title: A comparative study on in vitro and in vivo effects of topical vasodilators in human internal mammary, radial artery and great saphenous vein.
abstract: OBJECTIVE
  As an important prognostic factor of coronary artery bypass grafting (CABG), graft vasospasm can be observed in all currently used graft conduits. Radial artery (RA) vasospasm is more prone to occur in comparisons with internal mammary artery (IMA) and great saphenous vein (GSV). There is still controversy about which antispasmodic agent is superior to different grafts, especially to RA conduits. The aim of this pilot study was to investigate the relaxation response of four topical vasodilators to different in vitro grafts and how these vasodilators affect the blood flow of the vessel in situ during RA harvesting.
  
  
  METHODS
  Vasodilatory properties of diltiazem, nitroglycerin, urapidil and nicorandil were compared in matched patient-specific segments of RA, IMA and GSV harvested from 12 patients. The vasodilatory response of the RA to intraradial administration of nitroglycerin, diltiazem and urapidil was compared in vivo (n=10 per group) by assessing the free blood flow of RA.
  
  
  RESULTS
  (1) The maximal relaxations occurring with urapidil, nitroglycerin and nicorandil in IMA, RA and SGV were significantly greater than that with diltiazem. The reactivity of all three graft conduits showed similar relaxation with nitroglycerin or with diltiazem, but the relaxation with urapidil in RA showed greater than that of IMA and GSV, and RA and GSV showed greater relaxation with nicorandil than IMA. (2) A dose of 10(-5)mol/l of nitroglycerin, urapidil and nicorandil but not diltiazem significantly inhibited the RA response to PE. (3) In vivo, urapidil and nitroglycerin significantly increased the RA blood flow, the potency of which was greater than that caused by diltiazem.
  
  
  CONCLUSIONS
  (1) Comparing with nicorandil, urapidil and diltiazem, nitroglycerin caused a significant relaxation in all three graft vessels tested. (2) Nitroglycerin, nicorandil and urapidil were more effective in preventing RA spasm than diltiazem.
authors.affiliation: Heart Center of Beijing Friendship Hospital Affiliated Capital University of Medical Science, China.
authors.forename: Rongjing
authors.initials: R
authors.lastname: Ding
authors.forename: Wenhui
authors.initials: W
authors.lastname: Feng
authors.forename: Hongwei
authors.initials: H
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Dalian
authors.initials: D
authors.lastname: Li
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Cheng
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Guo
authors.forename: Dayi
authors.initials: D
authors.lastname: Hu
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D004110:Diltiazem / Q000494:pharmacology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008323:Mammary Arteries / Q000187:drug effects* / Q000502:physiology; D008875:Middle Aged; D020108:Nicorandil / Q000494:pharmacology; D005996:Nitroglycerin / Q000494:pharmacology; D009924:Organ Culture Techniques; D010879:Piperazines / Q000494:pharmacology; D017534:Radial Artery / Q000187:drug effects* / Q000502:physiology; D012501:Saphenous Vein / Q000187:drug effects* / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D010879:Piperazines; D014665:Vasodilator Agents; D020108:Nicorandil; C015568:urapidil; D004110:Diltiazem; D005996:Nitroglycerin