Anticoagulant therapy for splanchnic vein thrombosis: ISTH SSC Subcommittee Control of Anticoagulation

Portal vein thrombosis: diagnosis, management, and endpoints for future clinical studies

Portal vein thrombosis (PVT) refers to the development of a non-malignant obstruction of the portal vein, its branches, its radicles, or a combination. This Review first provides a comprehensive overview of all aspects of PVT, namely the specifics of the portal venous system, the risk factors for PVT, the pathophysiology of portal hypertension in PVT, the interest in non-invasive tests, as well as therapeutic approaches including the effect of treating risk factors for PVT or cause of cirrhosis, anticoagulation, portal vein recanalisation by interventional radiology, and prevention and management of variceal bleeding in patients with PVT. Specific issues are also addressed including portal cholangiopathy, mesenteric ischaemia and intestinal necrosis, quality of life, fertility, contraception and pregnancy, and PVT in children. This Review will then present endpoints for future clinical studies in PVT, both in patients with and without cirrhosis, agreed by a large panel of experts through a Delphi consensus process. These endpoints include classification of portal vein thrombus extension, classification of PVT evolution, timing of assessment of PVT, and global endpoints for studies on PVT including clinical outcomes. These endpoints will help homogenise studies on PVT and thus facilitate reporting, comparison between studies, and validation of future studies and trials on PVT.

Efficacy and safety of rivaroxaban versus warfarin in the management of unusual site deep vein thrombosis: a retrospective cohort study

Background

Unusual site deep vein thrombosis (DVT) was defined as venous thromboembolism (VTE) occurring outside the conventional deep veins of the lower extremity or pulmonary arteries. However, the optimal anticoagulation therapy for unusual site DVT remained unclear. This study aims to evaluate the efficacy and safety of rivaroxaban in unusual site DVT.

Methods

This retrospective cohort study enrolled consecutive patients at Nanjing Drum Tower Hospital between January 2011 and December 2021 who were diagnosed with unusual site DVT. Patients were divided into two groups based on their ultimate medication choice: the warfarin group and the rivaroxaban group. The demographic characteristics were recorded for all enrolled patients. Clinical outcomes included recurrent VTE, bleeding complications and major bleeding.

Results

A total of 1,088 patients were divided into warfarin (n = 514) and rivaroxaban (n = 574) groups. After the stabilized inverse probability of treatment weighting, Hazard Ratios for warfarin vs. rivaroxaban of recurrent VTE, bleeding complications and major bleeding were 0.52(95% CI: 0.25-1.08), 0.30(95% CI: 0.14-0.60), and 0.33 (95% CI, 0.13-0.74), respectively. Risk of clinical outcomes in specified subgroups for age, gender, renal function, thrombosis sites and diagnosis were assessed. The interaction of gender and treatment on major bleeding was significant (P for interaction = 0.062). Otherwise, there was no significant interaction between the other subgroups and the treatment group in terms of clinical outcomes.

Conclusion

Compared with warfarin, rivaroxaban exhibited comparable efficacy for the anticoagulant treatment of unusual site DVT, associated with a lower risk of bleeding complications and major bleeding.

Comparing clinical outcomes of vitamin K antagonists vs non-vitamin K antagonists in anticoagulant therapy for mesenteric venous thrombosis

OBJECTIVE

Non-vitamin K antagonist oral anticoagulants have shown similar efficacy and lower bleeding rates than vitamin K antagonists for venous thromboembolism. However, this has not been proven in mesenteric vein thrombosis. This study aimed to compare the clinical outcomes of vitamin K antagonists and non-vitamin K antagonist oral anticoagulants.

METHODS

Between January 2014 and July 2022, mesenteric vein thrombosis was diagnosed on computed tomography in 225 patients in a tertiary hospital. Among them, a total of 44 patients who underwent long-term anticoagulation therapy over 3 months were enrolled in this study. Patients were divided into two groups based on the anticoagulant used: vitamin K antagonists (Group 1, n = 21) and non-vitamin K antagonist oral anticoagulants (Group 2, n = 23). The efficacy outcomes were symptom recurrence and thrombus resolution on follow-up computed tomography, and the safety outcome was bleeding complications.

RESULTS

The median age of the patients was 56 years (range, 46-68 years), and 52% were men. The most common risk factors were unprovoked intra-abdominal infections (30%). The median duration of anticoagulation therapy was 13 months (20 months in Group 1 vs 6 months in Group 2; P = .076). Of the 44 patients, 17 (39%) received the standard treatment. The median follow-up period was longer in Group 1 than in Group 2 (57 vs 28 months; P = .048). No recurrence of mesenteric vein thrombosis-related symptoms were observed in either group. The median duration of follow-up computed tomography was 31 months (42 months in Group 1 vs 18 months in Group 2; P = .064). Computed tomography revealed complete thrombus resolution, partial resolution, and no changes in 71%, 19%, and 10%, respectively (P = .075). Regarding bleeding complications, varix bleeding and melena developed in two patients in Group 2, and anticoagulation treatment thereafter ceased.

CONCLUSIONS

Despite the short follow-up duration in the non-vitamin K antagonist oral anticoagulants group, there was no clinically significant difference in the thrombus resolution rate or bleeding complications when compared with the vitamin K antagonists group. Although research on the long-term effects of non-vitamin K antagonist oral anticoagulants in patients is limited, non-vitamin K antagonist oral anticoagulants can be considered an alternative to conventional treatments.

Natural history of cancer-associated splanchnic vein thrombosis

BACKGROUND

There is uncertainty in the management of cancer-associated isolated splanchnic vein thrombosis (SpVT).

OBJECTIVES

To describe the natural history of SpVT by cancer type and thrombus composition and to review anticoagulation (AC) practices and associated rates of usual-site venous thromboembolism (VTE), major and clinically relevant nonmajor bleeding (MB/CRNMB), recanalization/progression, and mortality.

METHODS

We performed a retrospective cohort study in patients with SpVT at 2 cancer care centers in Houston, Texas. We estimated the incidence of usual-site VTE and MB/CRNMB at 6 months using competing risk methods and examined venous patency in a subset of patients with repeat imaging. We assessed associations with mortality using Cox regression.

RESULTS

Among 15 342 patients with an incident cancer diagnosis from 2011 to 2020, we identified 298 with isolated SpVT. Patients with hepatocellular carcinoma (HCC) and SpVT (n = 146) had the highest disease prevalence (20%), lowest rate of AC treatment (2%), and similar rate of usual-site VTE (4.2%) vs those without SpVT (5.2%) at 6 months, though tumor thrombus vs bland was associated with worse overall survival. In patients with non-HCC bland SpVT (n = 114), AC (n = 37) was more common in those with non-upper gastrointestinal cancers and fewer comorbidities. AC was associated with more recanalization (44% vs 15%, P = .041) but no differences in usual-site VTE, MB/CRNMB, or mortality at 6 months.

CONCLUSION

Cancer-associated isolated SpVT is a common but heterogeneous thrombotic disease that is treated differently from usual-site VTE. Tumor thrombus is a negative prognostic factor. Initiation of AC in bland thrombi requires judicious consideration of thrombotic and bleeding risk.

Direct oral anticoagulants for treatment of venous thrombosis: illustrated review of appropriate use

Direct oral anticoagulants (DOACs) have become the preferred option for treatment of venous thromboembolism due to their favorable profile compared with other agents such as vitamin K antagonists or low-molecular-weight heparin. However, findings from randomized controlled trials suggest efficacy and/or safety concerns with DOAC use in some clinical contexts. This illustrated review will summarize indications where DOACs have proven efficacy and safety, situations where they fall short, and situations where uncertainty remains compared with other treatments for venous thromboembolism.

Diagnosis and Therapy of Visceral Vein Thrombosis: An Update Based on the Revised AWMF S2k Guideline

Splanchnic or visceral vein thromboses (VVTs) are atypical thrombotic entities and include thrombosis of the portal vein, hepatic veins (Budd-Chiari syndrome), mesenteric veins, and splenic vein. All VVTs have in common high 30-day mortality up to 20% and it seems to be difficult to diagnose VVT early because of their rarity and their wide spectrum of unspecific symptoms. VVTs are often associated with myeloproliferative neoplasia, thrombophilia, and liver cirrhosis. VVT is primarily diagnosed by sonography and/or computed tomography. In contrast to venous thromboembolism, D-dimer testing is neither established nor helpful. Anticoagulation is the first-line therapy in patients with stable circulation and no evidence of organ complications. Anticoagulation improves significantly recanalization rates and stops the progress of thrombosis. Low-molecular-weight heparin, vitamin K antagonists, as well as direct-acting oral anticoagulants are possible anticoagulants, but it is noteworthy to be aware that all recommendations supporting the off-label use of anticoagulants are based on poor evidence and consist predominantly of case series, observational studies, or studies with small case numbers. When choosing a suitable anticoagulation, the individual risk of bleeding and thrombosis must be weighted very carefully. In cases of bleeding, bowel infarction, or other complications, the optimal therapy should be determined on a case-by-case basis by an experienced multidisciplinary team involving a surgeon. Besides anticoagulation, there are therapeutic options including thrombectomy, balloon angioplasty, stenting, transjugular placement of an intrahepatic portosystemic shunt, liver transplantation, and ischemic bowel resection. This article gives an overview of current diagnostic and therapeutic strategies.

Antithrombotic Therapy for VTE Disease: Compendium and Review of CHEST Guidelines 2012-2021

The CHEST Antithrombotic Therapy for Venous Thromboembolism Disease evidence-based guidelines are now updated in a more frequent, focused manner. Guidance statements from the most recent full guidelines and two subsequent updates have not been gathered into a single source. An international panel of experts with experience in prior antithrombotic therapy guideline development reviewed the 2012 CHEST antithrombotic therapy guidelines and its two subsequent updates. All guideline statements and their associated patient, intervention, comparator, and outcome questions were assembled. A modified Delphi process was used to select statements considered relevant to current clinical care. The panel further endorsed minor phrasing changes to match the standard language for guidance statements using the modified Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) format endorsed by the CHEST Guidelines Oversight Committee. The panel appended comments after statements deemed as relevant, including suggesting that statements be updated in future guidelines because of interval evidence. We include 58 guidance statements from prior versions of the antithrombotic therapy guidelines, with updated phrasing as needed to adhere to contemporary nomenclature. Statements were classified as strong or weak recommendations based on high-certainty, moderate-certainty, and low-certainty evidence using GRADE methodology. The panel suggested that five statements are no longer relevant to current practice. As CHEST continues to update guidance statements relevant to antithrombotic therapy for VTE disease, this article serves as a unified collection of currently relevant statements from the preceding three guidelines. Suggestions have been made to update specific statements in future publications.

Cancer-associated splanchnic vein thrombosis: Clinical implications and management considerations

Splanchnic vein thrombosis (SVT), a thrombosis which involves the portal, mesenteric, and splenic veins, and the Budd-Chiari syndrome, represents an uncommon type of venous thromboembolism (VTE). Like with deep vein thrombosis of the lower extremities and pulmonary embolism, ample evidence suggests a significant association between SVT and cancer, particularly intra-abdominal solid malignancies (e.g. hepatobiliary and pancreatic cancers) and myeloproliferative neoplasms (MPN). Clinical symptoms of SVT in cancer patients can be ambiguous, and frequently attributed to the primary cancer itself. Alternatively, SVT may be asymptomatic and detected incidentally during cancer staging or follow-up evaluations. SVT can also precede the diagnosis of cancer and has been associated with poorer outcomes in patients with liver or pancreatic cancers. Therefore, an unprovoked SVT warrants a thorough evaluation for an underlying malignancy or MPN. Cancer-associated SVT carries a high risk of VTE extension, recurrence and bleeding. Extended anticoagulant treatment is often required in the absence of a high bleeding risk. Guidelines suggest treatment with either low molecular weight heparin (LMWH) or direct oral anticoagulants (DOACs), although available data on the safety and effectiveness of DOACs in these patients is limited. This comprehensive review outlines the epidemiology, pathogenesis, risk factors, and diagnosis of cancer-associated SVT and underscores the importance of comprehensive patient evaluation and evidence-based management.

Efficacy and safety of direct oral anticoagulants in splanchnic vein thrombosis: a pooled analysis of literature studies

BACKGROUND

Limited evidence is available on management of splanchnic vein thrombosis (SVT).

OBJECTIVES

This study aimed to evaluate safety and efficacy of direct oral anticoagulants (DOACs) for SVT treatment.

METHODS

Studies were systematically searched in the PubMed, Web of Science, and Scopus databases according to PRISMA guidelines. We assessed any recanalization, full recanalization, recurrence, mortality, and major bleeding as outcomes of interest. Results were reported as weighted mean prevalence (WMP) with 95% CI. Subgroup analyses and meta-regressions have been performed to address heterogeneity and adjust for potential confounders.

RESULTS

We included a total of 16 studies (17 datasets) on 648 patients with SVT treated with DOACs. We found any recanalization in 60.3% (95% CI: 41.8%-76.3%; I2 = 84.9%; P < .001) and full recanalization in 51.7% (95% CI: 36.0%-67.0%; I2 = 87.4%; P < .001). Recurrent venous thromboembolism occurred in 2.8% (95% CI: 1.4%-5.9%; I2 = 0%; P = .787) and death in 3.4% (95% CI: 1.6%-7.3%; I2 = 13.2%; P = .318) of patients. Major bleeding was reported by 5.8% (95% CI: 3.7%-8.9%; I2 = 29.2%; P = .125) of patients. Results were consistent when separately analyzing prospective studies, retrospective studies, studies on cirrhotic patients, and studies enrolling patients with portal vein thrombosis. Meta-regression analyses showed that an increasing age and cancer impacted the rate of recanalization. Cirrhosis was associated with a higher rate of major bleeding and mortality.

CONCLUSION

The results of the present study, mostly based on observational studies, suggest good safety and efficacy profiles of DOACs in patients with SVT. Randomized studies are needed to corroborate our findings.

When Direct Oral Anticoagulants Should Not Be Standard Treatment: JACC State-of-the-Art Review

For most patients, direct oral anticoagulants (DOACs) are preferred over vitamin K antagonists for stroke prevention in atrial fibrillation and for venous thromboembolism treatment. However, randomized controlled trials suggest that DOACs may not be as efficacious or as safe as the current standard of care in conditions such as mechanical heart valves, thrombotic antiphospholipid syndrome, and atrial fibrillation associated with rheumatic heart disease. DOACs do not provide a net benefit in conditions such as embolic stroke of undetermined source. Their efficacy is uncertain for conditions such as left ventricular thrombus, catheter-associated deep vein thrombosis, cerebral venous sinus thrombosis, and for patients with atrial fibrillation or venous thrombosis who have end-stage renal disease. This paper provides an evidence-based review of randomized controlled trials on DOACs, detailing when they have demonstrated efficacy and safety, when DOACs should not be the standard of care, where their safety and efficacy are uncertain, and areas requiring further research.

Therapeutic anticoagulation in patients with acute pancreatitis and splanchnic vein thrombosis: a best evidence topic

A best evidence topic in general surgery was written according to a structured protocol. The clinical question addressed was: in adult patients with splanchnic vein thrombosis in acute pancreatitis, would administration of therapeutic anticoagulation be advisable considering the rates of vessel recanalization and bleeding complications? Four hundred twenty-four papers were found on Ovid Embase and Medline whilst 222 were found on PubMed using the reported literature search. From these, five articles represented the best evidence to the clinical question. The authors, publication dates, countries, patient groups, study outcomes, and results of these papers were tabulated. There were three systematic reviews with meta-analyses, one systematic review without meta-analysis and one randomized, retrospective study. The authors conclude that among patients with splanchnic vein thrombosis in the context of acute pancreatitis, therapeutic anticoagulation improved the rates of recanalization without increasing the risk of bleeding complications. However, there remains a need for randomized studies to address this clinical dilemma to further increase the quality of available evidence.

A narrative review of acute pancreatitis-induced splanchnic vein thrombosis: from pathogenesis to clinical management

Acute pancreatitis-induced splanchnic vein thrombosis (APISVT) is an important sequela complication of acute pancreatitis, which may cause poor prognosis, such as severe gastrointestinal hemorrhage, bowel ischemic necrosis and liver failure. However, its mechanism remains uncertain, and there is not a general consensus on the management. In this study, we reviewed the latest academic publications in APISVT, and discussed its pathogenesis, clinical presentation, adverse outcome and treatment, especially focused on the role of anticoagulant therapy. It was indicated that anticoagulation therapy can significantly elevate thrombus recanalization and reduce the incidence of complications and mortality with no increase of bleeding. Actually, as most of these studies were retrospective analyses and prospective studies included small samples, the conclusion remains controversial. Thus, well-designed randomized controlled trials are urged to verify the effectiveness and safety of anticoagulation therapy for APISVT.

