Autoimmune biomarkers in porto-sinusoidal vascular disease: Potential role in its diagnosis and pathophysiology

Portal Vein Thrombosis in Patients Without Cirrhosis: Current Practical Approaches and Treatment Strategies

Portal vein thrombosis in non-cirrhotic individuals, although uncommon, is an increasingly explored condition that affects mainly young people, consequently representing a significant disease burden. Reports primarily including western European populations have recently shed light regarding the pathophysiology, risk factors, natural history, treatment, and prognosis of this entity. Underlying predisposing conditions are documented in ~70% of cases, encompassing local risk factors, inherited and acquired thrombophilia, cancer, and systemic inflammatory conditions. Non-cirrhotic portal vein thrombosis can cause significant portal hypertension in the acute setting, but, more frequently, significant portal hypertension-related complications arise when the condition becomes chronic and portosystemic collaterals develop, increasing the risk for variceal bleeding and ascites. The diagnostic approach to screen for underlying thrombophilia remains a challenge, and recommendations in this regard, although scarce and backed by scarce evidence, have changed notably in the last years, leaning toward a universal screen in patients who develop this condition without a clear provoking factor. Recently, studies have shown that long-term anticoagulation may be appropriate even in the absence of clear provoking factors or underlying thrombophilia. Future studies should address which patients may benefit from this approach, which patients may not need it, and what the most appropriate strategies are to approach patients who do not recover portal vein patency with anticoagulation to further prevent portal hypertension-related complications.

The potential roles of gut microbiome in porto-sinusoidal vascular disease: an under-researched crossroad

Accumulating evidence indicates that patients with liver diseases exhibit distinct microbiological profiles, which can be attributed to the bidirectional relationship of the gut-liver axis. Porto-sinusoidal vascular disease (PSVD) has recently been introduced to describe a group of vascular diseases of the liver, involving the portal venules and sinusoids. Although the pathophysiology of PSVD is not yet fully understood, several predisposing conditions, including immunodeficiency, inflammatory bowel disease, abdominal bacterial infections are associated with the increasing in intestinal permeability and microbial translocation, supporting the role of altered gut microbiota and gut-derived endotoxins in PSVD etiopathogenesis. Recent studies have proposed that the gut microbiome may play a crucial role in the pathophysiology of intrahepatic vascular lesions, potentially influencing the onset and progression of PSVD in this context. This review aims to summarize the current understanding of the gut microbiome's potential role in the pathogenesis of hepatic microvascular abnormalities and thrombosis, and to briefly describe their interactions with PSVD. The insights into gut microbiota and their potential influence on the onset and progression of PSVD may pave the way for new diagnostic, prognostic, and therapeutic strategies.

Porto-sinusoidal vascular liver disorder with portal hypertension: Natural history and long-term outcome

BACKGROUND & AIMS

Current knowledge of the natural history of patients with porto-sinusoidal vascular disorder (PSVD) is derived from small studies. The aim of the present study was to determine the natural history of PSVD and prognostic factors in a large multicenter cohort of patients.

METHODS

We performed a retrospective study on patients with PSVD and signs of portal hypertension (PH) prospectively registered in 27 centers.

RESULTS

A total of 587 patients were included, median age of 47 years and 38% were women. Four-hundred and one patients had an associated condition, which was graded as severe in 157. Median follow-up was 68 months. At diagnosis, 64% of patients were asymptomatic while 36% had a PH-related complication: PH-related bleeding in 112 patients, ascites in 117, and hepatic encephalopathy in 11. In those not presenting with bleeding, the incidence of first bleeding was 15% at 5 years, with a 5-year rebleeding rate of 18%. The 5-year cumulative incidence of new or worsening ascites was 18% and of developing portal vein thrombosis was 16%. Fifty (8.5%) patients received a liver transplantation and 109 (19%) died, including 55 non-liver-related deaths. Transplant-free survival was 97% and 83% at 1 and 5 years, respectively. Variables independently associated with transplant-free survival were age, ascites, serum bilirubin, albumin and creatinine levels at diagnosis and severe associated conditions. This allowed for the creation of a nomogram that accurately predicted prognosis.

CONCLUSIONS

The prognosis of PSVD is strongly determined by the severity of the associated underlying conditions and parameters of liver and renal function.

IMPACT AND IMPLICATIONS

Porto-sinusoidal vascular liver disorder (PSVD) is a rare entity that usually affects young people, frequently causes severe complications of portal hypertension, and may reduce life expectancy. To date, there is scarce information regarding its clinical manifestations, natural history and prognostic factors. The present study, including the largest number of patients with PSVD reported so far, shows that overall, when managed at centers of expertise, the prognosis of patients with PSVD is good, with LT-free survival rates of 83% and 72% at 5 and 10 years, respectively. Presence and severity of an underlying associated condition, presence of ascites, age and bilirubin, albumin and creatinine levels were associated with poor prognosis. These results are important to know for hepatologists. A final model combining these parameters enabled development of a nomogram that predicts prognosis with good discrimination and calibration capacity and can be easily applied in clinical practice.

