The comparative effects of esmolol and amiodarone on isolated coronary artery bypass grafts

Demet Özkaramanli Gür,Ozcan Gür,Selami Gürkan

doi:10.3906/sag-1802-124

Demet Özkaramanli Gür, Ozcan Gür + Show 1 more

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https://doi.org/10.3906/sag-1802-124

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Abstract

Background/aim: Esmolol and amiodarone are two most commonly used antiarrhythmic drugs in coronary artery bypass grafting (CABG) surgery. Nevertheless, blockade of beta-2 receptors by increasing doses raise concerns about possible vasospasms. We studied the vasoactive effects of amiodarone and esmolol on left internal mammary artery (LIMA), radial artery (RA), and saphenous vein (SV) grafts. Materials and methods: After determining the presence of functional smooth muscle and endothelial layers, the responses of submaximally preconstricted graft samples were recorded in a tissue bath system. A total of 96 graft samples from 40 patients were used: 16 LIMA, 16 RA, and 16 SV grafts for each drug. Esmolol and amiodarone were added to reservoirs separately, starting from a concentration of 10-8 M until a concentration of 10-4 M. Results: Although both drugs caused vasodilatation, amiodarone exhibited a more potent vasodilatory effect than esmolol (P < 0.0001 for LIMA, P = 0.0128 for RA, and P < 0.0001 for SV). The vasodilatation rates with esmolol were 48.99 ± 2.28% in LIMA, 49.77 ± 3.03% in RA, and 41.90 ± 4.05% in SV grafts and with amiodarone they were 71.65 ± 5.18% in LIMA, 58.61 ± 5.87% in RA, and 65.07 ± 4.09% in SV grafts. Conclusion: This in vitro study revealed that even increasing doses of both drugs induce vasodilatation of CABG grafts, with amiodarone having a more potent vasodilatory effect than esmolol.

Highlights

Cardiac arrhythmias are among the most common complications of coronary artery bypass grafting (CABG) surgery [1]
The vasodilatation rates with esmolol were 48.99 ± 2.28% in left internal mammary artery (LIMA), 49.77 ± 3.03% in radial artery (RA), and 41.90 ± 4.05% in saphenous vein (SV) grafts and with amiodarone they were 71.65 ± 5.18% in LIMA, 58.61 ± 5.87% in RA, and 65.07 ± 4.09% in SV grafts. This in vitro study revealed that even increasing doses of both drugs induce vasodilatation of CABG grafts, with amiodarone having a more potent vasodilatory effect than esmolol
The tissue samples from the LIMA, RA, and SV grafts obtained during CABG were placed into 4 °C Krebs solution and transported to the vascular laboratory where they were sliced into vascular rings 3 mm wide and suspended in a tissue bath system

Summary

Introduction

Cardiac arrhythmias are among the most common complications of coronary artery bypass grafting (CABG) surgery [1]. Post-CABG atrial fibrillation (AF) has an incidence rate of 15% to 50%, while the incidence rate of nonsustained ventricular tachycardia is 18% to 58% [2,3]. Esmolol and amiodarone are the two most commonly used drugs in the perioperative period for treatment of both ventricular and supraventricular arrhythmias. Esmolol is a short-acting parenteral beta-blocker and a Vaughan Williams class II antiarrhythmic. Amiodarone is a unique class III antiarrhythmic. Recent studies recommend their administration preoperatively for prophylaxis of postoperative AF, yielding more frequent utilization [4,5,6]

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