Device-associated thrombus after percutaneous left atrial appendage closure: a case report and literature review

Abstract

Introduction. In the setting of atrial fibrillation (AF), left atrial appendage (LAA) closure using the Watchman^TM device (WD) was proven to effectively prevent stroke, systemic embolism and cardiovascular death when compared with warfarin therapy. However, this procedure is potentially associated with the risk of complications, including device-attached thrombus formation.

Case presentation. We report a case of a 65-year-old woman with permanent non-valvular AF, a history of ischemic stroke on warfarin treatment, hypertension, diabetes mellitus, heart failure with preserved left ventricular ejection fraction, labile values of the international normalized ratio, enlarged left atrium (LA) and spontaneous echo contrast in echocardiography, who was qualified for percutaneous LAA closure using the WD. The pre-procedural patient assessment indicated high thromboembolic (CHA₂DS₂-Vasc Score = 5) and bleeding risk (HAS-BLED Score = 4), and optimal morphology of LAA in transesophageal echocardiography (TEE). After a successful procedure using a 30 mm-sized WD, and despite appropriate antiplatelet and anticoagulation therapy, 6-month follow-up TEE revealed a mobile thrombus (2.4 cm × 0.6 cm) at the atrial side of the WD. Therapy with intravenous heparin was started. However, a control TEE examination after one week revealed progression of the thrombus size (4.2 cm × 0.7 cm) and its protrusion across the mitral valve orifice into the left ventricle. Although the patient remained asymptomatic, cardiosurgical excision of the thrombus was performed due to high risk of thrombus embolization.

Conclusions. Late device-associated thrombus formation after implantation of the WD remains a rare but severe complication. Formal recommendations regarding prevention and management of device-related thrombosis are still lacking. In this complex clinical setting, we suggest: 1) careful long-term echocardiographic monitoring after percutaneous LAA closure, especially in patients with permanent AF, high thromboembolic risk, large LA and dense spontaneous echo contrast in echocardiography, and 2) an individualized treatment approach.