Introduction: Cervical artery dissection is a common cause of stroke in young people. The temporal profile of stroke risk after cervical artery dissection remains uncertain.
Methods: We performed a crossover-cohort study using administrative claims data on all emergency department visits and acute care hospitalizations from 2005-2011 in California, 2006-2013 in New York, and 2005-2013 in Florida. Using previously validated ICD-9-CM codes, we identified patients with a cervical artery dissection and no prior or concurrent stroke diagnosis. Previously validated diagnosis codes were used to identify the primary outcome of ischemic stroke. We compared the risk of stroke in successive 2-week periods during the 12 weeks after dissection versus the corresponding 2-week period 1 year later. Absolute risks increases were calculated using a Mantel-Haenszel estimator for matched data. In a sensitivity analysis, we limited our population to only patients that presented with typical symptoms of cervical artery dissection in order to ensure we identified patients with acute dissection.
Results: We identified 2,791 patients with dissection. The absolute increase in stroke risk was 1.25% (95% CI, 0.84-1.67%) in the first 2 weeks after dissection compared to the same time period 1 year later. The absolute risk increase was 0.18% (95% CI 0.02-0.34%) during weeks 3-4, and was no longer significant during the remainder of the 12 week post-dissection period. Our findings were similar in a sensitivity analysis identifying patients who presented with typical symptoms of acute dissection.
Conclusions: The increased risk of stroke following cervical artery dissection appears to be limited to the first 2 weeks.