Primary Results From the Understanding Outcomes With the S-ICD in Primary Prevention Patients With Low Ejection Fraction (UNTOUCHED) Trial

Media type: E-Article
Title: Primary Results From the Understanding Outcomes With the S-ICD in Primary Prevention Patients With Low Ejection Fraction (UNTOUCHED) Trial
Contributor: Gold, Michael R.; Lambiase, Pier D.; El-Chami, Mikhael F.; Knops, Reinoud E.; Aasbo, Johan D.; Bongiorni, Maria Grazia; Russo, Andrea M.; Deharo, Jean-Claude; Burke, Martin C.; Dinerman, Jay; Barr, Craig S.; Shaik, Naushad; Carter, Nathan; Stoltz, Thomas; Stein, Kenneth M.; Brisben, Amy J.; Boersma, Lucas V.A.; Phelan, Timothy; Al-Ameri, Hazim; Albirini, Abdulhay; Alimohammad, Rizwan; Arias, Miguel; Badenco, Nicolas; Bertaux, Geraldine; [...]
imprint: Ovid Technologies (Wolters Kluwer Health), 2021
Published in: Circulation
Language: English
DOI: 10.1161/circulationaha.120.048728
ISSN: 0009-7322; 1524-4539
Origination:
Footnote:
Description: <jats:sec> <jats:title>Background:</jats:title> <jats:p>The subcutaneous (S) implantable cardioverter-defibrillator (ICD) is safe and effective for sudden cardiac death prevention. However, patients in previous S-ICD studies had fewer comorbidities, had less left ventricular dysfunction, and received more inappropriate shocks (IAS) than in typical transvenous ICD trials. The UNTOUCHED trial (Understanding Outcomes With the S-ICD in Primary Prevention Patients With Low Ejection Fraction) was designed to evaluate the IAS rate in a more typical, contemporary ICD patient population implanted with the S-ICD using standardized programming and enhanced discrimination algorithms.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods:</jats:title> <jats:p>Primary prevention patients with left ventricular ejection fraction ≤35% and no pacing indications were included. Generation 2 or 3 S-ICD devices were implanted and programmed with rate-based therapy delivery for rates ≥250 beats per minute and morphology discrimination for rates ≥200 and <250 beats per minute. Patients were followed for 18 months. The primary end point was the IAS-free rate compared with a 91.6% performance goal, derived from the results for the ICD-only patients in the MADIT-RIT study (Multicenter Automatic Defibrillator Implantation Trial–Reduce Inappropriate Therapy). Kaplan-Meier analyses were performed to evaluate event-free rates for IAS, all-cause shock, and complications. Multivariable proportional hazard analysis was performed to determine predictors of end points.</jats:p> </jats:sec> <jats:sec> <jats:title>Results:</jats:title> <jats:p>S-ICD implant was attempted in 1116 patients, and 1111 patients were included in postimplant follow-up analysis. The cohort had a mean age of 55.8±12.4 years, 25.6% were women, 23.4% were Black, 53.5% had ischemic heart disease, 87.7% had symptomatic heart failure, and the mean left ventricular ejection fraction was 26.4±5.8%. Eighteen-month freedom from IAS was 95.9% (lower confidence limit, 94.8%). Predictors of reduced incidence of IAS were implanting the most recent generation of device, using the 3-incision technique, no history of atrial fibrillation, and ischemic cause. The 18-month all-cause shock-free rate was 90.6% (lower confidence limit, 89.0%), meeting the prespecified performance goal of 85.8%. Conversion success rate for appropriate, discrete episodes was 98.4%. Complication-free rate at 18 months was 92.7%.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions:</jats:title> <jats:p>This study demonstrates high efficacy and safety with contemporary S-ICD devices and programming despite the relatively high incidence of comorbidities in comparison with earlier S-ICD trials. The inappropriate shock rate (3.1% at 1 year) is the lowest reported for the S-ICD and lower than many transvenous ICD studies using contemporary programming to reduce IAS.</jats:p> </jats:sec> <jats:sec> <jats:title>Registration:</jats:title> <jats:p> URL: <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://www.clinicaltrials.gov">https://www.clinicaltrials.gov</jats:ext-link> ; Unique identifier: NCT02433379. </jats:p> </jats:sec>
Access State: Open Access

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