Recent portal vein thrombosis in adults: Clinical features, diagnosis, and management

INTRODUCTION — 

The portal vein is formed by the confluence of the splenic and superior mesenteric veins, which drain the spleen and small intestine, respectively (figure 1). Occlusion of the portal vein by thrombus (ie, portal vein thrombosis [PVT]) typically occurs in patients with cirrhosis and/or thrombotic disorders (table 1), although PVT may also develop in patients without an underlying condition.

PVT is classified as follows (table 2):

●Recent PVT – Recent PVT refers to PVT that developed less than six months ago. Patients with recent PVT have not yet developed features of chronic PVT, such as collateral circulation (eg, cavernous portal transformation) or portal hypertension.

●Chronic PVT – Chronic PVT refers to PVT that persists for more than six months.

The occlusion of the vein may be partial or complete, and the clot may be limited to the portal vein or may extend into the mesenteric veins or the splenic vein.

This topic will discuss the clinical features, diagnosis, and management of recent PVT. The discussion that follows is largely consistent with society guidelines [1-4].

Other issues related to PVT, including risk factors, are discussed in detail separately:

●Chronic PVT – (See "Chronic portal vein thrombosis in adults: Clinical features, diagnosis, and management".)

●Hemostatic abnormalities in patients with liver disease – (See "Hemostatic abnormalities in patients with liver disease".)

Management of mesenteric venous thrombosis is discussed separately. (See "Mesenteric venous thrombosis in adults".)

CLINICAL FEATURES

Patterns of clinical presentation — The clinical features of recent portal vein thrombosis (PVT) vary with the extent and timing of the venous occlusion. Thus, the presentation of recent PVT ranges from asymptomatic patients to those with considerable abdominal pain that develops suddenly or progresses over a few days [5]. Abdominal pain may be accompanied by fever (temperature ≥38°C [100.4°F]), dyspepsia, and/or symptoms related to intestinal ischemia (eg, abdominal distension). Patients typically do not have abdominal guarding unless PVT is the result of an intra-abdominal inflammatory process or if intestinal infarction has occurred. (See "Overview of intestinal ischemia in adults", section on 'Clinical features'.)

Symptoms may be more severe when thrombosis results in restricted blood flow and venous congestion affecting small bowel venous drainage. This presentation is more common in patients without cirrhosis or in patients with thrombosis of the proximal mesenteric vein resulting in intestinal ischemia. In such patients, abdominal pain may radiate to the back, persist beyond five days, be associated with abdominal distension from ascites, or be associated with bloody diarrhea [5]. In contrast, intestinal ischemia with severe abdominal pain is rare in patients with cirrhosis and portal hypertension because they often have a portosystemic collateral circulation that prevents severe vascular congestion [1].

Fever, chills, and tender hepatomegaly suggest septic PVT (also referred to as pylephlebitis). (See "Pylephlebitis", section on 'Clinical manifestations'.)

Patients may also have symptoms related to the underlying condition that predisposes them to the developing PVT, such as inflammatory bowel disease or acute pancreatitis. For some patients with underlying inflammatory bowel disease, the clinical presentation of recent PVT (eg, abdominal pain, diarrhea) may mimic a disease flare. (See "Chronic portal vein thrombosis in adults: Clinical features, diagnosis, and management", section on 'Epidemiology and risk factors'.)  

Patients with cirrhosis may present with signs of liver decompensation (eg, new onset ascites, variceal bleeding).

Asymptomatic patients may be identified when they undergo abdominal imaging for other reasons (eg, surveillance for hepatocellular carcinoma). (See "Surveillance for hepatocellular carcinoma in adults".)

Laboratory features — Laboratory studies in patients with recent PVT may include [3]:

●Elevated levels of acute phase reactants (eg, C-reactive protein).

●Normal or transiently elevated aminotransferases (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]). Liver enzymes are usually normal because hepatic arterial blood flow compensates for decreased portal inflow, although liver enzymes may be moderately elevated (<5 times the upper limit of normal) for a few days in some patients.

●For patients with bowel ischemia, findings may include a marked leukocytosis with a predominance of immature white blood cells, an elevated hematocrit consistent with hemoconcentration, and a metabolic acidosis. (See "Overview of intestinal ischemia in adults", section on 'Clinical features'.)

