title: Dynamic change in collateral flow associated with myocardial ischemia in humans.
abstract: BACKGROUND
  This study sought to investigate how collateral flow changes during myocardial ischemia in patients.
  
  
  METHODS
  Myocardial contrast echocardiography (MCE) and rapid atrial pacing were performed in 20 patients with angiographically evidenced coronary collaterals from the right coronary artery (RCA) to the occluded left anterior descending coronary artery. Sonicated contrast medium was injected into the RCA before and immediately after atrial pacing to determine the peak background-subtracted contrast intensity (PI) in the collateral territory (PIA) and its ratio to PI in the control territory (PI ratio) as parameters of collateral blood flow. Lactate production in the coronary circulation during pacing was determined to assess myocardial ischemia in the collateral territory.
  
  
  RESULTS
  PIA showed a significant correlation with regional wall motion either before (r(squared)=-0.64, P<0.01) or after pacing (r(squared)=-0.65, P<0.01). Similarly, PI ratio was significantly correlated with regional wall motion either before (r(squared)=-0.54, P<0.05) or after pacing (r(squared)=-0.64, P<0.01). Rapid atrial pacing decreased both PIA and PI ratio significantly greater in patients with lactate production than in those without (PIA: -67+/-53 vs. -15+/-34%, P<0.05; PI ratio: -68+/-49 vs. -8.2+/-32%, P<0.05, respectively), while neither PIA nor PI ratio differ between the two groups of patients before pacing (PIA: 13.8+/-19. vs. 16.2+/-13.3U, P=0.75; PI ratio: 0.70+/-0.71 vs. 0.87+/-0.65, P=0.58, respectively).
  
  
  CONCLUSIONS
  We concluded that (1) collateral flow determined by MCE was closely associated with regional cardiac function, and (2) not the amount of collateral flow at rest, but pacing-induced change of collateral flow seemed to be a determinant of regional ischemia in patients with coronary collaterals.
authors.affiliation: Cardiovascular Division, Osaka Police Hospital, Osaka, Japan. sakatah@medone.med.osaka-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Sakata
authors.forename: M
authors.initials: M
authors.lastname: Kitakaze
authors.forename: F
authors.initials: F
authors.lastname: Ishikura
authors.forename: Y
authors.initials: Y
authors.lastname: Lim
authors.forename: A
authors.initials: A
authors.lastname: Hirayama
authors.forename: K
authors.initials: K
authors.lastname: Kodama
authors.forename: T
authors.initials: T
authors.lastname: Masuyama
authors.forename: T
authors.initials: T
authors.lastname: Kuzuya
authors.forename: M
authors.initials: M
authors.lastname: Hori
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D003097:Collateral Circulation / Q000502:physiology*; D003287:Contrast Media; D004452:Echocardiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology*
chemical_list: D003287:Contrast Media