Watchman: Alternative to long-term warfarin therapy

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An article published in The Lancet reports that patients with atrial fibrillation at risk of stroke could be offered percutaneous closure of the left atrial appendage instead of long-term warfarin therapy. The findings are from the PROTECT AF study, led by David R Holmes, Mayo Clinic, Rochester, US.

About 90% of atrial thrombi in patients with non-valvular atrial fibrillation are assumed to initiate in the left atrial appendage. The authors examined in this randomised study the efficiency and safety of percutaneous closure of the left atrial appendage compared with long-term warfarin therapy in patients with non-valvular atrial fibrillation at risk for stroke.


Patients eligible for the study had a least one of following: previous stroke or transient ischaemic attack, congestive heart failure, diabetes, high blood pressure, or were 75 years or older. Overall, 707 patients were included in the assessment and 463 were randomised in a 2:1 ratio to percutaneous closure of the left atrial appendage and subsequent discontinuation of warfarin and 244 patients followed long-term warfarin therapy. The percutaneous method involved implantation of a device (the Watchman) to close off the left atrial appendage. Effectiveness was determined through a combined endpoint of all stroke (ischaemic and haemorrhagic), cardiovascular death, and systemic embolism. There were serious adverse events that were measured in the safety assessment. They included major bleeding, pericardial effusion and device embolisation.


Results indicated that after 1,050 patient years of monitoring, there were 3.0 efficacy events per 100 patient-years in the device group. In the warfarin group there were 4.9. This translates to a relative reduction of 38%. On the other hand, serious safety events were more frequent in the device group (7.4 events per 100 patient-years) compared with the warfarin group (4.4 events per 100 patient-years). The majority of these safety events were linked to the procedural implant.


The authors wrote in conclusion: “The efficacy of percutaneous closure of the left atrial appendage 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 left atrial appendage might provide an alternative strategy to chronic warfarin therapy for stroke prophylaxis in patients with non-valvular atrial fibrillation.”


In an associated note, Dominick J H McCabe, Justin A Kinsella, and W Oliver Tobin, Adelaide and Meath Hospital, Dublin, incorporating the National Children’s Hospital, Trinity College, Dublin, Ireland, remark that warfarin has its limitations. However, it is still the preferred treatment for patients with non-valvular atrial fibrillation and who are suitable for long-term oral anticoagulation. But they mention that additional research on the use of left atrial appendage occlusion devices is necessary. This particularly applies for patients unsuitable for long-term warfarin therapy.


The study was funded by Atritech.

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