How I treat splanchnic vein thrombosis

A retrospective multicentre clinical study on management of isolated splenic vein thrombosis: risks and benefits of anticoagulation

INTRODUCTION

Isolated splenic vein thrombosis (iSVT) is a common complication of pancreatic disease. Whilst patients remain asymptomatic, there is a risk of sinistral portal hypertension and subsequent bleeding from gastric varices if recanalisation does not occur. There is wide variation of iSVT treatment, even within single centres. We report outcomes of iSVT from tertiary referral hepatobiliary and pancreatic (HPB) units including the impact of anticoagulation on recanalisation rates and subsequent variceal bleeding risk.

METHODS

A retrospective cohort study including all patients diagnosed with iSVT on contrast-enhanced CT scan abdomen and pelvis between 2011 and 2019 from two institutions. Patients with both SVT and portal vein thrombosis at diagnosis and isolated splenic vein thrombosis secondary to malignancy were excluded. The outcomes of anticoagulation, recanalisation rates, risk of bleeding and progression to portal vein thrombosis were examined using CT scan abdomen and pelvis with contrast.

RESULTS

Ninety-eight patients with iSVT were included, of which 39 patients received anticoagulation (40%). The most common cause of iSVT was acute pancreatitis n = 88 (90%). The recanalisation rate in the anticoagulation group was 46% vs 15% in patients receiving no anticoagulation (p = 0.0008, OR = 4.7, 95% CI 1.775 to 11.72). Upper abdominal vascular collaterals (demonstrated on CT scan angiography) were significantly less amongst patients who received anticoagulation treatment (p = 0.03, OR = 0.4, 95% CI 0.1736 to 0.9288). The overall rate of upper GI variceal-related bleeding was 3% (n = 3/98) and it was independent of anticoagulation treatment. Two of the patients received therapeutic anticoagulation.

CONCLUSION

The current data supports that therapeutic anticoagulation is associated with a statistically significant increase in recanalisation rates of the splenic vein, with a subsequent reduction in radiological left-sided portal hypertension. However, all patients had a very low risk of variceal bleeding regardless of anticoagulation. The findings from this retrospective study should merit further investigation in large-scale randomised clinical trials.

Intestinal Obstruction as Initial Presentation of Idiopathic Portal and Mesenteric Venous Thrombosis: Diagnosis, Management, and Literature Review

It is quite common for portal vein thrombosis to occur in subjects who present predisposing conditions such as cirrhosis, hepatobiliary malignancies, infectious or inflammatory abdominal diseases, or hematologic disorders. The incidence of idiopathic portal vein thrombosis in non-cirrhotic patients remains low, and despite the intensive workup that is performed in these cases, in up to 25% of cases, there is no identifiable cause. If portal vein thrombosis is untreated, complications arise and include portal hypertension, cavernous transformation of the portal vein, gastroesophageal and even small intestinal varices, septic thrombosis, or intestinal ischemia. However, intestinal ischemia develops as a consequence of arterial thrombosis or embolism, and the thrombosis of the mesenteric vein accounts for about 10% of cases of intestinal ischemia. Although acute superior mesenteric vein thrombosis can cause acute intestinal ischemia, its chronic form is less likely to cause acute intestinal ischemia, considering the possibility of developing collateral drainage. Ileus due to mesenteric venous thrombosis is rare, and only a small number of cases have been reported to date. Most patients experience a distinct episode of acute abdominal pain due to ischemia, and in the second phase, they develop an obstruction/ileus. Acute superior mesenteric venous thrombosis is a rare condition that is still associated with a high mortality rate. The management of such cases of superior mesenteric venous thrombosis is clinically challenging due to their insidious onset and rapid development. A prompt and accurate diagnosis followed by a timely surgical treatment is important to save patient lives, improve the patient survival rate, and conserve as much of the patient's bowel as possible, thus leading to fewer sequelae.

Do we need more guidance on thrombophilia testing? Challenges and special considerations

INTRODUCTION

Thrombophilia testing (TT) is a laboratory procedure designed to detect the risk factors involved in the pathogenesis of vascular occlusions. The role of TT is also controversial because it has a limited impact on the choice and duration of antithrombotic treatments.

AREAS COVERED

We reviewed, by examining MEDLINE up to October 2023. Accepted and not accepted thrombophilia markers are discussed along with the appropriateness or not of prescribing TT in several conditions such as: provoked and unprovoked venous thromboembolism (VTE), women who are planning a pregnancy whose relatives had VTE or have a hereditary thrombophilia, before assumption of estro-progestins, after multiple pregnant loss, arterial thrombosis, retinal vein occlusion, and splanchnic vein thrombosis.

EXPERT OPINION

TT is not essential in the management of VTE, but it may be useful for limiting adverse events in case of thrombophilia. We expose our criticism of items afforded by other guidelines by presenting our opinion based on both the scientific evidence and clinical practice. We also deal with common mistakes in prescribing and interpretations of TT hoping to purpose an educational approach on this topic. Finally, we emphasize the creation of the expert in hemostasis and thrombosis who should be present in every hospital.

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 Myelofibrosis-An Underappreciated Hallmark of Disease Phenotype

Splanchnic vein thrombosis (SVT) encompasses thrombosis in the vessels of the splanchnic basin and has a relatively rare occurrence with a reported frequency in the general population of 1-2%. An episode of seemingly unprovoked SVT almost always triggers a diagnostic work-up for a Philadelphia chromosome-negative myeloproliferative neoplasm (MPN), since atypical site thrombosis is a hallmark of MPN-associated thrombophilia. Primary myelofibrosis (PMF) is a rare MPN with an estimated incidence between 0.1 and 1/100,000 per year. Although prothrombotic tendency in PMF is not envisioned as a subject of specific therapeutic management, unlike other MPNs, such as polycythemia vera (PV) and essential thrombocythemia (ET), thrombotic risk and SVT prevalence in PMF may be comparably high. Additionally, unlike PV and ET, SVT development in PMF may depend more on procoagulant mechanisms involving endothelium than on blood cell activation. Emerging results from registry data also suggest that PMF patients with SVT may exhibit lower risk and better prognosis, thus highlighting the need for better thrombotic risk stratification and identifying a subset of patients with potential benefit from antithrombotic prophylaxis. This review highlights specific epidemiological, pathogenetic, and clinical features pertinent to SVT in myelofibrosis.

