Improving the Use of Primary Prevention Implantable Cardioverter-Defibrillators Therapy With Validated...

Area of Science:

• Cardiology
• Medical Devices
• Clinical Trials

Background:

• Guideline-recommended primary prevention implantable cardioverter-defibrillators (ICDs) are underutilized, with less than 50% of eligible patients receiving them.
• The Seattle Proportional Risk Model (SPRM) was previously developed to predict sudden death proportion in systolic heart failure patients without ICDs and validated in observational data.

Purpose of the Study:

• To evaluate if the validated SPRM can improve the identification of significant variations in expected implantable cardioverter-defibrillator (ICD) survival benefit.
• To test the SPRM's utility in a primary prevention ICD randomized trial.

Main Methods:

• Utilized data from the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT), a placebo-controlled trial involving 2,521 patients with ejection fraction ≤35% and symptomatic heart failure.
• Employed a Cox proportional hazards model to assess the relationship between patient-level SPRM predictions and ICD survival benefit, comparing SPRM to the Seattle Heart Failure Model.

Main Results:

• The SPRM demonstrated a significantly larger effect size (2- to 3.6-fold) in partitioning ICD treatment benefit compared to the Seattle Heart Failure Model.
• ICD benefit varied substantially across SPRM-predicted risk quartiles. For all-cause mortality, benefit ranged from a 10% increase in the highest risk quartile to a 66% decrease in the lowest risk quartile.
• For sudden death mortality, ICD therapy showed a 19% reduction in the highest risk quartile and a 95% reduction in the lowest risk quartile (p < 0.0001).

Conclusions:

• The SPRM serves as a valuable patient-centric tool for shared decision-making in symptomatic systolic heart failure patients who meet Class I criteria for primary prevention ICD therapy.
• The model effectively stratifies patients based on predicted risk, allowing for more personalized assessment of ICD therapy benefits.