Differences in portal hemodynamics between whole liver transplantation and living donor liver transplantation

Pediatric living donor left lateral segment liver transplantation for biliary atresia: Doppler ultrasound findings in early postoperative period

PURPOSE

To analyze hepatic hemodynamic parameters detected by Doppler ultrasound (DU) of uncomplicated children with biliary atresia who underwent left lateral segment living donor liver transplantation (LLS-LDLT), explore its normal change trend over time and determine the normal reference interval.

METHODS

We retrospectively involved the data from 227 biliary atresia patients (100 Males,127 Females). Hemodynamic parameters include peak systolic velocity (PSV), end-diastolic velocity (EDV), resistivity index (RI), and pulsation index (PI) of the hepatic artery (HA), portal vein velocity (PVV), portal vein flow (PVF) and hepatic vein velocity (HVV) during intra-operative and on the 1st, 3rd, 5th and 7th day after operation were collected. Repeated measures analysis of the variance and Friedman test were used to analyze the changing trend of hemodynamic parameters over time in the first week after the operation.

RESULTS

PSV_HA and EDV_HA showed a similar changing tendency at one week after surgery, with an overall decrease-rise trend; RI_HA and PI_HA also changed similarly with an overall rise-decrease trend. The HVV and PVV at surgery were lower than at all time points after surgery. As for PVF, the value of POD5 was the highest and then decreased. Additionally, this study provided the normal reference interval of hemodynamic parameters for LLS-LDLT patients, which were PSV_HA: 18.4-98.3 cm/s, EDV_HA: 0-43.3 cm/s, RI_HA: 0.41-1.0, PI_HA: 0.51-2.0, PVV: 19.0-83.7 cm/s, HVV: 19.4-68.0 cm/s, and PVF:99.5-500.0 ml/min/100 g at intraoperation. Within the first postoperative week: PSV_HA: 21.0-97.7 cm/s, EDV_HA: 0-32.7 cm/s, RI_HA: 0.47-1.0, PI_HA: 0.62-2.0, PVV: 23.0-92.0 cm/s, HVV: 19.7-86.0 cm/s, and PVF: 100.0-513.0 ml/min/100 g.

CONCLUSION

The hepatic hemodynamic of post-transplanted children detected by DU had specific changing trends and normal ranges, which provides valuable reference values for ultrasonologists and pediatric transplant clinicians.

Impact of imbalanced graft-to-spleen volume ratio on outcomes following living donor liver transplantation in an era when simultaneous splenectomy is not typically indicated

The impact of an imbalanced graft-to-spleen volume ratio (GSVR) on posttransplant outcomes other than postreperfusion portal hypertension remains unknown. The importance of GSVR might vary according to whether simultaneous splenectomy (SPX) is performed. This retrospective study divided 349 living donor liver transplantation (LDLT) recipients from 2006 to 2017 into 2 groups: low GSVR (≤0.70 g/mL) and normal GSVR (>0.70 g/mL). The cutoff value of GSVR was set based on the first quartile of the distributed data. Graft survival and associations with various clinical factors were investigated between the groups according to whether SPX was performed. Low GSVR did not affect outcomes when SPX was performed. In contrast, it was associated with an increased incidence of early graft loss (EGL) and poor graft survival by presenting posttransplant thrombocytopenia, cholestasis, coagulopathy, and massive ascites when the spleen was preserved. Among patients with a preserved spleen, the multivariable analysis results revealed that older donor age and low GSVR were independent risk factors for graft loss. In conclusion, low GSVR was an independent predictor of graft loss after LDLT when the spleen was preserved. Preserved spleen with extremely low GSVR may be related to persistent hypersplenism, impaired graft function, and consequent EGL.

A Novel Predictor of Posttransplant Portal Hypertension in Adult-To-Adult Living Donor Liver Transplantation: Increased Estimated Spleen/Graft Volume Ratio

BACKGROUND

In adult living donor liver transplantation (ALDLT), graft-to-recipient weight ratio of less than 0.8 is incomplete for predicting portal hypertension (>20 mm Hg) after reperfusion. We aimed to identify preoperative factors contributing to portal venous pressure (PVP) after reperfusion and to predict portal hypertension, focusing on spleen volume-to-graft volume ratio (SVGVR).

METHODS

In 73 recipients with ALDLT between 2002 and 2013, first we analyzed survival according to PVP of 20 mm Hg as the threshold, evaluating the efficacy of splenectomy. Second, we evaluated various preoperative factors contributing to portal hypertension after reperfusion.

RESULTS

All of the recipients with PVP greater than 20 mm Hg (n = 19) underwent PVP modulation by splenectomy, and their overall survival was favorable compared with 54 recipients who did not need splenectomy (PVP ≤ 20 mm Hg). Graft-to-recipient weight ratio had no correlation with PVP.Multivariate analysis revealed that estimated graft and spleen volume were significant factors contributing to PVP after reperfusion (P < 0.0001 and P < 0.0001, respectively). Furthermore, estimated SVGVR showed a significant negative correlation to PVP after reperfusion (R = 0.652), and the best cutoff value for portal hypertension was 0.95.

CONCLUSIONS

In ALDLT, preoperative assessment of SVGVR is a good predictor of portal hypertension after reperfusion can be used to indicate the need for splenectomy before reperfusion.

Portosystemic collaterals in living donor liver transplantation: What is all the fuss about?

Portosystemic collaterals are a common finding in patients with cirrhosis undergoing liver transplantation. Recently, there has been a renewed interest regarding their significance in the setting of living donor liver transplantation (LDLT) due to concerns of graft hypoperfusion or hyperperfusion and its impact on early posttransplant outcomes. Presence of these collaterals has greater significance in the LDLT setting when compared with the deceased donor liver transplantation setting as dictated by the difference in the physiology of partial liver grafts. We discuss current thinking of portal flow dynamics and the techniques for dealing with this clinical problem. Liver Transplantation 23 537-544 2017 AASLD.

Role of Doppler Ultrasonography in Defining Normal and Abnormal Graft Hemodynamics After Living-Donor Liver Transplant

OBJECTIVES

Our aim was to investigate the early changes that occur after graft perfusion in living-donor liver transplant by Doppler ultrasonography.

MATERIALS AND METHODS

We prospectively evaluated liver grafts of 30 patients who underwent living-donor liver transplant during an 18-month period and who were followed for 1 year postoperatively. The hepatic artery peak systolic velocity, resistivity index, portal vein velocity, portal vein anastomotic velocity ratio, and hepatic vein pattern were compared after excluding patients who developed vascular complications and acute rejection episodes.

RESULTS

We observed intraoperative increases in the mean hepatic artery peak systolic velocity (96.3 ± 65 cm/s), the resistivity index (0.78 ± 0.091), and the portal vein velocity (99.6 ± 48 cm/s), which started to normalize after 2 weeks. In comparing the mean portal vein velocity, portal vein anastomotic velocity ratio, hepatic artery peak systolic velocity, and resistivity index after excluding 5 patients who developed vascular complications, we observed overall significance levels of P < .001, P = .039, P < .001, and P = .040. After we excluded 9 patients who developed acute rejection, our comparison of the portal vein velocity, hepatic artery peak systolic velocity, and resistivity index showed overall significance (P < .001, P < .001, and P = .043).

CONCLUSIONS

Early and transient increases in portal vein velocity, anastomotic velocity ratio, hepatic artery peak systolic velocity, and resistivity index are common after living-donor liver transplant, with significant declines in the first 2 weeks posttransplant.

Doppler ultrasonography in living donor liver transplantation recipients: Intra- and post-operative vascular complications

Living-donor liver transplantation has provided a solution to the severe lack of cadaver grafts for the replacement of liver afflicted with end-stage cirrhosis, fulminant disease, or inborn errors of metabolism. Vascular complications remain the most serious complications and a common cause for graft failure after hepatic transplantation. Doppler ultrasound remains the primary radiological imaging modality for the diagnosis of such complications. This article presents a brief review of intra- and post-operative living donor liver transplantation anatomy and a synopsis of the role of ultrasonography and color Doppler in evaluating the graft vascular haemodynamics both during surgery and post-operatively in accurately defining the early vascular complications. Intra-operative ultrasonography of the liver graft provides the surgeon with useful real-time diagnostic and staging information that may result in an alteration in the planned surgical approach and corrections of surgical complications during the procedure of vascular anastomoses. The relevant intra-operative anatomy and the spectrum of normal and abnormal findings are described. Ultrasonography and color Doppler also provides the clinicians and surgeons early post-operative potential developmental complications that may occur during hospital stay. Early detection and thus early problem solving can make the difference between graft survival and failure.

