title: A new angiographic method to assess coronary flow reserve-validation in humans.
abstract: BACKGROUND
  Coronary flow reserve (CFR) is defined as the ratio between coronary artery flow during maximal hyperemia and rest. It is considered as a marker for the integrity of the epicardial coronary circulation and the microcirculation. CFR measurement typically requires the introduction of a guide wire into a diseased coronary artery. We tested a new algorithm, which allows to estimate CFR by analysis of coronary angiograms without the need for direct intracoronary measurements.
  
  
  METHODS
  Twenty seven patients (10 female, mean age 64 +/- 11 years) underwent diagnostic cardiac catheterization for the evaluation of chest pain. A Doppler wire was introduced into the diseased coronary artery and CFR(doppler) was calculated by the flow velocity ratio between rest and maximal hyperemia, induced by intravenous administration of 140 microg of adenosine per kg bodyweight. This was compared to the angiographically determined CFR (CFR(angio)) under the same conditions (rest and induced maximal hyperemia) by densitometry. CFR(angio) was based on the creation of two time density curves representing the disappearance of contrast over time. CFR(angio) was the resulting ratio between the density values during hyperemia and rest.
  
  
  RESULTS
  An excellent correlation was found between CFR(doppler) and CFR(angio): CFR(angio) = 1 x CFR(doppler) (r = 0.87; P < 0.0001). The average absolute difference between both indeces was 0.36 +/- 0.31.
  
  
  CONCLUSIONS
  Measurement of CFR(angio) by densitometry is feasible and provides results, which are comparable to Doppler-derived intracoronary flow velocity measurements.
authors.affiliation: Medizinische Klinik II, Klinikum Coburg gGmbH, Coburg, Germany. rittger@arcor.de
authors.forename: Harald
authors.initials: H
authors.lastname: Rittger
authors.forename: Asher
authors.initials: A
authors.lastname: Kuper
authors.forename: Ole-Alexander
authors.initials: OA
authors.lastname: Breithardt
authors.forename: Eberhardt
authors.initials: E
authors.lastname: Kuon
authors.forename: Martin
authors.initials: M
authors.lastname: Schmidt
authors.forename: Anil-Martin
authors.initials: AM
authors.lastname: Sinha
authors.forename: Barbara
authors.initials: B
authors.lastname: Blüm
authors.forename: Axel
authors.initials: A
authors.lastname: Jakob
authors.forename: Johannes
authors.initials: J
authors.lastname: Brachmann
mesh_terms: D000241:Adenosine; D000328:Adult; D000368:Aged; D000465:Algorithms; D001783:Blood Flow Velocity; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003326:Coronary Circulation; D015150:Echocardiography, Doppler; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D014665:Vasodilator Agents / Q000627:therapeutic use
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine