Most Strokes Secondary to Coronary Artery Bypass Graft Surgery Are Embolic

Most strokes in association with coronary artery bypass graft (CABG) surgery have embolic etiologies, according to a report in the December issue of Stroke. The stroke etiology was most commonly embolic (62.1% of patients), followed by multiple etiologies (10.1%), hypoperfusion (8.8%), lacunar (3.1%), and thrombotic (1.0%).

Stroke follows CABG surgery in as many as 4.3% of patients, the authors explain, but little research has focused on identifying and understanding the etiology of such strokes. In the study, 54 strokes (12.9%) had unknown etiologies.

Dr. Donald S. Likosky from Dartmouth-Hitchcock Medical Center, Hanover, New Hampshire and colleagues in the Northern New England Cardiovascular Disease Study Group (NNECDSG) developed and implemented a classification system to identify the distribution and timing of stroke subtypes in 388 patients with the diagnosis of stroke after isolated CABG surgery.

Among the 372 patients for whom the timing of stroke occurrence was known, the report indicates, most occurred on the first postoperative day (41.7%), and an additional 20.4% occurred on the second postoperative day.

“Our findings suggest that the greatest opportunity for reduction in stroke rates may be realized through (1) identification of the association between processes of clinical care and sources of emboli and (2) redesign of clinical care to reduce and prevent their occurrence,” the researchers conclude.

“Part of our vision for improving care in our region has been individualizing the care that we deliver to a patient’s needs,” Dr. Likosky told Reuters Health. “The NNECDSG’s regional study of etiologic mechanisms has prompted us to begin identifying risk factors associated with development of different stroke mechanisms. This information will likely be valuable for the redesign of care to reduce a patient’s risk of developing a stroke secondary to CABG surgery.”

“Efforts to prevent sources of embolic material and the incidence of low cardiac output would likely reduce a patient’s risk of embolic and hypoperfusion strokes, respectively,” Dr. Likosky said.

Stroke 2003;34:2830-2834.