Amelia J. Hessheimer

Evaluation of tumor response after locoregional therapies in hepatocellular carcinoma: are response evaluation criteria in solid tumors reliable?

Evaluation of response to treatment is a key aspect in cancer therapy. Response Evaluation Criteria in Solid Tumors (RECIST) are used in most oncology trials, but those criteria evaluate only unidimensional tumor measurements and disregard the extent of necrosis, which is the target of all effective locoregional therapies. Therefore, the European Association for the Study of the Liver (EASL) guidelines recommended that assessment of tumor response should incorporate the reduction in viable tumor burden. The current report provides an assessment of the agreement/concordance between both RECIST and the EASL guidelines for the evaluation of response to therapy.

Liver Transplant Using Donors After Unexpected Cardiac Death: Novel Preservation Protocol and Acceptance Criteria

Donors after cardiac death (DCD) suffer irreversible cardiac arrest prior to donation. We describe our liver transplant experience with DCD whose cardiac arrest is unexpected, not following the removal of ventilatory support, whom we maintain with normothermic extracorporeal membrane oxygenation (NECMO). A potential donor goes into cardiac arrest outside the hospital and is brought to the hospital under continuous cardiopulmonary resuscitation (CPR). The donor is declared dead and placed on a cardiocompressor. Femoral vessels are cannulated and connected to cardiopulmonary bypass (CPB) to establish NECMO. Blood parameters and CPB pump flow are monitored throughout NECMO, which is continued until cold preservation. From April 2002 to May 2006, 10 of 40 potential DCD livers were transplanted. Only one graft was lost to primary nonfunction (PNF) and another to hepatic artery thrombosis. Posttransplant hepatic function was good. Certain parameters, such as CPR and NECMO times, hepatic transaminases during NECMO, and donor age, determined the viability of DCD liver grafts and were used to establish criteria for their acceptance. Though considered marginal, unexpected DCD can represent an important source of viable livers for transplant if strict acceptance criteria are employed and they are maintained with NECMO prior to recovery.

Superior Preservation of DCD Livers With Continuous Normothermic Perfusion

Objective:Unexpected donation after cardiac death (DCD) donors suffer cardiac arrest suddenly and are maintained with normothermic extracorporeal membrane oxygenation (NECMO) while consent for donation is obtained. The objective of this study was to determine whether ex vivo normothermic machine perfusion (NMP) improves upon the benefits of NECMO in a large-animal model of unexpected DCD liver transplant. Methods:Donor pigs underwent 90-minute cardiac arrest and were divided in to 3 groups. In the first, livers were preserved immediately with cold storage (CS, n = 6). In the other 2 groups, donors underwent 60-minute NECMO followed by CS (NECMO+CS, n = 6) or NMP (NECMO+NMP, n = 6). After 4–hour preservation, livers were transplanted into recipient pigs. Results:Five-day survival was 0 in CS, 83% in NECMO+CS, and 100% in NECMO+NMP. After reperfusion, injury, and inflammatory markers rose significantly among CS grafts, all of which developed primary nonfunction. Sixty minutes of NECMO, however, resulted in only 1 death, whereas NECMO followed by NMP led to no deaths and significant improvements in injury, inflammation, and synthetic function in comparison to NECMO and CS. Conclusion:Although 60 minutes recuperative NECMO is better than CS alone, NMP improves further on NECMO and may have a role in preserving DCD livers in the clinical setting.

