Rivaroxaban plus antiplatelet therapy for coronary artery ectasia: 36-month outcomes and risk prediction from a retrospective cohort study
Background Coronary artery ectasia (CAE) is characterized by abnormal coronary dilation and slow flow, predisposing patients to thrombotic complications. Optimal long-term antithrombotic strategies for CAE remain undefined. This study aimed to evaluate the efficacy and safety of low-dose rivaroxaban combined with single antiplatelet therapy in patients with CAE. Methods In this single-center retrospective cohort study, 312 patients with CAE were enrolled and followed for 36 months. Patients received either single antiplatelet therapy alone or in combination with low-dose rivaroxaban. Propensity score matching (1:1) was performed to balance baseline characteristics. The primary endpoint was major adverse cardiovascular events (MACE). Secondary analyses included changes in thrombotic, inflammatory, and myocardial injury biomarkers. Cox proportional hazards models, inverse probability weighting, competing risk models, and sensitivity analyses were conducted to assess robustness. Results After propensity score matching (124 vs. 124), combination therapy was associated with a significantly lower risk of 36-month MACE compared with antiplatelet therapy alone (8.1% vs. 21.8%; HR = 0.34, 95% CI: 0.19–0.62; P < 0.001), corresponding to an absolute risk reduction of 13.7% and a number needed to treat of 7.3. The benefit was more pronounced in patients with diffuse ectasia (Markis I/II: HR = 0.21, 95% CI: 0.09–0.49; interaction P = 0.02) and elevated baseline D-dimer (≥0.8 mg/L: HR = 0.18, 95% CI: 0.08–0.41; interaction P = 0.01). Improvements in D-dimer, inflammatory markers, and myocardial injury biomarkers were greater in the combination group. Total bleeding rates were not significantly different between groups, and no fatal bleeding occurred. Net clinical benefit favored combination therapy. Results remained consistent across multiple sensitivity analyses. A simple risk prediction model based on D-dimer, Markis classification, and treatment regimen was developed in the same cohort (C-index 0.78) but has not been externally validated. Conclusions In patients with CAE, low-dose rivaroxaban combined with single antiplatelet therapy was associated with lower long-term MACE risk without a significant increase in major bleeding. The benefit appeared particularly pronounced in patients with diffuse ectasia and higher thrombotic burden. The simple predictive model based on D-dimer, Markis classification, and treatment regimen may aid in individualized antithrombotic decision-making, but requires external validation.