Enhanced virtual crossmatch in intestinal transplantation: association with outcomes and application in practice.

Background: The presence of preformed donor-specific antibodies in recipient serum against anti-human leukocyte antigen is a significant risk factor that negatively affects the outcomes of intestinal transplantation. Avoiding high-risk intestinal transplantation by physical and virtual cross matches has had limited success due to time constraints and ineffective correlation, respectively. Methods: We developed a guideline to improve the association between physical and virtual cross matches using the retrospective data of 56 consecutive primary adult isolated intestinal transplantations from a single center. Results: The mean fluorescence intensity of 2,000 for positive donor-specific antibodies revealed the best association between physical and virtual cross matches among different cut-off values, but with an unacceptable false positive rate of 54%. An enhanced virtual cross match with the summation of the mean fluorescence intensity of each anti-human leukocyte antigen improved the association between physical and virtual cross matches, with a sensitivity of 83% and specificity of 98%. Conclusions: This enhanced virtual cross match more effectively predicts high-risk intestinal transplantation and is a better substitute for physical cross-match than the current virtual cross match. It also helps to avoid ill-considered abandonment of intestinal transplantation that is unnecessarily deemed high risk based on a simple virtual cross match.

Identification of the anterior sectoral trunk with particular reference to the hepatic hilar plate and its clinical importance.

BACKGROUND: At the hilum of the liver, there is a structure called the hilar plate, which is of great surgical importance because all variations in the bile ducts and blood vessels occur within this region. The Rex-Cantlie line does not always pass the point of portal bifurcation. Classifying portal vein (PV) variations based on the shape and origin of anterior sectoral trunk (AST) within the hepatic plate system will be of higher anatomical and surgical value than the conventional method based on PV ramification. METHODS: We investigated PV variations in the hilar plate in terms of combinations of 4 hepatic sectoral trunks rather than successive ramification of the PV. The combination patterns of each sectoral trunk were analyzed using data from adult cadaver liver dissection (n = 64) and multi-detector computed tomography (n = 216) of human livers. RESULTS: The AST root position on the hilar plate varies, in contrast to the other sectoral trunks, which are relatively consistent in their root position. Three types of PV variations were identified based on the AST root position. In addition, 4 similar but different shapes (I, Y, V, and U) of AST were identified. CONCLUSION: Not only the root position in the hepatic hilar plate but also the shape of AST can be considered as the major determinants of PV variations.

Anatomical variations of the origin of the segment 4 hepatic artery and their clinical implications.

The threat of ischemic complications following massive resection, especially in living donor hepatectomy or split liver transplantation, has been haunting surgeons for many years. Postmortem dissections of 62 livers were performed to investigate anatomical variations of the principal artery for segment 4 (A4). The origin of A4 was examined separately in the liver with (n = 46) or without (n = 16) an aberrant left hepatic artery (abLHA). A4s were found to be extrahepatic or intrahepatic branches of the right hepatic artery (RHA), left hepatic artery, or proper hepatic artery and were categorized into 4 different types according to their origins. The RHA type, originating from the RHA or right anterior hepatic artery (RAHA), was the most common pattern in our series. The A4 roots had a strong tendency of stemming from the RHA (n = 12) even in the livers with abLHA (n = 16). Among the RHA-type A4s, the A4 arising from RAHA (n = 2) is supposed to be the most dangerous variant because it can cause an ischemic change in the remaining part of the liver after right hepatectomy. In conclusion, in the era of living donor liver transplantation, paying particular attention to the point of origin of A4 is a prerequisite, especially when the lateral section is relatively small. Arterial injuries to A4 during split liver transplantation may also increase the risk of hepatic artery thrombosis and ischemic cholangiopathy.

Utilization of dried blood spot citrulline level as a noninvasive method for monitoring graft function following intestinal transplantation.

BACKGROUND: Citrulline concentrations have been proposed as a marker for intestinal allograft rejection. We instituted dried blood spot (DBS) specimen monitoring of citrulline to simplify sample collection posttransplant. This study demonstrates the correlation between plasma and dried blood spot specimen citrulline concentrations after intestinal transplantation. METHODS: Plasma and DBS samples were analyzed by hydrophilic interaction chromatography tandem mass spectrometry. Comparison of the strength of linear correlation was made according to the type of surgery, sonication time, DBS citrulline levels, and the time interval between the blood sample collection and the assay date. RESULTS: A very strong linear correlation exists between the plasma and DBS citrulline concentrations (r=0.87; P<0.001). The correlation between plasma and DBS citrulline concentrations was maintained when evaluating only the intestinal transplant recipients. There was no significant difference in the strength of linear correlation according to sonication time, cirtrulline concentrations, or length of time to assay date. CONCLUSIONS: DBS citrulline monitoring will ease sample collection following intestinal transplantation and improve the ability to detect intestinal dysfunction and rejection by a noninvasive means.

Effect of radiofrequency ablation of the liver on cell-mediated immunity in rats.

We investigated the effect of radiofrequency ablation (RFA) of the liver on cell-mediated immunity in rats. Sprague-Dawley rats were divided into five groups: control group that did not have any procedure, a sham-operation group that underwent laparotomy, a lobectomy group that had left lateral lobectomy of the liver, a one-lobe RFA group that had RFA on the left lateral lobe of the liver, and a two-lobe RFA group that had RFA on the left lateral and left median lobe of the liver. Delayed-type hypersensitivity (DTH) was induced by challenging the ears of previously sensitized rats with 2,4-dinitro-1-fluorobenzene. Cell-mediated immunity was evaluated by direct measurement of the ear thickness and quantitative analysis of leukocytic infiltration of the tissue. The increased ear thickness was 42.0%, 69.2%, 61.8%, 46.7%, and 39.8% from the baseline one day after each procedure, and the mean leukocytic infiltration into the ear tissue was 3136.7, 3895.0, 3913.3, 2803.3, and 2316.7/mm(2) seven days after each procedure in the control, sham-operation, lobectomy, one-lobe RFA, and two-lobe RFA groups, respectively. In conclusion, RFA of the liver tissue can partially abolish the augmentation of DTH and leukocytic infiltration those were seen in the hepatic lobectomy and sham-operation groups. The procedure had a negative effect on cell-mediated immunity in rats, and the intensity of RFA showed a reverse correlation with cell-mediated immunity.

Arterial reconstruction with donor iliac vessels during pancreas transplantation: an intraoperative approach to arterial injury or inadequate flow.

BACKGROUND: Outcome of pancreas transplantation (PTX) has improved because of use of novel immunosuppression and advances in surgical technique. It is not uncommon for severe atherosclerosis in patients with type 1 insulin-dependent diabetes mellitus or the presence of a previously transplanted organ to limit the options for vascular anastomosis. Herein we report the novel application of donor iliac arterial interposition grafts for arterial reconstruction in patients with severe iliac artery arteriosclerosis, and/or previous transplant who develop an arterial injury or stenosis during surgery. METHODS: In five patients undergoing PTX, the external iliac artery was severely atherosclerotic and/or occupied by a previous vascular anastomosis. In four of the five patients, an arterial intimal dissection became apparent. The external iliac artery was excised and reconstructed with donor iliac artery interposition graft (end-to-end anastomosis). Pancreas or kidney was engrafted onto this arterial interposition graft (end-to-side anastomosis). RESULTS: There was no operative morbidity related to this surgical approach. All grafts functioned well after transplantation. Distal lower extremities have no evidence of vascular insufficiency with mean follow-up of 26 months (7-45 months). CONCLUSION: This surgical technique is an acceptable option during PTX for the patient with severe iliac artery arteriosclerosis with intraoperative intimal dissection or stenosis, or perhaps those with challenging arterial access.

Estimation of standard liver volume for liver transplantation in the Korean population.

The standard liver volume (LV) of a recipient is estimated in liver transplantation to determine the minimum LV necessary for the recipient. Simple linear formulas of LV estimation were developed for the Japanese and Caucasian populations. The present study examined the applicability of the reported formulas to the Korean population. Liver density (LD) was determined by analyzing 24 healthy livers. Data of liver weight (LW), body weight (BW), body height (BH), body surface area (BSA), and age were obtained from 652 postmortem examination reports (age, 42.4 +/- 16.5 years) showing normal livers. The LV of each subject was estimated by LW / LD and the relationships between LV, BW, BSA, and age were analyzed. LD was 1.04 +/- 0.07 kg/L. LV / BW decreased as age increased in the children but leveled off in the adults; the rate of increase in LV along with BSA in individuals with BSA <1.2 m(2) appeared less than the corresponding rate in individuals with BSA >/=1.2 m(2). The Japanese formula produced underestimates for the Korean population (226.9 +/- 289.4 mL), while the Caucasian formula produced random errors (-30.64 +/- 281.5 mL). A better LV estimation formula was established: LV (mL) = 21.585 x BW (kg)(0.732) x BH (cm)(0.225) (adjusted R(2) = 0.59; SE = 275.8 mL). In conclusion, this study indicates that a nonlinear or piecewise linear model is more desirable than a simple linear model for LV estimation in children and adults, because LV / BW and LV / BSA are not constant with age and BSA.

Intestinal and multivisceral transplantation.

Intestinal transplantation has been established as a treatment option for patients that suffer from intestinal failure with complications from total parenteral nutrition. It is still rapidly evolving and just reached a landmark of 1,000 cases worldwide. Intestinal allografts can be transplanted as isolated, combined with the liver or as a part of a multivisceral allograft. Tacrolimus-based immunosuppression regimens have been used universally with improved outcomes. Clinical outcome in intestinal transplantation has improved significantly over time, impacted by refinement of surgical technique and novel immunosuppression. However rejection, infection, and technical complications still remain the most difficult barrier to improve patient and graft survival.