431 The Role of Stroke Prophylaxis in Traumatic Vertebral Artery Injury: A Literature-Based Cohort Study

INTRODUCTION: Vertebral artery injury (VAI) can precipitate posterior circulation strokes acutely following blunt trauma. VAI severity is conventionally classified by the Denver grading system, but at present, there remain no guidelines that translate Denver injury grade to antiplatelet or anticoagulant recommendations. METHODS: Four databases (Ovid MEDLINE, Ovid Embase, Cochrane Central, and Scopus) were queried to identify all studies evaluating stroke risk following blunt VAI. Stroke rates following VAI were compared for patients managed with observation only or antiplatelets. Sub-analyses stratifying outcomes by injury severity (Denver grade) were performed. Effectiveness of antiplatelet use was summarized by the number needed to prevent (NNP) post-VAI stroke. RESULTS: Of 2,256 unique studies identified, 34 comprising 1,138 patients were incluced. Overall VAI-related stroke risk was 1.75% before admission and 3.40% after admission. Grades I and II had a cumulative stroke risk of 2.43% (95% CI: 0.98-4.94), which differed significantly (p < 0.01) from Grade IV-associated risk (10.10%; 95% CI: 4.95-17.79). Overall stroke risk in patients without prophylactic treatment was 10.00% (95% CI: 9.07-10.9), and 0.43% (95% CI: 0.01-1.06) in their counterparts who received antiplatelets (NNP = 10). Patients with grade I-II VAI receiving no treatment had 5.19% (95% CI: 1.43-12.77) stroke risk compared to 0.55% (95% CI: 0.01-3.02) treated with antiplatelet agents (NNP = 22). Among grade IV VAI, the stroke risk among patients that received no treatment was 21.21% (95% CI: 8.98-38.91), while none of the patients that received antiplatelet therapy developed stroke (NNP = 5). CONCLUSIONS: The majority of VAI-related stroke occurs after initial presentation, suggesting a potential for prevention of post-VAI stroke. Antiplatelet treatment was associated with significantly lower odds of post-VAI stroke among patients with Grade I, II, or IV injury, with the impact increasing within injury grade. The results suggest the positive impact of antiplatelet therapy with increasing VAI injury severity.