Diagnostic challenges in non-cirrhotic portal hypertension - porto sinusoidal vascular disease

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.

Porto-sinusoidal Vascular Disease: Classification and Clinical Relevance

Non-cirrhotic portal hypertension (NCPH) is a well-recognized clinico-pathological entity, which is associated with clinical signs and symptoms, imaging, and endoscopic features of portal hypertension (PHT), in absence of cirrhosis. In patients with NCPH without known risk factors of PHT or extrahepatic portal vein thrombosis, the condition is called idiopathic non-cirrhotic portal hypertension (INCPH). There are multiple infectious, immune related causes, systemic diseases, drug and toxin exposures, haematological disorders, and metabolic risk factors that have been associated with this INCPH. However, the causal pathogenesis is still unclear. The Vascular liver disorders interest group group recently proposed porto-sinusoidal vascular disease (PSVD) as a syndromic entity, which provides definite histopathological criteria for diagnosis of NCPH (table 1). The three classical histo-morphological lesions specific for PSVD include obliterative portal venopathy, nodular regenerative hyperplasia, and incomplete septal fibrosis. The PSVD definition includes patients with portal vein thrombosis, PVT, and even those without PHT, thus broadening the scope of diagnosis to include patients who may have presented early, prior to haemodynamic changes consistent with PHT. However, this new diagnosis has pros and cons. The cons include mandating invasive liver biopsy to assess the PSVD histological triad in all patients with NCPH, an erstwhile clinical diagnosis in Asian patients. In addition, the natural history of the subclinical forms of PSVD without PHT and linear progression to develop PHT is unknown yet. In this review, we discuss the diagnosis and treatment of INCPH/PSVD, fallacies and strengths of the old and new schema, pathobiology of this disease, and clinical correlates in an Asian context. Although formulation of standardised diagnostic criteria is useful for comparison of clinical cohorts with INCPH/PSVD, prospective clinical validation in global cohorts is necessary to avoid misclassification of vascular disorders of the liver.

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.

Congestive Hepatopathy: Pathophysiology, Workup, and Imaging Findings with Pathologic Correlation

Liver congestion is increasingly encountered in clinical practice and presents diagnostic pitfalls of which radiologists must be aware. The complex altered hemodynamics associated with liver congestion leads to diffuse parenchymal changes and the development of benign and malignant nodules. Distinguishing commonly encountered benign hypervascular lesions, such as focal nodular hyperplasia (FNH)-like nodules, from hepatocellular carcinoma (HCC) can be challenging due to overlapping imaging features. FNH-like lesions enhance during the hepatic arterial phase and remain isoenhancing relative to the background liver parenchyma but infrequently appear to wash out at delayed phase imaging, similar to what might be seen with HCC. Heterogeneity, presence of an enhancing capsule, washout during the portal venous phase, intermediate signal intensity at T2-weighted imaging, restricted diffusion, and lack of uptake at hepatobiliary phase imaging point toward the diagnosis of HCC, although these features are not sensitive individually. It is important to emphasize that the Liver Imaging Reporting and Data System (LI-RADS) algorithm cannot be applied in congested livers since major LI-RADS features lack specificity in distinguishing HCC from benign hypervascular lesions in this population. Also, the morphologic changes and increased liver stiffness caused by congestion make the imaging diagnosis of cirrhosis difficult. The authors discuss the complex liver macro- and microhemodynamics underlying liver congestion; propose a more inclusive approach to and conceptualization of liver congestion; describe the pathophysiology of liver congestion, hepatocellular injury, and the development of benign and malignant nodules; review the imaging findings and mimics of liver congestion and hypervascular lesions; and present a diagnostic algorithm for approaching hypervascular liver lesions. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Transjugular Intrahepatic Portosystemic Shunt in Nonmalignant Noncirrhotic Portal Vein Thrombosis and Portosinusoidal Vascular Disorder

