Background: Percutaneous approaches to left atrial appendage (LAA) closure are being developed for stroke prophylaxis in atrial fibrillation patients as an alternative to warfarin. Non-randomized clinical trials suggested that the first of these devices, the percutaneous left atrial appendage transcatheter occlusion (PLAATO) device, is safe and reduces stroke risk. Percutaneous closure has the potential limitation of incomplete exclusion of LAA from the systemic circulation, which could potentially lead to thrombus formation and stroke. This study investigated the interaction between residual blood flow in the LAA after percutaneous closure with PLAATO and risk of stroke.
Methods and results: Data from the PLAATO trial current as of July 2010 was used for this analysis (n = 22). Mechanical occlusion using the PLAATO device was used in 22 patients (age 68 ± 5, CHADS(2) score = 3.03 ± 0.6). Warfarin and clopidogrel were stopped during follow-up in all but one patient due to development of pulmonary emboli. After an average follow-up of 58 ± 9 months, four out of 22 patients (16.7%) developed a new ischemic stroke/TIA, translating to an annualized embolic rate of 3.63%. There were no differences in the demographics (age, sex, and CHADS(2) score) among patients with and without stroke. Cardiac CT documented peri-device leak in three out of four patients with stroke and in seven out of nine (75% vs. 77%, p = 0.706) patients without stroke that agreed to have a follow-up cardiac CT (Chi squared with Yates correction for this interaction = 0.012, p = 0.912). TEE corroborated these results but failed to identify peri-device leak in three patients without stroke.
Conclusions: The main finding of our analysis suggests that in long-term follow-up, residual flow after LAA occlusion with the PLAATO device, as documented by cardiac CT, is ubiquitous but is not associated with an increased risk of stroke.