title: Quantification of recruitable coronary collateral blood flow in conscious humans and its potential to predict future ischemic events.
abstract: OBJECTIVE
  The present study was designed to evaluate the applicability of a pressure-flow equation for quantitative calculation of recruitable collateral blood flow at coronary artery occlusion in conscious patients and to investigate the value of that index to predict future ischemic events.
  
  
  BACKGROUND
  Recent experimental studies have indicated that recruitable collateral blood flow at coronary artery occlusion can be expressed as a fraction of normal maximal myocardial blood flow by simultaneous recordings of mean arterial, coronary wedge and central venous pressures, respectively. This index is called the pressure-derived fractional collateral flow and is independent of hemodynamic loading conditions.
  
  
  METHODS
  In 120 patients undergoing elective coronary angioplasty, mean arterial, coronary wedge and central venous pressures were measured at balloon inflations of 2 min. All patients had a recent exercise electrocardiogram (ECG) with positive findings showing clearly distinguishable, reversible ECG abnormalities, enabling recognition of ischemia at balloon inflation. Fractional collateral blood flow at angioplasty was calculated by coronary wedge pressure minus central venous pressure divided by mean arterial pressure minus central venous pressure and correlated to the presence or absence of ischemia at balloon inflation. Ischemic events were monitored during a follow-up period of 6 to 22 months.
  
  
  RESULTS
  In 90 of the 120 patients, ischemia was present at balloon inflation, and in 82 of these patients, fractional collateral blood flow was < or = 23%. By contrast, in 29 patients, no ischemia was present, and fractional collateral blood flow was > 24% in all 29. During the follow-up period, 16 patients had an ischemic event. Fifteen of these 16 patients were in the group with insufficient collateral flow (p < 0.05).
  
  
  CONCLUSIONS
  To our knowledge, this study presents the first method for quantitative assessment of recruitable collateral blood flow in humans in the catheterization laboratory. Sufficient and insufficient collateral circulation can be reliably distinguished by this method. Use of this method can also help to provide more insight into the extent and behavior of the collateral circulation for investigational purposes and may have potential clinical implications.
authors.affiliation: Department of Cardiology, Catharina Hospital, Eindhoven, The Netherlands.
authors.forename: N H
authors.initials: NH
authors.lastname: Pijls
authors.forename: G J
authors.initials: GJ
authors.lastname: Bech
authors.forename: M I
authors.initials: MI
authors.lastname: el Gamal
authors.forename: H J
authors.initials: HJ
authors.lastname: Bonnier
authors.forename: B
authors.initials: B
authors.lastname: De Bruyne
authors.forename: B
authors.initials: B
authors.lastname: Van Gelder
authors.forename: H R
authors.initials: HR
authors.lastname: Michels
authors.forename: J J
authors.initials: JJ
authors.lastname: Koolen
mesh_terms: D000787:Angina Pectoris / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D015906:Angioplasty, Balloon, Coronary; D001794:Blood Pressure / Q000502:physiology; D006328:Cardiac Catheterization; D002496:Central Venous Pressure / Q000502:physiology; D003097:Collateral Circulation / Q000502:physiology*; D003243:Consciousness; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000453:epidemiology / Q000503:physiopathology*; D011237:Predictive Value of Tests; D013997:Time Factors