title: Impact of mild preoperative renal insufficiency on in-hospital and long-term outcomes after off-pump coronary artery bypass grafting: a retrospective propensity score matching analysis.
abstract: BACKGROUND
  Mild preoperative renal insufficiency is not rare in patients receiving isolated off-pump coronary artery bypass grafting surgery (OPCAB) surgery. However, there is less study aimed to evaluate the impact of mild preoperative renal insufficiency on in-hospital and follow-up outcomes after isolated OPCAB surgery. This single-centre, retrospective propensity score matching study aimed to evaluate the impact of mild preoperative renal insufficiency on in-hospital and long-term outcomes after first isolated OPCAB surgery.
  
  
  METHODS
  After propensity score matching, 1236 patients with preoperative estimated glomerular filtration rate (eGFR) of more than 60 ml/min/1.73 m(2) undergoing first isolated OPCAB surgery from January 2007 to December 2011 were entered into this study and were divided to normal group (eGFR ≥ 90 ml/min/1.73 m(2), n = 618) and mild group (eGFR of 60-89 ml/min/1.73 m(2), n = 618). The in-hospital and long-term outcomes were investigated and retrospectively analyzed.
  
  
  RESULTS
  The 2 propensity score-matched groups had similar baseline and procedural characteristics except the baseline eGFR. Thirty-five patients died during the same hospitalization or within 30 days of operation, with a surgical mortality of 2.8 %. Sixty-seven patients died during follow-up, with a long-term survival of 94.1 %. Univariate factor analysis showed that the 2 propensity score-matched groups have similar rates among in-hospital outcomes. Kaplan-Meier curves displayed a similar in-hospital survival between the 2 groups (χ(2) = 0.728, p = 0.393), while a better long-term survival in patients with normal preoperative renal function compared with mild preoperative renal insufficiency (χ(2) = 4.722, p = 0.030). After Cox proportional model was used, the hazard ratio for long-term mortality in patients with mild preoperative renal insufficiency compared with normal preoperative renal function was 1.72 (95 % CI 1.06-2.83, p = 0.032).
  
  
  CONCLUSIONS
  Mild preoperative renal insufficiency compared with normal preoperative renal function reduced long-term survival, without evidence of worse in-hospital outcomes.
authors.affiliation: Department of Thoracic Cardiovascular Surgery of Tongji Hospital of Tongji University, Shanghai, 389 Xincun Rd., Shanghai, 200065, P. R. China. drjiqiang@tongji.edu.cn.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ji
authors.affiliation: Department of Cardiovascular Surgery of Zhongshan Hospital of Fudan University, Shanghai, 180 Fenglin Rd., Shanghai, 200032, P. R. China. xlm1117@126.com.
authors.forename: LiMin
authors.initials: L
authors.lastname: Xia
authors.affiliation: Department of Cardiovascular Surgery of Zhongshan Hospital of Fudan University, Shanghai, 180 Fenglin Rd., Shanghai, 200032, P. R. China.
authors.forename: YunQing
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Department of Cardiovascular Surgery of Zhongshan Hospital of Fudan University, Shanghai, 180 Fenglin Rd., Shanghai, 200032, P. R. China.
authors.forename: RunHua
authors.initials: R
authors.lastname: Ma
authors.affiliation: Shanghai Institute of Cardiovascular Disease, 180 Fenglin Rd., Shanghai, 200032, P. R. China.
authors.forename: ChunSheng
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Thoracic Cardiovascular Surgery of Tongji Hospital of Tongji University, Shanghai, 389 Xincun Rd., Shanghai, 200065, P. R. China. jiqiang1977@aliyun.com.
authors.forename: YunQing
authors.initials: Y
authors.lastname: Mei
authors.affiliation: Department of Cardiovascular Surgery of Zhongshan Hospital of Fudan University, Shanghai, 180 Fenglin Rd., Shanghai, 200032, P. R. China. dwj12191@163.com.
authors.forename: WenJun
authors.initials: W
authors.lastname: Ding
mesh_terms: D000368:Aged; D002681:China / Q000453:epidemiology; D047549:Coronary Artery Bypass, Off-Pump / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000401:mortality; D057216:Propensity Score; D016016:Proportional Hazards Models; D051437:Renal Insufficiency / Q000150:complications* / Q000401:mortality; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome