NEW YORK (Reuters Health) – In high-risk patients having percutaneous coronary intervention for ST-segment elevation acute myocardial infarction (STEMI), bivalirudin was more effective than unfractionated heparin plus a glycoprotein IIb/IIIa inhibitor (UFH/GPI) in reducing mortality and repeat myocardial infarction.
That’s according to a post hoc subgroup analysis of the randomized, open-label HORIZONS-AMI trial, reported in the August issue of JACC: Cardiovascular Interventions.
For high-risk STEMI patients, “bivalirudin appears to be not only safer but also more effective than standard antithrombotic strategies and, therefore, should be considered the preferred option,” say the authors of an editorial in the same issue.
The original HORIZONS-AMI analysis showed that patients treated with the direct thrombin inhibitor bivalirudin had less major bleeding, lower 30-day and 1-year mortality rates, and improvements in other cardiovascular outcomes compared to those in the UFH/GPI group.
For this report, first author Dr. Guido Parodi from Careggi Hospital, Florence, Italy, and colleagues stratified outcomes according to patients’ baseline risk. Out of a total 3602 patients, they were able to classify 2530 by the CADILLAC risk score: 1522 as low-risk, 531 as intermediate risk, and 477 as high risk.
One-year mortality rates in the bivalirudin and the UFH/GPI arms did not differ significantly in the low-risk group (0.4% vs 1.2%, respectively; p = 0.09) or in the intermediate-risk group (4.2% vs 4.1%, respectively; p = 0.99).
But bivalirudin nearly cut mortality in half in the high-risk group (8.4% vs 15.9%, p = 0.01).
Except for a lower rate of recurrent MI in high-risk patients assigned to bivalirudin (3.6% vs 7.9%, p = 0.042), the authors observed no other significant differences in nonfatal ischemic events between the two treatment arms.
Randomization to bivalirudin reduced major bleeding rates, which reached significance in the low-risk group.
These results “support bivalirudin treatment as a standard of care for high-risk patients undergoing primary PCI for acute myocardial infarction,” the authors say.
Still, they acknowledge, the analysis can only be considered hypothesis-generating, since it was not pre-specified. Also, almost 30% of the original cohort could not be classified by the CADILLAC score, primarily because they could not undergo angiography.
In an editorial, Dr. Fernando Alfonso and Dr. Manuel Paulo, from San Carlos University Hospital, Madrid say that because the 81% of patients who were at low to intermediate risk showed no benefit from bivalirudin, “further studies should elaborate on the potential value of bivalirudin in ‘unselected’ real world patients with STEMI.”
The editorialists also point out the potential for bias or chance findings in the highly selected high-risk patients.
They recommend studies to determine the long-term cost-effectiveness of bivalirudin in high-risk patients.
Nevertheless, Drs. Alfonso and Paulo conclude, this study “provides scientifically valuable, novel, and unique insights that help to further refine interventions in high-risk patients with STEMI.”
The HORIZONS-AMI trial was supported by Boston Scientific Corporation and The Medicines Company (Parsippany, New Jersey), which sells bivalirudin under the brand name Angiomax. Several of the authors receive funding from these companies.
Impact of Bivalirudin Therapy in High-Risk Patients With Acute Myocardial Infarction
J Am Coll Cardiol Intv 2010;3:796-802,803-805.