Small-for-Size Syndrome: Systemic Review in a Porcine Experimental Model.

BACKGROUND: The small-for-size syndrome (SFSS) is characterized by prolonged hyperbilirubinemia, coagulopathy, and/or encephalopathy caused by a small liver graft that cannot sustain the metabolic demands of the recipient after a partial liver transplant (PLT). Models of PLT in pigs are excellent for studying this syndrome. This review aimed to identify the different porcine models of SFSS in the literature and compare their technical aspects and therapeutics methods focused on portal inflow modulation (PIM). METHODS: We performed a systematic review of the porcine experimental model and SFSS. The MEDLINE-PubMed, EMBASE, Cochrane Library, LILACS, and SciELO databases were electronically searched and updated until June 20, 2021. The MeSH terms used were ''ORGAN SIZE'' AND ''LIVER TRANSPLANTATION". RESULTS: Thirteen SFSS porcine models were reported. Four were performed with portocaval shunt to PIM and 3 with mesocaval shunt to PIM. A few studies focused on clinical therapeutics to PIM; a study described somatostatin infusion to avoid SFSS. Initially, studies on PIM showed its potentially beneficial effects without mentioning the minimum portal flow that permits liver regeneration. However, an excessive portal diversion could be detrimental to this process. CONCLUSIONS: The use of porcine models on SFSS resulted in a better understanding of its pathophysiology and led to the establishment of various types of portal modulation, surgical techniques with different complexities, and pharmaceutical strategies such as somatostatin, making clear that without reducing the portal vein pressure the outcomes are poor. With the improvement of these techniques, SFSS can be avoided.

Experimental Clinical Model of Liver Transplantation in Large White Pigs Without Venovenous Bypass: Pre-, Intra-, and Maintenance Care.

BACKGROUND: Liver transplantation in an animal model is challenging due to hemodynamics and intraoperative anesthetic care. Several models are described in the literature employing different techniques such as venovenous bypass or aortic cross-clamping to maintain hemodynamic stability, although few groups keep the animal alive in the postoperative period. This study aims to evaluate a liver transplantation clinical model in pigs without venovenous bypass or aortic cross-clamping. METHODS: Male pigs weighing 20 to 35 kg underwent liver transplantation surgery without using venovenous bypass or aorta cross-clamping. Protocols were approved by the Animal Care and Use Committee of the University of São Paulo, Brazil. RESULTS: Ten LTs were performed. Cold ischemia and warm ischemia were 119 ± 33.28 minutes and 26 ± 9.6 minutes, respectively. Hemodynamic changes were significantly higher after the postrevasculazation phase: heart rate (P < .001), medium arterial pressure (P < .001), and cardiac output (P = .03). Hypotension was treated with intravenous fluids and, in some cases, with vasoactive drugs especially during the post-reperfusion period. No animals died during the procedure and almost survival until the first postoperative day. Serum aspartate aminotransferase and lactate increased their values in the post-reperfusion phase. CONCLUSIONS: Practice-based on laboratory animals improves surgical skills and the development of experimental models aimed at new advances in this field. Perfecting our technique on the swine model, we could move forward to create a small-for-size model, test new therapeutic strategies, and define the boundaries for safely performing an enlarged liver resection or a partial liver graft transplant.

Septuagenarian Donors and Recipients in Deceased Donor Liver Transplantation: A Brazilian Single Center Experience and Literature Review.

BACKGROUND: The number of elderly patients who have end-stage liver disease and require liver transplantation has dramatically increased. On the other hand, liver grafts from elderly donors have been offered more frequently for transplantation. The present study aims to analyze the results of liver transplants performed with donors and recipients aged ≥70 years. METHODS: We performed a single-center retrospective study of deceased donors liver transplants that involved recipients aged ≥7070 years or recipients who received grafts from donors aged ≥70 years from 2011 to 2021. A literature review on the results of liver transplantation in elderly recipients was also performed. RESULTS: Thirty septuagenarian recipients were included; their overall 1- and 5-years survival was 80% and 76.6%, respectively. The prevalence of recipients aged ≥70 years in our department was 2.65%. Twenty recipients received grafts form septuagenarian donors; their overall 1- and 5-years survival was 75%. The prevalence of donors aged ≥70 years in our department was 1%. In the literature review, 17 articles were analyzed. The 5-years survival of recipients aged ≥70 years ranged from 47.1% to 78.5%. CONCLUSIONS: Septuagenarian recipients and patients who received grafts from elderly brain-dead donors present adequate overall survival after liver transplantation. Optimized donor-recipient matching is paramount for achieving good outcomes. The combination of high-risk donors with septuagenarian recipients should be avoided as well as using grafts of elderly donors that present others risk factors. Thus, the age of the donor or recipient alone cannot be considered an absolute contraindication for liver transplantation.

Incidence of Donor Hepatic Artery Thrombosis in Liver Grafts Recognized During Organ Procurement and Backtable: A Rare but Treacherous Pitfall In Liver Transplantation.

INTRODUCTION: Donor hepatic artery thrombosis (dHAT) identified during liver procurement and backtable is a rare and little-reported event that can make liver transplants unfeasible. METHODS: This is a retrospective study of dHAT identified during liver grafts procurements or backtable procedures. All grafts were recovered from brain-dead donors. The demographic characteristics of the donors and the incidence of dHAT were analyzed. The data were also compared to a cohort of donors without dHAT. RESULTS: There was a total of 486 donors during the study period. The incidence of dHAT was 1.85% (n = 9). The diagnosis of dHAT was made during procurement in 5 cases (55.5%) and during the backtable in 4 (44.4%). Most donors were female (n = 5), with an average BMI of 28.14 ± 6.9 kg/m2, hypertensive (n = 5), and with stroke as cause of brain death (n = 8). The most prevalent site of dHAT was a left hepatic artery originating from the left gastric artery (n = 4). Of the 9 cases reported, 2 livers were used for transplantation, and 7 were discarded. Comparing those cases to a cohort of 260 donors without dHAT, we found a higher incidence of anatomic variations in the hepatic artery (P = .01) and of stroke as cause of brain death (P = .05). CONCLUSION: The occurrence of dHAT before liver procurement is a rare event, however it may become a treacherous pitfall if the diagnosis is late. Grafts with anatomic variations recovered from women with brain death due to stroke and with past history of hypertension seem to be at a higher risk of presenting dHAT.