Related Experiment Videos
Dose-dependent effects of intracoronary verapamil on systemic and coronary hemodynamics
O Oldenburg1, H Eggebrecht, J Herrmann
1Department of Cardiology, University of Essen, Germany. olaf.oldenburg@uni-essen.de
Insights
Intracoronary verapamil effectively increases coronary blood flow and reduces vascular resistance in a dose-dependent manner. A 1.0 mg dose maximizes these benefits, with higher doses causing a slight drop in blood pressure without further improvement.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Calcium antagonists are vital in interventional cardiology for managing coronary vasoconstriction and the no-reflow phenomenon.
- Understanding the precise hemodynamic effects of intracoronary calcium antagonists is crucial for optimizing their use.
Purpose of the Study:
- To investigate the dose-dependent impact of intracoronary verapamil on systemic and coronary hemodynamics.
- To determine the optimal dosage of intracoronary verapamil for achieving maximal coronary blood flow and minimal vascular resistance.
Main Methods:
- Twenty patients undergoing routine coronary angiography received increasing doses of intracoronary verapamil (0.01 mg to 2.0 mg) without premedication.
- Continuous monitoring of heart rate, blood pressure, and ECG, alongside intracoronary Doppler flow measurements and quantitative coronary angiography, was performed.
Main Results:
- Intracoronary verapamil significantly increased coronary blood flow (CBF) and decreased coronary vascular resistance index (CVRI) at all tested dosages.
- Systemic blood pressure decreased only at higher doses (1.0 mg and 2.0 mg), while heart rate remained unchanged.
- Maximal increase in CBF and decrease in CVRI were observed with 1.0 mg verapamil, with no further enhancement at 2.0 mg.
Conclusions:
- Intracoronary verapamil is effective in improving coronary hemodynamics, increasing CBF and reducing CVRI.
- A dosage of 1.0 mg intracoronary verapamil appears optimal for maximizing coronary vasodilatory effects.
- While higher doses may cause a slight decrease in systemic blood pressure, they do not offer additional hemodynamic benefits in the coronary circulation.
Abstract:
Calcium antagonists are used in interventional cardiology to prevent coronary vasoconstriction or to overcome the no-reflow phenomenon. The aim of the current study was to evaluate the dose-dependent effects of intracoronary verapamil on systemic and coronary hemodynamics. In 20 patients scheduled for routine coronary angiography, heart rate, blood pressure, and ECG recordings were recorded continuously and intracoronary flow velocity was obtained by intracoronary Doppler measurements in angiographically normal vessels. The cross-sectional area, measured by quantitative coronary angiography, allowed the calculation of coronary blood flow (CBF) and the coronary vascular resistance index (CVRI). Without premedication, increasing dosages of verapamil (0.01 mg, 0.1 mg, 1.0 mg, and 2.0 mg) were injected into the left coronary artery. Intracoronary verapamil administration led to a decrease in systemic blood pressure only after administration of 1.0 mg or 2.0 mg (change in mean arterial pressure: from 87.6 +/-14.6 mmHg to 80.1 +/- 14.9 mmHg and 78.5 +/- 13.9 mmHg, respectively; both P < 0.05) without a change in heart rate. Epicardial diameters of the left coronary artery increased only at dosages of 1.0 mg and 2.0 mg (from 2.14 +/- 0.4 mm to 2.22 +/- 0.3 mm, P < 0.01), whereas the coronary blood flow velocity increased significantly at the smallest dosage of 0.01 mg (from 19.9 +/- 8.7 cm/s to 33.2 +/- 14.9 cm/s, P < 0.001) and was further enhanced with increasing dosages. CBF increased and CVRI decreased at every dosage of verapamil compared with baseline values. CBF increased also after 0.1 mg (from 13.5 +/- 6.5 mL/min to 19.5 +/- 9.3 mL/min; P < 0.05), reaching a maximal effect after administration of 1.0 mg verapamil (26.3 +/- 16.1 mL/min, P < 0.05). Application of 2.0 mg did not further increase CBF compared with 1.0 mg. Intracoronary application of verapamil leads to a decrease in systemic blood pressure at higher dosages, whereas heart rate remains unchanged at any dosage. The maximal increase in coronary blood flow and decrease in vascular resistance can be reached by administration of 1.0 mg verapamil into the left coronary artery.