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.

How to manage splanchnic vein thrombosis in patients with liver disease

Liver cirrhosis and splanchnic vein thrombosis (SVT) are strictly correlated. Portal vein thrombosis, the most common location of SVT, is frequently diagnosed in liver cirrhosis (pooled incidence 4.6 per 100 patient-years), and liver cirrhosis is a common risk factor for SVT (reported in 24%-28% of SVT patients). In cirrhosis-associated SVT, anticoagulant treatment reduces mortality rates, thrombosis extension, and major bleeding, and increases the rates of recanalization, compared to no treatment. Achieving vessel recanalization improves the prognosis of cirrhotic patients by reducing liver-related complications (such as variceal bleeding, ascites, hepatic encephalopathy). Anticoagulation should be therefore routinely prescribed to cirrhotic patients with acute SVT unless contraindicated by active bleeding associated with hemodynamic impairment or by excessively high bleeding risk. Of note, early treatment is associated with higher probability of achieving vessel recanalization. The standard treatment consists of low-molecular-weight heparin, followed by oral anticoagulants (eg, vitamin K antagonists or direct oral anticoagulants), if not contraindicated by severe liver dysfunction. Cirrhotic patients with SVT should be treated long-term (especially if candidate for liver transplantation) since liver cirrhosis is a persistent risk factor for recurrent thrombosis. In this review, we discuss the management of SVT in patients with liver cirrhosis, with a focus on the anticoagulant treatment in terms of indications, timing, drugs, duration, and particular scenarios, such as gastroesophageal varices and thrombocytopenia.

American Society of Hematology 2023 guidelines for management of venous thromboembolism: thrombophilia testing

Hereditary and acquired thrombophilia are risk factors for venous thromboembolism (VTE). Whether testing helps guide management decisions is controversial. These evidence-based guidelines from the American Society of Hematology (ASH) intend to support decision making about thrombophilia testing. ASH formed a multidisciplinary guideline panel covering clinical and methodological expertise and minimizing bias from conflicts of interest. The McMaster University GRADE Centre provided logistical support, performed systematic reviews, and created evidence profiles and evidence-to-decision tables. The Grading of Recommendations Assessment, Development, and Evaluation approach (GRADE) was used. Recommendations were subject to public comment. The panel agreed on 23 recommendations regarding thrombophilia testing and associated management. Nearly all recommendations are based on very low certainty in the evidence due to modeling assumptions. The panel issued a strong recommendation against testing the general population before starting combined oral contraceptives (COCs) and conditional recommendations for thrombophilia testing in the following scenarios: (a) patients with VTE associated with nonsurgical major transient or hormonal risk factors; (b) patients with cerebral or splanchnic venous thrombosis, in settings where anticoagulation would otherwise be discontinued; (c) individuals with a family history of antithrombin, protein C, or protein S deficiency when considering thromboprophylaxis for minor provoking risk factors and for guidance to avoid COCs/hormone replacement therapy; (d) pregnant women with a family history of high-risk thrombophilia types; and (e) patients with cancer at low or intermediate risk of thrombosis and with a family history of VTE. For all other questions, the panel provided conditional recommendations against testing for thrombophilia.

Cancer-Associated Abdominal Vein Thrombosis

Cancer is associated with an increased risk of developing venous thromboembolism, due to its direct influence on the three pillars of Virchow's triad (e.g., compression on the blood vessels by the tumour, blood vessels invasion, and cytokine release), together with the effect of exogenous factors (such as chemotherapy, radiotherapy, surgery). In cancer patients, the risk of thrombosis at unusual sites, such as splanchnic, ovarian and renal vein thrombosis, is also increased. Abdominal vein thromboses are frequently incidental findings on abdominal imaging performed as part of the diagnostic/staging workup or the follow-up care of malignancies. There is little evidence on the management of unusual site venous thromboembolism in cancer patients since there are only a few specific recommendations; thus, the management follows the general principles of the treatment of cancer-associated deep vein thrombosis and pulmonary embolism. This narrative review summarises the latest evidence on cancer-associated abdominal vein thrombosis, i.e., thrombosis of the splanchnic, ovarian and renal veins.

Risk of Bleeding in Liver Cirrhosis Receiving Direct Oral Anticoagulants: A Systematic Review and Meta-analysis

BACKGROUND

 Direct oral anticoagulants (DOACs) are effective for the management of thromboembolic disorders. However, bleeding remains a major concern in cirrhotic patients receiving DOACs.

METHODS

 PubMed, EMBASE, and Cochrane Library databases were searched. The incidence of bleeding episodes in cirrhotic patients receiving DOACs was pooled. Odds ratios (ORs) were calculated to compare the incidence of bleeding episodes in cirrhotic patients who received DOACs versus those who received conventional anticoagulants and did not receive anticoagulants.

RESULTS

 Twenty-nine studies were included. All bleeding, major bleeding, fatal bleeding, gastrointestinal bleeding, and intracranial hemorrhage episodes were observed in 310/2,469, 100/1,388, 2/611, 166/1,886, and 5/1,147 cirrhotic patients receiving DOACs, respectively. Their pooled incidences were 13, 6, 0, 8, and 0%, respectively. They became higher in subgroup analyses of studies with advanced age, a longer treatment duration, and Child-Turcotte-Pugh class C. Compared with conventional anticoagulants, DOACs were associated with lower incidences of all bleeding (OR = 0.71, 95% confidence interval [CI] = 0.52-0.98) and major bleeding (OR = 0.55, 95% CI = 0.37-0.83) in cirrhotic patients, but not those of fatal bleeding (OR = 0.21, 95% CI = 0.04-1.28), gastrointestinal bleeding (OR = 0.78, 95% CI = 0.52-1.17), or intracranial hemorrhage (OR = 0.36, 95% CI = 0.12-1.12). The incidences of all bleeding (OR = 1.04, 95% CI = 0.22-4.79) and major bleeding (OR = 0.96, 95% CI = 0.26-3.61) did not significantly differ between cirrhotic patients with portal vein thrombosis (PVT) who received DOACs and those who did not receive anticoagulants.

CONCLUSION

 DOACs carry a low risk of bleeding in liver cirrhosis. Age, treatment duration, and Child-Turcotte-Pugh class may be associated with bleeding in cirrhotic patients receiving DOACs. The risk of bleeding is not increased by DOACs in cirrhotic patients with PVT.

Cancer-associated splanchnic vein thrombosis: Clinical features upon diagnosis and short-term outcomes

INTRODUCTION

The incidence of splanchnic vein thrombosis (SVT) in cancer patients has increased in recent years and its real clinical significance and management can be challenging. This study aimed to describe the clinical presentation and short-term outcomes of patients with cancer-associated SVT.

MATERIAL AND METHODS

This was a retrospective observational study of consecutive patients with cancer-associated SVT diagnosed during the period 2015-2020. The primary objective was to describe the clinical presentation of SVT. Patients were clinically classified into two groups based on the presence of symptoms on SVT diagnosis. The main outcomes were overall and SVT-related mortality, major and non-major bleeding rates, and the thrombosis recurrence rate in the first 30 days of follow-up.

RESULTS

This study enrolled 203 patients. Intra-abdominal tumors (76 %) and metastatic disease (68 %) predominated. A total of 79 (39 %) patients without symptoms were diagnosed with SVT during a scheduled radiological test and were classified as "asymptomatic", while 124 (61 %) patients presented some potential SVT symptoms and were considered as "symptomatic". Although the 30-day outcomes showed no significant differences between the two groups, mortality in the asymptomatic group was slightly lower compared to the symptomatic group (3 % vs. 10 %, p = 0.085).

CONCLUSIONS

Almost 40 % of cases of cancer-associated SVT are asymptomatic. There were no significant differences in short-term outcomes between the symptomatic and asymptomatic patients. More studies are required to better define long-term management and outcomes in these patients.

