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Impact of Myocardial Hibernation and Scar on Benefits From CABG in Ischemic Left Ventricular Dysfunction
Shuyang Song1, Xu Han1, Xinghong Ma1
1Department of Nuclear Medicine, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Beijing, China.
Insights
Coronary artery bypass grafting (CABG) improves survival in ischemic left ventricular dysfunction (ILVD) patients. Myocardial hibernation and scar extent do not affect CABG
Area of Science:
- Cardiology
- Nuclear Medicine
- Cardiovascular Imaging
Background:
- Assessing myocardial viability is crucial for guiding coronary artery bypass grafting (CABG) in patients with ischemic left ventricular dysfunction (ILVD).
- The role of myocardial hibernation and scar burden in predicting CABG outcomes in ILVD remains debated.
Purpose of the Study:
- To investigate the impact of integrated myocardial hibernation and scar assessment on the survival benefits of CABG in ILVD patients.
- To determine if the extent of myocardial viability or scar influences CABG efficacy.
Main Methods:
- Retrospective analysis of 507 ILVD patients undergoing fluorine-18 fluorodeoxyglucose positron emission tomography and cardiac magnetic resonance imaging.
- Viability testing included late gadolinium enhancement to quantify myocardial scar and hibernation.
- Cox models were used to compare outcomes between CABG and medical therapy, analyzing subgroups based on hibernation and scar levels.
Main Results:
- CABG significantly reduced all-cause mortality (HR 0.249) and secondary composite outcomes (HR 0.457) compared to medical therapy alone.
- In a median follow-up of 71.5 months, 98 patients died and 194 reached secondary endpoints.
- Favorable outcomes with CABG were observed across all subgroups, irrespective of hibernation (10%) and scar (26%) levels.
Conclusions:
- The extent of myocardial hibernation and scar burden does not appear to modify the survival benefit of CABG in ILVD patients.
- Integrated assessment of myocardial viability and scar may not be necessary for treatment decisions in this population.
Background:
The significance of evaluating myocardial viability in making decisions regarding coronary artery bypass grafting (CABG) for patients with ischemic left ventricular dysfunction (ILVD) remains controversial. This study aimed to examine the impact of integrated assessment of hibernating myocardium and scars on the survival benefit associated with CABG in patients with ILVD.
Methods:
Consecutive patients with ILVD who underwent fluorine-18 fluorodeoxyglucose positron emission tomography and cardiac magnetic resonance imaging with late gadolinium enhancement viability testing from January 2015 and April 2018 were retrospectively enrolled. The primary end point was all-cause death. The secondary end point was a composite of cardiovascular death, cardiovascular hospitalization, heart transplantation, revascularization, insertion of an implantable cardioverter-defibrillator, or nonfatal stroke. Cox models calculated hazard ratios (HRs) and CIs for CABG vs medical therapy alone for subgroups with different levels of hibernation and scars.
Results:
During a median follow-up of 71.5 months in 507 patients, 98 patients reached the primary end point and 194 reached the secondary end point. After adjustment, CABG was associated with lower risks of all-cause mortality (HR, 0.249; 95% CI, 0.154-0.428; P<.001) and lower incidences of secondary outcomes (HR, 0.457; 95% CI, 0.318-0.658; P<.001) compared with medical treatment alone in the population. Across all 4 subgroups classified by the optimal cutoff value (10% hibernation and 26% scar), CABG was associated with favorable outcomes regardless of the hibernation and scar level.
Conclusions:
The extent and severity of hibernating myocardium and scars appear not to influence the effects of CABG in patients with ILVD.
