Evaluation of Long-Term Kidney Function Following Orthotopic Heart Transplantation

Introduction: Acute impairment of kidney function in patients with heart failure and heart transplantation is a frequent condition. However, the impact of the transplant on long-term kidney function remains controversial. Methods: This study describes a cohort of patients who received a heart transplant in a reference hospital between 2005 and 2019. Glomerular filtration rate during follow-up was calculated at 0, 6,12, 24, and 60 months using the Cockcroft-Gault and MDRD (modification of diet in renal disease study) equations. To identify changes we compared glomerular filtration rate (GFR) at baseline with measurements over time after heart transplantation, using a paired t test and a longitudinal model of Generalized Estimating Equations (GEE). Results: Forty-four patients were included. The mean of baseline GFR was 67.9 ± 1.3 mL/min. A triple immunosuppressive therapy scheme was used with cyclosporine/tacrolimus, mycophenolate mofetil, and steroid, with progressive dose reduction. After adjusting for multiple variables, we found no reduction of GFR over time with the GEE model. There was no significant difference in GFR using Cockcroft-Gault equation at 6 (mean difference [MD] 4.46; confidence interval [CI] –2.1 to 11.09; P = 0.18), 12 (MD 1.65, CI -4.5 to 7.82; P = 0.59), 36 (MD 0.69; CI –6.04 to 7.43; P = 0.83), and 60 months (MD 0.62; CI –5.5 to 6.79; P = 0.83). Similar findings were found using MDRD equation. Conclusions: There is no significant GFR decline between the time of heart transplantation and a follow-up at 60 months. New studies are needed to evaluate changes in renal function beyond this timeframe.