Transjugular intrahepatic portosystemic shunt (TIPS) emerges as a key treatment for portal hypertension (PH) complications. While international guidelines provide clear indications for its use in cirrhosis, empirical knowledge is notably scarcer in non-cirrhotic PH, particularly in nonmalignant noncirrhotic portal vein thrombosis (NNPVT) and in patients with portosinusoidal vascular disorder (PSVD). Patients afflicted by these rare diseases exhibit distinct clinical profiles compared to their cirrhotic counterparts, often characterized by a younger age, predominantly preserved hepatic functionality even in cases of severe PH, and a higher propensity for extensive splanchnic thrombosis, which intricately complicates TIPS placement, posing unique challenges for its creation. The objective of this review is to synthesize existing literature on the effectiveness, safety, specific indications, and clinical outcomes of TIPS in adult patients with NNPVT or PSVD, focusing also on the technical challenges of TIPS insertion in the presence of portal cavernoma.

Diagnostic performance of transient elastography in differentiation between porto-sinusoidal vascular liver disease and compensated cirrhosis

BACKGROUND AND AIMS

The efficacy of transient elastography (TE) in the differential diagnosis between porto-sinusoidal vascular disease (PSVD) and compensated cirrhosis has not been sufficiently studied. We aimed to investigate the diagnostic performance of TE and identify histological lesions associated with liver stiffness.

METHODS

We conducted a retrospective cohort study including patients with PSVD and cirrhosis (Child-Turcotte-Pugh class A) and healthy subjects. Both the PSVD and cirrhotic patients had at least one sign of PH. The area under the receiver operating characteristic curve (AUROC) was used for differentiation.

RESULTS

Ninety-two patients with PSVD (median age: 53 years, 33% male), 100 patients with compensated cirrhosis and 101 healthy subjects were included. The median TE-LSM in the PSVD patients (10.0 [7.0-13.0] kPa) was significantly lower than that in the cirrhotic patients (21.0 [15.0-28.0] kPa, p < .001) but was significantly higher than that in the healthy subjects (5.1 [4.6-6.0] kPa, p < .001). The AUROCs of TE-LSM for the discrimination of PSVD from the cirrhosis and healthy subjects were 0.886 (95% CI: 0.833-0.928) and 0.913 (95% CI: 0.864-0.949), respectively. The sensitivity and specificity to discriminate PSVD from compensated cirrhosis were 78.3% and 82.0%, respectively, at a cut-off of 13.6 kPa. Furthermore, portal fibrosis and aberrant cytokeratin 7 expression of centrilobular hepatocytes were significantly associated with higher TE-LSM (≥10.0 kPa).

CONCLUSION

TE-LSM can be used to differentiate PSVD from compensated cirrhosis. Pathological features in association with increased liver stiffness are identified.

Noninvasive differentiation of porto-sinusoidal vascular disorder from cirrhosis: a systematic review

BACKGROUND

Porto-sinusoidal vascular disorder (PSVD) is one of the common causes of portal hypertension and has overlapping features with early cirrhosis. The differentiation of PSVD from cirrhosis requires a liver biopsy, which is invasive and has potential complications. This systematic review aimed at summarizing the current evidence on the performance of noninvasive modalities for differentiating PSVD from cirrhosis.

METHODS

A comprehensive search of electronic databases of MEDLINE, Embase, and Scopus was conducted from 2000 to October 2022 for the studies comparing the elastographic and radiological features of PSVD and cirrhosis, using liver biopsy as the gold standard.

RESULTS

A total of 12 studies were included in the systematic review. Transient elastography (TE) as a modality was studied in five studies, MR elastography (MRE) in two, contrast CT in two, Contrast CT and MRI in two, and ARFI in only one. Both TE and MRE showed a significantly lower liver stiffness measurement and a higher splenic stiffness measurement with a higher SSM/LSM ratio with PSVD, compared to cirrhosis. Among the radiological features, focal nodular hyperplasia-like lesions, portal vein abnormalities (intrahepatic and extrahepatic), and a larger spleen size favored a diagnosis of PSVD. In contrast, surface nodularity and atrophy of segment IV with a segment I hypertrophy favored a diagnosis of cirrhosis.