Essential Thrombocythemia in Adolescents and Young Adults: Clinical Aspects, Treatment Options and Unmet Medical Needs

OPINION STATEMENT

Current treatment of essential thrombocythemia (ET) should primarily prevent thrombo-hemorrhagic events, without increasing the rate of fibrotic progression or leukemic evolution, and secondarily control microvascular symptoms. Unlike other classic BCR::ABL1-negative myeloproliferative neoplasms, ET is frequently diagnosed in adolescents and young adults (AYA), defined as individuals aged 15 to 39 years, in up to 20% of patients. However, since the current risk stratification of this disease is based on models, including that of ELN, IPSET-Thrombosis and its revised version, mainly applied to an older patients' population, international guidelines are needed that specifically consider how to evaluate the prognosis of AYAs with ET. Furthermore, although ET is the most frequent MPN among AYA subjects, there is a lack of specific recommendations on how to treat it in this subgroup of patients, as management decisions are typically extrapolated from those for the elderly. Accordingly, since AYAs with ET represent a unique disease subset defined by attenuated genetic risk, more indolent phenotype, and longer survival than their older counterparts, treatment selection requires special attention to specific issues such as the risk of fibrotic/leukemic transformation, carcinogenicity, and fertility. This review article will provide a comprehensive overview of the diagnosis, prognostic stratification, and possible therapeutic approaches for AYA patients with ET, including antiplatelets/anticoagulants and cytoreductive agents, with a focus on pregnancy management in real-life clinical practice.

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.

Venous thromboembolism in viral diseases: A comprehensive literature review

Venous thromboembolism (VTE) is known to be a common respiratory and/or cardiovascular complication in hospitalized patients with viral infections. Numerous studies have proven human immunodeficiency virus infection to be a prothrombotic condition. An elevated VTE risk has been observed in critically ill H1N1 influenza patients. VTE risk is remarkably higher in patients infected with the Hepatitis C virus in contrast to uninfected subjects. The elevation of D-dimer levels supported the association between Chikungunya and the Zika virus and the rise of clinical VTE risk. Varicella-zoster virus is a risk factor for both cellulitis and the consequent invasive bacterial disease which may take part in thrombotic initiation. Eventually, hospitalized patients infected with the coronavirus disease of 2019 (COVID-19), the cause of the ongoing worldwide pandemic, could mainly suffer from an anomalous risk of coagulation activation with enhanced venous thrombosis events and poor quality clinical course. Although the risk of VTE in nonhospitalized COVID-19 patients is not known yet, there are a large number of guidelines and studies on thromboprophylaxis administration for COVID-19 cases. This study aims to take a detailed look at the effect of viral diseases on VTE, the epidemiology of VTE in viral diseases, and the diagnosis and treatment of VTE.

Rare, Overlooked, or Underappreciated Causes of Recurrent Abdominal Pain: A Primer for Gastroenterologists

Recurrent abdominal pain is a common reason for repeated visits to outpatient clinics and emergency departments, reflecting a substantial unmet need for timely and accurate diagnosis. A lack of awareness of some of the rarer causes of recurrent abdominal pain may impede diagnosis and delay effective management. This article identifies some of the key rare but diagnosable causes that are frequently missed by gastroenterologists and provides expert recommendations to support recognition, diagnosis, and management with the ultimate aim of improving patient outcomes.

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.

Combined Oral Contraceptives and Vascular Thrombosis: A Single-Center Experience

Background

Combined oral contraceptives (COCs) are frequently prescribed for contraception, to regulate ovulation and treat endometriosis, and to control menopausal symptoms. A major risk of hormonal contraceptives is vascular thrombosis.

Methods

A retrospective chart review of female patients with deep vein thrombosis (DVT), pulmonary embolism (PE), or other sites of thrombosis or emboli seen in the thrombosis clinic of the department of internal medicine at a tertiary care hospital in Saudi Arabia between March 2010 and February 2015 was performed to identify and characterize which women were taking COCs.

Results

Of 1,008 patients treated for DVT, PE, or other sites of thrombosis or emboli, 100 (9.9%) were taking COCs. Venous (98%) and arterial (2%) thromboses were seen. Overall, 62% of the patients experienced a DVT and 26% pulmonary emboli, and 20% of the patients experienced unusual sites of thrombosis. Furthermore, 53% were obese or morbidly obese. The incidence of venous thrombosis was the highest during the first year of COC use (73%). Of the patients, 8% had thrombophilia.

Conclusion

This study characterizes Saudi women with thrombotic events taking COCs and identifies risk factors, including unusual sites of thrombosis. Most patients experienced the vascular event during the first year of taking COCs. Age of 40-50 years, obesity, and thrombophilia were the commonly observed risk factors.

Therapeutic anticoagulation for splanchnic vein thrombosis in acute pancreatitis: A systematic review and meta-analysis

OBJECTIVES

The optimal management of patients with acute pancreatitis (AP) and splanchnic vein thrombosis (SVT) remains unknown. This systematic review and meta-analysis aimed to see if therapeutic anticoagulation (AC) improves outcomes in patients with AP and SVT.

METHODS

A systematic review was performed according to PRISMA guidelines. Main outcomes were recanalization, recurrent venous thromboembolism, development of varices, collaterals or cavernoma, haemorrhage and mortality. Meta-analysis were performed with the Mantel-Haenszel random effect models.

RESULTS

Seven retrospective cohort studies (3495 patients) were included. SVT occurred in 233 (7%) patients and involved most frequently the splenic vein (44%). Therapeutic AC was administered to 109 (47%) patients, most frequently to those with triple vessel thrombosis (72%) and least to those with isolated splenic vein (22%) or superior mesenteric vein thrombosis (0%). Most studies administered (low molecular weight) heparin followed by warfarin (duration ranged between 1.5 and 12 months). This meta-analysis showed an absolute risk difference of 9% (95% confidence interval [CI] = -11-28%) for recanalization, -3% (95% CI = -19-12%) for the development of varices, collaterals or cavernoma, 3% (95% CI = -6-12%) for haemorrhage and 2% (95% CI = -8-12%) for mortality.

