Postoperative complications in patients with portal vein thrombosis after liver transplantation: Evaluation with Doppler ultrasonography

Thrombotic complications post liver transplantation: Etiology and management

Liver transplantation (LT) is the life saving therapeutic option for patients with acute and chronic end stage liver disease. This is a routine procedure with excellent outcomes in terms of patient survival and quality of life post LT. Orthotopic LT (OLT) patients require a critical care as they are prone to variety of post-operative vascular, cardiovascular, biliary, pulmonary and abdominal complications. Thrombotic complications (both arterial and venous) are not uncommon post liver transplant surgery. Such vascular problems lead to increased morbidity and mortality in both donor and graft recipient. Although thromboprophylaxis is recommended in general surgery patients, no such standards exist for liver transplant patients. Drastic advancements of surgical and anesthetic procedures have improvised survival rates of patients post OLT. Despite these, haemostatic imbalance leading to thrombotic events post OLT cause significant graft loss and morbidity and even lead to patient’s death. Thus it is extremely important to understand pathophysiology of thrombosis in LT patients and shorten the timing of its diagnosis to avoid morbidity and mortality in both donor and graft recipient. Present review summarizes the current knowledge of vascular complications associated with LT to highlight their impact on short and long-term morbidity and mortality post LT. Also, present report discusses the lacunae existing in the literature regarding the risk factors leading to arterial and venous thrombosis in LT patients.

The Management of Portal Vein Thrombosis after Adult Liver Transplantation: A Case Series and Review of the Literature

Background: Portal vein thrombosis (PVT) after adult liver transplantation (LT) is a rare but serious complication with no consensus on the ideal treatment. We report a case series and a comprehensive review of the literature on PVT after LT to discuss the therapeutic options. Methods: The clinical data of 360 adult patients (≥18 years of age) who underwent LT from January 2017 to January 2020 were reviewed, and a comprehensive search of PubMed and Web of Science was conducted. Patients diagnosed with PVT after LT were identified, and relevant risk factors and therapies were analyzed. Results: Among the 360 patients, 7 (1.94%) developed PVT after LT. Onset of PVT within one week after LT was found in six patients (85.71%). Four of the seven patients with PVT received systemic anticoagulation (low molecular weight heparin and warfarin) therapy. Minimally invasive interventional therapies combined with systemic anticoagulation (heparin and warfarin) were applied for three patients, two of whom died because of severe abdominal hemorrhage and liver failure. Of the 33 cases reported in the literature, minimally invasive interventional therapy combined with systematic anticoagulation or sclerotherapy were the most-used methods (20/33). Systemic anticoagulation was administered to four patients, and surgical operation (thrombectomy; portosystemic shunt and retransplantation) was performed for nine patients. Among these 33 patients, 4 eventually died. Conclusions: Interventional therapy combined with systemic anticoagulation is a good choice for the management of PVT after LT, and in our experience, systemic anticoagulation alone can also have a positive effect for early PVT patients.

Incidence of Bleeding and Thrombosis in Patients with Liver Disease

Historically, liver disease has been associated with a bleeding tendency. Global hemostatic assays have demonstrated that hemostasis is overall rebalanced, in both acute liver failure and chronic liver disease. It is now recognized that many bleeding events in chronic liver disease are mediated by portal hypertension rather than an underlying hemostatic defect. This is acknowledged in recent guidelines, which recommend against coagulation testing prior to low risk procedures in this patient group, with avoidance also of attempts at correction of prolonged coagulation times. Over time, the incidence of bleeding events has decreased in both chronic liver disease and acute liver failure, with improved supportive care, targeted treatments for underlying cause of liver disease, and the advent of liver transplantation. Concurrently, there has been increased recognition of the risk of thrombosis in chronic liver disease, with a predilection for the splanchnic vasculature. This review describes the incidence of bleeding and thrombosis in chronic liver disease and acute liver failure, including the periprocedural and liver transplantation setting.

