What raises risk of stroke after surgery?

University of Michigan study shows kidney and blood pressure problems can lead to post-operative stroke

Ann Arbor, Mich.  Patients with kidney or blood pressure problems, or past history of stroke, are more likely to have a stroke following surgery, even if the surgery does not involve the heart or brain.

Strokes are known to occur after surgery, but a University of Michigan Health System study published in the June issue of Anesthesiology is one of the largest and most comprehensive to analyze the incidence, outcomes and the specific risk factors associated with post-operative stroke.

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

“Some of the factors included myocardial infarction, acute renal failure, past history of stroke, dialysis and hypertension. We also found that stroke was associated with an eight-fold increase in postoperative mortality within 30 days," Mashour says.  

Researchers analyzed patient records of more than 500,000 patients in the American College of Surgeons National Surgical Quality Improvement Program database to determine the frequency of stroke, as well as which patients are most at-risk.

More importantly, the authors developed a “risk index classification” to help guide clinicians as to who is at highest risk of postoperative stroke.

Additional U-M authors: Amy M. Shanks, M.S., and Sachin Kheterpal, M.D., MBA.

Reference: “Perioperative stroke and associated mortality after noncardiac, nonneurologic surgery,” Anesthesiology, Vol. 116, No. 6, May 25, 2011.




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