Abstract 5733: Coronary Flow Reserve obtained by Transthoracic Echocardiography in Patients with Normal Coronary Arteries and Systolic Dysfunction, Normal Function and Coronary Artery Disease and Normal Function and Normal Coronary Arteries
Coronary Flow Reserve (CFR) has already been shown a reliable marker of physiological significance of coronary artery disease (CAD) and has recently been demonstrated to be an independent predictor of events in patients with dilated cardiomyopathy (DCM). Objective: To determine CFR in patients (pts) with DCM without obstructive CAD and in pts with normal systolic function and with obstructive CAD.
Methods: We prospectively studied 67 pts with normal systolic function (mean age 46+/− 12 years, 48% male, left ventricular ejection fraction (EF) >65%) and 47 pts with DCM (mean age 59 +/− 11 years, 52% male, EF<35%) who underwent coronary angiography within 6 months from stress echocardiography. Diastolic velocity flow in the mid left anterior descending coronary artery was obtained by transthoracic echocardiography with use of intravenous commercially available contrast agent (Definity, Bristol-Myers Squibb) at baseline and during adenosine infusion (140 mcg/Kg/min, for 6 minutes). CFR was determined as the ratio of peak diastolic velocity in hyperemic/baseline conditions. All pts underwent quantitative coronary angiography (QCA).
Results: Feasibility for assessing CFR was 83% in pts with normal function and 91% in DCM. Among the 56 pts in the final study with normal function, 25 had significant CAD and 31 had normal coronary arteries. Peak diastolic velocities in each group are described in Table⇓. CFR was 2.86+/−0.58 ín pts with normal function and no CAD, 1.57+/−0.32 in pts with normal function and CAD, and 2.14+/−0.49 in pts with DCM and no CAD (p<0.01 between groups). Sensitivity, specificity and accuracy for detecting CAD in pts with normal function was 96%, 94% and 95%, respectively. However, when considering the group with DCM, sensitivity was 74%, specificity 66% and accuracy 69%.
Conclusions: CFR can accurately detect pts with CAD when systolic function is normal. Pts with DCM have diminished CFR that lowers the predictive value of this parameter to detect CAD.