Functional status and quality of life in patients with heart failure undergoing coronary bypass surgery after assessment of myocardial viability

OBJECTIVES. The aim of this study was to evaluate whether preoperative clin ical and test data could be used to predict the effects of myocardial revas cularization on functional status and quality of life in patients with hear t failure and ischemic LV dysfunction. BACKGROUND. Revascularization of viable myocardial segments has been shown to improve regional and global LV function. The effects of revascularizatio n on exercise capacity and quality of life (QOL) are not well defined. METHODS. Sixty three patients (51 men, age 66 +/- 9 years) with moderate or worse LV dysfunction (LVEF 0.28 +/- 0.07) and symptomatic heart failure we re studied before and after coronary artery bypass surgery. All patients un derwent preoperative positron emission tomography (PET) using FDG and Rb-82 before and after dipyridamole stress; the extent of viable myocardium by P ET was defined by the number of segments with metabolism-perfusion mismatch or ischemia. Dobutamine echocardiography (DbE) was performed in 47 patient s; viability was defined by augmentation at low dose or the development of new or worsening wall motion abnormalities. Functional class, exercise test ing and a QOL score (Nottingham Health Profile) were obtained at baseline a nd follw-up. RESULTS. Patients had wall motion abnormalities in 83 +/- 18% of LV segment s. A mismatch pattern was identified in 12 =/- 15% of-LV segments, and PET evidence of viability was detected in 30 +/- 21% of the LV Viability was re ported in 43 +/- 18% of the LV by DbE. The difference between pre- and post operative exercise capacity ranged from a reduction of 2.8 to an augmentati on of 5.2 METS. The degree of improvement of exercise capacity correlated w ith the extent of viability by PET (r = 0.54, p = 0.0001) but not the exten t of viable myocardium by DbE (r = 0.02, p = 0.92). The area under the ROC curve for PET (0.76) exceeded that for DbE (0.66). In a multiple linear reg ression, the extent of viability by PET and nitrate use were the only indep endent predictors of improvement-of exercise capacity (model r = 0.63, p = 0.0001). Change in Functional Class correlated weakly with the change in ex ercise capacity (r = 0.25), extent of viable myocardium by PET (r = 0.23) a nd extent of viability by DbE (r = 0.31). Four components of the quality of life score (energy, pain, emotion and mobility status) significantly impro ved over follow-up, but no correlations could be identified between quality of life scores and the results of preoperative testing or changes in exerc ise capacity. CONCLUSIOINS. In patients with LV dysfunction, improvement of exercise capa city correlates with the extent of viable myocardium. Quality of life impro ves in most patients undergoing revascularization. However, its measurement by this index does not correlate with changes in other parameters nor is i t readily predictable. (C) 1999 by the American College of Cardiology.