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Tirofiban Improves Outcomes After Elective Percutaneous Coronary Intervention in Patients Resistant to Aspirin or Clopidogrel: Presented at ESC

By Chris Berrie

MUNICH, Germany -- September 4, 2008 -- Infusion of the potent antiplatelet agent tirofiban decreases the risk of myocardial infarction (MI) and major adverse cardiovascular events following elective percutaneous coronary intervention (PCI) in patients with coronary artery disease (CAD) who show poor response to aspirin and/or clopidogrel, according to a prospective, randomised, placebo-controlled study.

Results were presented by principal investigator Marco Valgimigli, MD, PhD, Department of Cardiology, University of Ferrara, Ferrara, Italy, here at the European Society of Cardiology 2008 Congress (ESC) on behalf of the Tailoring Treatment with Tirofiban in Patients Showing Resistance to Aspirin or Resistance to Clopidogrel (3T/2R) study investigators.

"Many previous studies showed that poor response to aspirin or clopidogrel [in patients with CAD] increases up to 10 times the risk of thrombotic events, particularly after PCI," Dr. Valgimigli said during his presentation on September 2.

His research team therefore screened patients who were scheduled to undergo elective coronary angiography for silent ischaemia, stable angina, or low-risk non-ST elevation acute coronary syndrome.

The study enrolled patients undergoing PCI who were persistently negative for the cardiac markers creatine kinase (CK), CK myocardial branch (CK-MB), and troponin I/T. Patients also had no contraindications to glycoprotein IIb/IIIa blockers and had poor responses to aspirin and/or clopidogrel therapy.

After screening 994 patients for aspirin and/or clopidogrel response and satisfaction of eligibility, the researchers randomised 116 poor responders to aspirin and 147 poor responders to clopidogrel to infusion with placebo (52 and 79, respectively) or tirofiban (64 and 68, respectively).

Placebo was provided on top of standard aspirin/clopidogrel, and tirofiban infusion was at 25 mcg/kg over 3 minutes followed by infusion at 0.15 mcg/kg/minute for 14 to 24 hours.

The primary endpoint was troponin I, T elevation >3 times the upper limit of normal (ULN) in 1 or more blood samples within 48 hours after PCI. Secondary endpoints were stratified CK-MB mass elevation (>1x, >3x, >5x ULN) as well as major adverse cardiovascular events and stent thrombosis at 30 days.

There were no significant differences in baseline clinical characteristics or PCI procedures between the 131 patients in the placebo group (mean age, 69 years; male, 72.5%) and the 132 patients in the tirofiban group (mean age, 69 years; male, 74.2%).

For the primary endpoint, tirofiban showed a significant reduction over placebo (20.4% vs 35.1%, respectively; P = .009), with a relative risk reduction of 42% for tirofiban. "This result importantly proved to be consistent across many prespecified subgroups," Dr. Valgimigli noted.

For CK-MB elevation, a significant reduction in relative risk over placebo was seen at >1x ULN (62%; P < .001), with beneficial trends at >3x (50%; P = .09) and 5x (70%; P = .05) ULN.

The secondary major adverse cardiovascular events and thrombosis endpoint showed significant reduction with tirofiban treatment over placebo (21% vs 37%, respectively; P = .006), which Dr. Valgimigli noted was entirely driven by the decrease in MI. There were no significant differences in safety endpoints.

"Our study may provide proof of concept for a new treatment strategy in patients with coronary artery disease," Dr. Valgimigli concluded.

Funding for this study was partially provided by Merck & Co. and Iroko Pharmaceuticals.


[Presentation title: Main Results of the Tailoring Treatment With Tirofiban in Patients Showing Resistance to Aspirin or Resistance to Clopidogrel Study (3T/2R). Abstract 3210]

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