Abstract 13940: Intra-Operative Findings With Massive Device-Related Thrombus After Percutaneous LAA Closure: Mechanistic Insights

Abstract

Background: Device related thrombus (DRT) has an observed incidence of ~4% after left atrial appendage closure (LAAC), of which the mechanism remains incompletely understood. Objective: To present and examine the intraoperative findings of 2 cases of massive DRT occurring late post LAAC device implantation and propose potential mechanisms for these rare complications. Methods: N/A Results: Patient 1 was a 75-year-old female with paroxysmal AF and CHA2DS2-VASc Score of 5 with Watchman implanted two years prior to presentation. She had completed 45 days of warfarin and ASA after implantation. She underwent elective open heart surgery for severe mitral valve regurgitation and moderate to severe aortic valve regurgitation. Large DRT (2x2cm) was diagnosed intraoperatively, which was treated with left atrial appendage and device resection. Patient 2 was a 75-year-old female with permanent AF and CHA2DS2-VASc Score of 5, who was referred for routine postimplant surveillance TEE. She had also completed 45 days of warfarin and ASA after implantation. A large DRT measuring 2 x 2 cm was noted. The patient was treated with warfarin and subsequently dabigatran with improvement in the size of thrombus on TEE. However, a gastrointestinal bleed led to the cessation of anticoagulation. Subsequent TEE demonstrated enlargement of massive DRT (3x2 cm). She was referred to cardiac surgery for thrombectomy and resection of the Watchman device and LAA. Discussion/Conclusion: In both cases, the intraoperative findings demonstrate well-seated LAAC without gross findings of malapposition or peri-device leaks. The central screw was visible without evidence of endothelialization in both cases (Figure 1). An exposed central screw could be a possible nidus for thrombus formation.