Neurologic Considerations and Complications Related to Liver Transplantation

Risk of Cerebral Aneurysm Rupture After Liver Transplantation: Development and Validation of a Hemorrhagic Stroke Scoring Model

BACKGROUND

Liver transplantation (LT) patients appear to be more prone to neurological events compared to individuals undergoing other types of solid-organ transplantation. The aims of the present study were to analyze the prevalence of unruptured intracranial aneurysms (UIAs) in patients undergoing liver transplantation (LT) and to examine the perioperative occurrence of subarachnoid hemorrhage (SAH). Also, it intended to systematically identify the risk factors of SAH and hemorrhagic stroke (HS) within a year after LT and to develop a scoring system which involves distinct clinical features of LT patients.

METHODS

Patients who underwent LT from January 2012 to March 2022 were analyzed. All included patients underwent neurovascular imaging within 6 months before LT. We conducted an analysis of prevalence and radiological features of UIA and SAH. The clinical factors that may have an impact on HS within one year of LT were also reviewed.

RESULTS

Total of 3,487 patients were enrolled in our study after applying inclusion and exclusion criteria. The prevalence of UIA was 5.4%. The incidence of SAH and HS within one year following LT was 0.5% and 1.6%, respectively. We developed a scoring system based on multivariable analysis to predict the HS within 1-year after LT. The variables were a poor admission mental status, the diagnosis of UIA, serum ammonia levels, and Model for End-stage Liver Disease (MELD) scores. Our model showed good discrimination among the development (C index, 0.727; 95% confidence interval [CI], 0.635-0.820) and validation (C index, 0.719; 95% CI, 0.598-0.801) cohorts.

CONCLUSION

The incidence of UIA and SAH was very low in LT patients. A poor admission mental status, diagnosis of UIA, serum ammonia levels, and MELD scores were significantly associated with the risk of HS within one year after LT. Our scoring system showed a good discrimination to predict the HS in LT patients.

Early neurologic complications after liver transplant are associated with reduced long-term survival and increased rates of rejection

Neurologic complications (NCs) are common following liver transplantation (LT) and have been associated with impaired short-term survival. The impact of NC on long-term survival is less defined. We aimed to characterize these outcomes and assess for risk factors for post-LT NC. We performed a single-center, retrospective review of 521 patients with LT from 2016 to 2020. Baseline clinical and laboratory factors, intraoperative events, and outcomes were compared between patients with and without NC. The 5-year overall and rejection-free survival was estimated using the Kaplan-Meier analysis. Multivariable logistic regression assessed for an independent relationship between risk factors and the development of NC. Among 521 LT recipients, 24% experienced post-LT NC. Overall and rejection-free survival at 5 years was, respectively, 69% and 75% among those with NC versus 87% and 88% among those without NC (log-rank < 0.001). Among those who survived the first 3 months after LT, overall survival but not rejection-free survival was reduced among patients with NC. Risk factors for developing NC included peri-LT serum sodium (ΔSNa) ≥ 6 (29.4% vs. 20.5%, p = 0.04), grade 3 or 4 HE pre-LT, SNa < 125 pre-LT, and more intraoperative transfusions. In a multivariable logistic regression model controlling for described variables, SNa < 125 (or 0.21, 95% CI, 0.06-0.74) at LT and pre-LT HE grade 3 or 4 (or 0.45, 95% CI, 0.26-0.76) was independently associated with NC. Long-term survival was reduced among patients who developed NC in the immediate post-transplant period, even when censoring those who died in the first 3 months. Post-LT NC was associated with perioperative ΔSNa ≥ 6. Optimization of SNa pre-LT > 125 and limiting perioperative ΔSNa <6 mEq/L might have a beneficial impact in decreasing NC post-LT, which may improve long-term post-LT survival.

