title: The effects of intravascular stents on vasomotion in porcine coronary arteries.
abstract: Intravascular stents are being increasingly utilized in the treatment of atherosclerotic coronary artery disease, however little is known about the effects of stents on coronary vasomotion. The purpose of the present study was to compare the effects of a heparin treated tantalum stent and balloon injury on coronary artery vasorelaxation and vasoconstriction. Male miniswine underwent cardiac catheterization and oversized balloon injury to the right and left circumflex coronary arteries. After two weeks, one artery was either balloon-injured again, or underwent implantation of a stent. Four weeks later, the coronary arteries were prepared for in vitro isometric ring studies. Vasodilator responses to bradykinin and A23187 calcium ionophore were significantly impaired in balloon-injured vessels. The bradykinin and A23187 responses in stented vessels showed significantly less vasorelaxation, compared to both balloon-injured and normal vessels. There were no significant differences between any of the groups in their vasodilator response to nitroprusside. Vasoconstrictor responses to acetylcholine were significantly greater in balloon-injured vessels, compared to normal vessels. Stented vessels, however, showed markedly less vasoconstriction to acetylcholine compared to both balloon-injured and normal vessels. The maximal KCI vasoconstrictor responses in balloon injured vessels and normal controls were not significantly different. However, the maximal KCI responses in stented vessels showed significantly less constriction compared to both balloon injured and normal vessels. In conclusion, the data demonstrated that coronary arteries implanted with a heparin treated tantalum stent were capable of vasomotor activity. Both conventional balloon angioplasty and stents resulted in impaired endothelium-dependent vasorelaxation. Endothelium-independent vasorelaxation, however, was not impaired.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Dalton Cardiovascular Research Center, Department of Veterinary Biomedical Sciences, University of Missouri, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Jenkins
authors.forename: R
authors.initials: R
authors.lastname: Webel
authors.forename: M H
authors.initials: MH
authors.lastname: Laughlin
authors.forename: S M
authors.initials: SM
authors.lastname: Rowland
authors.forename: M F
authors.initials: MF
authors.lastname: Yoklavich
authors.forename: K
authors.initials: K
authors.lastname: Branson
authors.forename: J L
authors.initials: JL
authors.lastname: Parker
authors.forename: P R
authors.initials: PR
authors.lastname: Myers
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D000818:Animals; D000925:Anticoagulants; D003331:Coronary Vessels / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000503:physiopathology; D006493:Heparin; D006937:Hypercholesterolemia / Q000503:physiopathology; D008297:Male; D015607:Stents; D013552:Swine; D013556:Swine, Miniature; D013635:Tantalum; D014661:Vasoconstriction / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology