Abstract Background A new imaging metric using coronary computed tomography angiography (CCTA), addressing the peri–coronary adipose tissue (PCAT) computed tomography (CT) attenuation, has been clinically validated. This method provides information regarding coronary inflammation. It is unclear how coronary inflammation affects microvascular function. The non–invasive evaluation of coronary flowvelocity reserve is widely used in clinical practice using Doppler measurement on the left anterior descending coronary artery (CFVR–lad) during stress–echocardiography (SE).We hypothesize that coronary inflammation affects CFVR–lad and, in the absence of overt CAD, they are significantly correlated. Methods We evaluated the relationship between coronary inflammation (by PCAT CT attenuation) and coronary microvascular function (by CFVR–lad) in subjects with no or non–obstructive (diameter stenosis <70%) coronary artery disease (CAD). Results Two–hundred and two subjects were enrolled in the study. The relationship between PCAT CT attenuation and CFVR–lad show a significant inverse relationship in the entire group of subjects enrolled in the study (r = −0.32, p < 0.001). Correlation between PCAT CT attenuation and CFVR–lad was significant in subjects with no or mild CAD–lad, while this was not the case in subjects with intermediate CAD–lad. The R and R2 were respectively −0.40, −0.16 in subjects without CAD (p < 0.001) and − 0.35 and − 0.12 in subjects with mild CAD–lad (p = 0.001). Conclusions The main finding of the current study is the independent relationship between coronarymicrovascular function, by Doppler CFVR–lad during SE, in subjectswithout severely obstructive CAD in the left anterior descending coronary artery, and the level of local coronary inflammation, by PCAT attenuation measurement on CCTA.
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