Comparative haemodynamic effects of nicardipine and verapamil in coronary artery disease

Abstract

The haemodynamic relevance of the disparate electrophysiological and structural differences between agents blocking the slow-calcium channels in patients with exercise-induced angina pectoris is controversial. We therefore evaluated the effects of single intravenous and equivalent hypotensive doses of nicardipine (7.5 mg) or verapamil (16 mg) in a randomized single-blind study of 30 patients with angiographically documented coronary artery disease. The randomization process achieved comparable distribution of 15 patients with similar demographic data and cardiac function to each drug. Patients were evaluated at rest and during four minutes upright bicycle exercise at an individually titrated symptom-limited load in both control and post-drug assessments; the reproducibility of the haemodynamics during such tests has been previously demonstrated. Both nicardipine and verapamil induced similar reductions in systemic mean arterial blood pressure and vascular resistance; the reduction in afterload resulted in increased resting cardiac index and stroke volume index on each agent. The magnitude of the former increase was greater following nicardipine (p less than 0.05). The pulmonary artery occluded pressure (PAOP) increased following verapamil (p less than 0.01) without change following nicardipine. During dynamic exercise, neither drug improved cardiac stroke volume index, the PAOP was significantly higher following verapamil compared with nicardipine (p less than 0.05). Analysis of the cardiac performance curve demonstrated its significant depression following verapamil but not following nicardipine. Thus clear haemodynamic advantages were present, both at rest and during exercise-induced angina, for nicardipine; whether such haemodynamic effects will be reflected in symptomatic terms should be critically evaluated.