Perioperative thrombotic complications in liver transplantation

Median arcuate ligament syndrome and arterial anastomotic bleeding inducing hepatic artery thrombosis after liver transplantation: A case report

RATIONALE

Median arcuate ligament (MAL) may compress the coeliac trunk inducing median arcuate ligament syndrome (MALS). MALS is a risk factor for hepatic artery thrombosis (HAT) in liver transplant recipients.

PATIENT CONCERNS

A thin female complained about upper abdominal pain for two months.

DIAGNOSES

The patient was diagnosed as primary biliary cirrhosis.

INTERVENTIONS

The patient received two liver transplantations. During the first liver transplantation, the hepatic artery (HA) pulsations were normal. Doppler B ultrasonography showed normal blood flow in the HA in the first week. A 4 cm hematoma was detected in the first porta hepatis. On the ninth day, the hematoma had increased to 9 cm along with development of HAT. Exploratory laparotomy was performed. Bleeding at the site of arterial anastomosis was considered to be the reason for the hematoma. Doppler imaging revealed no blood flow in the liver. Computed tomography angiography demonstrated MALS. Salvage liver transplantation combined with dissection of MAL was performed. The maximum velocity of HA increased to 87 cm/s.

OUTCOMES

The patient was discharged from the hospital 17 days after the second transplantation. At discharge, the liver function was normal and Doppler showed good blood flow in the HA.

LESSONS

MALS can cause HAT after liver transplantation. Before the liver transplantation, we should use Doppler B ultrasonography and sagittal CT imaging to judge whether the patient is with MALS. Also, before arterial anastomosis in liver transplantation is conducted, we should observe the impacts on the HA caused by pre-blocking gastroduodenal artery, which determines if we are supposed to do MAL dissection or bridge HA with aorta.

Bleeding and thrombotic complications of pediatric liver transplant

BACKGROUND

Pediatric patients undergoing liver transplant are at significant risk for bleeding and thrombotic complications due to the complex nature of rebalanced hemostasis in patients with liver disease.

METHODS/OBJECTIVES

We reviewed records of 92 pediatric liver and multivisceral transplant cases at Duke University Medical Center between January 2009 and December 2015. The goal was to define the nature and incidence of bleeding and thrombotic complications in this cohort and define potential risk factors.

RESULTS

There were 24 major bleeding events in 19 transplants (incidence 20.7%) and 30 thrombotic events in 23 transplants (incidence 25%). Five of the 10 retransplantations were for vascular thrombotic complications. Thirty-day mortality was 4.9%, and three of these four deaths were due to vascular thrombosis. No bleeding events led to retransplantation or mortality. Prophylactic aspirin was associated with decreased risk of thrombosis without increased bleeding. Prophylactic heparin did not increase bleeding risk. Laboratory assays predicted events poorly, apparently failing to capture the nuanced and dynamic interplay between pro- and anticoagulant factors in the posttransplant patient.

CONCLUSIONS

Both bleeding and thrombosis are frequent in this population, but only thrombotic complications contributed to retransplantation and mortality. A standardized approach to coagulation testing and antithrombotic therapy may be useful in predicting and reducing adverse outcomes. Alternative approaches to monitoring hemostasis need to be prospectively investigated in this complex patient population.

Renal Infarction during Anticoagulant Therapy after Living Donor Liver Transplantation

Introduction

Liver transplant recipients are at risk for complications of vascular thrombosis. The reconstructed hepatic artery and portal vein thrombosis potentially result in hepatic failure and graft loss. Renal infarction is a rare clinical condition, but in severe cases, it may lead to renal failure. We herein report a case of renal infarction after living donor liver transplantation (LDLT) during anticoagulant therapy.

Case Presentation

A 60-year-old woman with end-stage liver disease due to primary biliary cholangitis underwent LDLT with splenectomy. Postoperatively, tacrolimus, mycophenolate mofetil, and steroid were used for initial immunosuppression therapy. On postoperative day (POD) 5, enhanced computed tomography (CT) revealed splenic vein thrombosis, and anticoagulant therapy with heparin followed by warfarin was given. Follow-up enhanced CT on POD 20 incidentally demonstrated right renal infarction. The patient's renal function was unchanged and the arterial flow was good, and the splenic vein thrombosis resolved. At 4 months postoperatively, warfarin was discontinued, but she developed recurrent splenic vein thrombosis 11 months later, and warfarin was resumed. As of 40 months after transplantation, she discontinued warfarin and remains well without recurrence of splenic vein thrombosis or renal infarction.