●For patients with septic PVT from an acute intra-abdominal process, bacteremia may be polymicrobial. (See "Pylephlebitis".)

●For patients with cirrhosis, laboratory testing may reveal an elevated bilirubin, low platelet count, prolonged international normalized ratio (INR), and/or kidney insufficiency. (See "Cirrhosis in adults: Etiologies, clinical manifestations, and diagnosis", section on 'Laboratory findings'.)

DIAGNOSTIC EVALUATION

When to suspect recent PVT — Recent PVT may be suspected in the following groups:

●Patients with cirrhosis who develop the acute onset of abdominal pain with or without signs of liver decompensation (eg, new onset ascites, variceal bleeding) [6].

●Patients with a thrombotic condition (eg, Factor V Leiden, antiphospholipid syndrome) who develop the acute onset of abdominal pain.

●Patients with persistent, unexplained abdominal pain

Selecting an imaging method

Symptomatic patients with risk factors — For symptomatic patients with an underlying risk factor for PVT (eg, cirrhosis, thrombotic disorder), we typically obtain multiphase abdominal computed tomography (CT) with intravenous contrast to establish the diagnosis, to evaluate for associated conditions (eg, intra-abdominal infection), to evaluate for signs of intestinal ischemia/infarction, to assess the severity and extent of the thrombus, and to assess for small vessels near the portal vein (ie, also referred to as collaterals or cavernous transformation) (table 1) [1,7]. (See 'Post-diagnosis evaluation' below.)

On CT scan with intravenous contrast, features of recent PVT include lack of luminal enhancement in the portal vein, increased liver enhancement in the arterial phase, and decreased liver enhancement in the portal phase (image 1) [1,8].

An alternative to CT scan is multiphase abdominal magnetic resonance imaging (MRI) with intravenous contrast. On MRI, PVT appears as a filling defect that partially or completely occludes the vessel lumen in the portal venous phase [9]. MRI avoids radiation and has comparable diagnostic accuracy to CT scan, although data are limited. In a study of 36 patients with portal hypertension who underwent contrast-enhanced MRI to evaluate for PVT, the sensitivity and specificity were 100 percent and 99 percent, respectively [10].

If CT and MRI not available, ultrasound with Doppler study is an alternative, although ultrasound may not detect predisposing conditions or intestinal ischemia.

Symptomatic patients without risk factors — For patients with symptoms but without known risk factors (eg, no history of cirrhosis or thrombotic disorder), we initiate testing with abdominal ultrasound with Doppler. On ultrasound, a recent thrombus appears as hypo- or iso-echoic material within the lumen of a mildly dilated portal vein [7]. The Doppler study estimates the flow rate and detects shunts (ie, multiple small vessels in the area around the portal vein) [11].

If the ultrasound suggests recent PVT, we obtain multiphase abdominal CT scan with intravenous contrast to establish the diagnosis of PVT [8]. (See 'Symptomatic patients with risk factors' above.)

Ultrasonography with Doppler imaging has an estimated sensitivity of 89 percent and a specificity of 92 percent for diagnosing PVT [12].

Asymptomatic patients — If PVT is found incidentally by abdominal ultrasound or other nonadvanced imaging study, we obtain multiphase abdominal CT scan with intravenous contrast to establish the diagnosis. Asymptomatic patients are typically those with cirrhosis who had surveillance imaging for hepatocellular carcinoma. (See 'Symptomatic patients with risk factors' above.)

Establishing the diagnosis — The diagnosis of recent PVT is established with abdominal imaging that demonstrates portal venous occlusion in the absence of venous channels within or around the thrombosed portal vein (referred to as cavernous portal transformation). (See 'Selecting an imaging method' above.)

POST-DIAGNOSIS EVALUATION

Determine the severity of thrombosis — We use multiphase, contrast-enhanced cross-sectional imaging with CT or MRI to assess severity of thrombosis (partially occlusive or complete main trunk PVT) and for signs of intestinal ischemia (eg, bowel wall thickening, intestinal pneumatosis with portal vein gas, bowel dilation). The clinical manifestations and diagnosis of intestinal ischemia are discussed in detail separately. (See "Overview of intestinal ischemia in adults".)

