Intraoperative Hypotension and Perioperative Ischemic Stroke after General Surgery A Nested Case-control Study

Background: Postoperative stroke is a rare but major complication after surgery. The most often proposed mechanism is an embolus originating from the heart or great vessels. The role of intraoperative hypotension in the occurrence and evolution of postoperative stroke is largely unknown. Methods: A case-control study was conducted among 48,241 patients who underwent noncardiac and nonneurosurgical procedures in the period from January 2002 to June 2009. A total of 42 stroke cases (0.09%) were matched on age and type of surgery to 252 control patients. Conditional logistic regression analysis was used to estimate the effect of the duration of intraoperative hypotension (defined according to a range of blood pressure thresholds) on the occurrence of an ischemic stroke within 10 days after surgery, adjusted for potential confounding factors. Results: After correction for potential confounders and multiple testing, the duration that the mean blood pressure was decreased more than 30% from baseline remained statistically significantly associated with the occurrence of a postoperative stroke. Conclusions: Intraoperative hypotension might play a role in the development of postoperative ischemic stroke. Especially for mean blood pressure values decreasing more than 30% from baseline blood pressure, an association with postoperative ischemic stroke risks was observed.