title: Balancing the benefits and risks of blood transfusions in patients undergoing cardiac surgery: a propensity-matched analysis.
abstract: OBJECTIVE
  Prior studies have found that cardiac surgery patients receiving blood transfusions are at risk for increased mortality and morbidity following surgery. It is not clear whether this increased risk occurs across all haematocrit (HCT) levels. The goal of this study was to compare operative mortality in propensity-matched cardiac surgery patients based on stratification of the preoperative HCT levels.
  
  
  METHODS
  Between 1 August 2004 and 30 June 2011, 3516 patients had cardiac surgery. One thousand nine hundred and twenty-two (54.5%) required blood transfusion during or after surgery. A propensity score for transfusion was developed based on 22 baseline variables. One thousand seven hundred and fourteen patients were matched: 857 in the transfusion group (TG) and 857 in the non-transfused control group (CG). Univariate analyses demonstrated that, after propensity matching, the groups did not differ on any baseline factors included in the propensity model. Operative mortality was defined as death within 30 days of surgery. Preoperative HCT was stratified into four groups: <36, 36-39, 40-42 and ≥ 43.
  
  
  RESULTS
  For HCT <36%, 30-day mortality was higher in the TG than that in the CG (3.0 vs 0.0%). For HCT 36-39, operative mortality was similar between TG (1.1%, N = 180) and CG (0.8%, N = 361; P = 0.748). For HCT 40-42, operative mortality was significantly higher in the TG compared with that in the CG (1.9 vs 0%, N = 108 and 218, respectively; P = 0.044). For HCT of ≥ 43, there was a trend towards higher operative mortality in the TG vs the CG (2.0 vs 0%, N = 102 and 152, respectively; P = 0.083). Other surgical complications followed the same pattern with higher rates found in the transfused group at higher presurgery HCT levels. HCT at discharge for the eight groups were similar, with an average of 29.1 ± 1.1% (P = 0.117).
  
  
  CONCLUSIONS
  Our study indicates that a broad application of blood products shows no discernible benefits. Furthermore, patients who receive blood at all HCT levels may be placed at an increased risk of operative mortality and/or other surgical complications. Paradoxically, even though patients with low HCTs theoretically should benefit the most, transfusion was still associated with a higher complication and mortality rate in these patients. Our results indicate that blood transfusion should be used judiciously in cardiac surgery patients.
authors.affiliation: Valley Columbia Heart Center, Columbia University College of Physicians and Surgeons, Ridgewood, NJ 07450, USA.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Shaw
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Johnson
authors.forename: Giovanni
authors.initials: G
authors.lastname: Ferrari
authors.forename: Alex
authors.initials: A
authors.lastname: Zapolanski
authors.forename: Mariano
authors.initials: M
authors.lastname: Brizzio
authors.forename: Nancy
authors.initials: N
authors.lastname: Rioux
authors.forename: Srinivasa
authors.initials: S
authors.lastname: Edara
authors.forename: Jason
authors.initials: J
authors.lastname: Sperling
authors.forename: Juan B
authors.initials: JB
authors.lastname: Grau
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D016063:Blood Loss, Surgical / Q000401:mortality / Q000517:prevention & control*; D001803:Blood Transfusion / Q000401:mortality; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000401:mortality; D016009:Chi-Square Distribution; D005260:Female; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018579:Patient Selection; D019106:Postoperative Hemorrhage / Q000097:blood / Q000209:etiology / Q000401:mortality / Q000628:therapy*; D057216:Propensity Score; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D065227:Transfusion Reaction; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D006454:Hemoglobins
keywords: 30-day mortality; Blood transfusion; Haematocrit; Postoperative anaemia
references.citation: Transfusion. 2013 Apr;53(4):790-7
references.pmid: 22882381
references.citation: Intensive Care Med. 2011 Jan;37(1):97-109
references.pmid: 20721533
references.citation: Ann Thorac Surg. 2011 Mar;91(3):944-82
references.pmid: 21353044
references.citation: Ann Thorac Surg. 2012 Aug;94(2):460-7
references.pmid: 22626751
references.citation: Anesth Analg. 1995 May;80(5):910-6
references.pmid: 7726433
references.citation: Ann Thorac Surg. 2012 Dec;94(6):2038-45
references.pmid: 22959580
references.citation: Anesth Analg. 2010 Nov;111(5):1088-92
references.pmid: 20971958
references.citation: Semin Cardiothorac Vasc Anesth. 2005 Mar;9(1):53-63
references.pmid: 15735844
references.citation: Circulation. 2006 Jul 4;114(1 Suppl):I43-8
references.pmid: 16820613
references.citation: JAMA. 2010 Oct 13;304(14):1568-75
references.pmid: 20940382
references.citation: N Engl J Med. 1999 Feb 11;340(6):409-17
references.pmid: 9971864
references.citation: Br J Anaesth. 2011 Dec;107 Suppl 1:i41-59
references.pmid: 22156270
references.citation: Transfus Med Rev. 2011 Jul;25(3):232-246.e53
references.pmid: 21498040
references.citation: Ann Thorac Surg. 2001 Mar;71(3):769-76
references.pmid: 11269449
references.citation: J Cardiothorac Vasc Anesth. 2010 Oct;24(5):814-6
references.pmid: 20709572
references.citation: Transfusion. 2013 Jan;53(1):19-27
references.pmid: 22574710
references.citation: South Med J. 2011 Nov;104(11):762-9
references.pmid: 22024787
references.citation: Semin Thorac Cardiovasc Surg. 2010 Summer;22(2):121-6
references.pmid: 21092889
references.citation: Ann Thorac Surg. 2010 Aug;90(2):451-8
references.pmid: 20667328
references.citation: Circulation. 1997 Nov 4;96(9 Suppl):II-194-9
references.pmid: 9386097
references.citation: Crit Care. 2009;13 Suppl 5:S11
references.pmid: 19951383
references.citation: Am J Cardiol. 2006 Nov 1;98(9):1223-5
references.pmid: 17056333
references.citation: Anesthesiology. 1998 Feb;88(2):327-33
references.pmid: 9477051
references.citation: Anesth Analg. 2009 Jun;108(6):1741-6
references.pmid: 19448195
references.citation: Ann Thorac Surg. 2007 May;83(5 Suppl):S27-86
references.pmid: 17462454