Primary vs Secondary Prevention Defibrillator Therapy in Octogenarians:
A Clinical Equipoise of Survival, Cost and Complications
Background: In the multiple trials that established the efficacy
of implantable cardiac defibrillator (ICD) in preventing sudden cardiac
death, patients aged ≥ 80 years were poorly represented. One aspect of
the paucity of data on outcomes in this subgroup pertains to any
difference in survival based on the indication for the device, i.e.
primary vs secondary prevention of ventricular arrhythmias.
Methods: We performed a monocentric retrospective observational
study of octogenarians receiving ICD therapy over a twelve-year period
(n=95). Fisher exact and Chi-squared tests were used for categorical
variables and student t-test and Wilcoxon rank-sum for continuous
variables. A Kaplan-Meier survival analysis using logrank test and an
adjusted Cox regression Hazard Ratio model was performed to compare
survival between primary and secondary prevention groups.
Results: Mean age of the cohort was 83.1 ± 3 years, with 85%
(n=81) being male. 73% (n=69) of the participants had ischaemic
cardiomyopathy and 43% (n=41) met the primary prevention indications.
Overall survival at 5 years was 80% with a median survival time post
device implantation at 27 months (IQR 12 – 55). The difference in
survival rates between primary and secondary prevention was not
statistically significant (p=0.63). Inappropriate shocks were delivered
in 2 patients while 14 patients were successfully treated with
appropriate therapy. Complications were encountered in 9.5% (n=9) of
cases. Conclusion: In carefully selected octogenarians, there is
no significant difference in the survival benefit conferred by ICD
therapy based on the indication for the device. Advanced chronological
age alone should not unduly influence the decision for ICD selection.
There is an imperative for a greater representation of this cohort in