Effect of Calcineurin Inhibitor-Free, Everolimus-Based Immunosuppressive Regimen on Albuminuria and Glomerular Filtration Rate After Heart Transplantation

Background. Albuminuria in maintenance heart transplantation (HTx) is associated with poor renal response when switching to a calcineurin inhibitor (CNI)-lowered or CNI-free immunosuppressive regimen using everolimus (EVR), but the significance of albuminuria associated with EVR treatment after early CNI withdrawal in de novo HTx is unknown. Methods. We tested if measured glomerular filtration rate (mGFR, by chrome-ethylenediaminetetraacetic acid clearance) was associated with urine albumin/creatinine ratio (UACR) post-HTx in a subgroup of patients included in the Scandinavian Heart Transplant Everolimus De Novo Study With Early Calcineurin Inhibitor Avoidance trial, where de novo HTx patients (n = 115) were randomized to EVR with complete CNI elimination 7 to 11 weeks post-HTx or standard CNI immunosuppression. Results. In 66 patients, UACR measures were available at 1 year. In 7 patients in the EVR group, a CNI was reintroduced within 12 months. Medianm GFR was significantly higher in the EVR group both 1 and 3 years post-HTx (P = 0.0004 and P = 0.03, respectively). Median UACR at 1 year was significantly higher in the EVR group (P = 0.002). There was no correlation between log(UACR) at 1 year and mGFR at 1 or 3 years (r = -0.01, P= 0.9 and r = 0.15, P = 0.26, respectively) and in the EVR group between log(UACR) at 1 year and change in mGFR (Delta 1-3 years) (r = 0.27, P = 0.14). Excluding patients in the EVR group in whom a CNI was reintroduced did not significantly change the results. Conclusions. The effects of EVR with early CNI withdrawal after HTx on albuminuria and renal function seem dissociated; hence, the clinical significance of albuminuria in this setting is uncertain and should not necessarily rule out EVR-based immunosuppression.