Local coronary wall eccentricity and endothelial function are closely related in patients with atherosclerotic coronary artery disease

Abstract

BackgroundCoronary endothelial function (CEF) in patients with coronary artery disease (CAD) varies among coronary segments in a given patient. Because both coronary vessel wall eccentricity and coronary endothelial dysfunction are predictors of adverse outcomes, we hypothesized that local coronary endothelial dysfunction is associated with local coronary artery eccentricity.MethodsWe used 3 T coronary CMR to measure CEF as changes in coronary cross-sectional area (CSA) and coronary blood flow (CBF) during isometric handgrip exercise (IHE), a known endothelial-dependent stressor, in 29 patients with known CAD and 16 healthy subjects. Black-blood MRI quantified mean coronary wall thickness (CWT) and coronary eccentricity index (EI) and CEF was determined in the same segments.ResultsIHE-induced changes in CSA and CBF in healthy subjects (10.6 ± 6.6% and 38.3 ± 29%, respectively) were greater than in CAD patients 1.3 ± 7.7% and 6.5 ± 19.6%, respectively, p < 0.001 vs. healthy for both measures), as expected. Mean CWT and EI in healthy subjects (1.1 ± 0.3 mm 1.9 ± 0.5, respectively) were less than those in CAD patients (1.6 ± 0.4 mm, p < 0.0001; and 2.6 ± 0.6, p = 0.006 vs. healthy). In CAD patients, we observed a significant inverse relationship between stress-induced %CSA change and both EI (r = -0.60, p = 0.0002), and CWT (r = -0.54, p = 0.001). Coronary EI was independently and significantly related to %CSA change with IHE even after controlling for mean CWT (adjusted r = -0.69, p = 0.0001). For every unit increase in EI, coronary CSA during IHE is expected to change by -6.7 ± 9.4% (95% confidence interval: -10.3 to -3.0, p = 0.001).ConclusionThere is a significant inverse and independent relationship between coronary endothelial macrovascular function and the degree of local coronary wall eccentricity in CAD patients. Thus anatomic and physiologic indicators of high-risk coronary vascular pathology are closely related. The noninvasive identification of coronary eccentricity and its relationship with underlying coronary endothelial function, a marker of vascular health, may be useful in identifying high-risk patients and culprit lesions.

Astragaloside IV Improves Vasodilatation Function by Regulating the PI3K/Akt/eNOS Signaling Pathway in Rat Aorta Endothelial Cells

“…Endothelial-dependent coronary artery vasoreactivity is a significant indicator of vascular function [6,7]. Endothelial dysfunction is characterized by decreased nitric DOI: 10.1159/000489958 oxide (NO) bioavailability and predicts late cardiovascular events [8].…”

Precision and accuracy of cross‐sectional area measurements used to measure coronary endothelial function with spiral MRI

“…Area measurement precision and accuracy can be further improved with smaller acquisition voxels as long as the SNR remains above 30. Importantly, the currently used CEF‐MRI protocol distinguishes area changes of 4‐5% at SNR levels achieved in vivo. Noninvasive CEF measures by MRI promise a window into predicting atherosclerotic progression and testing new interventions.…”

“…Prior studies have shown isometric handgrip exercise induced mean coronary cross‐sectional area changes from 10–20% in healthy vessels and reduced dilation or even a paradoxical constriction from 2 to −12% in diseased vessels, approximately a 20% absolute difference in area change on average between healthy and diseased vessels. The ability to measure one‐fifth or a quarter of the difference between healthy and diseased enables the comparison of patient groups at earlier stages of atherosclerotic disease progression and the investigation of the impact of medical or lifestyle interventions on CEF where the improvement may only be a fraction of the difference measured between healthy and diseased vessels.…”

“…The isometric handgrip exercise induced area change measured with MRI ranges from 10–20% in healthy coronary arteries and exhibits reduced dilation or even a paradoxical constriction from 2 to –12% in impaired vessels . However, the cross‐sectional area change is on the order of only a few imaging voxels because MRI's sensitivity and time constraints lead to a limited spatial resolution.…”

“…Additionally, because most MRI CEF studies to date have been performed with spiral rather than radial MRI, the second goal of this work was to determine the precision and accuracy of coronary cross‐sectional area measurements, and the smallest detectable area change using spiral MRI with the identical phantom as was used in Yerly et al…”