title: The effect of ischemia and reperfusion on microvascular function: a human in vivo comparative study with conduit arteries.
abstract: Although microvascular dysfunction is of critical importance in the pathophysiology of myocardial ischemic syndromes, no study has investigated whether there are differences in the sensitivity to ischemia and reperfusion injury between microvessels and conduit arteries. Ten healthy young nonsmoking male volunteers (age range 24-45) were enrolled. Parameters measured included radial (conduit) artery (endothelium-dependent) flow-mediated dilation, microvascular cutaneous reactive hyperemia (using laser Doppler) and acetylcholine-induced microvascular vasodilation (laser Doppler iontophoresis). Data were acquired before and after ischemic injury (15 minutes of ischemia of the brachial artery followed by 15 minutes reperfusion) and analyzed in a randomized, blinded fashion. Conduit artery FMD was significantly blunted after ischemia (before: 7.5 +/- 1.1%; after: 2.9 +/- 1.0%, P < 0.05). Conversely, ischemia had no effect on microvascular reactive hyperemia (P = ns) and acetylcholine-induced vasodilation (P = ns). Using a human in vivo model, we demonstrate that microvessels are more resistant to ischemic injury as compared to conduit arteries.
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: John D
authors.initials: JD
authors.lastname: Parker
authors.forename: Sandro
authors.initials: S
authors.lastname: Forconi
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D000704:Analysis of Variance; D006801:Humans; D007478:Iontophoresis / Q000379:methods; D017078:Laser-Doppler Flowmetry / Q000379:methods; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D017534:Radial Artery / Q000502:physiology*; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology*; D015427:Reperfusion Injury / Q000097:blood*; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D000109:Acetylcholine