title: Blood transfusions may impair endothelium-dependent vasodilatation during coronary artery bypass surgery.
abstract: The hemolytic product free-hemoglobin (fHb) reduces nitric oxide (NO) bioavailability. The present study aims to establish whether administration of different blood transfusions result in increased circulating fHb levels and NO consumption with effects on arterial NO-dependent blood flow in patients undergoing CABG surgery.
  
  
  
  Ninety-five consecutive patients undergoing elective CABG surgery were prospectively divided in four groups based on blood transfusion requirements during surgery: stored blood cells (SBC, n. 21), intraoperative autologous salvaged blood (ASB, n. 25), SBC and ASB (n.22), no transfusion (control, n. 27). Blood samples were collected before and after intervention to analyse plasma levels of fHb and NO consumption. Endothelium-dependent relaxation was assessed in left internal mammary artery (LIMA) rings harvested before chest closure. Peripheral artery tonometry was assessed after intervention.
  
  
  
  Transfusions with SBC increased plasma fHb (p<0.05). Transfusions of ASB resulted in higher plasma fHb compared to SBC (p<0.01). fHb concentrations directly correlated with NO consumption (r=0.65, p<0.001). Maximal endothelium-dependent relaxation in LIMA was significantly attenuated in SBC and ASB patients compared to control (15.2±3.1% vs 21.1±2.5% vs 43±5.0% respectively; p<0.01). Significant correlations were identified between the aortic pressure wave velocity, plasma fHb concentration and NO consumption (p<0.01).
  
  
  
  Intraoperative blood transfusions and particularly autologous salvaged blood impair endothelium-dependent relaxation through NO scavenging by fHb. These findings obtained in vitro and in vivo provide new insights into the adverse relation between blood transfusions and patient outcome.
authors.affiliation: Department of Surgery, Division of Cardiac Surgery, University of Verona, Verona, Italy. Electronic address: alessio.rungatscher@univr.it.
authors.forename: Alessio
authors.initials: A
authors.lastname: Rungatscher
authors.affiliation: Department of Surgery, Division of Cardiac Surgery, University of Verona, Verona, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Milani
authors.affiliation: Department of Surgery, Division of Cardiac Surgery, University of Verona, Verona, Italy.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Covajes
authors.affiliation: Institute of Physiological Chemistry, Medical University of Graz, Graz, Austria. Electronic address: seth.hallstroem@medunigraz.at.
authors.forename: Seth
authors.initials: S
authors.lastname: Hallström
authors.affiliation: Department of Surgery, Division of Cardiac Surgery, University of Verona, Verona, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Gottin
authors.affiliation: Division of Clinical Biochemistry and Molecular Biology, University of Verona, Verona, Italy.
authors.forename: Gian Cesare
authors.initials: GC
authors.lastname: Guidi
authors.affiliation: Department of Surgery, Division of Cardiac Surgery, University of Verona, Verona, Italy.
authors.forename: Giovanni Battista
authors.initials: GB
authors.lastname: Luciani
authors.affiliation: Department of Surgery, Division of Cardiac Surgery, University of Verona, Verona, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Faggian
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001803:Blood Transfusion; D001804:Blood Transfusion, Autologous / Q000009:adverse effects*; D016022:Case-Control Studies; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D004730:Endothelium, Vascular / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D008323:Mammary Arteries / Q000503:physiopathology* / Q000601:surgery*; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D057725:Operative Blood Salvage; D011446:Prospective Studies; D063177:Pulse Wave Analysis; D059289:Vascular Stiffness; D014664:Vasodilation
chemical_list: D006454:Hemoglobins; D009569:Nitric Oxide
keywords: Blood transfusion; Coronary artery bypass grafting; Endothelium-dependent vasodilatation; Free hemoglobin; Nitric oxide; Peripheral artery tonometry