Impact of renal function before mechanical circulatory support on posttransplant renal outcomes.

Background: Renal dysfunction is common before mechanical circulatory support (MCS). Mechanical circulatory support frequently improves renal function, but the impact of pre-MCS renal dysfunction on renal function after cardiac transplantation (CTX) is unknown.

Methods: Patients with MCS from January 1995 until April 2008 at a single center were included if their MCS duration was at least 60 days and they underwent successful CTX. Patients were followed for 1 year after CTX.

Results: A total of 116 patients were included in the study. Mechanical circulatory support was biventricular assist device in 28% and left ventricular assist device in 72% (continuous flow left ventricular assist device, 14%). Mean duration of MCS was 124 days. Patients were grouped according to tertiles of pre-MCS creatinine clearance (CrCl): group 1, CrCl less than 45 mL/min; group 2, CrCl between 45 and 65 mL/min inclusive; and group 3, CrCl more than 65 mL/min. Group 3 had the best renal outcomes both after MCS and 1 year after CTX. Regardless of group, patients who had a CrCl of at least 60 mL/min before CTX had similar 1-year posttransplant CrCl (55 versus 53 versus 56 mL/min for groups 1 through 3, respectively; not significantly different). However, the ability to achieve this level of renal function after MCS was less likely in those with the worst renal function before the initiation of MCS (53% versus 74% versus 90% for groups 1 through 3, respectively; p=0.001).

Conclusions: The use of MCS leads to improvements in renal function in patients after MCS. However, the renal outcomes after CTX seem to be more dependent on the level of renal function achieved during MCS than on the level of renal function before MCS.