title: Hemoglobin and renal replacement therapy after cardiopulmonary bypass surgery: a predictive score from the Cardiac Surgery Registry of Puglia.
abstract: BACKGROUND
  Acute Kidney Injury (AKI) after cardiac surgery is a complication influencing postoperative outcome. Preoperative hemoglobin is a predictor of postoperative AKI. We aimed to identify preoperative predictors of Renal Replacement Therapy (RRT) and to develop a new risk-scoring system including hemoglobin to better stratify the risk of events.
  
  
  METHODS
  We evaluated 3288 consecutive patients of the Regional Cardiac Surgery Registry of Puglia operated in 2011-2012. Chronic dialysis and renal transplantation patients were excluded. Primary outcome was post-operative RRT incidence.
  
  
  RESULTS
  The study sample was divided in two cohorts: 1642 patients (70 RRT) operated during the year 2011 as derivation cohort and 1646 patients (69 RRT) of the year 2012 as validation. In a multivariable logistic regression model using a stepwise method, six preoperative risk factors were associated with RRT in the derivation cohort: creatinine clearance, preoperative hemoglobin, neurological dysfunction, left ventricular ejection fraction, urgency and combined procedures (discrimination c-index 0.844 and 0.818 in the validation cohort). Scoring system included risk factors obtained from derivation cohort adjusting their relative weight with updated rounded coefficients in the validation cohort: creatinine clearance<50ml/min (1 point), hemoglobin≤12.5g/dl (1 point), left ventricular ejection fraction≤30% (1 point), urgent operation (1 point), emergency-salvage surgery (2 points), and combined procedures (1 point). In both cohorts, outcomes were strongly correlated with score points.
  
  
  CONCLUSIONS
  Our simple bedside prognostic score demonstrates good performance in predicting RRT. Hemoglobin plays an important role and future studies will clarify if preoperative anemia correction will lead to decreased RRT risk.
authors.affiliation: Division of Cardiac Surgery, Department of Emergency and Organ Transplant (D.E.T.O.), University of Bari "Aldo Moro", Bari, Italy. Electronic address: domenico.paparella@uniba.it.
authors.forename: Domenico
authors.initials: D
authors.lastname: Paparella
authors.affiliation: Health Regional Agency of Puglia (AReS Puglia), Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Guida
authors.affiliation: Division of Cardiac Surgery, Villa Bianca Clinic, Bari, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Mazzei
authors.affiliation: Division of Cardiac Surgery, Villa Bianca Clinic, Bari, Italy.
authors.forename: Carmine
authors.initials: C
authors.lastname: Carbone
authors.affiliation: Division of Cardiac Surgery, Anthea Hospital, Villa Maria Group, Bari, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Speziale
authors.affiliation: Division of Cardiac Surgery, Villa Verde Clinic, Taranto, Italy.
authors.forename: Vitantonio
authors.initials: V
authors.lastname: Fanelli
authors.affiliation: Division of Cardiac Surgery, Vito Fazzi Hospital, Lecce, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Zaccaria
authors.affiliation: Division of Cardiac Anesthesia, Santa Maria Hospital, Bari, Italy.
authors.forename: Cataldo
authors.initials: C
authors.lastname: Labriola
authors.affiliation: Division of Cardiac Surgery, Department of Emergency and Organ Transplant (D.E.T.O.), University of Bari "Aldo Moro", Bari, Italy; Division of Cardiac Surgery, Vito Fazzi Hospital, Lecce, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Scrascia
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002315:Cardiopulmonary Bypass / Q000009:adverse effects* / Q000639:trends; D015331:Cohort Studies; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012042:Registries; D017582:Renal Replacement Therapy / Q000639:trends; D012720:Severity of Illness Index
chemical_list: D006454:Hemoglobins
keywords: Cardiac surgery; Cardiopulmonary Bypass; Hemoglobin; Kidney