Post-surgical stroke risk study identifies patient characteristics to watch for

George A. Mashour, M.D., Ph.D., assistant professor of anesthesiology and neurosurgery, and director of the Division of Neuroanesthesiology

Patients with kidney or blood pressure problems, or history of stroke, are more likely to have a stroke following surgery - even if the operation does not involve the heart or brain - according to a University of Michigan Health System study.

Strokes are known to occur after surgery, but the U-M study is one of the largest and most comprehensive to analyze how often the deadly complication happens and who is most likely to have a post-operative stroke.

"Our study was able to identify the numerous risk factors of postoperative stroke in patients undergoing non-cardiac surgery," says study lead author George A. Mashour, M.D., Ph.D., assistant professor of anesthesiology and neurosurgery, and director of the U-M Division of Neuroanesthesiology.

"Some of the factors included a previous heart attack, acute renal failure, past history of stroke, dialysis and hypertension. We also found that those who suffered a stroke following surgery were eight times more likely to die within 30 days of surgery," says Mashour.

The study was published in Anesthesiology, a publication of the American Society of Anesthesiologists.

Researchers analyzed records from more than 500,000 patients in the American College of Surgeons National Surgical Quality Improvement Program database to determine the incidence, predictors and outcomes associated with post-operative stroke.

More importantly, the authors developed a "risk index classification" to help guide clinicians as to who is at highest risk of postoperative stroke. Both the authors and editorial writers say physicians need to maintain vigilance for perioperative stroke. Neurologic function can be assessed at the bedside on routine examination, even by simply observing the patient's movements, speech, and cognition during a brief postoperative visit.

"Neurologic signs or symptoms should trigger stroke codes and stroke teams that can emergently triage patients for acute interventions such as thrombolysis and/or endovascular clot removal," an accompanying editorial's writer says. "Immediate treatment is paramount as outcomes worsen with time from ictus; 'time is brain.' "