A novel risk score to identify the need for triple antithrombotic therapy in patients with atrial fibrillation undergoing percutaneous coronary intervention: a post hoc analysis of the RE-DUAL PCI trial.

Background: Current guidelines recommend treating atrial fibrillation (AF) patients who undergo percutaneous coronary intervention (PCI) with triple antithrombotic therapy (TAT) for up to one month in patients at high thrombotic risk. It is unclear how to select these high-risk patients.

Aims: The aim of this study was to identify patients at high thrombotic risk who might benefit from TAT over double antithrombotic therapy (DAT).

Methods: This study was a post hoc subanalysis of the RE-DUAL PCI trial. A Cox proportional hazards model was built by stepwise selection of plausible predictor variables for a composite ischaemic endpoint, defined as cardiovascular death, myocardial infarction (MI), stent thrombosis (ST) or ischaemic stroke. The effect of TAT versus DAT was calculated for those patients with the highest proportion of predicted thrombotic risk. A simplified risk score was constructed based on beta-coefficients.

Results: For 209 patients (7.7%) the composite ischaemic endpoint occurred during the first year. The simplified risk score contained six variables. In patients with a score ≥5 (n=154, 5.7%), a significant reduction in the composite of MI and ST was observed with TAT versus DAT (6.3% vs 21.0%, p=0.041), without a penalty in terms of bleeding. In patients at low thrombotic risk, a significant increase in bleeding was observed without a reduction of ischaemic events.

Conclusions: Our findings support the use of DAT in the majority of patients. A small subgroup of patients might benefit from TAT and we propose a novel clinical risk score to select these patients.