title: Impact of Ultrafiltration on Kidney Injury After Cardiac Surgery: The Michigan Experience.
abstract: BACKGROUND
  This study examines the relationship between the use and volume of conventional ultrafiltration (CUF) and the risk of acute kidney injury (AKI) after isolated on-pump coronary artery bypass graft surgery.
  
  
  METHODS
  A total of 6,407 consecutive patients underwent isolated on-pump coronary artery bypass graft surgery between 2010 and 2013 at 21 medical centers participating in the PERFusion Measures and Outcomes (PERForm) registry. We assessed the effect of CUF use on AKI and other postoperative sequelae using a generalized linear mixed-effect model with a logit link. We also modeled the effect of increasing volume of CUF per weight on AKI, and tested for any modification by a patient's preoperative kidney function.
  
  
  RESULTS
  Patients having CUF were more likely to have diabetes, vascular disease, chronic obstructive pulmonary disease, congestive heart failure, history of a myocardial infarction, or an intraaortic balloon pump (p < 0.05). They had lower preoperative and nadir hematocrits, creatinine clearance, and ejection fraction (p < 0.05). Patients exposed to CUF had higher adjusted risk of AKI (adjusted odds ratio, 1.36; p = 0.002), although similar rates of death, stroke, and reoperation for bleeding (p > 0.05). The risk of AKI was modified by a patient's preoperative kidney function (p < 0.0004). Among patients with a creatinine clearance of less than 99.6 mL/min (95% confidence interval, 67.6 to 137.5), increasing volume of CUF was associated with a higher risk of AKI.
  
  
  CONCLUSIONS
  Patients exposed to CUF had a higher adjusted risk of AKI. Clinical teams should consider lower volumes of CUF among patients with low creatinine clearance to minimize the risk of AKI.
authors.affiliation: Department of Cardiac Surgery, University of Michigan, Ann Arbor, Michigan.
authors.forename: Theron A
authors.initials: TA
authors.lastname: Paugh
authors.affiliation: Specialty Care, Nashville, Tennessee.
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Dickinson
authors.affiliation: St. John Macomb-Oakland Hospital, Warren, Michigan.
authors.forename: James R
authors.initials: JR
authors.lastname: Martin
authors.affiliation: William-Beaumont Hospital, Troy, Michigan.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Hanson
authors.affiliation: St. John Providence Health System Detroit Hospitals, Detroit, Michigan.
authors.forename: John
authors.initials: J
authors.lastname: Fuller
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: Michael
authors.initials: M
authors.lastname: Heung
authors.affiliation: Department of Biostatistics, University of Michigan, Ann Arbor, Michigan.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Division of Cardiac Surgery, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Shann
authors.affiliation: Department of Cardiac Surgery, University of Michigan, Ann Arbor, Michigan.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Prager
authors.affiliation: Department of Cardiac Surgery, University of Michigan, Ann Arbor, Michigan. Electronic address: likosky@med.umich.edu.
authors.forename: Donald S
authors.initials: DS
authors.lastname: Likosky
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D000368:Aged; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000601:surgery*; D005260:Female; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D015994:Incidence; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D016017:Odds Ratio; D011183:Postoperative Complications; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D014462:Ultrafiltration / Q000379:methods