CONCLUSION

Elastography and cross-sectional imaging can help differentiate PSVD from early cirrhosis with good accuracy. Further studies are required to assess the diagnostic role of a combination of both modalities.

Endoscopic ultrasound-guided portal pressure gradient measurement in managing portal hypertension

Portal hypertension (PH) is still a challenging clinical condition due to its silent manifestations in the early stage and needs to be measured accurately for early detection. Hepatic vein pressure gradient measurement has been considered as the gold standard measurement for PH; however, it needs special skill, experience, and high expertise. Recently, there has been an innovative development in using endoscopic ultrasound (EUS) for the diagnosis and management of liver diseases, including portal pressure measurement, which is commonly known as EUS-guided portal pressure gradient (EUS-PPG) measurement. EUS-PPG measurement can be performed concomitantly with EUS evaluation for deep esophageal varices, EUS-guided liver biopsy, and EUS-guided cyanoacrylate injection. However, there are still major issues, such as different etiologies of liver disease, procedural training, expertise, availability, and cost-effectiveness in several situations with regard to the standard management.

Increased sinusoidal pressure impairs liver endothelial mechanosensing, uncovering novel biomarkers of portal hypertension

Background & Aims

Portal hypertension (PH) is a frequent and severe clinical syndrome associated with chronic liver disease. Considering the mechanobiological effects of hydrostatic pressure and shear stress on endothelial cells, we hypothesised that PH might influence the phenotype of liver sinusoidal endothelial cells (LSECs) during disease progression. The aim of this study was to investigate the effects of increased hydrodynamic pressure on LSECs and to identify endothelial-derived biomarkers of PH.

Methods

Primary LSECs were cultured under normal or increased hydrodynamic pressure within a pathophysiological range (1 vs. 12 mmHg) using a microfluidic liver-on-a-chip device. RNA sequencing was used to identify pressure-sensitive genes, which were validated in liver biopsies from two independent cohorts of patients with chronic liver disease with PH (n = 73) and participants without PH (n = 23). Biomarker discovery was performed in two additional independent cohorts of 104 patients with PH and 18 patients without PH.

Results

Transcriptomic analysis revealed marked deleterious effect of pathological pressure in LSECs and identified chromobox 7 (CBX7) as a key transcription factor diminished by pressure. Hepatic CBX7 downregulation was validated in patients with PH and significantly correlated with hepatic venous pressure gradient. MicroRNA 181a-5p was identified as pressure-induced upstream regulator of CBX7. Two downstream targets inhibited by CBX7, namely, E-cadherin (ECAD) and serine protease inhibitor Kazal-type 1 (SPINK1), were found increased in the bloodstream of patients with PH and were highly predictive of PH and clinically significant PH.

Conclusions

We characterise the detrimental effects of increased hydrodynamic pressure on the sinusoidal endothelium, identify CBX7 as a pressure-sensitive transcription factor, and propose the combination of two of its reported products as biomarkers of PH.

Impact and Implications

Increased pressure in the portal venous system that typically occurs during chronic liver disease (called portal hypertension) is one of the main drivers of related clinical complications, which are linked to a higher risk of death. In this study, we found that pathological pressure has a harmful effect on liver sinusoidal endothelial cells and identified CBX7 as a key protein involved in this process. CBX7 regulates the expression of E-cadherin and SPINK1, and consequently, measuring these proteins in the blood of patients with chronic liver disease allows the prediction of portal hypertension and clinically significant portal hypertension.

Imaging features facilitate diagnosis of porto-sinusoidal vascular disorder

OBJECTIVES

Porto-sinusoidal vascular disorder (PSVD) is a recently defined vascular liver disease. Since diagnosis remains challenging, we aimed to evaluate radiological features that are distinct between PSVD and cirrhosis.

METHODS

Clinical, laboratory, and radiological parameters (CT/MRI) of patients with histologically-confirmed PSVD vs. cirrhosis vs. non-cirrhotic parenchymal liver disease were retrospectively evaluated.

