Effects of cardiac rehabilitation as independent predictor for favourable long term postoperative evolution in patients undergoing coronary artery bypass grafting

Aim: 1. To evaluate whether a supervised cardiac rehabilitation (CR) program improves physical capacity and quality of life (QoL) of patients with LV systolic dysfunction undergoing coronary artery bypass grafting (CABG) compared to patients training by their own. 2. To investigate LV diastolic function dynamics according to the results of tissue Doppler imaging (TDI) in these patients. 3. To define the echographic predictors for long term prognosis in these patients and their adjusted value for calculation of a preoperative risk score. Material and method: Prospective randomized study on 665 CABG patients with LV systolic dysfunction (LVEF<35%), comparing 12 weeks of supervised exercise training (SET) 3 times per week to home-based training based upon public health recommendations of minimum level of physical activity. Patients were evaluated including TDI preoperatively and till 5 years postoperatively. The primary endpoints were the composites of death from any cause or hospitalization for cardiac causes and the secondary endpoints were changes in peak oxygen uptake and in physical capacity (measured with cardiopulmonary exercise testing), changes in healthrelated QoL and changes in physical activity level (measured with International Physical Activity Questionnary). Stastistical analysis used SYSTAT and SPSS programs. Results: 1. SET was more efficient in rehabilitating CABG patients being an independent predictor for a more favourable postoperative evolution, mostly in patients with normal LV diastolic filling pattern (LVDFP) (97,27%) compared with restrictive LV filling (89.83%). At 5 years postoperatively, cardiovascular event-free survival was significantly higher in nonrestrictive LVDFP group (74.94%) compared with restrictive LVDFP (55,75%). 2. Conventional transmitral diastolic Doppler indices before and after CABG remained unchanged. TDI showed significant improvement in SET group at 3 and 12 months postoperatively of both LV systolic (S: 6.1±0.9, 7.5±1.1 and 7.3±1.2cm/s) and diastolic function (e': 7.2±1.8, 8.3±1.4 and 8.8±1.5cm/s.; E/e' ratio: 17.8±2.1, 13.1±1.7 and 11.3±1.8; Vp 3.2±0.55, 2.4±0.28 and 1.9±0.26) 3. The main predictors for unfavorable evolution at 5 years postoperatively were: age >75 years (RR=7.3), LV end-systolic volume (LVESV) >85cm3 (RR=6.4), restrictive LVDFP (RR=8.9) and pulmonary hypertension (PHT) (RR=5.2). Conclusions: 1. SET improves physical capacity and QoL in CABG patients, mainly in those with normal LVDFP, the restrictive LVDFP being associated with an early and late postoperative unfavourable evolution and difficult CR. 2. Exercise capacity and symptoms are more closely correlated with indices assessed by TDI which demonstrate significant improvement of LV systolic and diastolic function in SET patients, regardless of transmitral flow pattern 3. On long term postoperatively the unfavorable evolution was predicted by: age>75 years, LVESV>85cm3, restrictive LVDFP and severe PHT.