Background: The proportion of elderly individuals is growing and the prevalence of chronic kidney disease (CKD) among elderly people undergoing cardiac surgery is increasing constantly. The aim of this study was to determine the influence of different degrees of preoperative renal dysfunction on postoperative outcomes in patients older than 80years of age.
Methods: This is an observational study that included adult patients undergoing cardiac surgery in which data were collected prospectively. Patients were divided into groups according to their preoperative plasma creatinine and eGFR levels.
Results: From February 1997 to January 2010, 318 octogenarians underwent cardiac surgery. Of these, 140 patients (44%) had abnormal preoperative creatinine levels. A significantly higher incidence of postoperative sepsis (4% vs. 17%, p 0.03), CVA (1% vs. 6%, p 0.03), and prolonged hospital stay (16±13 vs. 20±16days, p 0.04) were detected in patients with preoperative kidney dysfunction. Subgroup analysis revealed that preoperative CKD stage IV (eGFR 15-30ml/min/1.73m(2)) but not CKD stage III (eGFR 30-60ml/min/1.73m(2)) and preoperative creatinine >1.8mg/dl were independently associated with increased incidence of postoperative CVA (OR 4; 95% CI 0.07-0. 8, p=0.05 for eGFR, and OR 7.8; 95% CI 1.2-60, p=0.003 for creatinine). However, no significant increment in postoperative mortality with decreasing eGFR or increasing preoperative creatinine was demonstrated.
Conclusions: A substantial increase in the risk of postoperative CVA and sepsis, but not mortality, was demonstrated in octogenarians with advanced but not mild degrees of preoperative CKD. Compared to younger patients, a high burden of comorbidities in octogenarians may have a greater influence on outcomes post cardiac surgery than impaired renal function. Our data may provide a rationale for modified risk stratification in octogenarian candidates for cardiac surgery.
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