Role of calreticulin mutations in the aetiological diagnosis of splanchnic vein thrombosis

Etiology and Risk Factors for Splanchnic Vein Thrombosis in Non-Cirrhotic, Non-Neoplastic Patients: A Narrative Review

Splanchnic vein thrombosis (SVT) is a heterogeneous group of disorders affecting the portal, mesenteric, splenic, and hepatic veins. While frequently associated with liver cirrhosis and malignancy, SVT also occurs in non-cirrhotic, non-neoplastic patients. This narrative review evaluates the epidemiology and risk factors for SVT in this population. The prevalence and incidence of SVT in non-cirrhotic, non-neoplastic patients remain incompletely characterized, with estimates varying widely across studies. The clinical significance of SVT relates to potential complications, including intestinal ischemia, portal hypertension, and a possible underlying systemic disorder. Risk factors for SVT can be categorized into local abdominal conditions, thrombophilias, and systemic disorders. Local factors include inflammatory bowel disease, pancreatitis, abdominal surgery, and trauma. Thrombophilias, both inherited and acquired, are significant contributors to SVT risk. Systemic conditions associated with SVT include autoimmune disorders, pregnancy, hematological diseases, and infections. The complex interplay of these risk factors highlights the need for a comprehensive evaluation of SVT patients. Early recognition and management of these conditions can prevent potentially life-threatening complications and guide decisions regarding anticoagulation and long-term follow-up.

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.

Obliteration of liver sinusoids through platelet aggregates associated to extramedullary haematopoiesis in myeloid neoplasms

Herein is reported a series of five patients with myeloid neoplasms presenting hepatic complications in whose liver biopsy revealed obstruction of sinusoids by platelet aggregates associated to liver extramedullary haematopoiesis. Indication of liver biopsies was jaundice, unexplained hepatomegaly or portal hypertension. Haematological disorders were classified according to the World Health Organisation. Molecular profile was established in all cases as well as grade of liver extramedullary haematopoiesis and myelofibrosis. The patients were four men and one woman aged from 50 to 82 years. Two patients had myeloproliferative neoplasm (triple negative primary myelofibrosis and JAK2-mutated essential thrombocytopenia), two patients had unclassifiable myelodysplastic/myeloproliferative neoplasm and one patient had chronic myelomonocytic leukaemia type 1. Liver biopsies revealed platelet aggregates occluding sinusoids in association with extramedullary haematopoiesis grade 1 in one patient, grade 2 in two patients and grade 3 in two patients. Two of these patients presented co-existing liver fibrosis due to chronic alcoholic consumption and ischemic heart failure. These five patients died from 2 to 23 months after liver biopsy due to acute myeloblastic leukaemia (three patients), portal hypertension (one patient) or other causes (acute heart failure). Intrahepatic sinusoidal microthromboses through platelet aggregates might cause portal hypertension or liver deficiency in patients with myeloid neoplasms, independently of JAK2 mutational status and grade of extramedullary haematopoiesis.

Abdominal surgery in patients with chronic noncirrhotic extrahepatic portal vein obstruction: A multicenter retrospective study

BACKGROUND AND AIMS

In patients with noncirrhotic chronic extrahepatic portal vein obstruction (EHPVO), data on the morbimortality of abdominal surgery are scarce.

APPROACH AND RESULTS

We retrospectively analyzed the charts of 76 patients (78 interventions) with EHPVO undergoing abdominal surgery within the Vascular Disease Interest Group network. Fourteen percent of the patients had ≥1 major bleeding (unrelated to portal hypertension) and 21% had ≥1 Dindo-Clavien grade ≥3 postoperative complications within 1 month after surgery. Fifteen percent had ≥1 portal hypertension-related complication within 3 months after surgery. Three patients died within 12 months after surgery. An unfavorable outcome (ie, ≥1 abovementioned complication or death) occurred in 37% of the patients and was associated with a history of ascites and with nonwall, noncholecystectomy surgical intervention: 17% of the patients with none of these features had an unfavorable outcome, versus 48% and 100% when one or both features were present, respectively. We then compared 63/76 patients with EHPVO with 126 matched (2:1) control patients without EHPVO but with similar surgical interventions. As compared with control patients, the incidence of major bleeding ( p <0.001) and portal hypertension-related complication ( p <0.001) was significantly higher in patients with EHPVO, but not that of grade ≥3 postoperative complications nor of death. The incidence of unfavorable postoperative outcomes was significantly higher in patients with EHPVO than in those without (33% vs. 18%, p =0.01).

CONCLUSIONS

Patients with EHPVO are at high risk of major perioperative or postoperative bleeding and postoperative complications, especially in those with ascites or undergoing surgery other than wall surgery or cholecystectomy.

Current concepts in the management of non-cirrhotic non-malignant portal vein thrombosis

Non-cirrhotic non-malignant portal vein thrombosis (NCPVT) is an uncommon condition characterised by thrombosis of the portal vein, with or without extension into other mesenteric veins, in the absence of cirrhosis or intra-abdominal malignancy. Complications can include intestinal infarction, variceal bleeding and portal biliopathy. In this article, we address current concepts in the management of NCPVT including identification of risk factors, classification and treatment, and review the latest evidence on medical and interventional management options.

