Abstracts
1997 Digestive Disease Week

Cold ischemia of more than 10 hours reduces graft quality in clinical liver transplantation.

E Klar, M Angelescu, Th Kraus, M Bredt, A Mehrabi, G Otto, C Herfarth. Department of Surgery, University of Heidelberg, Heidelberg, Germany.

As previously demonstrated intraoperative liver perfusion below 60 ml/100g/min is associated with poor liver function and primary graft failure after transplantation. Cold ischemia time is generally accepted as a determinant of graft quality. It was the aim of this prospective study to define the maximum duration of cold ischemia beyond which a reduction of graft quality can be detected concerning critical impairment of hepatic microcirculation, increase of AST, and extent of postoperative fresh-frozen-plasma (FFP) substitution.

Methods: In 33 patients a thermodiffusion probe was placed into segment IV during orthotopic liver transplantation. Liver perfusion was quantified intraoperatively 60 min after reperfusion. As indicators of graft function the maximum increase of serum AST (AST_max) and the amount of FFP-administration was recorded postoperatively. By these parameters graft quality was compared within vs. beyond certain ischemia time intervals ranging from 8 to 15 hours (60-min steps) using Fisher's exact test or Mann-Whitney U-Test. The aim was to define the maximum length of ischemia time without significant difference.

Results: A negative correlation was detected between the duration of cold ischemia and intraoperative liver perfusion (r=0.57, p<0.001, Spearman rank correlation). Up to a cold ischemia time of 10 hrs. no patient was recorded with a hepatic perfusion below the the critical value of 60 ml/100g/min. Cold ischemia of more than 10 hours resulted in a significant impairment of hepatic microcirculation (Fisher's exact test, p<0.01) as well as in a significant increase in the number of patients with AST_max above 1000 U/L (p<0.05) or postoperative requirement of FFP-substitution (p<0.01).

Conclusion: Hepatic microcirculation as one main determinant of graft quality is significantly influenced by the duration of cold ischemia. However, up to a cold storage time of 10 hours graft function is not significantly reduced with respect to the critical range of hepatic perfusion, maximum postoperative serum AST, or the necessity of FFP-administration.