Does the Stage of Chronic Kidney Failure Influence the Outcome in Cardiac Surgery?

The number of patients with chronic kidney failure requiring cardiac surgery is continuously increasing. Additionally, significant worsening in the overall risk profile of this group of patients is noted.

To investigate the effect of chronic renal dysfunction both in non-dialysis-dependent renal failure and end-stage renal failure patients, on early mortality--morbidity and late survival in a series of cardiac surgery patients at our institution.

1344 patients who had open heart surgery at our university hospital between 2010 and 2013 were retrospectively reviewed. Chronic renal dysfunction was defined according to preoperative glomerular filtration rate. Patients selection (n=80). Group 1 mild--(GRF 59-30 mL/min), Group 2 moderate--(GFR 29-15 mL/min), Group 3 end stage--(GFR<15 mL/min) renal failure.

Chronic renal dysfunction was present in 5.95% of all patients studied. Group 1--55 (68.75%), Group 2--16 (20%), Group 3--9 (11.25%). No difference between the groups in the need for heart inotropic support was noted; however the use of these medications was necessary in 60.6% of all studied patients. Forty nine percent in Group 1, 87.5% in Group 2 and 77% in Group 3, respectively. Renal replacement therapy in the early postoperative period was needed in 12 patients, with significance between the groups (p = 0.001). The overall hospital mortality was 2.5%. Follow-up was completed with a mean of 1.4 years (range 2 months to 4 years). There were 6 (7.5%) late deaths.

Our observations do not exhibit large variations in postoperative complications and deaths in patients with chronic renal failure, depending on the degree of preoperative renal function impairment. It seems that renal failure regardless of the degree of impairment is a factor aggravating the intra and post-operative course in cardiac surgery patients.