1. Stover PE, Siegel LC, Parks R, Levin J, Body SC, Maddi R, et al. Variability in transfusion practice for coronary artery bypass surgery persists despite national consensus guidelines: a 24-institution study. Institutions of the Multicenter Study of Perioperative Ischemia Research Group. Anesthesiology. 1998; 88: 327–333. https://doi.org/10.1097/00000542-199802000-00009 PMID: 9477051
2. Ministry of Health, Labour and Welfare in Japan. Annual survey on the use of blood products by the Min- istry of Health, Labour and Welfare in Japan. [Cited 2020 June 29]. Available from: https://www.mhlw. go.jp/stf/shingi/shingi-yakuji_127858.html. (in Japanese).
3. Paone G, Likosky DS, Brewer R, Theurer PF, Bell GF, Cogan CM, et al. Transfusion of 1 and 2 units of red blood cells is associated with increased morbidity and mortality. Ann Thorac Surg. 2014; 97: 87–93. https://doi.org/10.1016/j.athoracsur.2013.07.020 PMID: 24094521
4. Crawford TC, Magruder JT, Fraser C, Suarez-Pierre A, Alejo D, Bobbitt J, et al. Less is more: results of a statewide analysis of the impact of blood transfusion on coronary artery bypass grafting outcomes. Ann Thorac Surg. 2018; 105: 129–136. https://doi.org/10.1016/j.athoracsur.2017.06.062 PMID: 29074154
5. Koch CG, Li L, Duncan AI, Mihaljevic T, Cosgrove DM, Loop FD, et al. Morbidity and mortality risk asso- ciated with red blood cell and blood-component transfusion in isolated coronary artery bypass grafting. Cri Care Med. 2006; 34: 1608–1616. https://doi.org/10.1097/01.CCM.0000217920.48559.D8 PMID: 16607235
6. Shander A, Goobie SM, Warner MA, Aapro M, Bisbe E, Perez-Calatayud AA, et al. Essential role of patient blood management in a pandemic: a call for action. Anesth Analg. 2020; 131: 74–85.
7. World Health Organization. Maintaining a safe and adequate blood supply during the pandemic out- break of coronavirus disease (COVID-19): interim Guidance, 20 March 2020. Geneva, Switzerland, 2020. [Cited 2020 July 21]. Available from: https://apps.who.int/iris/handle/10665/331523.
8. Krieger KH, Isom OW. Blood conservation in cardiac surgery. Eds. New York, NY: Springer Science & Business Media; 2012.
9. McGill N, O’Shaughnessy D, Pickering R, Herbertson M, Gill R. Mechanical methods of reducing blood transfusion in cardiac surgery: randomised controlled trial. BMJ. 2002; 324: 1299. https://doi.org/10. 1136/bmj.324.7349.1299 PMID: 12039820
10. Balachandran S, Cross MH, Karthikeyan S, Mulpur A, Hansbro SD, Hobson P. Retrograde autologous priming of the cardiopulmonary bypass circuit reduces blood transfusion after coronary artery surgery. Ann Thorac Surg. 2002; 73: 1912–1918. https://doi.org/10.1016/s0003-4975(02)03513-0 PMID: 12078790
11. Rottman G, Ness PM. Acute normovolemic hemodilution is a legitimate alternative to allogeneic blood transfusion. Transfusion. 1998; 38: 477–480. https://doi.org/10.1046/j.1537-2995.1998.38598297218.x PMID: 9633562
12. Society of Thoracic Surgeons Blood Conservation Guideline Task Force, Ferraris VA, Brown JR, Des- potis GJ, Hammon JW, Reece TB, et al. 2011 Update to the Society of Thoracic Surgeons and the Soci- ety of Cardiovascular Anesthesiologists blood conservation clinical practice guidelines. Ann Thorac Surg. 2011; 91: 944–982. https://doi.org/10.1016/j.athoracsur.2010.11.078 PMID: 21353044
13. Zimmermann E, Zhu R, Ogami T, Lamonica A, Petrie JA 3rd, Mack C, et al. Intraoperative autologous blood donation leads to fewer transfusion in cardiac surgery. Ann Thorac Surg. 2019; 108: 1738–1744. https://doi.org/10.1016/j.athoracsur.2019.06.091 PMID: 31445910
