title: Comparable prognostic value of vasodilator response to acetylcholine in brachial and coronary arteries for predicting long-term cardiovascular events in suspected coronary artery disease.
abstract: BACKGROUND
  Vasodilator response to acetylcholine (ACh) (ie, endothelium-dependent dilation) is impaired in the peripheral and coronary circulation of patients with coronary risk factors and coronary artery disease (CAD). There is a close relationship of vasodilator response to ACh in both the coronary artery (CA) and the brachial artery (BA), but the comparative prognostic importance of these responses has not been fully investigated in relatively low-risk suspected CAD.
  
  
  RESULTS
  The flow responses of both the CA and BA were measured in 70 patients with suspected CAD, excluding patients with triple-vessel disease and known peripheral or cerebrovascular disorders. A Doppler guidewire was placed into a major branch of the CA and a proximal portion of the left BA. ACh was infused at 10(-8), 10(-7) and 10(-6) mol/L for 3 min into the CA and at 7.5, 15, and 30 mug/min for 5 min into BA. The flow response was obtained by multiplying the average peak velocity by the cross-sectional area from quantitative angiography. Vasodilator response to ACh was assessed by the ratio of ACh-induced flow/baseline flow, expressed as coronary blood flow index (CBFI) or brachial blood flow index (BBFI). There were 39 CAD patients (61 +/- 8 years old) and 31 normal coronary patients (NL, 58 +/- 11 years old) who were followed up for 53 +/- 17 months. Eleven patients had coronary events (CE) during this period: 1 case of nonfatal myocardial infarction and 10 cases of unstable angina. A strong correlation between CBFI and BBFI was observed at middle-and high-doses of ACh (r=0.72, p<0.0001, 15 microg/min vs 10(-7) mol/L; r=0.76, p<0.0001, 30 microg/min vs 10(-6) mol/L). Kaplan-Meier analysis, using the best cut-off values obtained from receiver-operating characteristic curves for CE, revealed that both CBFI and CAFI were significant predictors for CE.
  
  
  CONCLUSIONS
  The BA vasodilator response to optimal ACh dosage can be used as a surrogate prognostic predictor for coronary endothelial function tests in patients with suspected CAD.
authors.affiliation: National Defense Medical College Research Institute, Division of Biomedical Engineering and Internal Medicine-1, Tokorozawa, Saitama, Japan. dui1577@db3.so-net.ne.jp
authors.forename: Bonpei
authors.initials: B
authors.lastname: Takase
authors.forename: Akira
authors.initials: A
authors.lastname: Hamabe
authors.forename: Kimio
authors.initials: K
authors.lastname: Satomura
authors.forename: Takasi
authors.initials: T
authors.lastname: Akima
authors.forename: Akimi
authors.initials: A
authors.lastname: Uehata
authors.forename: Takemi
authors.initials: T
authors.lastname: Matsui
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Ohsuzu
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ishihara
authors.forename: Akira
authors.initials: A
authors.lastname: Kurita
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000368:Aged; D001783:Blood Flow Velocity / Q000187:drug effects; D001916:Brachial Artery / Q000187:drug effects / Q000503:physiopathology*; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000503:physiopathology*; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D003327:Coronary Disease / Q000503:physiopathology*; D003331:Coronary Vessels / Q000187:drug effects / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000503:physiopathology*; D011379:Prognosis; D012307:Risk Factors; D012907:Smoking; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
chemical_list: D000109:Acetylcholine