Although certain surgeries, such as cardiac, neurologic, and vascular procedures, and risk factors such as cigarette smoking, male gender, and history of transient ischemic attacks have been established as associated with increased incidence of perioperative stroke, no one has evaluated surgery and anesthesia alone as a possible independent risk factor for development of stroke.

Using a medical record linkage system to the Rochester Epidemiology Project, Wong et al.  retrieved records of 1,455 people who had an incident (first-time) of ischemic stroke from 1960 to 1984. An equal number of age-and gender-matched controls were identified from the same database. With the additional usage of the Mayo Surgical Information Retrieval System, the team then identified all stroke cases in which surgery with either general anesthesia or central neuroaxis blockade had been performed within 1 yr before the stroke date.

A conditional logistic regression model was used to estimate the odds of stroke after surgery and general anesthesia. The team identified 59 patients and 17 controls who underwent surgery within 30 days before their stroke or index date. After adjusting for previously identified risk factors (male gender, cigarette smoking, history of transient ischemic attacks, among others) the team found that undergoing surgery 30 days before the index date was an independent risk factor for stroke. The risk of perioperative ischemic stroke was increased even after general, non–high-risk surgeries. The mechanisms underlying this increased risk, of course, require further investigation.