title: Renal function after cardiac surgery off- versus on-pump coronary artery bypass: analysis using the Cockroft-Gault formula for estimating creatinine clearance.
abstract: BACKGROUND
  Cardiopulmonary bypass (CPB) is often associated with renal dysfunction, as measured by plasma creatinine levels and hemodialysis rates. This study compared creatinine clearance (CrCl), estimated with the Cockroft and Gault formula, between patients undergoing off-pump coronary artery bypass grafting (OPCAB) versus on-pump CABG (on-CAB).
  
  
  METHODS
  Data of 704 consecutive patients were analyzed. Of these patients, 404 underwent OPCAB while 300 had on-CAB. Creatinine clearance, plasma creatinine levels, and clinical outcome were compared between groups. Data between patients who developed new renal impairment, compared to patients with normal postoperative renal function, were also analyzed.
  
  
  RESULTS
  Creatinine clearance (preoperative, 74 +/- 25 vs 78 +/- 29 mL/min; day 1, 74 +/- 26 vs 76 +/- 31 mL/min; day 4, 70 +/- 26 vs 72 +/- 29 mL/min) and creatinine levels (preoperative, 99 +/- 25 vs 95 +/- 27 micromol/L; day 1, 101 +/- 29 vs 104 +/- 35 micromol/L; day 4, 110 +/- 44 vs 113 +/- 60 micromol/L), as well as postoperative complications (stroke 1% vs 1%; hemofiltration 1.5% vs 3.7%; death 1.2% vs 2.3%), were overall similar between OPCAB and on-CAB patients. Patients with preoperative CrCl less than 50 mL/min had higher creatinine levels in the on-CAB group on day 1 (p = 0.026), although CrCl was similar between groups. Development of new CrCl less than 50 mL/min postoperatively was associated with higher rates of intraaortic balloon pump insertion, re-sternotomy, hemofiltration, intensive care and hospital stay, without difference between groups. Female sex, low body mass index, high preoperative creatinine levels, and advanced age were associated with deterioration in CrCl.
  
  
  CONCLUSIONS
  Currently, the rate of renal impairment is low after both OPCAB and on-CAB. No significant difference in CrCl could be demonstrated between groups. Deterioration in renal function is associated with higher rates of postoperative complications.
authors.affiliation: Department of Cardiothoracic Surgery, St. George's Hospital, London, United Kingdom.
authors.forename: George
authors.initials: G
authors.lastname: Asimakopoulos
authors.forename: A Paul
authors.initials: AP
authors.lastname: Karagounis
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Valencia
authors.forename: Nicholas
authors.initials: N
authors.lastname: Alexander
authors.forename: Mohamed
authors.initials: M
authors.lastname: Howlader
authors.forename: Mazin A
authors.initials: MA
authors.lastname: Sarsam
authors.forename: Venkatachalam
authors.initials: V
authors.lastname: Chandrasekaran
mesh_terms: D000368:Aged; D001026:Coronary Artery Bypass / Q000379:methods*; D047549:Coronary Artery Bypass, Off-Pump / Q000379:methods*; D003324:Coronary Artery Disease / Q000601:surgery; D003404:Creatinine / Q000378:metabolism*; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D011183:Postoperative Complications; D012189:Retrospective Studies
chemical_list: D003404:Creatinine