Inferior Vena Cava Constriction After Liver Transplantation Is a Severe Complication Requiring Individually Adapted Treatment: Report of a Single-Center Experience

Background

Reports on vena cava occlusion after liver transplantation (LT) are rare, but this finding represents a severe complication in the early postoperative period. In the context of the complex presentation of a patient after LT, symptoms are often misinterpreted and can be subtle.

Material/Methods

In our cohort of 138 LTs performed between 2014 and 2017 at our University’s Transplantation Department, 117 transplantations were valid for further analysis after exclusion of pediatric transplantations and transplants with primary non-function grafts. In 101 cases (73%), patients received a deceased-donor full-size organ. Living-donor LT was performed in 8 patients (6.4%) and 8 patients (6.4%) received a split graft. We report on 6 patients who had inferior vena cava (IVC) occlusion and summarize the treatment choices.

Results

In our series, patients with positive findings (age 38–70 years) received an orthotopic full-size deceased-donor graft with end-to-end IVC anastomosis. In the subsequent period, imaging revealing IVC occlusion was done on a follow-up basis (n=2), due to dyspnea (n=1), and for progressive ascites (n=2). In 3 cases, a thrombus was found. We give detailed information on our treatment options from interventional treatment to transcardial thrombus removal and anastomosis augmentation.

Conclusions

IVC constriction and subsequent thrombosis are severe complications after LT that require individually adapted treatment in specialized centers. Since patients often present with subclinical symptoms, vascular diagnosis should be performed early to detect caval anastomosis pathologies. Despite regular ultrasonography, we favor CT and cavography for subsequent quantification. We also review the literature on IVC occlusion after LT.

Liver Transplantation

The field of liver transplantation has changed since the MELD scoring system became the most widely used donor allocation tool. Due to the MELD-based allocation system, sicker patients with higher MELD scores are being transplanted. Persistent organ donor shortages remain a challenging issue, and as a result, the wait-list mortality is a persistent problem for most of the regions. This chapter focuses on deceased donor and live donor liver transplantation in patients with complications of portal hypertension. Special attention will also be placed on donor-recipient matching, perioperative management of transplant patients, and the impact of hepatic hemodynamics on transplantation.

Outcome of Liver Transplant Patients With Intraoperative-Detected Portal Vein Thrombosis: A Retrospective Cohort Study in Shiraz, Iran

OBJECTIVES

We aimed to determine outcomes and predictors of intraoperative-detected portal vein thrombosis in liver transplant recipients.

MATERIALS AND METHODS

We retrospectively analyzed 806 adult liver transplant recipients from Shiraz, Iran, to determine those with intraoperative-detected portal vein thrombosis. Patients with this complication were compared with age- and sex-matched patients without this complication. Background diseases, surgery parameters, hospital admission, reoperation, rethrombosis, acute rejection, and use of antico-agulants were assessed. Cox proportional hazards, logistic regression, and random classification forest and random survival forest plots were used for data analyses.

RESULTS

Mean age of patients was 44.7 ± 13.2 years. Patients with intraoperative-detected portal vein thrombosis (n = 91; 11.3%) had mortality ratio of 2.9 (range, 1.0-8.6) and 2-year survival of 78% versus 2-year survival rate of 92% in patients without this disease. Median time of survival in patients with this complication who died was 2 weeks versus 10 months in patients who died and did not have this complication. Random classification forest plots showed that high fasting blood sugar, autoimmune hepatitis, low prothrombin time, and cryptogenic cirrhosis were (in order) the main predictors of this complication. Random survival forest plots revealed that low prothrombin time, having intraoperative-detected portal vein thrombosis, Model for End Stage Liver Disease score, primary sclerosing cholangitis, diabetes mellitus, and hepatocellular carcinoma were (in order) the main predictors of death in liver transplant recipients. Low body mass index was associated with mortality in patients with intraoperative-detected portal vein thrombosis (by Cox proportional hazards).

CONCLUSIONS

One of every 9 liver transplant patients had intraoperative-detected portal vein thrombosis. Hazard of death was 2.9, and death occurred far earlier in patients with this complication. Improvements in diabetes mellitus care, prothrombin time, Model for End-Stage Liver Disease score, and body mass index may improve outcomes of these patients.