CONCLUSIONS

Based on the currently available data, it remains unclear if therapeutic anticoagulation provides benefit to acute pancreatitis patients with splanchnic vein thrombosis. These results are based on low quality data underlining the need for further higher quality studies.

Tropical Fever Unveiling an Asymptomatic Case of Polycythemia Vera

We report a case of fulminant hepatic failure due to the Budd–Chiari syndrome following preservation with a tropical fever. A young lady came with fever, altered mental status, jaundice, and renal failure. Following tropical workup, it was diagnosed as a case of leptospirosis (WHO Faine's criteria) with multi-organ dysfunction. Despite adequate antimicrobial cover, she progressed to hepatic coma (hyperammonemia) and was noted to have worsening conjugated hyperbilirubinemia. Following history review and evaluation for other causes of hepatic failure, hepatic vein thrombosis was detected in addition to the presence of antibodies against Leptospira antigen. Further studies into the causes of thrombosis and persistent hemoconcentration despite aggressive fluid resuscitation led to the diagnosis of polycythemia vera (cytometric analysis). During her stay, she further worsened despite aggressive organ support including dialysis but she succumbed to gram-negative sepsis that occurred during her stay in ICU. This is an interesting and rare case of leptospirosis that unveiled a case of previously asymptomatic polycythemia vera.

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.

Idiopathic portal vein thrombosis not related to hepatic disease or malignancy

Acute portal vein thrombosis (PVT) is a rare disorder defined by the sudden occlusion of the portal vein, which could be partial or complete. Prothrombotic states, inherited or acquired, are thought to be the cause in patients without cirrhosis or malignancy. However, the aetiology of some cases remains idiopathic despite a multidisciplinary diagnostic approach. The initial diagnostic modality to confirm PVT is either contrast-enhanced abdominal (CT) or MRI; as it can identify predisposing factors, and detect evidence of complications. Eliciting the underlying aetiology is critical to guide overall management and prevent future recurrence. The purpose of treatment is to stop thrombus extension and achieve portal vein patency by anticoagulation to optimise outcomes. Herein, we present an unusual case of spontaneous PVT in a young woman. We will also discuss the evaluation of patients without obvious aetiology.

Anticoagulation and Vessel Recanalization in Cirrhotic Patients with Splanchnic Vein Thrombosis: A Multidisciplinary "Real Life" Experience

Background and Aim

Splanchnic vein thrombosis (SVT) is a potentially life-threatening complication of liver cirrhosis. This study aimed to evaluate the impact of a multi-disciplinary approach and early anticoagulation therapy (AT) on bleeding/thrombotic events, recanalization rates and outcome of cirrhotic patients with SVT.

Methods

This is a single-center, registry-based cohort study. Over 17 years, 149 SVT patients were enrolled and prospectively evaluated. Regarding cirrhotic-SVT, a pre-specified algorithm, guiding initial posology of AT and follow-up visits schedule, was performed. Major bleeding (MB), thrombotic events, functional liver scores and all cause-mortality were investigated. Efficacy of AT was evaluated by radiological imaging.

Results

In cirrhotic-SVT, the incidence rate of MB was 8.4 per 100 patient-year (95% CI, 3.83–15.97), while the incidence rate of thrombosis was 5.6 per 100 patient-year (95% CI, 2.05–12.2). In incidental SVT treated with AT, MB incidence was 6.5 per 100 patient-year (95% CI: 2.8–12.82), while in symptomatic SVT was 2.2 per 100 patient-year (95% CI: 0.25–8.02). All thrombotic recurrences occurred in incidental SVT (7.7 per 100 patient-years; 95% CI, 3.71–14.26). Overall survival was significantly higher in patients who had at least a partial recanalization (p < 0.01) and partial/total recanalization was independently associated with improved MELD score at multivariate analysis (HR 2.62, 95% CI 1.1–6.47, p = 0.03).

Conclusion

In cirrhotic SVT patients, partial or total resolution of thrombosis ameliorates liver function and is associated with higher overall survival. A multidisciplinary approach together with radiological follow-up at pre-fixed time improves patient selection and monitoring.

Increased levels of NETosis in myeloproliferative neoplasms are not linked to thrombotic events

Morbidity and mortality of Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) are mainly determined by thromboembolic complications. Thrombus formation is facilitated by a neutrophil-specific form of cell death linked to neutrophil extracellular trap (NET) formation (NETosis). Preclinical and clinical data suggested a potential link between NETosis and thrombosis in MPNs. In this study, we aimed to define the impact of NETosis on clinical end points in a large MPN cohort. NETosis was induced in vitro by ionomycin and quantified by enzyme-linked immunosorbent assay-based nucleosome release assays as well as fluorescent staining of free DNA in samples from 103 MPN patients and 28 healthy donors. NETosis rate was correlated with a broad set of clinical data, such as MPN subtype, mutational status, laboratory variables, history of thrombotic events, and treatment types. Triggered NETosis levels were clearly higher in MPN patients than in healthy donors. Positivity for JAK2 V617F or exon 12 as well as CALR mutations correlate with increased NET formation. However, neither JAK2 allelic burden nor history of thromboembolic complication nor the presence of other risk factors for thrombosis (eg, leukocytosis) were associated with the rate of NETosis. In addition, none of the analyzed laboratory parameters nor the type of treatment significantly impacted the rate of NETosis formation. The biology of MPNs has an impact on NET formation because genetic driver mutations favor induction of NETosis, but this does not seems to translate into important clinical end points such as thromboembolic complications. Therefore, NETosis may play a role in facilitating thrombosis, but it is not a sole causative determinant in MPN-associated thrombophilia.

Pregnancy outcomes in women with Budd-Chiari syndrome or portal vein thrombosis - a multicentre retrospective cohort study

Objective

To evaluate current practice and outcomes of pregnancy in women previously diagnosed with Budd–Chiari syndrome and/or portal vein thrombosis, with and without concomitant portal hypertension.

Design and setting

Multicentre retrospective cohort study between 2008 and 2021.

