Renal Comorbidity After Heart and/or Lung Transplantation
After heart, lung or combined heart–lung transplantation, patients are at high risk for acute kidney injury (AKI) in the postoperative phase. A high percentage of patients require dialysis early after transplantation (6%). In this group of patients, the mortality rate was significantly increased to about 50%. Furthermore, a high percentage of patients with AKI developed chronic kidney disease (CKD) after lung transplantation. The decrease in renal function is very rapid during the first 6 postoperative months and slowly stabilizes after 2 years in those who survive. Preexisting CKD is one of the major risk factors for the development of pTxCKD. However, to differentiate between preexisting CKD and prerenal AKI can be a challenging task, not only in patients with end-stage heart failure. In such cases patient history, ultrasound and laboratory data (especially proteinuria) and a biopsy are necessary to differentiate the different causes. Even repeated renal biopsies may be performed in patients with end-stage heart failure to differentiate between CKD and prerenal AKI, as renal scarring may occur fast in these cases. In patients with a pretransplant GFR < 30 mL/min/1.73 m a combined heart and kidney transplantation is recommended. There is some evidence about less nephrotoxic effects of tacrolimus compared to cyclosporine A, for lung transplantation, this issue remains controversial. The risk of rejection of the graft has to be considered when alternative substances are used instead of calcineurin inhibitors (CNIs). This might be a potential option for selected patients but not in the early postoperative phase. Therefore, CNI-free protocols are not routinely applied in heart- and lung transplantation. Moreover, as we described earlier, the early combination of cyclosporine A and everolimus can rarely lead to posttransplant hemolytic uremic syndrome/thrombotic microangiopathy (TMA) in lung transplant recipients; Table 1).