Left Atrial Appendage Occlusion for Stroke Prevention in Patients with Nonrheumatic Atrial Fibrillation

Introduction: Atrial fibrillation is a common rhythm disorder, which is related to a higher risk of thrombembolism resulting in a high rate of cerebral stroke or transient ischemic attacks. According to the CHADS₂- or CHA₂DS₂Vasc-Score there is an indication for oral anticoagulation to prevent patients from mostly disabling strokes. However, more than 50% of patients are not adequately treated with oral anticoagulation due to different reasons, especially contraindications. More than 90% of thrombi develop in the left atrial appendage (LAA), which lead to the idea of developing devices to exclude the LAA from the systemic circulation to prevent patients from embolisations. Another approach is surgical ligation or removal of the LAA during operation procedures. Content: Different devices and their clinical data are discussed in this review. Available literature for most of the devices is evaluated and last but not least some surgical results are discussed at the end. Existing data of randomized and non-randomized studies show that the concept of LAA-occlusion instead of anticoagulation therapy works. However, complication rates during intervention have to be kept in mind, but with adequate training also new and inexperienced operators can do the procedure safely. Most data and the only randomized studies are available for the Watchman Device. Despite some few complications like pericardial effusions, bleeding complications and thrombus formation on the devices, the data showed a non inferiority of device-implantation in comparison with anticoagulation therapy in the first few years. In long term follow up more than 4 years after implantation, there is even a superiority of the device compared with anticoagulation therapy, safety issues are no longer significantly different despite some periprocedural complications. This has to be reflected with the background, that operators could treat 3 patients with a totally new method, thereafter all patients had to be randomized into the study. So experience was limited in the first phase of this trial. Surgical data vary much due to different techniques of LAA-occlusion. With newer devices results are also promising. Conclusion: LAA-occlusion is a developing field of interventional and surgical techniques. The concept of LAA-occlusion could be proved in one randomized trial. At least for patients contraindicated for anticoagulation therapy, LAA-occlusion is a real alternative to only aspirin therapy or doing nothing. With emerging techniques and lower complication rates, LAA-occlusion might develop to a real alternative to anticoagulation therapy, at least for vitamin-K-antagonists. There are no data available so far in comparison with new oral anticoagulants. Further studies are needed to compare device therapy with new oral anticoagulants.