Background: RE-DUAL PCI (NCT02164864) demonstrated reduced bleeding with dabigatran 110 mg and 150 mg bid dual antithrombotic therapy (DE-DAT) versus warfarin triple antithrombotic therapy (W-TAT) in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI). DE-DAT was non-inferior to W-TAT with respect to the risk of thromboembolic events. The Dual AntiPlatelet Therapy (DAPT) Study has shown that the angiographic lesion complexity, or clinical complexity – including acute coronary syndrome (ACS) presentation, were associated with increased risk of ischaemic events after PCI.

Aim: This subgroup analysis of RE-DUAL assessed the treatment effects on bleeding and thromboembolic outcomes according to the presence or absence of DAPT Study clinical and/or procedural lesion complexity factors.

Methods: Patients were randomized to receive W-TAT comprising warfarin, clopidogrel or ticagrelor, and aspirin, or DE-DAT comprising dabigatran 110 or 150 mg bid with clopidogrel or ticagrelor.

Patients were categorized according to the presence or absence of clinical or procedural complexity factors at baseline. The following were considered clinical complexity factors: ACS, acute ST-elevation myocardial infarction, renal insufficiency/failure and left ventricular ejection fraction <30%. The following were considered procedural/lesion-based complexity factors: >2 vessels stented, in-stent restenosis of a drug-eluting stent, prior brachytherapy, unprotected left main, >2 lesions per vessel, lesion length ≥30 mm, bifurcation lesion with side branch ≥2.5 mm, vein bypass graft, and thrombus-containing lesion.

The primary endpoint of ISTH major bleeding events (MBE) or clinically relevant non-major bleeding events (CRNMBE) and the composite efficacy endpoint of death or thromboembolic events (myocardial infarction, stroke or systemic embolism; DTE) or unplanned revascularization were compared for the three study arms in relation to the presence or absence of lesion complexity factors.

Results: A total of 2725 patients were randomized. At baseline, 37.0% of patients had neither clinical nor procedural complexity factors (Group I), 43.1% of patients had clinical complexity factors only (II), 9.9% of patients had procedural complexity factors only (III), and 10.0% of patients had both clinical and procedural complexity factors (IV).

The composite efficacy endpoint occurred in 11.7%, 14.5%, 13.3%, and 16.8% of subjects in group I, II, III, and IV. There was no significant interaction between complexity and the relative effects of treatment with DE-DAT vs W-TAT on ischaemic or bleeding outcomes (Figure).

Conclusion: In patients with AF who underwent PCI, the treatment effects of DE-DAT compared with W-TAT were consistent across the various subsets of clinical or procedural complexity, both for bleeding and ischaemic events.