Late-Onset De Novo Minimal Change Disease Presenting With Nephrotic Range Proteinuria More Than 1 Year After Combined Heart-Kidney Transplant: A Case Report.

We present a case of de novo minimal change disease occurring more than 1 year after transplant in a combined heart-kidney transplant recipient. A 68-year-old white man with past medical history of nonischemic cardiomyopathy with left-ventricular assist device and end-stage renal disease due to type 2 diabetes mellitus and cardiorenal syndrome underwent a combined heart-kidney transplant in a sequential manner in August 2016. He was induced with rabbit antithymocyte globulin and methylprednisolone; he was maintained on mycophenolate mofetil, tacrolimus, and a protocolized tapering dose of prednisone. More than 1 year after transplant, in December 2017, he had about 2.3 g of proteinuria. Kidney function remained stable with a creatinine of 1.2 mg/dL. Serologic and infectious workup was nonrevealing. Proteinuria peaked at 4.5 g in January 2018, and kidney biopsy results were consistent with minimal change disease. After the biopsy, his prednisone dosage was escalated to 80.0 mg daily and slowly tapered to 2.5 mg (including most recent follow-up data from May 2019) daily, in alignment with improvement in his proteinuria and creatinine. Proteinuria decreased to 130.0 mg/g. To our knowledge, this is the first reported case of its kind in a combined heart-kidney transplant patient.