Thrombophilia testing for prevention of recurrent venous thromboembolism

Open abdomen management for massive intestinal infarction due to acute splanchnic venous thrombosis in a patient with protein S deficiency. A case report

INTRODUCTION

Acute mesenteric ischemia (AMI) refers to the sudden onset of intestinal hypoperfusion that can also result from splanchnic venous occlusion. The portomesenteric venous system (PMVS) is an unusual site of thrombosis in patients with protein S deficiency and its obstruction is a rare cause of AMI. Aim of this report is to illustrate a successful strategy in a case of massive small bowel infarction managed with an open abdomen (OA) approach.

CASE PRESENTATION

A 64 year-old woman presented to the emergency department with acute abdominal pain, rectal bleeding, diarrhea and vomiting. Contrast-enhanced computed tomography (CECT) showed small bowel ischemia and the complete occlusion of all the PMVS branches. Surgery was performed with an OA approach and anticoagulation was immediately begun. Further workup revealed isolated protein S deficiency and history of atrophic gastritis. Thromboprophylaxis with warfarin was started on discharge and no recurrence of thrombotic events was recorded during the one-year follow-up.

DISCUSSION

PMVS thrombosis related to protein S deficiency is a rare condition that can rapidly lead to an acute abdomen. CECT is the gold standard, because it detects splanchnic thrombosis and its possible complications, like bowel ischemia. In case of surgery, a planned second-look operation is the best strategy to assess bowel viability and possible ischemic progression.

CONCLUSIONS

OA management plays a fundamental role in case of resection for bowel ischemia. Patients with thrombosis at an uncommon site should be further investigated for prothrombotic states.

Circulating microparticles and the risk of thrombosis in inherited deficiencies of antithrombin, protein C and protein S

Many subjects carrying inherited thrombophilic defects will never experience venous thromboembolism (VTE) while other individuals developed recurrent VTE with no known additional risk factors. High levels of circulating microparticles (MP) have been associated with increased risk of VTE in patients with factor V Leiden and prothrombin G20210A mutation, suggesting a possible contribution of MP in the hypercoagulability of mild genetic thrombophilia. The role of MP as additional risk factor of VTE in carriers of natural clotting inhibitors defects (severe thrombophilia) has never been assessed. Plasma levels of annexin V-MP, endothelial-derived MP (EMP), platelet-derived MP (PMP), tissue factor-bearing MP (TF+) and the MP procoagulant activity (PPL) were measured in 132 carriers of natural anticoagulant deficiencies (25 antithrombin, 63 protein C and 64 protein S defect) and in 132 age and gender-matched healthy controls. Carriers of natural anticoagulant deficiencies, overall and separately considered, presented with higher median levels of annexin V-MP, EMP, PMP, TF+MP and PPL activity than healthy controls (p< 0.001, < 0.001, < 0.01, 0.025 and 0.03, respectively). Symptomatic carriers with a previous episode of VTE had significantly higher median levels of annexin-V MP than those without VTE (p=0.027). Carriers with high levels of annexin V-MP, EMP and PMP had an adjusted OR for VTE of 3.36 (95 % CI, 1.59 to 7.11), 9.26 (95 % CI, 3.55 to 24.1) and 2.72 (95 %CI, 1.16 to 6.38), respectively. Elevated levels of circulating MP can play a role in carriers of mild and severe inherited thrombophilia. The clinical implications of this association remain to be defined.

Assessing the risk of recurrent venous thromboembolism--a practical approach

Recurrent venous thromboembolism (VTE) is associated with increased morbidity and mortality. This risk is lowered by anticoagulation, with a large effect in the initial phase following the venous thromboembolic event, and with a smaller effect in terms of secondary prevention of recurrence when extended anticoagulation is performed. On the other hand, extended anticoagulation is associated with an increased risk of major bleeding and thus leads to morbidity and mortality. Therefore, it is necessary to assess the risk of recurrence for VTE on an individual basis, and a recommendation for secondary prophylaxis should be specifically based on risk calculation of recurrence of VTE and bleeding. In this review, we provide a comprehensive summary of relevant risk factors for recurrent VTE and a practical approach for assessing the risk of recurrence in daily practice.

