Abstract 13781: Assessment of Microvascular Dysfunction by Transthoracic Echocardiography Compared to Positron Emission Tomography
Introduction: Microvessel dysfunction can be assessed by measurement of Coronary Flow Reserve (CFR) by Transthoracic Doppler Echocardiography (TTDE). Positron Emission Tomography (PET) is regarded as the gold standard for CFR measurements. Only one previous study based on 10 healthy males has validated TTDE against PET measured CFR. The aim of the study was to compare CFR measurements by TTDE to those obtained by PET in women with angina pectoris but no obstructive coronary artery disease (CAD).
Methods: Patients (n=93) were randomly selected from a cohort of women with angina pectoris but no obstructive CAD and a successful CFR measurement by TTDE of the left anterior descending artery (LAD) during dipyridamole infusion (0.84 mg/kg). CFR was measured by rubidium-82 PET during adenosine infusion (0.84 mg/kg). A Quality Index (QI) of CFR measured by TTDE was assessed on a scale from 1-9 on the basis of visibility of vessel and characteristics of flow curves. Concordance between the methods was assessed by the Bland Altman method.
Results: CFR was successfully measured in 88 women by rubidium PET (exclusion due to inability to complete examination (n=4) and one outlier with un-physiological high CFR value of 5.9). Median CFR (iq range) was 2.69 (2.24; 3.05) for PET and 2.36 (1.92; 2.75) for TTDE. CFR was systematically assessed higher by PET (mean difference 0.39, p<0.01. Reproducibility was compared to a large study (n=125) regarding PET-PET agreement (table 1).
Conclusions: Results are similar to previous assessments of reproducibility of CFR assessed by PET. For patients with TTDE CFR QI > 6 there is a higher concordance between TTDE and PET CFR, indicating that the validity of CFR is dependent on quality. However, part of the divergence between PET and TTDE could be due to difference in method; TTDE estimates LAD flow velocities whereas PET estimates global flow per myocardial tissue mass. CFR measured with TTDE is a valid method to investigate cardiac microvascular dysfunction.
Author Disclosures: M.M. Michelsen: None. N.D. Mygind: None. A.A. Pena: None. R.H. Olsen: None. N. Høst: None. T.E. Christensen: None. P. Hasbak: None. A. Kjaer: None. J. Kastrup: None. E. Prescott: None.
- © 2014 by American Heart Association, Inc.