Minimally invasive left atrial appendage ligation in an animal model

Evaluation of: Lee RJ, Bartus K, Yakubov SJ: Catheter-based left atrial appendage (LAA) ligation for the prevention of embolic events arising from the LAA: initial experience in a canine model.Circ. Cardiovasc. Interv. 3(3), 224-229 (2010). Stroke is the most common reason for permanent disability in the developing world. Nearly 15% of all strokes can be attributed to atrial fibrillation. The overwhelming majority of thrombi related to atrial fibrillation occur in the left atrial appendage. Although conventional preventive treatment with anticoagulation substantially reduces stroke risk in patients with atrial fibrillation, owing to the associated bleeding risk and frequent failure to maintain a therapeutic range, many patients are either untreated or treated suboptimally. Therefore, alternative treatment strategies have been explored recently. Pharmacologic alternatives include direct thrombin inhibitors, novel vitamin K antagonists and Factor Xa antagonists. Although some agents, particularly thrombin antagonists, such as dabigatran, are promising, by virtue of the treatment mechanism (anticoagulation), a bleeding risk remains, as well as the potential for drug-drug interaction and other adverse effects. These limitations have fostered interest in mechanical isolation of the left atrial appendage, either surgically (e.g., with concomitant heart surgery) or percutaneously. The results of routine surgical left atrial appendage closure have been mixed. However, recently, percutaneous closure has been compared with conventional anticoagulation, demonstrating noninferiority with device therapy. Optimally, one would like to achieve reliable and complete closure without the use of a permanently implanted foreign object, which may be associated with thrombus formation. To this effect, Lee et al. have explored the feasibility of minimally invasive left atrial appendage ligation in an animal study. This technique avoids the implantation of a permanent foreign object. The study design and results will be summarized and discussed below.