Right Ventricular Dysfunction after Coronary Artery Bypass Grafting Is a Reality of Unknown Cause and Significance

Abstract

To evaluate the impact of coronary bypass surgery on the function of the right ventricle (RV) in patients with a pre-operative ejection fraction ≥ 35% who did not have any perioperative myocardial infarction. We performed a prospective study of 30 patients who underwent uneventful isolated coronary artery bypass grafting (CABG). All patients had echocardiography prior to surgery and 3 months postoperatively. Myocardial tissue Doppler velocities were used to measure left and right ventricular function. The right ventricular myocardial performance index (Tei) and the ratio between the velocities of the RV and left ventricle (LV) were also calculated. There was a significant improvement in left ventricular ejection fraction before and after CABG (P = .046). The tissue Doppler imaging (TDI) velocities from the LV remained unchanged, but highly significant reductions in right ventricular TDI velocities were observed (P <.001). The TDI peak systolic (S), early diastolic (E), and late diastolic (A) velocities had a reduction of 30%, 34.5%, and 20%, respectively. Similarly, a fall in RV to LV ratios of various TDI velocities was also observed. This was also accompanied by a significant rise in the RV Tei index. All of these findings are suggestive of significant RV dysfunction. There is a marked impairment of RV function after CABG.