Ahmad Masri Profile picture
Sep 27, 2018 18 tweets 10 min read Twitter logo Read on Twitter
1/ A long thread on LifeVest. I promise it will be entertaining. If you find any inaccuracies please let me know.

Paper of VEST published here - will discuss background to WCD and #VEST but not the trial itself nejm.org/doi/full/10.10…
2/ In 2001, FDA gave approval to Lifecor for the first WCD. Later Lifecor was acquired by Zoll (2004 agreement, 2006 acquisition). Zoll maintains a registry for prescribed LifeVests. But lets go back to the FDA approval process.
3/ Lifecor presented 2 separate prospective studies to the FDA; WEARIT and BIROAD. FDA asked for both to be combined into 1 study, and each study representing a subgroup. A total of 289 patients were included.
4/ WEARIT (177 pts, NYHA ≥ III, LVEF< 30%). BIROAD (112 pts, MI c/b VT, EF < 30% 3 days after MI, syncope, SCD 48 hours after MI but not candidate for ICD or refused it, or VT post CABG).
5/ follow up: 901 patient-months, 6 out of 8 VT/VF treated by WCD. This was COMPARED to HISTORICAL controls who suffered SCD at home and called emergency services, in whom successful SCD resuscitation was 25%.
6/ Also, only 27% of patients in WEARIT were taking a beta-adrenergic antagonist, 34% were on anti-arrhythmic medications, and 45% were on inotropes.
7/FDA concluded - WCD device had greater efficacy than bystander resuscitation in the historical control group - thus was approved
8/So WCD was approved and ready for commercialization and many iterations over the years. Zoll kept a database which was used for publication purposes. Since then, many studies have been published. Few independent reports as most used the Zoll database.
9/ By our team's count, only 6 studies totaling 710 patients, of which 74% were from a single center study, were independent studies (no Zoll COI, Zoll funding, or commercial database use) out of around 28 studies with 33K patients.
10/ In 2016, AHA expert consensus gave IIB rec for WCD. In 2017, ACC/AHA/HRS gave IIa rec for WCD in secondary prevention when ICD removal is required and IIb rec for all other scenarios, including primary prevention.
11/ Why no RCTs? In 2007, NIH funding for VEST (NCT01446965, 5U01HL089458) started – continued until 2011 for data coordination. Zoll sponsored the other 80% initially, then sponsored the whole trial.
12/Slow enrollment led to changing end-point from all-cause mortality at 60 days (n=4506) to SCD or non-sudden death due to VT This happened after enrolling 244 patients (year 2010).
13/ target n changed to 1900. On Clinicaltrials.gov, target n then changed again on 6/15/16 to 2300 (in NEJM paper – “In October 2015, on the basis of lower-than-expected device wear time and without the inspection of outcome differences according to trial group”
14/ You might wonder then why did we practice for that long without evidence? IRIS & DINAMIT both showed no overall mortality benefit to early ICD implantation despite reduced arrhythmic mortality because reduction in SCD was offset by competing non-arrhythmogenic causes of death
15/ To Zoll this was all going well. This is taken from a Zoll business presentation available here (asahi-kasei.co.jp/asahi/jp/ir/li… )
Note that the report states up to 2015, 200,000 patients have been protected
thoughts? can go here for some statistical take on this

• • •

Missing some Tweet in this thread? You can try to force a refresh

Keep Current with Ahmad Masri

Ahmad Masri Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!


Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!


0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy


3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us on Twitter!