Portal Vein Thrombosis: State-of-the-Art Review

Background: Portal vein thrombosis (PVT) is a rare disease with an estimated incidence of 2 to 4 cases per 100,000 inhabitants. The most common predisposing conditions for PVT are chronic liver diseases (cirrhosis), primary or secondary hepatobiliary malignancy, major infectious or inflammatory abdominal disease, or myeloproliferative disorders. Methods: PVT can be classified on the basis of the anatomical site, the degree of venous occlusion, and the timing and type of presentation. The main differential diagnosis of PVT, both acute and chronic, is malignant portal vein invasion, most frequently by hepatocarcinoma, or constriction (typically by pancreatic cancer or cholangiocarcinoma). Results: The management of PVT is based on anticoagulation and the treatment of predisposing conditions. The aim of anticoagulation in acute thrombosis is to prevent the extension of the clot and enable the recanalization of the vein to avoid the development of complications, such as intestinal infarction and portal hypertension. Conclusions: The treatment with anticoagulant therapy favors the reduction of portal hypertension, and this allows for a decrease in the risk of bleeding, especially in patients with esophageal varices. The anticoagulant treatment is generally recommended for at least three to six months. Prosecution of anticoagulation is advised until recanalization or lifelong if the patient has an underlying permanent pro-coagulant condition that cannot be corrected or if there is thrombosis extending to the mesenteric veins.

The molecular landscape of myeloproliferative neoplasms associated with splanchnic vein thrombosis: Current perspective

BCR::ABL1-negative myeloproliferative neoplasms (MPNs) are classically represented by polycythemia vera, essential thrombocythemia, and primary myelofibrosis. BCR::ABL1-negative MPNs are significantly associated with morbidity and mortality related to an increased risk of thrombo-hemorrhagic events. They show a consistent association with splanchnic vein thrombosis (SVT), either represented by the portal, mesenteric or splenic vein thrombosis, or Budd-Chiari Syndrome. SVT is also a frequent presenting manifestation of MPN. MPNs associated with SVT show a predilection for younger women, high association with JAK2V617F mutation, low JAK2V617F variant allele frequency (generally <10 %), and low rates of CALR, MPL, or JAK2 exon 12 mutations. Next-Generation Sequencing techniques have contributed to deepening our knowledge of the molecular landscape of such cases, with potential diagnostic and prognostic implications. In this narrative review, we analyze the current perspective on the molecular background of MPN associated with SVT, pointing as well future directions in this field.

Insight into increased risk of portal vein thrombosis in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the leading chronic liver diseases with increased morbidity and mortality rates for extrahepatic diseases (including cardiovascular disease, portal vein thrombosis, etc.). There is an increased risk of thrombosis in both the portal and systemic circulation in patients with NAFLD, independent of traditional liver cirrhosis. However, increased portal pressure, the most critical factor, is frequently observed in NAFLD patients, predisposing them to portal vein thrombosis (PVT). It has been reported that there is an 8.5% incidence of PVT among patients with non-cirrhotic NAFLD in a prospective cohort study. Based on the prothrombotic status of NAFLD itself, patients combined with cirrhosis may accelerate the development of PVT and lead to a poor prognosis. Moreover, PVT has been shown to complicate the procedure and adversely affect the outcome during liver transplantation surgery. NAFLD is in a prothrombotic state, and its underlying mechanisms have not been fully understood so far. Particularly noteworthy is that gastroenterologists currently overlook the higher risk of PVT in NAFLD. We investigate the pathogenesis of NAFLD complicated with PVT from the perspective of primary, secondary, and tertiary hemostasis, and also summarize relevant studies in humans. Some treatment options that may affect NAFLD and its PVT are also explored to improve patient-oriented outcomes.

Pathological and genomic features of myeloproliferative neoplasms associated with splanchnic vein thrombosis in a single-center cohort

Here, we reviewed clinical-morphological data and investigated mutational profiles by NGS in a single-center series of 58 consecutive MPN-SVT patients admitted to our hospital between January 1979 and November 2021. We identified 15.5% of PV, 13.8% of ET, 34.5% of PMF, 8.6% of SMF and 27.6% of MPN-U. Most cases (84.5%) carried JAK2V617F mutation, while seven patients were characterized by other molecular markers, namely MPL in four and CALR mutations in three cases. NGS was performed in 54 (93.1%) cases: the most frequent additional mutations were found in TET2 (27.8%) and DNMT3A (16.7%) genes, whereas 25 (46.3%) patients had no additional mutation. Cases with JAK2V617F homozygosity had a higher median number of additional mutations than those with low allele burden. More importantly, all cases of leukemic evolution were characterized by a higher median number of co-mutations, and a co-mutational pattern of high-risk lesions, such as truncating mutations of ASXL1, bi-allelic TP53 loss, and CSMD1 mutations. Nevertheless, no difference was found between cases with and without additional somatic mutations regarding fibrotic progression, SVT recurrence, other thrombo-hemorrhagic complications, or death. After a median follow-up of 7.1 years, ten deaths were recorded; fibrotic progression/leukemic evolution was ascertained in one (1.7%) and six (10.3%) patients, respectively, while 22 (37.9%) patients suffered from recurrent thrombosis. In conclusion, our data underline the importance of using NGS analysis in the management of MPN-related SVT as it can support the MPN diagnosis, particularly in "triple-negative" cases, and provide additional information with potential consequences on prognosis and therapeutic strategies.

Management of splanchnic vein thrombosis

The expression splanchnic vein thrombosis encompasses Budd-Chiari syndrome and portal vein thrombosis. These disorders have common characteristics: they are both rare diseases which can cause portal hypertension and its complications. Budd-Chiari syndrome and portal vein thrombosis in the absence of underlying liver disease share many risk factors, among which myeloproliferative neoplasms represent the most common; a rapid comprehensive work-up for risk factors of thrombosis is needed in these patients. Long-term anticoagulation is indicated in most patients. Portal vein thrombosis can also develop in patients with cirrhosis and in those with porto-sinusoidal vascular liver disease. The presence and nature of underlying liver disease impacts the management of portal vein thrombosis. Indications for anticoagulation in patients with cirrhosis are growing, while transjugular intrahepatic portosystemic shunt is now a second-line option. Due to the rarity of these diseases, studies yielding high-grade evidence are scarce. However, collaborative studies have provided new insight into the management of these patients. This article focuses on the causes, diagnosis, and management of patients with Budd-Chiari syndrome, portal vein thrombosis without underlying liver disease, or cirrhosis with non-malignant portal vein thrombosis.

