Coronary flow reserve assessment by dobutamine transesophageal doppler echocardiography

Objectives. This study attempted to determine the sensitivity and specificity of coronary flow reserve derived using transesophageal echocardiography for left anterior descending coronary artery stenosis. Background. Transesophageal echocardiography can be used to measure coronary flow velocity and may provide less invasive means of assessing coronary flow reserve. Methods. Seventy-eight adult patients were studied by pulsed Doppler transesophageal echocardiography of the proximal left anterior descending coronary artery during control period and peak (i.e, 40 μg/kg body weight per min) dobutamine infusion. Coronary flow reserve index was calculated as the ratio of maximal diastolic coronary velocity at peak dobutamine infusion to the control level and was considered abnormal if <1.81. Two-dimensional transesophageal left ventricular views were obtained for analysis of wall motion. Results. Coronary angiography showed ≥ 70% (group A, N = 18), >0% to <70% (group B, N = 21) and no (group C, N = 39) left anterior descending coronary artery diameter stenosis. An abnormal coronary flow reserve index did not differ from new regional wall motion abnormality in sensitivity for left anterior descending coronary stenosis in group (15 [83%] of 18 vs. 15 [83%] of 18, P = NS) but was significantly more sensitive in group B (12 [57%] of 21 vs. 2 [10%] of 21, p < 0.025). The specificity for no left anterior descending coronary stenosis in group C between normal coronary flow reserve index and no new regional wall motion abnormality did not differ (87% vs. 97%, P = NS). Conclusions. Doppler coronary flow reserve and two-dimensional dobutamine transesophageal echocardiography are equally sensitive for the detection of left anterior descending coronary stenosis ≥70% and equally specific. However, Doppler coronary flow reserve, compared with two-dimensional dobutamine transesophageal echocardiography, is more sensitive for intermediate left anterior descending coronary stenosis and may play significant adjunctive role to cardiac catheterization and other noninvasive techniques for assessing coronary artery disease.