Splanchnic vein thrombosis in acute pancreatitis: a review of treatment indications, methods, and outcomes in a single institution

BACKGROUND

Splanchnic vein thrombosis (SVT) is a well-recognized complication of acute pancreatitis. The question of whether or not to treat SVT with systemic therapeutic anticoagulation (STA) remains to be seen. The universal use of anticoagulation may lead to an increased risk of bleeding complications associated with acute pancreatitis. Literature on this subject is sparse and there is no clear guideline on how to treat SVT. Our research demonstrates local practice where therapeutic anticoagulation in SVT varies.

METHODS

A retrospective review of patients presenting with acute pancreatitis admitted over a five-year period to a single tertiary hospital with splanchnic vein thrombosis was performed.

RESULTS

Of the 1408 patients admitted with acute pancreatitis, 42 were diagnosed with splanchnic vein thrombosis, with a male dominance of 34 (81%). A total of 25 patients received anticoagulation. The use of anticoagulation was dependent on the location of the thrombus, P < 0.01. Anticoagulation use was most common in cases of combination mesenteric, splenic, and portal vein thrombus (100%), isolated mesenteric vein (100%), isolated portal vein (89%), combination portal and splenic vein (87%), and combination mesenteric and splenic vein (75%). The rate of anticoagulation use was lowest in isolated splenic vein thrombus (23%).

CONCLUSION

The early commencement of STA in patients with acute pancreatitis and triple-vessel SVT or with portal vein involvement is supported by our data. Isolated splenic vein thrombus does not require systemic therapy. Further research is needed to establish a clear clinical guideline.

Direct oral anticoagulants for the treatment of splanchnic vein thrombosis: A state of art

Splanchnic vein thrombosis (SVT) is a manifestation of venous thromboembolism in an unusual site. Portal, mesenteric, and splenic veins are the most common vessels involved in SVT which occurs mainly in patients with liver cirrhosis, although non-cirrhotic patients could be affected as well. Thrombosis of hepatic veins, also known as Budd-Chiari syndrome, is another manifestation of SVT. Prompt diagnosis and intervention are mandatory in order to increase the recalization rate and reduce the risk of thrombus progression and hypertensive complications. Traditional anticoagulation with heparin and vitamin-K antagonists is the treatment of choice in these cases. However, recent studies have shown promising results on the efficacy and safety of direct oral anticoagulants (DOACs) in this setting. Available results are mainly based on retrospective studies with small sample size, but first clinical trials have been published in the last years. This manuscript aims to provide an updated overview of the current evidence regarding the role of DOACs for SVT in both cirrhotic and non-cirrhotic patients.

Direct oral anticoagulants for the treatment of splanchnic vein thrombosis - A systematic review and meta-analysis

BACKGROUND

Splanchnic vein thrombosis (SVT) is an uncommon manifestation of venous thromboembolism in the splanchnic venous system, with scarce evidence surrounding its management. We assessed the efficacy and safety of direct oral anticoagulant (DOAC) to low-molecular-weight heparins (LMWH), vitamin-k antagonists (VKAs), or no anticoagulation.

METHODS

We conducted a systematic review and meta-analysis with the primary efficacy outcome being complete recanalization of affected vessels and primary safety outcome being major bleeding. Meta-analysis was done using a random-effects model, with dichotomous outcomes being synthesized with odds ratios (ORs) and corresponding 95 % CIs.

RESULTS

Seven non-randomized and one randomized study involving 883 participants were included for analysis. DOACs were more effective than VKAs (OR = 4.33; 95 % CI: 2.4, 7.83; n = 1 study) in non-cirrhotic patients and no anticoagulation in cirrhotic patients (OR = 3.86; 95 % CI: 1.49, 10.03; n = 3 studies). DOACs had a statistically significant reduction in major bleeding compared to observation [OR = 0.09; 95 % CI: 0.03, 0.29; n = 3 studies], LMWHs [OR = 0.13; 95 % CI: 0.03, 0.29; n = 1 study] and VKAs [OR = 0.12; 95 % CI: 0.02, 0.69; n = 2 studies] in non-cirrhotic patients. No difference in major bleeding was found between DOACs and observation, LMWH, or VKAs in cirrhotic patients.

CONCLUSION

DOACs appear to be a favorable alternative to VKAs and LMWHs in non-cirrhotic patients. This avenue of research would benefit from larger studies that adjust for SVT etiologies, patient risk factors, and overall bleeding risk.

Anticoagulant treatment for pediatric splanchnic vein thrombosis: a systematic review and meta-analysis

BACKGROUND

The clinical characteristics of splanchnic vein thrombosis (SVT) in pediatric patients and its optimal treatment strategies are unknown.

OBJECTIVES

This study aimed to assess the effectiveness and safety of anticoagulant therapy for pediatric SVT.

METHODS

MEDLINE and EMBASE databases were searched up to December 2021. We included observational and interventional studies that enrolled pediatric patients with SVT and reported anticoagulant treatment and outcomes, including rates of vessel recanalization, SVT extension, venous thromboembolism (VTE) recurrence, major bleeding, and mortality. Pooled proportions of vessel recanalization were calculated with their 95% CI.

RESULTS

A total of 506 pediatric patients (aged 0-18 years) across 17 observational studies were included. The majority of patients had portal vein thrombosis (n = 308, 60.8%) or Budd-Chiari syndrome (n = 175, 34.6%). Most events were triggered by transient provoking factors. Anticoagulation (heparins and vitamin K antagonists) was prescribed in 217 (42.9%) patients, and 148 (29.2%) patients underwent vascular interventions. The overall pooled proportions of vessel recanalization were 55.3% (95% CI, 34.1%-74.7%; I2 = 74.0%) among anticoagulated patients and 29.4% (95% CI, 2.6%-86.6%; I2 = 49.0%) among non-anticoagulated patients. SVT extension, major bleeding, VTE recurrence, and mortality rates were 8.9%, 3.8%, 3.5%, and 10.0%, respectively, in anticoagulated patients and 2.8%, 1.4%, 0%, and 50.3%, respectively, in non-anticoagulated patients.

CONCLUSION

In pediatric SVT, anticoagulation appears to be associated with moderate recanalization rates and a low risk of major bleeding. VTE recurrence is low and comparable to that reported in pediatric patients with other types of provoked VTE.

Catheter-directed thrombolysis versus systemic anticoagulation in the treatment of symptomatic splanchnic venous thrombosis secondary to acute pancreatitis: a retrospective cohort study

BACKGROUND

Catheter-directed thrombolysis (CDT) has been an important therapy and seems effective in patients with splanchnic venous thrombosis (SVT) secondary to some diseases, but this intervention hasn't been formally evaluated in the setting of acute pancreatitis (AP).

METHODS

This was a retrospective study enrolled patients between January 2013 and December 2018. AP patients who developed SVT-induced symptoms, including intractable ascites and/or enteral nutrition intolerance, were included. Demographics, SVT associated parameters, clinical features and outcomes, long-term quality of life evaluated by using SF-36 questionnaire were compared between CDT group and systemic anticoagulation (SAC) group.

RESULTS

6 patients underwent CDT and 17 received SAC. Patients in CDT group had a higher recanalization rate (100% versus 35.3%; p = 0.014) and shorter time to symptoms resolution (median 8 days versus. 31.5 days, p = 0.004). Mortality and length of hospital stay were comparable between two groups. The association analysis indicated that CDT use exerted a significantly beneficial effect on recanalization rate (risk ratio, 2.833; 95% CI, 1.489 to 5.393; p = 0.002) and time to symptoms resolution (mean difference, -33.333; 95% CI, -64.612 to -2.055; p = 0.038). No SVT-related symptoms recurrence was recorded in survivors at six-month follow-up. There was no statistical difference in either item of SF-36 questionnaire between two groups.

CONCLUSIONS

Compared with SAC, CDT may facilitate vascular recanalization and shorten symptom resolution for symptomatic SVT.

Outcome of Budd-Chiari Syndrome Patients Treated With Direct Oral Anticoagulants: An Austrian Multicenter Study

BACKGROUND AND AIMS

Direct oral anticoagulants (DOACs) may simplify management of Budd-Chiari syndrome (BCS). Here, we report our experience with off-label use of DOACs for anticoagulation in BCS.

METHODS

The safety of DOAC vs vitamin K antagonist treatment as well as associated clinical outcomes were retrospectively assessed in 47 BCS patients treated at 6 Austrian centers.

