Association between thrombophilia and the post-thrombotic syndrome: a systematic review and meta-analysis

Acute phase determinant of post-thrombotic syndrome: A review of the literature

BACKGROUND

Post-thrombotic syndrome (PTS) is the main long-term complication of deep vein thrombosis (DVT). Several therapies are being evaluated to prevent or to treat PTS. Identifying the patients most likely to benefit from these therapies presents a significant challenge.

OBJECTIVES

The objective of this review was to identify risk factors for PTS during the acute phase of DVT.

ELIGIBILITY CRITERIA

We searched the PubMed and Cochrane databases for studies published between January 2000 and January 2021, including randomized clinical trials, meta-analyses, systematic reviews and observational studies.

RESULTS

Risk factors for PTS such as proximal location of DVT, obesity, chronic venous disease, history of DVT are associated with higher risk of PTS. On the initial ultrasound-Doppler, a high thrombotic burden appears to be a predictor of PTS. Among the evaluated biomarkers, some inflammatory markers such as ICAM-1, MMP-1 and MMP-8 appear to be associated with a higher risk of developing PTS. Coagulation disorders are not associated with risk of developing PTS. Role of endothelial biomarkers in predicting PTS has been poorly explored. Lastly, vitamin K antagonist was associated with a higher risk of developing PTS when compared to direct oral anticoagulants and low molecular weight heparin.

CONCLUSIONS

Several risk factors during the acute phase of VTE are associated with an increased risk of developing PTS. There is a high-unmet medical need to identify potential biomarkers for early detection of patients at risk of developing PTS after VTE. Inflammatory and endothelial biomarkers should be explored in larger prospective studies to identify populations that could benefit from new therapies.

Acute and chronic venous occlusion

This review article provides an overview of acute and chronic venous occlusion, a condition that can cause significant morbidity and mortality if not diagnosed and treated promptly. The article begins with an introduction to the anatomy of the venous system, followed by a discussion of the causes and clinical features of venous occlusion. The diagnostic tools available for the assessment of venous occlusion, including imaging modalities such as ultrasound, CT, and MRI, are then discussed, along with their respective advantages and limitations. The article also covers the treatment options for acute and chronic venous occlusion, including anticoagulant therapy and endovascular interventions. This review aims to provide radiologists with an updated understanding of the pathophysiology, diagnosis, and management of acute and chronic venous occlusion.

Current challenges in the prevention and management of post-thrombotic syndrome-towards improved prevention

Post-thrombotic syndrome (PTS) is a common and potentially debilitating complication of deep vein thrombosis (DVT), affecting up to 50% of DVT patients. The consequence of this chronic condition includes reduced quality of life, increased use of the healthcare system and decreased productivity. The societal impact of this condition is projected to increase, given our ageing population and increased burden of thrombotic diseases. Despite significant recent advances in our understanding of PTS, many unanswered questions remain. Currently, there are few effective and proven options for established PTS; hence, the emphasis should be on instituting effective prevention to reduce the progression to PTS. Effective anticoagulation lowers the risk of PTS, with direct oral anticoagulants appearing to outperform vitamin-K antagonists. However, the evidence for elastic compression stockings and endovascular thrombolysis or thrombectomy techniques remains unclear. Accurate identification of individuals at high risk of developing PTS may also improve the targeting of preventative interventions. This review will examine the current body of evidence regarding PTS, with a focus on preventative strategies as well as novel biomarkers.

Biomarkers and the post-thrombotic syndrome: A systematic review of biomarkers associated with the occurrence of the post-thrombotic syndrome after lower extremity deep venous thrombosis

INTRODUCTION

Post-thrombotic syndrome (PTS) is a frequent chronic complication of deep venous thrombosis (DVT). Biomarkers are potentially valuable clinical tools for handling PTS. The purpose of this review was to examine which biomarkers are associated with the development of PTS in adults with lower extremity DVT.

METHODS

We performed a systematic review of all English language prospective studies of biomarkers and PTS published in PubMed and EMBASE. Studies were included if diagnosing DVT by diagnostic imaging and assessing PTS by clinical scales, for example, the Villalta scale. Biomarkers of thrombophilia and pathological clot properties were not assessed. Data was reported qualitatively.

RESULTS

15 prospective studies were included. Studies varied widely in study design and methods of data analysis. Forty-six different biomarkers were examined, with seven being measured in two or more studies. The most frequently studied biomarkers were D-dimer, CRP, and IL-6. Associations between PTS and D-dimer were predominantly significant, while results on CRP and IL-6 were inconsistent. ICAM-1 was consistently associated with PTS in all studies and at all timepoints. IL-10 was significantly related to PTS development in the largest study and at all time points. Adiponectin, tPA, HRG and TAFI, MMP-1 and -8, and TIMP-1 and -2 were significantly associated with PTS in single studies.

CONCLUSION

(1) Further research on biomarkers and PTS is clearly warranted. (2) Significant differences in study designs made it difficult to draw reliable conclusions regarding individual biomarkers. We suggest the implementation of a standardized framework for the study of biomarkers and PTS, to make comparison of future studies more feasible. (3) D-dimer, ICAM-1, IL-10, MMP-1 and 8, TIMP-1, TIMP-2, and adiponectin are clinical biomarkers of particular interest to include in future studies of PTS. Large scale systemic quantitative proteomic analyses of DVT patients could help identify novel biomarkers of interest in PTS-patients.

Translational insights into mechanisms underlying residual venous obstruction and the role of factor XI, P-selectin and GPVI in recurrent venous thromboembolism

BACKGROUND

Residual venous obstruction (RVO) after deep vein thrombosis (DVT) is considered a risk factor of recurrent venous thromboembolism (VTE), arterial events and post-thrombotic syndrome (PTS). We hypothesized thrombo-inflammatory markers might be associated with RVO and clinical outcomes.

MATERIALS AND METHODS

In a DVT cohort with routine RVO-assessment and 5-year follow-up, patients were invited for blood withdrawal after stopping anticoagulants. Thrombin generation potential, coagulation enzyme:inhibitor complexes, soluble platelet markers and clinical markers were measured in platelet-poor plasma. Associations were represented as odds ratio (OR) or hazard ratio (HR) per standard deviation.

RESULTS

Patients with RVO (102/306, 33 %) had higher rates of PTS (24 vs. 12 %, p = 0.008), but similar rates of recurrence (16 vs. 15 %, p = 0.91) and arterial events (7 vs. 4 %, p = 0.26). RVO was associated with thrombin peak height (OR 1.40 [1.04-1.88]), endogenous thrombin potential (ETP, OR 1.35 [1.02-1.79]), and CRP (OR 1.74 [1.10-2.75]). Recurrent VTE was associated with ETP (HR 1.36 [1.03-1.81]), FXIa:C₁-inhibitor (HR 1.34 [1.04-1.72]), thrombin:antithrombin (HR 1.36 [1.16-1.59]), soluble P-selectin (HR 2.30 [1.69-3.11]), soluble glycoprotein VI (sGPVI, HR 1.30 [1.01-1.69]), D-dimer (HR 1.56 [1.31-1.86]), and factor VIII (HR 1.44 [1.15-1.82]). Arterial events were associated with sGPVI (HR 1.80 [1.25-2.59]). PTS was not associated with any marker.

CONCLUSIONS

Our findings indicate RVO was associated with thrombo-inflammation, but this did not predict clinical outcomes in this setting. Importantly, we found recurrent VTE was associated with ongoing coagulation and platelet activation in patients well beyond the acute phase of DVT. Furthermore, sGPVI indicated an increased risk of arterial events, highlighting the role of platelets in arterial thrombosis following DVT.

A predictive model for postthrombotic syndrome in proximal deep vein thrombosis patients

Background

Postthrombotic syndrome (PTS) is the most common long-term complication of deep vein thrombosis (DVT). Predictive models for PTS after hospitalized DVT patients, especially those with proximal DVT for whom preventative intervention decisions need to be made, are rare. We aimed to develop and externally validate a clinical predictive model for PTS in patients with proximal DVT.