[Importance of thrombophilia screening]

Thrombophilia testing denotes a test battery for inherited or acquired features associated with a tendency for clot formation. Currently, it is being used in a frequency and to an extent which is not supported by evidence. In order to protect patients from unnecessary worry and stigmatization, but also for reasons of cost effectiveness, thrombophilia testing should be reduced to a very small number of medically justifiable indications which are outlined in this review.Those indications include the following: secondary prevention of venous thromboembolism in patients from a thrombophilic family, i.e., with two or more first degree relatives with venous thromboembolism (VTE), or patients with suspected antiphospholipid syndrome; women prior to oral contraception or planning to become pregnant if they had no prior VTE but have one or more first-degree relatives with VTE-provided they are willing to follow the consequences of positive test results; women with recurrent miscarriage. The inappropriate indications are discussed as well.The test panel for inherited thrombophilias includes deficiencies of antithrombin, protein C and protein S, factor V Leiden and prothrombin 20210 mutation. Patients with suspicion of antiphospholipid syndrome have to be tested for lupus anticoagulans, anti-cardiolipin antibodies, and anti-β2-glycoprotein I-antibodies. It is important to do the blood sampling at an appropriate point in time.

Management of patients with unprovoked venous thromboembolism: an evidence-based and practical approach

OPINION STATEMENT

The management of patients with unprovoked venous thromboembolism is a common and challenging clinical problem. Although the initial antithrombotic management is well-established, there is uncertainty about the optimal long-term anticoagulant management, specifically whether patients should receive a short (i.e., 3- to 6-month) duration of anticoagulant therapy or indefinite anticoagulation. Factors that may be considered to estimate patients' risk for recurrent thromboembolism include the mode of initial clinical presentation, as deep vein thrombosis or pulmonary embolism, patient sex, antecedent hormonal therapy use, thrombophilia, D-dimer levels, and residual vein occlusion in patients with deep vein thrombosis. Many of these factors have been integrated into clinical prediction guides which stratify patients with unprovoked venous thromboembolism according to their risk for disease recurrence and, thereby, can assist clinicians in decisions about the duration of anticoagulation. The objective of this review is to consider the evidence relating to the clinical significance of purported risk factors and provide a practical case-based approach to guide decisions on duration of anticoagulation for patients with unprovoked venous thromboembolism.

Portomesenteric venous thrombosis as a rare cause of acute abdomen in a young patient: What should be the process of diagnosis and management?

This report aimed to discuss indications for radiological evaluation, laboratory investigation for thrombophilic risk factors, and the duration of anticoagulation therapy in porto-mesenteric venous thrombosis, based on a young patient who presented with acute abdomen and ascites. We investigated the acquired and genetic thrombophilic risk factors and the diagnostic process. Abdominal CT and Doppler US were found to be useful radiological tools in both diagnosis and follow-up of portomesenteric thrombosis. The investigated thrombophilic factors, PT G20210A, MTHFR C677T and MTHFR A1298C, were positive for heterozygous mutations and high levels of lupus anticoagulant and factor VIII were detected. Rapid ascites resolution and an improvement in abdominal pain after meals were observed following anticoagulation. Follow-up examination after six months showed that the portomesenteric thrombosis had completely resolved. Evaluation by CT is recommended for patients with acute abdomen and ascites, especially if ultrasonography failed to show any specific pathology. Several acquired or genetic thrombophilic factors were identified in a patient in whom local precipitating factors were absent. For patients with genetic thrombophilic risk factors and thrombosis at an uncommon site in the body, lifelong treatment with anticoagulants is recommended.

Thrombophilia testing for prevention of recurrent venous thromboembolism

BACKGROUND

Tests for thrombophilia are being performed on a large scale in people after venous thromboembolism (VTE) even though the benefits of testing are still subject to debate. The most important benefit would be a reduction in the risk of recurrent VTE due to the use of additional prophylactic measures. This is an update of a review first published in 2009.

OBJECTIVES

The objective of this review was to assess the benefit of testing for thrombophilia after VTE in terms of risk reduction of recurrent VTE.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 21 2012) and CENTRAL (2012, Issue 5). The authors searched MEDLINE and EMBASE.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that compared the rate of recurrent VTE in participants with VTE who were tested for thrombophilia with the rate in participants with VTE who were not tested were eligible.

