Long-Term Complications From Subcutaneous ICDs Assessed

Marilynn Larkin

August 02, 2021

NEW YORK (Reuters Health) — Using real-world patient data, researchers documented long-term complications from subcutaneous implantable cardioverter defibrillators (S-ICDs).

The study followed the US Food and Drug Administration's Class I recall (https://bit.ly/3ieIojg) of Boston Scientific's S-ICD subcutaneous electrode (Model 3501) because of the risk of fractures distal to the proximal sense ring, according to Dr. Allesio Gasperetti of Luigi Sacco University Hospital in Milan and colleagues.

As reported in Heart Rhythm, the team studied 1,254 patients (median age, 52; 77.6% male, 30.9% ischemic) implanted with S-ICDs from 2015 to 2020 in a multicenter European registry. The last follow-up of device-related complications was done after the Boston Scientific recall.

Over a median follow-up of 23.2 months, complications were observed in 117 patients (9.3%), for a total of 127 device-related complications (23.6% managed conservatively; 76.4% requiring reintervention).

Twenty-seven patients (2.2%) had an unanticipated generator replacement after 3.6 years, while four (0.3%) had a lead rupture. Factors associated with an increased risk of complications were BMI (hazard ratio, 1.063), chronic kidney disease (HR, 1.960), and oral anticoagulation (HR, 1.437)

By contrast, older age (HR, 0.980) and procedure performed in high-volume centers (HR, 0.463) were protective.

Early unanticipated battery depletion occurred in 2.2% of patients, while lead fracture was observed rarely (0.3%).

The authors note, "Pocket hematomas were very strong predictors of more severe infective complications in an S-ICD recipient, regardless of their conservative management or a reintervention. This finding is in line with what has been observed in transvenous (TV)-ICDs, which present significantly increased risks of infection requiring hospitalization due to pocket infection, bacteremia or endocarditis... Our data did highlight a strong (link) between significant pocket hematomas and subsequent infection for S-ICD, similarly to the 7-fold increased for TV-ICD observed in the BRUISE registry."

Dr. Luigi Di Biase, Director of Arrhythmia Services, Montefiore-Einstein Center for Heart and Vascular Care in New York City, commented in an email to Reuters Health, "The study shows worse results than the Praetorian randomized study (S-ICD vs. TV-ICD), but this is a real-life setting and not a trial."

"At the current time, high-volume centers should be preferred to low-volume centers," he said. "Although the Praetorian and Untouched trial using the SMART PASS reported a lower incidence of inappropriate shocks, this study showed a higher incidence, and therefore I believe improvements to further reduce inappropriate ICD shocks are necessary."

"The recall on the unanticipated generator replacement seems to be in line with the one reported by the company and therefore not alarming for patients," he added.

"Despite not being free from complications, S-ICD complication management seems less dangerous when looking at composite cardiovascular outcomes when compared to TV-ICD," Dr. DiBiase concluded.

Dr. Alexandru Costea of the University of Cincinnati College of Medicine, who is Director of the Electrophysiology Center in the UC Heart, Lung and Vascular Institute, commented by email, "It is important to realize that while very concerning for patients and medical communities, device recalls are rather frequent. Moreover, industry standards have been designed in such a manner that any potential impact on patients is minimized significantly."

"Therefore, while this study sheds some light on the usage of these subcutaneous defibrillators and their potential associated risks, it does not have a direct impact on patient care, clinical practice and/or research," he said. "Even in this study, it became evident that these defibrillators have a better safety profile than the traditional type when it comes to heart perforation and infections."

"It is nevertheless very important for heart healthcare providers to remain informed of any potential recalls or official statements from industry partners, as well as clinical research data to provide the best care," he noted. "Additionally, physicians have a moral obligation to report any concerns with technology in general, and more specifically, technology that has been recently developed."

The study received no funding; however, three coauthors have received fees from Boston Scientific. The authors did not provide a comment.

SOURCE: https://bit.ly/3rGHXkZ Heart Rhythm, online July 13, 2021.