Applicability and Results of Maastricht Type 2 Donation After Cardiac Death Liver Transplantation

Maastricht type 2 donation after cardiac death (DCD) donors suffer sudden and unexpected cardiac arrest, typically outside the hospital; they have significant potential to expand the donor pool. Herein, we analyze the results of transplanted livers and all potential donors treated under our type 2 DCD protocol. Cardiac arrest was witnessed; potential donors arrived at the hospital after attempts at resuscitation had failed. Death was declared based on the absence of cardiorespiratory activity during a 5‐min no‐touch period. Femoral vessels were cannulated to establish normothermic extracorporeal membrane oxygenation, which was maintained until organ recovery. From April 2002 to December 2010, there were 400 potential donors; 34 liver transplants were performed (9%). Among recipients, median age, model for end‐stage liver disease and cold and reperfusion warm ischemic times were 55 years (49–60), 19 (14–21) and 380 (325–430) and 30 min (26–35), respectively. Overall, 236 (59%) and 130 (32%) livers were turned down due to absolute and relative contraindications to donate, respectively. One‐year recipient and graft survivals were 82% and 70%, respectively (median follow‐up 24 months). The applicability of type 2 DCD liver transplant was <10%; however, with better preservation technology and expanded transplant criteria, we may be able to improve this figure significantly.

Hypothermic Oxygenated Machine Perfusion in Porcine Donation After Circulatory Determination of Death Liver Transplant

Background Livers from donation after circulatory determination-of-death (DCD) donors suffer ischemic injury during a preextraction period of cardiac arrest and are infrequently used for transplantation; they have the potential, however, to considerably expand the donor pool. We aimed to determine whether hypothermic oxygenated machine perfusion would improve or further deteriorate the quality of these livers using a clinically relevant porcine model. Methods Donor livers were subjected to 90 min of cardiac arrest and preserved at 4°C with either static cold storage using University of Wisconsin solution (CS, n=6) or oxygenated machine perfusion using University of Wisconsin machine perfusion solution and 25% physiological perfusion pressures (HMP, n=5). After 4 hr of preservation, livers were transplanted into recipient pigs, which were followed intensively for up to 5 days. Results Five-day survival was 0 in CS and 20% in HMP. Immediately after reperfusion, hepatocellular injury and function were improved in HMP versus CS. However, HMP grafts also demonstrated significant endothelial and Kupffer cell injury, and a progressive lesion developed 24 to 48 hr after reperfusion that led to death in all but one of the recipient animals. Conclusions Although hypothermic oxygenated machine perfusion performed using subphysiological perfusion pressures seems to offer some advantages over cold storage in the preservation of ischemically damaged livers, it simultaneously conditions endothelial and Kupffer cell injury that may ultimately lead to the failure of these grafts.

Decompression of the portal bed and twice-baseline portal inflow are necessary for the functional recovery of a "small-for-size" graft.

Background.In partial liver transplant, a reduction in the intrahepatic vascular bed produces a rise in the portal vein flow and the portal venous pressure gradient, leading to endothelial and, thereby, hepatocellular injury and death in a process known as “small-for-size” (SFS) syndrome. Objective.To demonstrate that a calibrated portocaval shunt prevents superfluous inflow in a porcine model of SFS transplant. Methods.Donor pigs (15–20 kg) underwent 70% hepatectomy. In 2 groups, a 6 mm (S6) (n = 6) or 12 mm (S12) (n = 6) Gore-Tex shunt was placed between the portal vein and infrahepatic inferior vena cava. In a third group, no portocaval shunt was placed (SFS) (n = 17). Grafts were stored for 5 hours at 4°C and then transplanted into recipients (30–35 kg). Results.Five-day survival was 29% in SFS, 100% in S6, and 0 in S12. Postreperfusion portal vein flow was 4-, 2-, and 1-times flow at baseline in SFS, S6, and S12, respectively. With respect to portal venous pressure gradient, both the 6- and 12-mm shunts effectively decompressed the portal bed. Aspartate aminotransferase and bilirubin rose and the Quick prothrombin time fell in all animals after reperfusion but improved significantly by day 5 in S6. Serum levels of endothelin-1 remained elevated in SFS and S12 but returned to baseline by 12 hours in S6: 2.76 (2.05–4.08) and 2.04 (1.97–2.12) versus 0.43 (0.26–0.50) pg/mL, respectively (P < 0.05 for both comparisons). Conclusions.A calibrated portocaval shunt that maintains portal vein flow about twice its baseline value produces a favorable outcome after SFS liver transplantation, avoiding endothelial injury due to portal hyperperfusion or to hypoperfusion because of excess shunting.