Molecular Genetics of Thrombotic Myeloproliferative Neoplasms: Implications in Precision Oncology

Classical BCR-ABL-negative myeloproliferative neoplasms (MPN) include polycythaemia vera, essential thrombocythaemia, and primary myelofibrosis. Unlike monogenic disorders, a more complicated series of genetic mutations are believed to be responsible for MPN with various degrees of thromboembolic and bleeding complications. Thrombosis is one of the early manifestations in patients with MPN. To date, the driver genes responsible for MPN include JAK2, CALR, MPL, TET2, ASXL1, and MTHFR. Affords have been done to elucidate these mutations and the incidence of thromboembolic events. Several lines of evidence indicate that mutations in JAK2, MPL, TET2 and ASXL1 gene and polymorphisms in several clotting factors (GPIa, GPIIa, and GPIIIa) are associated with the occurrence and prevalence of thrombosis in MPN patients. Some polymorphisms within XRCC1, FBG, F2, F5, F7, F12, MMP9, HPA5, MTHFR, SDF-1, FAS, FASL, TERT, ACE, and TLR4 genes may also play a role in MPN manifestation. This review aims to provide an insightful overview on the genetic perspective of thrombotic complications in patients with MPN.

Portal Venous Thrombosis in Alcoholic Hepatitis: A Relatively Unknown Association

Portal venous thrombosis (PVT) is a rare diagnosis in the general population. However, it is seen in patients with liver cirrhosis with an estimated prevalence ranging from 0.6% to 26%. Literature reports that about one-third of PVT cases have an unknown etiology. Identifying the precipitating factors implicated in the development of PVT is imperative as it may help guide therapy. Although the association between liver cirrhosis and PVT has been well established in current literature, there continues to be a relative lack of awareness of alcoholic hepatitis (AH) as a risk factor for PVT. Identifying AH as a trigger for thrombosis can help avoid extended anticoagulation and its complications. In the following case report and brief review, we discuss an uncommon case of a 33-year-old male who came to the hospital emergency department with complaints of nauseousness, abdominal discomfort, and yellow discoloration. Lab investigations showed transaminitis. The diagnosis of AH was established, and an abdominal duplex ultrasound revealed PVT. Heparin drip was started as a part of treatment, which improved his abdominal discomfort. He was eventually discharged on apixaban 5 mg twice daily for 3 months and a repeat abdominal duplex ultrasound in 3 months to check for the resolution of the PVT.

Incidence and factors predictive of recurrent thrombosis in people with non-cirrhotic portal vein thrombosis

BACKGROUND & AIMS

Clinical guidelines do not recommend long-term anticoagulation in non-cirrhotic splanchnic vein thrombosis (NC-SVT) without underlying thrombophilia because it is assumed that there is a very low risk of recurrent thrombosis (RT). Our first aim was to describe the incidence of RT in people with NC-SVT without an indication for long-term anticoagulation. The second aim was to identify RT risk factors and afterwards verify them in a validation cohort.

METHODS

This is a multicentre, retrospective observational study evaluating risk factors for RT in 64 people with NC-SVT of idiopathic/local factor aetiology. In a subgroup of 48 individuals, the potential value of additional thrombophilic parameters to predict RT was analysed. Findings were validated in 70 individuals with idiopathic/local factor NC-SVT.

RESULTS

Of the 64 participants in the training cohort, 17 (26%) presented splanchnic and/or extrasplanchnic RT (overall-RT) during follow-up (cumulative incidence: 2, 10, 19, and 34% at 1, 2, 5, and 10 years, respectively). In addition, 53% of people with splanchnic RT were asymptomatic. No clinical or biochemical parameters predicted overall-RT. However, in the 48 people with an additional comprehensive thrombophilic study, factor VIII ≥150% was the only independent factor predicting overall-RT (hazard ratio 7.10, 95% CI 2.17-23.17, p <0.01). In the validation cohort, 19 individuals (27%) presented overall-RT, and it was also independently predicted by factor VIII >150% (hazard ratio 3.71, 95% CI 1.31-10.5, p <0.01). The predictive value of factor VIII was confirmed in both people with idiopathic/local factor aetiology associated NC-SVT.

CONCLUSIONS

People with idiopathic/local factor NC-SVT are at risk of overall-RT. Splanchnic RT can be asymptomatic and requires screening for its detection. Values of factor VIII ≥150% may help identify individuals at high risk of overall-RT who could benefit from long-term anticoagulation.

IMPACT AND IMPLICATIONS

People with idiopathic/isolated local factor non-cirrhotic portal vein thrombosis were previously thought to be at minimal risk of re-thrombosis and therefore did not receive scheduled follow-up. The results of this study are of special interest for hepatologists treating people with non-cirrhotic splanchnic thrombosis, as they show a 25% incidence of re-thrombosis and support the close follow-up of people with factor VIII >150% to ensure the early identification of new thrombotic events.

Multicenter study on recent portal venous system thrombosis associated with cytomegalovirus disease

BACKGROUND & AIMS

Recent non-malignant non-cirrhotic portal venous system thrombosis (PVT) is a rare condition. Among risk factors for PVT, cytomegalovirus (CMV) disease is usually listed based on a small number of reported cases. The aim of this study was to determine the characteristics and outcomes of PVT associated with CMV disease.

METHODS

We conducted a French multicenter retrospective study comparing patients with recent PVT and CMV disease ("CMV positive"; n = 23) to patients with recent PVT for whom CMV testing was negative ("CMV negative"; n = 53) or unavailable ("CMV unknown"; n = 297).