Conclusion

Renal infarction is a rare complication of LDLT. In this case, renal infarction was incidentally diagnosed during anticoagulant therapy and was successfully treated.

The use of nonselective beta blockers is a risk factor for portal vein thrombosis in cirrhotic patients

BACKGROUND/AIM

A reduction in portal vein inflow velocity seems to predispose to the emergence of portal vein thrombosis (PVT). Nonselective β-blockers (NSBBs), used to prevent variceal bleeding, may increase the development of PVT by reducing portal vein inflow velocity. In this retrospective case-control study, we evaluated the risk factors and clinical features of a first event of PVT in 130 cirrhotics, 19 (15%) with (PVT group) and 111 (85%) without PVT (non-PVT group).

PATIENTS AND METHODS

Patient evaluation and NNBB treatment were carried out according to the AASLD guidelines.

RESULTS

PVT was prevalently partial (84%) and asymptomatic (84%). Patients with PVT were treated with different regimens, and resolution of thrombosis was observed in about 50% of the cases. In both groups, HCV was the most frequent cause of cirrhosis and Child-Pugh score A was prevalent. Ascites and esophageal varices were more frequent in the PVT group (P = 0.05 and <0.000, respectively). Treatment with NSBBs was significantly more frequent in the PVT group than in the non-PVT group (P < 0.000). PVT was associated with higher prevalence of chronic renal disease (P = 0.002), higher PT impairment (P = 0.003) and lower AST and ALT (P = 0.000). At multivariate logistic regression analysis, history of esophageal varices (P = 0.007) and NSBB treatment (P = 0.0003) were independent risk factors significantly associated with PVT.

CONCLUSIONS

Esophageal varices and NSBB treatment were independent risk factors of PVT. Larger studies should evaluate the risk between variceal bleeding and portal vein thrombosis of using NSBBs, particularly in the prevention of first bleeding in nonadvanced liver cirrhosis.

Cardiovascular disease risk in patients receiving organ transplantation: a national cohort study

Although organ transplantation is the definitive treatment for end-stage organ failure, the post-transplant outcomes can be substantially influenced by cardiovascular complications. A national cohort study was performed to estimate risks of cardiovascular diseases in those with heart, lung, kidney, and liver transplantation. This cohort study consisted of 5978 solid organ transplantations identified using the Taiwan National Health Insurance Database. Cardiovascular and mortality risks in transplant recipients were evaluated using standardized incidence ratios, excess absolute risks, and standardized mortality ratios as compared to those in the general population. In heart, kidney, and liver recipients, the standardized incidence ratios of overall cardiovascular diseases were 9.41 (7.75-11.44), 3.32 (2.29-3.77), and 1.4 (1.15-1.7) and the overall standardized mortality ratios were 5.23 (4.54-6.03), 1.48 (1.34-1.63), and 3.95 (3.64-4.28), respectively. Except for heart organ recipients who were at highest risk for coronary artery disease with a standardized incidence ratio of 13.12 (10.57-16.29), kidney and liver organ recipients had a ninefold increased risk in developing deep vein thrombosis post-transplant. In conclusion, solid organ transplant patients are at risk of cardiovascular disease, in particular, deep vein thrombosis, which may warrant early identification of high-risk patients in addition to prompt and adequate thromboprophylaxis perioperatively.

African Americans have a lower prevalence of portal vein thrombosis at the time of liver transplantation

BACKGROUND

Perioperative vascular thrombotic events in patients undergoing liver transplantation (LT) are associated with significant morbidity and mortality.

METHODS

In this retrospective UNOS database analysis, we evaluated the prevalence of portal vein thrombosis (PVT) and factors contributing to PVT development in different ethnic groups.

RESULTS

Of the 47 953 LT performed between 2002 and 2015, we identified 3642 cases of PVT. African Americans (AA) had a significantly lower prevalence of PVT compared to other ethnic groups (p = 0.0001). Multivariable regression analysis confirmed that AA were less likely than other ethnicities to have PVT (OR = 0.6). AA cohort was more likely to have infectious or autoimmune causes of liver failure (OR = 1.6, 1.7 respectively) as well as higher creatinine and INR compared to other groups (OR = 1.6, 1.3 respectively). AA's were less likely to have encephalopathy, ascites, or variceal bleeding, which might indicate lower portal pressures. AA's were listed for LT later than other ethnicities and had both a lower functional status and higher MELD score at the time of registration.

DISCUSSION

AA's had a significantly lower prevalence of preoperative PVT despite having a greater number of factors predisposing to thrombosis. This predisposition should be considered before instituting perioperative antithrombotic therapy.

