Modeling defibrillation benefit for survival among cardiac resynchronization therapy defibrillator recipients
Kenneth C Bilchick1, Yongfei Wang2, Jeptha P Curtis2
1Department of Medicine(,) University of Virginia Health System, Charlottesville, VA.
Insights
Certain heart failure patients may not benefit from implantable cardioverter defibrillators (ICDs). Models can identify candidates for cardiac resynchronization therapy (CRT) who may not need ICD functionality, optimizing treatment.
Area of Science:
- Cardiology
- Medical Devices
- Health Outcomes
Background:
- Implantable cardioverter defibrillators (ICDs) are used in heart failure (HF) patients.
- However, not all patients, particularly those with a low risk of sudden arrhythmic death, may benefit from ICDs.
Purpose of the Study:
- To validate predictive models for identifying cardiac resynchronization therapy (CRT) candidates.
- To determine which CRT candidates might not require the defibrillator functionality in their devices.
Main Methods:
- Analysis of 60,185 HF patients from multiple registries and trials.
- Utilized multivariable Cox regression with the Seattle Heart Failure Model (SHFM) and Seattle Proportional Risk Model (SPRM).
- Compared outcomes for patients with CRT-defibrillators (CRT-Ds), non-CRT ICDs, and no device.
Main Results:
- CRT-D patients showed significant survival benefit compared to no device.
- Patients with high predicted survival (SHFM ≥81%) and low arrhythmic death risk (SPRM ≤42%) had minimal additional benefit from ICD functionality (0.95%/year).
- The majority of survival benefit in this low-risk group (70%) was from CRT pacing alone.
Conclusions:
- The SPRM and SHFM identified a significant proportion (25%) of primary prevention CRT-D patients with minimal ICD benefit.
- Further research is warranted to explore the use of CRT pacemakers (without ICD) in these selected low-risk patients.
Background:
Patients with heart failure having a low expected probability of arrhythmic death may not benefit from implantable cardioverter defibrillators (ICDs).
Objective:
The objective was to validate models to identify cardiac resynchronization therapy (CRT) candidates who may not require CRT devices with ICD functionality.
Methods:
Heart failure (HF) patients with CRT-Ds and non-CRT ICDs from the National Cardiovascular Data Registry and others with no device from 3 separate registries and 3 heart failure trials were analyzed using multivariable Cox proportional hazards regression for survival with the Seattle Heart Failure Model (SHFM; estimates overall mortality) and the Seattle Proportional Risk Model (SPRM; estimates proportional risk of arrhythmic death).
Results:
Among 60,185 patients (age 68.6 ± 11.3 years, 31.9% female) meeting CRT-D criteria, 38,348 had CRT-Ds, 11,389 had non-CRT ICDs, and 10,448 had no device. CRT-D patients had a prominent adjusted survival benefit (HR 0.52, 95% CI 0.50-0.55, P < .0001 versus no device). CRT-D patients with SHFM-predicted 4-year survival ≥81% (median) and a low SPRM-predicted probability of an arrhythmic mode of death ≤42% (median) had an absolute adjusted risk reduction attributable to ICD functionality of just 0.95%/year with the majority of survival benefit (70%) attributable to CRT pacing. In contrast, CRT-D patients with SHFM-predicted survival
Conclusions:
The SPRM and SHFM identified a quarter of real-world, primary prevention CRT-D patients with minimal benefit from ICD functionality. Further studies to evaluate CRT pacemakers in these low-risk CRT candidates are indicated.
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