Massive Device-Related Thrombus After Left Atrial Appendage Closure in Kidney Transplant Recipient With Hypertrophic Cardiomyopathy

BACKGROUND: Although left atrial appendage closure (LAAC) provides a crucial stroke prevention alternative for patients with atrial fibrillation (AF) who cannot undergo long-term anticoagulation, concurrent hypertrophic cardiomyopathy (HCM) elevates the risk of device-related thrombosis (DRT) after the procedure. CASE SUMMARY: This case report describes a 59-year-old woman with HCM, permanent AF, and a history of renal transplantation. Stroke prophylaxis was performed via LAAC with a 33-mm Watchman device. Premature discontinuation of dual-antiplatelet therapy 1 month postprocedure led to a large (5.2 cm × 2.5 cm) DRT identified at 6-month follow-up. The thrombus resolved completely after a prolonged, staged, and dose-adjusted course of rivaroxaban. DISCUSSION: The efficacy and safety of LAAC for stroke prevention in patients with HCM and AF who cannot tolerate anticoagulation remain debated TAKE-HOME MESSAGE: Although LAAC is not a standard stroke prevention therapy for HCM patients with AF, it represents a viable alternative in high-bleeding-risk scenarios and requires meticulous planning, vigilant DRT surveillance, and individualized antithrombotic management.