Risk stratification for a primary prevention ICD: Performance of the MADIT-ICD Benefit Score in contemporary real world patients
Authors: Goldenberg I , Dzikowicz D , Zareba W , Mcnitt S , Scleede S , Polonsky S , Aktas M 
Published: October 2024

Abstract

Background
We have recently developed the MADIT-ICD Benefit Score to improve risk stratification for primary implantable cardioverter defibrillator (ICD) implantation by assessing the competing risk of life-threatening ventricular tachyarrhythmia (VTA) vs. non-arrhythmic mortality based using simple clinical variables. Patients with a MADIT-ICD Benefit Score of &lt; 50 are more likely to experience non-arrhythmic mortality than life-threatening VTA, and therefore derive limited benefit from a prophylactic ICD.

Purpose
We aimed to provide data on the performance of the MADIT-ICD Benefit Score in a real world population, comprising patients with HFrEF and either ischemic or nonischemic cardiomyopathy (ICM/NICM) who are treated with contemporary guideline-directed medical therapy (GDMT).

Methods
The study population comprised 2875 patients who were implanted with a primary prevention ICD and prospectively followed in a large tertiary healthcare system (the University of Rochester Medical Center, including 3 affiliated hospitals in Upstate New York) between 2017 through 2023. Arrhythmic events were captured from device interrogation data, which were blindly adjudicated by 2 electrophysiologists.

Results
Among the 2875 study patients, mean age was 62 ± 15 years, 1265 (44%) were women, and 1667 (58%) had ICM. Guideline-directed medical therapies, including angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, angiotensin receptor/neprilysin inhibitors, beta-blockers, mineralocorticoid receptor antagonists, and sodium-glucose transport protein 2 (SGLT2) inhibitors, were prescribed to 43%, 36%, 96%, 67% and 32% of study patients, respectively. The 2-year cumulative incidence of VTA, after accounting for the competing risk of death, was 19% vs. 11% in patients with a Score of ≥50 vs. &lt;50, respectively (p&lt;0.001; Figure 1A). Findings regarding ICD shocks were consistent (8% vs. 4%, respectively, p&lt;0.001; Figure 1B) The rate of VTA events at 4 years was directly correlated with increasing quartiles of the MADIT-ICD Benefit Score, while the corresponding rates of non-arrhythmic mortality were inversely correlated with score quartiles (Figure 1C). A similar direct correlation with increasing Benefit Score quartiles was observed when the endpoint of ICD shocks was assessed (Figure 1D). Accordingly, the benefit of the ICD (calculated as the difference between predicted rates of VTA/shock events and corresponding rates of non-arrhythmic mortality) was attenuated with decreasing quartiles of the MADIT-ICD Benefit Score (Figures 1C and 1D; right column).

Conclusions
We show good performance of the MADIT-ICD Benefit Score in a large cohort of real world ICD recipients who are treated with contemporary GDMT. These data support the use of the MADIT-ICD Benefit Score for improved risk stratification and for shared decision-making in contemporary candidates for a primary prevention ICD.