Evaluating real-world mortality risk after defibrillator implantation

Area of Science:

• Cardiology
• Medical Devices
• Biomarkers

Background:

• Implantable cardioverter-defibrillators (ICDs) are crucial for preventing sudden cardiac death (SCD) from ventricular arrhythmias.
• Current guidelines often contraindicate ICD implantation for patients with less than one year life expectancy.
• Assessing prognosis in ICD candidates remains challenging, potentially leading to suboptimal device selection.

Purpose of the Study:

• To evaluate outcomes of ICD recipients, focusing on early mortality (<12 months post-implant).
• To identify predictors of early death in ICD recipients, particularly non-arrhythmic causes.
• To explore the utility of biomarkers, such as red cell distribution width (RDW), in refining prognostic assessment for ICD candidates.

Main Methods:

• Retrospective analysis of 235 patients who received transvenous ICDs in 2015 for primary or secondary SCD prevention.
• Data collection included patient demographics, device information, and mortality outcomes over a mean follow-up of 66.2 months.
• Statistical analysis, including univariate and multivariate analyses and Receiver Operator Characteristic (ROC) curve analysis, was used to identify mortality predictors.

Main Results:

• Out of 235 patients, 77 (32.8%) died during follow-up; 20 (8.5%) died within 12 months post-implant.
• None of the early deaths were directly attributed to arrhythmias.
• Significant predictors of mortality included older age, ejection fraction <35%, and elevated red cell distribution width (RDW >14.75%).
• RDW demonstrated strong association with early mortality risk (p<0.001) with good diagnostic performance (AUC 0.75).

Conclusions:

• Current prognostic assessments for ICD candidates have limitations.
• Red cell distribution width (RDW) is a significant predictor of early, non-arrhythmic death in ICD recipients.
• Integrating biomarkers like RDW into clinical frailty scores could improve pre-assessment and risk stratification for ICD candidates.