Autoimmune conditions are associated with perioperative thrombotic complications in liver transplant recipients: A UNOS database analysis

BACKGROUND

End stage liver disease (ESLD) is associated with significant thrombotic complications. In this study, we attempted to determine if patients with ESLD, due to oncologic or autoimmune diseases, are susceptible to thrombosis to a greater extent than patients with ESLD due to other causes.

METHODS

In this retrospective study, we analyzed the UNOS database to determine the incidence of thrombotic complications in orthotopic liver transplant (OLT) recipients with autoimmune and oncologic conditions. Between 2000 and 2012, 65,646 OLTs were performed. We found 4,247 cases of preoperative portal vein thrombosis (PVT) and 1,233 cases of postoperative vascular thrombosis (VT) leading to graft failure.

RESULTS

Statistical evaluation demonstrated that patients with either hepatocellular carcinoma (HCC) or autoimmune hepatitis (AIC) had a higher incidence of PVT (p = 0.05 and 0.03 respectively). Patients with primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and AIC had a higher incidence of postoperative VT associated with graft failure (p < 0.0001, p < 0.0001, p = 0.05 respectively). Patients with preoperative PVT had a higher incidence of postoperative VT (p < 0.0001). Multivariable logistic regression demonstrated that patients with AIC, and BMI ≥40, having had a transjugular intrahepatic portosystemic shunt, and those with diabetes mellitus were more likely to have preoperative PVT: odds ratio (OR)(1.36, 1.19, 1.78, 1.22 respectively). Patients with PSC, PBC, AIC, BMI ≤18, or with a preoperative PVT were more likely to have a postoperative VT: OR (1.93, 2.09, 1.64, 1.60, and 2.01, respectively).

CONCLUSION

Despite the limited number of variables available in the UNOS database potentially related to thrombotic complications, this analysis demonstrates a clear association between autoimmune causes of ESLD and perioperative thrombotic complications. Perioperative management of patients at risk should include strategies to reduce the potential for these complications.

Vascular complications after adult living donor liver transplantation: Evaluation with ultrasonography

Living donor liver transplantation (LDLT) has been widely used to treat end-stage liver disease with improvement in surgical technology and the application of new immunosuppressants. Vascular complications after liver transplantation remain a major threat to the survival of recipients. LDLT recipients are more likely to develop vascular complications because of their complex vascular reconstruction and the slender vessels. Early diagnosis and treatment are critical for the survival of graft and recipients. As a non-invasive, cost-effective and non-radioactive method with bedside availability, conventional gray-scale and Doppler ultrasonography play important roles in identifying vascular complications in the early postoperative period and during the follow-up. Recently, with the detailed vascular tracing and perfusion visualization, contrast-enhanced ultrasound (CEUS) has significantly improved the diagnosis of postoperative vascular complications. This review focuses on the role of conventional gray-scale ultrasound, Doppler ultrasound and CEUS for early diagnosis of vascular complications after adult LDLT.

Preoperative hepatic hemodynamics in the prediction of early portal vein thrombosis after liver transplantation in pediatric patients with biliary atresia

BACKGROUND

Portal vein thrombosis (PVT) is one of the main vascular complications after liver transplantation (LT), especially in pediatric patients with biliary atresia (BA). This study aimed to assess the preoperative hepatic hemodynamics in pediatric patients with BA using Doppler ultrasound and determine whether ultrasonographic parameters may predict early PVT after LT.

METHODS

One hundred and twenty-eight pediatric patients with BA younger than 3 years of age underwent Doppler ultrasound within seven days before LT, between October 2006 and June 2013. The preoperative hepatic hemodynamic parameters were then compared between patients with early PVT (within 1 month following LT) and those without PVT. Receiver operating characteristic analysis was performed to determine the optimal cutoff value for predicting early PVT.

