title: Cystatin C as a reliable marker of renal function following heart valve replacement surgery with cardiopulmonary bypass.
abstract: BACKGROUND
  Little is known about serum cystatin C as a marker of renal function in cardiac surgery patients. The aim of this study was to assess its utility post cardiopulmonary bypass (CPB).
  
  
  METHODS
  60 heart valve replacement patients were enrolled, and 26 of them had low-dose corticosteroid treatment on the first 3 days postoperatively. Serum creatinine, serum cystatin C and 24-h creatinine clearance rate (CCR) adjusted by body surface area were determined preoperation, days 1, 2, 3, 7 post operation.
  
  
  RESULTS
  Serum creatinine increased and peaked at day 3 postoperatively, while cystatin C peaked at day 2, and the adjusted CCR also reached a minimum at day 2. The inverse of cystatin C correlated better with CCR than that of creatinine (r=0.751 vs. 0.629). Using adjusted CCR as "golden standard", cystatin C was superior to creatinine in diagnosing renal dysfunction (area under the curve [AUC] for cystatin C 0.876, 95% confidence interval 81.8-93.4; AUC for creatinine 0.801, 95% confidence interval 72.5-87.7; p=0.045). Low-dose corticosteroid treatment has no significant effect on cystatin C.
  
  
  CONCLUSIONS
  In agreement with many other investigators, the present findings support cystatin C is a reliable marker of renal function. It is superior to creatinine in patients post CPB.
authors.affiliation: Department of Cardiothoracic Surgery, Jinling Hospital, Clinical Medicine School of Nanjing University, Nanjing 210002, China. doctor_zhujq@yahoo.com.cn
authors.forename: Jiaquan
authors.initials: J
authors.lastname: Zhu
authors.forename: Rong
authors.initials: R
authors.lastname: Yin
authors.forename: Haiwei
authors.initials: H
authors.lastname: Wu
authors.forename: Jun
authors.initials: J
authors.lastname: Yi
authors.forename: Liguo
authors.initials: L
authors.lastname: Luo
authors.forename: Guohua
authors.initials: G
authors.lastname: Dong
authors.forename: Hua
authors.initials: H
authors.lastname: Jing
mesh_terms: D000305:Adrenal Cortex Hormones / Q000494:pharmacology; D000328:Adult; D019540:Area Under Curve; D015415:Biomarkers / Q000032:analysis; D002315:Cardiopulmonary Bypass; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests
chemical_list: D000305:Adrenal Cortex Hormones; D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins