Risk of early device-related thrombosis in post-Watchman cases on low-dose oral-anticoagulation versus dual-antiplatelet therapy

Objective We compared the risk of bleeding and early device-related thrombosis (DRT) events associated with low dose of non-vitamin K antagonist oral anticoagulants (LD-NOAC) vs dual antiplatelet therapy (DAPT) in post-left atrial appendage closure (LAAC) cases. Methods Based on the post-LAAC thromboprophylaxis, consecutive patients were categorized into DAPT group: aspirin+ clopidogrel for 6 months followed by aspirin 81 mg/day (n=501) or LD-NOAC group: low-dose of the non-vitamin K antagonist OAC (LD-NOAC) (n=917). Transesophageal echocardiography (TEE) was performed at 45 days and 3, 6 and 12-month post-procedure to exclude DRT. DRT were considered ‘early’ if they were detected within six months post-procedure. Patients on DAPT were propensity-matched with those on LD-NOAC with a 1:1.5 ratio, to control for confounding due to imbalance of covariates between groups. Results Real-world patients: DRT were detected in 21 (1.48%) patients; 15 (2.99%) and 6 (0.65%) patients in the DAPT and LD-NOAC cohort respectively (p=0.0005) All DRTs in the DAPT-group were detected by 3 months whereas it was detected at 6-mo TEE in 3 of the 6 (50%) patients of the LD-NOAC group Higher number of bleeding events were reported in the DAPT group (81 (16.2%) vs 79 (8.6%), p=0.001). Propensity-matched population: The matched population included 501 in the DAPT group and 751 patients in the LD-NOAC group (1: 1.5). DRT were detected in 13 (2.6%) vs 5 (0.7%) patients from the DAPT and LD-NOAC group respectively (p=0.005). In the multivariable model, DAPT (OR:3.921, 95% CI: 1.399-11.081, p=0.006) was an independent predictor of DRT. Conclusion DRT was detected in significantly higher number of real-world as well as matched patients that remained on DAPT vs LD-NOAC. DAPT was associated with >3 times higher risk of early DRT compared to LD-NOAC in propensity-matched populations Future randomized trials are needed to validate the current study findings