Double Dose Plavix No Benefit After Stenting

Reviewed by  Zalman S. Agus, MD ; Emeritus Professor

Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner Earn CME/CE credit

A double dose of clopidogrel (Plavix) following percutaneous coronary intervention does not appear to reduce cardiovascular events among stent patients with high platelet reactivity on a standard dose of clopidogrel, according to results of the GRAVITAS trial.

The randomized trial of more than 2,000 PCI patients, found that at six months, the rate of cardiovascular death, MI, or stent thrombosis was 2.3% whether patients received a standard or double dose of clopidogrel ( P =0.97), Matthew Price, MD, of Scripps Clinic in La Jolla, Calif., and colleagues reported.

The trial results, originally reported at the American Heart Association meeting in November 2010, "do not support a uniform treatment strategy of high-dose clopidogrel in patients with high on-treatment reactivity identified by a single platelet function test after PCI," Price and co-authors wrote in the March 16 issue of the Journal of the American Medical Association .

"Alternative treatment strategies incorporating platelet function testing merit further investigation," the group added.

Agreeing in an accompanying editorial were Paul Gurbel, MD, and Udaya Tantry, PhD, of Sinai Hospital of Baltimore, who wrote that "it is hoped that future studies evaluating different platelet function cut-points and more potent P2Y12 inhibitors will be effective."

GRAVITAS was a double-blind, randomized, active-control trial conducted at 83 centers across North America. It included 2,214 patients who underwent PCI with drug-eluting stents and who had high on-treatment platelet reactivity 12 to 24 hours after the procedure, according to the VerifyNow P2Y12 assay.

Initially, the study included patients with stable coronary artery disease or non-ST-elevation acute coronary syndromes, although once the trial it was under way, the protocol was changed to allow patients with ST-elevation MI to join.

High platelet reactivity was defined as a PRU (P2Y12 reactivity unit) of 230 or higher.

The researchers randomized the patients to a high dose of clopidogrel -- a first-day dose of 600 mg followed by 150 mg daily thereafter -- or a standard dose -- no loading dose followed by 75 mg daily.

All patients also received aspirin 75 to 162 mg daily.

Within 30 days of randomization, average PRU declined in both groups, although the drop was greater in the high-dose group. That resulted in a significant 22% absolute reduction in the rate of high on-treatment reactivity (40% versus 62%, P

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