Abstract: 【Abstract】Objectives Patients with severe renal dysfunction undergoing cardiac surgery still are associated with many complications and higher mortality. The present study aimed to investigate the relationship between prEoperative maintenance hemodialysis (MHD) and 30-day mortality after cardiac surgery in patients with estimated glomerular filtration rate (eGFR) <30ml/min/1.73m2. Methods A total of 272 severe renal dysfunction patients undergoing cardiac surgery during the period between Jan. 2010 and Oct. 2020 were retrospectively studied. Multivariate COX proportional hazard was used to estimate hazard ratio (HR) and 95% confidence interval (CI) of the risk for 30-day mortality after the surgery. Results In the 272 severe renal
dysfunction patients undergoing cardiac surgery, 73.2% were male, the average age was 61.4±9.5years, 85 patients (31.3%) had regular MHD before the surgery, and their 30-days mortality after the surgery was 16.9%. COX regression analyses showed that prEoperative MHD reduced the 30-day mortality (HR=0.399, 95% CI 0.160～0.996, P=0.049), and that rEoperation (HR=4.287, 95% CI 1.717～10.705, P=0.002), lower post-operative left ventricular ejection fraction (LVEF<40%) (HR=3.251, 95% CI 1.581～6.685, P=0.001), more intraoperative blood loss (HR=1.133, 95% CI 1.033～1.242, P=0.008), and longer post-operative ventilator time (HR=1.457, 95% CI 1.230～0.909, P=0.024) were the risk factors for higher 30-day mortality, but male patients (HR= 0.457, 95% CI 0.230～0.909, P=0.024) had a lower risk of mortality. Conclusions Patients with severe renal dysfunction undergoing cardiac surgery were associated with many complications and higher mortality. PrEoperative MHD before cardiac surgery reduced the 30-day mortality.

Key words: Maintenance hemodialysis, Severe renal dysfunction, Cardiac surgery, 30-day mortality