NEW YORK (Reuters Health) – In patients undergoing percutaneous coronary intervention (PCI) for non-ST-segment elevation myocardial infarction, delaying clopidogrel loading until just before or after PCI does not appear to worsen outcomes compared with the standard approach of giving the drug before angiography, new research shows.

“As long as patients are taken to the cath lab within 12-24 hours of their presentation with non-ST-segment elevation ACS, they can receive a high dose (600 mg) of clopidogrel after coronary angiography and have similar rates of cardiovascular events compared to the currently recommended clopidogrel pretreatment regimen,” Dr. Dimitriy N. Feldman from Weill Cornell Medical College, New York told Reuters Health in an email.

In a retrospective study, Dr. Feldman’s team evaluated the safety and efficacy of high-dose clopidogrel given in the cath lab within 2 hours before or 30 minutes after PCI, compared with preangiography clopidogrel. Overall, the study involved 1041 patients: 574 received in-lab loading doses and 467 were treated according to standard protocols. The findings are reported in the December 23rd online issue of the American Journal of Cardiology.

Rates of angiographic success, overall mortality, in-hospital myocardial infarction, and major adverse coronary events (MACE) were similar with the two approaches, the authors report.

The incidence of major and minor bleeding complications was also similar after preangiography treatment and in-lab treatment.

The lack of any difference persisted when the authors looked only at high-risk patients who had troponin I elevations at presentation.

Among patients who received bivalirudin during PCI, however, in-lab clopidogrel loading was associated with a higher rate of myocardial infarction (8.1% vs 3.7%) a trend toward an increase in major adverse coronary events (8.5% vs 4.8%). These differences, however, were limited to patients with creatine kinase-MB elevations between 3 and 5 times the upper limit of normal.

Both clopidogrel treatment groups had 18 deaths at 1 year, and the all-cause mortality at the end of follow-up (mean, 23.8 months) was similar in patients treated with clopidogrel before angiography (31 deaths, 6.6%) or in the catheterization laboratory (24 deaths, 4.2%).

“Although the data in this analysis is collected prospectively, this was a retrospective analysis, and a randomized trial would be needed to conclusively demonstrate that treatment with a 600-mg loading dose <2 hours pre-PCI is associated with similar short-term ischemic outcomes when compared to currently recommended clopidogrel pretreatment regimen,” Dr. Feldman said.

Am J Cardiol 2010.