Objectives: Decreased right ventricular (RV) longitudinal function following coronary artery bypass grafting (CABG), as assessed by tricuspid annular systolic excursion (TAPSE) and RV peak systolic velocity (RVS') is a known condition. We aimed to explore the feasibility of the right ventricular index of myocardial performance (RIMP) in the assessment of RV function after CABG at rest and during peak dobutamine stress echocardiography (DSE).
Methods: Forty-two patients indicated for CABG were included in this study. Coronary angiography, DSE and exercise bicycle test were performed within 6 weeks before and 3 months after CABG. The RIMP, RVS' and TAPSE at the lateral tricuspid annulus were also assessed. The results were presented as mean ± standard deviation.
Results: The RIMP improved after CABG both at rest (0.45 ± 0.11 before vs 0.38 ± 0.08 after CABG, P = 0.013) and during DSE (0.75 ± 0.23 vs 0.49 ± 0.14, P < 0.001). TAPSE declined significantly when comparing the values from before CABG to after CABG both at rest (23.9 ± 4.46 vs 14.6 ± 3.67, P < 0.001) and during DSE (20.9 ± 4.16 vs 11.9 ± 3.60, P < 0.001). RVS' also decreased after CABG both at rest (11.9 ± 2.40 vs 8.5 ± 1.93, P < 0.001) and during DSE (15.6 ± 4.30 vs 10.5 ± 3.21, P < 0.001). On the other hand, exercise capacity improved after CABG compared with baseline (128.4 ± 40.12 W vs 142.1 ± 46.73 W, P = 0.014).
Conclusions: RIMP improved after CABG both at rest and during DSE. The reduction in TAPSE and RVS' after CABG indicate reduced regional mechanical RV function along the long axis rather than reduced global RV function.