211 Dobutamine stress echo: concordance between wall motion assessment and non-invasively evaluated coronary flow reserve

Abstract

Aim: To assess consistency between left ventricular (LV) wall motion modification and coronary flow reserve in the left anterior descending coronary artery (LAD) territory during dobutamine stress-echo (DSE). Methods: 173 patients underwent DSE, according to the standard protocol, for evaluation of known or suspected coronary artery disease and, during the test, LAD flow velocity was measured at baseline and at peak stress. Segmental kinesis was evaluated both for all LV segments then limited to LAD territory (aWMSI). Coronary flow reserve (CFR) was calculated as the ratio between peak stress and baseline maximal diastolic velocity in the distal LAD. In a subgroup of 48 patients, without anterior myocardial infarction (MI), accuracy of non-invasively evaluated RFC was verified with coronary angiography data. Results: Patients were predominantly males (122.71%), mean age was 68±11 years; 69% were hypertensive, 37% diabetics, 46% presented dyslipidemia and 53% were smokers. Fifty-two patients had a recent or previous anterior MI, in 30 treated with primary PCI. Baseline echocardiography showed normal LV internal dimensions (end-diastolic volume index 63±20 ml/m 2 ; endsystolic volume index 34±18 ml/mq), with slightly reduced LV global systolic function (ejection fraction 47±27%). During ESD, both global WMSI then aWMSI resulted significantly and negatively correlated with RFC at baseline, after low dose and high dose dobutamine infusion; a similar correlation was also present between RFC and WMSI changes during high dose infusion, indicating extension of inducible ischemia. After exclusion of patients with anterior MI, these correlations remained significant; in the group with anterior MI, CFR was significantly and negatively correlated only with aWMSI after high dose infusion. Considering the final results of DSE and dividing patients in no or mild ischemia and extensive inducible ischemia (more than three LV segments), there was a significant difference in CFR value between the two groups (1.82 vs 2.26, p<0.001); otherwise presence or absence of viability didn’t influence CFR value. In absence of anterior MI, there was a good agreement between coronary angiography and noninvasively evaluated CFR (1.6 in patients with critical LAD stenosis vs 2.2 in patients with non critical lesions, p<0.05). Conclusion: LAD CFR evaluated during DSE demonstrates a good agreement with both LV segmental kinesis and coronary angiographic data, thus offering an adjunctive tool to improve DSE diagnostic accuracy.