Relationship between renal function and left ventricular assist device use

Background. Poor renal function may affect outcomes after left ventricular assist device (LVAD) placement. Conversely, LVADs may optimize circulation and improve renal function. Methods. To assess the relationship between renal function and LVAD use, changes in creatinine clearances (CrCl, in mL/min) were assessed retrospectively in 220 patients who underwent LVAD placement. These patients were also divided into four groups based on CrCl quartiles (< 47, 48-68, 69-95, and > 95) and compared for outcomes post-LVAD placement. Results. Eighty-four patients died on LVAD support. Survival on LVAD was worse for patients with the worst baseline CrCl (42%, 52%, 63%, and 79% for 6 month and 26%, 34%, 47%, and 66% for 12 month survival for quartiles 1-4; both p < 0.01 for trend). Adjusting for other covariates, patients in the lowest CrCl quartile were at a higher risk of dying postimplant (odds ratio 1.95, 95% confidence interval 1.14-3.63). Paired sample analysis showed the following changes in CrCl: preoperative to week 1, 77.0 +/- 46.6 to 92.1 +/- 51.1 (p < 0.01; n = 202), week 1 to 2, 89.4 +/- 49.2 to 95.2 +/- 52.4 (p = 0.01, n = 171), week 2 to 3, 107.5 +/- 58.1 to 113.7 +/- 66.1 (p = 0.16, n = 74), and week 3 to 4, 111.1 +/- 56.6 to 110.5 +/- 56.8 (p = 0.87, n = 60). For the 60 patients with baseline CrCl less than 50, CrCl increased from 36.7 +/- 9.2 to 60.1 +/- 35.5 (p < 0.01; n = 55 pairs) from preimplant to week 1. In 37 of these patients (62%) on intraaortic balloon pump support preimplant, CrCl increased from 38.4 +/- 8.2 to 67.9 +/- 40.3 mL/minute (p < 0.01) during week 1 postimplant. Recovery of renal function to CrCl greater than 50 was associated with a trend towards better 30-day survival (84% vs 66%, p = 0.09). Conclusions. Baseline poor renal function is associated with worse outcomes after LVAD implantation. However, renal function improves substantially and rapidly in post-LVAD survivors and is associated with improved outcomes. These data underscore the importance of careful patient selection for LVAD therapy.