Evaluating endothelial function of the common carotid artery: an in vivo human model.
OBJECTIVE
Flow mediated dilation (FMD) of peripheral conduit arteries is a well-established tool to evaluate endothelial function. The aims of this study are to apply the FMD model to cerebral circulation by using acetazolamide (ACZ)-induced intracranial vasodilation as a stimulus to increase common carotid artery (CCA) diameter in response to a local increase of blood flow velocity (BFV).


RESULTS
In 15 healthy subjects, CCA end-diastolic diameter and BFV, middle cerebral artery (MCA) BFV and mean arterial blood pressure (MBP) were measured at basal conditions, after an intravenous bolus of 1g ACZ, and after placebo (saline) sublingual administration at the 15th and 20th minute. In a separate session, the same parameters were evaluated after placebo (saline) infusion instead of ACZ and after 10 microg/m(2) bs and 300 microg of glyceryl trinitrate (GTN), administered sublingually, at the 15th and 20th minute, respectively. After ACZ bolus, there was a 35% maximal MCA mean BFV increment (14th minute), together with a 22% increase of mean CCA end-diastolic BFV and a CCA diameter increment of 3.9% at the 3rd minute (p=0.024). There were no MBP significant variations up to the 15th minute (p=0.35). After GTN administration, there was a significant increment in CCA diameter (p<0.00001).


CONCLUSIONS
ACZ causes a detectable CCA dilation in healthy individuals concomitantly with an increase in BFV. Upon demonstration that this phenomenon is endothelium dependent, this experimental model might become a valuable tool to assess endothelial function in the carotid artery.
Mazzucco
S
S
Department of Neurological and Visual Sciences, Section of Clinical Neurology, University of Verona, Policlinico GB Rossi, Piazzale LA Scuro 10, 37134 Verona, Italy. sara.mazzucco@univr.it
Bifari
F
F
Trombetta
M
M
Guidi
G C
GC
Mazzi
M
M
Anzola
G P
GP
Rizzuto
N
N
Bonadonna
R
R
D000086:Acetazolamide / Q000494:pharmacology; D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D017536:Carotid Artery, Common / Q000187:drug effects / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D020768:Middle Cerebral Artery / Q000187:drug effects / Q000502:physiology; D005996:Nitroglycerin / Q000494:pharmacology; D012016:Reference Values; D012039:Regional Blood Flow; D014664:Vasodilation / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology; D055815:Young Adult
D014665:Vasodilator Agents; D005996:Nitroglycerin; D000086:Acetazolamide