Methods

This study was a retrospective, single-center, case-control study. The data used in our model were retrospectively collected from a prospective registry database in which 210 (derivation) and 90 (validation) consecutive patients were first diagnosed with proximal DVT. We developed a nomogram using the multivariate logistic regression model. External validation of our predictive model and previous predictive models in our validation set was assessed by discrimination, calibration, and clinical utility.

Results

Of the 30 candidate predictors, 5 were significantly associated with PTS in our final multivariable model, including the number of signs and symptoms (OR 1.33, 95% CI: 1.17 to 1.53, P<0.001), male sex (OR 1.79, 95% CI: 1.07 to 3.06, P=0.028), varicose vein history (OR 3.02, 95% CI: 1.04 to 7.60, P<0.001), BMI (OR 1.06, 95% CI: 1.00 to 1.12, P=0.052), and chronic DVT (OR 2.66, 95% CI: 1.49 to 4.79, P<0.001). The area under the curve was 0.724 in our predictive model, indicating suitable external performance.

Conclusions

A simple-to-use nomogram effectively predicts the risk of PTS in patients with proximal DVT. This predictive model may be considered for use in clinical care.

Venous Thromboembolism: Genetics and Thrombophilias

Venous thromboembolism (VTE) is a major cause of morbidity and mortality throughout the world. Up to one half of patients who present with VTE will have an underlying thrombophilic defect. This knowledge has led to a widespread practice of testing for such defects in patients who develop VTE. However, identifying a hereditary thrombophilia by itself does not necessarily change outcomes or dictate therapy. Furthermore, family history of VTE by itself can increase an asymptomatic person's VTE risk several-fold, independent of detecting a known inherited thrombophilia. In this article, we will describe the current validated hereditary thrombophilias including their history, prevalence, and association with VTE. With a focus on evaluating both risks and benefits of testing, we will also explore the controversies of why, who, and when to test as well as discuss contemporary societal guidelines. Lastly, we will share how these tests have been integrated into clinical practice and how to best utilize them in the future.

Can we predict and prevent the postthrombotic syndrome?

Postthrombotic syndrome (PTS) remains one of the major late complications of deep vein thrombosis (DVT) with a reported prevalence from 10 to 50%. Many factors were found to be related with the development and severity of PTS such as ipsilateral recurrent DVT, advanced age, obesity, ilio-femoral DVT and primary chronic venous disease presence. Some PTS prediction models have been proposed based on risk factor weight. However, it is still difficult to predict which patient with DVT will develop PTS and thus, the clinical application of these models remains limited. Among the identified problems the heterogeneity of the DVT patient population together with the variety of PTS clinical presentations and difficulties concerning PTS severity assessment should be mentioned. Difficulties on the implementation of the specific and objective PTS identification method have also the significant influence on the research focusing on PTS prevention modalities including risk factor modification, compression treatment, anticoagulation and invasive DVT treatment. In this review, the current approach and knowledge on PTS prediction and prevention are presented, including the conservative and invasive DVT treatment possibilities.

Effect of thrombophilia on clinical outcomes of chronic post-thrombotic patients after iliofemoral stenting with nitinol venous stents

OBJECTIVE

Thrombophilia is a prothrombotic condition that increases the risk of venous thromboembolism. It is unclear whether the presence of thrombophilia alters the clinical outcomes after deep venous stenting. The aim of the present study was to examine the relationship between thrombophilia and outcomes after stenting for post-thrombotic syndrome.

METHODS

Consecutive patients (2012-2017) receiving a nitinol venous stent for chronic post-thrombotic venous occlusive disease with a minimum of 18 months of follow-up in one center using the same anticoagulation protocol were included. The clinical history and thrombophilia testing results were reviewed. The outcomes were stent patency, which was assessed using duplex ultrasonography at 24 hours, 2 and 6 weeks, 3 months, 6 months, and annually thereafter; and reinterventions, which were performed when the stent diameter was <50% or occluded.

RESULTS

Of the 136 patients who had undergone intervention, 55 (40%) had had a provoked deep vein thrombosis (DVT) and 81 (60%) had had an unprovoked DVT and had therefore undergone thrombophilia testing. Of the 81 patients, 38 (47%) had had either inherited (n = 19; 50%) or acquired (n = 19; 50%) thrombophilia. Of the 136 patients who had undergone stenting, 68 had required reintervention (50%) during follow-up to maintain stent patency. Of the 55 patients with a provoked DVT, 29 (53%) had required reintervention. Of the 81 patients with an unprovoked DVT, 39 (48%) had required reintervention (P = .420). Of the 38 patients with unprovoked DVT and thrombophilia, 17 (45%) had required reintervention. Of the 43 patients with unprovoked DVT and no thrombophilia, 22 (51%) had required reintervention (P = .766). The cumulative patency rate was 80% for patients with provoked DVT and 88% for those with unprovoked DVT (P = .193). The presence of thrombophilia was not associated with patency loss (92% cumulative patency for patients with thrombophilia and 84% for patients without thrombophilia; P = .307).

CONCLUSIONS

Using our anticoagulation protocol, patients with and without thrombophilia had similar clinical outcomes after deep venous stenting and should not be excluded from iliofemoral venous stenting. We found no significant differences in outcomes in conjunction with appropriate postoperative anticoagulation therapy.

Thrombus stability explains the factor V Leiden paradox: a mouse model

Humans carrying the factor V Leiden (FVL) variant have a fivefold increased risk for venous thrombosis. However, incidence of deep vein thrombosis (DVT) is proportionally greater than that of pulmonary embolism (PE) in these individuals. This is known as the FVL paradox. We hypothesized that the rate of initial DVT development is similar in FVL and noncarriers, but thrombi in FVL carriers are more stable and develop into a clinically significant DVT more often than in noncarriers. To test this, we induced thrombi in the femoral vein of wild-type (WT), heterozygous (F5L/+), and FVL homozygous (F5L/L) mice. Using intravital microscopy, thrombus size and embolization were visualized and emboli in the lungs were quantified. Compared with WT, femoral vein thrombi in F5L/+ and F5L/L mice were larger and embolized less. Total and large embolic events, the percentage of thrombus that embolized, and PE burden were significantly decreased in F5L/L mice. This suggests that in noncarriers (reflected by WT), a minor injury initially resulting in a small DVT tends to remain small and asymptomatic because of the embolization of the otherwise growing thrombus. Alternatively, the same insult in people with FVL (reflected by F5L/L) leads to thrombus growth as a result of less embolization, and thus symptomatic DVT development.

Venous Thromboembolism Research Priorities: A Scientific Statement From the American Heart Association and the International Society on Thrombosis and Haemostasis

Venous thromboembolism is a major cause of morbidity and mortality. The impact of the US Surgeon General's The Surgeon General's Call to Action to Prevent Deep Vein Thrombosis and Pulmonary Embolism in 2008 has been lower than expected given the public health impact of this disease. This scientific statement highlights future research priorities in venous thromboembolism, developed by experts and a crowdsourcing survey across 16 scientific organizations. At the fundamental research level (T0), researchers need to identify pathobiological causative mechanisms for the 50% of patients with unprovoked venous thromboembolism and to better understand mechanisms that differentiate hemostasis from thrombosis. At the human level (T1), new methods for diagnosing, treating, and preventing venous thromboembolism will allow tailoring of diagnostic and therapeutic approaches to individuals. At the patient level (T2), research efforts are required to understand how foundational evidence impacts care of patients (eg, biomarkers). New treatments, such as catheter-based therapies, require further testing to identify which patients are most likely to experience benefit. At the practice level (T3), translating evidence into practice remains challenging. Areas of overuse and underuse will require evidence-based tools to improve care delivery. At the community and population level (T4), public awareness campaigns need thorough impact assessment. Large population-based cohort studies can elucidate the biological and environmental underpinnings of venous thromboembolism and its complications. To achieve these goals, funding agencies and training programs must support a new generation of scientists and clinicians who work in multidisciplinary teams to solve the pressing public health problem of venous thromboembolism.

