Differential effects of calcium channel antagonists in the amelioration of radial artery vasospasm.
Ann Thorac Surg
; 69(4): 1035-40; discussion 1040-1, 2000 Apr.
Article
en En
| MEDLINE
| ID: mdl-10800790
ABSTRACT
BACKGROUND:
Radial artery (RA) is being used for coronary artery bypass grafting (CABG) with greater frequency. However, RA is prone to post-CABG vasospasm, which may be neurohormonally mediated. Use of the calcium channel antagonist diltiazem has been advocated as a strategy to reduce post-CABG RA vasospasm. However, whether and to what degree different calcium channel antagonists influence neurohormonally induced RA vasoconstriction remains unknown.METHODS:
RA segments were collected from patients undergoing elective CABG (n = 13), and isometric tension was examined in the presence of endothelin (10 nM) or norepinephrine (1 microM). In matched RA, endothelin- or norepinephrine-induced contractions were measured in the presence of diltiazem (277 nM), amlodipine (73 nM), or nifedipine (145 nM). These concentrations of calcium channel antagonists were based upon clinical plasma profiles.RESULTS:
Endothelin and norepinephrine caused a significant increase in RA-developed tension (0.54+/-0.1 and 0.68+/-0.1 g/mg, respectively; p<0.05). Amlodipine or nifedipine significantly reduced RA vasoconstriction in the presence of endothelin (30+/-6% and 41+/-9%, respectively; p<0.05) or norepinephrine (27+/-8% and 53+/-9%, respectively; p<0.05), whereas diltiazem did not significantly reduce RA vasoconstriction.CONCLUSIONS:
These results demonstrate that neurohormonal factors released post-CABG can cause RA vasoconstriction, and that calcium channel antagonists are not equally effective in abrogating that response. Both amlodipine and nifedipine, which have a higher degree of vascular selectivity, appear to be the most effective in reducing RA vasoconstriction.
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Banco de datos:
MEDLINE
Asunto principal:
Vasoconstricción
/
Bloqueadores de los Canales de Calcio
/
Diltiazem
/
Nifedipino
/
Arteria Radial
/
Amlodipino
Límite:
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Año:
2000
Tipo del documento:
Article