RESULTS

Compared to patients from the "CMV negative" and "CMV unknown" groups, patients from the "CMV positive" group were younger, more frequently had fever, and had higher heart rate, lymphocyte count and serum ALT levels (p ≤0.01 for all). The prevalence of immunosuppression did not differ between the 3 groups (4%, 4% and 6%, respectively). Extension of PVT was similar between the 3 groups. Thirteen out of 23 "CMV positive" patients had another risk factor for thrombosis. Besides CMV disease, the number of risk factors for thrombosis was similar between the 3 groups. Heterozygosity for the prothrombin G20210A gene variant was more frequent in "CMV positive" patients (22%) than in the "CMV negative" (4%, p = 0.01) and "CMV unknown" (8%, p = 0.03) groups. Recanalization rate was not influenced by CMV status.

CONCLUSIONS

In patients with recent PVT, features of mononucleosis syndrome should raise suspicion of CMV disease. CMV disease does not influence thrombosis extension nor recanalization. More than half of "CMV positive" patients have another risk factor for thrombosis, with a particular link to the prothrombin G20210A gene variant.

LAY SUMMARY

Patients with cytomegalovirus (CMV)-associated portal venous system thrombosis have similar thrombosis extension and evolution as patients without CMV disease. However, patients with CMV-associated portal venous system thrombosis more frequently have the prothrombin G20210A gene variant, suggesting that these entities act synergistically to promote thrombosis.

Risk of non-tumoural portal vein thrombosis in patients with HCV-induced cirrhosis after sustained virological response

BACKGROUND & AIMS

Sustained virological response (SVR) to direct-acting antivirals ameliorates portal hypertension, improves hepatic function and may reverse the procoagulant state observed in patients with cirrhosis. However, an unexpected incidence of portal vein thrombosis (PVT) immediately after antiviral therapy has recently been reported. Therefore, we analysed the long-term impact of SVR on the development of non-tumoural PVT.

METHODS

Our study comprised of two well-characterized prospective cohorts (hepatitis C virus '(HCV)-Cured': n = 354/'HCV-Active': n = 179) of patients with HCV cirrhosis who underwent standardized ultrasound surveillance. In the main analysis, the event of interest was de novo non-tumoural PVT and events known to modify its natural history (orthotopic liver transplantation, transjugular intrahepatic portosystemic shunt, death, tumoural PVT and anticoagulation) were considered as competing risk. Adjusted models were built using propensity scores for baseline covariates. Moreover, predictive factors were investigated by conventional multivariate analysis.

RESULTS

Ten (2.8%) patients in the 'HCV-Cured' cohort developed a non-tumoural PVT during a median follow-up of 37.1 months, while 8 (4.5%) patients in the 'HCV-Active' cohort were diagnosed with non-tumoural PVT during a median follow-up of 42.2 months. High Child-Pugh score was the only independent risk factor for non-tumoural PVT development and stage A patients were at low risk. Importantly, HCV cure did not decrease the risk of non-tumoural PVT in inverse probability of treatment-weighted (IPTW) analysis (subdistribution hazard ratio: 1.31 (95% confidence interval [95% CI]: 0.43-3.97); P = .635). In contrast, SVR was associated with a substantial reduction in mortality (IPTW-adjusted sHR: 0.453 [95% CI: 0.287-0.715]; P < .001).

CONCLUSIONS

The risk of non-tumoural PVT persists after HCV cure in patients with cirrhosis, despite improving survival. Even after aetiological cure, severity of liver disease remains the main determinant of non-tumoural PVT development.

Budd-Chiari syndrome: consensus guidance of the Asian Pacific Association for the study of the liver (APASL)

Budd Chiari syndrome (BCS) is a diverse disease with regard to the site of obstruction, the predisposing thrombophilic disorders and clinical presentation across the Asia-Pacific region. The hepatic vein ostial stenosis and short segment thrombosis are common in some parts of Asia-Pacific region, while membranous obstruction of the vena cava is common in some and complete thrombosis of hepatic veins in others. Prevalence of myeloproliferative neoplasms and other thrombophilic disorders in BCS varies from region to region and with different sites of obstruction. This heterogeneity also raises several issues and dilemmas in evaluation and approach to management of a patient with BCS. The opportunity to recanalize hepatic vein in patients with hepatic vein ostial stenosis or inferior vena cava stenting or pasty among those membranous obstruction of the vena cava is a unique opportunity in the Asia-Pacific region to restore hepatic outflow closely mimicking physiology. In order to address these issues arising out of the diversity as well as the unique features in the region, the Asia Pacific Association for Study of Liver has formulated these guidelines for clinicians.

Portal vein thrombosis: A concise review (Review)

Portal vein thrombosis (PVT) is a frequent complication in cirrhotic patients, but it may also exist as a basic vascular condition even without any liver damage. Local and systemic factors play a significant role in the pathogenesis of PVT; yet, in practice, more than one factor may be identified. PVT can be considered a result of liver fibrosis and hepatic insufficiency. The JAK2 mutation has been accepted as a factor producing PVT. In general, the anticoagulants are recommended but this therapy should be used carefully in treating patients that associate coagulopathy or thrombocytopenia and esophageal varices. Acute PVT without bowel infarction has a good prognosis. In liver cirrhosis, the mortality due to hemorrhage is higher than in chronic PVT. Therefore, for the patients with PVT, the survival rate is decreased by 55% in two years, due to hepatic insufficiency. Regarding the treatment, LMWH (low molecular weight heparine) is the most utilized in patients with cirrhosis, non-malignancies, infections, or those who are awaiting a liver transplant. DOACs (direct-acting oral anticoagulants) may be used in the rest of the medical conditions, being safe and equal to LMWH.