RESULTS

Mean age at study inclusion was 37.9 ± 14.0 years and mean Model for End-Stage Liver Disease was 13.1 ± 5.1. Overall, 63.8% (n = 30) of patients had decompensated liver disease, and 87.2% (n = 41) showed clinical signs of portal hypertension. During a median follow-up of 82.5 (interquartile range, 43.1-121.8) months, 43 (91.5%) patients received anticoagulation alone or following interventional treatment, including 22 (46.8%) patients treated with DOACs (edoxaban: 10, apixaban: 4, rivaroxaban: 3, dabigatran: 3, more than one DOAC sequentially: 2) for a median of 24.4 (interquartile range, 5.7-35.1) months. While 72.7% (n = 16 of 22) of patients were switched from low-molecular-weight heparin (n = 12) or vitamin K antagonist (n = 4) to DOAC after disease stabilization or improvement, 27.3% (n = 6 of 22) of BCS patients were initially treated with DOAC. Complete response (European Association for the Study of the Liver criteria) was achieved or maintained in 14 (63.6%) of 22 patients, with ongoing response in 2 patients, while disease progressed in 6 patients (including 2 patients with hepatocellular carcinoma). Four major spontaneous bleedings (18.2%; incidence rate 8.8 per 100 patient-years; n = 2 upper gastrointestinal bleeding, n = 1 lower gastrointestinal bleeding, n = 1 hepatocellular carcinoma rupture), 7 minor bleedings, and 1 major procedure-related bleeding (4.5%; 2.2 per 100 patient-years) occurred during DOAC therapy. Overall transplant-free survival was 91.6% at 5 years.

CONCLUSIONS

DOACs seem to be effective and safe for long-term anticoagulation in patients with BCS, but confirmation by larger prospective studies is needed.

A 10-year Australian experience of rare intraabdominal venous thrombosis with comparison to deep vein thrombosis and pulmonary embolism

OBJECTIVE

Intra-abdominal venous thromboembolism is rare with heterogeneous management. We aim to evaluate these thrombosis and compare them to deep vein thrombosis and/or pulmonary embolism.

METHOD

A 10-year retrospective evaluation of consecutive venous thromboembolism presentations (January 2011-December 2020) at Northern Health, Australia, was conducted. A subanalysis of intraabdominal venous thrombosis involving splanchnic, renal and ovarian veins was performed.

RESULTS

There were 3343 episodes including 113 cases of intraabdominal venous thrombosis (3.4%) - 99 splanchnic vein thrombosis, 10 renal vein thrombosis and 4 ovarian vein thrombosis. Of the splanchnic vein thrombosis presentations, 34 patients (35 cases) had known cirrhosis. Patients with cirrhosis were numerically less likely to be anticoagulated compared to noncirrhotic patients (21/35 vs. 47/64, P  = 0.17). Noncirrhotic patients ( n  = 64) were more likely to have malignancy compared to those with deep vein thrombosis and/or pulmonary embolism (24/64 vs. 543/3230, P  < 0.001), including 10 patients diagnosed at time of splanchnic vein thrombosis presentation. Cirrhotic patients reported more recurrent thrombosis/clot progression (6/34) compared to noncirrhotic patients (3/64) (15.6 vs. 2.3 events/100-person-years; hazard ratio 4.7 (95% confidence interval 1.2-18.9), P  = 0.030) and other venous thromboembolism patients (2.6/100-person-years; hazard ratio 4.7, 95% confidence interval 2.1-10.7; P  < 0.001) with comparable major bleeding rates. All renal vein thrombosis were provoked including five malignant-related cases while three ovarian vein thrombosis occurred postpartum. No recurrent thrombotic or bleeding complications were reported in renal vein thrombosis and ovarian vein thrombosis.

CONCLUSION

These rare intraabdominal venous thromboses are often provoked. Splanchnic vein thrombosis (SVT) patients with cirrhosis have a higher rate of thrombotic complications, while SVT without cirrhosis was associated with more malignancy. Given the concurrent comorbidities, careful assessment and individualized anticoagulation decision is needed.

Oral Anticoagulation in Patients with Chronic Liver Disease

The administration of an anticoagulant in patients with liver disease (nonalcoholic steatohepatitis-NASH, nonalcoholic fatty liver disease-NAFLD, chronic hepatitis, or cirrhosis) who have an indication (atrial fibrillation, venous thrombosis, or pulmonary embolism) is challenging because there is an imbalance between thrombosis and bleeding. There is a need to focus our attention on preventing risk factors because diabetes, obesity, dyslipidemia, smoking, and sedentary behavior are risk factors for both NASH/NAFLD and AF, and these patients require anticoagulant treatment. Patients with advanced liver disease (Child-Pugh C) were excluded from studies, so vitamin K antagonists (VKAs) are still recommended. Currently, VKAs are recommended for other conditions (antiphospholipid syndrome, mitral valve stenosis, and mechanical valve prosthesis). Amongst the patients under chronic anticoagulant treatment, especially for the elderly, bleeding as a result of the improper use of warfarin is one of the important causes of emergency admissions due to adverse reactions. DOACs are considered to be efficient and safe, with apixaban offering superior protection against stroke and a good safety profile as far as major bleeding is concerned compared to warfarin. DOACs are safe in the Child-Pugh A and B classes (except rivaroxaban), and in the Child-Pugh C class are contraindicated. Given that there are certain and reliable data for chronic kidney disease regarding the recommendations, in liver function impairment more randomized studies must be carried out, as the current data are still uncertain. In particular, DOACs have a simple administration, minimal medication interactions, a high safety and effectiveness profile, and now a reversal agent is available (for dabigatran and idarucizumab). Patients are also statistically more compliant and do not require INR monitoring.

Anticoagulant therapy for splanchnic vein thrombosis: recent updates for patients with liver cirrhosis

INTRODUCTION

Liver cirrhosis is accompanied by several hemostatic alterations, which contribute to the current theory of "rebalanced hemostasis." Splanchnic vein thrombosis (SVT) is a frequent complication of liver cirrhosis (17-26% of the cirrhotic patients), and liver cirrhosis is a common risk factor for SVT (24-28% of SVT cases).

AREAS COVERED

This narrative review aims to describe the current state of the art on the anticoagulant treatment of cirrhotic SVT, with a particular focus on the possible role of the direct oral anticoagulants (DOACs) and recent guidelines on this topic.

EXPERT OPINION

Early anticoagulant therapy is recommended in cirrhotic patients with acute SVT, to obtain vessel recanalization and decrease the rates of portal hypertension-related complications. Gastroesophageal varices do not represent a contraindication to anticoagulation, if adequate prophylaxis of variceal bleeding is established, and varices band ligation can be safely performed without the need to stop the anticoagulant treatment. The conventional treatment of cirrhotic SVT consisted of low molecular weight heparin, as initial treatment of choice, eventually followed by vitamin K antagonists, but the DOACs can be considered as a reasonable alternative in patients with compensated liver cirrhosis.

Efficacy and safety of thrombolytic therapy for portal venous system thrombosis: A systematic review and meta-analysis

BACKGROUND AND AIMS

The role of thrombolytic therapy in patients with portal venous system thrombosis (PVST) remains ambiguous. This study aimed to systematically collect available evidence and evaluate the efficacy and safety of thrombolysis for PVST.

METHODS

Eligible studies were searched via PubMed, EMBASE, and Cochrane Library databases. Among the cohort studies, meta-analyses were performed to assess the outcomes of PVST patients receiving thrombolysis. Pooled proportions were calculated. Among the case reports and case series, logistic regression analyses were performed to identify the risk factors for outcomes of PVST patients receiving thrombolysis. Odds ratios (ORs) were calculated.

RESULTS

Among the 2134 papers initially identified, 29 cohort studies and 131 case reports or case series were included. Based on the cohort studies, the pooled rates of overall response to thrombolytic therapy, complete recanalization of PVST, bleeding events during thrombolysis, further bowel resection, thrombosis recurrence, and 30-day mortality were 93%, 58%, 18%, 3%, 1%, and 4%, respectively. Based on the case reports and case series, acute pancreatitis (OR = 0.084), history of liver transplantation (OR = 13.346), and interval between onset of symptoms and initiation of thrombolysis ≤14 days (OR = 3.105) were significantly associated with complete recanalization of PVST; acute pancreatitis (OR = 6.556) was significantly associated with further bowel resection; but no factors associated with the overall response to thrombolytic therapy, bleeding events during thrombolysis, thrombosis recurrence, and 30-day mortality were identified or could be calculated.

