Results from a newly-released study heavily support the idea that Implantable cardioverter-defibrillator-use contributes to low mortality rates in patients suffering from heart failure.

The late-breaking-research was presented in a Hot Line Session at the European Society of Cardiology (ESC) Congress 2019, together with the World Congress of Cardiology in Paris and published in Circulation.

This study investigated the association between ICD use and all-cause mortality in a contemporary reduced ejection fraction (HFrEF) cohort with a focus on subgroups. The study population was compiled from patients in the Swedish Heart Failure Registry (SwedeHF) fulfilling ESC criteria for primary prevention ICD use. Propensity score matching was used to account for differences at baseline.

In a release principal investigator Dr. Benedikt Schrage of the Karolinska Institute in Stockholm, Sweden said: “Most randomized trials on ICD use for primary prevention of sudden cardiac death in HFrEF enrolled patients more than 20 years ago. However, characteristics and management of HFrEF have substantially changed since then and it is not known whether ICD improves outcomes on top of contemporary treatments. Furthermore, it is unclear whether ICD use is equally beneficial in subgroups such as both women and men or older and younger patients.”

Results pointed out that of 16,702 eligible patients in SwedeHF registry, 1,599 (9.6%) had an ICD.

“Among patients from SwedeHF fulfilling ESC criteria for primary prevention ICD use, less than 10% had the device,” Dr. Schrage said in the release. “ICD use in Sweden is known to be lower than in other European countries (e.g. Germany or Italy). This could be because most heart failure patients are seen by primary care physicians and geriatricians who could be less inclined to accept device therapy and have a higher perception of contraindications compared to cardiologists.”

The propensity-matched population consisted of 1,296 ICD users and 1,296 patients without an ICD. The researchers found that ICD use was associated with a 26% relative reduction in the risk of all-cause mortality at one year and a 13% relative reduction in the risk of all-cause mortality at five years. The five-year absolute risk reduction with ICD use was 3.1% leading to 33 patients needing to be treated to prevent one death in five years.

The short-term and long-term mortality benefit was consistent across subgroups, such as patients with or without ischemic heart disease, males and females, patients under 75 and 75 and older, those enrolled earlier vs. later in SwedeHF and thus receiving less or more contemporary treatment, and also for patients with or without cardiac resynchronization therapy.

“The study found that primary prevention ICD was associated with reduced short-term and long-term all-cause mortality in HFrEF overall and in several subgroups,” Dr. Schrage said in a release. “Our findings support the current recommendations and call for better implementation of ICD use in clinical practice.”

There have been some significant developments with ICDs in the past months. In May, Boston Scientific unveiled highly-favorable results from a study evaluating the safety and efficacy of its Emblem Subcutaneous Implantable Defibrillator (S-ICD) system. The Marlborough, MA-based company revealed results from the UNTOUCHED study at the 2019 Heart Rhythm Society annual meeting.

UNTOUCHED study results show that S-ICD therapy had a complication-free rate of 95.8% at 30 days post-procedure and high conversion efficacy 99.2% of induced ventricular fibrillation. Results from the study also show that 69% of the procedures were performed using a two-incision technique, which led to lead to faster surgeries when compared to a three-incision technique.

And nearly a year ago, Medtronic said that instead of using a transvenous approach for ICD therapy, it is looking at an extravascular method. The Dublin-based company started a pilot study of its Extravascular Implantable Cardioverter Defibrillator (EV ICD) system, in which a lead is placed outside of the heart and veins to deliver lifesaving defibrillation and antitachycardia pacing therapy all in one system.