Patients with intestinal ischemia require multidisciplinary care including clinicians with surgical, critical care, and radiology expertise.

Assess for predisposing conditions — We evaluate patients without cirrhosis or other known risk factors for predisposing conditions such as an acute inflammatory condition (eg, diverticulitis) or thrombotic disorder (eg, Factor V Leiden, antiphospholipid syndrome) (table 1). (See "Pylephlebitis".)

The evaluation of patients with PVT or other venous thrombosis (eg, deep vein thrombosis of the lower extremity) for hypercoagulable conditions is discussed in detail separately. (See "Evaluating adult patients with established venous thromboembolism for acquired and inherited risk factors".)

Because PVT is common in patients with cirrhosis, we typically do not evaluate them for an underlying thrombotic disorder unless they have a history of thrombosis at another site [13].

Assess for underlying malignancy — We assess all patients for malignancy-related PVT that may manifest as tumor directly invading the portal vein (eg, hepatocellular carcinoma) or as a tumor externally constricting the portal vein (eg, pancreatic cancer, cholangiocarcinoma) [5]. In such patients, a thrombus within the portal vein may develop as a secondary event.

We review cross-sectional imaging for any of the following characteristics that suggest a malignant PVT [14-16] (see 'Selecting an imaging method' above):

●Abdominal or liver mass adjacent to the thrombus

●Disruption of the vessel walls or tumor encroaching on the portal vein

●Portal vein diameter >23 mm

●Enhancement of endoluminal material during the arterial phase of contrast injection

●On Doppler ultrasound, arterial-like pulsatile flow

In addition, an elevated alpha fetoprotein (usually >1000 ng/dL) suggests hepatocellular carcinoma.

The clinical features and diagnosis of abdominal malignancies that have been associated with recent PVT are discussed separately:

●Hepatocellular carcinoma – (See "Clinical features and diagnosis of hepatocellular carcinoma".)

●Pancreatic cancer – (See "Clinical manifestations, diagnosis, and staging of exocrine pancreatic cancer".)

●Cholangiocarcinoma - (See "Clinical manifestations and diagnosis of cholangiocarcinoma".)

MANAGEMENT

General measures — General measures for patients with PVT include:

●Manage the underlying condition (if present) – If an underlying inflammatory or thrombotic condition is identified (table 1), we initiate therapy for the underlying condition. As an example, patients with an intra-abdominal infection (eg, diverticulitis, cholecystitis) receive antimicrobial therapy. (See "Pylephlebitis", section on 'Treatment' and "Antimicrobial approach to intra-abdominal infections in adults".)

The management of patients with an underlying myeloproliferative disorder (eg, polycythemia vera, essential thrombocythemia) is discussed separately. (See "Polycythemia vera and secondary polycythemia: Treatment and prognosis" and "Essential thrombocythemia: Treatment and prognosis".)

●Specialist referral – We suggest that patients with PVT are referred to a center with specialty services including hepatology, hematology, and interventional radiology.

Assess bleeding risk — We evaluate the patient’s bleeding risk prior to initiating therapy for PVT. This assessment is similar to evaluating patients who have venous thrombosis at other sites (eg, deep venous thrombosis), and these issues are discussed separately. (See "Overview of the treatment of lower extremity deep vein thrombosis (DVT)".)

For patients with cirrhosis, the pretreatment evaluation also includes upper endoscopy to screen for high-risk esophageal varices. (See 'Patients with cirrhosis' below.)

Selecting an initial approach

Patients without cirrhosis — Anticoagulation is first line therapy for patients with recent PVT who do not have cirrhosis or a contraindication to anticoagulation (eg, active bleeding, excessive bleeding risk). (See 'Assess bleeding risk' above.)

The goal of anticoagulation is to restore patency of thrombosed veins (also referred to as recanalization) and to prevent the following [4] (see 'Anticoagulation' below):

●Extension of clot to mesenteric and splenic veins

●Congestive intestinal ischemia

●Development of chronic PVT that may be complicated by portal hypertension

For most patients, symptoms (eg, abdominal pain) begin to improve within hours to days after initiating anticoagulation. For patients who do not respond to anticoagulation and who have persistent symptoms and/or signs of progressive disease (eg, intestinal ischemia), pharmacologic and/or endovascular thrombolysis may be an option. (See 'Subsequent therapy' below.)