Venous thromboembolism research priorities: A scientific statement from the American Heart Association and the International Society on Thrombosis and Haemostasis

Venous thromboembolism (VTE) is a major cause of morbidity and mortality. The impact of the Surgeon General's Call to Action in 2008 has been lower than expected given the public health impact of this disease. This scientific statement highlights future research priorities in VTE, developed by experts and a crowdsourcing survey across 16 scientific organizations. At the fundamental research level (T0), researchers need to identify pathobiologic causative mechanisms for the 50% of patients with unprovoked VTE and better understand mechanisms that differentiate hemostasis from thrombosis. At the human level (T1), new methods for diagnosing, treating, and preventing VTE will allow tailoring of diagnostic and therapeutic approaches to individuals. At the patient level (T2), research efforts are required to understand how foundational evidence impacts care of patients (eg, biomarkers). New treatments, such as catheter-based therapies, require further testing to identify which patients are most likely to experience benefit. At the practice level (T3), translating evidence into practice remains challenging. Areas of overuse and underuse will require evidence-based tools to improve care delivery. At the community and population level (T4), public awareness campaigns need thorough impact assessment. Large population-based cohort studies can elucidate the biologic and environmental underpinings of VTE and its complications. To achieve these goals, funding agencies and training programs must support a new generation of scientists and clinicians who work in multidisciplinary teams to solve the pressing public health problem of VTE.

Determination of Circulating Endothelial Cells and Endothelial Progenitor Cells Using Multicolor Flow Cytometry in Patients with Thrombophilia

BACKGROUND/AIMS

Endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs) have been described as markers of endothelial damage and dysfunction in several diseases, including deep venous thrombosis. Their role in patients with known thrombophilia has not yet been evaluated. Both EPCs and CECs represent extremely rare cell populations. Therefore, it is essential to use standardized methods for their identification and quantification.

METHODS

In this study, we used multicolor flow cytometry to analyze the number of EPCs and CECs in patients with thrombophilia with or without a history of thrombosis. Patients with hematological malignancies after high-dose chemotherapy and patients with acute myocardial infarction were used as positive controls.

RESULTS

EPC and CEC immunophenotypes were determined as CD45dim/-CD34+CD146+CD133+ and CD45dim/-CD34+CD146+CD133-, respectively. Increased levels of endothelial cells were observed in positive control groups. No significant changes in the number of EPCs or CECs were detected in patients with thrombophilia compared to healthy controls.

CONCLUSION

Our optimized multicolor flow cytometry method allows unambiguous identification and quantification of endothelial cells in the peripheral blood. Our results support previous studies showing that elevated levels of CECs could serve as an indicator of endothelial injury or dysfunction. Normal levels of CECs or EPCs were found in patients with thrombophilia.

Thrombophilia, risk factors and prevention

INTRODUCTION

Fifty-three years after the first description of an inherited prothrombotic condition (antithrombin deficiency), our knowledge on hereditary and acquired causes of hypercoagulability that can predispose carriers to venous thromboembolism (VTE) has greatly improved. Areas covered: Main causes of hereditary thrombophilia are summarized alongside new prothrombotic mutations recently discovered. The main causes of acquired thrombophilia, and namely, antiphospholipid antibody syndrome and hyperhomocysteinemia, are also discussed together with other common acquired prothrombotic states characterized by an increase of procoagulant factors and/or a decrease of natural anticoagulants. Finally, suggestions for thromboprophylaxis in carriers of hereditary thrombophilia according to current guidelines/evidence are made for the most challenging high-risk situations (i.e. surgery, pregnancy, contraception, cancer, economy class syndrome) as well as for the prevention of post-thrombotic syndrome. Expert opinion: A carrier of inherited thrombophilia should be evaluated in the framework of other (genetic and/or acquired) coexisting risk factors for first or recurrent VTE when assessing the need and duration of prevention (primary prophylaxis). Prevention strategies should be tailored to each patient and every situational risk factor. The knowledge of the carriership status of severe thrombophilia in the proband can be important to provide asymptomatic relatives with adequate counseling on thrombophilia screening or primary thromboprophylaxis.