Extracorporeal machine liver perfusion: are we warming up?

Purpose of reviewRecently, considerable focus has been placed on the use of hypothermic perfusion ex vivo in abdominal organ transplant. Herein, we discuss the appropriateness of using this modality to preserve livers, in particular those of suboptimal quality, and whether perfusing at warmer temperatures in this context may, in fact, be better. Recent findingsHypothermic perfusion (0–4°C) appears to improve the hepatocellular energy charge and achieve adequate results in normal livers. However, its use for the preservation of suboptimal grafts may lead to significant endothelial and Kupffer cell injury that is incompatible with survival. Studies on the perfusion of suboptimal livers at higher temperatures, on the contrary, indicate that results improve as temperatures approach 37°C, provided that the oxygen supply during perfusion is adequate. SummaryNormothermic perfusion provides oxygen and other metabolic substrates under physiological conditions; in liver transplant, it appears to be the best option to improve the viability of suboptimal organs.

Hypothermic or normothermic abdominal regional perfusion in high-risk donors with extended warm ischemia times: impact on outcomes?

Donation after circulatory determination of death (DCD) has the potential to increase the applicability of transplantation as a treatment for end‐stage organ disease; its use is limited, however, by the warm ischemic damage suffered by potential grafts. Abdominal regional perfusion (ARP) has been employed in this setting to not only curtail the deleterious effects of cardiac arrest by re‐establishing oxygenated flow but also test and even improve the viability of the kidneys and liver prior to transplantation. In the present review article, we discuss experimental and clinical studies that have been published to date on the use of ARP in DCD, differentiating between its application under hypothermic and normothermic conditions. In addition to describing results that have been achieved thus far, we describe the major obstacles limiting the broader implementation of ARP in this context as well as potential means for improving the effectiveness of this modality in the future.

Can we prevent ischemic‐type biliary lesions in donation after circulatory determination of death liver transplantation?

The pool of livers for transplantation consists of an increasingly greater proportion of marginal grafts, in particular those arising through donation after circulatory determination of death (DCD). However, a primary factor limiting the use of marginal livers, and, thereby, the applicability of liver transplantation in general, is concern over the subsequent development of ischemic‐type biliary lesion (ITBL). ITBL is a devastating complication of liver transplantation; in its most severe forms, recipients suffer frequent infectious complications that require repeated invasive biliary procedures and ultimately result in either retransplantation or death. In the present review article, we discuss our current understanding of ITBL pathogenesis as it pertains to DCD, in particular. We discuss the most relevant theories regarding its development and provide a comprehensive overview of the most promising strategies we have available today to prevent the appearance of ITBL, strategies that may, furthermore, allow us to transplant a greater proportion of marginal livers in the future. Liver Transplantation 22 1025–1033 2016 AASLD

Can we prevent ischemic type biliary lesion in DCD liver transplantation

The pool of livers for transplantation consists of an increasingly greater proportion of marginal grafts, in particular those arising through donation after circulatory determination of death (DCD). However, a primary factor limiting the use of marginal livers, and, thereby, the applicability of liver transplantation in general, is concern over the subsequent development of ischemic‐type biliary lesion (ITBL). ITBL is a devastating complication of liver transplantation; in its most severe forms, recipients suffer frequent infectious complications that require repeated invasive biliary procedures and ultimately result in either retransplantation or death. In the present review article, we discuss our current understanding of ITBL pathogenesis as it pertains to DCD, in particular. We discuss the most relevant theories regarding its development and provide a comprehensive overview of the most promising strategies we have available today to prevent the appearance of ITBL, strategies that may, furthermore, allow us to transplant a greater proportion of marginal livers in the future. Liver Transplantation 22 1025–1033 2016 AASLD