Noninvasive assessment of coronary flow reserve in the right gastroepiploic artery graft

Background. To investigate the functional capacity of the right gastroepipl oic artery graft (GEA) and its ability to adapt to provide adequate flow at peak myocardial demand, we investigated the feasibility of determining cor onary now reserve (CFR) provided by this vessel using transabdominal color Doppler echocardiography and the correlation between this noninvasive deter mination of now reserve and nuclear stress scintigraphy. Methods. In 40 selected patients, who underwent complete arterial myocardia l revascularization using the GEA and the internal thoracic arteries (ITAs) , CFR of the GEA was measured at maximum coronary hyperemia induced by intr avenous adenosine infusion, 7 months (range 3 to 20) after surgery. In the same period, in 31 of this group Of patients, exercise thallium scintigraph y was performed. Results. We succeeded in measuring CFR in 37 of 40 patients with values ran ging from 1.1 to 3.6 with an average of 2.1 +/- 0.7. During adenosine infus ion, mean velocity in the GEA significantly increased from 48 +/- 20 to 89 +/- 41 cm/sec (p < 0.001), mean arterial. blood pressure significantly decr eased from 96 +/- 11 to 87 +/- 11 mm Hg (p < 0.001), and heart rate signifi cantly increased from 74 +/- 11 to 87 +/- 15 beats/min (p < 0.001). In 8 of these 37 patients, the nuclear exercise test was positive (compatible with reversible ischemia in the distribution area of the GEA). Average CFR in t hese 8 patients with positive nuclear stress test, was 1.46 +/- 0.28 versus 2.27 +/- 0.70 in those patients with a negative test (p < 0.001). Conclusions. Noninvasive determination of CFR of GEAs is feasible, using tr ansabdominal Doppler echocardiography. The present study shows that coronar y vasodilator reserve and autoregulation is maintained in myocardium suppli ed by the GEA and that the CFR has a significant correlation with the resul ts of noninvasive nuclear exercise testing Therefore, noninvasive determina tion of CFR by transabdominal Doppler echocardiography might be a valuable contribution to functional assessment of GEAs. (Ann Thorac Surg 2000;70:204 0-4) (C) 2000 by The Society of Thoracic Surgeons.