For older adults, similar outcomes for subcutaneous vs. transvenous ICDs
Among adults aged at least 65 years, treatment with a subcutaneous or single-chamber transvenous implantable cardioverter defibrillator was associated with similar outcomes, including all-cause and CV rehospitalization and death.
“Prior research has established the subcutaneous ICD as a reasonable alternative to the transvenous ICD in younger patients,” Daniel J. Friedman, MD, assistant professor of medicine at Duke University Hospital, told Healio. “There has been uncertainty regarding whether this was the case in older patients, particularly as older patients are more likely to develop an indication for backup pacing. The results from this study reassure that overall, the subcutaneous ICD can be a good option in appropriately selected older patients.”
Friedman and colleagues compared outcomes data among 16,063 Medicare beneficiaries who received a subcutaneous ICD or a single-chamber transvenous ICD implant from September 2012 to December 2017, using data from the National Cardiovascular Data Registry ICD Registry. The mean age of patients was 73 years, 28% were women and mean ejection fraction was 28.3%. The primary outcome was all-cause mortality; secondary outcomes included device reoperation, device removal for infection, device reoperation without infection and CV admission. The median follow-up was 2.3 years.
No difference in outcomes
Compared with patients with transvenous ICDs (n = 15,072), patients with subcutaneous ICDs (n = 991) were more often Black (18.1% vs. 12.4%), younger (mean age, 71 years vs. 73 years) and receiving dialysis (22.9% vs. 2.1%) and were less likely to have a history of atrial fibrillation or flutter (26.9% vs. 33.4%).
“Subcutaneous ICD was more common later in the study period, increasing from 1.1% of all study patients in 2013 to 8.1% of all study patients in 2017,” the researchers wrote.
In an unadjusted analysis, death was more common among the subcutaneous ICD group compared with the transvenous ICD group (log rank P < .002). In adjusted analyses, the researchers did not observe between-group differences for all-cause mortality (HR = 1.02; 95% CI, 0.819-1.27), device reoperation (HR = 0.976; 95% CI, 0.645-1.479), device removal for infection (HR = 0.614; 95% CI, 0.138-2.736), device reoperation without infection (HR = 0.975; 95% CI, 0.632-1.506), CV readmission (HR = 1.087; 95% CI, 0.912-1.295) or recurrent all-cause readmission (HR = 1.072; 95% CI, 0.99-1.161).
Friedman said longer-term follow-up is needed.
“The median follow-up in this study was 2.3 years,” Friedman told Healio. “The subcutaneous ICD battery is estimated to last around 7 years, compared with approximately 10 years or more with a transvenous ICD. That means patients who receive a subcutaneous ICD will need a generator replacement sooner than a transvenous ICD. While generator replacements are using straightforward procedures, there is an important risk for infection and there are limited data on outcomes after subcutaneous ICD generator replacement. Additionally, longer-term follow-up is needed to understand how often older patients require a device reoperation for addition of a transvenous pacing lead.”
Age bias ‘not warranted’
In a related editorial, Ahmadreza Karimianpour, DO, and Michael R. Gold, MD, PhD, both from the division of cardiovascular diseases at the Medical University of South Carolina in Charleston, wrote that the results support and extend previous studies suggesting that the age bias in subcutaneous ICD use is not warranted with contemporary ICD devices and programming.
“Hopefully we can treat older patients with a new trick of avoiding transvenous leads while still protecting from sudden cardiac death in the absence of pacing indications,” Karimianpour and Gold wrote.
For more information:
Daniel J. Friedman, MD, can be reached at firstname.lastname@example.org; Twitter: @danfriedmanmd.