Influence of patients' age at implantation on mortality and defibrillator shocks

Area of Science:

• Cardiology
• Geriatric Medicine
• Medical Device Technology

Background:

• Increasing comorbidities and competing mortality causes in aging populations raise questions about implantable cardioverter defibrillator (ICD) effectiveness in older adults.
• The balance of benefits and risks for ICD therapy may shift with advancing age.

Purpose of the Study:

• To investigate the impact of patient age at initial device implantation on all-cause mortality.
• To assess the effect of age on the risk of ICD shocks in recipients of single-chamber (V-ICD), dual-chamber (D-ICD), and cardiac resynchronization therapy defibrillator (CRT-D) devices.

Main Methods:

• Retrospective analysis of de-identified records from 67,128 ICD recipients in the Boston Scientific ALTITUDE database.
• Stratification of patients into V-ICD, D-ICD, and CRT-D groups.
• Evaluation of all-cause mortality and ICD shock risk over a mean follow-up of 2.3 years, analyzing the effect of age at implantation.

Main Results:

• Across all ICD types, older age was associated with increased all-cause mortality.
• Patients aged ≥80 years had a significantly higher mortality risk compared to those <50 years (6.8-fold for V-ICD, 5.9-fold for D-ICD, 3.4-fold for CRT-D).
• Conversely, increasing age correlated with a decreased risk of defibrillator shocks and/or anti-tachycardia pacing (31-53% reduction in older vs. youngest groups).

Conclusions:

• Older recipients of standard and CRT defibrillators face higher mortality but experience fewer shocks and/or therapies.
• These findings suggest diminished benefit from ICD therapy in older individuals, likely due to competing non-arrhythmic causes of mortality.
• The clinical utility of defibrillator therapy in the elderly warrants further investigation, potentially through randomized controlled trials.