Letter: Prospective evaluation of patients with non-cirrhotic portal hypertension-A single centre study. Authors' reply

This article is linked to Mironova et al papers. To view these articles, visit https://doi.org/10.1111/apt.17987 and https://doi.org/10.1111/apt.18255

Porto-Sinusoidal Vascular Disease: A New Nomenclature Different from Idiopathic Non-Cirrhotic Portal Hypertension

BACKGROUND AND AIMS

Porto-sinusoidal vascular disease (PSVD) as a novel clinical conception was modified on the basis of idiopathic non-cirrhotic portal hypertension (INCPH). This study aimed to compare the clinical, biochemical histological features and prognosis between the diagnostic criteria for PSVD and that of INCPH.

METHODS

A total of 65 patients who underwent liver biopsies were analyzed retrospectively. The clinical, pathological and prognosis date were reviewed and screened according to the latest diagnostic criteria of PSVD and INCPH.

RESULTS

A total of 65 patients were diagnosed with PSVD, of which 31 (47.69%) also fulfilled INCPH criteria. Specific histological and specific clinical portal hypertension (PH) signs were found in 34 (52.31%) and 30 (46.15%) of the patients, respectively. PSVD patients showed higher LSM levels (11.45 (6.38, 18.08) vs. 7.90 (6.70, 13.00), p = 0.039) than the INCPH patients. INCPH patients had a higher cumulative incidence of liver-related complications than the PSVD patients (86.95% vs. 35.71%, log-rank p < 0.001).

CONCLUSION

Novel PSVD criteria facilitate early diagnosis. PSVD patients with other liver diseases may have higher LSM values. Disease progression and survival outcomes are correlated with PH in PSVD patients.

Clinical characteristics and natural history of porto-sinusoidal vascular disease: A cohort study of 234 patients in China

BACKGROUND AND AIMS

Porto-sinusoidal vascular disease (PSVD) is an under-recognized and under-diagnosed disease. The purpose of this study was to investigate the clinical features and prognosis of PSVD.

METHODS

The patients who underwent liver biopsies were analyzed retrospectively. The clinical and pathological data were reviewed and screened according to the latest diagnostic criteria of PSVD.

RESULTS

A total of 234 patients were diagnosed as PSVD, including 103 patients presented with portal hypertension (PH) and 131 patients without PH. At baseline, the alanine aminotransferase (ALT) and γ-glutamyl transpeptidase (GGT) levels were higher in the no-PH group. The liver stiffness increased in the PH group. In histological review, obliterative portal venopathy, sinusoidal dilatation and architectural disturbance were more common in the PH group, while portal tract abnormalities were more widely distributed in the no-PH group. After a median follow-up of 43.6 months, the survival rate of patients with baseline liver decompensation was 76.0%, and that of patients at a liver compensated stage in the PH group was 98.7%. First variceal bleeding occurred in 13.8% of patients with gastric-oesophageal varices. None of the patients in the no-PH group developed portal hypertension during follow-up.

CONCLUSIONS

PSVD can manifest as PH or mild liver enzyme abnormalities. There are significant differences in pathological features among patients with different clinical manifestations. Recurrent ascites are the main cause of death in PSVD patients. However, patients without PH have a slow disease progression, with recurrent elevated GGT levels being their main clinical feature.

The autoimmune landscape of Porto-sinusoidal vascular disorder: What the rheumatologist needs to know

Porto-sinusoidal vascular disorder (PSVD) encompasses a group of vascular disorders characterized by lesions of the portal venules and sinusoids with clinical manifestations ranging from non-specific abnormalities in serum liver enzymes to clinically overt portal hypertension and related complications. Several reports have documented cases of PSVD in patients with systemic autoimmune conditions, such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. It is of note that these diseases share specific pathophysiological features with PSVD, including endothelial dysfunction, vascular inflammation, and molecular signatures. This narrative review aims to summarize the current knowledge on the association between PSVD and systemic autoimmune diseases, emphasizing the importance of promptly recognizing this condition in the rheumatological practice, and highlighting the key aspects where further research is necessary from both pathogenic and clinical perspectives.

[Portosinusoidal vascular disorder: A paradigm shift]

The term portosinusoidal vascular disorder (PSVD) refers to a clinical-pathological entity that encompasses those patients with intrahepatic vascular damage without cirrhosis at risk of developing severe complications of portal hypertension. Numerous systemic diseases, genetic disorders, and toxic agents have been associated with this pathology, making its diagnosis an important clinical challenge. The recent description of uniform diagnostic criteria and a better understanding of its pathophysiology will allow for better identification of patients, even in early stages of the disease. Although there is currently no effective etiological treatment available, early diagnosis allows for the development of preventive strategies for some severe complications of portal hypertension.