RESULTS

Sixty-three PSVD, 155 cirrhosis, and 41 non-cirrhotic patients were included. As compared to cirrhosis, PSVD patients were younger and had lower HVPG, liver stiffness, and MELD. Routine clinical and imaging findings indicative of portal hypertension were similarly common. Intrahepatic portal tract abnormalities (49% vs. 15%; p < 0.001), FNH-like lesions (30% vs. 1%; p < 0.001), and abnormal liver morphology defined as peripheral parenchymal atrophy and compensatory hypertrophy of central segments (32% vs. 7%; p < 0.001) were significantly more common in PSVD patients. Hypertrophy of segment I (70% vs. 84%; p = 0.019), atrophy of segment IV (24% vs. 47%; p = 0.001), and nodular liver surface (22% vs. 89%; p < 0.001) were more common in patients with cirrhosis. In patients with gadoxetic acid-enhanced MRI, we identified the distinct imaging feature of "periportal hyperintensity" in the hepatobiliary phase (HBP) in 42% of patients with PSVD (14/33) vs. 1% in cirrhosis (1/95) vs. 0% in non-cirrhotic controls (0/41); p < 0.001).

CONCLUSIONS

Diagnosis of PSVD must be considered in younger patients presenting with clinical features of portal hypertension, portal tract abnormalities, and FNH-like lesions on CT/MRI. 'Periportal hyperintensity' in the HBP of gadoxetic acid-enhanced MRI was identified as a specific radiological feature of PSVD.

KEY POINTS

• Cross-sectional imaging can provide essential information to identify patients with porto-sinusoidal vascular disorder (PSVD). • Intrahepatic portal tract abnormalities, FNH-like lesions, and abnormal liver morphology are common in PSVD patients. • Periportal hyperintensity on the hepatobiliary phase of gadoxetic acid-enhanced MRI seems to be specific for patients with PSVD.

Benign Hepatic Nodules in Patients With Primary Extrahepatic Portal Vein Obstruction: Clinical and Magnetic Resonance Imaging Features

Background/objective

To retrospectively evaluate the magnetic resonance imaging (MRI) features of benign hepatic nodules in patients with extrahepatic portal vein obstruction (EHPVO) and assess predictable features for their development.

Methods

This retrospective observational study included 18 diagnosed patients of EHPVO who underwent contrast enhanced abdominal MRI at our Institute between June 2016 and May 2017, and who could be followed up for at least two years. The patients with liver nodules formed the study group (n = 8; 4 males, 4 females; mean age: 26.1 ± 10.9 years) and patients without liver nodules were controls (n = 10; 3 males, 7 females; mean age: 24.2 ± 15.1 years). Liver nodules were confirmed as benign by either biopsy or stability on follow up imaging. MRI features of liver nodules were assessed. Clinical details and imaging data of the study group were compared with controls to assess predictable features.

Results

There was no statistically significant difference in age, gender, clinical characteristics and upper gastrointestinal endoscopic findings between the study and control groups. The size of the lienorenal collateral, left renal vein and superior mesenteric vein were significantly larger in the study group (P < 0.05). In the study group, the majority had multiple hepatic nodules with most of them being isointense on T1 (18/35; 51.4%) and T2-weighted images (16/35; 45.7%) and showing restriction of diffusion (21/35; 60%). All (n = 35) lesions showed arterial phase hyperenhancement and none showed washout in the venous phase. The patients in the control group did not develop any liver nodules during the follow-up period.

Conclusion

Liver nodules in patients with EHPVO are likely to be benign and have characteristic MRI features. Significantly larger lienorenal collateral, left renal vein and superior mesenteric vein were associated with the development of these nodules.

Pathological and imaging features of idiopathic non-cirrhotic portal hypertension

Idiopathic non-cirrhotic portal hypertension (INCPH), a kind of portal sinus vascular disease with unknown etiology, is characterized by the presence of clinical signs and symptoms of portal hypertension (PH) in the absence of liver cirrhosis or known risk factors accountable for PH. It has an extremely high rate of initial misdiagnosis and underdiagnosis. Liver biopsy is the only way to make a definitive diagnosis. Non-invasive modalities, such as CT imaging, are becoming a hot topic of interest in recent years. This article summarizes the pathological and CT/MRI features of INCPH and the key points of differentiation from cirrhosis, to improve clinicians' understanding of INCPH and reduce the rate of initial misdiagnosis and missed diagnoses.