De novo Portal Vein Thrombosis in Non-Cirrhotic Non-Alcoholic Fatty Liver Disease: A 9-Year Prospective Cohort Study

Background and Aims: Approximately 30-40% of portal vein thrombosis (PVT) remains of unknown origin. The association between non-alcoholic fatty liver disease (NAFLD) and PVT is a matter of debate. This study aimed to investigate the association between PVT and NAFLD. Methods: We included 94 out of 105 consecutive NAFLD patients in this prospective cohort study in addition to 94 from the healthy control group. We evaluated biochemical, clinical, immunological, and histopathological parameters; waist circumference (WC); leptin; adiponectin; and leptin/adiponectin ratio (LAR) for all participants at baseline and every 3 years thereafter. We described the characteristics of participants at baseline and showed individual WC, LAR, and PVT characteristics. Potential parameters to predict PVT development within 9 years were determined. Results: PVT developed in eight (8.5%) patients, mainly in the portal trunk. Univariate analysis showed three PVT-associated factors: diabetes mellitus (P = 0.013), WC (P < 0.001), and LAR (P = 0.002). After adjusting multiple confounding variables, the multivariate model showed that the only significant variables were WC and LAR. By applying the receiver operating characteristic curve, WC had 98.8% specificity, 87.5% sensitivity, and 0.894 area under the curve (AUC) for prediction of PVT (P < 0.001) at cutoff values of > 105 cm. In comparison, LAR had 60.5% specificity, 87.5% sensitivity, and 0.805 AUC for PVT prediction (P < 0.001) at cutoff values of >7.5. Conclusions: This study suggests that increased central obesity and LAR were independently associated with PVT development in non-cirrhotic NAFLD patients, and they should be considered risk factors that may participate in PVT multifactorial pathogenesis.

Next-generation sequencing in the diagnosis of non-cirrhotic splanchnic vein thrombosis

BACKGROUND & AIMS

Myeloproliferative neoplasms (MPNs) are the most frequent cause of non-tumoural non-cirrhotic splanchnic vein thrombosis (NC-SVT). Diagnosis of MPN is based on blood cell count alterations, bone marrow histology, and detection of specific gene mutations. Next-generation sequencing (NGS) allows the simultaneous evaluation of multiple genes implicated in myeloid clonal pathology. The aim of this study was to evaluate the potential role of NGS in elucidating the aetiology of NC-SVT.

METHODS

DNA samples from 80 patients (75 with idiopathic or exclusively local factor [Idiop/loc-NC-SVT] and 5 with MPN and NC-SVT [SVT-MPN] negative for Janus kinase 2 gene [JAK2] [V617F and exon 12], calreticulin gene [CALR], and thrombopoietin gene [MPL] mutations by classic techniques) were analysed by NGS. Mutations involved in myeloid disorders different from JAK2, CALR, and MPL genes were categorised as high-molecular-risk (HMR) variants or variants of unknown significance.

RESULTS

In 2/5 triple-negative SVT-MPN cases (40%), a mutation in exon 12 of JAK2 was identified. JAK2-exon 12 mutation was also identified in 1/75 patients with Idiop/loc-NC-SVT. Moreover, 28/74 (37.8%) of the remaining Idiop/loc-NC-SVT had at least 1 HMR variant. Sixty-two patients with Idiop/loc-NC-SVT were not receiving long-term anticoagulation and 5 of them (8.1%) had recurrent NC-SVT. This cumulative incidence was significantly higher in patients with HMR variants than in those without.

CONCLUSIONS

NGS identified JAK2-exon12 mutations not previously detected by conventional techniques. In addition, NGS detected HMR variants in approximately one-third of patients with Idiop/loc-NC-SVT. These patients seem to have a higher risk of splanchnic rethrombosis. NGS might be a useful diagnostic tool in NC-SVT.

LAY SUMMARY

Next-generation sequencing (NGS) performs massive sequencing of DNA allowing the simultaneous evaluation of multiple genes even at very low mutational levels. Application of this technique in a cohort of patients with non-cirrhotic non-tumoral portal vein thrombosis (NC-SVT) and a negative study for thrombophilic disorders was able to identify patients with a mutation in exon 12 not previously detected by conventional techniques. Moreover, NGS detected High Molecular Risk (HMR)-variants (Mutations involved in myeloid disorders different from JAK2, CALR and MPL genes) in approximately one third of patients. These patients appear to be at increased risk of rethrombosis. All these findings supports NGS as a potential useful tool in the management of NC-SVT.

Budd-Chiari Syndrome: An Uncommon Cause of Chronic Liver Disease that Cannot Be Missed

Budd-Chiari syndrome (BCS), or hepatic venous outflow obstruction, is a rare cause of liver disease that should not be missed. Variable clinical presentation among patients with BCS necessitates a high index of suspicion to avoid missing this life-threatening diagnosis. BCS is characterized as primary or secondary, depending on etiology of venous obstruction. Most patients with primary BCS have several contributing risk factors leading to a prothrombotic state. A multidisciplinary stepwise approach is integral in treating BCS. Lifelong anticoagulation is recommended. Long-term monitoring of patients for development of cirrhosis, complications of portal hypertension, hepatocellular carcinoma, and progression of underlying diseases is important.

Prevalence of prothrombotic factors in patients with Budd-Chiari syndrome or non-cirrhotic nonmalignant portal vein thrombosis: A hospital-based observational study

BACKGROUND AND AIM

Comprehensive investigations on the prothrombotic factors of splanchnic vein thrombosis (SVT), including Budd-Chiari syndrome (BCS) and non-cirrhotic nonmalignant portal vein thrombosis (PVT), in Eastern patients are scarce.

