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Vascular: Cerebral Atherosclerosis May Predict Post-CABG Stroke

Authors suggest evaluation of both intracranial and extracranial carotid arteries

Cerebral atherosclerosis is an important risk factor for stroke after coronary artery bypass grafting (CABG), according to a study published recently in the Journal of the American College of Cardiology. Pre-CABG evaluation of the cerebral arteries may therefore be a good practice.

Stroke is a common and serious post-CABG complication, and prior research suggested extracranial carotid artery disease to be a predictor. However, little data existed on atherosclerosis of the other cerebral arteries. The authors of the current study thus sought to learn more about atherosclerosis and the mechanisms underlying stroke after CABG. They tracked 1,367 CABG patients (mean age 63 years) who were members of the Asan Medical Center database in Seoul, South Korea. Each participant had pre-operative magnetic resonance angiography (MRA) including diffusion-weighted imaging, 3-dimensional time-of-flight MRA for intracranial arteries, and contrast-enhanced MRA for intracranial and extracranial arteries. Atherosclerosis was visually graded based on the number of cerebral arteries showing steno-occlusion, and the extent thereof. Cardiac surgeons who had completed at least 100 CABGs each performed the procedures. Whether to perform off-pump or conventional CABG was at each surgeon's discretion, with off-pump tending to be the choice in patients with severe atherosclerosis along the aortic arch.

Thirty-three patients had a stroke within 14 days of CABG; 15 of these strokes were defined as atherosclerotic. For each one-point increase in atherosclerosis score before CABG, the risk of stroke increased by about 1.3 times. “Cerebral atherosclerosis was closely related to the occurrence of post-CABG stroke, being both an independent risk factor for and the cause of a significant proportion of strokes,” the authors write. They conclude that evaluation of the intra- and extracranial cerebral arteries before CABG may be a useful way to predict stroke.

Source: Lee E-J, Choi K-H, Ryu J-S, et al. 2011. Stroke risk after coronary artery bypass graft surgery and extent of cerebral artery atherosclerosis. Journal of the American College of Cardiology 57:1811-1818.