Population

Women who conceived in the predefined period after the diagnosis of Budd–Chiari syndrome and/or portal vein thrombosis.

Methods and main outcome measures

We collected data on diagnosis and clinical features. The primary outcomes were maternal mortality and live birth rate. Secondary outcomes included maternal, neonatal and obstetric complications.

Results

Forty‐five women (12 Budd–Chiari syndrome, 33 portal vein thrombosis; 76 pregnancies) were included. Underlying prothrombotic disorders were present in 23 of the 45 women (51%). Thirty‐eight women (84%) received low‐molecular‐weight heparin during pregnancy. Of 45 first pregnancies, 11 (24%) ended in pregnancy loss and 34 (76%) resulted in live birth of which 27 were at term (79% of live births and 60% of pregnancies). No maternal deaths were observed; one woman developed pulmonary embolism during pregnancy and two women (4%) had variceal bleeding requiring intervention.

Conclusions

The high number of term live births (79%) and lower than expected risk of pregnancy‐related maternal and neonatal morbidity in our cohort suggest that Budd–Chiari syndrome and/or portal vein thrombosis should not be considered as an absolute contraindication for pregnancy. Individualised, nuanced counselling and a multidisciplinary pregnancy surveillance approach are essential in this patient population.

Tweetable abstract

Budd–Chiari syndrome and/or portal vein thrombosis should not be considered as an absolute contraindication for pregnancy.

Budd–Chiari syndrome and/or portal vein thrombosis should not be considered as an absolute contraindication for pregnancy.

Linked article This article is commented on by YY Chung & MA Heneghan pp. 618 in this issue. To view this minicommentary visit https://doi.org/10.1111/1471-0528.17002.

The hemostatic and thrombotic complications of liver disease

Hepatic cirrhosis leads to numerous hematologic derangements resulting in a complex and tenuously rebalanced hemostatic milieu. The utility of common hematologic tests including the INR and aPTT in assessing hemostatic and thrombotic risk in patients with cirrhosis is limited, and consensus on transfusion thresholds and proper management of thrombotic complications continues to evolve. This review summarizes the pathophysiology of key derangements of hemostasis including those of platelets, von Willebrand factor, pro- and anticoagulation factors, and fibrin. Additionally, the pathogenesis, consequences, optimal management, and prevention of major thrombotic and bleeding complications in cirrhosis arte discussed.

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.

The efficacy and safety of direct oral anticoagulants in noncirrhotic portal vein thrombosis

Guidelines currently favor vitamin K antagonists or low-molecular-weight heparins for treatment of noncirrhotic portal vein thrombosis (ncPVT). Use of direct oral anticoagulants (DOACs) in PVT has been met with concern because of the lack of data. We conducted a retrospective study to investigate the efficacy and safety of DOACs for the treatment of ncPVT, and to compare them with standard therapies: 330 patients with ncPVT, followed-up for a mean 41.6 months, received warfarin (n = 108), enoxaparin (n = 70), rivaroxaban (n = 65), apixaban (n = 20), dabigatran (n = 8), fondaparinux (n = 2), or no anticoagulation (n = 57). The primary outcome was complete radiographic resolution (CRR) of PVT. Secondary outcomes included recanalization of occlusive PVT, cavernous transformation of the PV, development of chronic portal hypertensive symptoms (cPHS), and major bleeding. DOACs were associated with the highest CRR rates (dabigatran, 6/8 [75%]; apixaban, 13/20 [65%]; rivaroxaban, 42/65 [65%]). Enoxaparin was associated with a CRR rate similar to that of the DOACs (40/70 = 57%). Warfarin was associated with worse outcomes in this regard (CRR rate, 31% [33/108]; hazard ratio [HR] DOACs:warfarin, 2.91; 95% confidence interval [CI], 1.87-4.52; P < .0001). DOACs were associated with recanalization rates similar to enoxaparin and greater than warfarin (HR DOACs:warfarin, 3.45; 95% CI, 1.93-6.18; P < .0001). DOACs were associated with lower rates of cPHS, although this did not attain significance (DOACs, 8/93 [9%]; enoxaparin, 13/70 [19%]; warfarin, 31/108 [29%]). DOACs were associated with less major bleeding relative to warfarin (HR DOACs:warfarin, 0.20; 95% CI, 0.05-0.86; P = .0307). Patients harboring JAK2V617F, those with no evident predisposing factor for PVT, and those with occlusive thrombus demonstrated worse outcomes. DOACs appear effective and safe for the treatment of ncPVT.

Clinical characteristics and outcomes of splenic infarction in cancer patients: a retrospective, single center report of 206 cases

Cancer patients have a high risk of thromboembolic events including splenic infarct (SI). However, risk factors for SI in cancer patients are poorly understood, and the utility of systemic anticoagulation in such patients is uncertain. We performed a retrospective cohort study of all cancer patients with SI treated at Yale New Haven Hospital from 2008 to 2017. Central review of radiology imaging was performed to confirm the diagnosis of SI. Baseline differences in variables among patients with and without recurrent SI were compared using Fisher's exact test, Pearson's χ² test, and t-test. Multivariable regression models were conducted to identify factors associated with recurrent SI. Of 206 patients with cancer and SI, 42 had a prior venous thromboembolic event, while 29 had atrial fibrillation/flutter. At a median follow-up of 11.4 months (range: 0-142.3 months), 152 patients underwent follow-up imaging, with only 6 having recurrent SI. The use of anticoagulation after initial SI was associated with a nonsignificant increase in recurrent SI (p = 0.054) and was not associated with development of venous thromboembolism after SI (p = 0.414). In bivariate analyses, the risk of recurrent SI showed a significant association with lower platelet counts (p < 0.001) and with atrial fibrillation/flutter (p = 0.036). In a multivariable logistic regression model, no variables were identified that were associated with a higher risk of recurrent SI. SI in cancer patients is typically an isolated event with low recurrence risk. Anticoagulation use should be guided by other thromboembolic risk factors.