The use of anticoagulation has been supported by studies suggesting that anticoagulation was associated with rates of partial recanalization of the portal vein ranging from 63 to 93 percent, and with complete recanalization rates ranging from 34 to 45 percent [17-19]. As an example, in a study of 95 patients with recent PVT in the absence of cirrhosis, anticoagulation was associated with achieving complete portal vein patency in 39 percent of patients after a median of nearly eight months [17]. Patients with ascites or an occluded splenic vein were at higher risk for failure to recanalize the portal vein. Recanalization is important because restoring venous drainage of the small intestine eliminates the risk of intestinal ischemia, intestinal infarction, and complications related to chronic PVT (eg, portal hypertension). (See 'Prognosis' below.)

The use of anticoagulation for recent PVT is also indirectly supported by trials that show benefits of anticoagulation in patients with deep vein thrombosis. (See "Overview of the treatment of lower extremity deep vein thrombosis (DVT)".)

For patients with recent PVT who do not have cirrhosis, studies have reported generally low rates of bleeding related to anticoagulation that range from 0 to 6 percent (often minor bleeding, but sometimes severe) [18-21].

Patients with cirrhosis — The decision to use anticoagulation in patients with cirrhosis is individualized and informed by several factors including severity of symptoms, severity and extent of portal venous obstruction, patient's bleeding risk, and whether the patient is a candidate for liver transplantation. In clinical practice, the benefits of anticoagulation are balanced with the risk of bleeding related to underlying portal hypertension. As an example, we typically anticoagulate patients with cirrhosis and recent, complete PVT who are awaiting liver transplantation. We typically use anticoagulation for patients who are awaiting liver transplantation because portal vein patency impacts the portal vein anastomosis between the donor and recipient. In contrast, we typically do not anticoagulate patients with cirrhosis and recent partial PVT who are asymptomatic and have platelet count <50,000/microL and/or hepatic encephalopathy (ie, fall risk) [3,22].

Prior to initiating anticoagulation in patients with cirrhosis, we perform upper endoscopy to screen for esophageal varices. For patients with high-risk esophageal varices, we use pharmacologic prophylaxis with a nonselective beta blocker or use endoscopic variceal ligation when beta blockers are contraindicated. Screening for esophageal varices and strategies for preventing bleeding are discussed in detail separately. (See "Primary prevention of bleeding from esophageal varices in patients with cirrhosis".)

Observational studies have suggested that anticoagulation was beneficial and safe for patients with cirrhosis and PVT [23-28]. In a meta-analysis of five studies comparing anticoagulation with no anticoagulation in 500 patients with cirrhosis and recent PVT, anticoagulation was associated with higher likelihood of achieving partial or complete portal vein recanalization (58 versus 33 percent; adjusted odds ratio [OR] 3.45; 95% CI 2.22-5.36) and with lower risk of all-cause mortality (25 versus 39 percent; adjusted hazard ratio [HR] 0.59; 95% CI 0.49-0.70) after adjusting for confounding factors (eg, age, thrombosis severity, etiology of cirrhosis) [23]. There were no significant differences in rates of bleeding overall or in rates of portal hypertension-related bleeding between the groups (19 versus 16 percent and 9 versus 14 percent, respectively).

However, these data are limited by lack of randomized trials, variable definitions of bleeding, and the possibility of spontaneous recanalization. As an example, other studies reported a spontaneous recanalization rate of up to 40 percent within three months in patients with cirrhosis and PVT [29,30].

The management of patients with cirrhosis and PVT related to hepatocellular carcinoma is discussed separately. (See "Overview of treatment approaches for hepatocellular carcinoma".)

Initial options

Anticoagulation

Initial administration — We typically use low molecular weight heparin for initial anticoagulation therapy. After the patient’s symptoms have improved and no invasive procedures are planned, we transition to an oral anticoagulant (ie, vitamin K antagonist [VKA] such as warfarin or acenocoumarol). For patients treated with VKA, the target international normalized ratio [INR] is 2 to 3 [7,31]. Dosing and administration of anticoagulant therapy is generally similar to the approach for patients with venous thrombosis at other sites (eg, deep venous thrombosis), and these issues including adverse effects are discussed separately:

●(See "Overview of the treatment of lower extremity deep vein thrombosis (DVT)".)

●(See "Venous thromboembolism: Anticoagulation after initial management".)

●(See "Warfarin and other VKAs: Dosing and adverse effects".)

We generally use anticoagulation for at least six months in all patients who begin anticoagulant therapy. The decision to use long term anticoagulation is informed by multiple factors including extent of thrombosis (ie, into mesenteric veins and risk of intestinal infarction), chronic risk factors for thromboembolism, and presence of cirrhosis [2,4]. (See 'Indications for long-term therapy' below.)

An alternative to VKA as the oral agent is using a direct-acting oral anticoagulant [DOAC]. Although laboratory monitoring is not generally required with DOACs, the absorption of these agents may be limited in patients with intestinal edema related to PVT [3]. Administration and dosing of DOACs are discussed separately. (See "Direct oral anticoagulants (DOACs) and parenteral direct-acting anticoagulants: Dosing and adverse effects".)

Limited data from observational studies suggested that DOACs were effective and safe for treating PVT [32-36]. In a study of 50 patients with cirrhosis and PVT who were initially treated with low molecular weight heparin followed by either edoxaban or warfarin, edoxaban was associated with decreased thrombosis volume as measured by computed tomography (CT), whereas rates of gastrointestinal bleeding were not significantly different between groups (15 versus 7 percent) [35].

Indications for long-term therapy — For patients with PVT who have completed at least six months of anticoagulation therapy, indications for long-term anticoagulation include [37-41]:

●Patients with a chronic thrombotic condition – We may continue anticoagulation indefinitely for some patients with a chronic condition associated with high thrombotic risk. Examples of high-risk thrombotic conditions include antiphospholipid syndrome, myeloproliferative disorders, and homozygous prothrombin gene mutation. (See "Overview of the myeloproliferative neoplasms".)

The goal of chronic anticoagulation is to prevent recurrent thromboses rather than achieve portal vein recanalization. However, monitoring such patients for recurrent symptoms and with serial imaging after they complete at least a six-month course of anticoagulation is also a reasonable approach. (See 'Monitoring' below.)

●Patients with thrombosis involving the mesenteric veins – We continue long-term anticoagulation for patients with PVT extending into the mesenteric veins.

●Patients with cirrhosis – The decision to continue long-term anticoagulation in patients with cirrhosis is individualized and informed by the risk for recurrent thrombosis, bleeding risk, and potential for liver transplantation [1]. Patients with cirrhosis may be at high risk for recurrent thrombosis, although such patients rarely have an underlying thrombotic condition [38,42].

Studies suggested that some patients without a known, high-risk thrombotic condition may still be at increased risk for recurrent thrombosis [38-40]. Risk factors for recurrent thrombosis have included factor VIII levels >150 percent [38], the presence of high molecular risk (HMR)-variants (ie, mutations involved in myeloid disorders different from JAK2, CALR, and MPL genes) [39], and D-dimer ≥500 ng/mL [40]). Monitoring patients with serial imaging is discussed below. (See 'Monitoring' below.)

Monitoring — We monitor patients during and after completing anticoagulation therapy:

●Patients who are anticoagulated – We monitor patients for symptomatic improvement (eg, resolution of abdominal pain). We perform imaging with contrast-enhanced CT or MRI after six months of anticoagulation to assess for recanalization. If recanalization of the portal vein occurs, it typically happens within 6 to 12 months of starting anticoagulation [21,37,43].

●Patients who have completed anticoagulation therapy – For patients who discontinue anticoagulation after a course of therapy, we obtain imaging in three months with contrast-enhanced CT or MRI. We typically continue monitoring patients with abdominal ultrasound with Doppler study once yearly and with contrast-enhanced CT or MRI every four years, although studies to support the imaging method or time intervals for surveillance are lacking.

Observation with serial imaging — For patients with recent PVT who are not treated with anticoagulation, we monitor symptoms and repeat imaging with transabdominal ultrasound with Doppler in one to three months. If there is no clot progression, we perform ultrasound with Doppler every three months for the next six months and then every six months thereafter. If imaging shows clot progression (eg, >50 percent luminal venous obstruction, extension into mesenteric veins), we re-evaluate the patient for anticoagulation therapy. (See 'Anticoagulation' above.)