RESULTS

Of the 128 transplant recipients, 41 (32.03%) had a hypoplastic portal vein (PV), 52 (40.63%) had hepatofugal PV flow and 40 (31.25%) had a high hepatic artery resistance index (HARI) of ≥1. Nine cases (7.03%) experienced early PVT. A PV diameter ≤4 mm (sensitivity 88.89%, specificity 72.27%), and a hepatofugal PV flow (sensitivity 77.78%, specificity 62.18%) with a high HARI ≥1 (sensitivity 77.78%, specificity 72.27%) were hepatic hemodynamic risk factors for early PVT.

CONCLUSIONS

Hepatic hemodynamic disturbances in pediatric recipients with BA were more common. Small PV diameter (≤4 mm) and hepatofugal PV flow combined with high HARI (≥1) are strong warning signs of early PVT after LT in pediatric patients with BA. Intense monitoring of vascular patency and prophylactic thrombolytic therapy should be considered in pediatric patients undergoing LT for BA.

Novel insights into the development of portal vein thrombosis in cirrhosis patients

The prognostic impact of portal vein thrombosis (PVT) in liver cirrhosis remains controversial among studies, primarily because the risk stratification of PVT is often lacking. A definition of clinically significant PVT should be proposed and actively improved. Moreover, the risk factors for the development of PVT in liver cirrhosis should be fully recognized to screen and identify high-risk patients. Currently, well-recognized risk factors include a reduced portal vein flow velocity, a worse liver function, splenectomy, liver transplantation, and factor V Leiden and prothrombin G20210A mutations. Novel risk factors include an increased flow volume of portosystemic collateral vessel, thrombopoietin receptor agnonists, and non-selective beta-blockers. In contrast to the traditional perspectives, the abnormalities of procoagulant and anticoagulant factors may not contribute to the development of PVT in liver cirrhosis. Further studies should explore the role of other risk factors, such as antiphospholipid antibodies, methylenetetrahydrofolate reductase C677T gene mutation, hyperhomocysteinemia, and myeloproliferative neoplasms.

Liver Transplantation in Patients with Portal Vein Thrombosis: Comparing Pre-MELD and MELD era

BACKGROUND

Portal vein thrombosis (PVT) used to be a relative contraindication for liver transplantation (LT). This obstacle has been dealt with following the improvement of LT-related techniques.

OBJECTIVE

To compare the outcome of adult patients with PVT who underwent LT before and after adopting MELD.

METHODS

We retrospectively searched our database for deceased donor LT recipients who had PVT, were operated between 1990 and 2009, and were 18 years old or more. The outcome of patients operated in pre-MELD era (1990-2001) was then compared with that of those operated in MELD era (2002-2009).

RESULTS

The incidence of patients undergoing LT with PVT has increased from 1.2% (491/40,730) in pre-MELD era to 6% (2540/42,601) in MELD era (p<0.01). Patients with PVT in MELD era were older (53.6 vs 50.5), had higher calculated MELD (21.3 vs 18.9), shorter length of hospital stay after LT (25 vs 21.7 days), more likely to develop HCC (14.8% vs 0), and more likely to receive DCD allograft (3.9% vs 0.8%). Donor risk indices were comparable in both groups (1.9 vs 1.9). The median waiting time before transplantation decreased during MELD era (71 vs 99 days). Allograft and patients survival was comparable between the two eras. However, allograft and patients survival rates were lower in patients with PVT compared to those without. In Cox regression analysis, PVT was associated with worse allograft (HR=1.3, 95% CI: 1.2-1.4, p<0.001) and patient survival (HR=1.3, 95% CI: 1.2-1.5, p<0.001) compared to non-PVT patients.

CONCLUSIONS

The incidence of patients with PVT has increased in MELD era without improvement in outcomes. Donor and recipients characteristics changed in MELD era. PVT is still associated with poor outcomes compared to patients without PVT.

