Clinical and radiological outcomes of acute ischemic stroke patients without angiographic occlusion on digital subtraction angiogram. A pooled analysis of case series.

Introduction: Approximately 20-30% of the patients with acute ischemic stroke do not have any occlusion demonstrated on initial digital subtraction angiography (DSA). We sought to determine the risk and rates of cerebral infarction and favorable neurological outcome in this group of acute ischemic stroke patients.

Materials And Methods: Patients were identified from a prospectively maintained stroke database and from literature search of MEDLINE, PubMed, and Cochrane databases. All patients had initial neurological assessment on National Institutes of Health Stroke Scale (NIHSS). Patients then underwent DSA after initial head computed tomography (CT) scans. Follow-up radiological assessment at 24-72 h was performed with CT and magnetic resonance imaging scans. Association of stroke risk factors with clinical and radiological outcomes was estimated.

Results: A total of 81 patients was analyzed (mean age 63 years; 28 were women). The median NIHSS score was 8 (range 2-25). None of the patients received either intravenous or intra-arterial thrombolytic. Cerebral infarction was detected in 62 (76%) of the 81 patients. Twenty-four to 48-h NIHSS was available for 51 patients only. Neurological improvement was observed in 22 (43%) of the 51 patients. Favorable outcome ascertained at 3-month follow-up was seen in 48 (59%) of the 81 patients. After adjusting for age, sex, and baseline NIHSS, male patients [odds ratio (OR) 4.5 (1.4-14.3), p value = 0.01] and patients with age >or=65 [OR 4.3 (1.2-16.2), p value = 0.03] have a higher risk of cerebral infarcts on the follow-up imaging. Similarly, patients who presented with <10 NIHSS had a better 3-month outcome than those with >10 NIHSS [OR 0.21 (0.08-0.61), p value = 0.004].

Conclusion: Ischemic stroke patients without arterial occlusion on DSA have a higher risk of cerebral infarction and disability particularly in men, patients over 65 years of age and with NIHSS >or=10. The cause of infarction may have been arterial obstruction with spontaneous recanalization or small vessel occlusion not visible on DSA.