Håkon Haugaa

Pivotal preclinical trial of the spheroid reservoir bioartificial liver

BACKGROUND & AIMS The neuroprotective effect of the spheroid reservoir bioartificial liver (SRBAL) was evaluated in a porcine model of drug-overdose acute liver failure (ALF). METHODS Healthy pigs were randomized into three groups (standard therapy (ST) alone, ST+No-cell device, ST+SRBAL device) before placement of an implantable intracranial pressure (ICP) monitor and a tunneled central venous catheter. One week later, pigs received bolus infusion of the hepatotoxin D-galactosamine and were followed for up to 90h. RESULTS At 48h, all animals had developed encephalopathy and biochemical changes confirming ALF; extracorporeal treatment was initiated and pigs were observed up to 90h after drug infusion. Pigs treated with the SRBAL, loaded with porcine hepatocyte spheroids, had improved survival (83%, n=6) compared to ST alone (0%, n=6, p=0.003) and No-cell device therapy (17%, n=6, p=0.02). Ammonia detoxification, peak levels of serum ammonia and peak ICP, and pig survival were influenced by hepatocyte cell dose, membrane pore size and duration of SRBAL treatment. Hepatocyte spheroids remained highly functional with no decline in mean oxygen consumption from initiation to completion of treatment. CONCLUSIONS The SRBAL improved survival in an allogeneic model of drug-overdose ALF. Survival correlated with ammonia detoxification and ICP lowering indicating that hepatocyte spheroids prevented the cerebral manifestations of ALF (brain swelling, herniation, death). Further investigation of SRBAL therapy in a clinical setting is warranted.

Early bedside detection of ischemia and rejection in liver transplants by microdialysis

This study was performed to explore whether lactate, pyruvate, glucose, and glycerol levels sampled via microdialysis catheters in the transplanted liver could be used to detect ischemia and/or rejection. The metabolites were measured at the bedside every 1 to 2 hours after the operation for a median of 10 days. Twelve grafts with biopsy‐proven rejection and 9 grafts with ischemia were compared to a reference group of 39 grafts with uneventful courses. The median lactate level was significantly higher in both the ischemia group [5.8 mM (interquartile range = 4.0‐11.1 mM)] and the rejection group [2.1 mM (interquartile range = 1.9‐2.4 mM)] versus the reference group [1.5 mM (interquartile range = 1.1‐1.9 mM), P < 0.001 for both]. The median pyruvate level was significantly increased only in the rejection group [185 μM (interquartile range = 155‐206 μM)] versus the reference group [124 μM (interquartile range = 102‐150 μM), P < 0.001], whereas the median lactate/pyruvate ratio and the median glycerol level were increased only in the ischemia group [66.1 (interquartile range = 23.9‐156.7) and 138 μM (interquartile range = 26‐260 μM)] versus the reference group [11.8 (interquartile range = 10.6‐13.6), P < 0.001, and 9 μM (interquartile range = 9‐24 μM), P = 0.002]. Ischemia was detected with 100% sensitivity and greater than 90% specificity when a positive test was repeated after 1 hour. In 3 cases of hepatic artery thrombosis, ischemia was detected despite normal blood lactate levels. Consecutive pathological measurements for 6 hours were used to diagnose rejection with greater than 80% sensitivity and specificity at a median of 4 days before the activity of alanine aminotransferase, the concentration of bilirubin in serum, or both increased. In conclusion, bedside measurements of intrahepatic lactate and pyruvate levels were used to detect ischemia and rejection earlier than current standard methods could. Discrimination from an uneventful patient course was achieved. Consequently, intrahepatic graft monitoring with microdialysis may lead to the earlier initiation of graft‐saving treatment. Liver Transpl, 2012.

Inflammatory markers sampled by microdialysis catheters distinguish rejection from ischemia in liver grafts

Rejection and ischemia are serious complications after liver transplantation. Early detection is mandatory, but specific markers are largely missing, particularly for rejection. The objective of this study was to explore the ability of microdialysis catheters inserted in liver grafts to detect and discriminate rejection and ischemia through postoperative measurements of inflammatory mediators. Microdialysis catheters with a 100‐kDa pore size were inserted into 73 transplants after reperfusion. After the studys completion, complement activation product 5a (C5a), C‐X‐C motif chemokine 8 (CXCL8), CXCL10, interleukin‐1 (IL‐1) receptor antagonist, IL‐6, IL‐10, and macrophage inflammatory protein 1β were analyzed en bloc in all grafts with biopsy‐confirmed rejection (n = 12), in grafts with vascular occlusion/ischemia (n = 4), and in reference grafts with a normal postoperative course of circulating transaminase and bilirubin levels (n = 17). The inflammatory mediators were elevated immediately after graft reperfusion and decreased toward low, stable values during the first 24 hours in nonischemic grafts. In grafts suffering from rejection, CXCL10 increased significantly (P = 0.008 versus the reference group and P = 0.002 versus the ischemia group) 2 to 5 days before increases in circulating alanine aminotransferase and bilirubin levels. The area under the receiver operating characteristic curve was 0.81. Grafts with ischemia displayed increased levels of C5a (P = 0.002 versus the reference group and P = 0.008 versus the rejection group). The area under the curve was 0.99. IL‐6 and CXCL8 increased with both ischemia and rejection. In conclusion, CXCL10 and C5a were found to be selective markers for rejection and ischemia, respectively. Liver Transpl, 2012.

