OBJECTIVE: Patients with ischemic heart failure may benefit from coronary artery bypass grafting. The histopathological variables associated with improvement in ejection fraction 6 months after surgery were assessed. METHODS: This study comprised 24 patients indicated for coronary artery bypass grafting, ejection fraction < 35%, functional class II-IV heart failure, and mean age 59 ± 9 years. Endomyocardial biopsies were performed during and 6 months after surgery. Extension of the fibrosis, number of cells with myocytolysis, and hypertrophy of the muscle fiber were quantified by using a system of image analysis. Clinical and functional review was repeated within 6 months. RESULTS: A significant improvement in heart failure functional class was observed in 16 patients after 6 months of follow-up (from NYHA functional class 2.8±0.7 to 1.7±0.6; P <0.001), but the ejection fraction did not change (25±6 % vs. 26±10%). Hypertrophy of the muscle fiber was similar in the specimens biopsied in the pre- and postoperative periods (21±4 vs. 22± 4 µm), but the extension of fibrosis (8±8 vs. 21±15% area) and the number of cells with myocytolysis (9±11 vs. 21±15% cell) significantly increased. However, the composition of a histological score combining those 3 variables indicated a greater increase in the ventricular function of those with a lower degree of preoperative histopathological alterations. CONCLUSION: Patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting improved their ventricular function when the preoperative adverse histopathological alterations were of a lower degree.
heart failure; ischemic cardiomyopathy; endomyocardial biopsy; coronary artery bypass grafting
