Comparative study on calcium channel antagonists in the human radial artery: Clinical implications

Authors
Citation
Gw. He et Cq. Yang, Comparative study on calcium channel antagonists in the human radial artery: Clinical implications, J THOR SURG, 119(1), 2000, pp. 94-100
Citations number
21
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Journal title
JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY
ISSN journal
00225223 → ACNP
Volume
119
Issue
1
Year of publication
2000
Pages
94 - 100
Database
ISI
SICI code
0022-5223(200001)119:1<94:CSOCCA>2.0.ZU;2-I
Abstract
Objectives: The radial artery is spastic, and calcium channel antagonists h ave been used clinically in the radial artery for their antispastic effects . To choose a proper calcium channel antagonist for such a purpose, we comp ared the in vitro antispastic effects of 4 clinically used calcium channel antagonists (nicardipine, nifedipine, verapamil, and diltiazem) in the huma n radial artery. Methods: Radial artery segments taken from patients underg oing coronary bypass operations were studied in the organ bath. The relaxat ion by the calcium channel antagonists was compared in the potassium-precon tracted (25 mmol/L) radial artery. The inhibitory effect of the calcium cha nnel antagonists at the clinically relevant plasma concentration and a high er concentration was also studied for the calcium channel antagonists. Resu lts: All calcium channel antagonists induced a full relaxation (97.8%-100%, n = 5-7 for each), with higher sensitivity (P =.005, analysis of variance [ANOVA] among the calcium channel antagonists for the effective concentrati on of the constrictor [or dilator] agent that caused 50% of maximal contrac tion [or relaxation]) to nifedipine (-7.37 +/- 0.20 log(10) M) than nicardi pine (-6.43 +/- 0.39 log(10) M, P =.1), verapamil(-6.08 +/- 0.13 log(10) M, P =.03), and diltiazem (-5.87 +/- 0.07 log(10) M, P =.01). Pretreatment wi th the plasma concentration of the calcium channel antagonists (60 nmol/L f or diltiazem and 20 nmol/L for the others) inhibited the potassium-induced contraction (n = 6 for each) by nicardipine (from 138.6% +/- 5.8% to 101.4% +/- 7.6%, P =.001) and nifedipine (to 87.7% +/- 6.8%, P =.0003) but not by verapamil (to 140.3% +/- 15.2%, P =.9) or diltiazem (to 132.8% +/- 7.3%, P =.8), although at higher contractions (-4.5 log(10) M) all 4 calcium chann el antagonists abolished the contraction. Conclusions: Although all calcium channel antagonists have antispastic effects in the radial artery, the ves sel has different sensitivities to them. Dihydropyridine derivatives may be the most potent calcium channel antiagonists and therefore are recommended for the clinical use for this purpose.