Myocardial Viability and Long-Term Outcomes in Ischemic Cardiomyopathy

Area of Science:

• Cardiology
• Cardiac Surgery
• Medical Imaging

Background:

• The benefit of assessing myocardial viability to guide surgical revascularization in ischemic cardiomyopathy is debated.
• The link between improved left ventricular function post-revascularization and patient outcomes is unclear.

Purpose of the Study:

• To investigate the role of myocardial viability assessment in identifying patients with ischemic cardiomyopathy who may benefit from coronary artery bypass grafting (CABG).
• To determine the relationship between left ventricular function improvement and long-term outcomes after CABG.

Main Methods:

• 601 patients with coronary artery disease and low ejection fraction (<35%) underwent myocardial viability assessment (SPECT, dobutamine echo, or both).
• Patients were randomized to CABG plus medical therapy or medical therapy alone.
• Primary endpoint was all-cause mortality, with a median follow-up of 10.4 years.

Main Results:

• CABG plus medical therapy significantly reduced all-cause mortality compared to medical therapy alone (HR 0.73; 95% CI, 0.60-0.90).
• No significant interaction was found between myocardial viability and the survival benefit of CABG.
• Left ventricular ejection fraction improved only in patients with viable myocardium, irrespective of treatment, but this did not correlate with survival.

Conclusions:

• Myocardial viability assessment does not appear to be associated with long-term benefits of CABG in ischemic cardiomyopathy.
• While viable myocardium improves systolic function, this functional improvement does not translate to better long-term survival after revascularization.