title: Quantitative contrast echocardiographic assessment of collateral derived myocardial perfusion during elective coronary angioplasty.
abstract: OBJECTIVE
  To determine whether myocardial contrast echocardiography can be used to quantify collateral derived myocardial flow in humans.
  
  
  METHODS
  In 25 patients undergoing coronary angioplasty, a collateral flow index (CFI) was determined using intracoronary wedge pressure distal to the stenosis to be dilated, with simultaneous mean aortic pressure measurements. During balloon occlusion, echo contrast was injected into both main coronary arteries simultaneously. Echocardiography of the collateral receiving myocardial area was performed. The time course of myocardial contrast enhancement in images acquired at end diastole was quantified by measuring pixel intensities (256 grey units) within a region of interest. Perfusion variables, such as background subtracted peak pixel intensity and contrast transit rate, were obtained from a fitted gamma variate curve.
  
  
  RESULTS
  16 patients had a left anterior descending coronary artery stenosis, four had a left circumflex coronary artery stenosis, and five had a right coronary artery stenosis. The mean (SD) CFI was 19 (12)% (range 0-47%). Mean contrast transit rate was 11 (8) seconds. In 17 patients, a significant collateral contrast effect was observed (defined as peak pixel intensity more than the mean + 2 SD of background). Peak pixel intensity was linearly related to CFI in patients with a significant contrast effect (p = 0.002, r = 0.69) as well as in all patients (p = 0.0003, r = 0.66).
  
  
  CONCLUSIONS
  Collateral derived perfusion of myocardial areas at risk can be demonstrated using intracoronary echo contrast injections. The peak echo contrast effect is directly related to the magnitude of collateral flow.
authors.affiliation: Swiss Cardiovascular Centre Bern, University Hospital, CH-3010 Bern, Switzerland.
authors.forename: S F
authors.initials: SF
authors.lastname: de Marchi
authors.forename: M
authors.initials: M
authors.lastname: Schwerzmann
authors.forename: M
authors.initials: M
authors.lastname: Fleisch
authors.forename: M
authors.initials: M
authors.lastname: Billinger
authors.forename: B
authors.initials: B
authors.lastname: Meier
authors.forename: C
authors.initials: C
authors.lastname: Seiler
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000379:methods; D003287:Contrast Media; D003326:Coronary Circulation / Q000502:physiology*; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy; D004452:Echocardiography / Q000379:methods / Q000592:standards; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000592:standards; D011134:Polysaccharides; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508