Overall, most panel members felt the sponsor showed the device to be effective, although there were caveats. Many were uncomfortable with the size of the 800-patient study. Others were uncomfortable making a decision about effectiveness with end points such as hemorrhagic stroke, which was included in the primary efficacy end point. They felt a decision on effectiveness was difficult when there were so few hemorrhagic strokes—five in the control arm and one with the Watchman device—while others thought ischemic stroke, which occurred more frequently in the device arm, would have been a more reliable end point.Whether the FDA will approve the lukewarm endorsement remains to be seen, but the first big hurdle for this device has been passed.
Regarding safety, there was also a divergence of opinion. Again, panel members were concerned about assessing the long-term safety of the data given the short-term PROTECT-AF study. Some, including Dr Michael Domanski (National Heart, Lung, and Blood Institute, Bethesda, MD), said it was pretty hard to look at the data and say the device is safe.
"I would think it would be a mistake for the FDA to approve this device," said Domanski.
Still, opinions like this were the minority, and most felt the "devastating" effects of warfarin over time need to be balanced with the increased risks with the device, such as pericardial effusion, device embolization, and thrombus formation on the device. In contrast, warfarin is a lifetime drug that can be difficult to manage, especially in the elderly and frail, many panel members felt.