Assessment of Coronary Flow Reserve by Transesophageal Doppler Echocardiography

pp 65-75

Abstract

Objectives The aim of the study was to evaluate the value of measuring the basal coronary flow velocity and the maximal vasodilator reserve capacity with transesophageal Doppler from the left anterior descending artery. Material and methods We prospectively studied 30 patients (17 men; mean age, 64.8 ± 9.5 years). The coronary flow velocity was continuously monitored by pulsed wave Doppler in the proximal portion of the left anterior descending artery at baseline and during the hyperemic phase induced by the infusion of 0.14 mg/kg/min of adenosine for 2 min (20 patients) and 0.84 mg/kg of dipyridamole for 4 min (10 patients). The systolic and diastolic coronary reserve were calculated as the ratio between the maximal and the basal velocity measured (three cycles average:adenosine or dipyridamole/basal) from the evaluated period; these data were correlated with the coronary arteriography performed the week after the transesophageal Doppler. Results A good Doppler recording of blood flow velocity was obtained in all the patients. We compared the results of the patients with normal (group A = 20 patients) versus the remainder with significant disease (>_ 90%) (group B = 10 patients). The systolic basal velocity was x 20.1 ± 6 versus 29.6 ± 11.7 cm/sec (p < 0.007) and the diastolic 43.1 ± versus 66.9 ±29.7 cm/sec (p < 0.005). The systolic coronary flow velocity after vasodilators was 53.2 ± 16 in the group A versus 41.6 ± 13 cm/sec in the group B (p < 0.064) and the diastolic coronary flow velocity was 122.5 ± 37 versus 89.5 ± 36.1 cm/sec (p < 0.027). The hyperemic to baseline flow ratio was strikingly higher in patients without significant left anterior descending artery disease compared with the normals: systolic coronary reserve 2.87 ± 0.7 versus1.53 ± 0.45 cm/sec (p < 0.0001) and diastolic coronary reserve 2.94 ± 0.5 versus 1.54 ± 0.7 (p < 0.0001) respectively. A diastolic coronary reserve ratio >_ 2.3 was registered in 20/20 patients with normal left anterior descending artery (specifity of 100%) anda diastolic coronary reserve ratio <_ 1.4 in 9/10 patients with critical stenosis (sensitivity of 90%). Conclusions Coronary flow reserve by transesophageal Doppler echocardiography had proved very useful in the noninvasive evaluation of the territory of the left anterior descending coronary artery.