Randomised comparison of the effects of nicardipine and esmolol on coronary artery wall stress: implications for the risk of plaque rupture

OBJECTIVE—To determine whether the β blocker esmolol reduces coronary artery wall stress more than the short acting dihydropyridine calcium antagonist nicardipine.
DESIGN—Randomised double blind placebo controlled trial.
SETTING—Tertiary cardiology centre.
PATIENTS—Patients with coronary artery disease.
INTERVENTIONS—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.
MAIN OUTCOME MEASURES—Peak systolic wall circumferential stress.
RESULTS—Esmolol reduced peak coronary stress by a mean of 0.17 × 10⁶ dyn/cm² (95% confidence interval (CI) 0.14 to 0.21 × 10⁶ dyn/cm²) compared with a reduction of 0.07 × 10⁶ dyn/cm² (95% CI 0.05 to 0.10 × 10⁶ dyn/cm²) 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.


Keywords: β blockers; calcium channel antagonists; mechanics; coronary disease