CRP Beats Cholesterol for Predicting Stenosis

The results were reported at the annual Clinical Congress of the American College of Surgeons in New Orleans (LA, USA) in October 2004.

CRP is a common blood test for inflammation and carotid stenosis. In the study of 58 patients, researchers found that CRP was associated with carotid stenosis, while low-density lipoprotein (LDL), serum triglycerides, family history, and long-term glucose control were not associated with stenosis. The study is now being expanded to include more than 500 patients, who will be evaluated over the next three years to determine whether those with elevated CRP levels go on to have a transient ischemic attack (TIA) or a full-blown stroke.

"We will be following these patients every three to six months and tracking who has an adverse neurologic event related to cardiac disease,” explained Philip S. Mullenix, M.D., a resident in vascular surgery at Madigan Army Medical Center (Tacoma, WA, USA). "It will be interesting to see if patients with an elevated CRP have an increased risk down the road for an adverse neurologic outcome.”

Dr. Mullenix is aware that his research is raising more questions than it is answering. However, if CRP does predict neurologic disease due to atherosclerosis, monitoring CRP levels could lead to a whole new way of identifying patients who may need treatment to prevent brain attack. At the present time, patients with low LDL but elevated CRP are not currently placed on stating therapy. If elevated CRP is a danger sign for stroke, patients might be started on a statin even if their LDL is low, suggested Dr. Mullenix.

In addition, CRP may also be useful in helping to prioritize patients for carotid surgery. The standard way of determining whether a patient needs a carotid endarterectomy is based on the velocity of blood flow through the carotid arteries. However, velocity is a surrogate measure of buildup of plaque on the walls of blood vessels.

"What we're really interested in is plaque that has a propensity to cause a stroke,” added Dr. Mullenix. "It's thought that elevated CRP is associated with plaque that has ulcerated or thrombotic components and therefore is unstable.” Unstable or vulnerable plaque can break off and become lodged in blood vessels downstream, blocking blood supplies to the brain and causing a stroke.

"CRP might change the frequency of surveillance of patients with carotid disease,” explained Dr. Mullenix. "Patients with high CRPs might be assessed every six months instead of every year. In an adjunctive way, along with other risk factors, it might tip the balance toward surgery for those patients we're on the fence about in terms of our clinical impression.”

CRP is a general systemic marker for inflammation. It is increased in patients with rheumatoid arthritis, chronic inflammation, infection, and malignancy.




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