Coronary Flow Reserve of the Non-Ischemia Related Coronary Artery During Dobutamine Stress Echocardiography

Abstract

BackgroundIncorporation of analysis of coronary velocities in stress studies adds diagnostic value to both clinical variables and dobutamine echocardiography. Micorcirculatory abnormalities may precede obstructive corornary disease. Therefore the aim of this study was to assess Doppler derived coronary velocity and flow of the left anterior descending coronary artery (LAD) during dobutamine stress echocardiography (DSE) in patients without LAD-related ischemia.MethodsSixty nine patients with chest pain underwent DSE studies to evaluate myocardial ischemia. All had trans-thoracic Doppler interrogation of the distal LAD before and just after termination of the DSE. Coronary velocity reserves (CFR) were calculated as the ratios of post-DSE/baseline diastolic velocities. Volumetric flow in the distal LAD was calculated from the diameter of LAD color jet and velocity integral. Volumetric flow reserve was calculated as the ratio of post-DSE baseline LAD flows.ResultsAt rest all subjects had left ventricular wall motion score index (WMSI) = 1, while in 28, wall motion abnormality appeared in non-LAD territory with WMSI = 1.17 ± 0.08. Peak diastolic velocity after DSE increased form 28.5 ± 13.6 to 52.4 ± 23.7 cm/sec, P = 9.5 × 10-11, and velocity-CFR was 2.08 ± 0.7. Diastolic LAD flow increased from 36.5 ± 23.8 to 75.75 ± 48.7 mL/min, P = 1.21 × 10-7 and volumetric-CFR was 2.6 ± 2.8. Peak diastolic velocity-CFR in patients without LV wall motion abnormality was 2.4 ± 0.7 while in those with motion abnormality 1.77 ± 0.56, P = 0.00008. Flow-derived LAD-CFR was 3.3 ± 3.7 in those without compared to 1.88 ± 0.57 in patients with wall motion abnormality, P < 0.05.ConclusionLAD velocity and flow reserves are reduced in patients with remote myocardial ischemia, which may indicate early atherosclerotic involvement.

Left anterior descending coronary artery flow after primary angioplasty in acute anterior ST-elevation myocardial infarction: How much flow is needed for left ventricular functional recovery?

“…18 Noninvasively determined LAD coronary artery flow was also important in the evaluation of coronary flow reserve. 19 The findings of the present study highlight further the importance of this kind of evaluation.…”

Differences in Coronary Artery Blood Velocities in the Setting of Normal Coronary Angiography and Normal Stress Echocardiography

“…Thus, apparently, absence of myocardial ischemia defines a normal coronary artery. However, in a previous study, it was shown that patients with remote ischemia had lower coronary flow reserve compared to subjects without ischemia ( 28 ). Therefore, absence of ischemia on stress echocardiography defines a normal coronary artery when confounding conditions associated with vasodilatation of the distal coronary bed and hyperemia are absent.…”