title: In vivo functional flowmetric behavior of the radial artery graft: is the composite Y-graft configuration advantageous over conventional aorta-coronary bypass?
abstract: BACKGROUND
  Intraoperative flowmetric results of different configurations (Y-graft or aorta-coronary) of radial artery grafts have been poorly investigated.
  
  
  METHODS
  We report the results of an observational study designed to analyze transit-time flow measurements at baseline and during 1:1 intra-aortic balloon pumping in 114 consecutive patients receiving the radial artery as a aorta-coronary bypass (group A, 72 patients) or as a Y-graft with the left internal thoracic artery (group B, 42 patients). Graft flow reserve, recruited by 1:1 intra-aortic balloon pumping) greater than 1 indicated recruitment of surplus graft flow. Results were stratified by grafted territory and surgical technique.
  
  
  RESULTS
  Hospital outcome was comparable. Baseline transit-time flow results were similar between the 2 groups in terms of maximum diastolic flow, minimum systolic flow, mean flow, and pulsatility index. Graft flow reserve was not recruited by intra-aortic balloon pumping in 3 (2.7%) malfunctioning single aorta-oronary radial artery bypass grafts (P = .005 versus successful radial artery bypass grafts). Graft flow reserve was recruited (>1) by intra-aortic balloon pumping in the remaining 111 patent radial artery bypass grafts. Y-grafts showed higher maximum diastolic flow P < .0001), mean flow (P < .0001), graft flow reserve (P < .0001), percentage improvement of maximum diastolic flow (P < .0001), and of mean flow (P < .0001) compared with aorta-coronary radial artery bypass grafts. These results were confirmed for the right coronary (P < or = .004) and the circumflex territory (P < or = .001), for off-pump (P < or = .008) or cardiopulmonary bypass (P < .0001) and for patients undergoing isolated bypass grafting (P < .0001).
  
  
  CONCLUSIONS
  Intraoperative flows of radial artery bypass grafts showed comparable baseline results in single aorta-coronary conduits and Y-grafts. Graft flow reserve recruited by intra-aortic balloon pumping was higher in Y-conduits, regardless of the grafted territory and the perfusion strategy chosen. Failed radial artery bypass grafts did not improve transit-time flow results during 1:1 intra-aortic balloong pumping nor showed any recruitment of graft flow reserve.
authors.affiliation: Cardiac Surgery Unit, Magna Graecia University of Catanzaro, Catanzaro, Italy. frankono@libero.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Onorati
authors.forename: Antonino Salvatore
authors.initials: AS
authors.lastname: Rubino
authors.forename: Lucia
authors.initials: L
authors.lastname: Cristodoro
authors.forename: Cristian
authors.initials: C
authors.lastname: Scalas
authors.forename: Sergio
authors.initials: S
authors.lastname: Nucera
authors.forename: Francesco
authors.initials: F
authors.lastname: Santini
authors.forename: Attilio
authors.initials: A
authors.lastname: Renzulli
mesh_terms: D001783:Blood Flow Velocity; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D047549:Coronary Artery Bypass, Off-Pump; D003324:Coronary Artery Disease / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D003326:Coronary Circulation; D017052:Hospital Mortality; D006801:Humans; D007423:Intra-Aortic Balloon Pumping; D011446:Prospective Studies; D017534:Radial Artery / Q000503:physiopathology / Q000637:transplantation*; D012039:Regional Blood Flow; D056346:Sternotomy; D016896:Treatment Outcome