Low-Dose Aspirin After PCI Safer, as Effective as High Dose


NEW ORLEANS — Low-dose aspirin appears to be as effective as–but considerably safer than–the higher doses favored by most American cardiologists for prevention of recurrent cardiac events after percutaneous coronary intervention, Dr. Sanjit S. Jolly said at the annual meeting of the American College of Cardiology.

He presented a retrospective observational analysis of the Clopidogrel in Unstable Angina to Prevent Recurrent Ischemic Events in Patients Undergoing Percutaneous Coronary Intervention (PCI-CURE) trial database, which concluded that the adjusted risk of major bleeding within 8 months after the procedure was 2.2-fold greater in patients on aspirin at a dosage of at least 200 mg/day than in those on 100 mg/day or less.

“This analysis suggests low-dose aspirin may be superior with regard to a lower rate of serious bleeding compared to high-dose aspirin, and with similar efficacy in terms of death, MI, and stroke,” declared Dr. Jolly of McMaster University, Hamilton, Ont.

Moreover, these PCI-CURE findings are supported by two other large observational analyses in patients with acute coronary syndrome which reached the same conclusions. One, led by Dr. Eric J. Topol, involved nearly 9,200 participants in a study of the failed oral glycoprotein IIb/IIIa inhibitor lotrafiban (Circulation 2003;108:399-406). The other included more than 12,500 patients in a clopidogrel trial (Circulation 2003;108:1682-7).

“I personally have increasingly been prescribing low-dose aspirin after PCI because of the data from these three observational studies. However, I don't think we have the final word yet,” Dr. Jolly said.

He stressed that observational data such as these must be considered hypothesis generating. What's needed is a definitive, large, prospective, randomized clinical trial–and it so happens that such a study is well underway under the leadership of his colleagues at McMaster. The seventh Optimal Antiplatelet Strategy for Interventions/Clopidogrel Optimal Loading Dose Usage to Reduce Recurrent Events trial (OASIS-7/CURRENT) is randomizing 14,000 patients with unstable angina or non-ST-elevation MI to either a 300- or 600-mg loading dose of clopidogrel and low- or high-dose aspirin. Results should be available in 12-18 months.

The PCI-CURE analysis involved 2,658 patients with acute coronary syndrome on four continents who underwent PCI. Aspirin dosing was left to physician preference, which in Europe strongly favored the use of 100 mg/day or less in accord with the latest European Society of Cardiology practice guidelines. In contrast, the great majority of American cardiologists prescribed at least 200 mg/day–and most commonly 325 mg/day–as recommended in current American College of Cardiology/American Heart Association guidelines.

“I think when there's such a practice difference between Europeans and Americans, it tells us that perhaps we need more data,” the cardiologist observed.

At 8-month follow-up in PCI-CURE, the major bleeding rate was 1.9% in the low-dose aspirin group, compared with 3.9% with high-dose therapy. The 2.2-fold increased risk in the high-dose group was derived after adjusting for potential confounders, including age, gender, weight, hypertension, and use of clopidogrel versus placebo.

The combined end point of cardiovascular death, MI, or stroke was 7.1% in the low-dose aspirin group and 8.6% with high-dose therapy, a nonsignificant difference.

Dr. Paul A. Gurbel commented that he is deeply skeptical of a one-size-fits-all approach to antiplatelet therapy dosing in patients with CAD.

“Some patients will respond nicely to aspirin in a low dose and others won't, particularly the diabetic patients,” said Dr. Gurbel, director of the center for thrombosis research at Sinai Hospital and a cardiologist at Johns Hopkins University, both in Baltimore.

'I personally have increasingly been prescribing low-dose aspirin after PCI because of [these] data.' Dr. Jolly

'Some patients will respond nicely to aspirin in a low dose and others won't, particularly the diabetic patients.' DR. GURBEL

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