- Poster presentation
Comparison of coronary endothelial function and brachial flow mediated vasodilatation using cardiac magnetic resonance imaging
Journal of Cardiovascular Magnetic Resonancevolume 11, Article number: P35 (2009)
Brachial artery flow-mediated dilatation (FMD) is used as a surrogate for invasive assessment of coronary artery endothelial function, concordance with invasive assessment of coronary endothelial function is controversial.
We assessed both brachial FMD and coronary CPT noninvasively at the same sitting using cardiac MRI (CMR) and compared the two in a population with and without coronary risk factors.
Endothelium-dependent vasodilator function was assessed in the brachial and coronary arteries in 39 subjects. Using a Siemens 1.5 T scanner, the left anterior descending (LAD) coronary artery was localized using a navigator angiographic sequence and a proximal cross-section imaged using TrueFISP bright blood imaging and T2 weighted turbo spin echo imaging. Images were obtained at rest and during cold pressor testing(CPT) and evaluated in ARGUS (Siemens). The % change in lumen cross-sectional area in mid diastole was determined. FMD was assessed by inflating a blood pressure cuff to a reading 50 mmHg higher than the subject's resting systolic pressure, and deflating after 1 min. Imaging was done using TrueFISP cine bright blood imaging at rest, inflation and at 5 sequential time points during deflation. Images were evaluated in ARGUS (Siemens). The % change in lumen cross-sectional area pre and post inflation was determined.
Of 39 subjects, 16 were females and the mean age was 52 ± 8 yrs. Coronary risk factors (hypertension, hyperlipidemia, smoking, diabetes) were present in 19 while 20 had no risk factors.
The mean brachial FMD of the pooled cohort was 13% and the mean coronary response to CPT was 16%. There was no significant relationship between the brachial FMD and coronary CPT response (r = 0.03, P = 0.8).
When determined with similar noninvasive methods at the same sitting, brachial FMD does not correlate closely with coronary endothelial response to CPT in a population with and without coronary risk factors. Use of brachial FMD as a surrogate for coronary endothelial function should be reconsidered.