title: Prevalence and predictors of slow flow in angiographically normal coronary arteries.
abstract: BACKGROUND
  One out of 5 patients undergoing coronary angiography has angiographically normal coronary arteries (ANCA). Some of them have abnormally slow coronary flow (SCF). The prevalence and causes of SCF in these patients are not clear.
  
  
  METHODS
  We studied 114 consecutive patients with ANCA. Each angiogram was independently evaluated by 2 physicians unaware of all other clinical features of the case. Coronary flow (CF) was graded using the corrected TIMI Frame Count (cTFC) and Coronary Clearance Frame Count (CCFC) methodologies. SCF was defined as a cTFC exceeding the reported normal (mean cTFC + 2 SD) in each of the three major coronary arteries. The association between SCF and various clinical, inflammatory, and metabolic variables was tested using a multivariable analysis model.
  
  
  RESULTS
  Thirty-nine (34%) patients had SCF. Inter-individual CF varied substantially among them (range 10-143 frames/sec, mean: 37 ± 22 frames/sec). The intra-individual CF did not vary: CF correlated well in the three major epicardial coronary arteries of a given individual (r = 0.7, p = 0.0001). Multivariable analysis revealed that current smoking was the most significant variable related to SCF (odds ratio = 4.7, p = 0.006, CI 95% 1.6-13.3). The SCF group included significantly more smokers (41% versus 15%, p = 0.002).
  
  
  CONCLUSIONS
  SCF is a common finding (34%) among patients with angiographically normal coronary arteries. In these patients, slow flow is a systemic phenomenon that involves all three coronary arteries rather than a local event and is associated with current smoking.
authors.affiliation: Departments of Cardiology, Tel Aviv Sourasky Medical Center, Affiliated to The Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Yaron
authors.initials: Y
authors.lastname: Arbel
authors.forename: Efrat
authors.initials: E
authors.lastname: Rind
authors.forename: Shmuel
authors.initials: S
authors.lastname: Banai
authors.forename: Amir
authors.initials: A
authors.lastname: Halkin
authors.forename: Shlomo
authors.initials: S
authors.lastname: Berliner
authors.forename: Itzhak
authors.initials: I
authors.lastname: Herz
authors.forename: Noa
authors.initials: N
authors.lastname: Mashav
authors.forename: Tamar
authors.initials: T
authors.lastname: Thurm
authors.forename: Gad
authors.initials: G
authors.lastname: Keren
authors.forename: Ariel
authors.initials: A
authors.lastname: Finkelstein
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000503:physiopathology; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012907:Smoking / Q000009:adverse effects* / Q000503:physiopathology