How I treat the postthrombotic syndrome

The postthrombotic syndrome (PTS) is a chronic complication of deep vein thrombosis (DVT) that imposes significant morbidity, reduces quality of life, and is costly. After DVT, 20% to 50% of patients will develop PTS, and up to 5% will develop severe PTS. The principal risk factors for PTS are anatomically extensive DVT, recurrent ipsilateral DVT, obesity, and older age. By preventing the initial DVT and DVT recurrence, primary and secondary prophylaxis of DVT will reduce occurrence of PTS. The effectiveness of elastic compression stockings (ECSs) for PTS prevention is controversial. Catheter-directed thrombolysis is not effective to prevent PTS overall but may prevent more severe forms of PTS and should be reserved for select patients with extensive thrombosis, recent symptoms onset, and low bleeding risk. For patients with established PTS, the cornerstone of management is ECS, exercise, and lifestyle modifications. Surgical or endovascular interventions may be considered in refractory cases. Because of a lack of effective therapies, new approaches to preventing and treating PTS are needed. This article uses a case-based approach to discuss risk factors for PTS after DVT, how to diagnose PTS, and available means to prevent and treat PTS, with a focus on new information in the field.

The predictive value of markers of fibrinolysis and endothelial dysfunction in the post thrombotic syndrome

The post thrombotic syndrome (PTS) develops in 20–40% of deep venous thrombosis (DVT) patients. Risk factors for PTS have not been well elucidated. Identification of risk factors would facilitate individualised risk assessment for PTS. We conducted a systematic review to determine whether biomarkers of fibrinolysis or endothelial dysfunction can predict the risk for PTS among DVT patients. Studies were identified by searching the electronic databases PubMed, EMBASE, Scopus and Web of science. We included studies published between 1990 and 2013, measured biomarker levels in adult DVT patients, and reported rates of PTS development. Fourteen studies were included: 11 investigated the association between D-dimer and PTS; three examined fibrinogen; two measured von Willebrand factor; one measured plasminogen activator inhibitor-1; one assessed ADAMTS-13 (A Disintegrin and Metalloprotease with Thrombospondin type 1 repeats) and one measured factor XIII activity. Studies varied with regards to inclusion criteria, definition of PTS, time point and method of biomarker measurement. We were unable to meta-analyse results due to marked clinical heterogeneity. Descriptively, a significant association with PTS was found for D-dimer in four studies and factor XIII in one study. Further prospective research is needed to elucidate whether these markers might be useful to predict PTS development.

Epidemiology of the post-thrombotic syndrome

The post thrombotic syndrome (PTS) refers to clinical manifestations of chronic venous insufficiency (CVI) following a deep-vein thrombosis (DVT). PTS is the most frequent complication of DVT, which develops in 20 to 50% of cases after proximal DVT and is severe in 5-10% of cases. The reported prevalence of PTS differs widely among studies because of differences in study populations, tools used to assess PTS, and time interval between acute DVT and PTS assessment. The two most important predictors of PTS are extensive proximal character of DVT and previous ipsilateral DVT. Other reported risk factors include pre-existing CVI, obesity, quality of anticoagulant treatment, older age and residual venous obstruction. Standardization of PTS assessment tools combined with the development of patient self-reported PTS scales are likely to constitute a breakthrough in research of the epidemiology of PTS, by allowing comparison between studies, meta-analyses and increasing the feasibility of longer follow-up of DVT patients. This should enable identification of patient populations at high risk of severe PTS, new predictors of PTS and targets for potential new treatments. In this perspective, identification of biomarkers that are predictive of PTS such as markers of inflammation is crucial in ongoing research.

Maternal methyltetrahydrofolate reductase gene mutation in patients with missed abortions

Background

Missed abortions are a common problem, often caused by thrombophilia in both recurring and non-recurring cases.

Aim

To determine whether the presence of a mutation in the methyltetrahydrofolate reductase (Mthfr) gene correlates with missed abortions.

Patients and methods

We selected two hundred patients for this study in two groups: the study group, which consisted of one hundred patients with a history of missed abortion; and the control group, which consisted of one hundred patients with no history of missed abortion.