METHODS

Between March 2012 and July 2017, 812 consecutive patients, including 418 BCS and 394 non-cirrhotic nonmalignant PVT patients, were admitted to Xijing Hospital (a Chinese tertiary academic hospital) and screened for prothrombotic factors. Odds ratios (ORs), 95% confidence intervals (CIs), and P-trends were calculated by using conditional logistic regression.

RESULTS

The prevalence of myeloproliferative neoplasms (MPNs) was only 6.3% among BCS patients but 28.3% among PVT patients. Notably, the presence of MPNs was associated with a higher risk of hepatic vein-type BCS (OR 9.9, 95% CI 3.6-26.7, P-trend < 0.001) and extensive thrombosis in PVT (OR 4.1, 95% CI 1.9-8.9, P-trend < 0.001). Calreticulin mutations existed in 2.7% of SVT patients. Furthermore, the prevalence of antiphospholipid antibody syndrome and protein C, protein S, or antithrombin deficiency in BCS patients was 7.3% and 22.5%, respectively, similar to that in patients with PVT (7.4% and 25.7%). In addition, factor V Leiden mutation, prothrombin G20210A mutation, and paroxysmal nocturnal hemoglobinuria were identified in < 1% of both BCS and PVT patients.

CONCLUSION

There is a significant positive association between MPNs and hepatic vein-type BCS or non-cirrhotic nonmalignant PVT with extensive thrombosis. Additionally, calreticulin mutations should be tested in JAK2^V617F -negative SVT patients in China. However, screening for factor V Leiden mutation, prothrombin G20210A mutation, and paroxysmal nocturnal hemoglobinuria may be unnecessary.

Congenital antithrombin deficiency in patients with splanchnic vein thrombosis

BACKGROUND AND AIMS

Splanchnic vein thromboses (SVT) are a rare condition that can be life-threatening. The most severe thrombophilia associated to SVT is antithrombin (AT) deficiency, usually caused by SERPINC1 mutations. Although transitory AT deficiencies and congenital disorders of the N-glycosylation pathways (CDG) have been recently reported as causes of AT deficiency, the current AT clinical screening still only includes anti-FXa activity. This study aims to (a) improve the detection of AT deficiency in SVT and (b) characterize the features of AT deficiency associated with SVT.

METHODS

The study was performed in 2 cohorts: (a) 89 SVT patients with different underlying etiologies but in whom AT deficiency had been ruled out by classical diagnostic methods; and (b) 271 unrelated patients with confirmed AT deficiency and venous thrombosis. AT was evaluated by functional (anti-FXa and anti-FIIa) and immunological methods (ELISA, crossed immunoelectrophoresis, western blot), and SERPINC1 sequencing was performed.

RESULTS

In 4/89 patients (4.5%) additional alterations in AT were found (two had SERPINC1 mutations, one had a specific variant causing transient AT deficiency and one patient had CDG). In 11 of the 271 patients (4.1%) with AT deficiency and thrombosis, thrombosis was located at the splanchnic venous territory.

CONCLUSIONS

Antithrombin deficiency may be underdiagnosed by current clinical screening techniques. Therefore, a comprehensive AT evaluation should be considered in cases of rethrombosis or doubtful interpretation of anti-FXa activity levels. SVT is a relatively common localization of the thrombotic event in patients with congenital AT deficiency.

Current knowledge in pathophysiology and management of Budd-Chiari syndrome and non-cirrhotic non-tumoral splanchnic vein thrombosis

Budd-Chiari syndrome and non-cirrhotic non-tumoral portal vein thrombosis are 2 rare disorders, with several similarities that are categorized under the term splanchnic vein thrombosis. Both disorders are frequently associated with an underlying prothrombotic disorder. They can cause severe portal hypertension and usually affect young patients, negatively influencing life expectancy when the diagnosis and treatment are not performed at an early stage. Yet, they have specific features that require individual consideration. The current review will focus on the available knowledge on pathophysiology, diagnosis and management of both entities.

Review article: a multidisciplinary approach to the diagnosis and management of Budd-Chiari syndrome

BACKGROUND

Budd-Chiari syndrome (BCS) is a rare but fatal disease caused by obstruction in the hepatic venous outflow tract.

AIM

To provide an update of the pathophysiology, aetiology, diagnosis, management and follow-up of BCS.

METHODS

Analysis of recent literature by using Medline, PubMed and EMBASE databases.

RESULTS

Primary BCS is usually caused by thrombosis and is further classified into "classical BCS" type where obstruction occurs within the hepatic vein and "hepatic vena cava BCS" which involves thrombosis of the intra/suprahepatic portion of the inferior vena cava (IVC). BCS patients often have a combination of prothrombotic risk factors. Aetiology and presentation differ between Western and certain Asian countries. Myeloproliferative neoplasms are present in 35%-50% of European patients and are usually associated with the JAK2-V617F mutation. Clinical presentation is diverse and BCS should be excluded in any patient with acute or chronic liver disease. Non-invasive imaging (Doppler ultrasound, computed tomography, or magnetic resonance imaging) usually provides the diagnosis. Liver biopsy should be obtained if small vessel BCS is suspected. Stepwise management strategy includes anticoagulation, treatment of identified prothrombotic risk factors, percutaneous revascularisation and transjugular intrahepatic portosystemic stent shunt to re-establish hepatic venous drainage, and liver transplantation in unresponsive patients. This strategy provides a 5-year survival rate of nearly 90%. Long-term outcome is influenced by any underlying haematological condition and development of hepatocellular carcinoma.

CONCLUSIONS

With the advent of newer treatment strategies and improved understanding of BCS, outcomes in this rare disease have improved over the last three decades. An underlying haematological disorder can be the major determinant of outcome.

