title: Coronary artery flow velocity is related to lumen area and regional left ventricular mass.
abstract: BACKGROUND
  Coronary flow velocity varies widely between individuals, even at rest. Because of this variation, indices with less apparent deviation, such as the ratio of hyperemic to resting velocity (coronary flow reserve), have been more commonly studied. We tested the hypothesis that the flow continuity principle could be used to model resting coronary flow, and we examined the resulting velocity relationship.
  
  
  RESULTS
  We studied coronary velocity in 59 patients using a Doppler wire to measure resting and hyperemic average peak velocities in the left anterior descending artery. Quantitative techniques were used to calculate lumen cross-sectional area and the lengths of all distal coronary branches. Branch lengths were used to estimate regional left ventricular mass. We then calculated the ratio of lumen area to regional mass (A/m). Regional perfusion was estimated from the double product of heart rate and systolic blood pressure. Resting velocity (V) varied inversely with A/m ratio [V=46.5/(A/m); r=0.68, P<0.001]. Disease in the left anterior descending artery was categorized as none or luminal irregularities only (n=22), mild (n=15), or moderate (n=22). The A/m ratio declined across these groups (8.7+/-4.0, 8.5+/-6.2, and 5. 6+/-3.0 mm(2)/100 g, respectively; P<0.04), and the resting average peak velocity increased (27+/-16, 33+/-11, and 37+/-20 cm/s, respectively; P=0.06).
  
  
  CONCLUSIONS
  Resting coronary artery flow velocity is inversely related to the ratio of lumen area to regional left ventricular mass. Higher resting velocities are found when insufficient lumen size exists for the distal myocardial bed, as occurs with diffuse mild or moderate coronary atherosclerosis.
authors.affiliation: University of Texas Health Science Center and Hermann Hospital, Houston 77225, USA. skipand@heart.med.uth.tmc.edu
authors.forename: H V
authors.initials: HV
authors.lastname: Anderson
authors.forename: M J
authors.initials: MJ
authors.lastname: Stokes
authors.forename: M
authors.initials: M
authors.lastname: Leon
authors.forename: S A
authors.initials: SA
authors.lastname: Abu-Halawa
authors.forename: Y
authors.initials: Y
authors.lastname: Stuart
authors.forename: R L
authors.initials: RL
authors.lastname: Kirkeeide
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003326:Coronary Circulation / Q000502:physiology*; D015150:Echocardiography, Doppler; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged