ANALYSIS OF RISK FACTORS OF HEPATIC ARTERY THROMBOSIS INCIDENCE IN A CONSECUTIVE SERIES OF 687 LIVER TRANSPLANTATIONS.

Abstract

Aim: The aim of this retrospective study was to characterize the risk factors of hepatic artery thrombosis (HAT) after orthotopic liver transplantation (OLT) in a consecutive series of 687 OLT, comparing the branch patch anastomosis (BPA) with the end-to-end anastomosis (EEA), in order to investigate, moreover, which technique may be statistically associated with a reduced incidence of HAT.

Methods: Between 1986-1999 we performed 687 OLT in 601 patients, of which 592 were adult and 95 pediatric. Preservation of all donor livers was accomplished with the University of Wisconsin solution since OLT N° 112, at the beginning of 1990. A multivariate analysis was performed in order to find independent variables influencing HAT. We compared, between the two study groups EEA (n = 340) vs BPA (n = 347), HAT incidences with the following variables: adult OLT; pediatric OLT; pre ’90 period; post ’90 period; donor age; ABO incompatibility; graft type; cold ischemia time; warm ischemia time; double anastomoses; retransplantation; whole blood, fresh frozen plasma and platelet transfusions.

Results: HAT was identified in 17/687 OLT (2.47%). HAT incidence was 2.0% in adults (12/592) and 5.2% in children (5/95) (p = 0.059). In the EEA group, HAT was diagnosed in 12/340 cases (3.53%), whereas in the BPA group 5/347 patients experienced HAT (1.44%) (p = 0.078). The need of back table reconstruction occurred in 2/17 HAT cases (11.7%). Possible causative factors included rejection in 5 patients, whereas were unknown in 7 cases. A clear mechanical cause for HAT was identified in one patient, in whom a mechanical intraabdominal compression caused poor inflow. In two cases an intimal dissection was found, while poor inflow occurred in two cases. After a univariate analysis of 44 variables, compared between the two study groups (EEA vs BPA) in patients who developed HAT after OLT (n = 17), only intraoperative PT (p = 0.0525), postoperative SGOT (48 h) (p =0.0006) and postoperative SGPT (48 h) (p = 0.0222) correlated significantly with the occurrence of HAT. After a multivariate analysis, the variables found to be independent in increasing HAT incidence were: pre ’90 period (HAT incidence was 4.5 times more frequent in the pre ’90 period: p = 0.0093), ABO incompatibility (HAT incidence was 7.8 times more frequent in incompatible cases: p = 0.0363) and a shorter warm ischemia time (p = 0.0112).

Discussion: HAT after OLT is more common in the pediatric population, where it occurs in 10% to 26% of the cases, considerably higher than the 1.6% to 10.5% rate seen in the adult patients. In our series the risk of thrombosis was 2.6 times greater in children than in adults. Moreover, after a multivariate analysis, it was observed that the EEA was associated with an increased risk of thrombosis (2.4 times greater than in the BPA group). In this retrospective study we described a large number of variables, that may influence the development of HAT after OLT, identifying a group of risk factors that correlated statistically with this complication. The results of our report stressed the importance of medical factors compared with surgical factors in the incidence of HAT.

Conclusions: Even if the type of arterial reconstruction was not found to be an independent risk factor in reducing HAT incidence after OLT, our current preferred method of arterial anastomosis is the branch patch technique, using the hepatic-gastroduodenal bifurcation, with a HAT rate of 1.44%.