A History of Left Atrial Appendage Occlusion.

A new era in antiembolic therapy has been initiated by the growing numbers of device-based therapies. Early concerns surrounding eliminating this enigmatic structure have not proven true. Other benefits are being further evaluated. Many other questions remain, such as whether there is a device-specific outcome effect or whether it is a class effect. Other questions include other devices, what head-to-head studies will show, and the impact of residual leak. Left atrial appendage using the Watchman ablation strategy can reduce cardioembolic stroke, with comparable or fewer adverse effects by device technology than obtained by long-term anticoagulation with its attendant bleeding risks.

Assessment of Device-Related Thrombus and Associated Clinical Outcomes With the WATCHMAN Left Atrial Appendage Closure Device for Embolic Protection in Patients With Atrial Fibrillation (from the PROTECT-AF Trial).

Left atrial appendage closure with the WATCHMAN device is an alternative to anticoagulation for stroke prevention in selected patients with atrial fibrillation (AF). LA device-related thrombus (DRT) is poorly defined and understood. We aimed to (1) develop consensus echocardiographic diagnostic criteria for DRT; (2) estimate the incidence of DRT; and (3) determine clinical event rates in patients with DRT. In phase 1 (training), a training manual was developed and reviewed by 3 echocardiographers with left atrial appendage closure device experience. All available transesophageal (TEE) studies in the WATCHMAN left atrial appendage system for embolic protection in patients with atrial fibrillation (PROTECT-AF) trial patients with suspected DRT were reviewed in 2 subsequent phases. In phase 2 (primary blind read), each reviewer independently scored each study for DRT, and final echo criteria were developed. Unanimously scored studies were considered adjudicated, whereas all others were reevaluated by all reviewers in phase 3 (group adjudication read). DRT was suspected in 35 of 485 patients by the site investigator, the echocardiography core laboratory, or both; 93 of the individual TEE studies were available for review. In phase 2, 3 readers agreed on 67 (72%) of time points. Based on phases 1 and 2, 5 DRT criteria were developed. In phase 3, studies without agreement in phase 2 were adjudicated using these criteria. Overall, at least 1 TEE was DRT positive in 27 (5.7%) PROTECT-AF patients. Stroke, peripheral embolism, or cardiac/unexplained death occurred in subjects with DRT at a rate of 3.4 per 100 patient-years follow-up. In conclusion, DRT were identified on at least 1 TEE in 27 PROTECT-AF patients, indicating a DRT incidence of 5.7%. Primary efficacy events in patients with DRT occurred at a rate of 3.4 per 100 patient-years follow-up, intermediate in frequency between event rates previously reported for the overall device and warfarin arms in PROTECT-AF.

Resolution (and Late Recurrence) of WATCHMAN Device-Related Thrombus Following Treatment with Dabigatran.

The WATCHMAN left atrial (LA) appendage closure system is an alternative therapy for stroke prevention in patients with atrial fibrillation who are intolerant to chronic oral anticoagulation with warfarin. Infrequently, LA device-related thrombus (DRT) has been suspected. Optimal treatment of DRT is not known, and the efficacy of novel oral anticoagulants (NOAC) in this setting has not been previously described. A 69-year-old woman with permanent atrial fibrillation underwent WATCHMAN device placement. A transesophageal echocardiogram (TEE) performed 45 days following implant revealed a well-seated device. A 1-year follow-up TEE revealed a 1.2 × 0.8 cm sized DRT on the LA aspect of the WATCHMAN device. She was prescribed dabigatran 150 mg po BID for 3 months and she remained on aspirin 325 mg per day. She returned approximately 4 months later (and several weeks after completing her 3-month course of dabigatran) for a repeat TEE, which revealed complete resolution of the DRT. A TEE was performed approximately 8 months later and revealed a new DRT measuring 1 cm in diameter on the LA aspect of the device. This is the first report of successful WATCHMAN DRT treatment with a NOAC, and the first report of late DRT recurrence following treatment to resolution with an anticoagulant. This case report demonstrates that (1) WATCHMAN DRT may form late following implantation, (2) DRT resolution is possible with NOACs, specifically dabigatran, and (3) late recurrence of DRT is possible, even after treatment to initial resolution with systemic anticoagulation.

Contrast enhanced transesophageal echocardiographic guidance of left atrial appendage closure device implantation.

The percutaneous implantation of a left atrial appendage closure device offers an alternative to chronic oral anticoagulation in patients with nonvalvular atrial fibrillation and concomitant risk factors for stroke. Transesophageal echocardiography plays a key role in defining left atrial appendage anatomy and in guiding device implantation. The authors describe a case in which contrast-enhanced transesophageal echocardiography was critically important in spatially resolving the borders of the left atrial appendage, which ultimately led to successful device implantation with cessation of warfarin therapy.