title: The Association of Anemia and Its Severity with Cardiac Outcomes and Mortality After Total Knee Arthroplasty in Noncardiac Patients.
abstract: BACKGROUND
  The purpose of this study is to assess whether an association exists between preoperative anemia and postoperative cardiac events or death in patients undergoing unilateral primary total knee arthroplasty (TKA) with no prior cardiac history.
  
  
  METHODS
  Data from the 2008-2012 American College of Surgeons National Surgical Quality Improvement Program database were analyzed. Patients aged ≥18 years undergoing unilateral primary TKA were included. We divided the patients into 4 groups: no anemia, any anemia, mild anemia, and moderate-severe anemia. Associations between anemia and different characteristics as well as cardiac outcomes and death were studied, after adjusting for all potential confounders.
  
  
  RESULTS
  In the nonanemic group, the occurrence of myocardial infarction, cardiac arrest, and death were 61 of 34,661 (0.18%), 23 of 34,661 (0.07%), and 30 of 34,661 (0.09%), respectively. The numbers in the anemia group were 23 of 6673 (0.34%), 9 of 6673 (0.13%), and 14 of 6673 (0.21%). These were not statistically different. The anemic group had higher odds for respiratory and renal morbidities and for receiving transfusions.
  
  
  CONCLUSIONS
  We found no association between preoperative anemia or its severity and myocardial infarction, cardiac arrest, or death up to 30 days postoperatively. This could potentially lower the bar for safe preoperative hematocrit levels for elective TKA, theoretically increasing the percentage of anemic patients undergoing the procedure. This, however, is at the expense of potential respiratory and renal insults.
authors.affiliation: Division of Orthopaedic Surgery, Department of Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Jad S
authors.initials: JS
authors.lastname: Chamieh
authors.affiliation: Biostatistics Unit, Clinical Research Institute, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Hani M
authors.initials: HM
authors.lastname: Tamim
authors.affiliation: Division of Orthopaedic Surgery, Department of Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Karim Z
authors.initials: KZ
authors.lastname: Masrouha
authors.affiliation: Division of Orthopaedic Surgery, Department of Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Said S
authors.initials: SS
authors.lastname: Saghieh
authors.affiliation: Division of Orthopaedic Surgery, Department of Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Muhyeddine M
authors.initials: MM
authors.lastname: Al-Taki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000150:complications*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000401:mortality*; D001803:Blood Transfusion / Q000706:statistics & numerical data; D002318:Cardiovascular Diseases / Q000209:etiology* / Q000401:mortality; D017558:Elective Surgical Procedures / Q000009:adverse effects / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology / Q000209:etiology; D011183:Postoperative Complications / Q000209:etiology* / Q000401:mortality; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
keywords: anemia; cardiac arrest; death; myocardial infarction; perioperative care; total knee arthroplasty