Strokes after cardiac surgery and relationship to carotid stenosis

Abstract

Objective: To critically examine the role of significant carotid stenosis in the pathogenesis of postoperative stroke following cardiac operations.

Design: Retrospective cohort study.

Setting: Single tertiary care hospital.

Participants: A total of 4335 patients undergoing coronary artery bypass grafting, aortic valve replacement, or both.

Main outcome measures: Incidence, subtype, and arterial distribution of stroke.

Results: Clinically definite stroke was detected in 1.8% of patients undergoing cardiac operations during the same admission. Only 5.3% of these strokes were of the large-vessel type, and most strokes (76.3%) occurred without significant carotid stenosis. In 60.0% of cases, strokes identified via computed tomographic head scans were not confined to a single carotid artery territory. According to clinical data, in 94.7% of patients, stroke occurred without direct correlation to significant carotid stenosis. Undergoing combined carotid and cardiac operations increases the risk of postoperative stroke compared with patients with a similar degree of carotid stenosis but who underwent cardiac surgery alone (15.1% vs 0%; P = .004).

Conclusions: There is no direct causal relationship between significant carotid stenosis and postoperative stroke in patients undergoing cardiac operations. Combining carotid and cardiac procedures is neither necessary nor effective in reducing postoperative stroke in patients with asymptomatic carotid stenosis.