The genetics of portal hypertension: Recent developments and the road ahead

Portal hypertension (PH), defined as a pathological increase in the portal vein pressure, has different aetiologies and causes. Intrahepatic PH is mostly secondary to the presence of underlying liver disease leading to cirrhosis, characterized by parenchymal changes with deregulated accumulation of extracellular matrix and vascular abnormalities; liver sinusoidal endothelial cells and hepatic stellate cells are key players in PH progression, able to influence each other. However, PH may also develop independently of parenchymal damage, as occur in portosinusoidal vascular disorder (PSVD), a group of clinical and histological entities characterized by portal vasculature dysfunctions. In this particular group of disorders, the pathophysiology of PH is still poorly understood. In the last years, several genetic studies, based on genome-wide association studies or whole-exome sequencing analysis, have highlighted the importance of genetic heritability in PH pathogenesis, both in cirrhotic and non-cirrhotic cases. The common PNPLA3 p.I148M variant, one of the main determinants of the susceptibility to steatotic liver disease, has also been associated with decompensation in patients with PH. Genetic variations at loci influencing coagulation, mainly the ABO locus, may directly contribute to the pathogenesis of PH. Rare genetic variants have been associated with familiar cases of progressive PSVD. In this review, we summarize the recent knowledges on genetic variants predisposing to PH development, contributing to better understand the role of genetic factors in PH pathogenesis.

A Narrative Review on Non-Cirrohotic Portal Hypertension: Not All Portal Hypertensions Mean Cirrhosis

Non-cirrhotic portal hypertension (NCPH), also known as idiopathic non-cirrhotic portal hypertension (INCPH) and porto-sinusoidal vascular disorder (PSVD), is a rare disease characterized by intrahepatic portal hypertension (IPH) in the absence of cirrhosis. The precise etiopathogenesis of IPH is an area of ongoing research. NCPH diagnosis is challenging, as there are no specific tests available to confirm the disease, and a high-quality liver biopsy, detailed clinical information, and an expert pathologist are necessary for diagnosis. Currently, the treatment of NCPH relies on the prevention of complications related to portal hypertension, following current guidelines of cirrhotic portal hypertension. No treatment has been studied that aimed to modify the natural history of the disease; however, transjugular intrahepatic porto-systemic shunt (TIPS) placement, shunt and liver transplantation are considerable symptomatic options. In this review, we discuss the heterogeneity of NCPH as well as its etiopathogenesis, clinical presentation and management issues. Starting from the assumption that portal hypertension does not always mean cirrhosis, cooperative studies are probably needed to clarify the issues of etiology and the possible genetic background of this rare disease. This knowledge might lead to better treatment and perhaps better prevention.

Molecular Mechanisms Underlying Vascular Liver Diseases: Focus on Thrombosis

Vascular liver disorders (VLDs) comprise a wide spectrum of clinical-pathological entities that primarily affect the hepatic vascular system of both cirrhotic and non-cirrhotic patients. VLDs more frequently involve the portal and the hepatic veins, as well as liver sinusoids, resulting in an imbalance of liver homeostasis with serious consequences, such as the development of portal hypertension and liver fibrosis. Surprisingly, many VLDs are characterized by a prothrombotic phenotype. The molecular mechanisms that cause thrombosis in VLD are only partially explained by the alteration in the Virchow's triad (hypercoagulability, blood stasis, and endothelial damage) and nowadays their pathogenesis is incompletely described and understood. Studies about this topic have been hampered by the low incidence of VLDs in the general population and by the absence of suitable animal models. Recently, the role of coagulation imbalance in liver disease has been postulated as one of the main mechanisms linked to fibrogenesis, so a novel interest in vascular alterations of the liver has been renewed. This review provides a detailed analysis of the current knowledge of molecular mechanisms of VLD. We also focus on the promising role of anticoagulation as a strategy to prevent liver complications and to improve the outcome of these patients.

Porto-sinusoidal vascular disorder

It is well established that portal hypertension can occur in the absence of cirrhosis, as reported in patients with immune disorders, infections and thrombophilia. However, similar histological abnormalities primarily affecting the hepatic sinusoidal and (peri)portal vasculature have also been observed in patients without portal hypertension. Thus, the term porto-sinusoidal vascular disorder (PSVD) has recently been introduced to describe a group of vascular diseases of the liver featuring lesions encompassing the portal venules and sinusoids, irrespective of the presence/absence of portal hypertension. Liver biopsy is fundamental for PSVD diagnosis. Specific histology findings include nodular regenerative hyperplasia, obliterative portal venopathy/portal vein stenosis and incomplete septal fibrosis/cirrhosis. Since other conditions including alcohol-related and non-alcoholic fatty liver disease, or viral hepatitis, or the presence of portal vein thrombosis may occur in patients with PSVD, their relative contribution to liver damage should be carefully assessed. In addition to histology and clinical diagnostic criteria, imaging and non-invasive tests such as liver and spleen stiffness measurements could aid in the diagnostic workup. The introduction of PSVD as a novel clinical entity will facilitate collaborative studies and investigations into the underlying molecular pathomechanisms encompassed by this term.