Substantial Recovery of Renal Function Is Uncommon Early Post Cardiac Transplant Irrespective of Pre-Transplant LVAD Support

Abstract

Purpose Marked early recovery of renal function (RRF) is common after LVAD placement, with nearly half of patients experiencing ≥ 50% improvement in GFR in the first several weeks. However, this substantial RRF has not been observed early post-transplant (Tx). It is possible that the negative effects of acute calcineurin inhibitor (CNI) nephrotoxicity negate the improvement in GFR that would otherwise be seen with RRF post-Tx. If this hypothesis is correct, and given the fact that bridge-to-Tx LVAD patients should have already experienced RRF, acute CNI nephrotoxicity should act unopposed in these patients resulting in a large reduction in GFR. Methods and Materials A random sample of cardiac transplants at our center, oversampled for LVADs, with serial creatinine levels available were reviewed (n=138). Significant RRF was defined as a ≥50% improvement in GFR. Results The incidence of significant RRF was only 10.4% at 30 days and the mean GFR of the cohort was worse at all post-Tx time points compared to baseline (Figure). The magnitude of GFR deterioration was not different between patients with (n=65) or without (n=73) a pre-tx LVAD (p-interaction=0.51, Figure). At 30 days, decreases in GFR were similar between patients with CNI levels above or below the median (-1.2%, ± 35.1% vs. -2.6% ± 49.6%, p=0.86), both in patients with (p=0.69) and without (p=0.79) a pre-Tx LVAD. [ figure 1 ] Conclusions Meaningful RRF appears to be uncommon, even early post-Tx before chronic CNI nephrotoxicity is apparent. This finding is not significantly influenced by pre-Tx LVAD support or early CNI levels. Further research is needed to better understand changes in renal function following advanced therapies.