Prediction by postexercise fluoro-18 deoxyglucose positron emission tomography of improvement in exercise capacity after revascularization

The extent of ischemic and hibernating myocardium, which may be detected by increased postexercise uptake of fluoro-18 deoxyglucose (FDG) using positron emission tomography, may determine the degree of functional benefit after revascularization. This study examined the influence of the amount of this FDG-avid myocardium on changes in left ventricular function and exercise parameters after revascularization. Echocardiography and exercise testing were performed before and after intervention in 23 patients who had undergone positron emission tomography for the evaluation of myocardial perfusion (using rubidium-82), and postexercise FDG imaging in the fasting state. Follow-up echocardiography (22 ± 14 weeks after revascularization) was compared with preoperative FDG activity in 7 myocardial regions per patient. Systolic function improved after intervention in 19 of 26 malperfused, dysfunctional FDG-avid regions (73%), and did not improve in 35 of 47 dysfunctional regions without increased FDG uptake (74%). The influence of the amount of FDG-avid tissue on changes in functional state was examined by comparing 9 patients with multiple (≥2) FDG-avid regions with the remainder. Those with multiple FDG-avid regions demonstrated improvement in peak rate-pressure product (20 ± 4 to 26 ± 4 × 10 3, p < 0.02), and percentage of maximal heart rate achieved at peak (84 ± 10% to 93 ±6%, p = 0.04), neither of which changed significantly in the remaining patients. Exercise capacity increased from 5.6 ± 2.7 to 7.5 ± 1.7 METS in the group with multiple FDG-avid regions; this increase of 55 ± 18% exceeded the increase of 13 ± 10% in the remainder (p = 0.04). Thus, imaging of postexercise FDG uptake in patients with previous myocardial infarction may predict improvement of regional systolic function and exercise parameters after revascularization.