Clinical experience with microdialysis catheters in pediatric liver transplants.

Ischemic vascular complications and rejection occur more frequently with pediatric liver transplants versus adult liver transplants. Using intrahepatic microdialysis catheters, we measured lactate, pyruvate, glucose, and glycerol values at the bedside for a median of 10 days in 20 pediatric liver grafts. Ischemia (n = 6), which was defined as a lactate level > 3.0 mM and a lactate/pyruvate ratio > 20, was detected without a measurable time delay with 100% sensitivity and 86% specificity. Rejection (n = 8), which was defined as a lactate level > 2.0 mM and a lactate/pyruvate ratio < 20 lasting for 6 or more hours, was detected with 88% sensitivity and 45% specificity. With additional clinical criteria, the specificity was 83% without a decrease in the sensitivity. Rejection was detected at a median of 4 days (range = 1‐7 days) before alanine aminotransferase increased (n = 5, P = 0.11), at a median of 4 days (range = 2‐9 days) before total bilirubin increased 25% or more (n = 7, P = 0.04), and at a median of 6 days (range = 4‐11 days) before biopsy was performed (n = 8, P = 0.05). In conclusion, microdialysis catheters can be used to detect episodes of ischemia and rejection before current standard methods in pediatric liver transplants with clinically acceptable levels of sensitivity and specificity. The catheters were well tolerated by the children, and no major complications related to the catheters were observed. Liver Transpl 19:305–314, 2013.

Hepatic and Abdominal Carbon Dioxide Measurements Detect and Distinguish Hepatic Artery Occlusion and Portal Vein Occlusion in Pigs

Hepatic artery (HA) occlusion and portal vein (PV) occlusion are the most common vascular complications after liver transplantation with an impact on mortality and retransplantation rates. The detection of severe hypoperfusion may be delayed with currently available diagnostic tools. Hypoperfusion and anaerobically produced lactic acid lead to increases in tissue carbon dioxide. We investigated whether the continuous assessment of the intrahepatic and intra‐abdominal partial pressure of carbon dioxide (PCO2) could be used to detect and distinguish HA and PV occlusions in real time. In 13 pigs, the HA and the PV were fully occluded (n = 7) or gradually occluded (n = 6). PCO2 was monitored intrahepatically and between loops of small intestine. The hepatic and intestinal metabolism was assessed with microdialysis and PV as well as hepatic vein blood samples, and the results were compared to clinical parameters for the systemic circulation and blood gas analysis. Total HA occlusion led to significant increases in hepatic PCO2 and lactate, and this was accompanied by significant decreases in the partial pressure of oxygen and glucose. PV occlusion induced a significant increase in intestinal PCO2 (but not hepatic PCO2) along with significant increases in intestinal lactate and glycerol. Gradual HA occlusion and PV occlusion caused steady hepatic and intestinal PCO2 increases, respectively. Systemic clinical parameters such as the blood pressure, heart rate, and cardiac output were affected only by PV occlusion. In conclusion, even gradual HA occlusion affects liver metabolism and can be reliably identified with hepatic PCO2 measurements. Intestinal PCO2 increases only during PV occlusion. A combination of hepatic and intestinal PCO2 measurements can reliably diagnose the affected vessel and depict the severity of the occlusion, and this may emerge as a potential real‐time clinical monitoring tool for the postoperative course of liver transplantation and enable early interventions. Liver Transpl, 2012.