Anticoagulant Treatment for Splanchnic Vein Thrombosis in Liver Cirrhosis: A Systematic Review and Meta-Analysis

BACKGROUND

 Splanchnic vein thrombosis (SVT) is a common complication in patients with liver cirrhosis. The aim of this study was to evaluate the efficacy and safety of anticoagulant therapy for SVT in cirrhotic patients.

METHODS

 In this systematic review and meta-analysis, studies reporting on SVT recanalization and progression, recurrent venous thromboembolism (VTE), major bleeding, and overall mortality were searched in MEDLINE, EMBASE, and ClinicalTrial.gov up to December 2019. Pooled proportions and risk ratios (RRs) with corresponding 95% confidence intervals (CIs) were calculated.

RESULTS

 A total of 1,475 patients were included in 26 studies (23 observational and 3 randomized controlled trials). In patients receiving anticoagulant therapy, SVT recanalization occurred in 68% (95% CI, 62-74; 571/842 patients; 22 studies), SVT progression in 6% (95% CI, 4-9; 25/748 patients; 22 studies), recurrent VTE in 10% (95% CI, 4-22; 48/399 patients; 7 studies), major bleeding in 6% (95% CI, 4-10; 58/785 patients; 18 studies), and overall mortality in 9% (95% CI, 6-14; 68/787 patients; 17 studies). Anticoagulant treatment was associated with higher SVT recanalization (RR 3.19; 95% CI, 1.42-7.17), lower thrombosis progression (RR 0.28; 95% CI, 0.15-0.52), major bleeding (RR 0.52; 95% CI, 0.28-0.97), and overall mortality (RR 0.42; 95% CI, 0.24-0.73) compared with no treatment.

CONCLUSION

 Anticoagulant therapy seems to improve vein recanalization and to reduce SVT progression, major bleeding, and overall mortality in cirrhotic patients with SVT. The incidence of recurrent VTE during anticoagulation remains substantial.

The Natural History, Treatments, and Outcomes of Portal Vein Thrombosis in Patients With Inflammatory Bowel Disease

BACKGROUND

Portal vein thrombosis (PVT) is a poorly described complication of inflammatory bowel disease (IBD). We sought to better characterize presentations, compare treatments, and assess outcomes in IBD-related PVT.

METHODS

We conducted a retrospective investigation of IBD-related PVT at our institution. Multivariable Cox proportional hazards modeling was used to estimate adjusted hazard ratios across treatments.

RESULTS

Sixty-three patients with IBD-related PVT (26 with Crohn disease, 37 with ulcerative colitis) were followed for a median 21 months (interquartile ratio [IQR] = 9-52). Major risk factors included intra-abdominal surgery (60%), IBD flare (33%), and intra-abdominal infection (13%). Primary hematologic thrombophilias were rare and did not impact management. Presentations were generally nonspecific, and diagnosis was incidental. Ninety-two percent of patients (58/63) received anticoagulation (AC), including 23 who received direct oral anticoagulants (DOACs), 22 who received warfarin, and 13 who received enoxaparin. All anticoagulated patients started AC within 3 days of diagnosis. Complete radiographic resolution (CRR) of PVT occurred in 71% of patients. We found that DOACs were associated with higher CRR rates (22/23; 96%) relative to warfarin (12/22; 55%): the hazard ratio of DOACs to warfarin was 4.04 (1.83-8.93; P = 0.0006)). Patients receiving DOACs required shorter courses of AC (median 3.9 months; IQR = 2.7-6.1) than those receiving warfarin (median 8.5 months; IQR = 3.9-NA; P = 0.0190). Incidence of gut ischemia (n = 3), symptomatic portal hypertension (n = 3), major bleeding (n = 4), and death (n = 2) were rare, and no patients receiving DOACs experienced these adverse outcomes.

CONCLUSIONS

We show that early and aggressive use of AC can lead to excellent outcomes in IBD-associated PVT and that DOACs are associated with particularly favorable outcomes in this setting.

Outcomes of long-term anticoagulant treatment for the secondary prophylaxis of splanchnic venous thrombosis

BACKGROUND

Splanchnic vein thrombosis (SVT) is an uncommon but potentially life-threatening disease usually related to different underlying clinical conditions. The risk of SVT recurrences is high over time in patients with an underlying permanent prothrombotic condition. Vitamin K antagonists (VKA) represent the mainstay of treatment for SVT. Data about the efficacy and safety of direct oral anticoagulants (DOACs) are reported in the literature for the treatment of acute SVT, but less is known about their application for the secondary prophylaxis of venous thromboembolism (VTE). The aim of this study was to assess the efficacy and safety of long-term DOACs therapy in patients at high-risk of thrombosis, compared to VKA.

METHODS

This is a retrospective single-centre study including 70 patients with SVT on long-term anticoagulant treatment with VKA followed-up at our Units between January 2017 and December 2019. All the patients were at high thrombotic risk defined as the presence of a permanent prothrombotic condition requiring long-term anticoagulation. During follow-up, 28 patients were shifted to DOACs and their clinical outcomes were compared to those of the patients who continued VKA therapy. All the arterial and venous thrombotic events of the splanchnic and extra-splanchnic districts as well as the haemorrhagic adverse events occurring during follow-up were recorded.

RESULTS

Of the seventy patients enrolled in the study, 36 patients (51.4%) had a single-segment involvement thrombosis (28.5% of portal vein, 7.1% of superior mesenteric vein, 4.3% of splenic vein, 11.5% of hepatic veins) and 34 patients (48.6%) had multi-segment involvement at the time of diagnosis. 42 patients (60%) continued VKA therapy and 28 (40%) were switched to DOACs. Median follow-up was 6 years (range 2-8) during VKA and 1.9 years (range 1-5.2) during DOACs. The incidence of thrombotic events was similar between patients on VKA and those on DOACs. Patients on VKA developed deep vein thrombosis (DVT), and of the patients on DOACs 1 developed NSTEMI and 1 DVT. No major haemorrhagic events occurred. Minor bleedings occurred in 26% of patients on VKA and in none of the DOACs patients (P: 0.09).

CONCLUSIONS

Our results highlight that DOACs could represent an effective and safe alternative to the VKA for secondary prophylaxis in SVT patients at high risk of thrombosis.