Subsequent therapy

Pharmacologic or endovascular thrombolysis — For patients with progression of the thrombus or intestinal ischemia with or without signs of impending intestinal infarction, subsequent intervention with thrombolytic therapy or surgical intervention may be necessary [7]. (See "Overview of intestinal ischemia in adults".)

Pharmacologic and/or endovascular thrombolysis are options for patients with progressive disease but who do not require surgical intervention [44]. The goal of pharmacologic thrombolysis (local or systemic) is to achieve long-term recanalization of the portal vein and prevent portal hypertension, especially in patients without cirrhosis. In addition, pharmacologic thrombolysis may be performed in patients who underwent intestinal resection for PVT complicated by ischemia. The goal of postoperative thrombolysis is to achieve recanalization of the portal vein.

Data from small studies and case reports suggested that administering a thrombolytic agent systemically (eg, alteplase) or locally with a catheter by a transjugular or transhepatic route resulted in successful lysis of PVT [44-48]. However, adverse events including significant bleeding have been reported [42,44]. In a series of 22 patients with PVT and intestinal ischemia who did not respond to anticoagulation after a median of nearly 19 days, systemic thrombolysis was given initially [44]. Patients with persistent symptoms despite systemic therapy underwent transjugular intrahepatic portosystemic shunt (TIPS) placement with local clot dissolution therapy, and this treatment protocol was associated with symptom resolution in 20 patients (91 percent) and portal vein recanalization in 19 patients (86 percent). Major adverse events occurred in two patients (liver subcapsular hematoma and neck hematoma related to jugular vein puncture). Of note, this interventional protocol involved a specialized center, and study results have not been replicated. In a prior systematic review that included 71 patients with PVT who underwent thrombolysis (with or without thrombectomy), recanalization of the portal vein was complete in 29 patients (41 percent), partial in 32 patients (45 percent), and unsuccessful in 10 patients (14 percent) [42].

Other interventions — Surgical thrombectomy is an alternative to endovascular intervention, but it is typically reserved for patients who are undergoing laparotomy for intestinal infarction. (See 'Pharmacologic or endovascular thrombolysis' above and "Mesenteric venous thrombosis in adults".)

PROGNOSIS — 

Most patients with recent PVT have a good prognosis when anticoagulation is initiated prior to the onset of intestinal infarction [17,18,42]. Recanalization of the portal vein and preserving existing patency of the superior mesenteric vein minimizes the risk of intestinal infarction. In a cohort of 95 patients with recent (acute) PVT who were treated with anticoagulation, two patients developed intestinal infarction and nine patients developed gastrointestinal bleeding [17]. Two patients (2 percent) died from causes unrelated to thrombosis or anticoagulation therapy.

If left untreated, patients with recent PVT may develop intestinal infarction, although the magnitude of risk is uncertain based on limited data. Infarction may lead to intestinal perforation, peritonitis, shock, multiorgan failure, and death if treatment is not provided promptly [49]. (See "Overview of intestinal ischemia in adults" and "Mesenteric venous thrombosis in adults".)

Patients with untreated, recent PVT may develop chronic PVT and associated complications (eg, portal hypertension). Limited data suggested that spontaneous recanalization of the portal vein was rare among patients without cirrhosis who do not receive anticoagulation [17,18,20]. In a study including 11 patients with untreated PVT that was not related to cirrhosis or malignancy, no patients had spontaneous recanalization after a median follow up of 43 months [18]. (See "Chronic portal vein thrombosis in adults: Clinical features, diagnosis, and management".)

SOCIETY GUIDELINE LINKS — 

Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Hepatic, portal, and splenic vein thrombosis".)

SUMMARY AND RECOMMENDATIONS

●Background – Recent portal vein thrombosis (PVT) is occlusion of the portal vein due to thrombus that developed less than six months ago (table 2). Cirrhosis and thrombotic disorders are risk factors for developing PVT (table 1). (See 'Introduction' above.)