Continuous molecular adsorbent recirculating system treatment in 69 patients listed for liver transplantation

Abstract Objective. The molecular adsorbent recirculating system (MARS) is used to purify blood from albumin-bound toxins in patients with liver failure. However, the application of MARS has not demonstrated improved survival in randomized clinical trials and the clinical utility has not been finally established. In our department, the use of MARS is now restricted to the most critically ill patients with acute or acute on chronic liver failure. Material and methods. Since 2005, we have treated 69 patients (30 males/39 females with median age of 49 years ranging from 1 months to 70 years) listed for liver transplantation (LT) with MARS. Median model of end-stage liver disease score in patients older than 12 years of age (n = 56) was 33 (interquartile range 26–39). The flow rate was 35–40 mL/kg/h and treatment kits were changed every 8–12 h. The patients were treated for a median of 27 h (range 1–144 h). Results. Fifty-six patients (81%) were transplanted. Nine died before they could be transplanted, and four patients recovered without transplantation. Forty-six (82%) of the transplanted patients were alive 30 days after transplantation. Ammonium decreased modestly from a median of 148 to 124 µM (p = 0.03) during MARS treatment. We detected worsening of coagulopathy with significant decreases in platelet count and fibrinogen concentrations, and increase in International Normalized Ratio. Phosphate and magnesium decreased significantly during MARS treatment. Conclusion. Continuous MARS therapy may bridge liver failure patients to LT under close observation and treatment of coagulopathy and electrolyte disturbances.

Low Incidence of Hyperfibrinolysis and Thromboembolism in 195 Primary Liver Transplantations Transfused with Solvent/Detergent Treated Plasma

Background Liver transplantation regularly requires transfusion of red blood cells (RBCs), plasma, and platelets. Compared to fresh frozen plasma (FFP) from single blood donors, solvent/detergent-treated plasma (SD-plasma) pooled from several hundred blood donors has advantages with respect to pathogen reduction, standardized content of plasma proteins, and significantly reduced risk of transfusion related lung injury and allergic/immunologic adverse reactions. However, SD-plasma has been suspected to increase the incidence of hyperfibrinolysis and thromboembolic events. Study Design and Methods We investigated the transfusion practices, hyperfibrinolysis parameters, and thrombosis outcomes in 195 consecutive adult primary liver transplants in our center using SD-plasma (Octaplas) as the exclusive source of plasma. Results Perioperatively, median (interquartile range) 4 (1 to 9) RBC-units, 10 (4 to 18) plasma-bags, and 0 (0 to 2) platelet-units were transfused. Hyperfibrinolysis defined as LY30 ≤ 7.5% was detected in 12/138 thrombelastography-monitored patients (9%). These patients received significantly more RBCs, plasma, and platelets than did patients without hyperfibrinolysis. Thrombotic graft complications were observed in three patients (2%). Pulmonary embolism was not observed in any patient. Conclusion SD-plasma is a safe plasma product for liver transplant recipients, and the incidences of hyperfibrinolysis and thromboembolic events are not significantly different from those seen in centers using FFP.

Severe hemolytic transfusion reaction due to anti-A1 following allogeneic stem cell transplantation with minor ABO incompatibility

Blood components should be compatible both with the recipient and the donor in the ABO incompatible allogeneic stem cell transplantation setting. A patient with blood type A2 received peripheral blood stem cells from a blood type O donor. The patient was in critical condition due to treatment-related toxicity. He had acquired anti-A1 that was unfortunately overlooked. Following transfusion of A1 red blood cells in error, he developed a severe hemolytic transfusion reaction. Anti-A1 is rarely clinically significant. We discuss the role of passenger lymphocytes in development of the anti-A1, and stress the importance of investigating unusual/atypical reactions in blood typing.

Outcomes in pancreas transplantation with exocrine drainage through a duodenoduodenostomy versus duodenojejunostomy

Until recently, pancreas transplantation has mostly been performed with exocrine drainage via duodenojejunostomy (DJ). Since 2012, DJ was substituted with duodenoduodenostomy (DD) in our hospital, allowing endoscopic access for biopsies. This study assessed safety profiles with DD versus DJ procedures and clinical outcomes with the DD technique in pancreas transplantation. DD patients (n = 117; 62 simultaneous pancreas–kidney [SPKDD] and 55 pancreas transplantation alone [PTADD] with median follow‐up 2.2 years) were compared with DJ patients (n = 179; 167 SPKDJ and 12 PTADJ) transplanted in the period 1998–2012 (pre‐DD era). Postoperative bleeding and pancreas graft vein thrombosis requiring relaparotomy occurred in 17% and 9% of DD patients versus 10% (p = 0.077) and 6% (p = 0.21) in DJ patients, respectively. Pancreas graft rejection rates were still higher in PTADD patients versus SPKDD patients (p = 0.003). Hazard ratio (HR) for graft loss was 2.25 (95% CI 1.00, 5.05; p = 0.049) in PTADD versus SPKDD recipients. In conclusion, compared with the DJ procedure, the DD procedure did not reduce postoperative surgical complications requiring relaparatomy or improve clinical outcomes after pancreas transplantation despite serial pancreatic biopsies for rejection surveillance. It remains to be seen whether better rejection monitoring in DD patients translates into improved long‐term pancreas graft survival.