Porto-Sinusoidal Vascular Disease: A Pediatric Study of 30 Patients

OBJECTIVES

Porto-sinusoidal vascular disease (PSVD) refers to a broad spectrum of histological lesions and phenotypic expressions. There are only a few reported pediatric cases in the literature. The primary outcomes of this study were to describe the phenotype of children with PSVD, to specify their mode of presentation and their clinical, biological, histological, and radiological characteristics as well as to identify their underlying etiologies.

METHODS

This is a descriptive, retrospective, and monocentric study of children followed at our reference center for rare vascular liver diseases.

RESULTS

Our study included 30 children ages 2months to 17.4years at the time of diagnosis. in most cases, the diagnosis was made incidentally without manifestation of any clinical symptom but rather on the finding of splenomegaly on physical examination (n = 9) or biological abnormalities (n = 13). In the other cases, the main presenting symptom was an upper gastrointestinal bleeding (n = 6). At the first visit, liver laboratory values were either normal (37%) or slightly disturbed. Anemia and/or thrombocytopenia associated with hypersplenism were found in 60% of patients. Liver biopsy was necessary for diagnosis. A total of 80% of cases had no identified etiology. After a median follow-up of 4.5 years, 33% had not developed portal hypertension (PHT) and we reported the first pediatric case of hepatocellular carcinoma in PSVD children.

CONCLUSIONS

PSVD is responsible for nonspecific symptomatology with variable evolution sometimes marked by serious complications requiring invasive treatments or even liver transplantation. Regular monitoring is essential to prevent, detect, and treat complications.

Non-tuberculosis extensive abdominal lymph node calcification leading to portal hypertension with esophageal and gastric variceal bleeding: a rare case report

Background

Calcification of abdominal lymph node is a common clinical phenomenon, but it is extremely rare to cause serious adverse clinical outcomes. In the present case, the ruptured hemorrhage of the oesophagogastric fundic varices occurred as a result of portal hypertension due to compression of the portal vein by calcified lymph nodes. The patient was treated with medication, interventional therapy, endoscopic therapy, and surgery, respectively and the four different treatment options for the bleeding are worth summarizing. The etiology of this case is extremely rare and is the first to be reported in the world.

Case presentation

A 32-year-old male patient with no apparent causes of sudden onset of vomiting of blood, the patient underwent four different treatment methods to stop the hemorrhage. The combined diagnosis of whole abdomen enhanced CT and angiography was calcified abdominal lymph nodes compressing the portal vein, leading to portal hypertension and resulting in esophageal and gastric variceal bleeding. Postoperatively, a biopsy of the caseous tubercular tissue of the abdominal wall observed intraoperatively was performed and the biopsy did not show a tubercular component. Therefore, the extensive intra-abdominal lymph node calcification was not associated with tuberculosis. The patient's bleeding ceased after surgery.

Conclusion

This case has improved the clinician's understanding of the etiology of non-cirrhotic portal hypertension. Based on this, and with this case, the differences between various hemostatic measures were studied in depth.

Impact of vascular liver disease on the menstrual cycle and metabolic status in premenopausal women

BACKGROUND

Vascular liver disease (VLD) are rare liver diseases, which affect women at reproductive ages. Main complications are bleeding (portal hypertension, thrombopenia or anticoagulation related) and thromboembolism. Failure of liver function can occur. Thus endocrine abnormalities management and contraception are challenging.

PURPOSE

to evaluate the impact on the menstrual cycles and related endocrine abnormalities in women with VLD and respective roles of liver function and portal hypertension.

STUDY DESIGN

This was a single-center observational cohort study. Forty-seven premenopausal women with vascular liver disease were included for endocrine and gynecological assessments. Endocrine evaluation was performed at inclusion. Tolerance of contraception was followed up and assessed at 3 and 12 months.