14. Henderson RA, Mazzeffi MA, Strauss ER, Williams B, Wipfli C, Dawood M, et al. Impact of intraopera- tive high-volume autologous blood collection on allogenic transfusion during and after cardiac surgery: a propensity score matched analysis. Transfusion. 2019; 59: 2023–2029. https://doi.org/10.1111/trf. 15253 PMID: 30882929
15. Goldberg J, Paugh TA, Dickinson TA, Fuller J, Paone G, Theurer PF, et al. Greater volume of acute nor- movolemic hemodilution may aid in reducing blood transfusions after cardiac surgery. Ann Thorac Surg. 2015; 100: 1581–1587. https://doi.org/10.1016/j.athoracsur.2015.04.135 PMID: 26206721
16. Isogai T, Matsui H, Tanaka H, Fushimi K, Yasunaga H. In-hospital management and outcomes in patients with peripartum cardiomyopathy: a descriptive study using a national inpatient database in Japan. Heart Vessels. 2017; 32: 944–951. https://doi.org/10.1007/s00380-017-0958-7 PMID: 28233090
17. Isogai T, Matsui H, Tanaka H, Fushimi K, Yasunaga H. Seasonal variation in patient characteristics and in-hospital outcomes of Takotsubo syndrome: a nationwide retrospective cohort study in Japan. Heart Vessels. 2017; 32: 1271–1276. https://doi.org/10.1007/s00380-017-1007-2 PMID: 28593334
18. Austin PC. Optimal caliper widths for propensity-score matching when estimating differences in means and differences in proportions in observational studies. Pharm Stat. 2011; 10: 150–161. https://doi.org/10.1002/pst.433 PMID: 20925139
19. Salis S, Mazzanti VV, Merli G, Salvi L, Tedesco CC, Veglia F, et al. Cardiopulmonary bypass duration is an independent predictor of morbidity and mortality after cardiac surgery. J Cardiothorac Vasc Anesth. 2008; 22: 814–822. https://doi.org/10.1053/j.jvca.2008.08.004 PMID: 18948034
20. Curley GF, Shehata N, Mazer CD, Hare GMT, Friedrich JO. Transfusion triggers for guiding RBC trans- fusion for cardiovascular surgery: a systematic review and meta-analysis. Crit Care Med. 2014; 42: 2611–2624. https://doi.org/10.1097/CCM.0000000000000548 PMID: 25167086
21. Casati V, Speziali G, D’Alessandro C, Cianchi C, Antonietta Grasso M, Spagnolo S, et al. Intraoperative low-volume acute normovolemic hemodilution in adult open-heart surgery. Anesthesiology. 2002; 97: 367–373. https://doi.org/10.1097/00000542-200208000-00013 PMID: 12151926
22. Barile L, Fominskiy E, Di Tomasso N, Alp`ızar Castro LE, Landoni G, De Luca M, et al. Acute normovole- mic hemodilution reduces allogeneic red blood cell transfusion in cardiac surgery: a systematic review and meta-analysis of randomized trials. Anesth Analg. 2017; 124: 743–752. https://doi.org/10.1213/ ANE.0000000000001609 PMID: 27669554
23. Oswald E, Streif W, Hermann M, Hengster P, Mittermayr M, Innerhofer P. Intraoperatively salvaged red blood cells contain nearly no functionally active platelets, but exhibit formation of microparticles: results of a pilot study in orthopedic patients. Transfusion. 2010; 50: 400–406. https://doi.org/10.1111/j.1537- 2995.2009.02393.x PMID: 19804574
24. Flom-Halvorsen HI, Øvrum E, Øystese R, Brosstad F. Quality of intraoperative autologous blood with- drawal used for retransfusion after cardiopulmonary bypass. Ann Thorac Surg. 2003; 76: 744–748. https://doi.org/10.1016/s0003-4975(03)00349-7 PMID: 12963190
25. Hayashida K, Murakami G, Matsuda S, Fushimi K. History and profile of diagnosis procedure combina- tion (DPC): development of a real data collection system for acute inpatient care in Japan. J Epidemiol. 2021; 31:1–11. https://doi.org/10.2188/jea.JE20200288 PMID: 33012777
26. Arpino B, Mealli F. The specification of the propensity score in multilevel observational studies. Comput Stat Data Anal. 2011; 55: 1770–1780.