Patients with atrial fibrillation at risk of stroke could be offered percutaneous closure of the left atrial appendage instead of long-term warfarin therapy, according to findings from the PROTECT AF study reported in the Aug. 13 edition of the Lancet.
More than 90 percent of atrial thrombi in patients with non-valvular atrial fibrillation are believed to originate in the left atrial appendage (LAA). In this randomized study, David R. Holmes, MD, from the Mayo Clinic in Rochester, Minn., and colleagues assessed the efficacy and safety of percutaneous closure of the LAA compared with long-term warfarin therapy in patients with non-valvular atrial fibrillation at risk for stroke.
According to the authors, patients were eligible for the study if they had at least one of the following: previous stroke or transient ischemic attack, congestive heart failure, diabetes, high blood pressure or were 75 years or older. Investigators randomized 707 patients in a 2:1 ratio to percutaneous closure of the LAA and subsequent discontinuation of warfarin (463 patients) or to long-term warfarin therapy (244 patients).
The percutaneous procedure involved implantation of a device (Watchman from Plymouth, Minn.-based Atritech) to close off the LAA. The researchers assessed efficacy through a combined endpoint of all stroke (ischemic and hemorrhagic), cardiovascular death and systemic embolism. However, other serious adverse events included in the safety assessment were major bleeding, pericardial effusion and device embolization.
After 1,065 patient years of follow up, Holmes and colleagues found that there were 3 efficacy events per 100 patient-years in the device group, compared with 4.9 in the warfarin group—a relative reduction of 38 percent. However, serious safety events were more common in the device group (7.4 events per 100 patient-years), compared with the warfarin group (4.4); most of these safety events were related to the procedural implant.
Based on their findings, the authors concluded that the “efficacy of percutaneous closure of the LAA with this device was non-inferior to that of warfarin therapy. Although there was a higher rate of adverse safety events in the intervention group than the control group, events in the intervention group were mainly a result of periprocedural complications. Closure of the LAA might provide an alternative strategy to chronic warfarin therapy for stroke prophylaxis in patients with non-valvular atrial fibrillation."
In an accompanying commentary, Dominick J. H. McCabe, MD, Justin A. Kinsella, MD, and W. Oliver Tobin, MD, from Adelaide and Meath Hospital, the National Children's Hospital and Trinity College—all located in Dublin, Ireland—wrote that despite its limitations, warfarin is still the treatment of choice for patients with non-valvular atrial fibrillation who have clear indications for, and who are suitable for long-term oral anticoagulation.
However, they added that further research is warranted into the use of LAA occlusion devices, particularly for patients unsuitable for long-term warfarin therapy.