Pulmonary injury at the anhepatic phase without veno-venous bypass in portal hypertensive rats

OBJECTIVE

In order to understand the characterization and evolution of pulmonary injury, a portal hypertension rat model was used to imitate the anhepatic phase during standard orthotopic liver transplantation without veno-venous bypass.

METHODS

In this study, 135 healthy male Wistar rats were selected; in which 15 rats were assigned in the normal control (NC) group and the remaining 120 rats were used to establish a recoverable prehepatic portal hypertension model, which were further evenly divided into eight groups after ischemia-reperfusion: portal hypertensive control group (PHTC), R0h, R6h, R12h, R24h, R48h, R72h, and R7d groups. Meanwhile, arterial blood pressure, dry-to-wet weight ratios of the lung, alanine aminotransferase (ALT) level in serum, arterial oxygen pressure (PaO₂), and myeloperoxidase (MPO) activity in lung tissue were measured. Morphology changes of the lung were observed using an optical microscope and a transmission electron microscope.

RESULTS

The portal hypertension rat model was successfully established three weeks after the first operation. These portal hypertensive rats could withstand 1 hour at the anhepatic phase. Pulmonary injury severity increased to the most at 12-24 hours, and decreased to normal at seven days after reperfusion.

CONCLUSION

Ischemia-reperfusion injury is an important mechanism that results in pulmonary injury after liver transplantation. It is safe for portal hypertensive rats to tolerate 1 hour at the anhepatic phase. Pulmonary injury was the most severe within 12-24 hours after ischemia-reperfusion.

Postoperative Care of a Liver Transplant Recipient Using a Classification System: Type A (Stable) Versus Type B (Unstable)

Liver transplantation has become an effective and valuable option for patients with end-stage liver disease and hepatocellular carcinoma. Liver failure, an acute or chronic condition, results in impaired bile production and excretion, clotting factor production, protein synthesis, and regulation of metabolism and glucose. Some acute conditions of liver disease have the potential to recover if the liver heals on its own. However, chronic conditions, such as cirrhosis, often lead to irreversible disease and require liver transplantation. In this publication, we review the pathophysiology of liver failure, examine common conditions that ultimately lead to liver transplantation, and discuss the postoperative management of patients who are either hemodynamically stable (type A) or unstable (type B).

Nontumoral portal vein thrombosis in patients awaiting liver transplantation

Portal vein thrombosis (PVT) occurs in approximately 2%-26% of the patients awaiting liver transplantation (LT) and is no longer an absolute contraindication for LT. Nearly half of PVT cases are accidentally found during the LT procedure. The most important risk factor for PVT development in cirrhosis may be the severity of liver disease and reduced portal blood flow. Whether other inherited or acquired coagulation disorders also play a role is not yet clear. The development of PVT may have no effect on the liver disease progression, especially when it is nonocclusive. PVT may not increase the risk of wait-list mortality, but it is a risk factor for poor early post-LT mortality. Anticoagulation and transjugular intrahepatic portosystemic shunt (TIPS) are 2 major treatment strategies for patients with PVT on the waiting list. The complete recanalization rate after anticoagulation is approximately 40%. The role of TIPS to maintain PV patency for LT as the primary indication has been reported, but the safety and efficacy should be further evaluated. PVT extension and degree may determine the surgical technique to be used during LT. If a "conventional" end-to-end portal anastomotic technique is used, there is not a major impact on post-LT survival. Post-LT PVT can significantly reduce both graft and patient survival after LT and can preclude future options for re-LT.

Challenging hepatitis C-infected liver transplant patients

Caring for liver transplant patients suffering from chronic hepatitis C virus (HCV) infection is a challenging task for transplant surgeons and primary physicians alike. HCV is the leading cause of liver transplantation in the USA and comes with a myriad of complications that increase morbidity and mortality. This review focuses on patient follow-up, spanning from before the liver transplant occurs to the patient's long-term health. Pretransplant, both donor and recipient variables, must be carefully chosen to ensure optimal surgical success. Risk factors must be identified and HCV viral load must be reduced to a minimum. In addition to standard transplant complications, HCV patients suffer from additional problems, such as fibrosing cholestatic hepatitis and widespread viremia. Physicians must focus on the balance of immunosuppressive and antiviral medications, while considering possible side effects from these potent drugs. Over the years following surgery, physicians must identify any signs of failing liver health, as HCV-positive patients have an increased risk for cirrhosis and certain life-threatening malignancies.