Improvement of severely reduced left ventricular function after surgical revascularization in patients with...

Area of Science:

• Cardiology
• Nuclear Medicine
• Cardiac Surgery

Background:

• Myocardial stunning and hibernation describe viable but depressed heart muscle function.
• Coronary artery bypass grafting (CABG) is a treatment for ischemic heart disease.
• Assessing left ventricular (LV) function and identifying viable myocardium preoperatively is crucial for surgical success.

Purpose of the Study:

• To assess postoperative LV function after CABG in patients with previous myocardial infarction and impaired preoperative LV function.
• To evaluate the role of positron emission tomography (PET) in identifying reversible ischemic myocardium.
• To determine the predictive value of PET findings for postoperative functional improvement.

Main Methods:

• Studied 23 patients with preoperative LV function <45%.
• Performed echocardiography and cardiac catheterization pre- and postoperatively.
• Utilized preoperative PET imaging (82Rubidium-2-fluoro-2-desoxyglucose) to assess myocardial viability.

Main Results:

• CABG significantly improved resting and exercise LV systolic and diastolic function in 21 patients with patent grafts.
• Ejection fraction (EF) improved from 34% to 52% at rest and 31% to 58% during exercise (P<0.01).
• PET identified hibernating myocardium, correlating with improved regional contractility post-CABG.

Conclusions:

• CABG effectively restores LV function in selected patients with ischemic cardiomyopathy.
• PET is valuable for preoperative identification of hibernating myocardium and predicting functional recovery after revascularization.
• Successful revascularization improves both global and regional LV contractility.