●Clinical features – The spectrum of presentation ranges from asymptomatic patients to those with considerable abdominal pain that develops suddenly or progresses over a few days. Abdominal pain may be accompanied by fever (temperature ≥38°C [100.4°F]), dyspepsia, and/or symptoms related to intestinal ischemia (eg, abdominal distension, back pain, bloody diarrhea). (See 'Clinical features' above.)

Patients with cirrhosis may present with signs of liver decompensation (eg, new onset ascites, variceal bleeding).

●Diagnostic evaluation – The diagnosis of recent PVT is established with abdominal imaging that demonstrates portal venous occlusion in the absence of venous channels within or around the thrombosed portal vein (referred to as cavernous portal transformation) (see 'Diagnostic evaluation' above):

•For patients with a risk factor (eg, cirrhosis, thrombotic disorder) and symptoms suspicious for recent PVT, we obtain a multiphase, contrast-enhanced abdominal CT to establish the diagnosis, evaluate for associated conditions (eg, intra-abdominal infection), evaluate for signs of intestinal ischemia/infarction, and assess the severity and extent of the thrombus.

•For patients with symptoms but no risk factors, we initiate the evaluation with abdominal ultrasound with Doppler study. If ultrasound suggests or confirms the diagnosis of PVT, we obtain multiphase, contrast-enhanced abdominal CT to assess the severity and extent of the thrombus.

•For asymptomatic patients with PVT found incidentally on abdominal ultrasound, we obtain multiphase, contrast-enhanced abdominal CT.

●Post-diagnostic evaluation – The post-diagnostic evaluation includes (see 'Post-diagnosis evaluation' above):

•Determining the severity and extent of PVT

•Assessing for predisposing conditions in patients without known risk factors

•Assessing for underlying malignancy (eg, hepatocellular carcinoma)

●General measures – General measures for patients with PVT include:

•Manage the underlying condition – We initiate therapy for an underlying inflammatory or thrombotic condition (if present) (table 1). As an example, patients with an intra-abdominal infection receive antimicrobial therapy. (See "Pylephlebitis", section on 'Treatment'.)

•Management of an underlying myeloproliferative neoplasm (eg, polycythemia vera, essential thrombocythemia) is discussed separately. (See "Polycythemia vera and secondary polycythemia: Treatment and prognosis" and "Essential thrombocythemia: Treatment and prognosis".)

•Specialist referral – We suggest that patients with PVT are referred to a center with specialty services including hepatology, hematology, and interventional radiology.

●Specific approaches

•Patients without cirrhosis – For patients without cirrhosis, without active bleeding, and without excessive bleeding risk, we recommend anticoagulation rather than expectant management (Grade 1B). The goal of anticoagulation is to restore patency of the thrombosed vein and prevent extension of clot into the mesenteric and/or splenic veins, congestive intestinal ischemia, and progression to chronic PVT. (See 'Patients without cirrhosis' above.)

We typically use low molecular weight heparin for initial therapy. After the patient’s symptoms have improved and no invasive procedures are planned, we transition to an oral anticoagulant (ie, vitamin K antagonist [VKA] such as warfarin or acenocoumarol). For patients treated with VKA, the target international normalized ratio [INR] is 2 to 3.

We typically continue anticoagulation for a minimum of six months. For patients without cirrhosis, indications for long-term anticoagulation include high risk thrombotic conditions and thrombosis extending into the mesenteric veins. (See 'Anticoagulation' above.)

•Patients with cirrhosis – The decision to use anticoagulation in patients with cirrhosis is individualized and informed by several factors including severity of symptoms, severity and extent of portal venous obstruction, patient’s bleeding risk, and whether the patient is a candidate for liver transplantation. (See 'Patients with cirrhosis' above.)

In addition, the pretreatment evaluation for such patients includes upper endoscopy to screen for high-risk esophageal varices. (See "Primary prevention of bleeding from esophageal varices in patients with cirrhosis".)

For patients who are not treated with anticoagulation, we monitor symptoms and perform imaging with transabdominal ultrasound with Doppler in one to three months. If there is no clot progression, we perform ultrasound with Doppler every three months for the next six months and then every six months thereafter. If imaging shows clot progression (eg, >50 percent luminal venous obstruction, extension into mesenteric veins), we re-evaluate the patient for anticoagulation therapy. (See 'Observation with serial imaging' above.)