VEST trial falls short, fails to reduce sudden death rates with wearable defibrillator

The VEST study—an effort to reduce post-myocardial infarction (MI) mortality and one of ACC 18’s most anticipated clinical trials—failed to meet its primary endpoint of reducing sudden death due to ventricular arrhythmias, study leader Jeffrey Olgin, MD, announced to a crowd of thousands following ACC’s opening ceremony Saturday.

VEST was a controlled attempt at using a wearable cardioverter defibrillator to reduce sudden death rates in a high-risk, post-MI population, Olgin said. The vest itself, which was worn by 1,524 study participants with left-ventricular ejection fraction (LVEF), packs a central monitoring system, self-gelling electrodes, dry ECG electrodes and a rechargeable monitor into one close-fitting, washable garment. The idea is that, if a patient starts experiencing dangerous or abnormal heart rhythms, the vest alerts that patient with a shock and a verbal reminder to call 911.

Olgin said the study was prompted by a handful of other trials, including VALIANT, DINAMIT and IRIS, which stipulated that sudden death rates, while high in the post-MI period, aren’t statistically reduced with early administration of an implantable cardioverter defibrillator (ICD). Those results, alongside JACC guidelines that recommend against implanting an ICD prior to 40 days post-MI, led Olgin’s team to the VEST hypothesis.

The researchers ultimately recruited 2,302 patients across centers in the U.S., Germany, Poland and Hungary between 2008 and 2017. Participants, who had to have been discharged from the hospital within a week of an acute MI and have an ejection fraction of 35 percent or less, were randomized two-to-one to either guideline-directed therapy with a wearable cardioverter defibrillator (WCD) or guideline-directed therapy alone.

Olgin and his colleagues conducted follow-up at one and three months, he said, and found that, in all, wearing the defibrillator vest had a minor impact on sudden death mortality. Of the thousands of enrolled patients, 20—less than 1 percent of the population pool—received an appropriate shock, and 10 patients total received inappropriate shocks during the trial. A far greater subset of 69 patients received shocks but aborted them as false alarms, which was possible with a response button fixed on the vest’s battery pack.

Twenty-five patients with WCDs died of sudden cardiac death during the trial, and 19 in the control group died of the same cause. Both cohorts experienced similar symptoms for the duration of the study, barring shortness of breath, which was markedly higher in the control group. Vest-wearers were more likely to experience rashes and itching, but, Olgin said, that was to be expected from a wearable device.

He said another roadblock to the success of the vest could be its bulky nature.

“As with almost all of our therapies, there will be a portion of patients who are non-compliant,” he said. “The patient should be brought into the decision about whether they should have this therapy, whether they should take it home, whether they should wear it. I think there’s room for improvement to make the therapy more tolerable and easier to wear for everybody.”

Dhanunjaya Lakkireddy, MD, ACC’s Kansas governor and a panelist who wasn’t involved in the study, said he’d continue using the technology in high-risk patients in his own practice.

“I think this is a very important study, because it really highlights the concept of risk of death in the post-MI period,” he said. “Can we write off an external defibrillator entirely? I don’t think so.”

Olgin said the research team locked in their data less than three weeks ago and are waiting to further analyze vest compliance and patient quality of life, as well as a host of other group-level evaluations.