Prescribing patterns and outcomes of venous thromboembolism prophylaxis in hospitalized medical and cancer patients: Observations from the Ottawa Hospital

Guidelines suggest broad use of pharmacologic prophylaxis to prevent venous thromboembolism (VTE) in hospitalized medical patients, however little 'real-world' data exists to support this. Our goal was to describe the use of thromboprophylaxis among general medical and cancer patients admitted to hospital, compare VTE and bleeding outcomes according to use of thromboprophylaxis, and to determine what variables influence prescribing patterns and outcomes. Patients admitted to the general medical and oncology services at The Ottawa Hospital between 2010 and 2015 were retrospectively reviewed and classified according to whether they received initial, delayed, or no pharmacologic thromboprophylaxis during their first hospitalization. Patients with an alternate indication for anticoagulation or those admitted with a bleeding event were excluded from analysis. The primary efficacy outcome was any symptomatic VTE during index hospitalization or within 90 days of discharge, and the primary safety outcome was clinically relevant bleeding during the index hospitalization. 17,262 patients were included in our final analysis. General medical patients selected to receive no, initial, or delayed thromboprophylaxis had 0.4%, 0.7%, and 2.4% rates of VTE; and 0.2%, 0.7%, and 1.5% rates of clinically relevant bleeding complications, respectively. Cancer patients had significantly higher rates of VTE: 3.3%, 3.9%, and 5.0%; and 0.9%, 0.7%, and 3.0% rates of clinically relevant bleeding among those selected to receive no, initial, or delayed thromboprophylaxis, respectively. Overall, our study suggests that broad use of pharmacologic thromboprophylaxis may be unnecessary in select low-risk general medical patients and may be less effective in cancer patients in whom new studies are indicated.

Venous thrombosis of the liver: current and emerging concepts in management

Venous thrombosis within the hepatic vasculature is associated with a distinct array of risk factors, characteristics, and potential complication. As such, it entails unique management considerations and strategies relative to the more common categories of venous thromboembolic disease. Although broadly divided into thrombosis of the afferent vasculature (the portal venous system) and efferent vasculature (the hepatic venous system), presentations and management strategies within these groupings are heterogeneous. Management decisions are influenced by a variety of factors including the chronicity, extent, and etiology of thrombosis. In this review we examine both portal vein thrombosis and hepatic vein thrombosis (and the associated Budd-Chiari Syndrome). We consider those factors which most impact presentation and most influence treatment. In so doing, we see how the particulars of specific cases introduce nuance into clinical decisions. At the same time we attempt to organize our understanding of such cases to help facilitate a more systematic approach. Critically, we must recognize that although increasing evidence is emerging to help guide our management strategies, the available data remain limited and largely retrospective. Indeed, current paradigms are based largely on observational experiences and expert consensus. As new and more rigorous studies emerge, treatment strategies are likely to be continually refined, and paradigm shifts are sure to occur.

Anticoagulant therapy in the treatment of splanchnic vein thrombosis associated to acute pancreatitis: a 3-year single-centre experience

Splanchnic vein thrombosis (SVT) is a possible complication of acute pancreatitis (AP). There are no precise guidelines on the use of anticoagulant therapy (AT) in these patients. The aim of the study was to determine the safety and the efficacy of AT in AP-associated SVT. Two hundred twenty-one patients were retrospectively and consecutively enrolled from the Pancreatic Outpatient Clinic of the "A. Gemelli" hospital. Patients had a diagnosis of AP and a diagnostic imaging to evaluate whether they had or not SVT. Twenty-seven out of 221 AP patients had SVT (12.21%) and AT therapy was administered to 16 patients (59.3%), for 5.2 ± 2.2 months. A therapeutic dose of low molecular weight heparin was administered (100 UI/kg b.i.d.) at the diagnosis, with fondaparinux 7.5 mg/day, or vitamin K antagonist, or the novel direct oral anti-coagulants, upon discharge. The presence of SVT resulted significantly associated to male sex (p = 0.002). The recanalization rates were 11/16 (68.7%) in patients who received AT, and 3/11 (27.3%) in patients who did not receive it. There was a significant difference between the recanalization rates with and without AT (p = 0.03, OR 5.87). No SVT recurrence was registered during follow-up. No treated patient developed haemorrhagic complications after AT. No deaths were recorded, either in the group undergoing AT or in the one that was not. In conclusion, AT in AP-associated SVT appears to be safe and effective; yet prospective clinical trials are needed to confirm our results.

Splanchnic Vein Thrombosis: Current Perspectives

Splanchnic vein thrombosis (SVT) including portal, mesenteric, splenic vein thrombosis and the Budd-Chiari syndrome, is a manifestation of unusual site venous thromboembolism. SVT presents with a lower incidence than deep vein thrombosis of the lower limbs and pulmonary embolism, with portal vein thrombosis and Budd-Chiari syndrome being respectively the most and the least common presentations of SVT. SVT is classified as provoked if secondary to a local or systemic risk factor, or unprovoked if the causative trigger cannot be identified. Diagnostic evaluation is often affected by the lack of specificity of clinical manifestations: the presence of one or more risk factors in a patient with a high clinical suspicion may suggest the execution of diagnostic tests. Doppler ultrasonography represents the first line diagnostic tool because of its accuracy and wide availability. Further investigations, such as computed tomography and magnetic resonance angiography, should be executed in case of suspected thrombosis of the mesenteric veins, suspicion of SVT-related complications, or to complete information after Doppler ultrasonography. Once SVT diagnosis is established, a careful patient evaluation should be performed in order to assess the risks and benefits of the anticoagulant therapy and to drive the optimal treatment intensity. Due to the low quality and large heterogeneity of published data, guidance documents and expert opinion could direct therapeutic decision, suggesting which patients to treat, which anticoagulant to use and the duration of treatment.

