title: Quantitative assessment of coronary microvascular function in patients with and without epicardial atherosclerosis.
abstract: The influence of atherosclerosis and its risk factors on coronary microvascular function remain unclear as current methods of assessing microvascular function do not specifically test the microcirculation in isolation. We examined the influence of epicardial vessel atherosclerosis on coronary microvascular function using the index of myocardial resistance (IMR).
  
  
  
  IMR (a measure of microvascular function) and fractional flow reserve (FFR, a measure of the epicardial compartment) were measured in 143 coronary arteries (116 patients). Fifteen patients (22 arteries, mean age 48+/-16 years) had no clinical evidence of atherosclerosis (control group). One hundred and one patients (121 arteries, mean age 63+/-11 years) had established atherosclerosis and multiple cardiovascular risk factors (atheroma group). Mean IMR in the control group (19+/-5, range 8-28) was significantly lower than in the atheroma group (25+/-13, range 6-75) (P<0.01). However, there was large overlap between IMR in both groups, with 69% of IMR values in patients with atheroma being within the control range. Mean FFR was also higher in the control group (0.96+/-0.02, range 0.93-1.00) than in the atheroma group (0.85+/-0.14, range 0.19-1.00) (P<0.01). There was no correlation between IMR and FFR (r=0.09; P=0.24), even when results in the control (r=0.02; P=0.92) and atheroma (r=0.15; P=0.10) groups were analysed in isolation. Using stepwise multiple regression analysis presence/absence of atheroma (ss=0.42; P=0.02) was the only independent determinant of IMR.
  
  
  
  Mean IMR is higher in patients with epicardial atherosclerosis. However, there is a large overlap between IMR in patients with and without epicardial atherosclerosis.
authors.affiliation: Cardiovascular Center, OLV Hospital, Aalst, Belgium.
authors.forename: Narbeh
authors.initials: N
authors.lastname: Melikian
authors.forename: Stephen
authors.initials: S
authors.lastname: Vercauteren
authors.forename: William F
authors.initials: WF
authors.lastname: Fearon
authors.forename: Thomas
authors.initials: T
authors.lastname: Cuisset
authors.forename: Philip A
authors.initials: PA
authors.lastname: MacCarthy
authors.forename: Giedrius
authors.initials: G
authors.lastname: Davidavicius
authors.forename: Wilbert
authors.initials: W
authors.lastname: Aarnoudse
authors.forename: Jozef
authors.initials: J
authors.lastname: Bartunek
authors.forename: Marc
authors.initials: M
authors.lastname: Vanderheyden
authors.forename: Eric
authors.initials: E
authors.lastname: Wyffels
authors.forename: William
authors.initials: W
authors.lastname: Wijns
authors.forename: Guy R
authors.initials: GR
authors.lastname: Heyndrickx
authors.forename: Nico H J
authors.initials: NH
authors.lastname: Pijls
authors.forename: Bernard
authors.initials: B
authors.lastname: de Bruyne
mesh_terms: D000328:Adult; D000368:Aged; D006328:Cardiac Catheterization; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000503:physiopathology*; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000503:physiopathology*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D010496:Pericardium; D012044:Regression Analysis; D018570:Risk Assessment; D012307:Risk Factors; D014655:Vascular Resistance; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents