Decreased right ventricular function after coronary artery bypass grafting and its relation to exercise capacity: a tricuspid annular motion-based study.

BACKGROUND

Decreased right ventricular (RV) function is a known echocardiographic finding after coronary artery bypass grafting (CABG). For patients with heart failure, RV dysfunction is a predictor of poor exercise capacity. The significance and time course of RV dysfunction and its relation to exercise capacity after CABG have not been elucidated, however.

OBJECTIVES

In this prospective study, we assessed RV function measured from echocardiographic tricuspid annular motion (TAM) before and after CABG and its relation to exercise capacity.

METHODS

In 99 patients accepted for CABG, we did a baseline echocardiographic investigation before operation, followed by repeated echocardiograms 3 months and 1 year after CABG. RV function was assessed using the magnitude of TAM measured at the RV free wall. An exercise stress test and coronary angiography were performed before and 3 months after CABG.

RESULTS

RV function assessed by TAM was significantly reduced 3 months after CABG (22.4 vs 14.5 mm, P <.001) compared with preoperative measurements and remained so after 1 year (14.7 mm, P <.001). Left ventricular systolic function was unchanged 3 months after CABG. The 1-year echocardiographic follow-up showed paradoxical septal movement in 96% of the patients. Exercise capacity improved significantly 3 months after CABG compared with before (1.6 vs 1.83 W/kg, P <.001). These finding are independent of the state of the right coronary artery.

CONCLUSIONS

One year after CABG, RV function remained depressed and septal motion remained paradoxical compared with the preoperative investigation, suggesting that these postoperative findings might be permanent in the majority of patients. Despite the reduced RV function, exercise performance 3 months after CABG was improved. The depressed RV function, measured from TAM after CABG, probably lacks clinical significance.