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Haemodynamic dose-response effects of i.v. nicardipine in coronary artery disease
Insights
Nicardipine effectively reduces blood pressure and vascular resistance in patients with coronary artery disease. This calcium channel blocker improves cardiac output and stroke index at rest and during exercise.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Coronary artery disease (CAD) affects millions globally.
- Understanding the haemodynamic effects of calcium channel blockers is crucial for managing CAD.
Purpose of the Study:
- To evaluate the dose-response haemodynamic effects of nicardipine in patients with CAD.
- To assess nicardipine's impact on cardiovascular function at rest and during exercise.
Main Methods:
- 10 male patients with confirmed CAD received escalating intravenous doses of nicardipine.
- Haemodynamic variables were measured at rest and during steady-state exercise.
- Plasma nicardipine levels were correlated with haemodynamic changes.
Main Results:
- Intravenous nicardipine caused a dose-dependent decrease in systemic blood pressure and vascular resistance.
- Cardiac index and stroke index significantly increased at rest.
- During exercise, blood pressure decreased with increased cardiac output, while stroke index remained unchanged.
Conclusions:
- Nicardipine demonstrates significant dose-dependent haemodynamic effects in patients with CAD.
- The drug effectively reduces vascular resistance and improves cardiac output.
- These findings support nicardipine's potential role in managing patients with coronary artery disease.
Abstract:
The haemodynamic dose-response effects of the slow channel blocking agent nicardipine were evaluated in 10 male patients with angiographically confirmed coronary artery disease. At rest, following a similar control saline period, four doses of the drug (log cumulative dosage: 1.25, 2.5, 5.0 and 10.0 mg) were administered by i.v. infusion over a total duration of 40 min; haemodynamic variables were recorded in the 3-5 min following each 5 min infusion. During steady-state exercise the haemodynamic effects of the drug were evaluated by comparison of a control exercise period with observations made at the same workload (200-500 kpm) following the maximum cumulative dose (10 mg). Following the four i.v. infusions, the plasma nicardipine level increased log-linearly with the infused dose (r = 0.68). Compared with control measurements at rest after saline, these plasma concentrations (35 +/- 8 to 141 +/- 24 micrograms/l) resulted in a linear decrease in systemic blood pressure and vascular resistance with significant increase in cardiac index (maximum delta CI + 1.6 l min(-1) m(-2); P less than 0.01), stroke index (maximum delta SI + 11 ml/m2; P less than 0.01) and in pulmonary artery occluded pressure (maximum delta PAOP + 2 mm Hg; P less than 0.01). There was a significant increase in heart rate; the stroke work index was unchanged. During upright bicycle exercise the reduction in systemic blood pressure was accompanied by an increased exercise cardiac output without change in stroke index. The exercise pulmonary artery occluded pressure was unchanged compared with control observations, the stroke work index fell significantly (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)