Results

Of the 200 patients, mutations in Mthfr were only found in forty-four patients—thirty-four from the study group and ten from the control group.

Conclusions

Mthfr gene mutation is a common cause of both recurring and non-recurring missed abortions.

The postthrombotic syndrome: current evidence and future challenges

Postthrombotic syndrome (PTS) is a chronic complication of deep vein thrombosis (DVT) that develops in 20-50% of patients. PTS manifests as a spectrum of symptoms and signs of chronic venous insufficiency that can impose significant morbidity and have a negative impact on quality of life. Chronic venous hypertension caused by a combination of residual venous obstruction and valvular reflux is believed to play a major role in the pathophysiology of PTS. The Villalta scale is the most widely applied clinical scale used to diagnose and define PTS. Proximal DVT and recurrent ipsilateral DVT are the two principal established risk factors for PTS, and efforts in recent years have been focused on identifying a combination of clinical and biomarker predictors that will define high-risk patients and possibly new therapeutic targets. The best way to prevent PTS is to prevent the occurrence of DVT, and to provide optimal anticoagulation for the acute phase of DVT once it occurs. Recent years have brought progress in our understanding of the role of endovascular techniques in the prevention and treatment of PTS and the subgroups of patients that may benefit from these modalities. Pharmacomechanical catheter-directed thrombolysis is the most promising interventional modality for prevention of PTS. This review summarizes the current state of evidence on PTS of the lower limbs, and highlights areas where uncertainty still exists that require further research.

Diagnosis and management of factor V Leiden

INTRODUCTION

The discovery of the factor V Leiden (FVL) missense mutation (Arg506Gln) causing factor V resistance to the anticoagulant action of activated protein C was a landmark that allowed a better understanding of the basis of inherited thrombotic risk. FVL mutation is currently the most common known hereditary defect predisposing to venous thrombosis. Areas covered: Novel data-driven FVL diagnosis and therapeutic approaches in the management of FVL carriers in various clinical settings. Brief conclusions on topics of direct clinical relevance including currently available indications for primary and secondary prophylaxis, the management of female, pediatric carriers and asymptomatic relatives. Latest evidence on the association between FVL and cancer, as well as the possible use of direct oral anticoagulant therapy. Expert commentary: Although FVL diagnosis nowadays is highly accurate, many doubts remain regarding the best management and therapeutic protocols. The main role of clinicians is to tailor therapeutic strategies to carriers and their relatives. High familial penetrance, distinctive aspects of the first thrombotic event (provoked/unprovoked, age, etc.) and laboratory biomarkers can guide the optimal management of secondary antithrombotic prophylaxis, primary prophylaxis in asymptomatic individuals, and whether to screen relatives.

Guidance for the prevention and treatment of the post-thrombotic syndrome

The post-thrombotic syndrome (PTS) is a frequent, potentially disabling complication of deep vein thrombosis (DVT) that reduces quality of life and is costly. Clinical manifestations include symptoms and signs such as leg pain and heaviness, edema, redness, telangiectasia, new varicose veins, hyperpigmentation, skin thickening and in severe cases, leg ulcers. The best way to prevent PTS is to prevent DVT with pharmacologic or mechanical thromboprophylaxis used in high risk patients and settings. In patients whose DVT is treated with a vitamin K antagonist, subtherapeutic INRs should be avoided. We do not suggest routine use of elastic compression stockings (ECS) after DVT to prevent PTS, but in patients with acute DVT-related leg swelling that is bothersome, a trial of ECS is reasonable. We suggest that selecting patients for catheter-directed thrombolytic techniques be done on a case-by-case basis, with a focus on patients with extensive thrombosis, recent symptoms onset, and low bleeding risk, who are seen at experienced hospital centers. For patients with established PTS, we suggest prescribing 20–30 mm Hg knee-length ECS to be worn daily. If ineffective, a stronger pressure stocking can be tried. We suggest that intermittent compression devices or pneumatic compression sleeve units be tried in patients with moderate-to-severe PTS whose symptoms are inadequately controlled with ECS alone. We suggest that a supervised exercise training program for 6 months or more is reasonable for PTS patients who can tolerate it. We suggest that management of post-thrombotic ulcers should involve a multidisciplinary approach. We briefly discuss upper extremity PTS and PTS in children.

