Left Atrial Appendage Closure: Feasible but Still Risky / Will it Though Obviate the Need for Anticoagulation?

Abstract

Various studies and meta-analyses have suggested that in cases of left atrial thrombi in nonrheumatic atrial fibrillation (AF) patients, approximately 90% of them are located in the left atrial appendage (LAA). Patients are effectively protected from thromboembolism in this setting by anticoagulation therapy, shown to reduce the incidence by 60-70% with vitamin K antagonists and maybe more by the newer anticoagulants. However, anticoagulation therapy is limited by an increased risk of major bleeding, in addition to other hindrances, such as difficulty in monitoring anticoagulation therapy, several drug and food interactions for classical warfarin, or cost and bleeding issues with the newer drugs, all leading to limited use of anticoagulation in clinical practice with percentages reported at 30-50%. For these reasons, alternative device therapies with occlusion of the LAA, considered the most common source of thromboembolism in this cohort, have been recently pursued.

In the European PLAATO (Percutaneous Left Atrial Appendage Transcatheter Occlusion) study, the first device ever used for this purpose, which, however, was subsequently withdrawn, had an initial implant success rate of 90% among 180 patients. However, there was a 1.1% mortality (2 patients) related to the procedure, while 6 cases of cardiac tamponade also occurred (3.3%). In two cases, surgical drainage of the tamponade was necessary (1.1%). In one patient the device embolized into the aorta after its release (0.6%) (at the end successfully snared and replaced). During follow-up, 3 strokes occurred (2.3% per year). The expected incidence of stroke according to the CHADS2-Score was 6.6% per year. The trial was halted prematurely during the follow-up phase, allegedly for financial considerations... (excerpt)