Did risk factors for non-benefit of implantable cardioverter defibrillator therapy change within the last decade?

Background: Throughout the last decades, studies have shown that ICD implantation provides overall prognostic benefits for patients at an increased risk of sudden cardiac death. However, comorbidities are becoming increasingly important for patient selection. The aim of this study is to assess the prognostic implications of comorbidities on ICD outcomes and to compare the trends in patient selection and outcomes over a decade-long period.

 

Methods: This study involved the analysis of 422 patients who received an ICD between 2011 and 2020. Patient information, comprising medical history, prescribed medications, laboratory results, ECG, and echocardiography data at the time of implantation, was collected. Subsequently, all patients underwent device assessments at our outpatient clinic six weeks post-implantation, followed by regular biannual examinations either at our outpatient clinic or at a cardiologist's office. The endpoint "no-benefit" was defined as death from any cause without prior appropriate ICD therapy. Conversely, benefit of ICD implantation was defined as receiving appropriate ICD therapy either before death or surviving until the end of the observation period.

 

Results: The study cohort was divided into groups with early ICD implantation (years 2011-2015, n=238) and late ICD implantation (years 2016-2020, n=183). The mean follow-up in the early implantation group was 4.5 ± 3.2 years and in the late implantation group 2.3 ± 1.7 years. No-benefit of ICD implantation was observed in 61 patients (26%) of the early group and in 23 patients (13%) in the late group. Benefit or neutral outcome was seen in 178 patients (74 %) of the early and in 160 (87%) of the late implantation group. Early implantation was significantly associated with no-benefit, but the one-, two- and three-year no-benefit rates were 7.1%, 8.4% and 12.1% in the early implantation group compared to 5.5%, 7.1% and 9.3% in the late implantation group, which demonstrated no significant difference between the two groups (p=0.493, p=0.632, p=0.353).

Multivariate analyses identified age ≥ 70 years (HR 2,756, p<0.001), atrial fibrillation (HR 2,278, p=0.003), peripheral artery disease (HR 2.263, p=0.017), and anemia (HR 2.998, p<0.001) as independent risk factors for non-benefit of ICD implantation in the early group, and age ≥ 66 years (HR 5.936, p=0.004), diabetes mellitus (HR 4.362, p=0.002), COPD (HR 4.194, p=0.003), and anemia (HR 2.482, p=0.036) as independent risk factors for non-benefit of ICD implantation in the late group.

 

Conclusion: This study is offering valuable insights into the changes and selection of ICD patient groups throughout the years. While the early implantation group had significantly higher rates of no benefit compared to the late implantation group, there were also fewer comorbidities associated with non-benefit in the late group compared to earlier years, suggesting a potential improvement in patient selection. This underlines the importance of careful patient selection and consideration of individual risk factors.