2021 Clinical Update in Liver Transplantation

In 2021, the United States performed 9,236 liver transplantations, an increase of 3.7% from 2020. As the specialty of transplant anesthesiologist continues to grow, so does the body of evidence-based research to improve patient care. New technology in organ preservation offers the possibility of preserving marginal organs for transplant or improving the graft for transplantation. The sequalae of end-stage liver disease have wide-ranging consequences that affect neurologic outcomes of patients both during and after transplantation that anesthesiologists should monitor. Obesity presents several challenges for anesthesiologists. As an increasing number of patients with nonalcoholic steatohepatitis are listed for transplant, managing their multiple comorbidities can be challenging. Finally, the rebalanced hemostasis of end-stage liver disease can cause both bleeding and thrombus. Often, bleeding risks predominate as a concern, but anesthesiologists should be aware of risks of intracardiac thrombus and review therapeutic options for prevention and treatment.

Refractory Hypernatremia and Osmotic Demyelination Syndrome After Liver Transplantation: A Case Report

Osmotic demyelination syndrome is an uncommon neurologic condition, characterized by noninflammatory demyelination involving the pons and other areas of the central nervous system. As chronic hyponatremia is frequently associated with cirrhosis, patients undergoing liver transplantation are at an increased risk for developing this condition. We report the case of a patient who developed refractory hypernatremia and osmotic demyelination syndrome after liver transplantation. The patient was a 40-year-old man, who underwent liver transplantation for the treatment of cryptogenic cirrhosis, and had a preoperative sodium level of 128 mmol/L. Although there were no intraoperative complications, the patient showed signs of mental confusion and drowsiness in the second postoperative day, and we noticed an increase to 136 mmol/L in his serum sodium. Treatment with 5% dextrose and desmopressin was initiated, but his serum sodium continued to increase steadily, while his neurologic condition gradually worsened. Serum sodium rose to 157 mmol/L, and a magnetic resonance imaging of the brain showed extensive lesions consistent with osmotic demyelination syndrome. The clinical condition of the patient continued to deteriorate until his death 17 days after the transplant. Although the occurrence of this syndrome after liver transplantation is well described, the steady increase in serum sodium despite early treatment, as described in this case, is highly unusual, and highlights the great attention that must be taken with monitoring and control of serum sodium in patients who undergo liver transplant in the context of chronic hyponatremia. This manuscript is compliant with the Helsinki Congress and the Istanbul Declaration.

Cerebral Diseases in Liver Transplant Recipients: Systematic Review of Clinical Evidence

This systematic review presents clinical evidence on early and long-term cerebral diseases in liver transplant recipients. The literature search led to the retrieval of 12 relevant studies. Early postoperative cerebral complications include intracranial hemorrhage associated with a coexisting coagulopathy, perioperative hypertension, and higher MELD scores and is more frequent in critically ill recipients; central pontine and extrapontine myelinolysis are associated with notable perioperative changes in the plasma Na+ concentration and massive transfusion. Long-term follow-up cerebral complications include focal brain lesions, cerebrovascular diseases, and posterior reversible encephalopathy; there is no proven relationship between the toxicity immunosuppressive drugs and cerebral complications. This SR confirms a very low incidence of opportunistic cerebral infections.

Hepatic Encephalopathy: From Metabolic to Neurodegenerative

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome of both acute and chronic liver disease. As a metabolic disorder, HE is considered to be reversible and therefore is expected to resolve following the replacement of the diseased liver with a healthy liver. However, persisting neurological complications are observed in up to 47% of transplanted patients. Several retrospective studies have shown that patients with a history of HE, particularly overt-HE, had persistent neurological complications even after liver transplantation (LT). These enduring neurological conditions significantly affect patient's quality of life and continue to add to the economic burden of chronic liver disease on health care systems. This review discusses the journey of the brain through the progression of liver disease, entering the invasive surgical procedure of LT and the conditions associated with the post-transplant period. In particular, it will discuss the vulnerability of the HE brain to peri-operative factors and post-LT conditions which may explain non-resolved neurological impairment following LT. In addition, the review will provide evidence; (i) supporting overt-HE impacts on neurological complications post-LT; (ii) that overt-HE leads to permanent neuronal injury and (iii) the pathophysiological role of ammonia toxicity on astrocyte and neuronal injury/damage. Together, these findings will provide new insights on the underlying mechanisms leading to neurological complications post-LT.

Association between donor/recipient MTRR gene polymorphisms and the risk of new-onset neurological complications after liver transplantation

Neurological complications are very common after liver transplantation. This study focuses on clinical risk factors and susceptibility gene polymorphisms of neurological complications after liver transplantation. A better predictive model is obtained. This study proves that MTRR is an independent susceptibility gene for neurological complications. Compared with the independent risk factor of abdominal infection, MTRR has a more advantageous value in predicting neurological complications after liver transplantation.