PARTICIPANTS, SETTING, METHODS

Forty-seven women (aged 16-50) followed in a Reference Center for Liver Vascular Disease between February 2009 and November 2016 were included and addressed for gynecological and endocrinological management. Twenty-five women had extrahepatic portal vein obstruction, 17 had Budd Chiari Syndrome and five had a porto-sinusoidal vascular disease. We explored gonadotropin at baseline and after GnRH, testosterone, sex hormone binding globulin (SHBG), androstenedione, GH axis and glucose metabolism. All women underwent pelvic ultrasonography.

RESULTS

Vascular liver disease was associated with abnormal menstrual cycles in 53% of the women and clinical and/or biological hyperandrogenism and/or a polycystic ovary morphology was identified in 38%. Portal hypertension was correlated to higher testosterone levels (P = 0.04), whereas higher elevated levels SHBG in 28%, correlated with liver failure (P = 0.01). Sixteen had glucose intolerance profile or diabetes. IGF-1 levels were highly correlated with hepatic failure. Abnormal uterine bleeding occurred in 21% of women, 87% of which were due to gynecological pathologies revealed by anticoagulant treatment. Progestin contraception was well tolerated and helped to control bleeding.

CONCLUSION AND IMPLICATIONS

endocrine abnormalities, prior described in association with cirrhosis, are also identified in patients with vascular liver disease, and require specific management. Glucose intolerance profile is frequent, further studies are needed to assess significant consequences on cardio-vascular system.

Idiopathic Non-Cirrhotic Portal Hypertension and Porto-Sinusoidal Vascular Disease: Review of Current Data

Idiopathic non-cirrhotic portal hypertension (INCPH) is a clinicopathologic disease entity characterized by the presence of clinical signs and symptoms of portal hypertension (PH) in the absence of liver cirrhosis or known risk factors accountable for PH. Multiple hematologic, immune-related, infectious, hereditary and metabolic risk factors have been associated with this disorder. Still, the exact etiopathogenesis is largely unknown. The recently proposed porto-sinusoidal vascular disease (PSVD) scheme broadens the spectrum of the disease by also including patients without clinical PH who are found to have similar histopathologic findings on core liver biopsies. Three histomorphologic lesions have been identified as specific for PSVD to include obliterative portal venopathy, nodular regenerative hyperplasia and incomplete septal cirrhosis/fibrosis. However, these findings are often subtle, under-recognized and subjective with low interobserver agreement among pathologists. Additionally, the natural history of the subclinical forms of the disease remains unexplored. The clinical course is more favorable compared to cirrhosis patients, especially in the absence of clinical PH or liver dysfunction. There are no universally accepted guidelines in regard to diagnosis and treatment of INCPH/PSVD. Hence, this review emphasizes the need to raise awareness of this entity by highlighting its complex pathophysiology and clinicopathologic associations. Lastly, formulation of standardized diagnostic criteria with clinical validation is necessary to avoid misclassifying vascular diseases of the liver and to develop and implement targeted therapeutic strategies.

Schistosomiasis Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease of the lung blood vessels that results in right heart failure. PAH is thought to occur in about 5% to 10% of patients with hepatosplenic schistosomiasis, particularly due to S. mansoni. The lung blood vessel injury may result from a combination of embolization of eggs through portocaval shunts into the lungs causing localized Type 2 inflammatory response and vessel remodeling, triggering of autonomous pathology that becomes independent of the antigen, and high cardiac output as seen in portopulmonary hypertension. The condition is likely underdiagnosed as there is little systematic screening, and risk factors for developing PAH are not known. Screening is done by echocardiography, and formal diagnosis requires invasive right heart catheterization. Patients with Schistosoma-associated PAH show reduced functional capacity and can be treated with pulmonary vasodilators, which improves symptoms and may improve survival. There are animal models of this disease that might help in understanding disease pathogenesis and identify novel targets to screen and treatment. Pathogenic mechanisms include Type 2 immunity and activation and signaling in the TGF-β pathway. There are still major uncertainties regarding Schistosoma-associated PAH development, course and treatment.