title: Effects of smoking on coronary blood flow velocity and coronary flow reserve assessed by transthoracic Doppler echocardiography.
abstract: BACKGROUND
  Smoking is a well-known risk factor for cardiovascular disease. Coronary blood flow velocity (CFV) can be measured directly with transthoracic Doppler echocardiography (TTDE) which is conducted immediately after smoking.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the chronic and acute effects of smoking on coronary blood flow and coronary flow reserve (CFR) by the use of TTDE.
  
  
  METHODS
  Healthy volunteers (11 smokers and 9 nonsmokers) with a mean age of 27 +/- 3 years were included. Smoking was abstained for at least 4 hours before the study. CFV was measured at the distal left anterior descending coronary artery by TTDE at baseline and during intravenous adenosine infusion (140 microg/kg per minute) in all participants. For smokers, CFV was measured immediately after consecutively smoking two cigarettes and during adenosine infusion.
  
  
  RESULTS
  CFR and coronary vascular resistance index (CVRI) showed no significant difference between nonsmokers and smokers (CFR: 3.5 +/- 0.8 vs 3.6 +/- 0.6, P = ns, CVRI: 0.28 vs 0.28, P = ns) at baseline. CFR significantly decreased (3.6 +/- 0.6 to 2.8 +/- 0.7, P = 0.008) and CVRI markedly increased (0.28 to 0.35, P = 0.012) after smoking.
  
  
  CONCLUSIONS
  After 4 hours of abstinence from smoking, CFR and CVRI in smokers were similar to those of nonsmokers. However, consecutively smoking two cigarettes acutely reduced CFR and increased CVRI. These findings suggested that smoking could reduce coronary blood flow immediately, even in healthy people.
authors.affiliation: Division of Cardiology, Korea University Hospital, Seoul, Korea.
authors.forename: Seong-Mi
authors.initials: SM
authors.lastname: Park
authors.forename: Wan-Joo
authors.initials: WJ
authors.lastname: Shim
authors.forename: Woo-Hyuk
authors.initials: WH
authors.lastname: Song
authors.forename: Do-Sun
authors.initials: DS
authors.lastname: Lim
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Kim
authors.forename: Young-Moo
authors.initials: YM
authors.lastname: Ro
mesh_terms: D000241:Adenosine; D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D015150:Echocardiography, Doppler; D006801:Humans; D008297:Male; D012907:Smoking / Q000009:adverse effects*; D018709:Statistics, Nonparametric; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine