Dual antiplatelet therapy (DAPT) after left atrial appendage occlusion (LAAO) using the Watchman FLX (Boston Scientific) device was comparable in terms of rates of death, stroke, bleeding or device-related thrombus when compared to use of aspirin with an anticoagulant, warfarin or direct oral anticoagulant (DOAC), analysis of registry data has shown.
These were among the insights presented by Megan Coylewright (Director of Structural Heart, Erlanger Health System, Chattanooga, USA) during a late-breaking trial session at TVT 2022 (The Structural Heart Summit, 8–10 June, Chicago, USA), where she delivered findings of the DAPT FLX study, comparing effectiveness of post-procedural medications following LAAO.
Patients with atrial fibrillation (AF) have a heightened risk of stroke, Coylewright told TVT attendees, noting that the most common source of clots is the left atrial appendage. Many patients, she said, have an “appropriate rationale” to avoid long-term anticoagulation. Watchman is indicated to reduce the risk of thromboembolism from the left atrial appendage in patients with non-valvular atrial fibrillation who are at increased risk for stroke and systemic embolism.
Current on-label, post-procedure regimen after Watchman FLX includes 45 days of aspirin with an anticoagulant, warfarin or DOAC, Coylewright detailed in her presentation, commenting: “We see barriers to referral for left atrial appendage occlusion for fear of the 45-day requirement of anticoagulation after procedure.”
The study presented at TVT, which analysed patients from the National Cardiovascular Disease LAAO Registry (NCDR), sought to evaluate if DAPT is a safe alternative option.
“If we are choosing not to use the FDA-approved regimen post-Watchman, then the patients are probably different,” Coylewright commented, noting that this was reflected in the baseline characteristics of the patients, with those who were discharged on DAPT typically being older, having more vascular or coronary disease, prior stroke, or major bleeding.
Coylewright reported that adjusted outcomes from discharge to 45 days with regards to the differences between DAPT and DOAC plus aspirin, showed the composite endpoint of death, stroke and major bleeding occurred in 2.9% of DAPT patients and 3.3% in the DOAC plus aspirin group. There was no significant difference in the rate of device-related thrombus in each group, she noted.
Comparing DAPT with warfarin plus aspirin, Coylewright again reported that there was no significant difference in the composite endpoint, which reached 2.8% for the DAPT group and 3% in the warfarin plus aspirin cohort. Additionally, there was no significant difference in device related thrombus, which remained low in both groups.
Noting some of the limitations of the study, Coylewright commented that the use of a variety of post-procedure medication regimens as seen in the registry data, indicates that physicians are already individualising their approach to the risks of device related thrombus and stroke and bleeding risks, despite the currently approved indications. “Propensity matching, thus, cannot adjust for all of the differences inherent in physicians already selecting patients for one therapy over another,” she remarked.
Summing up the findings, Coylewright remarked that the DAPT FLX study shows no difference in death, stroke, bleeding or device-related thrombus between a post-procedure medication regimen of DAPT versus DOAC or warfarin plus aspirin at 45 days with Watchman FLX.