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Asymptomatic carotid artery stenosis does not increase stroke risk after CABG

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – Asymptomatic carotid artery stenosis does not increase the risk of stroke or mortality after coronary artery bypass graft (CABG) surgery, according to a report in the August 4th online Stroke.

The prevalence of significant carotid artery stenosis in patients undergoing CABG may range as high as 20%, but there remains no clear consensus as to the optimal management of these patients.

“In order to prevent stroke during CABG, a good study of the carotids should be performed,” Dr. Ron Waksman from Washington Hospital Center, Washington, DC told Reuters Health by email. “The degree of the carotid disease and the disease of the aortic arch and ascending aorta should be taken into considerations to recommend first on carotid intervention prior to CABG.”

Dr. Waksman and colleagues investigated the impact of severe asymptomatic carotid artery stenosis on in-hospital rates of stroke and all-cause mortality and on the 30-day rate of all-cause mortality in 878 patients undergoing isolated CABG who had preoperative carotid duplex ultrasound.

Among these patients, 68.3% had bilateral stenosis less than 50%, 18.4% had 50% to 74% stenosis (12.2% unilateral and 6.2% bilateral), and 13.3% had at least 75% stenosis (10% unilateral and 3.3% bilateral).

Compared with patients having severe carotid artery stenosis (at least 75%), patients with nonsevere carotid artery stenosis showed no significant difference in the rates of stroke (3.4% versus 3.6%; P=1.0), all-cause mortality (3.4% versus 4.2%, P=1.0), or any of the other examined clinical parameters.

Similarly, there was no significant difference in the 30-day rate of all-cause mortality between patients with severe carotid artery stenosis (3.4%) and patients with nonsevere carotid artery stenosis (2.9%)(P=0.51).

“Although relatively small in sample size, our results add to the growing body of evidence arguing against routine synchronous carotid intervention in patients undergoing CABG who are also found to have asymptomatic, severe carotid artery stenosis,” the researchers conclude. “However, there is no doubt that such an approach is indicated in a selected cohort of patients, such as those with the most severe disease in association with unstable cardiac symptoms and/or significant comorbidities.”

“Currently there is no justification to intervene on the asymptomatic patient with carotid disease,” Dr. Waksman said. “We need to know if intervention should be preformed routinely for patients subjected to CABG. Further, we need to look for other correlates to stroke during CABG, as carotid disease in asymptomatic patients does not seem to correlate well with stroke during CABG.”

“We don’t understand well the causality of stroke during surgery and research should be targeted to these patients who had stroke to explore other causalities for stroke associated with CABG,” Dr. Waksman concluded. “The decision to perform carotid imaging and intervention in association with CABG should be individualized and further studied.”

Patients With Severe Asymptomatic Carotid Artery Stenosis Do Not Have a Higher Risk of Stroke and Mortality After Coronary Artery Bypass Surgery
Stroke 4 August 2011.