Individual risk profiling of ACS patients may optimize antithrombotic management
MedWire News: Considering the individual risk profiles of patients with acute coronary syndrome (ACS) and weighing their risk for bleeding complications against their potential benefit from antithrombotic treatment could optimize their therapeutic management, say researchers.
By assessing the individual risk profile for myocardial infarction (MI) and major bleeding unrelated to coronary artery bypass graft (CABG), and the relative risk for these events with alternative antithrombotic strategies, “a personalized selection of the optimal pharmacologic regimen for the individual patient can be made that would be expected to minimize the occurrence of MI and major bleeding and their impact on subsequent risk of death,” the team reports in the journal Circulation.
Stuart Pocock (London School of Hygiene and Tropical Medicine, UK) and co-workers analyzed data from the ACUITY (Acute Catheterization and Urgent Intervention Triage Strategy) trial to identify risk factors for MI and major (non-CABG) bleeding complications.
The trial included 13,819 patients with non-ST-segment elevation ACS who were randomly assigned to receive standard treatment with heparin and a glycoprotein (GP) IIb/IIIa inhibitor, bivalirudin and a GP IIb/IIIa inhibitor, or bivalirudin alone.
Using logistic regression analysis, they found that risk factors for MI and non-CABG bleeding differed substantially, with only ST-segment deviation and older age independent predictors of both outcomes.
For MI, other predictors were elevated cardiac biomarkers, family history of coronary artery disease, and previous MI, while six additional predictors of non-CABG related major bleeding were female gender, baseline anemia, elevated serum creatinine, elevated white blood cell count, previous PCI, randomization to heparin and GP IIb/IIIa inhibitor versus bivalirudin alone, and heparin plus upstream, routine rather than deferred GP IIb/IIIa inhibitor.
Treatment with bivalirudin alone versus heparin plus a GP IIb/IIIa inhibitor was associated with a nonsignificant trend for an 8% increase in MI risk, offset by a highly significant 50% decrease in major bleeding. This would indicate that at least around six major bleeds would be prevented for each additional MI that might occur by choosing bivalirudin over the standard treatment.
“One can then estimate for each individual patient the absolute reduction in bleeding risk and the absolute increase in MI risk,” explain Pocock and team.
In this trial, “for the overwhelming majority of patients, the estimated reduction in bleeding risk is greater than the estimated increase in MI risk,” they add.
Further analysis demonstrated that both MI and major bleeding were associated with significantly increased mortality rates, at hazard ratios of 2.7 and 2.9, respectively (both p<0.001).
Commenting on the analysis, Frans van der Werf pointed out in a related editorial that, as nearly all patients with ACS have to have anticoagulant treatment combined with antiplatelet agents in the acute phase, the benefit-to-risk ratio of any anticoagulant such as bivalirudin has to be evaluated on the background of antiplatelet therapy.
Bleeding risks and risk factors may differ with these different types of agent, he explained, and it would be interesting if similar analyses could be performed with available data from large studies of P2Y12 inhibitors in ACS.
He urged investigators to apply established bleeding and MI definitions consistently in future trial, so that such analyses “may pave the way for the development of a clinically useful combined benefit-to-risk score and therefore to a more personalized antithrombotic treatment for ACS patients.”
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By Caroline Price