C-Reactive Protein Appears To Predict Vein-Graft Disease In Peripheral Bypass Patients

By Mitchell L. Zoler

PHILADELPHIA -- A high serum level of C-reactive protein was linked to an increased rate of cardiovascular events, including vein-graft disease, in a study of 91 patients who underwent lower-extremity bypass surgery.

Although this preliminary study involved a small number of patients, it was the first to examine the relationship between serum levels of C-reactive protein (CRP) and the progression of vein-graft disease, Dr. Christopher D. Owens said at the Vascular Annual Meeting. A much larger body of evidence has linked elevated serum levels of CRP with an increased risk of other cardiovascular disease events, including coronary and cerebrovascular events.

High serum CRP "may identify a subgroup of patients undergoing lower-extremity bypass who need more aggressive antiplatelet and lipid-lowering therapy, and who need more intensive vein-graft monitoring," said Dr. Owens, a vascular surgeon at Brigham and Women's Hospital in Boston.

The study enrolled patients who were scheduled to undergo lower-extremity bypass surgery for critical limb ischemia at either of two hospitals in Boston between February 2004 and December 2005. All patients underwent autologous vein grafting. The study excluded patients who were older than 90 and those with a systemic infection. Prior to surgery, serum specimens were collected from all patients and CRP levels were measured using a high-sensitivity assay. The patients' median CRP level at baseline was 3.2 mg/L, substantially higher than the 1.5 mg/L median level for unselected adults in the United States.

The primary end point was a composite of graft-related events, including stenosis, occlusion, need for revision surgery, or amputation of the index limb. Also included were contralateral limb events, such as amputation or disease progression requiring revascularization, all deaths, myocardial infarctions, and strokes.

After an average follow-up of almost a year, 39 patients had at least one primary-end point event. Average CRP level at baseline in these patients was 6.02 mg/L, compared with an average of 2.74 mg/L in the 52 patients without events. Graft-related events accounted for over half the total number of events. Among patients with a CRP level of more than 5 mg/L at baseline, the incidence of events after was 60%. In contrast, among patients with a CRP level of 5 mg/L or less at baseline, the incidence of events was 32%.

In a multivariate analysis that adjusted for baseline differences among the patients, CRP level was the only variable that significantly correlated with the incidence of graft-related or other cardiovascular events, Dr. Owens said.

Brigham and Women's Hospital holds patents that relate to the use of inflammatory markers such as CRP in the management of cardiovascular diseases.