What is the data for implanting primary prevention ICDs in older patients with heart failure?
Unlike some of my other questions, we have some data here! Looking back at seminal trials, the mean age of patients in MAD-IT II was 65 years, while the median age in SCD-HeFT was 60 years. With advancing age, incidence of co-morbidities generally rises, while expected life-years decline – which could argue against the benefit of a primary prevention device in this patient population. A pooled analysis of primary ICD trial data, which included 390 patients aged 75 years or older, demonstrated that the benefit of ICD on mortality persists even in older cohorts:
Figure 1. Unadjusted Kaplan–Meier survival curves by age groups
But, there are important caveats here. The benefit attenuates with age, and it becomes harder to rule out interactions above 70 years of age. The authors of this Circ article cite some data about the decreased utility of ICDs in American patients older than 84 and European patients older than 74 years. Similarly, a 2017 AHA/ACC/HRS Systematic Review showed mixed outcomes from several different trials, but ultimately a consensus on benefit:
Figure 2.5. Forest plot for ICD implantation in older patients (minimal overlap)
And there is one observational study that looked at matched patients older and younger than 80 years implanted with an ICD in France. This group found similar rates of appropriate therapies and complications in both groups (of note, there was a trend towards higher early complications in the older group, apparently driven by hematomas). Thirty-four percent of the older patients who died in the three years of follow-up had an appropriate device therapy delivered before their death.
Figure 1. The Kaplan–Meier curve illustrating freedom from appropriate therapies (A).
Interestingly, they do note that there were a lot of CRT devices placed in the older group, and that these patients generally had few comorbidities, limiting external validity. My overall take-home is that there is a role for this therapy provided that any potential patient above 70ish is on the healthier end of the spectrum.
Hess PL, Al-Khatib SM, Han JY, et al. Survival Benefit of the Primary Prevention Implantable Cardioverter-Defibrillator Among Older Patients. Circulation: Cardiovascular Quality and Outcomes. 2015;8(2):179-186. doi:https://doi.org/10.1161/circoutcomes.114.001306
Kusumoto FM, Bailey KR, Chaouki AS, et al. Systematic Review for the 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death. Circulation. 2018;138(13). doi:https://doi.org/10.1161/cir.0000000000000550
Zakine C, Garcia R, Narayanan K, et al. Prophylactic implantable cardioverter-defibrillator in the very elderly. EP Europace. 2019;21(7):1063-1069. doi:https://doi.org/10.1093/europace/euz041