Update on Management of Portal Vein Thrombosis and the Role of Novel Anticoagulants

The clinical management of portal vein thrombosis (PVT) remains ambiguous due to its heterogeneous presentations and its associations with liver disease, malignancy, and hypercoagulable states. The natural history and clinical outcome of PVT are highly variable, dependent upon size, extent and degree of the thrombotic occlusion, as well as the physiological impact of patient comorbidities. While existing clinical guidelines consistently recommend low molecular weight heparin or vitamin K antagonist anticoagulation in cirrhotic patients with symptomatic acute PVT, management of asymptomatic and chronic PVT may need to be determined on a case-by-case basis, factoring in the state of underlying liver disease. In general, patients with PVT and underlying malignancy should be anticoagulated to alleviate symptoms and prevent recurrences that could disrupt the cancer management. However, existing clinical data does not support routine anticoagulation of cirrhotic patients with asymptomatic PVT in the absence of underlying cancer. While low molecular weight heparin and vitamin K antagonist remain the most commonly used agents in PVT, an emerging body of clinical evidence now suggests that direct-acting oral anticoagulants may be used safely and effectively in PVT. As such, direct-acting oral anticoagulants may offer a more convenient anticoagulation alternative for PVT management in future practice.

Treatment of Iron Deficiency in the Elderly: A New Paradigm

Although gene sequencing has elucidated several mutations associated with mild cytopenias in older individuals, iron deficiency remains the most common cause of anemia. Oral iron has remained the frontline standard despite evidence that it is poorly tolerated, often ineffective, and frequently harmful. Studies of different formulations of intravenous iron have shown it effective, with marginal to no toxicity. Serious adverse events have not been described and the failure to address its administration in iron-deficient elderly patients is an unmet clinical need. This article outlines situations in which oral iron should be proscribed and offers an approach to administration of available formulations.

Venous thrombosis in unusual sites: A practical review for the hematologist

Thrombosis of unusual venous sites encompasses a large part of consultative hematology and is encountered routinely by practicing hematologists. Contrary to the more commonly encountered lower extremity venous thrombosis and common cardiovascular disorders, the various thromboses outlined in this review have unique presentations, pathophysiology, workup, and treatments that all hematologists should be aware of. This review attempts to outline the most up to date literature on cerebral, retinal, upper extremity, hepatic, portal, splenic, mesenteric, and renal vein thrombosis, focusing on the incidence, pathophysiology, provoking factors, and current recommended treatments for each type of unusual thrombosis to provide a useful and practical review for the hematologist.

Splanchnic vein thrombosis in myeloproliferative neoplasms: treatment algorithm 2018

Myeloproliferative neoplasms (MPNs) are a leading cause of splanchnic vein thrombosis (SVT). SVT is observed in all MPNs and frequently affects young patients. Therapy should be addressed to three main goals: preventing thrombosis recurrence, managing the underlying MPN, and supporting liver dysfunction. Life-long oral anticoagulation with vitamin K antagonists is the cornerstone of the antithrombotic treatment. However, recurrences of SVT or other thrombosis may occur in 15-20% of patients. Direct oral anticoagulants can represent an alternative and preliminary data encourage comparative studies. Survival of patients with SVT in MPN is primarily influenced by the natural history of the underlying neoplasms, rather than the SVT event. An aggressive management is recommended and a treatment algorithm based on the different MPN subtypes is proposed. Hydroxyurea is the cytoreductive drug of choice in polycythemia vera and essential thrombocythemia, whereas ruxolitinib is indicated in intermediate and high-risk patients with myelofibrosis and in PV patients resistant or intolerant to hydroxyurea. The management of SVT in MPNs requires a multidisciplinary approach that may include a hematologist, a gastroenterologist, an interventional radiologist, and a surgeon. In the case of clinical deterioration despite pharmacological therapy, patients with SVT should be considered for invasive procedures or liver transplantation.

Visceral Thromboses in Pancreas Adenocarcinoma: Systematic Review

Within gastrointestinal malignancies, primary hepatocellular carcinoma and pancreatic ductal adenocarcinoma (PDAC) are frequently associated with visceral thromboses (VT). Thrombus formation in the portal (PVT), mesenteric (MVT), or splenic vein (SVT) system leads to portal hypertension and intestinal ischemia. VT in PDAC may convey a risk of increased distal thrombosis and poses therapeutic uncertainty regarding the role of anticoagulation. An increasing number of reports describe VT associated with PDAC. It is possible that early diagnosis of these events may help reduce morbidity and speculatively improve oncologic outcomes. To perform a systematic review to study PVT, MVT, and SVT associated with PDAC, and to provide a comprehensive review. Medline/PubMed, Embase, Web of Science, Scopus, and the Cochrane Library. Data Extraction and Assessment: Two blinded independent observers extracted and assessed the studies for diagnosis of PVT, MVT, and SVT in PDAC. Studies were restricted to English-language literature published between 2007 and 2016. Eleven articles were identified. Five case reports and 7 retrospective studies were found, with a total of 127 patients meeting the inclusion criteria. The mean age at diagnosis was 64 years. PVT was found in 35% (n = 46), SVT in 52% (n = 65), and MVT in 13% (n = 15). Mean follow-up time was 26 months. Only 3 of the selected articles studied the impact of anticoagulation in VT. All patients with nonvisceral thrombosis (eg, deep-vein thrombosis, pulmonary emboli) were therapeutically treated; in contrast, patients with VT only rarely received treatment. VT in PDAC is a frequent finding at diagnosis or during disease progression. Evidence to guide treatment choices is limited, and current management is based on inferred experience from nononcologic settings. Anticoagulation appears to be safe in VT, with most of the large studies recommending a careful assessment for patients at a high risk of bleeding.

Evaluation of direct oral anticoagulants and vitamin K antagonists in mesenteric venous thrombosis

BACKGROUND/AIM

Mesenteric venous thrombosis is a rare lethal disease. The main aim of the present study was to evaluate clinical efficacy and safety of direct oral anticoagulants and vitamin K antagonists in mesenteric venous thrombosis patients.

METHODS

Retrospective study of 102 mesenteric venous thrombosis patients treated between 2004 and 2017 at a center with a conservative medical first approach. Median clinical follow-up was 4 years.

RESULTS

Computed tomography showed successful recanalization of thrombosis in 71% of patients on vitamin K antagonists and 69% of patients on direct oral anticoagulants ( p = 0.88). Overall major and esophageal variceal bleeding rate was 14.7% and 2.9%, respectively. No difference in major bleeding ( p = 0.54) was found between vitamin K antagonists and direct oral anticoagulants. No mesenteric venous thrombosis recurrence occurred during follow-up, and one venous thromboembolism occurred after cessation of anticoagulation.

