Patients could benefit from being given dual antiplatelet therapy for up to three years after a heart attack, research suggests.
A US study found patients who were given the antiplatelet ticagrelor on top of standard, low-dose aspirin therapy for three years had a statistically significant reduction in heart disease deaths and complications compared with those on aspirin alone.
Researchers compared ticagrelor – at two different doses, 60mg or 90mg twice daily – with placebo in a study of over 21,000 patients who had recently had a heart attack, all of whom were taking low-dose aspirin.
They found ticagrelor at both doses resulted in around a relative 15% reduction in the risk of cardiovascular death, MI or stroke at three years, compared with placebo.
However, ticagrelor also significantly increased the risk of major bleeding, from 1.0% to around 2.5% – although the authors said rates of bleeding that led to severe or irreversible harm were less than 1% for all three groups.
Current NICE guidelines recommend dual antiplatelet therapy – with either clopidogel or ticagrelor on top of aspirin – for up to a year post-MI, but whether it is benefits of longer-term dual therapy outweigh the harms remains unclear.
The researchers said their study provides the first ‘prospectively defined evidence affirming the hypothesis that long-term, intensive platelet inhibition… reduces ischaemic events in patients with prior myocardial infarction’.
Given there were fewer discontinuations at the lower ticagrelor dose the team added that the ‘60-mg dose may offer a more attractive benefit-risk profile’.
However, a related editorial pointed out that at this lower dose, treating 10,000 patients for a year would prevent 42 primary endpoint events and cause 31 major bleeding events, a risk-benefit profile described as ‘close to an even proposition’.
NEJM 2015; available online 7 May
