What are the risks of general anesthesia after a stroke?

A fellow caregiver asked...

My mother had a hemorrhagic stroke last year and has been doing well ever since. The problem is that she needs a hip replacement. The surgeon says it's too risky, but her quality of life would be so much better with a new hip. Is her risk of stroke or other complications under anesthesia significantly greater? And even if she can't have a hip replacement, what if she needs emergency surgery for something else?

Expert Answer

James Castle, M.D. is a neurologist at NorthShore University HealthSystem (affiliated with The University of Chicago) and an expert on strokes.

Usually general anesthesia poses little risk to patients who have suffered hemorrhagic strokes, which are most commonly caused by elevated blood pressure or abnormal blood vessels. Unless your mother's surgery requires that she not take blood pressure medicines beforehand, general anesthesia would be very unlikely to cause a dangerous rise in her blood pressure.

The same is not true, however, for patients with a history of an ischemic stroke (generally caused by a blood clot blocking an artery). There are three reasons for this. First, before most procedures the surgeon asks patients to stop their blood thinning medicines for fear of bleeding during the surgery. Therefore, there's a window of time during which the patient has a higher tendency to clot and have a stroke. Second, patients with ischemic strokes often have significant stenosis (narrowing) of their arteries, and these can become symptomatic when the blood pressure drops during general anesthesia. Third, if the operation involves manipulation of an artery, a cholesterol plaque could become unstable and cause a stroke, although this is not an issue during a hip replacement.