Impact of a left-lobe graft without modulation of portal flow in adult-to-adult living donor liver transplantation

Small-for-size graft, small-for-size syndrome and inflow modulation in living donor liver transplantation

The extended application of living donor liver transplantation (LDLT) has revealed the problem of graft size mismatching called "small-for-size syndrome (SFSS)." The initial trials to resolve this problem involved increasing the procured graft size, from left to right, and even extending to include a right lobe graft. Clinical cases of living right lobe donations have been reported since then, drawing attention to the risks of increasing the liver volume procured from a living donor. However, not only other modes of increasing graft volume (GV) such as auxiliary or dual liver transplantation, but also control of the increased portal pressure caused by a small-for-size graft (SFSG), such as a porto-systemic shunt or splenectomy and optimal outflow reconstruction, have been trialed with some positive results. To establish an effective strategy for transplanting SFSG and preventing SFSS, it is essential to have precise knowledge and tactics to evaluate graft quality and GV, when performing these LDLTs with portal pressure control and good venous outflow. Thus, we reviewed the updated literature on the pathogenesis of and strategies for using SFSG.

Risk Factors for Intractable Ascites After Adult-to-Adult Living Donor Liver Transplantation Using Left Lobe. Transplant Direct. 2017;3:e138. [PMID: 28361122 PMCID: PMC5367755 DOI: 10.1097/txd.0000000000000652]

Background

Intractable ascites is one of the causes of graft loss after adult-to-adult living donor liver transplantation (LDLT) using a small graft. Identification of factors associated with increasing posttransplant ascites has important implications for prevention and treatment.

Methods

All 59 consecutive adult patients who underwent left lobe LDLT without portal inflow modulation between October 2002 and February 2016 were prospectively enrolled. Factors associated with the average daily amount of ascites for 2 weeks after LDLT were assessed.

Results

The median daily amount of ascites during the 2 weeks was 1052 mL (range, 52-3480 mL). Although 16 of the 59 patients developed intractable ascites, exceeding 1500 mL daily (massive ascites group), the remaining 43 patients produced less than 1500 mL of ascites daily (nonmassive ascites group). The presence of pretransplant ascites (P = 0.001), albumin (P = 0.011), albumin/globulin ratio (P = 0.026), cold ischemia time (P = 0.004), operation time (P = 0.022), and pretransplant portal vein pressure (PVP) (P = 0.047) differed significantly between the 2 groups. Neither posttransplant PVP nor portal vein flow differed between the 2 groups. The variables associated with intractable ascites that remained significant after logistic regression analysis were pretransplant PVP (P = 0.047) and cold ischemia time (P = 0.049). After appropriate fluid resuscitation for intractable ascites, 58 (98%) of the 59 recipients were discharged from hospital after removal of the indwelling drains.

Conclusions

It is important to shorten the scold ischemia time to reduce massive ascites after LDLT. Pretransplant portal hypertension is more closely associated with ascites production than posttransplant hemodynamic status.

Should temporary extracorporeal continuous portal diversion replace meso/porta-caval shunts in “small-for-size” syndrome in porcine hepatectomy?

AIM: To investigate the feasibility of temporary extracorporeal continuous porta-caval diversion (ECPD) to relieve portal hyperperfusion in “small-for-size” syndrome following massive hepatectomy in pigs.

METHODS: Fourteen pigs underwent 85%-90% liver resection and were then randomly divided into the control group (n = 7) and diversion group (n = 7). In the diversion group, portal venous blood was aspirated through the portal catheter and into a tube connected to a centrifugal pump. After filtration, the blood was returned to the pig through a double-lumen catheter inserted into the internal jugular or subclavian vein. With the conversion pump, portal venous inflow was partially diverted to the inferior vena cava through a catheter inserted via the gastroduodenal vein at 100-130 mL/min. Portal hemodynamics, injury, and regeneration in the liver remnant were compared between the two groups.

