Prasugrel Bests Double Clopidogrel Dose for STEMI Patients with High Residual Platelet Reactivity
SAN FRANCISO, CA—Patients with ST-segment elevation myocardial infarction (STEMI) who show early high on-treatment platelet reactivity achieve greater platelet inhibition with the addition of a 60-mg loading dose of prasugrel followed by a 10-mg maintenance than from a double maintenance dose of clopidogrel, according to data presented November 9, 2011, at the annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium.
In a prospective single-center study led by Dimitrios Alexopoulos, MD, PhD, of Patras University Hospital (Patras, Greece), 60 of 93 eligible patients undergoing primary PCI demonstrated high on-treatment platelet reactivity (PRU ≥ 235) 2 hours after receiving a 600-mg loading dose of clopidogrel. The investigators randomized these patients to immediate reloading with 60 mg of prasugrel followed by a 10-mg maintenance dose (n=31) or a 150-mg maintenance dose of clopidogrel (n=29) starting the next day.
Platelet reactivity was significantly lower in the prasugrel arm compared with the clopidogrel arm at 2 hours, 24 hours, and 5 days (Figure 1). As expected, CYP2C19*2 loss-of-function carriers responded less to the new regimens than did noncarriers. Nonetheless, at 24 hours prasugrel produced a significant reduction in platelet reactivity compared with clopidogrel in carriers (Figure 2).
“In the case of high on-treatment platelet reactivity at 2 hours after clopidogrel loading dose, an additional 60-mg loading dose of prasugrel administered with a subsequent 10-mg maintenance dose will provide faster and stronger platelet inhibition than a high clopidogrel maintenance-dose regimen,” Dr. Alexopoulos said. “Whether tailoring of antiplatelet treatment in STEMI patients exhibiting early high on-treatment platelet reactivity is clinically useful should be further explored.”
Study Details
All patients received a 600-mg loading dose of clopidogrel with 325 mg of aspirin at first medical contact and a bolus of 70 IU/kg of unfractionated heparin intravenously.
Platelet function was measured via peripheral venous blood sampling 2 hours after clopidogrel loading with the VerifyNow point-of-care assay (Accumetrics, San Diego, CA).
Source:
Alexopoulos D. A prospective, randomized trial of prasugrel vs. double-dose clopidogrel in patients with ST-segment elevation myocardial infarction and clopidogrel hyporesponsiveness. Presented at: Transcatheter Cardiovascular Therapeutics 2011; November 9, 2011; San Francisco, CA.
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Disclosures
- Dr. Alexopoulos reports no relevant conflicts of interest.
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