarction on computed tomography (CT). M ost (21/29) patients had a slow (hours to days) progressive onset to s troke. Myocardial infarction, cardiac arrhythmias, and orthostatic cha nges in blood pressure related to diabetic dysautonomia and antihypert ensive therapy were the predominant causes of hypotension. Ten patient s had moderate or severe carotid stenosis (frequently bilateral); 9 ha d carotid occlusion (19/29 [66%]). Patients with normal carotid arteri es (10/29 [34%]) had hypotension with a stuttering onset to stroke and watershed infarction on CT. Many patients continued to have progressi ve neurological deterioration, often with ongoing hemodynamic instabil ity. Three of 7 patients who underwent carotid endarterectomy had furt her perioperative ischemic events. Five patients had myocardial infarc tion, and overall 4 died during 18.4 months of follow-up (mortality, 9 %/y). Conclusions Recognition of the clinical and CT features of hemod ynamic stroke allows early identification and management of cardiac an d carotid disease and correction of iatrogenic causes of hypotension, which may reduce the risk of further events.