Indian National Association for the Study of Liver Consensus Statement on Acute Liver Failure (Part-2): Management of Acute Liver Failure

Acute liver failure (ALF) is not an uncommon complication of a common disease such as acute hepatitis. Viral hepatitis followed by antituberculosis drug-induced hepatotoxicity are the commonest causes of ALF in India. Clinically, such patients present with appearance of jaundice, encephalopathy, and coagulopathy. Hepatic encephalopathy (HE) and cerebral edema are central and most important clinical event in the course of ALF, followed by superadded infections, and determine the outcome in these patients. The pathogenesis of encephalopathy and cerebral edema in ALF is unique and multifactorial. Ammonia plays a crucial role in the pathogenesis, and several therapies aim to correct this abnormality. The role of newer ammonia-lowering agents is still evolving. These patients are best managed at a tertiary care hospital with facility for liver transplantation (LT). Aggressive intensive medical management has been documented to salvage a substantial proportion of patients. In those with poor prognostic factors, LT is the only effective therapy that has been shown to improve survival. However, recognizing suitable patients with poor prognosis has remained a challenge. Close monitoring, early identification and treatment of complications, and couseling for transplant form the first-line approach to manage such patients. Recent research shows that use of dynamic prognostic models is better for selecting patients undergoing liver transplantation and timely transplant can save life of patients with ALF with poor prognostic factors.

Diffusion MRI Findings in Encephalopathy Induced by Immunosuppressive Therapy after Liver Transplantation

Neurological complications are common after liver transplantation, as they affect up to one-third of the transplanted patients and are associated with significant morbidity. The introduction of calcineurin inhibitors, cyclosporine A and tacrolimus, in immunosuppressive regimens significantly improved the outcome of solid-organ transplantation even though immunosuppression-associated neurotoxicity remains a significant complication, particularly occurring in about 25% of cases after liver transplantation. The immunosuppressant cyclosporine A and tacrolimus have been associated with the occurrence of major neurological complications, diffuse encephalopathy being the most common. The biochemical and pathogenetic basis of calcineurin inhibitors-induced neurotoxicity are still unclear although several mechanisms have been suggested. Early recognition of symptoms could help reduce neurotoxic event. The aim of the study was to evaluate cerebral changes through MRI, in particular with diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC) maps, in two patients undergoing liver transplantation after immunosuppressive therapy. We describe two patients in which clinical pictures, presenting as a severe neurological condition, early after orthotopic liver transplantation during immunosuppression therapy, showed a different evolution in keeping with evidence of focal-multifocal lesions at DWI and ADC maps. At clinical onset, DWI showed hyperintensity of the temporo-parieto-occipital cortex with normal ADC values in the patient with following good clinical recovery and decreased values in the other one; in the latter case, MRI abnormalities were still present after ten days, until the patient's exitus. The changes in DWI with normal ADC may be linked to brain edema with a predominant vasogenic component and therefore reversible, while the reduction in ADC is due to cytotoxic edema and linked to more severe, nonreversible, clinical picture. Brain MRI and particularly DWI and ADC maps provide not only a good and early representation of neurological complications during immunosuppressant therapy but can also provide a useful prognostic tool on clinical outcome of the patient.

[Anesthesiological aspects of liver transplantation]

Liver transplantation (LTPL) is the only curative option for patients with end stage liver disease (ESLD) or with hepatocellular carcinoma (HCC). Eurotransplant in Leiden, the Netherlands, is responsible for organ allocation. The model of end stage liver disease (MELD) score, which describes the severity of the liver disease, is decisive for organ allocation. The heterogeneous patient collective and hepatic-related comorbidities and their dynamics represent challenges. The anesthesiologist is responsible for evaluating the overall prognosis, whereby cardiac, pulmonary, renal and neurological comorbidities must be taken into consideration. During LTPL surgery is divided into several stages. Besides volume management, heat preservation and coagulation management, major challenges for the anesthesiologist are hemodynamic stabilization and regulation of the acid-base balance.