title: Randomised comparison of the effects of nicardipine and esmolol on coronary artery wall stress: implications for the risk of plaque rupture.
abstract: OBJECTIVE
  To determine whether the beta blocker esmolol reduces coronary artery wall stress more than the short acting dihydropyridine calcium antagonist nicardipine.
  
  
  METHODS
  Randomised double blind placebo controlled trial.
  
  
  METHODS
  Tertiary cardiology centre.
  
  
  METHODS
  Patients with coronary artery disease.
  
  
  METHODS
  20 patients were randomised double blind to an infusion of nicardipine (n = 10) or esmolol (n = 10) titrated to reduce systolic blood pressure by 20 mm Hg.
  
  
  METHODS
  Peak systolic wall circumferential stress.
  
  
  RESULTS
  Esmolol reduced peak coronary stress by a mean of 0.17 x 10(6) dyn/cm(2) (95% confidence interval (CI) 0.14 to 0.21 x 10(6) dyn/cm(2)) compared with a reduction of 0.07 x 10(6) dyn/cm(2) (95% CI 0.05 to 0.10 x 10(6) dyn/cm(2)) after nicardipine. Peak systolic radius was reduced by 0.04 mm (95% CI 0.03 to 0.06 mm) after esmolol compared with an increase of 0.08 mm (95% CI 0.05 to 0.10 mm) after nicardipine. Heart rate increased by 11.5 beats/min (95% CI 6.9 to 16.2 beats/min) after nicardipine and decreased by 5.3 beats/min (95% CI 1.9 to 8.6 beats/min) after esmolol.
  
  
  CONCLUSIONS
  Intravenous esmolol is more effective than nicardipine at reducing circumferential coronary artery wall stress.
authors.affiliation: Department of Medicine, University of Otago, 201 Great King Street, Dunedin, New Zealand. michael.williams@stonebow.otago.ac.nz
authors.forename: M J
authors.initials: MJ
authors.lastname: Williams
authors.forename: C J
authors.initials: CJ
authors.lastname: Low
authors.forename: G T
authors.initials: GT
authors.lastname: Wilkins
authors.forename: R A
authors.initials: RA
authors.lastname: Stewart
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000188:drug therapy*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009529:Nicardipine / Q000627:therapeutic use*; D011412:Propanolamines / Q000627:therapeutic use*; D013314:Stress, Mechanical; D018084:Ultrasonography, Interventional
chemical_list: D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers; D011412:Propanolamines; D009529:Nicardipine; C036604:esmolol