Prevalence of CALR mutations in splanchnic vein thrombosis: A systematic review and meta-analysis

BACKGROUND

The prevalence of calreticulin (CALR) mutations in splanchnic vein thrombosis (SVT) varies among studies. The role of routine screening for CALR mutations in SVT patients remains a debate.

AIM

To synthesize the prevalence of CALR mutations according to the different types (i.e., Budd-Chiari syndrome [BCS] and portal vein thrombosis [PVT]) and characteristics (i.e., with and without myeloproliferative neoplasms [MPNs] and JAK2V617F mutation) of SVT patients.

METHODS

Eligible studies were searched by the PubMed and Embase databases. The study quality was assessed according to the STROBE checklist. The proportion of CALR mutations was pooled by using a random-effects model. The heterogeneity and publication bias were calculated.

RESULTS

Eleven papers were included. The study quality was moderate to high. The pooled proportion of CALR mutations was 1.21%, 1.41%, and 1.59% in SVT, BCS, and PVT patients, respectively; 1.52%, 1.03%, and 1.82% in these patients without JAK2V617F mutation, respectively; 3.71%, 2.79%, and 7.87% in these patients with MPN, respectively; and 15.16%, 17.22%, and 31.44% in these patients with MPN but without JAK2V617F mutation, respectively. Only the meta-analysis examining the prevalence of CLAR mutations in BCS patients with MPN but without the JAK2V617F mutation showed statistically significant heterogeneity. Statistically significant publication bias was seen only in the meta-analysis examining the prevalence of CALR mutations in SVT patients without the JAK2V617F mutation.

CONCLUSION

Screening for CALR mutations may have a role in SVT patients with a high probability of MPN in whom the JAK2V617F mutation has been excluded.

Current approaches to challenging scenarios in myeloproliferative neoplasms

INTRODUCTION

The Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) including polycythemia vera, essential thrombocythemia and primary myelofibrosis are clonal hematological malignancies that originate at the level of the hematopoietic stem cell, and are characterized by excessive proliferation of cells belonging to one or more of the myeloid lineages. Central to the pathogenesis of the MPNs is constitutive activation of the JAK/STAT signaling pathway due to a family of driver mutations affecting JAK2, CALR or MPL. These disorders share common clinical and laboratory features, a significant burden of systemic symptoms, increased risk of developing arterial and venous thrombotic events, and the potential to progress to myelofibrosis and acute leukemia. Areas covered: We identified four clinical situations which represent challenging management dilemmas for patients with MPNs. Our conclusions and recommendations are based on a literature search using MEDLINE and recent meeting abstracts using the keywords, focusing on publications directly addressing these scenarios and on recent contributions to the field. Expert commentary: Multi-center efforts to study large cohorts of MPN patients have led to more uniform and evidence-based approaches to key aspects in MPN management. However, treatment strategies to deal with specific clinical scenarios are lacking.

Selective testing for calreticulin gene mutations in patients with splanchnic vein thrombosis: A prospective cohort study

BACKGROUND AND AIMS

Myeloproliferative neoplasms (MPN) are the leading cause of splanchnic vein thrombosis (SVT). Janus kinase 2 gene (JAK2)^V617F mutations are found in 80 to 90% of patients with SVT and MPN. Mutations of the calreticulin (CALR) gene have also been reported. However, as their prevalence ranges from 0 to 2%, the utility of routine testing is questionable. This study aimed to identify a group of patients with SVT at high risk of harboring CALR mutations and thus requiring this genetic testing.

METHODS

CALR, JAK2^V617F and thrombopoietin receptor gene (MPL) mutations were analysed in a test cohort that included 312 patients with SVT. Criteria to identify patients at high risk of CALR mutations in this test cohort was used and evaluated in a validation cohort that included 209 patients with SVT.

RESULTS

In the test cohort, 59 patients had JAK2^V617F, five had CALR and none had MPL mutations. Patients with CALR mutations had higher spleen height and platelet count than patients without these mutations. All patients with CALR mutations had a spleen height ⩾16cm and platelet count >200×10⁹/L. These criteria had a positive predictive value of 56% (5/9) and a negative predictive value of 100% (0/233) for the identification of CALR mutations. In the validation cohort, these criteria had a positive predictive value of 33% (2/6) and a negative predictive value of 99% (1/96).

CONCLUSION

CALR mutations should be tested in patients with SVT, a spleen height ⩾16cm, platelet count >200×10⁹/L, and no JAK2^V617F. This strategy avoids 96% of unnecessary CALR mutations testing. Lay summary: Mutations of the CALR gene are detected in 0 to 2% of patients with SVT, thus the utility of systematic CALR mutation testing to diagnose MPN is questionable. This study demonstrates that CALR mutations testing can be restricted to patients with SVT, a spleen height ⩾16cm, a platelet count >200×10⁹/L, and no JAK2^V617F. This strategy avoids 96% of unnecessary CALR mutations testing.

Budd-Chiari syndrome/hepatic venous outflow tract obstruction

BACKGROUND

Budd-Chiari syndrome (BCS) is a rare disease characterized by hepatic venous outflow tract obstruction (HVOTO).

METHODS

Recent literature has been analyzed for this narrative review.

