title: Flow-mediated vasodilation during pacing of the free epigastric artery bypass graft early and late postoperatively.
abstract: OBJECTIVE
  The free epigastric artery bypass graft is proposed as an alternative conduit to the saphenous vein graft, known for its high rate of attrition. The aim of our study was to assess its endothelial function in vivo.
  
  
  BACKGROUND
  The endothelium of arterial bypass grafts plays a role in both the performance and the patency of such grafts.
  
  
  METHODS
  We studied 73 epigastric grafts early (mean +/- SD 10 +/- 3 days) and 36 late (12 +/- 5 months) after coronary bypass surgery with quantitative angiography at rest, after 2 min of atrial pacing (130 beats/min) and after injection of isosorbide dinitrate (1 to 2 mg) into the graft.
  
  
  RESULTS
  At rest, mean epigastric graft diameter was lower in the late than in the early postoperative period (2.26 +/- 0.39 vs. 2.61 +/- 0.49 mm, p < 0.001). Early after operation, epigastric grafts with a small or an intermediate runoff, but not those with a large runoff, were capable of vasodilation with nitrates (+0.09 +/- 0.10 mm). Late after operation, vasodilation after administration of isosorbide dinitrate was similar in epigastric grafts with a large runoff and in those with a small or intermediate runoff (+ 0.23 +/- 0.09 vs. +0.23 +/- 0.18 mm). Significant vasodilation during pacing was observed late (+4 +/- 9%, p < 0.01) but not early postoperatively, except in a subset of patients with grafts capable of vasodilation after nitrates. A correlation between the response to nitrates and the response during pacing was observed early (r = 0.579, p < 0.001) and late postoperatively (r = 0.530, p = 0.02).
  
  
  CONCLUSIONS
  Flow-mediated vasodilation during pacing was observed in most epigastric grafts late, but not early, after operation. This endothelium-dependent dilation was correlated with the importance of the vasodilation observed with nitrates (endothelium-independent), which was related to the importance of the runoff only in the early postoperative period. The ability of epigastric grafts late postoperatively to dynamically adapt their dimensions to an acute increase in demand could contribute to the good functional results of this new alternative arterial graft.
authors.affiliation: Department of Cardiology, University of Louvain, Mont-Godinne Hospital, Yvoir, Belgium.
authors.forename: O
authors.initials: O
authors.lastname: Gurné
authors.forename: P
authors.initials: P
authors.lastname: Chenu
authors.forename: M
authors.initials: M
authors.lastname: Buche
authors.forename: J
authors.initials: J
authors.lastname: Jamart
authors.forename: Y
authors.initials: Y
authors.lastname: Louagie
authors.forename: P
authors.initials: P
authors.lastname: Eucher
authors.forename: B
authors.initials: B
authors.lastname: Marchandise
authors.forename: E
authors.initials: E
authors.lastname: Schroeder
mesh_terms: D006328:Cardiac Catheterization; D002304:Cardiac Pacing, Artificial; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000379:methods*; D003326:Coronary Circulation / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D019074:Epigastric Arteries / Q000502:physiology* / Q000637:transplantation*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007548:Isosorbide Dinitrate; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D013997:Time Factors; D014654:Vascular Patency / Q000502:physiology; D014664:Vasodilation / Q000502:physiology*; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D007548:Isosorbide Dinitrate