MedWire News: Further study of the HORIZON-AMI trial shows that of all patients given bivalirudin during primary percutaneous intervention (PCI), only those at high-risk for post-angioplasty complications may experience a reduction in 1-year mortality and myocardial infarction recurrence risk.
Initial reports of the Harmonizing Outcomes with RevasculariZatiON and Stents in Acute Myocardial Infarction (HORIZON-AMI) study reported significantly improved post-PCI outcomes with bivalirudin compared with unfractionated heparin (UFH) plus glycoprotein IIb/IIIa (GPI).
However a sub-analysis of the study has revealed that "the reduction in mortality was mainly driven by a difference in mortality in the high-risk patient group, whereas no difference could be revealed in the intermediate-risk group, and only a trend favoring bivalirudin was revealed in the low-risk group," say Guido Parodi (Careggi Hospital, Florence, Italy) and colleagues.
Parodi et al compared the post-PCI outcomes of 1522 low-risk, 531 intermediate-risk, and 477 high-risk acute myocardial infarction (AMI) patients randomly allocated to receive bivalirudin or UFH plus GPI during the procedure.
Low, intermediate, and high-risk patients were defined using the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) risk score.
The findings revealed that low- and high-risk patients given bivalirudin had lower 1-year mortality risks than those given UFH plus GPI, at 0.4% versus 1.2%, and 0.4% versus 15.9%, respectively.
However, this finding was only significant (p=0.01) for high-risk patients, the researchers report in the Journal of the American College of Cardiology.
Conversely, intermediate-risk patients given bivalirudin were found to have a nonsignificantly higher 1-year mortality risk than those given UFH plus GPI, at 4.2% versus 4.1%.
AMI recurrence also occurred at a significantly lower rate among high-risk patients taking bivalirudin than those taking UFH plus GPI, at 3.6% versus 7.6% (p=0.04).
In a related commentary, Fernando Alfonso and Manuel Paulo, from San Carlos University Hospital in Madrid, Spain, highlighted the shortcomings of the study, namely that "although the benefit found for high-risk patients was robust and unquestionable, no apparent efficacy benefit could be demonstrated for patients with low to intermediate risk who actually accounted for 81% of patients in the trial."
Alfonso and Paulo called for further studies to "elaborate on the potential value of bivalirudin in 'unselected' real-world patients with ST-elevation myocardial infarction."
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