Antithrombotic therapy and device healing after left atrial appendage occlusion with WATCHMAN FLX Pro: a single-center real-world cohort study.

M. Nikoo R. Feroze L. P. Dallan Yusef Saeed Alexander Cove Abdullah Altorbag Andreas A. Towers Syed R. Nabi Harsh Amin Sabin Lama Christopher Mishreky Kareem Fanous Justin M. Dunn V. Esteves S. Filby

Sep 2026 · The Journal of invasive cardiology · 0 citations

Medicine

Abstract

Objectives

The authors sought to determine whether discharge antithrombotic regimen (dual antiplatelet therapy [DAPT] vs low-dose direct oral anticoagulant [DOAC] monotherapy) is independently associated with computed tomography (CT)-detected high-grade hypoattenuated thickening (HAT), an imaging correlate of device-related thrombus, and with early clinical outcomes following WATCHMAN FLX Pro (Boston Scientific) implantation.

Methods

A single-center retrospective analysis of 427 consecutive patients undergoing attempted WATCHMAN FLX Pro implantation (July 2024-October 2025) was conducted. After excluding 10 patients with screen failure and 17 on alternative antithrombotic regimens, 400 patients (263 DAPT, 137 low-dose DOAC) were included. The primary endpoint was high-grade HAT on 4-month surveillance cardiac CT. Secondary endpoints were appendage patency, peridevice leak (PDL), incomplete neoendocardial coverage, and 180-day clinical outcomes.

Results

Surveillance CT was performed in 322 of 400 patients (80.5%). High-grade HAT occurred in 12/213 patients on DAPT (5.6%) vs 1/109 patients on DOAC (0.9%; P = .046); 92.3% of high-grade HAT cases were in the DAPT group. DAPT remained independently associated with high-grade HAT on multivariable analysis (adjusted odds ratio, 7.43; 95% CI, 1.01-54.44; P = .048). Appendage patency, PDL, and incomplete neoendocardial coverage were similar between groups. Through 180 days, stroke, bleeding, and mortality did not differ significantly by regimen.

Conclusions

In this real-world WATCHMAN FLX Pro cohort, low-dose DOAC monotherapy was associated with a markedly lower risk of CT-detected high-grade HAT than DAPT, without an observed increase in bleeding or stroke. Anticoagulation during the early post-implant healing period may mitigate thrombus formation more effectively than antiplatelet therapy. Randomized trials are needed to confirm these findings.

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