Endomyocardial biopsy foretells ventricular function recovery after coronary artery bypass grafting

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.

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.

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 microm), 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.

Patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting improved their ventricular function when the preoperative adverse histopathological alterations were of a lower degree.