RESULTS

Primary BCS/HVOTO is a result of thrombosis. The same patient often has multiple risk factors for venous thrombosis and most have at least one. Presentation and etiology may differ between Western and certain Eastern countries. Myeloproliferative neoplasms are present in 40% of patients and are usually associated with the V617F-JAK2 mutation in myeloid cells, in particular peripheral blood granulocytes. Presentation and symptoms vary, thus this diagnosis must be considered in any patient with acute or chronic liver disease. Doppler ultrasound, computed tomography, or magnetic resonance imaging of the hepatic veins and inferior vena cava usually successfully provide noninvasive identification of the obstruction or its consequences in the collaterals of hepatic veins or the inferior vena cava. The reported life expectancy in these patients is 3 years after the first symptoms. The therapeutic strategy includes first, anticoagulation, correction of risk factors, diuretics, and prophylaxis for portal hypertension, then angioplasty for short-length venous stenosis followed by transjugular intrahepatic portosystemic shunt (TIPS) and finally liver transplantation. The progression of treatment is based on the response to therapy at each step. This strategy results in a 5-year survival rate of nearly 85%. The medium-term prognosis depends upon the severity of liver disease, and the long-term outcome can be jeopardized by transformation of underlying conditions and hepatocellular carcinoma.

CONCLUSION

BCS/HVOTO hepatic manifestations of BCS/HVOTO can be controlled in most patients with medical or radiological interventions. Underlying disease has become the major determinant of patient outcome.

Splanchnic vein thrombosis in myeloproliferative neoplasms: pathophysiology and molecular mechanisms of disease

Myeloproliferative neoplasms (MPNs) are the most common underlying prothrombotic disorder found in patients with splanchnic vein thrombosis (SVT). Clinical risk factors for MPN-associated SVTs include younger age, female sex, concomitant hypercoagulable disorders, and the JAK2 V617F mutation. These risk factors are distinct from those associated with arterial or deep venous thrombosis (DVT) in MPN patients, suggesting disparate disease mechanisms. The pathophysiology of SVT is thought to derive from local interactions between activated blood cells and the unique splanchnic endothelial environment. Other mutations commonly found in MPNs, including CALR and MPL, are rare in MPN-associated SVT. The purpose of this article is to review the clinical and molecular risk factors for MPN-associated SVT, with particular focus on the possible mechanisms of SVT formation in MPN patients.

Review article: the aetiology of primary Budd-Chiari syndrome - differences between the West and China

BACKGROUND

China may have the largest number of Budd-Chiari syndrome (BCS) cases in the world (at least 1914 original papers were published, and at least 20 191 BCS patients were reported). Considering the discrepancy in the clinical profiles and preferred treatment selection of primary BCS between the West and China, understanding its aetiology in these two different regions is very important.

AIM

To review the data from large cohort studies and meta-analyses to illustrate the epidemiology of risk factors for BCS in the West and China.

METHODS

Relevant papers were identified by major English- and Chinese-language databases, conference abstracts, and by manual search.

RESULTS

Risk factors reviewed include myeloproliferative neoplasms (MPNs) and their related gene mutations, anti-phospholipid syndrome, paroxysmal nocturnal haemoglobinuria (PNH), hyperhomocysteinaemia and 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T mutation, factor V Leiden (FVL) and prothrombin G20210A mutations, inherited anti-thrombin, protein C and protein S deficiencies, pregnancy and puerperium, poverty, and family history.

CONCLUSIONS

We examined the differences in the aetiological distribution of BCS between the West and China. Several recommendations should be considered in Chinese BCS patients: (i) screening for hyperhomocysteinaemia and MTHFR mutation should be regularly performed; (ii) screening for MPNs, PNH, and anti-phospholipid syndrome should be selectively performed; (iii) inherited anti-thrombin, protein C, and protein S deficiencies should be actively explored; (iv) screening for FVL and prothrombin G20210A mutations may be unnecessary; and (v) the clinical significance of pregnancy and puerperium, poverty with bacterial infections and unsanitary environments, and family history as possible risk factors should never be neglected.

Genetic Risk Factors of Venous Thromboembolism in the East Algerian Population

Many genetic risk factors have been identified for causing venous thromboembolism (VTE). Most of them affect the function of natural anticoagulant pathways, particularly the protein C system, although recent studies suggest a role of components of the hematopoietic pathway in the etiology of venous thrombosis. In this case–control study, we aimed to determine the frequency of prothrombin G20210A and factor V Leiden (FVL) G1691A polymorphisms and protein C, protein S, and antithrombin III deficiencies in the East Algerian population and to investigate whether these genetic factors are associated with VTE. On the other hand, our study tends to evaluate the status of JAK2V617F and calreticulin (CALR) mutations among these cases. The participants consisted of 121 cases with VTE and 146 healthy controls. Polymorphisms of FVL G1691A and prothrombin G20210A were genotyped by polymerase chain reaction (PCR) restriction fragment length polymorphism. JAK2-V617F and calreticulin mutations were analyzed by quantitative PCR and PCR followed by capillary electrophoresis sequencing, respectively. Protein C, protein S, and antithrombin levels were determined and then hereditary deficiencies were identified. Of all cases and controls, none was a carrier of the antithrombin III deficiency, prothrombin gene G20210A, and CALR mutations. Only 1 case reported having a positive JAK2 mutation (mutant allele burden was 15%). The FVL mutation (GA/AA) was found in 14 (11.6%) cases and 2 (1.4%) controls and it was significantly different between both the groups ( P = .001). Deficiencies of protein S and protein C were detected in 17 (18.8%) cases. The univariate analysis resulted in a significant impact of FVL (odds ratio [OR] = 9.4, 95% confidence interval [CI] = 2.1-42.3; P = .003) and of protein S deficiency (OR = 16.9, 95% CI =2.1-132.8, P = .007) on the VTE status. Both factors stayed significant after adjustment for sex and age. The OR of the protein C deficiency was slightly elevated (OR = 6.4, 95% CI = 0.7-55.5), but it did not reach the level of statistical significance ( P = .091), and it was therefore not considered as a risk factor. In conclusion, coagulant factor V gene G1691A mutation and protein S deficiency constitute important genetic risk factors in patients with VTE in Eastern Algeria. The somatic mutation of JAK2 V617F and CALR mutations are less frequent causes of VTE, thus routine testing for these mutations is not recommended.