DATA COLLECTION AND ANALYSIS

We planned to extract data from identified studies using data extraction forms.

MAIN RESULTS

No studies were included because no RCTs or CCTs could be identified.

AUTHORS' CONCLUSIONS

There are currently no randomized controlled trials or controlled clinical trials that have assessed the benefit(s) of testing for thrombophilia on the risk of recurrent VTE.

Pregnancy-associated venous thromboembolism: prevention and treatment

Pregnancy is associated with an increased risk of venous thromboembolism (VTE) and this condition remains an important cause of maternal morbidity and mortality. The use of anticoagulant therapy for treatment and prophylaxis of VTE during pregnancy is challenging because of the potential for fetal, as well as maternal, complications. Although evidence-based recommendations for the use of anticoagulants have been published, given the paucity of available data, guidelines are based largely upon observational studies and from data in nonpregnant patients. This article reviews the available literature and provides guidance for the management and prevention of VTE during pregnancy.

Diagnosis and treatment of deep-vein thrombosis and approach to venous thromboembolism in obstetrics and gynecology

Deep vein thrombosis (DVT) is a common condition in which the approach to its diagnosis has evolved over the years. Currently, an algorithm strategy combining pre-test probability, D-Dimer testing and compression ultrasound imaging allows for safe and convenient investigation of suspected lower-extremity thrombosis. Patients with low pre-test probability and a negative D-Dimer test result can have proximal DVT excluded without the need for diagnostic imaging. The mainstay of treatment of DVT is anticoagulation therapy, whereas interventions such as thrombolysis and placement of inferior vena cava filters are reserved for special situations. The use of low-molecular-weight heparin (LMW) allows for outpatient management of most patients with DVT. The duration of anticoagulation therapy depends on whether the primary event was idiopathic or secondary to a transient risk factor. More research is required to optimally define the factors that predict an increased risk of recurrent DVT to determine which patients can benefit from extended anticoagulant therapy. DVT is also a serious problem in the antenatal and postpartum period of pregnancy. Thromboembolic complications are the leading cause of both maternal and fetal morbidity and mortality. The incidence of venous thromboembolism during normal pregnancy is six-fold higher than in the general female population of childbearing age. The treatment of DVT during pregnancy deserves special mention, since oral anticoagulation therapy is generally avoided during pregnancy because of the teratogenic effects in the first trimester and the risk of fetal intracranial bleeding in the third trimester. LMW heparin is the treatment of choice for DVT during pregnancy. If acute DVT occurs near term, interrupting anticoagulation therapy may be hazardous because of the risk of pulmonary embolism. In this situation, placement of a retrievable inferior vena cava filter must be considered. However, there is no consensus as to what the appropriate dose should be and whether anti-Xa levels need to be monitored.

Evidence-based approach to thrombophilia testing

Thrombophilia can be identified in about half of all patients presenting with VTE. Testing has increased tremendously for various indications, but whether the results of such tests help in the clinical management of patients has not been settled. I use evidence from observational studies to conclude that testing for hereditary thrombophilia generally does not alter the clinical management of patients with VTE, with occasional exceptions for women at fertile age. Because testing for thrombophilia only serves limited purpose this should not be performed on a routine basis.

Risk assessment for recurrent venous thrombosis

Venous thrombosis is a common disease that frequently recurs. Recurrence can be prevented by anticoagulants, albeit at the cost of bleeding. Thus, assessment of the risk of recurrence is important to balance the risks and benefits of anticoagulation treatment. Many clinical and laboratory risk factors for recurrent venous thrombosis have been established. Nevertheless, prediction of recurrence in an individual patient remains a challenge. Detection of some laboratory markers is associated with only a moderate risk of recurrence, and the relevance of others is not known. Many patients have several risk factors and the effect of combined defects is obscure. Routine screening for these laboratory markers should therefore be abandoned. Risk assessment can be improved by measurement of global markers that encompass the effects of clotting and fibrinolytic disorders. Analysis of preliminary data suggests that risk assessment can also be refined through integration of prothrombotic coagulation changes and clinical risk factors.