Effect of iloprost on the microcirculation and liver function after orthotopic liver transplantation

Introduction

Iloprost, a prostacyclin analogon, can probably improve the microcirculation in various tissues. It may have a positive effect on perfusion and function of the liver, especially in patients after liver transplantation. We therefore estimated liver function with the indocyanine green (ICG) plasma disappearance rate (PDR). We also evaluated iloprost effects on microcirculation in the oral mucosal tissue.

Methods

Sixteen patients after orthotopic liver transplantation were randomly included in the study. They received either iloprost (n = 9) or placebo (n = 7). Iloprost was given in a dose of 1 ng/kg/min. The oral mucosal tissue oxygen saturation, microcirculatory blood flow and blood flow velocity were measured in a depth of one with a laser Doppler flowmetry and remission spectroscopy system (O2C; LEA, Gießen, Germany). The ICG-PDR was determined with the LIMON (Pulsion, München, Germany). All measurements were performed 6 hours, 12 hours, 24 hours, 48 hours, 72 hours and 96 hours postoperatively.

Results

We saw a significant increase in the microcirculatory blood flow and blood flow velocity 6 and 12 hours postoperatively in the iloprost group in comparison with the placebo group. After 6 hours the blood flow was 156 (minimum, 54; maximum, 460; without units) in the placebo group and 213 (minimum, 57; maximum, 456; P < 0.05) in the iloprost group. After 12 hours it was 175 (minimum, 53; maximum, 483) and 318 (minimum, 86; maximum, 569; P < 0.05), respectively. The blood flow velocity was 18 (minimum, 14; maximum, 50) in the placebo group and 29 (minimum, 17; maximum, 51; P < 0.05) in the iloprost group 6 hours postoperatively. Twelve hours postoperatively the velocity was 21 (minimum, 16; maximum, 52) and 37.5 (minimum, 19; maximum, 64; P < 0.05). The oral mucosal tissue oxygen saturation did not change. We could not find any difference in the ICG-PDR between the two groups.

Conclusion

Iloprost improved the microcirculatory blood flow and blood flow velocity of the oral mucosa in the early postoperative phase. This effect did not lead to an improved ICG clearance in patients after liver transplantation.