Strokes after cardiac surgery: mostly right hemispheric ischemic with mild residual damage.

OBJECTIVE: Since cardiac surgery is now performed on patients with high risk for cerebrovascular disease, we studied the clinical findings and medium term outcome of patients with acute stroke/transient ischemic attack (TIA) after cardiac surgery. METHODS: All consecutive patients with acute stroke/TIA after cardiac surgery were prospectively observed during a 19 month period. Follow-up was between 3 months and 21 months. Risk factors, type of stroke, anatomic localization, initial neurological deficit and followup outcome were evaluated, using standard assessment scores. RESULTS: Among 406 patients operated (mean age 64.3 +/- 12.7 years, 284 males), 18 developed stroke and 2 TIAs (mean age 65.7 years, 13 males). There were no cases of intracerebral hemorrhage. Most of the strokes happened shortly after valve surgery (mean 1.3 days post operatively) and were right hemispheric (right = 11, left = 3; p = 0.034). Vertebrobasilar stroke appearance was delayed (mean: 8.25 days post operatively); they were attributed mostly to cardiac arrhythmias. Stroke/TIA patients did not have a higher preoperative risk than those without, but their cardiac functional score was worse (p = 0.01), and the average cardiopulmonary bypass time during surgery was longer (p = 0.009). Two patients died in hospital, both with vertebrobasilar stroke. Most of the hemispheric stroke patients became functionally independent (mean modified Rankin Scale < 2), even those with initial severe deficit. CONCLUSION: Strokes after cardiac surgery are mostly right hemispheric and exclusively ischemic. Outcome is relatively fair. We suggest an embolic injury to the right hemisphere, procedure related, as a possible mechanism.