Increased risk associated with combining carotid artery, coronary artery surgeries

Among patients undergoing evaluation for coronary artery bypass surgery, stroke neurologists are frequently consulted when the patient also has severe carotid artery stenosis (blockage of an artery that supplies blood to the brain).

In a small number of these cases, a carotid endarterectomy is performed at the same time as the bypass surgery, with the assumption that combining the procedures in a single surgical event may decrease subsequent risk of stroke or death. While combining these procedures has become more routine, a recent Canadian study, published in the April 26 issue of Neurology, suggests there is little evidence to demonstrate that this practice reduces the risk of stroke or death. Neurology is the scientific journal of the American Academy of Neurology.

Coronary artery bypass graft (CABG) surgery is a common major operation. CABG involves creating a detour or “bypass” around the blocked part of a coronary artery to restore the blood supply to the heart muscle. Carotid endarterectomy (CEA) is another relatively common operation that removes plaque from the walls of one or both arteries in the neck that supply oxygenated blood to the brain. There are several factors that may influence the outcomes of combining these surgical procedures, the most likely of which is the severity of vascular disease among these patients. Other factors include unstable angina, myocardial infarction or arrhythmia, previous stroke, and the skill and experience of the surgeon.

Although there has been an increase in the combined CEA-CABG procedure, the actual benefits to patients are not yet clear. “We sought to explore the use of these combined procedures in Canada, to evaluate its utilization over time, and to assess outcomes,” said study author Michael D. Hill, MD, MSc, of the University of Calgary in Alberta.

Between 1992 and 2001, all patients who underwent CABG at a Canadian hospital (excluding Quebec) were studied. Of the 131,762 patients who underwent CABG, 669 (0.51 percent) underwent combined CEA-CABG. The in-hospital death rate was 4.9 percent, and the post-operative stroke rate was 8.5 percent among patients who had the combined procedure, compared to 3.3 percent and 1.8 percent among patients who had CABG alone. After adjustment, the risk of death was not statistically different between the two groups, but an excess risk of stroke remained in the combined CEA-CABG group of 6.8 percent compared to 1.8 percent in the CABG group.

“Because the stroke risk of the combined surgical procedures remained significantly higher than in the CABG procedure alone, we believe further, randomized trials are necessary to demonstrate the appropriateness of combining these procedures,” concluded Hill.

In an accompanying Neurology editorial, Patrick Pullicino, MD, of the University of Medicine and Dentistry of New Jersey, affirms the need for continuing study. Pullicino noted outcomes of the recent Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE), that have shown carotid angioplasty and stenting, pre-operative alternatives to CABG surgery, can be performed with a low combined stroke and death rate in high-risk patients with carotid stenosis.

“As a result of the SAPPHIRE study, pre-CABG carotid angioplasty with or without stenting has replaced CEA-CABG at several centers in the U.S., leaving the burden on surgeons who perform CEA-CABG to show that it can be performed with acceptable risks,” noted Pullicino.

The Canadian Institutes for Health Research provided funding for the study.