Antithrombotic therapies are commonly recommended for patients with atrial fibrillation (AFib), just as dual antiplatelet therapy (DAPT) is suggested for patients following percutaneous coronary intervention (PCI). But when DAPT is added on top of an oral anticoagulant, is there a risk of overdoing the blood thinners?
A new meta-analysis in the European Heart Journal suggests there is, as AFib patients who received dual antithrombotic therapy (DAT) after PCI demonstrated a 47 percent reduction in bleeding events when compared to those who took three blood thinners. The rates of major adverse cardiac events (MACE) were similar between groups.
“These findings have significant clinical implications, as bleeding is associated with interruption of antithrombotic therapy which in turn is associated with MACE,” wrote senior author Deepak L. Bhatt, MD, MPH, and colleagues. “Furthermore, intracranial bleeding, one of the most dreadful and feared complications of TAT (triple antithrombotic therapy), showed a strong numerical trend towards reduction with DAT, particularly driven by patients enrolled in trials evaluating NOACs (non-vitamin K antagonist oral anticoagulants). This finding is crucial for management of patients at high risk of bleeding in which TAT may carry an even higher risk.”
Bhatt and coauthors pooled data from four trials including 5,317 patients, 57 percent of whom received DAT after PCI. Bleeding rates were 4.3 percent versus 9.0 percent for double therapy and triple therapy, respectively. The risk of intracranial bleeding was 42 percent lower in the DAT group, although the difference didn’t reach statistical significance.
While more intensive antithrombotic therapy would be expected raise the risk of bleeding, MACE from fewer clot-related events is a perceived benefit of TAT, Bhatt and colleagues wrote. In fact, this approach has been endorsed in both American and European cardiology guidelines.
But DAT appeared to be equally effective at preventing MACE in this meta-analysis. Although they couldn’t specify the reasons for this parity, the authors ventured a couple of explanations aside from the aforementioned point about bleeding events interrupting therapy.
“Newer generation drug-eluting stents with extremely low (less than 1 percent) incidence of stent thrombosis may have played a role,” they wrote. “In addition, clopidogrel on a biological basis has more platelet inhibition compared with aspirin with less gastrointestinal bleeding which could in combination with OAC avoid the need for aspirin. This hypothesis has been supported by two randomized trials which demonstrated that OAC is equivalent (or even better) than aspirin for protection against thrombotic events.”
Bhatt et al. said it now becomes important to investigate which specific combinations of DAT best balance thromboembolic and bleeding risks.
“With several such combinations possible, future trials are needed to answer these critical questions,” the researchers noted.
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.