MedWire News: A novel implantable device might be a worthy alternative to blood thinners in patients with nonvalvular atrial fibrillation (AF), according to the results of the prospective, randomized PROTECT AF trial.

The PROTECT AF (WATCHMAN left atrial appendage system for embolic PROTECTion in patients with AF) study found that patients allocated to the WATCHMAN device were less likely to suffer hemorrhagic stroke than those given warfarin. Furthermore, the device was as good as warfarin at protecting against ischemic stroke and cardiovascular events.

WATCHMAN is a fabric-covered expandable nitinol cage that, when implanted, blocks the formation of clots in the left atrial appendage, a common site of clot formation in AF patients.

“The placement of the WATCHMAN device achieves excellent outcomes, eliminating hemorrhagic strokes and major bleeding often associated with the use of warfarin,” said David Holmes, Jr (Mayo Graduate School of Medicine, Rochester, Minnesota, USA). Holmes reported the PROTECT AF results at the 58th Annual Scientific Session of the American College of Cardiology, in Orlando, Florida.

The PROTECT AF trial assigned 707 patients with nonvalvular AF to receive WATCHMAN (n=463 patients) or long-term warfarin treatment. Patients in the device arm were slated to receive warfarin for 45 days. Enrollment for the trial is ongoing in a Continuous Access Registry.

At 45 days, 87.0% of patients in the device arm were able to stop warfarin. By 6 months, 92.5% of device patients were off warfarin, and the rate continued to increase over time.

The device was successfully implanted in 90.9% (408/449) of attempts. After 900 patient-years of follow-up, the combined rate of stroke (ischemic and hemorrhagic) and cardiovascular death was 3.4% in the device group versus 5.0% in the warfarin group. This amounted to a 32% reduction in event rate overall with the device, showing that that the device was non-inferior to warfarin.

More procedural-related complications were observed in the device than warfarin arm: 8.7 versus 4.2 per 100 patient-years. Pericardial effusion occurred in 6.5% of patients early in the trial, but the rate was reduced to 4.4% after the implementation of device modifications and training enhancement. Holmes noted that the rate of pericardial effusion is now down to 1.1% in the Continued Access Registry.

Five ischemic strokes occurred in the device group, all of them periprocedural. One hemorrhagic stroke occurred in the device group versus six in the control group (0.2% versus 1.9%, respectively). The hemorrhagic stroke in the device group occurred 15 days post implant. This happened while the patient was still on warfarin, which Holmes called “double jeopardy.”

The number of deaths was 17 in the device group (two from stroke, three from unknown/other cardiovascular causes and 12 from noncardiovascular causes) and 15 in the warfarin group (four from stroke, six from unknown/other cardiovascular causes, and five from noncardiovascular). No deaths in the device group were procedure- or device-related, Holmes said.

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