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 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 x 106 dyn/cm2 (95% confidence interval (CI) 0.14 to 0.21 x 106 dyn/cm2) compared with a reduction of 0.07 x 106 dyn/cm2 (95% CI 0.05 to 0.10 x 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.