Child-to-Adult Liver Transplantation With Donation After Cardiac Death Donors: Three Case Reports

Development of organ transplantation is restricted by the discrepancy between the lack of donors and increasing number of patients. The outcome of pediatric donors transplanted into adult recipients especially with donation after circulatory death (DCD) pattern has not been well studied. The aim of this paper is to describe our experience of 3 successful DCD donor child-to-adult liver transplantations lately. Three DCD donors were separately 7, 5, and 8 years old. The ratio between donor graft weight and recipient body weight was 1.42%, 1.00%, and 1.33%, respectively. Ratio between the volume of donor liver and the expected liver volume was 0.65, 0.46, and 0.60. Splenectomy was undertaken for the second recipient according to the portal vein pressure (PVP) which was observed during the operation. Two out of 3 of the recipients suffered with acute kidney injury and got recovered after renal replacement therapy. The first recipient also went through early allograft dysfunction and upper gastrointestinal bleeding. The hospital course of the third recipient was uneventful. After 1 year of follow-up visit, the first and second recipients maintain good quality of life and liver function. The third patient was followed up for 5 months until now and recovered well. DCD child-to-adult liver transplantation should only be used for comparatively matched donor and recipient. PVP should be monitored during the operation. The short-term efficacy is good, but long-term follow-up and clinical study with large sample evaluation are still needed.

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.

The causes, risk factors, and outcomes of early relaparotomy after living-donor liver transplantation

BACKGROUND

Although early relaparotomy of the recipient after living-donor liver transplantation (LDLT) is a significant event, its causes, risk factors, and outcomes are still unclear.

METHODS

A retrospective analysis of 284 cases of adult-to-adult LDLT was performed.

RESULTS

The incidence of early relaparotomy of the recipient was 9.2% (n=26). The reasons for relaparotomy were divided into three groups: postoperative bleeding (n=11, 42.3%), insufficient portal venous flow (n=5, 19.2%), and other (n=10, 38.5%). The 6-month graft survival rates of patients in the early laparotomy and nonlaparotomy groups were 61.5% and 88.4%, respectively (P<0.0001). Patients with postoperative bleeding experienced a significantly higher mortality rate (54.6%) than those with other reasons for early relaparotomy (13.3%; P=0.0231). Multivariate analysis showed that a model for end-stage liver disease score of greater than 20 (odds ratio [OR], 9.06; P=0.0434) and an operative blood loss of greater than 15 L (OR, 9.06; P=0.0434) were significant risk factors for graft loss after early relaparotomy. In patients with patent major shunt vessels (>1 cm in diameter, n=31), portal venous flow of less than 1.0 L/min at the end of surgery was a significant risk factor for early relaparotomy to ligate the remaining shunt vessels (OR, 50.5; P=0.0188).

CONCLUSIONS

Early relaparotomy of the recipient is significantly associated with poor graft survival after LDLT. Massive intraoperative blood loss and high model for end-stage liver disease score were associated with poor graft survival in the relaparotomy group.

Human taurine metabolism: fluxes and fractional extraction rates of the gut, liver, and kidneys

Taurine is involved in numerous biological processes. However, taurine plasma level decreases in response to pathological conditions, suggesting an increased need. Knowledge on human taurine metabolism is scarce and only described by arterial-venous differences across a single organ. Here we present taurine organ fluxes using arterial-venous concentration differences combined with blood flow measurements across the 3 major organ systems involved in human taurine metabolism in patients undergoing hepatic surgery. In these patients, we collected blood from an arterial line, portal vein, hepatic vein, and renal vein, and determined blood flow of the hepatic artery, portal vein, and renal vein using Doppler ultrasound. Plasma taurine was determined by high-performance liquid chromatography, and net organ fluxes and fractional extraction rates were calculated. Seventeen patients were studied. No differences were found between taurine concentrations in arterial, portal venous, hepatic venous, and renal venous plasma. The only significant finding was a release of taurine by the portally drained viscera (P = .04). Our data show a net release of taurine by the gut. This probably is explained by the enterohepatic cycle of taurine. Future studies on human taurine metabolism are required to determine whether taurine is an essential aminosulfonic acid during pathological conditions and whether it should therefore be supplemented.