Is ATG Induction with Delayed Initiation of CNI Protective of Renal Function in Patients with Mild Renal Insufficiency?

Rabbit anti-thymocyte globulin (ATG) therapy has been used for induction to allow delay of initiation of calcineurin inhibitor (CNI) immediately post-heart transplant (HTx) in patients with moderate to severe renal insufficiency. In our program, this approach has been routine for patients with serum creatinine >2.0 mg/dL. Although this mode of therapy has been shown to be effective for renal protection, its benefit has not been established for patients with less renal insufficiency, in the 1.5-2.0 mg/dL range. Therefore, we reviewed our patient population to assess whether ATG induction was renal-protective for these patients. Between 2010 and 2020, we assessed 84 patients with baseline creatinine in the 1.5-2.0 mg/dL range who underwent HTx, and divided them into those who underwent ATG with delay of initiation from CNI to those patients who did not. Patients given ATG (x 5 days) had delayed CNI beginning on days 3-5 post-operatively once urine output was established. Endpoints included comparison of glomerular filtration rate (GFR) at baseline, with change at 6- and 12-months for each group. In addition, 1-year freedom from temporary and chronic dialysis (occurring greater than 30 days postop) and freedom from rejection (any treated rejection [ATR], acute cellular rejection [ACR], antibody mediated rejection [AMR]) was assessed. There was no significant difference in the ATG induction compared to control in renal function (creatinine/GFR) at baseline and change in GFR at 6 months and 1 year post-HTx. In addition, there was no difference between groups in 1-year freedom from temporary or chronic dialysis, and freedom from ATR, ACR, or AMR. ATG induction with delay of CNI does not appear beneficial for kidney function in patients with mild renal insufficiency. Larger studies are needed to confirm these findings. [ABSTRACT FROM AUTHOR]