Transcatheter occlusion of the left atrial appendage

Cardiology Review® Online, June 2006, Volume 23, Issue 6

Atrial fibrillation commonly affects millions of patients, and often causes the disabling complication of cardioembolic stroke.

Atrial fibrillation commonly affects millions of patients, and often causes the disabling complication of cardioembolic stroke.1 Anticoagulation with warfarin can effectively reduce the annual incidence of stroke caused by atrial fibrillation, as well as other embolic complications, but is associated with management problems as well as potentially serious bleeding complications. Finding a new alternative to long-term anticoagulation with warfarin, therefore, is desirable.2

The left atrial appendage (LAA) has been documented as the source of thrombus formation and thus embolic events in patients with nonrheumatic atrial fibrillation. Occlusion of the LAA has become a relatively common surgical procedure, and that, combined with coronary artery bypass to prevent strokes postoperatively, has become part of American College of Cardiology/American Heart Association guidelines.3 In this issue, Sievert et al present a study evaluating the safety and feasibility of a new percutaneous device for closing the LAA that has undergone clinical trials.

The PLAATO system is a self-expanding nitinol cage covered by polytetrafluoroethylene. It is delivered into the LAA under fluoroscopy and transesophageal echocardiography (TEE) guidance via a transeptal technique (12F transeptal hole), and can be done under conscious sedation. The authors studied 111 patients, aged 71 ± 9 years, all of whom had nonrheumatic atrial fibrillation for at least 3 months and a risk profile that made them more prone for embolic stroke. The device was successfully implanted in 108 patients. Complications of a serious nature occurred in 9 patients, of whom 3 did not receive the device. At 6 months 98% of the implanted patients with assessable TEE showed successful LAA occlusion.

One patient developed a laminar thrombus on the device, which resolved with aspirin and clopidogrel therapy after 6 months. There was no evidence of mitral valve or pulmonary vein inflow impairment in any of the patients on follow up, nor were any devices dislodged. During a follow-up period of 91 patient-years there were 6 deaths, none of which were procedure or device related. There were 2 strokes, producing an annual stroke rate of 2.2%.

Although the device did not eliminate stroke altogether, the study showed a reasonable efficacy and safety rate for this new device with a 65% stroke rate reduction. I believe as subsequent generations of this device evolve and experienced operators improve their techniques, these numbers can only improve and this may become the favored procedure for many more of the millions of atrial fibrillation patients. As recent events in Israel have demonstrated, warfarin therapy is fraught with problems even in the best of hands.