title: Comparison of flow characteristics and vascular reactivity of radial artery and long saphenous vein grafts [NCT00139399].
abstract: BACKGROUND
  The morphological and functional differences between arteries and veins may have implications on coronary artery bypass graft (CABG) survival. Although subjective differences have been observed between radial artery (RA) and long saphenous venous (LSV) grafts, these have not been quantified. This study assessed and compared the flow characteristics and in-vivo graft flow responses of RA and LSV aorto-coronary grafts.
  
  
  METHODS
  Angiograms from 52 males taken 3.7 +/- 1.0 months after CABG surgery were analyzed using adjusted Thrombolysis in Myocardial Infarction (TIMI) frame count. Graft and target coronary artery dimensions were measured using quantitative coronary angiography. Estimated TIMI velocity (V(E)) and volume flow (F(E)) were then calculated. A further 7 patients underwent in-vivo graft flow responses assessments to adenosine, acetylcholine and isosorbide dinitrate (ISDN) using intravascular Doppler.
  
  
  RESULTS
  The V(E) for RA grafts was significantly greater than LSV grafts (P = 0.002), however there was no difference in volume F(E) (P = 0.20). RA grafts showed positive endothelium-dependent and -independent vasodilatation, and LSV grafts showed no statistically significant response to adenosine and acetylcholine. There was no difference in flow velocity or volume responses. Seven RA grafts (11%) had compromised patency (4 (6%) > or = 50% stenosis in the proximal/distal anastomoses, and 3 (5%) diffuse narrowing). Thirty-seven (95%) LSV grafts achieved perfect patency and 2 (5%) were occluded.
  
  
  CONCLUSIONS
  The flow characteristics and flow responses of the RA graft suggest that it is a more physiological conduit than the LSV graft. The clinical relevance of the balance between imperfect patency versus the more physiological vascular function in the RA graft may be revealed by the 5-year angiographic follow-up of this trial.
authors.affiliation: Department of Cardiothoracic Surgery, Royal Brompton and Harefield NHS Trust, London, UK. chong_chee_fui@hotmail.com
authors.forename: William C F
authors.initials: WC
authors.lastname: Chong
authors.forename: Peter
authors.initials: P
authors.lastname: Collins
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Webb
authors.forename: Anthony C
authors.initials: AC
authors.lastname: De Souza
authors.forename: John R
authors.initials: JR
authors.lastname: Pepper
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Hayward
authors.forename: Neil E
authors.initials: NE
authors.lastname: Moat
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology; D001783:Blood Flow Velocity; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000379:methods*; D003331:Coronary Vessels / Q000502:physiology / Q000601:surgery; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D006085:Graft Survival; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007548:Isosorbide Dinitrate / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D017534:Radial Artery / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology / Q000637:transplantation*; D012039:Regional Blood Flow; D012501:Saphenous Vein / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology / Q000637:transplantation*; D016896:Treatment Outcome; D014654:Vascular Patency; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D007548:Isosorbide Dinitrate; D000241:Adenosine; D000109:Acetylcholine