RESULTS: Compared to the control group, porta-caval diversion via ECPD significantly mitigated excessive portal venous flow and portal vein pressure (PVP); the portal vein flow (PVF), hepatic artery flow (HAF), and PVP in the two groups were not significantly different at baseline; however, the PVF (431.8 ± 36.6 vs 238.8 ± 29.3, P < 0.01; 210.3 ± 23.4 vs 122.3 ± 20.6, P < 0.01) and PVP (13.8 ± 2.6 vs 8.7 ± 1.4, P < 0.01; 15.6 ± 2.1 vs 10.1 ± 1.3, P < 0.05) in the control group were significantly higher than those in the diversion group, respectively. The HAF in the control group was significantly lower than that in the diversion group at 2 h and 48 h post hepatectomy, and ECPD significantly attenuated injury to the sinusoidal lining and hepatocytes, increased the regeneration index of the liver remnant, and relieved damage that the liver remnant suffered due to endotoxin and bacterial translocation.

CONCLUSION: ECPD, which can dynamically modulate portal inflow, can reduce injury to the liver remnant and facilitate liver regeneration, and therefore should replace permanent meso/porta-caval shunts in “small-for-size” syndrome.

Evaluation of esophagogastric varices after adult-to-adult living donor liver transplantation using a left lobe graft

BACKGROUND

There is little information on whether living donor liver transplantation (LDLT) reduces the supply of blood to esophagogastric varices. The aim of the present study was to assess the effects of LDLT on esophagogastric varices using both endoscopy and transendoscopic microvascular Doppler sonography (EMDS).

PATIENTS AND METHODS

16 LDLT recipients were enrolled in the present study. Esophagogastric varices were assessed by endoscopy before and after LDLT. Direct measurement of variceal blood velocity was performed using EMDS in 12 of the 16 patients, and portal vein pressure before and after graft implantation was measured in 10 of them.

RESULTS

The median interval between LDLT and endoscopic examination was 129 days (range 20-624). Endoscopy demonstrated improvement of esophageal varices in 15 patients and of gastric varices in 4 of 5 patients assessed. The mean blood flow velocity in esophageal varices after LDLT was significantly lower than that before LDLT (8.8 ± 3.6 vs. 0.9 ± 1.2 cm/s, p < 0.001). The mean portal vein pressure did not decrease significantly after LDLT in comparison with that before LDLT (from 25.2 ± 5.2 to 23.1 ± 3.6 mm Hg, p = 0.22).

CONCLUSION

Although portal vein pressure does not decrease immediately after left lobe LDLT, esophagogastric varices are ameliorated after a few months, and variceal blood flow velocity is reduced in almost all patients.

Small-for-size syndrome in living-donor liver transplantation using a left lobe graft. Surg Today. 2015;45:663-671. [PMID: 24894564 DOI: 10.1007/s00595-014-0945-x]

In living-donor liver transplantation with a left lobe graft, which can reduce the burden on the donor compared to right lobe graft, the main problem is small-for-size (SFS) syndrome. SFS syndrome is a multifactorial disease that includes aspects related to the graft size, graft quality, recipient factors and even technical issues. The main pathophysiology of SFS syndrome is the sinusoidal microcirculatory disturbance induced by shear stress, which is caused by excessive portal inflow into the smaller graft. The donor age, the presence of steatosis of the graft and a poor recipient status are all risk factors for SFS syndrome. To resolve SFS syndrome, portal inflow modulation, splenectomy, splenic artery modulation and outflow modulation have been developed. It is important to establish strict criteria for managing SFS syndrome. Using pharmacological interventions and/or therapeutic approaches that promote liver regeneration could increase the adequate outcomes in SFS liver transplantation. Left lobe liver transplantation could be adopted in Western countries to help resolve the organ shortage.

Adult-to-adult living donor liver transplantation for acute liver failure in China

AIM: To investigate the long-term outcome of recipients and donors of adult-to-adult living-donor liver transplantation (AALDLT) for acute liver failure (ALF).