Occlusive portal vein thrombosis as a new marker of decompensated cirrhosis

Natural history of liver cirrhosis is divided into compensated and decompensated stage. Traditionally, the markers of decompensated cirrhosis include ascites, variceal hemorrhage, hepatic encephalopathy and jaundice. The clinical importance of portal vein thrombosis (PVT) is increasingly recognized in patients with liver cirrhosis. The presence of PVT is not only an independent predictor of failure to control active variceal bleeding and prevent variceal rebleeding, but also significantly associated with increased mortality in patients with liver cirrhosis. Besides, it greatly influences the technical success and outcome of endovascular interventional treatment and liver transplantation for liver cirrhosis and its secondary portal hypertension. Thus, we hypothesize that PVT should be regarded as a critical marker of decompensated cirrhosis, whether clinical events such as the development of ascites, encephalopathy, and variceal bleeding occur or not. Our hypothesis adds PVT into the definition of decompensated cirrhosis and reminds clinicians and investigators that PVT plays a vital role in natural history of liver cirrhosis. Further, it is essential to construct a new system of preventing and treating liver cirrhosis in the presence of PVT.

Prevention and treatment of rethrombosis after liver transplantation with an implantable pump of the portal vein

Implantable pumps have been used to prevent deep vein thrombosis and other diseases. In this article, we report for the first time the prevention and treatment of rethrombosis of the portal vein in liver transplantation with an implantable pump of the portal vein. Four hundred four orthotopic liver transplantation cases were retrospectively reviewed and divided into 3 groups: portal vein thrombosis (PVT) patients with an implantable pump (n = 28), PVT patients without an implantable pump (n = 20), and patients without preexisting PVT (n = 356). The following parameters for the 3 groups of patients were calculated and compared: (1) preoperative parameters, including baseline data of the donors and recipients and times of graft ischemia; (2) intraoperative and postoperative parameters, including surgery time, red blood cell and plasma transfusion, platelet concentrate transfusion, bleeding and primary graft malfunction, and duration of the hospital and intensive care unit stays; and (3) follow-up information for the patency of the portal vein, rethrombosis rate, stenosis and reoperation (relaparotomy or retransplantation), in-hospital mortality, and actuarial 1-year survival rate. Among the 3 groups of recipients, no significant differences were detected in preoperative and intraoperative parameters. However, compared to PVT patients without an implantable pump, PVT patients with an implantable pump showed remarkable reductions in their postoperative hospital stay, rethrombosis, reoperation rate, and in-hospital mortality. An implantable pump of the portal vein in liver transplantation patients can prevent and facilitate the treatment of portal vein rethrombosis and is associated with a reduction of in-hospital mortality.

CEUS: A new imaging approach for postoperative vascular complications after right-lobe LDLT

AIM: To investigate contrast-enhanced ultrasound (CEUS) for early diagnosis of postoperative vascular complications after right-lobe living donor liver transplantation (RLDLT).

METHODS: The ultrasonography results of 172 patients who underwent RLDLT in West China Hospital, Sichuan University from January 2005 to June 2008 were analyzed retrospectively. Among these 172 patients, 16 patients’ hepatic artery flow and two patients’ portal vein flow was not observed by Doppler ultrasound, and 10 patients’ bridging vein flow was not shown by Doppler ultrasound and there was a regional inhomogeneous echo in the liver parenchyma upon 2D ultrasound. Thus, CEUS examination was performed in these 28 patients.

RESULTS: Among the 16 patients without hepatic artery flow at Doppler ultrasound, CEUS showed nine cases of slender hepatic artery, six of hepatic arterial thrombosis that was confirmed by digital subtraction angiography and/or surgery, and one of hepatic arterial occlusion with formation of lateral branches. Among the two patients without portal vein flow at Doppler ultrasound, CEUS showed one case of hematoma compression and one of portal vein thrombosis, and both were confirmed by surgery. Among the 10 patients without bridging vein flow and with liver parenchyma inhomogeneous echo, CEUS showed regionally poor perfusion in the inhomogeneous area, two of which were confirmed by enhanced computed tomography (CT), but no more additional information about bridging vein flow was provided by enhanced CT.

CONCLUSION: CEUS may be a new approach for early diagnosis of postoperative vascular complications after RLDLT, and it can be performed at the bedside.