ORLANDO, FL — Patients who started wearing the LifeVest (ZOLL Medical) within 7 days of an acute myocardial infarction that left them with a low ejection fraction did not show a significant reduction in the primary end point of sudden death during the next 3 months in a randomized trial.
The risk for death from any cause, a secondary end point, did fall significantly for patients using the device, an external defibrillator worn in a harness under clothing, in the 2302-patient Vest Prevention of Early Sudden Death (VEST) trial.
It’s “reasonable” to prescribe the LifeVest early after an acute MI for patients with a left ventricular ejection fraction of 35% or less as a protective bridge until they become eligible for consideration of an implantable cardioverter defibrillator, concluded Jeffrey E Olgin, MD, from the University of California, San Francisco, presenting the study here at the American College of Cardiology (ACC) 2018 Annual Scientific Session.
Some will see the trial as outright negative, while others will see it in more positive terms, Dhanunjaya R Lakkireddy, MD, from the University of Kansas, Kansas City, who isn’t connected with VEST, told theheart.org | Medscape Cardiology.
“It’s not a resounding success. I think it’s still positive for total mortality, but it didn’t meet its primary end point,” he said. The device has been and will continue to be used in clinical practice, but it’s possible that “enthusiasm” for the device “would be tempered to some degree,” now that the VEST trial results are known.
Lakkireddy said his group uses LifeVest now in early post-MI patients, but in a narrower, higher-risk group than that entered in VEST. “Not everybody that has an ejection fraction of less than 35% should walk out of the hospital after an MI with the vest.”
High-risk early post-MI patients for whom he’d still recommend its use after the trial include low–left ventricular ejection fraction patients with other high-risk features such as frequent premature ventricular contractions or nonsustained ventricular tachycardia. That is, he said, “those in whom the risk of ventricular tachyarrhythmia events is very high.”
Others saw the trial as resoundingly negative.
Aside from the major point that the trial was negative for the sudden death primary outcome, only 20 patients wearing the LifeVest received appropriate shocks, pointed out Suneet Mittal, MD, from the Valley Health System, Ridgewood, New Jersey, who also was not connected with VEST.
Therefore, Mittal told theheart.org | Medscape Cardiology, a large number of people used the wearable cardioverter defibrillator and didn’t derive any benefit from it, but did experience inappropriate shocks and a lot of discomfort. He pointed to the high prevalence of torso itching and rashes in the LifeVest group compared with those assigned to the control group.
And the number needed to treat is high, “Even if we believe the total mortality data,” Mittal said. “This is important, given the costs inherent to the wearable cardioverter defibrillator.”
Guidelines have long recommended against using implantable cardioverter defibrillators for primary prevention of sudden death for at least 40 days after an MI, or at least 90 days if the MI was treated with percutaneous coronary intervention.
The proscriptions stem primarily from two trials, DINAMIT from 2004 and IRIS from 2009, that found no survival benefit and possibly an increase in all-cause mortality when implantable defibrillators were used in the early post-MI period.
VEST follows observational experience suggesting that the LifeVest successfully delivered appropriate shocks to 1.4% of more than 8000 patients who wore the device during the early post-MI period in which implantable cardioverter defibrillators are avoided.
Patients enrolled in VEST at more than 100 sites in the United States and Europe were randomly assigned 2:1 to use or not use the LifeVest (1524 and 778 patients, respectively) on top of guideline-based medical therapy starting within a week of an acute MI.
The patients who were given the device were asked to wear it as much as possible, removing it only for bathing, the researchers said. Ultimately, they wore it an average of 14.1 hours per day.
During a mean follow-up of 84.3 days, sudden death occurred in 1.6% of patients assigned to the device and 2.4% of those receiving standard meds only (P = .18) by intention-to-treat.
Mortality was 3.2% in the LifeVest group and 4.9% of the control group, for a relative mortality risk reduction of 35.5% (P = .04).
There were no fatal strokes in the device group, but four in the control group (0.5%; P = .01).
Table 1. Primary and Secondary 90-Day Outcomes in VEST
| End Points | LifeVest (n = 1524), % | Control (n = 778), % | P |
| Sudden death (primary endpoint) | 1.6 | 2.4 | .18 |
| Any nonsudden death | 1.4 | 2.2 | .15 |
| Death from congestive heart failure | 0.7 | 0.6 | 1.0 |
| Fatal recurrent MI | 0.1 | 0.1 | 1.0 |
| Stroke death | 0.0 | 0.5 | .01 |
| Death, any cause | 3.1 | 4.9 | .04 |
| Cardiovascular rehospitalization | 22 | 22 | .81 |
In the LifeVest group, 13 patients had one appropriate shock during the follow-up, and seven had at least two (1.4% had at least one shock). Eight and two patients, respectively, had one and more than one inappropriate shocks (so 0.6% had at least one inappropriate shock).
There were no significant differences between the groups in symptoms such as fatigue, trouble sleeping, dizziness or fainting, nausea or headache, or chest pain. But patients assigned to the device experienced a significant excess of some symptoms, several of which were related to the LifeVest as a wearable device.
Table 2. Prevalence of Notable Adverse Effects by 90 Days in VEST
| End Points | LifeVest, % | Control, % | P |
| Shortness of breath | 38.7 | 45.4 | .003 |
| Chest pain | 18.7 | 21.4 | .14 |
| Rash, any location | 15.2 | 7.1 | <.001 |
| Rash on torso | 12.9 | 3.8 | <.001 |
| Itch, any location | 17.2 | 6.4 | <.001 |
| Itch on torso | 14.5 | 3.1 | <.001 |
Lakkireddy said he’s looking forward to a subgroup analysis from the trial. “Once it comes out, it will really throw more light on this subject. Perhaps we can come up with high-risk markers [for patients] that will still benefit from having the vest in place.”
This story will soon be updated with more extensive results and commentary.
VEST was funded in part by the National Institutes of Health and Zoll Medical. Olgin discloses receiving consulting fees or honoraria from VivaLink. Mittal and Lakkireddy have disclosed no relevant financial relationships.
American College of Cardiology (ACC) 2018 Annual Scientific Session: Abstract 401-10. Presented March 10, 2018.
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