Large vein allografts are suitable for middle hepatic vein (MHV) reconstruction, but their supply is often limited. Although polytetrafluoroethylene (PTFE) grafts are unlimitedly available, their long-term patency is relatively poor. We intended to enhance the clinical usability of PTFE grafts for MHV reconstruction during living donor liver transplantation (LDLT). Two sequential studies were performed. First, PTFE grafts were implanted as inferior vena cava replacements into dogs. Second, in a 1-year prospective clinical trial of 262 adults undergoing LDLT with a modified right lobe, MHV reconstruction with PTFE grafts was compared with other types of reconstruction, and the outcomes were evaluated. In the animal study, PTFE grafts induced strong inflammatory reactions and luminal thrombus formation, but the endothelial lining was well developed. In the clinical study, the reconstruction techniques were revised to make a composite PTFE graft with an artery patch on the basis of the results of the animal study. MHVs were reconstructed with cryopreserved iliac veins (n ¼ 122), iliac arteries (n ¼ 43), aortas (n ¼ 13), and PTFE (n ¼ 84), and these reconstructions yielded 6-month patency rates of 75.3%, 35.2%, 92.3%, and 76.6%, respectively. The overall 6-month patency rates for the iliac vein and PTFE grafts were similar (P ¼ 0.92), but the 6-month patency rates with vein segment 5 were 51.0% and 34.7%, respectively (P ¼ 0.001). The overall graft and patient survival rates did not differ among these 4 groups. In conclusion, ringed PTFE grafts combined with small vessel patches showed high patency rates comparable to those of iliac vein grafts; thus, they can be used for MHV reconstruction when other sizable vessel allografts are not available. Liver Transpl 18:955-965, 2012. V C 2012 AASLD.Received December 6, 2011; accepted March 19, 2012.Middle hepatic vein (MHV) reconstruction with an interposition vessel graft has been established as a standard procedure for living donor liver transplantation (LDLT) with a right lobe graft when the donor's MHV trunk is preserved in the donor's remnant liver.Materials used to date for this type of venous vascular reconstruction have included various types of homologous and autologous vessel grafts. [1][2][3][4][5] The recent increase in the number of adult LDLT procedures and the relatively limited number of vessel allografts have Abbreviations: CT, computed tomography; GRWR, graft-to-recipient weight ratio; IVC, inferior vena cava; LDLT, living donor liver transplantation; MELD, Model for End-Stage Liver Disease; MHV, middle hepatic vein; PTFE, polytetrafluoroethylene; V5, hepatic vein branch segment 5; V8, hepatic vein branch segment 8.
Surgical methods guided by exogenous fluorescent markers have the potential to define tissue types in real time. Small molecule dyes with efficient and selective renal clearance could enable visualization of the ureter during surgical procedures involving the abdomen and pelvis. These studies report the design and synthesis of a water soluble, net neutral C4'-O-alkyl heptamethine cyanine, Ureter-Label (UL)-766, with excellent properties for ureter visualization. This compound is accessed through a concise synthetic sequence involving an N- to O-transposition reaction that provides other inaccessible C4'-O-alkyl heptamethine cyanines. Unlike molecules containing a C4'-O-aryl substituent, which have also been used for ureter visualization, UL-766 is not reactive towards glutathione and the cellular proteome. In addition, rat models of abdominal surgery reveal that UL-766 undergoes efficient and nearly exclusive renal clearance in vivo. In total, this molecule represents a promising candidate for visualizing the ureter during a variety of surgical interventions.
In liver transplantation, a left lateral section (LLS) graft may have an unusual variant left hepatic vein (LHV) anatomy. This study was designed to analyze the incidence of unusual LHV variants and to determine technical methods for effective reconstruction in infant recipients weighing approximately 10 kg or less. The study comprised 3 parts: an LHV variation analysis, a simulation-based design for the technical modification of graft LHV venoplasty, and its clinical application. The LHV anatomy of 300 potential LLS graft donors was classified into 4 types according to the number and location of the hepatic vein openings: (1) a single opening (n ¼ 218 or 72.7%); (2) 2 large adjacent openings (n ¼ 29 or 9.7%); (3) 2 adjacent openings, 1 large and 1 small (n ¼ 34 or 11.3%); and (4) 2 widely spaced openings (n ¼ 19 or 6.3%). Types 2 and 3 required wedged unification venoplasty, and type 4 required additional vein interposition. In a series of 49 cases using LLS grafts, the graft hepatic vein complication rate was 4.5% at 3 years; stenting was necessary for 1 of the 36 type 1 LHV grafts (2.8%) and for 1 of the 13 type 2-4 LHV grafts (7.7%, P ¼ 0.46). A customized interposition-wedged unification venoplasty technique for coping with type 4 vein variations was developed with a simulation-based approach, and it was successfully applied to a 10-month-old male infant receiving an LLS graft with a type 4 LHV. In conclusion, nearly all LHV variations can be effectively managed with customized unification venoplasty. These venoplasty techniques represent beneficial surgical options as part of graft standardization for hepatic vein reconstruction in pediatric living donor liver transplantation.
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