ACC: Tomaselli parses out Watchman's role in practice, PREVAIL drama

SAN FRANCISCO—Former American Heart Association (AHA) President Gorden F. Tomaselli, MD, sat down with the media to discuss the confounding results from the PREVAIL trial, and how the Watchman device could be applicable in clinical practice, if FDA approved.

The PREVAIL trial, the results of which evaluated the Watchman device (Boston Scientific) to standard therapy of warfain, was set to be released as a late-breaking clinical trial, but it was pulled due to an embargo break by the trial’s sponsor, Boston Scientific. Tomaselli, an electrophysiologist and director of cardiology at Johns Hopkins University School of Medicine in Baltimore, helped to parse some of the data out at the American College of Cardiology (ACC) scientific session on March 9.

Would you refer your patients to the Watchman device, if approved by the FDA?

I would not recommend Watchman for patients who present with new onset atrial fibrillation. In those cases, it’s not going to be an option of oral anticoagulants or Watchman [Boston Scientific]. However, I would refer patients under certain circumstances, particularly those who cannot take oral anticoagulants due to problems with certain bleeding complications and those that have a high CHAD2 score. This patient population equates to approximately 5-10 percent of those I see in practice.

If I were able to look in a crystal ball, I would speculate that they will approve Watchman in a restricted set of circumstances. Right now, we don’t have the data to suggest its use in lieu of oral anticoagulants had they not had a problem with oral anticoagulants or demonstrated to have thromboembolic events on oral anticoagulants or another direct factor IIa inhibitors. Therefore, I think it could get approved under a restricted label, especially in those patients in whom we have very few other options.

How does PREVAIL impact to your understanding of the device’s safety and efficacy?

I have no idea how to explain the drama surrounding the release of the trial’s findings. Certainly, it’s something that we all need to keep in the back of our minds. And each of the slides from PREVAIL state that these data are preliminary, suggesting that these aren’t the final data. There are statistical gymnastics with these PREVAIL data, everything from a one-sided confidence interval for the seven-day outcomes to the three levels of primary endpoints. This trial was as much about deployment of this device as it was the efficacy of the device.

I am convinced that the device is reasonably safe. Am I convinced it’s completely safe? Absolutely not.

It’s not necessarily only this trial that allows me to draw conclusions on the safety of the device. It’s this trial and PROTECT AF, along with the registry data that is compiled between them. In addition, after PROTECT AF, the researchers were allowed to continue to enroll patients in the continued access trial (CAP) to assess the device deployment and complications.

Therefore, the drama surrounding the release of the trial does not impact my understanding of the device, but I anxiously await the final results presented. There was a substantial complication rate in PROTECT AF around deployment. After seeing these data concerning the seven-day safety outcomes, now I’m a little more comfortable that it can be deployed safely by competitive catheterizers—both interventional cardiologists and electrophysiologists.