title: Endothelium-dependent and endothelium-independent vasodilator response of left and right internal mammary and internal thoracic arteries used as a composite Y-graft.
abstract: OBJECTIVE
  The manner in which a blood vessel is for used as a coronary graft may be important in maintaining a viable and functional endothelial lining. Composite internal thoracic arteries (ITAs) in a Y-graft configuration are characterized by the connection of an in situ left ITA with preserved innervation and lymphatics and of a free semi-skeletonized right ITA.
  
  
  METHODS
  To determine whether endothelial function differs between left and right ITA segments in a Y-graft configuration, 11 patients were studied 3 years after surgery. The endothelium-dependent vasodilator substance P was selectively infused (1.4-22.4 pmol min⁻¹ in doubling dose increments) in the ostium of ITA Y-grafts. A maximal endothelium-independent vasodilatory response was then obtained by intragraft infusion of 2mg isosorbide dinitrate (ISDN). Biplane angiograms obtained at 3-min intervals using an automated contrast injection system with fixed preset volume and pressure parameters were analyzed off-line using a quantitative analysis system (CAAS, Pie Medical).
  
  
  RESULTS
  A similar dose-dependent vasodilatory response to substance P was observed in the left and in the right ITA. No difference in maximal endothelium-dependent response to substance P (7.4 ± 4.3% in the left ITA and 8.1 ± 5.3% in the right ITA) or in maximal endothelium-independent response to ISDN (12.2 ± 4.4% in the left ITA and 10.6 ± 8.1% in the right ITA) was observed.
  
  
  CONCLUSIONS
  The endothelium-dependent and the endothelium-independent vasodilator capacity of the two branches of a Y-graft ITA configuration appear similar 3 years after bypass surgery. This suggests that the preservation of the ITA pedicle does not significantly affect basal vasomotor tone, long-term endothelial function, or vasodilator reserve.
authors.affiliation: Department of Cardiovascular Medicine and Surgery of the Université Catholique de Louvain Medical School, Brussels, Belgium. david.glineur@uclouvain.be
authors.forename: David
authors.initials: D
authors.lastname: Glineur
authors.forename: Sophia
authors.initials: S
authors.lastname: Djaoudi
authors.forename: William
authors.initials: W
authors.lastname: D'horre
authors.forename: Olivier
authors.initials: O
authors.lastname: Gurne
authors.forename: Astrid
authors.initials: A
authors.lastname: Delouvroy
authors.forename: Laurent
authors.initials: L
authors.lastname: de Kerchove
authors.forename: Gebrine
authors.initials: G
authors.lastname: El Khoury
authors.forename: Claude
authors.initials: C
authors.lastname: Hanet
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000601:surgery*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004730:Endothelium, Vascular / Q000503:physiopathology*; D045462:Endothelium-Dependent Relaxing Factors / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007387:Internal Mammary-Coronary Artery Anastomosis; D007548:Isosorbide Dinitrate; D008297:Male; D008323:Mammary Arteries / Q000503:physiopathology*; D008875:Middle Aged; D011184:Postoperative Period; D013373:Substance P / Q000008:administration & dosage; D014664:Vasodilation / Q000502:physiology*; D014665:Vasodilator Agents
chemical_list: D045462:Endothelium-Dependent Relaxing Factors; D014665:Vasodilator Agents; D013373:Substance P; D007548:Isosorbide Dinitrate