title: Correlation analysis between different parameters of conduit artery and microvascular vasodilation.
abstract: Impaired endothelial responsiveness to specific vasodilator stimuli has been used as a surrogate marker of cardiovascular risk. Multiple methods allow testing endothelial responses in both microvessels and conduit arteries, but it is still unclear whether there is a relationship in endothelial function between these two different vascular beds. Twenty-five healthy young non smoking male volunteers (age range 24-45) were enrolled. Radial (conduit) artery (endothelium-dependent) flow-mediated dilation (FMD), microvascular cutaneous reactive hyperemia (using laser Doppler) and acetylcholine-induced microvascular vasodilation (laser Doppler iontophoresis) were measured. Data were analyzed in a randomized fashion in order to test the existence of a correlation among these measures of endothelium (in)dependent vasodilation. Conduit artery FMD showed a negative correlation with resting radial artery diameter (R=0.44, P<0.05). There was a correlation between peak responsiveness to acetylcholine and peak reactive hyperemia (R=0.41, P<0.05). Conversely, absolutely no correlation was shown between FMD and measures of microvascular vasomotion, including reactive hyperemia (P=ns) and acetylcholine-induced vasodilation (P=ns). Using three different human in vivo models, we test conduit artery and microvascular endothelial vasodilation. While microvascular flow reserve measurements induced by endothelium-dependent and independent stimuli appear to be linearly correlated, we show no correlation in endothelium-dependent vasomotion between the micro- and macrocirculation.
authors.affiliation: Department of Internal, Cardiovascular and Geriatric Medicine, University of Siena and Azienda Universitaria Ospedaliera Senese, Siena, Italy. tommaso.gori@utoronto.ca
authors.forename: Tommaso
authors.initials: T
authors.lastname: Gori
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Di Stolfo
authors.forename: Silvia
authors.initials: S
authors.lastname: Sicuro
authors.forename: Saverio
authors.initials: S
authors.lastname: Dragoni
authors.forename: Monica
authors.initials: M
authors.lastname: Lisi
authors.forename: John D
authors.initials: JD
authors.lastname: Parker
authors.forename: Sandro
authors.initials: S
authors.lastname: Forconi
mesh_terms: D000328:Adult; D015415:Biomarkers; D002318:Cardiovascular Diseases / Q000175:diagnosis; D004730:Endothelium, Vascular / Q000502:physiology* / Q000503:physiopathology; D006801:Humans; D006940:Hyperemia / Q000139:chemically induced*; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D011237:Predictive Value of Tests; D017534:Radial Artery / Q000187:drug effects / Q000502:physiology*; D012044:Regression Analysis; D012307:Risk Factors; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
chemical_list: D015415:Biomarkers