title: Intracoronary Adenosine: Dose-Response Relationship With Hyperemia.
abstract: OBJECTIVE
  The present study sought to establish the dosage of intracoronary (IC) adenosine associated with minimal side effects and above which no further increase in flow can be expected.
  
  
  BACKGROUND
  Despite the widespread adoption of IC adenosine in clinical practice, no wide-ranging, dose-response study has been conducted. A recurring debate still exists regarding its optimal dose.
  
  
  METHODS
  In 30 patients, Doppler-derived flow velocity measurements were obtained in 10 right coronary arteries (RCAs) and 20 left coronary arteries (LCAs) free of stenoses >20% in diameter. Flow velocity was measured at baseline and after 8 ml bolus administrations of arterial blood, saline, contrast medium, and 9 escalating doses of adenosine (4 to 500 μg). The hyperemic value was expressed in percent of the maximum flow velocity reached in a given artery (Q/Qmax, %).
  
  
  RESULTS
  Q/Qmax did not increase significantly beyond dosages of 60 μg for the RCA and 160 μg for LCA. Heart rate did not change, whereas mean arterial blood pressure decreased by a maximum of 7% (p < 0.05) after bolus injections of IC adenosine. The incidence of transient A-V blocks was 40% after injection of 100 μg in the RCA and was 15% after injection of 200 μg in the LCA. The duration of the plateau reached 12 ± 13 s after injection of 100 μg in the RCA and 21 ± 6 s after the injection of 200 μg in the LCA. A progressive prolongation of the time needed to return to baseline was observed. Hyperemic response after injection of 8 ml of contrast medium reached 65 ± 36% of that achieved after injection of 200 μg of adenosine.
  
  
  CONCLUSIONS
  This wide-ranging, dose-response study indicates that an IC adenosine bolus injection of 100 μg in the RCA and 200 μg in the LCA induces maximum hyperemia while being associated with minimal side effects.
authors.affiliation: Cardiovascular Centre Aalst, OLV Clinic Aalst, Aalst, Belgium.
authors.forename: Julien
authors.initials: J
authors.lastname: Adjedj
authors.affiliation: Cardiovascular Centre Aalst, OLV Clinic Aalst, Aalst, Belgium.
authors.forename: Gabor G
authors.initials: GG
authors.lastname: Toth
authors.affiliation: Weatherhead PET Center for Preventing and Reversing Atherosclerosis, Division of Cardiology, Department of Medicine, University of Texas Medical School and Memorial Hermann Hospital, Houston, Texas.
authors.forename: Nils P
authors.initials: NP
authors.lastname: Johnson
authors.affiliation: Cardiovascular Centre Aalst, OLV Clinic Aalst, Aalst, Belgium.
authors.forename: Mariano
authors.initials: M
authors.lastname: Pellicano
authors.affiliation: Cardiovascular Centre Aalst, OLV Clinic Aalst, Aalst, Belgium.
authors.forename: Angela
authors.initials: A
authors.lastname: Ferrara
authors.affiliation: Cardiovascular Centre Aalst, OLV Clinic Aalst, Aalst, Belgium.
authors.forename: Vincent
authors.initials: V
authors.lastname: Floré
authors.affiliation: Cardiovascular Centre Aalst, OLV Clinic Aalst, Aalst, Belgium.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Di Gioia
authors.affiliation: Cardiovascular Centre Aalst, OLV Clinic Aalst, Aalst, Belgium.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Barbato
authors.affiliation: Department of Cardiology, Hopital Cantonal Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Olivier
authors.initials: O
authors.lastname: Muller
authors.affiliation: Cardiovascular Centre Aalst, OLV Clinic Aalst, Aalst, Belgium. Electronic address: bernard.de.bruyne@olvz-aalst.be.
authors.forename: Bernard
authors.initials: B
authors.lastname: De Bruyne
mesh_terms: D000241:Adenosine / Q000008:administration & dosage* / Q000009:adverse effects; D000368:Aged; D001783:Blood Flow Velocity; D003287:Contrast Media / Q000008:administration & dosage; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000503:physiopathology; D003326:Coronary Circulation / Q000187:drug effects*; D003331:Coronary Vessels / Q000187:drug effects* / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D013997:Time Factors; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D003287:Contrast Media; D014665:Vasodilator Agents; D000241:Adenosine
keywords: Doppler-derived flow velocity; coronary flow measurements; dose-response curve; fractional flow reserve; hyperemia; intracoronary adenosine