Impact of the Type of Anticoagulation Therapy on Long-Term Clinical Outcomes in Patients with Coronary Bifurcation Lesion and Atrial Fibrillation—Insights from the Bulgarian Bifurcation Registry

<i>Background and Objectives</i>: Patients with atrial fibrillation and coronary artery disease represent a group with a greater risk of mortality. To evaluate patients with atrial fibrillation (AF) and a significant coronary bifurcation lesion and compare the clinical outcomes between the patients on anticoagulant treatment with Vitamin K antagonist (VKA) and those on direct anticoagulant (DOAC). <i>Materials and Methods</i>: This is a prospective study of patients with AF and stable coronary artery disease, who had evidence of a significant coronary bifurcation lesion. A log-rank test was used to assess the difference in mortality between patients taking VKA and those on DOAC. The primary endpoint was the incidence of all-cause and cardiovascular death at mid-term. <i>Results</i>: A total of 226 patients with AF and a significant bifurcation lesion were included. The mean age was 70.9 ± 9.2, and 70% were males. Of the patients, 123 (54.7%) were on VKA treatment, and 103 (45.3%) were taking DOAC. For a median follow-up time of 55 (39-96) months, overall mortality was 40%, whereas CV mortality was 31%. Both all-cause (28.2% versus 50.4%, <i>p</i> = 0.020) and CV death (12.7% versus 24.9%, <i>p</i> = 0.032) were significantly lower in patients taking DOAC versus those on VKA. In patients treated with PCI, CV mortality was significantly lower in patients taking DOAC (21.4% versus 40.5%, <i>p</i> = 0.032). VKA therapy was an independent predictor of cardiovascular death (HR 1.88; 95% CI 1.11-3.18; <i>p</i> = 0.01), together with chronic kidney disease (HR 1.81; 95% CI 1.13-2.92; <i>p</i> = 0.01). <i>Conclusions</i>: Treatment with DOAC in patients with atrial fibrillation and coronary bifurcation lesion was associated with significantly lower mortality independently of the treatment approach. VKA was an independent predictor of CV mortality.