The MRI evaluation of nitric-oxide mediated systemic endothelial function and coronary endothelial function in healthy subjects and patients with coronary artery disease

Micaela Iantorno,Michael Schär,Robert Weiss,Allison Hays,Angela M Steinberg,Matthias Stuber,Gary Gerstenblith,Sahar Soleimanifard

doi:10.1186/1532-429x-17-s1-o52

Abstract

Background Endothelial cell release of nitric oxide (NO) is one indicator of vascular health. Coronary arteries develop atherosclerotic disease, while left internal mammary arteries (IMA), which are frequently used as bypass conduits in patients with disease, do not. Endothelial cell function of vessels can be assessed by the response to isometric handgrip exercise (IHE); normal function is evidenced by an increase in cross sectional area(CSA), flow velocity(FV) and blood flow(BF), and an abnormal response by no increase in these variables. Recently, the combination of coronary MRI and isometric handgrip exercise (IHE) was shown to noninvasively quantify coronary endothelial function (CEF). We tested the hypotheses that: 1) IMA vasoreactivity to IHE is measurable using coronary 3T MRI 2) endothelial function of IMA differs from that of coronary arteries in patients with coronary atherosclerotic disease (CAD) whereas in healthy subjects endothelial function of the two vascular beds is similar and 3) the IMA response to IHE is primarily mediated by NO, thus reflecting endothelial function.

Highlights

Endothelial cell release of nitric oxide (NO) is one indicator of vascular health
In the same CAD patients, in contrast, the IMA significantly dilated with IHE (p
In contrast to the RCA responses, the CSA changes in the IMA in the healthy individuals and CAD patients did not differ, the IMA FV and BF responses did (Fig 1B)

Summary

Background

Endothelial cell release of nitric oxide (NO) is one indicator of vascular health. Coronary arteries develop atherosclerotic disease, while left internal mammary arteries (IMA), which are frequently used as bypass conduits in patients with disease, do not. Endothelial cell function of vessels can be assessed by the response to isometric handgrip exercise (IHE); normal function is evidenced by an increase in cross sectional area(CSA), flow velocity(FV) and blood flow(BF), and an abnormal response by no increase in these variables. The combination of coronary MRI and isometric handgrip exercise (IHE) was shown to noninvasively quantify coronary endothelial function (CEF). We tested the hypotheses that: 1) IMA vasoreactivity to IHE is measurable using coronary 3T MRI 2) endothelial function of IMA differs from that of coronary arteries in patients with coronary atherosclerotic disease (CAD) whereas in healthy subjects endothelial function of the two vascular beds is similar and 3) the IMA response to IHE is primarily mediated by NO, reflecting endothelial function. In 9 healthy subjects, the role of NO in the IMA response to IHE was assessed during infusion of the NO synthase inhibitor, monomethyl-L-arginine(L-NMMA,0.3mg/kg/min)

Results

Methods

Conclusions