title: Coronary flow reserve is impaired in patients with slow coronary flow.
abstract: BACKGROUND
  Slow coronary flow (SCF) in a normal coronary angiogram is a well-recognized clinical entity, but its etiopathogenesis remains unclear. However, previous studies have suggested that microvascular abnormalities and endothelial dysfunction responsible for SCF. Accordingly, we hypothesized that SCF phenomenon may be a form, at least early phase, of atherosclerosis that involve both small vessels and epicardial coronary arteries, and therefore we investigated coronary flow reserve (CFR) reflecting coronary microvascular function in patients with SCF.
  
  
  METHODS
  Twenty subjects with SCF and 15 control subjects with normal coronary flow were studied. Coronary flow was quantified according to TIMI frame count (TFC). Coronary diastolic peak flow velocities were measured at baseline and after dipyridamole infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocities.
  
  
  RESULTS
  Demographic features, coronary risk factors, echocardiographic measurements except diastolic function parameters, and biochemical measurements were similar between the groups. CFR values were significantly lower in subjects with SCF than in the control group (1.99+/-0.38 versus 2.99+/-0.47, P<0.0001). In addition, TIMI frame count independently correlated with CFR.
  
  
  CONCLUSIONS
  These findings suggest that CFR, which reflects coronary microvascular function, is impaired in patients with SCF, and corrected TFC well correlates with CFR.
authors.affiliation: Baskent University, Konya Teaching and Medical Research Center, Cardiology Department, Hoca Cihan Mah., Saray Cad., No.:1, Selcuklu, Konya, Turkey. aydoganer@yahoo.com
authors.forename: Dogan
authors.initials: D
authors.lastname: Erdogan
authors.forename: Mustafa
authors.initials: M
authors.lastname: Caliskan
authors.forename: Hakan
authors.initials: H
authors.lastname: Gullu
authors.forename: Alpay Turan
authors.initials: AT
authors.lastname: Sezgin
authors.forename: Aylin
authors.initials: A
authors.lastname: Yildirir
authors.forename: Haldun
authors.initials: H
authors.lastname: Muderrisoglu
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology*; D016022:Case-Control Studies; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000503:physiopathology*; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000503:physiopathology*; D015150:Echocardiography, Doppler / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged