Risk factors for intraoperative portal vein thrombosis in pediatric living donor liver transplantation

Abstract

Pathologic changes of the recipient native portal venous system may cause thrombosis of the portal vein, especially in pediatric living donor liver transplantation (LDLT). This study assessed the utility of Doppler ultrasound (US) for the detection of intraoperative portal vein occlusion and identification of predisposing risk factors in the recipients. Seventy-three pediatric recipients who underwent LDLT at Chang Gung Memorial Hospital, Taiwan, from 1994 to 2002 were included. Preoperative and intraoperative Doppler US evaluation of the portal vein was performed. Age, body weight, native liver disease, type of graft, graft recipient weight ratio (GRWR), type of portal anastomosis, portal velocity, portal venous size and presence of portosystemic shunt were analyzed for statistical significance of predisposing risk factors. Eight episodes of intraoperative portal vein thrombosis, with typical findings of absent Doppler flow in portal vein and prominent hepatic artery with a resistant index lower than 0.5 (p < 0.001), were detected during transplantation, which was then corrected by thrombectomy and re-anastomosis. Children age < or =1 yr (p = 0.025), weight < or =10 kg (p = 0.024), low portal flow < or =7 cm/s (p = 0.021), portal venous size < or =4 mm (p = 0.001), and GRWR >3 (p < 0.017) were all risk factors for intraoperative portal vein thrombosis. Doppler US is essential in the preoperative evaluation, early detection and monitoring of outcome of the portal vein in liver transplant.

Analysis of factors associated with portal vein thrombosis in pediatric living donor liver transplant recipients

“…It occurs during the follow‐up period, and the patients commonly present with ascites, gastrointestinal bleeding, and hypersplenism (an enlarged spleen and a low platelet count). There are technical aspects related to the portal reconstruction per se that can increase the incidence of thrombosis: short vascular stumps in LDLT (anastomoses under tension), a size discrepancy between the donor and recipient vascular structures, anastomotic misalignment, stenosis, anastomotic kinks, a low portal flow (<7 cm/s), a small PV (<4 mm), and the use of interposition VGs . PVCs can also be secondary to other technical problems: venous outflow obstructions (increased resistance in the liver), graft compression, pretransplant thrombosis, high hematocrit, high hepatic arterial flow, prior splenectomy, and portosystemic shunts (decreased portal flow) .…”

Living donor liver transplantation for children in Brazil weighing less than 10 kilograms

“…A new technical challenge came up after LDLT became an option: the use of large‐for‐size left lateral segment grafts in small children or infants may result in serious hemodynamic problems, including hepatic outflow obstruction, portal vein thrombosis (PVT), poor perfusion of the graft (as a result of compression and/or low portal flow) leading to graft dysfunction or nonfunction, difficulty in abdominal wound closure, and ventilatory problems 3, 4. Children <1 year of age, with 10 kg or less of body weight, low portal flow (≤7 cm/s), small portal venous size (≤4 mm), and GRWR >3% are strongly associated with PVT 5…”

Alternatives for vascular reconstruction in pediatric living donor liver transplantation

“…Many authors have described the techniques for PV reconstruction in pediatric LDLT . The technical issues are related to the use of short vascular stumps in LDLT, size discrepancies between the donor and recipient vascular structures, anastomotic misalignment, stenosis, anastomotic kink, low portal flow (<7 cm/s) and small PV (<4 mm) . Ueda et al , in the largest series of pediatric LDLT, reported focusing on PV reconstruction and complications (521 patients), showed that most of the reconstructions were performed in the PV trunk/branch patch (54%) or with the use of interposition vascular grafts (29%).…”