Renal replacement therapy and orthotopic liver transplantation: the role of continuous veno-venous hemodialysis.

BACKGROUND: The need for renal replacement therapy (RRT) either before or after orthotopic liver transplant (OLTX) has been reported to be a poor prognostic indicator for survival. Use of continuous veno-venous hemodialysis (CVVHD) for RRT has been reported in three series of OLTX patients with high 90-day mortality rates of 57-60%. We have examined our patient population to determine the effect of necessity and type of RRT on patient survival after OLTX.
METHODS: We analyzed 1535 OLTX that were performed at our institution from 1985 through 1999, 1037 from 1985 to 1995 (period I) and 498 from 1996 to 1999 (period II). Combined liver-kidney transplants were excluded from analysis. Hospital dialysis unit records and a prospectively maintained database on all OLTX patients served as the source of data. Patients were classified into groups defined on whether or not they received RRT, when they received RRT, and the type of RRT. Groups were compared for preoperative intensive care unit status, time on the waiting list, laboratory variables, 90-day postoperative mortality, 1-year patient survival, and absolute survival.
RESULTS: Use of RRT increased from 8.29% in period I to 12.45% in period II, along with increased median waiting times. In period I, patients receiving preoperative RRT had a 90-day mortality (0%) and a 1-year survival (89.5%) almost identical to those patients who never required RRT (1.7% and 90.6%). Patients who developed acute renal failure postoperatively requiring RRT, however, had a 90-day mortality of 28.6% and a 1-year survival of 55%. In period II, patients requiring RRT had a 90-day mortality of 39.7% and a 1-year actuarial survival of 54.5% compared with 6.9% and 88.6% in patients never requiring RRT. Patients treated with CVVHD had a 90-day mortality of 42% compared with 25% in patients treated with hemodialysis alone. However, patients receiving CVVHD both pre- and postoperatively had a 90-day mortality of 27.7% vs. 50% in those patients who only received CVVHD postoperatively. Patients who developed acute renal failure postoperatively, which required RRT, regardless of therapy, had a 1-year survival of only 41.0% compared with a 1-year survival of 73.6% in those patients started on RRT preoperatively, P=0.03.
CONCLUSIONS: The need for RRT has increased along with waiting time in OLTX patients. Patients developing the need for RRT postoperatively have an increased 90-day mortality and lower 1-year survival with the highest being present in patients receiving CVVHD, which was started postoperatively. These findings may reflect a trend toward a sicker population awaiting OLTX and emphasize the negative impact of renal failure on survival after OLTX.