LifeVest study results: PR spin machine in full effect at American College of Cardiology meeting

Joy Victory is deputy managing editor of She tweets at @thejoyvictory.

In a remarkable example of PR spin, both the American College of Cardiology and Zoll, a medical devicemaker, issued misleading news releases this weekend trumpeting the results of a study examining the LifeVest, a wearable cardiac defibrillator.

The LifeVest, which has been in use for nearly two decades, is sometimes prescribed to recent heart attack patients who have “low ejection fraction,” or a reduced ability to pump blood. These patients are thought to be at high risk of sudden cardiac arrest, and the LifeVest is designed to deliver powerful shocks that resuscitate a person when it detects a deadly heart rhythm.

However, critics have warned that the device’s purported benefits may not outweigh the harms, which we chronicled in detail last month: “Wearable defibrillator is said to save lives, but patients and doctors question at what cost.”

For years, a lack of rigorous LifeVest study results made it hard to know what the right thing was to do for patients. It’s a problem common to many medical devices: Compared to drugs, the FDA requires less evidence that devices are safe to use and work as intended, and many unsafe devices remain on the market, even when known safety problems exist.

That’s why we and many others were curious to see the results of a randomized controlled trial, known as VEST, that was presented this weekend at the American College of Cardiology’s 67th Annual Scientific Session. Would the LifeVest study results provide proof that the vest was worth the hassle? How would it be summarized and pitched to the news media?

PR machines turn on the spin cycle

The findings: The study results for the primary endpoint were negative, meaning there wasn’t sufficient evidence to show the device reduced sudden cardiac arrest in post-heart attack patients. In the group that wore the vest, 1.6% died from sudden cardiac arrest, and in the group that didn’t wear the vest, 2.4% died. That was not a statistically significant difference.

Yet two news releases issued by the devicemaker, Zoll, and the ACC, glossed over this finding, and focused on a secondary endpoint of the trial, which was the rate of overall mortality in the two groups. By playing up this finding, they made it seem like the vest was proven to work–and worth the cost and risks of wearing the device.

Not only do they hype a secondary finding, they do so by using relative risk percentages to fluff up the benefit and make it look more impactful than it really was (which, as we explain here, is a common tactic used by researchers or PR teams trying to make results look better than they really are).

In this case, the news releases say the vest reduces total mortality by 36%. That sounds like a big difference. However, in absolute terms, 3.1% of the vest group died from any cause in the three-month period, and 4.9% died in the non-vest group, a difference of 1.8% percentage points.

Based on the reporting from this Medscape news coverage of the meeting, researchers involved with the study speculated that it might be because some of the deaths in the vest group were attributed to other causes, when they actually died from sudden cardiac arrest.

“This would reduce power for sudden death, but not for total mortality,” Jeff Olgin, MD, from the University of California, San Francisco said during his formal presentation of the trial, according to Medscape.

Several cardiologists quoted in the coverage voiced skepticism around this theory, noting that until further research is conducted, we simply have no idea why there was a slightly higher overall death rate in the control group than the vest group. It could be due to chance, especially since the event rates were low overall, and because the difference in death rates was just barely statistically significant.

Harms are downplayed

zoll lifevest wearable defibrillatorAs we’ve written about, there are extensive reports that the device causes problems for wearers–including serious skin rashes and inappropriate shocks. The same problems were seen in the trial.

But the risks of wearing the device–which include death–were not mentioned in either news release. Despite the negative results–and the known risks–the ACC news release even included this quote:

“What’s nice about the wearable defibrillator is that it’s non-invasive and it’s not permanent,” Olgin said. “Based on our results, I think we’ll see more widespread use of this device in these patients.”

‘Expensive and burdensome’

This spin was alarming to John Mandrola, MD, a Kentucky cardiac electrophysiologist who has long been openly critical of the vest, also referred to as a WCD, or wearable cardiac defibrillator.

As he states in his column, “If this negative trial leads to more use of the WCD, I am afraid hype, marketing, and fear will have won out over critical appraisal. And that would be a sad day for medical science.”

He later shared a photo of an advertisement for the LifeVest that’s displayed over the escalators at the ACC meeting:

“This is ugly,” he tweeted. “Cardiologists ought to be offended and then stand against this nonsense. Shame on Zoll for not advertising the primary endpoint.”

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Bruce Hadley

March 16, 2018 at 6:57 pm

Why is it that your article never mentioned the fact when this trial started with the original primary endpoint of “total mortality” and that is was changed to “reduction in sudden cardiac death because they couldn’t enroll 4,500 patients?