Outcomes of severely impaired renal function patients with and without dialysis following isolated coronary artery surgery - a retrospective cohort study.

Objectives: Patients with advanced-stage chronic renal failure have poor outcomes following cardiac surgery. Our registry study aimed to compare postoperative and follow-up data between patients who underwent isolated coronary artery surgery with preoperative chronic dialysis and patients with preoperative severe renal impairment who did not require chronic dialysis.

Methods: We analyzed 157 948 consecutive adult patients in the Polish National Registry of Cardiac Surgical Procedures (KROK Registry) scheduled for isolated coronary artery surgery between January 2010 and December 2023. Overall, in this cohort, 938 patients underwent chronic dialysis (CD group), and 13 253 patients had severe renal impairment but did not undergo CD (serious renal impairment [SRI] group). Patients in these groups constituted 0.6% and 8.4% of the entire population, respectively. Preoperative data, major postoperative complications, hospital mortality, and mid-term all-cause mortality were compared among patients in CD group and SRI group.

Results: Mean age of patients CD group and SRI group was 63.3 ± 9.5 vs. 71.9 ± 8.4 years, respectively (P < 0.001), while the mean EuroSCORE II score in these groups was 4.85% ± 7.03% vs. 5.82% ± 7.76%, respectively (P < 0.001). In-hospital mortality among patients in the CD and SRI groups were 10.9% and 6.3%, respectively (P < 0.001). Patients with preoperative CD had more frequent respiratory complications and reoperations for bleeding. The long-term mortality was also significantly higher in CD group (P < 0.001).

Conclusion: Patients with CD had higher in-hospital and long-term mortality rates than those with a preoperative SRI. It is possible that the EuroSCORE II underestimates the risk of coronary bypass grafting in a group of patients with chronic dialysis. It is possible that the coagulation disorders may play role in the higher mortality rates in patients undergoing chronic dialysis.