Covert Strokes Common after Non-Cardiac Surgery

The main outcome was the association between covert stroke and cognitive decline. Patients, healthcare providers, and outcome adjudicators were masked to MRI results.

The results revealed that 78 patients (7%) experienced a perioperative covert stroke. Among the patients who completed one-year follow-up, cognitive decline occurred in 42% of those who had a perioperative covert stroke, and in 29% of participants who did not have one, for an overall incidence of perioperative covert stroke in one in 14 patients. Covert stroke was also associated with an increased risk of perioperative delirium, overt stroke, and transient ischemic attack (TIA) at one-year follow-up. The study was published on August 15, 2019, in The Lancet.

“Over the last century, surgery has greatly improved the health and the quality of life of patients around the world,” said lead author Marko Mrkobrada, MD, of the University of Western Ontario. “Surgeons are now able to operate on older and sicker patients thanks to improvements in surgical and anesthetic techniques. Despite the benefits of surgery, we also need to understand the risks.”

Although overt stroke occurs in less than one percent of adults following non-cardiac surgery and is associated with substantial morbidity, little is known about perioperative covert stroke. And while an overt stroke causes obvious symptoms, such as weakness in one arm or speech problems that last more than a day, a covert stroke is not obvious except on brain scans, such as MRI.

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University of Western Ontario