METHODS: Between January 2005 and March 2010, 170 living donor liver transplantations were performed at West China Hospital of Sichuan University. All living liver donor was voluntary and provided informed consent. Twenty ALF patients underwent AALDLT for rapid deterioration of liver function. ALF was defined based on the criteria of the American Association for the Study of Liver Diseases, including evidence of coagulation abnormality [international normalized ratio (INR) ≥ 1.5] and degree of mental alteration without pre-existing cirrhosis and with an illness of < 26 wk duration. We reviewed the clinical indications, operative procedure and prognosis of AALDTL performed on patients with ALF and corresponding living donors. The potential factors of recipient with ALF and corresponding donor outcome were respectively investigated using multivariate analysis. Survival rates after operation were analyzed using the Kaplan-Meier method. Receiver operator characteristic (ROC) curve analysis was undertaken to identify the threshold of potential risk factors.

RESULTS: The causes of ALF were hepatitis B (n = 18), drug-induced (n = 1) and indeterminate (n = 1). The score of the model for end-stage liver disease was 37.1 ± 8.6, and the waiting duration of recipients was 5 ± 4 d. The graft types included right lobe (n = 17) and dual graft (n = 3). The mean graft weight was 623.3 ± 111.3 g, which corresponded to graft-to-recipient weight ratio of 0.95% ± 0.14%. The segment Vor VIII hepatic vein was reconstructed in 11 right-lobe grafts. The 1-year and 3-year recipient’s survival and graft survival rates were 65% (13 of 20). Postoperative results of total bilirubin, INR and creatinine showed obvious improvements in the survived patients. However, the creatinine level of the deaths was increased postoperatively and became more aggravated compared with the level of the survived recipients. Multivariate analysis showed that waiting duration was independently correlated with increased mortality (P = 0.014). Furthermore, ROC curve revealed the cut-off value of waiting time was 5 d (P = 0.011, area under the curve = 0.791) for determining the mortality. The short-term creatinine level with different recipient’s waiting duration was described. The recipients with waiting duration ≥ 5 d showed the worse renal function and higher mortality than those with waiting duration < 5 d (66.7% vs 9.1%, P = 0.017). In addition, all donors had no residual morbidity. Furthermore, univariate analysis did not show that short assessment time induced the high morbidity (P = 0.573).

CONCLUSION: Timely AALDLT for patients with ALF greatly improves the recipient survival. However, further systemic review is needed to investigate the optimal treatment strategy for ALF.

[Small-for-size: experimental findings for liver surgery]

The characteristics of the hepatic macrocirculation, i.e., the parallel portal-venous and arterial blood supply, is of utmost relevance for liver surgery. With extended hepatectomy or transplantation of a reduced-size liver the remaining or transplanted liver tissue is overperfused because the liver fails to regulate the portal-venous inflow. This portal hyperperfusion is responsible for the initiation of liver cell proliferation but represents at the same time one of the substantial events in the pathogenesis of the small-for-size syndrome. Portal-venous hyperperfusion, the so-called hepatic arterial buffer response, which describes the semi-reciprocal relationship between the portal-venous and hepatic arterial blood flows, leads to an arterial hypoperfusion of the small-for-size liver. In this article experimental and clinical data are discussed which underline the high but so far overseen relevance of this arterial underperfusion in the development of a small-for-size syndrome.

Current concept of small-for-size grafts in living donor liver transplantation

The extended application of living donor liver transplantation (LDLT) has revealed the problem of graft size mismatching called "small-for-size (SFS) graft syndrome." The initial trials to resolve this problem involved increasing the procured graft size, from left to right, and even extension to include a right lobe graft. Clinical cases of living right lobe donations have been reported since then, drawing attention to the risks of increasing the liver volume procured from a living donor. However, not only other modes of increasing graft volume such as auxiliary or dual liver transplantation, but also control of the increased portal pressure caused by an SFS graft, such as a portosystemic shunt or splenectomy, have been trialed with some positive results. To establish an effective strategy for transplanting SFS grafts and preventing SFS graft syndrome, it is essential to have precise knowledge and tactics to evaluate graft quality and graft volume, when performing these LDLTs with portal pressure control. We reviewed the updated literature on the pathogenesis of and strategies for using SFS grafts.