CONCLUSION

Early initiation of thrombolysis should be effective for the treatment of PVST. But its benefits for PVST secondary to acute pancreatitis are weakened.

Shedding Light on the Pathogenesis of Splanchnic Vein Thrombosis

Splanchnic vein thrombosis is a rare but potentially life-threatening manifestation of venous thromboembolism, with challenging implications both at the pathological and therapeutic level. It is frequently associated with liver cirrhosis, but it could also be provoked by myeloproliferative disorders, cancer of various gastroenterological origin, abdominal infections and thrombophilia. A portion of splanchnic vein thrombosis is still classified as idiopathic. Here, we review the mechanisms of splanchnic vein thrombosis, including new insights on the role of clonal hematopoiesis in idiopathic SVT pathogenesis, with important implications from the therapeutic standpoint.

Splanchnic Vein Thrombosis in Myeloproliferative Neoplasms: Treatment Considerations and Unmet Needs

Patients who develop splanchnic vein thrombosis (SVT) in the setting of a myeloproliferative neoplasm (MPN) are at risk for complications including portal hypertension, bleeding, thrombosis, and death. Prompt multidisciplinary treatment is thus necessary to prevent long-term sequelae. However, optimal management strategies are not well established due to a paucity of data. In this review, we very briefly discuss the epidemiology, pathophysiology, and prognosis of MPN-SVT and then more comprehensively explore treatment considerations of MPN-SVT, including anticoagulation, endovascular/surgical intervention, and cytoreductive therapy. We will also highlight current gaps in our knowledge of MPN-SVT and conclude by suggesting future directions to optimize the treatment of MPN-SVT and improve outcomes.

Portal Vein Thrombosis in the Setting of Cirrhosis: A Comprehensive Review

Portal vein thrombosis constitutes the most common thrombotic event in patients with cirrhosis, with increased rates in the setting of advanced liver disease. Despite being a well-known complication of cirrhosis, the contribution of portal vein thrombosis to hepatic decompensation and overall mortality is still a matter of debate. The incorporation of direct oral anticoagulants and new radiological techniques for portal vein recanalization have expanded our therapeutic arsenal. However, the lack of large prospective observational studies and randomized trials explain the heterogenous diagnostic and therapeutic recommendations of current guidelines. This article seeks to make a comprehensive review of the pathophysiology, clinical features, diagnosis, and treatment of portal vein thrombosis in patients with cirrhosis.

Consensus Statement on Hemostatic Management, Anticoagulation, and Antiplatelet Therapy in Liver Transplantation

Anticoagulation and antiplatelet therapies are increasingly used in liver transplant (LT) candidates and recipients due to cardiovascular comorbidities, portal vein thrombosis, or to manage posttransplant complications. The implementation of the new direct-acting oral anticoagulants and the recently developed antiplatelet drugs is a great challenge for transplant teams worldwide, as their activity must be monitored and their complications managed, in the absence of robust scientific evidence. In this changing and clinically heterogeneous scenario, the Spanish Society of Liver Transplantation and the Spanish Society of Thrombosis and Haemostasis aimed to achieve consensus regarding the indications, drugs, dosing, and timing of anticoagulation and antiplatelet therapies initiated from the inclusion of the patient on the waiting list to post-LT surveillance. A multidisciplinary group of experts composed by transplant hepatologists, surgeons, hematologists, transplant-specialized anesthesiologists, and intensivists performed a comprehensive review of the literature and identified 21 clinically relevant questions using the patient-intervention-comparison-outcome format. A preliminary list of recommendations was drafted and further validated using a modified Delphi approach by a panel of 24 transplant delegates, each representing a LT institution in Spain. The present consensus statement contains the key recommendations together with the core supporting scientific evidence, which will provide guidance for improved and more homogeneous clinical decision making.

Anticoagulant therapy for splanchnic vein thrombosis: an individual patient data meta-analysis

Robust evidence on the optimal management of splanchnic vein thrombosis (SVT) is lacking. We conducted an individual patient meta-analysis to evaluate the effectiveness and safety of anticoagulation for splanchnic vein thrombosis (SVT). MEDLINE, EMBASE, and clincaltrials.gov., were searched up to June 2021 for prospective cohorts or randomized clinical trials including patients with SVT. Data from individual datasets were merged, and any discrepancy with published data was resolved by contacting study authors. Three studies for a total of 1635 patients were included. Eighty-five percent of patients received anticoagulation for a median duration of 316 days (range 1 to 730 days). Overall, incidence rates for recurrent VTE, major bleeding, and mortality were 5.3/100 patients-years (p-y) (95% CI, 5.1 to 5.5), 4.4/100 p-y (95% CI, 4.2 to 4.6), and 13.0/100 p-y (95% CI, 12.4 to 13.6), respectively. The incidence rates of all outcomes were lower during anticoagulation and higher after treatment discontinuation or when anticoagulation was not administered. In multivariable analysis, anticoagulant treatment appeared to be associated with a lower risk of recurrent VTE (Hazard Ratio [HR] 0.42; 95% CI, 0.27 to 0.64), major bleeding (HR 0.47; 95% CI, 0.30 to 0.74), and mortality (HR 0.23; 95% CI, 0.17 to 0.31). Results were consistent in patients with cirrhosis, solid cancer, myeloproliferative neoplasms, unprovoked SVT, and SVT associated with transient or persistent non-malignant risk factors. In patients with SVT the risk of recurrent VTE and major bleeding is substantial. Anticoagulant treatment is associated with reduced risk of both outcomes.

Rivaroxaban for the treatment of noncirrhotic splanchnic vein thrombosis: an interventional prospective cohort study

SVT is a potentially life-threatening disease associated with a substantial risk of recurrence and bleeding.

Rivaroxaban appears to be a reasonable alternative to standard anticoagulation for the treatment of SVT in patients without cirrhosis.

Heparins and vitamin K antagonists are the mainstay of treatment of splanchnic vein thrombosis (SVT). Rivaroxaban is a potential alternative, but data to support its use are limited. We aimed to evaluate the safety and efficacy of rivaroxaban for the treatment of acute SVT. In an international, single-arm clinical trial, adult patients with a first episode of noncirrhotic, symptomatic, objectively diagnosed SVT received rivaroxaban 15 mg twice daily for 3 weeks, followed by 20 mg daily for an intended duration of 3 months. Patients with Budd-Chiari syndrome and those receiving full-dose anticoagulation for >7 days prior to enrollment were excluded. Primary outcome was major bleeding; secondary outcomes included death, recurrent SVT, and complete vein recanalization within 3 months. Patients were followed for a total of 6 months. A total of 103 patients were enrolled; 100 were eligible for the analysis. Mean age was 54.4 years; 64% were men. SVT risk factors included abdominal inflammation/infection (28%), solid cancer (9%), myeloproliferative neoplasms (9%), and hormonal therapy (9%); 43% of cases were unprovoked. JAK2 V617F mutation was detected in 26% of 50 tested patients. At 3 months, 2 patients (2.1%; 95% confidence interval, 0.6-7.2) had major bleeding events (both gastrointestinal). One (1.0%) patient died due to a non–SVT-related cause, 2 had recurrent SVT (2.1%). Complete recanalization was documented in 47.3% of patients. One additional major bleeding event and 1 recurrent SVT occurred at 6 months. Rivaroxaban appears as a potential alternative to standard anticoagulation for the treatment of SVT in non-cirrhotic patients. This trial was registered at www.clinicaltrials.gov as #NCT02627053 and at eudract.ema.europa.eu as #2014-005162-29-36.

Antithrombotic Therapy After Venous Interventions: AJR Expert Panel Narrative Review

Interventions for thrombotic and nonthrombotic venous disorders have increased with technical advances and more trained venous specialists. Antithrombotic therapy is essential to clinical and procedural success; however, post-procedural therapeutic regimens exhibit significant heterogeneity due to limited prospective randomized data as well as incomplete mechanistic understanding of the critical factors driving long-term patency. Post-interventional antithrombotic therapy for thrombotic venous disorders should adhere to existing venous thromboembolism management guidelines, which include 3-6 months of therapeutic anticoagulation at minimum and consideration of extended therapy in patients with higher risk of thrombosis due to procedural or patient factors. The additive benefit of antiplatelet agents in the acute and intermediate period is unknown, having shown improved long-term stent patency in some retrospective studies. Dual and/or triple agent therapy should be limited based on individual risks of thrombosis and bleeding. The treatment of non-thrombotic disorders is more heterogeneous, though patients with limited flow, extensive stent material, or underlying prothrombotic states such as malignancy or chronic inflammation may benefit from single- or multi-agent antithrombotic therapy. However, the agent, dose, and duration of therapy remain indeterminate. Future prospective studies are warranted to improve patient risk stratification and standardize post-procedural antithrombotic therapy in patients receiving venous interventions.