CONCLUSION

Anticoagulation with direct oral anticoagulants and vitamin K antagonists was efficient in patients with mesenteric venous thrombosis. Bleeding complications was a concern during treatment in both groups.

Approach to thrombosis at unusual sites: Splanchnic and cerebral vein thrombosis

Splanchnic vein thrombosis (SVT) and cerebral vein thrombosis (CVT) are two manifestations of unusual site venous thromboembolism (VTE). SVT includes thrombosis in the portal, mesenteric or splenic veins, and the Budd-Chiari syndrome. CVT encompasses thrombosis of the dural venous sinuses and thrombosis of the cerebral veins. Unusual site VTE often represents a diagnostic and therapeutic challenge because of the heterogeneity in clinical presentation, the limited evidence available in the literature on the acute and long-term prognosis of these diseases, and the lack of large randomized controlled trials evaluating different treatment options. This narrative review describes the approach to patients with SVT or CVT by examining the diagnostic process, the assessment of potential risk factors and the appropriate anticoagulant treatment.

Incidental venous thromboembolism: is anticoagulation indicated?

Patients with cancer have a high risk of venous thromboembolism (VTE) and about one-half of these events are incidentally detected. The prognosis of incidental VTE appears to be similar to symptomatic events, with comparably high rates of recurrent VTE in this patient population. In the absence of major contraindications, anticoagulant treatment with low-molecular-weight heparin for 3 to 6 months is generally recommended for incidental proximal deep vein thrombosis as well as for incidental pulmonary embolism that involves multiple subsegmental or more proximal pulmonary arteries. The decision of whether to extend treatment beyond 3 to 6 months should be evaluated on a case-by-case basis after periodic reassessment of the risks factors for bleeding and recurrent VTE while also taking into account patient preferences. The clinical relevance of a single incidental subsegmental pulmonary embolism without concomitant deep vein thrombosis is uncertain and either a watchful approach or a shorter course of anticoagulation to minimize the bleeding risk may also be considered. Preliminary evidence suggests that anticoagulation treatment may be beneficial for cancer patients with incidental distal deep vein thrombosis or incidental splanchnic vein thrombosis.

Clinical manifestations and imaging tools in the diagnosis of splanchnic and cerebral vein thromboses

Splanchnic vein thrombosis (SVT) and cerebral vein thrombosis (CVT) are uncommon manifestation of venous thromboembolism (VTE), occurring less frequently than deep vein thrombosis of the lower extremities and pulmonary embolism. SVT encompasses portal vein thrombosis, mesenteric vein thrombosis, splenic vein thrombosis and the Budd-Chiari syndrome. It is therefore a heterogeneous disease, with differences in clinical manifestations according to the site of thrombosis. CVT includes thrombosis of the cortical or deep cerebral veins and thrombosis of the major dural venous sinuses. Clinical presentation is variable, with a wide spectrum of signs and symptoms that can mimic other cerebral diseases. There are no clinical algorithms or specific laboratory tests that can guide in the identification of SVT and CVT; therefore, the diagnosis relies exclusively on imaging tests. Conventional angiography once was the gold standard for the diagnosis of SVT and CVT, but it is rarely used nowadays. Abdominal ultrasound (US), computed tomography (CT) and magnetic resonance (MR) with angiography are currently used for the diagnosis of SVT; while cerebral CT and MR with angiography are currently used for the diagnosis of CVT. These imaging tests have different sensitivities/specificities and different advantages/disadvantages that should be kept into consideration when choosing the appropriate imaging test based on the suspected site of thrombosis. This narrative review summarizes the clinical and diagnostic approach to SVT and CVT.

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.

Incidence rates and case fatality rates of portal vein thrombosis and Budd-Chiari Syndrome

Little information is available on the incidence of splanchnic vein thrombosis and on mortality rates during the acute phase of the disease. We performed a large epidemiologic study on hospital admissions for portal vein thrombosis (PVT) and the Budd-Chiari syndrome (BCS) between 2002 and 2012 in Northwestern Italy. Primary and secondary discharge diagnoses of PVT and BCS were identified using the 9th edition International Classification of Diseases codes 453.0, 572.1 and 452. Hospitalisations for recurrent events were not included. Information was collected on age and gender, vital status at discharge, duration of hospitalisation, and up to five secondary discharge diagnoses. Comorbidity was evaluated using the Charlson comorbidity index (CCI). A total of 3535 patients with PVT and 287 with BCS were hospitalized. The overall gender-specific incidence rates for PVT were 3.78 per 100,000 inhabitants in males and 1.73 per 100,000 inhabitants in females; for BCS 2.0 and 2.2 per million inhabitants, respectively. In-hospital case fatality was 7.3 % in patients with PVT and 4.9 % in patients with BCS. Age, non-abdominal solid cancer, and CCI were independently associated with in-hospital mortality in both PVT and BCS after stepwise regression analysis, male gender and haematologic cancer were associated with mortality in BCS patients only. In this large study we confirmed the low incidence of BCS and we found an incidence of PVT higher than previously reported. This incidence was stable during the period of observation. In-hospital mortality is not negligible, in particular in PVT patients.

Current and future perspectives in imaging of venous thromboembolism

Several thrombus imaging techniques for the diagnosis of venous thromboembolism (VTE) are available. The most prevalent forms of VTE are deep vein thrombosis of the lower extremities and pulmonary embolism. However, VTE may also occur at unusual sites such as deep veins of the upper extremity and the splanchnic and cerebral veins. Currently, the imaging techniques most widely used in clinical practice are compression ultrasonography and computed tomography (CT) pulmonary angiography. Moreover, single-photon emission CT, CT venography, positron emission tomography, and different magnetic resonance imaging (MRI) techniques, including magnetic resonance direct thrombus imaging, have been evaluated in clinical studies. This review provides an overview of the technique, diagnostic accuracy and potential pitfalls of these established and emerging imaging modalities for the different sites of venous thromboembolism.