title: Intraindividual comparison of human radial and internal thoracic arteries in vitro and the effect of preoperative calcium blocker therapy.
abstract: The patency rate of radial artery (RA) conduits is considerably lower than that of internal thoracic artery (ITA) grafts and the evidence suggests that this is due to a clinically suspected higher incidence of vasospasm. The aim of this study was, therefore, to compare intraindividually the pharmacological reactivity of RA with that of ITA. Both RA and ITA were taken from the same patients and investigated in parallel. Changes in tone were monitored isometrically on ring preparations from both arteries in organ baths with modified Krebs-Henseleit solution containing 1.25 mm calcium chloride at 1 g passive preload. In intraindividual comparisons maximal receptor-mediated contractile responses to noradrenaline and endothelin-1 and endothelium-dependent acetylcholine-induced relaxant responses revealed no differences between both arteries. By contrast, depolarization-induced contractions to potassium chloride (KCl) appeared to be significantly higher in RA than in ITA. Further analysis, however, revealed that this difference was due to preoperative calcium entry blocker (Ca(2+)eB) therapy. Compared with control tissues, maximal responses to KCl were significantly attenuated in the ITA but unchanged in RA when arteries were obtained from patients with preoperative Ca(2+)eB therapy. The present results suggested that functional responses to pharmacological stimuli of both RA and ITA were quite similar. Preoperative Ca(2+)eB therapy, however, attenuated markedly responses to KCl of the ITA leaving those of RA unchanged. These results, demonstrating a lower sensitivity to Ca(2+)eB of RA, therefore suggested that in addition to Ca(2+)eB other classes of drug may be more effective at reducing the propensity of RA conduits to vasospasm.
authors.affiliation: Division of Cardiothoracic Surgery, University Hospital, Spitalstrasse 21, CH-4031 Basel, Switzerland.
authors.forename: Martin T R
authors.initials: MT
authors.lastname: Grapow
authors.forename: David C
authors.initials: DC
authors.lastname: Reineke
authors.forename: Thomas
authors.initials: T
authors.lastname: Kern
authors.forename: Carlo
authors.initials: C
authors.lastname: Antona
authors.forename: Guido
authors.initials: G
authors.lastname: Gelpi
authors.forename: Eduardo
authors.initials: E
authors.lastname: Santoli
authors.forename: Hans-Reinhard
authors.initials: HR
authors.lastname: Zerkowski
authors.forename: Thierry P
authors.initials: TP
authors.lastname: Carrel
authors.forename: Else
authors.initials: E
authors.lastname: Müller-Schweinitzer
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000368:Aged; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology; D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D019332:Endothelin-1 / Q000494:pharmacology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008323:Mammary Arteries / Q000187:drug effects* / Q000502:physiology; D008875:Middle Aged; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology*; D011300:Preoperative Care; D017534:Radial Artery / Q000187:drug effects* / Q000502:physiology; D044022:Receptor, Endothelin A / Q000502:physiology; D044023:Receptor, Endothelin B / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D000317:Adrenergic alpha-Antagonists; D002121:Calcium Channel Blockers; D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D019332:Endothelin-1; D009842:Oligopeptides; D010456:Peptides, Cyclic; D010880:Piperidines; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D014662:Vasoconstrictor Agents; C086539:BQ 788; D011189:Potassium Chloride; D002122:Calcium Chloride; C072247:cyclo(Trp-Asp-Pro-Val-Leu); D009638:Norepinephrine; D010646:Phentolamine