Treatment of Atypical Clots

The term unusual site thrombosis refers to the occurrence of venous thromboembolism outside of the lower limbs and the pulmonary arteries. Unusual site thrombosis can virtually affect any venous segment, with the most common and/or clinically relevant sites including the upper limbs veins, the retinal veins, the splanchnic veins and the cerebral veins. Clinical features are obviously heterogeneous, while many predisposing factors are common, though with different prevalence among the various disorders. Antithrombotic therapy is prescribed to most patients, but the type, intensity, and duration of treatment vary both within and among patient groups. Increasing evidence is supporting the use of the direct oral anticoagulants in patients with upper limb deep vein thrombosis, cerebral vein thrombosis, and with splanchnic vein thrombosis. This article will review available evidence on the treatment of venous thrombosis occurring in unusual sites.

Clots in unusual places: lots of stress, limited data, critical decisions

Although much less common than deep vein thrombosis of the lower extremities or lungs, clots in unusual locations, including the splanchnic, cerebral, retinal, upper-extremity, and renal locations, present with significant morbidity and mortality. In the last 2 decades, treatment of clots in these unusual locations is primarily managed medically, with interventional and surgical approaches reserved for more severe or refractory cases. The hematologist is well positioned to provide consultation to organ-specific specialties (ie, neurosurgery, hepatology, ophthalmology), especially because acquired and congenital hypercoagulability plays a major role, and anticoagulation is often the primary treatment. Historically, treatment has been based on expert opinion, but systematic reviews and meta-analyses have recently been published. Various societies have produced guidelines for the treatment of clots in unusual locations; however, randomized clinical trial data remain scarce. In the last few years, increasing data have emerged concerning the efficacy of the direct oral anticoagulants in treating clots in unusual locations. Cases have recently been described highlighting atypical thrombosis associated with COVID-19 infection as well as with the ChAdOx1 nCoV-19 (AstraZeneca) vaccine and Johnson and Johnson's Janssen Ad26.COV2.S vaccine. This article reviews clots in unusual locations with an emphasis on the splanchnic (mesenteric, portal, splenic, hepatic) and cerebral circulation. Through a case-based approach, key questions are posed, and data are presented to help guide diagnosis and treatment.

Evidence-Based Minireview: Should warfarin or a direct oral anticoagulant be used in patients presenting with thrombosis in the splanchnic or cerebral veins?

Case 1: A 23-year-old female third-year medical student who has no medical history seeks treatment for abdominal distention. She takes an estrogen-containing birth control pill and does not smoke or consume alcohol. Family history is unremarkable. Physical examination is significant for abdominal distention, and an abdominal fluid wave is detected. Complete blood count is normal. Imaging confirms occlusive thrombosis of the main portal vein. On endoscopy, grade 1 to 2 esophageal varices are noted and banded. Unfractionated heparin is begun. Subsequent workup reveals a homozygous factor V Leiden mutation. Long-term anticoagulation is planned, and she asks if warfarin can be avoided given her hectic ward rotations, erratic diet, and need for monitoring. Case 2: A 35-year-old woman who has no medical history seeks treatment for progressively worsening posterior headaches for 1 week. Magnetic resonance imaging of the brain shows dural sinus thrombosis with associated small areas of petechial cerebral hemorrhage. She is started on a continuous unfractionated heparin infusion and admitted to the hospital for further observation. Her grandmother is on warfarin for atrial fibrillation, and the patient would prefer to avoid warfarin because she does not think she can comply with the frequent monitoring that will be required. She inquires about other oral anticoagulant options for her condition.

Essential Thrombocythemia in Children and Adolescents

Simple Summary

Among chronic Ph-negative myeloproliferative neoplasms, essential thrombocythemia is found in children with low but increasing incidence. The diagnostic and clinical features do not completely overlap with ET of adult age. A significant number of cases, in fact, do not meet the criteria of clonality, and many cases require extensive clinical evaluation to exclude secondary, reactive forms. Therefore, histological analysis of bone marrow biopsy is necessary, and its use should be enforced. The clinical course appears to be more benign, at least within the first decades of observation, with the incidence of thrombotic events being much lower than in adults (4 % vs. 30%). Hemorrhages are mostly irrelevant. Therefore, the management should be carefully adapted to the individual patient, balancing the risk of future complications with long-term collateral effects of any drug. This review analyzes the peculiarities of the disease facing similarities and differences with adult scenarios.

Abstract

This paper reviews the features of pediatric essential thrombocythemia (ET). ET is a rare disease in children, challenging pediatric and adult hematologists alike. The current WHO classification acknowledges classical Philadelphia-negative MPNs and defines diagnostic criteria, mainly encompassing adult cases. The presence of one of three driver mutations (JAK2V617F, CALR, and MPL mutations) represent the proof of clonality typical of ET. Pediatric ET cases are thus usually confronted by adult approaches. These can fit only some patients, because only 25–40% of cases present one of the driver mutations. The diagnosis of hereditary, familial thrombocytosis and the exclusion of reactive/secondary thrombocytosis must be part of the diagnostic process in children and can clarify most of the negative cases. Still, many children present a clinical, histological picture of ET, with a molecular triple wild-type status. Moreover, prognosis seems more benign, at least within the first few decades of follow-up. Thrombotic events are rare, and only minor hemorrhages are ordinarily observed. As per the management, the need to control symptoms must be balanced with the collateral effects of lifelong drug therapy. We conclude that these differences concert a compelling case for a very careful therapeutic approach and advocate for the importance of further cooperative studies.

Vaccine-induced immune thrombotic thrombocytopenia

In response to the COVID-19 pandemic, vaccines for SARS-CoV-2 were developed, tested, and introduced at a remarkable speed. Although the vaccine introduction had a major impact on the evolution of COVID-19, some potential rare side-effects of the vaccines were observed. Within a short period, three scientific groups from Norway, Germany, and the UK reported cerebral venous sinus thrombosis with thrombocytopenia and anti-platelet factor 4 (anti-PF4) antibodies in individuals following AstraZeneca–Oxford vaccination and named this new syndrome vaccine-induced immune thrombotic thrombocytopenia (VITT). This syndrome was subsequently reported in individuals who received Johnson & Johnson vaccination. In this Viewpoint, we discuss the epidemiology, pathophysiology, and optimal diagnostic and therapeutic management of VITT. Presentation of an individual with possible VITT should raise prompt testing for anti-PF4 antibodies and initiation of treatment targeting autoimmune processes with intravenous immunoglobulin and prothrombotic processes with non-heparin anticoagulation.

Anticoagulant therapy for splanchnic vein thrombosis: a systematic review and meta-analysis

Treatment of splanchnic vein thrombosis (SVT) is challenging, and evidence to guide therapeutic decisions remains scarce. The objective of this systematic review and meta-analysis was to determine the efficacy and safety of anticoagulant therapy for SVT. MEDLINE, EMBASE, and clinicaltrials.gov were searched from inception through December 2019, without language restrictions, to include observational studies and randomized controlled trials reporting radiological or clinical outcomes in patients with SVT. Pooled proportions and risk ratios (RRs) with 95% confidence intervals (CIs) were calculated in a random-effects model. Of 4312 records identified by the search, 97 studies including 7969 patients were analyzed. In patients receiving anticoagulation, the rates of SVT recanalization, SVT progression, recurrent venous thromboembolism (VTE), major bleeding, and overall mortality were 58% (95% CI, 51-64), 5% (95% CI, 3-7), 11% (95% CI, 8-15), 9% (95% CI, 7-12), and 11% (95% CI, 9-14), respectively. The corresponding values in patients without anticoagulation were 22% (95% CI, 15-31), 15% (95% CI, 8-27), 14% (95% CI, 9-21), 16% (95% CI, 13-20), and 25% (95% CI, 20-31). Compared with no treatment, anticoagulant therapy obtained higher recanalization (RR, 2.39; 95% CI, 1.66-3.44) and lower thrombosis progression (RR, 0.24; 95% CI, 0.13-0.42), major bleeding (RR, 0.73; 95% CI, 0.58-0.92), and overall mortality (RR, 0.45; 95% CI, 0.33-0.60). These results demonstrate that anticoagulant therapy improves SVT recanalization and reduces the risk of thrombosis progression without increasing major bleeding. The incidence of recurrent VTE remained substantial in patients receiving anticoagulation, as well. Effects were consistent across the different subgroups of patients. This trial was registered on the PROPERO database at (https://www.crd.york.ac.uk/prospero//display_record.php?ID=CRD42019127870) as #CRD42019127870.

