NEW YORK (Reuters Health) – For patients with acute MI given early unfractionated heparin, a switch to bivalirudin before undergoing primary percutaneous coronary intervention results in improved cardiac survival, a multicenter team reports in the Journal of the American College of Cardiology for June 7.

The HORIZONS-AMI trial showed that bivalirudin rather than unfractionated heparin reduced major bleeding and mortality after PCI for ST-segment elevation MI, note Dr. George D. Dangas, with Mount Sinai Medical Center in New York, and colleagues.

However, unfractionated heparin is often administered initially in such cases, they point out. To see if a switch to bivalirudin before primary PCI is still worthwhile, the investigators looked at data from the HORIZON-AMI trial — in which randomization was stratified by pre-enrollment unfractionated heparin administration.

Among 2357 patients started on unfractionated heparin, 1178 were switched after enrollment to bivalirudin, according to the report, while a control group of 1179 patients continued on unfractionated heparin plus a glycoprotein IIb/IIIa inhibitor (GPI).

At 30 days, the rate of major bleeding was 7.6% in the switch group compared with 12.3% in the control group (p=0.0001), Dr. Dangas and colleagues found, and the rate of cardiac mortality was 1.6% vs 2.9%, respectively, (p=0.04).

Furthermore, at 2 years follow-up, major bleeding rates were 8.4% vs. 13.0% (p=0.0003) in the two groups, respectively, and cardiac mortality rates were 2.3% vs. 3.8% (p=0.04),

The authors conclude, “STEMI patients who receive early treatment with UFH (unfractionated heparin) may be safely switched to bivalirudin, a strategy that results in reduced hemorrhagic complications and cardiac mortality and enhanced event-free survival compared with UFH continuation and initiation of a GPI.”

J Am Coll Cardiol 2011;57:2309–2316.