Related Experiment Video
Updated: Jun 29, 2026
Surgical Swine Model of Chronic Cardiac Ischemia Treated by Off-Pump Coronary Artery Bypass Graft Surgery
Published on: March 27, 2018
Phenomapping the Response of Patients With Ischemic Cardiomyopathy With Reduced Ejection Fraction to Surgical
Tejus Satish1, Nicholas S Hendren1, Matthias Peltz1
1Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Insights
Coronary artery bypass grafting (CABG) benefits patients with heart failure and coronary artery disease, regardless of patient subgroup. These findings suggest CABG is a valuable treatment option across diverse patient phenotypes.
Area of Science:
- Cardiovascular Surgery
- Clinical Trials
- Heart Failure Research
Background:
- Coronary artery bypass grafting (CABG) improves survival in patients with heart failure with reduced ejection fraction (HFREF) and obstructive coronary artery disease (CAD).
- The impact of patient phenotypic heterogeneity on CABG benefits remains unclear.
- Investigating phenogroups can reveal differential risk profiles and treatment responses.
Purpose of the Study:
- To identify distinct patient phenogroups within the STICHES trial cohort using clustering analysis.
- To determine if these identified phenogroups exhibit different long-term risk profiles for mortality and cardiovascular events.
- To investigate whether the benefits of CABG vary across these phenogroups in patients with HFREF and CAD.
Main Methods:
- Clustering analysis was applied to the STICHES (Surgical Treatment for Ischemic Heart Failure Extension Study) derivation cohort (n=753) to identify phenogroups.
- Multivariable Cox models were used to assess long-term all-cause mortality, cardiovascular (CV) mortality, and a composite of mortality/CV hospitalization.
- Findings were internally validated on the STICHES validation cohort (n=459).
Main Results:
- Four distinct phenogroups were identified in the derivation cohort.
- The highest-risk phenogroup showed significantly increased risks for death (HR: 2.0) and CV death (HR: 2.0).
- Phenogroup assignment did not modify the beneficial effects of CABG on the studied outcomes (p > 0.05 for all).
Conclusions:
- The study identified distinct phenogroups in patients with HFREF and CAD, with varying risk profiles.
- Coronary artery bypass grafting (CABG) demonstrated consistent mortality benefits across all identified phenogroups.
- These findings support the use of CABG in selected patients with HFREF and CAD, irrespective of specific phenotypic characteristics.
Background:
Coronary artery bypass grafting (CABG) has demonstrated long-term mortality benefits in patients with HFREF and obstructive coronary artery disease (CAD), but whether phenotypic heterogeneity influences the benefits of CABG is unknown. We applied clustering analysis to STICHES (Surgical Treatment for Ischemic Heart Failure Extension Study) to identify phenogroups with different long-term risk profiles and investigate differences in CABG benefits between phenogroups.
Methods And Results:
STICHES was a randomized controlled trial evaluating the effect of CABG in addition to medical therapy versus medical therapy alone. We split the STICHES participants into derivation (n = 753) and validation (n = 459) cohorts. We phenomapped the derivation cohort using penalized model-based clustering. We fit multivariable Cox models to investigate long-term differences in all-cause mortality, cardiovascular (CV) mortality, and a composite of all-cause mortality/CV hospitalization between phenogroups and whether phenogroup assignment modified the effects of CABG on these outcomes. Findings were internally validated on the validation cohort. Four phenogroups were identified in the derivation cohort. The highest-risk group was at a twofold greater risk of death (HR: 2.0, 95% CI: 1.4-2.9, p < 0.001) and CV death (HR: 2.0, 95% CI: 1.3-3.1, p = 0.002), and a 1.5-fold greater risk for death/CV hospitalization (HR: 1.5, 95% CI: 1.1-2.1, p = 0.016). Phenogroup assignment did not modify the effects of CABG on the outcomes (p > 0.05 for all). Similar results were obtained in the validation cohort.
Conclusions:
The beneficial effects of CABG on all-cause mortality, CV mortality, and a composite of all-cause mortality and CV hospitalization persist despite phenotypic heterogeneity in HFREF and CAD.
Related Concept Videos
01:29Cardiomyopathy III: Hypertrophic Cardiomyopathy
01:29Cardiomyopathy V: Interprofessional Care