Illustrated State-of-the-Art Capsules of the ISTH 2020 Congress

This year's Congress of the International Society of Thrombosis and Haemostasis (ISTH) was hosted virtually from Philadelphia July 17-21, 2021. The conference, now held annually, highlighted cutting-edge advances in basic, population and clinical sciences of relevance to the Society. Despite being held virtually, the 2021 congress was of the same scope and quality as an annual meeting held in person. An added feature of the program is that talks streamed at the designated times will then be available on-line for asynchronous viewing. The program included 77 State of the Art (SOA) talks, thematically grouped in 28 sessions, given by internationally recognized leaders in the field. The SOA speakers were invited to prepare brief illustrated reviews of their talks that were peer reviewed and are included in this article. The topics, across the main scientific themes of the congress, include Arterial Thromboembolism, Coagulation and Natural Anticoagulants, COVID-19 and Coagulation, Diagnostics and Omics, Fibrinogen, Fibrinolysis and Proteolysis, Hemophilia and Rare Bleeding Disorders, Hemostasis in Cancer, Inflammation and Immunity, Pediatrics, Platelet Disorders, von Willebrand Disease and Thrombotic Angiopathies, Platelets and Megakaryocytes, Vascular Biology, Venous Thromboembolism and Women's Health. These illustrated capsules highlight the major scientific advances with potential to impact clinical practice. Readers are invited to take advantage of the excellent educational resource provided by these illustrated capsules. They are also encouraged to use the image in social media to draw attention to the high quality and impact of the science presented at the congress.

Cancer-Associated Splanchnic Vein Thrombosis

Splanchnic vein thrombosis (SVT), which includes portal, mesenteric, and splenic vein thrombosis and the Budd-Chiari syndrome, is an infrequent manifestation of venous thromboembolism (VTE). Like typical site VTE, SVT is also frequently associated with cancer, particularly intra-abdominal solid malignancies and myeloproliferative neoplasms (MPNs). The clinical presentation of SVT is nonspecific. Symptoms may be related to the underlying malignancy, and thrombosis is incidentally diagnosed by imaging studies for cancer staging or follow-up in a substantial proportion of cases. The occurrence of SVT predicts worse prognosis in patients with liver or pancreatic cancer and, not uncommonly, SVT may precede the diagnosis of cancer. Therefore, the occurrence of an apparently unprovoked SVT should prompt careful patient evaluation for the presence of an underlying malignancy or MPN. Cancer patients carry a high risk of VTE extension and recurrence and long-term anticoagulant treatment is suggested in the absence of high risk of bleeding. Either LMWH or direct oral anticoagulants (DOACs) are suggested for the treatment of patients with cancer-related SVT, although limited experience is available on the use of DOACs in these settings. Vitamin K antagonists (VKAs) are suggested for the short and long-term treatment of SVT associated with MPN. This review outlines the epidemiological aspects, pathogenesis, risk factors, and diagnosis of cancer-associated SVT, and addresses questions regarding the management of this challenging condition.

Failure of the Ottawa Score to Predict the Risk of Recurrent Venous Thromboembolism in Cancer Patients: The Prospective PREDICARE Cohort Study

INTRODUCTION

 Recurrent venous thromboembolism (VTE) despite curative anticoagulation is frequent in patients with cancer. Identifying patients with a high risk of recurrence could have therapeutic implications. A prospective study was designed to validate the Ottawa risk score of recurrent VTE in cancer patients.

METHODS

 In a prospective multicenter observational cohort, adult cancer patients with a recent diagnosis of symptomatic or incidental lower limb deep vein thrombosis or pulmonary embolism (PE) were treated with tinzaparin for 6 months. The primary endpoint was the recurrence of symptomatic or asymptomatic VTE within the first 6 months of treatment. All clinical events were centrally reviewed and adjudicated. Time-to-event outcomes were estimated by the Kalbfleisch and Prentice method to take into account the competing risk of death. A C-statistic value of > 0.70 was needed to validate the Ottawa score.

RESULTS

 A total of 409 patients were included and analyzed on an intention-to-treat basis. Median age was 68 years, 60.4% of patients had PE, and VTE was symptomatic in 271 patients (66.3%). The main primary sites were lung (31.3%), lower digestive tract (14.4%), and breast (13.9%) cancers. The Ottawa score was high (≥ 1) in 58% of patients. The 6-month cumulative incidence of recurrent VTE was 7.3% (95% confidence interval [CI]: 4.9-11.1) overall, and 5.0% (95% CI: 2.3-10.8) versus 9.1% (95%CI: 6.1-13.6) in the Ottawa low versus high risk groups, respectively. The C-statistic value was 0.60 (95% CI: 0.55-0.65).

CONCLUSION

 In this prospective cohort of patients with cancer receiving tinzaparin for VTE, the Ottawa score failed to accurately predict recurrent VTE.

Treatment of portal vein thrombosis: an updated narrative review

Portal vein thrombosis (PVT) is the most frequent among the splanchnic vein thrombosis, accounting for 90% of cases. More than half of PVT are provoked by liver cirrhosis, solid cancer or myeloproliferative neoplasms. The remaining cases are non-malignant non-cirrhotic PVT and include either unprovoked events or thrombosis secondary to other less common risk factors (e.g. abdominal surgery, intrabdominal inflammations/infections, or hormonal stimuli). Anticoagulant therapy in patients with acute symptomatic PVT should be started early after diagnosis, if no active bleeding, to obtain greater vessel recanalization and reduce the occurrence of portal-hypertension related complications. Gastroesophageal varices do not represent a contraindication to anticoagulant treatment, as long as adequate measures have been undertaken for the prophylaxis of gastroesophageal bleeding. Different treatment options (unfractionated or low molecular weight heparin, vitamin K antagonists and direct oral anticoagulants [DOACs]) can be considered. In this narrative review we will discuss the treatment of PVT in the three most common scenarios (cirrhosis-associated, cancer-associated and non-malignant non-cirrhotic PVT). We will also discuss the role of the DOACs and summarise recent guidelines on this topic.

Clinical history of cancer-associated splanchnic vein thrombosis

BACKGROUND

Cancer represents a risk factor for splanchnic vein thrombosis (SVT) and usual site venous thromboembolism (VTE).

OBJECTIVES

To compare characteristics and outcomes of patients with cancer-associated SVT and usual site VTE.

PATIENTS/METHODS

Patients with solid cancer and SVT were enrolled in an international, prospective registry between May 2008 and January 2012. The comparison cohort included (1:1 ratio) patients with solid cancer and usual site VTE treated at two thrombosis centers who had a minimum of 12 months follow-up at December 2019 or experienced one of the outcomes within 12 months follow-up. Recurrent VTE, major bleeding, and all-cause mortality were evaluated at 12-month follow-up.

RESULTS

A total of 264 patients (132 in each cohort) were enrolled. Patients with SVT were less likely to have metastatic disease (36.1% vs 72.5%) or receive cancer therapy at thrombosis diagnosis (29.6% vs 64.9%). The most frequent cancer types were hepatobiliary and pancreatic in the SVT cohort and gastrointestinal in the usual site VTE cohort. Fewer patients with SVT received anticoagulation (68.9% vs 99.2%), and treatment duration was shorter (6.0 vs 11.0 months). The cumulative incidence of major bleeding (2.3% vs 4.7%) was nonsignificantly lower in the SVT cohort, whereas recurrent thrombosis (4.7% vs 5.5%) and all-cause mortality (41.7% vs 39.4%) were comparable between the two cohorts.

CONCLUSIONS

The risk of recurrent thrombosis and bleeding appears to be similar in cancer patients with SVT and cancer patients with usual site VTE, despite some differences in baseline characteristics and anticoagulant treatment. Further prospective studies are warranted to confirm these findings.