Guidance for the evaluation and treatment of hereditary and acquired thrombophilia

Thrombophilias are hereditary and/or acquired conditions that predispose patients to thrombosis. Testing for thrombophilia is commonly performed in patients with venous thrombosis and their relatives; however such testing usually does not provide information that impacts management and may result in harm. This manuscript, initiated by the Anticoagulation Forum, provides clinical guidance for thrombophilia testing in five clinical situations: following 1) provoked venous thromboembolism, 2) unprovoked venous thromboembolism; 3) in relatives of patients with thrombosis, 4) in female relatives of patients with thrombosis considering estrogen use; and 5) in female relatives of patients with thrombosis who are considering pregnancy. Additionally, guidance is provided regarding the timing of thrombophilia testing. The role of thrombophilia testing in arterial thrombosis and for evaluation of recurrent pregnancy loss is not addressed. Statements are based on existing guidelines and consensus expert opinion where guidelines are lacking. We recommend that thrombophilia testing not be performed in most situations. When performed, it should be used in a highly selective manner, and only in circumstances where the information obtained will influence a decision important to the patient, and outweigh the potential risks of testing. Testing should not be performed during acute thrombosis or during the initial (3-month) period of anticoagulation.

Predictors for the development of post-thrombotic syndrome in patients with primary lower limb deep venous thrombosis: A case-control study

Introduction Post-thrombotic syndrome is a common and debilitating sequelae of lower limb deep venous thrombosis. Very little awareness is present about the risk factors and about the diagnosis, prevention, and treatment of this condition. Objective The objective of this study is to identify the predictors of post-thrombotic syndrome after lower limb deep venous thrombosis. Materials and methods A case-control study was conducted on all adult patients who were admitted with lower limb deep venous thrombosis at our institution from January 2005 to June 2012. These patients were scheduled for a research clinic visit, which included informed consent, data collection, and physical examination. Patients found to have post-thrombotic syndrome served as cases and those without post-thrombotic syndrome served as controls. Villalta scoring system was used to diagnose the post-thrombotic syndrome and then to assess the severity of the condition in both the groups. Cox regression risk factor analysis was performed to identify the predictors of post-thrombotic syndrome. Results Out of the 125 patients examined, 49 were found to have post-thrombotic syndrome. Risk factors found to be significant were body mass index of more than 35 kg/m² ( n = 13, p = 0.003), history of immobilization ( n = 19, p = 0.003), one or more hypercoagable disorders ( n = 32, p = 0.02), iliofemoral deep venous thrombosis ( n = 18, p = 0.001), complete obstruction on ultrasound ( n = 26, p = 0.016), unstable range of international normalized ratio ( n = 23, p = 0.041) and non-compliance for the use of compressions stockings ( n = 14, p = 0.001). On multivariate analysis, one or more hypercoagable disorder, iliofemoral deep venous thrombosis, and non-compliance to the use of compression stockings were found to be independent risk factors for the development of post-thrombotic syndrome. Conclusion One or more hypercoagable disorders, iliofemoral deep venous thrombosis and non-compliance to the use of compression stockings were independent predictors of post-thrombotic syndrome after deep venous thrombosis. These findings will help prognosticate and prevent development of PTS in similar patient populations.

Postthrombotic syndrome: a 2014 update

PURPOSE OF REVIEW

Postthrombotic syndrome (PTS) is the most frequent complication of deep vein thrombosis. Its pathophysiology is incompletely understood and therapeutic options are limited. This review aims to present and discuss recently published studies that have improved our knowledge related to PTS.

RECENT FINDINGS

From a prognostic point of view, some polymorphisms of plasminogen activator inhibitor-1 and platelet endothelial cell adhesion molecule 1 influence the degree of thrombus resolution after deep vein thrombosis and the subsequent rate of PTS, and could help in predicting the risk of PTS. From a therapeutic point of view, the results of a large multicenter placebo-controlled trial suggest an absence of effectiveness of elastic compression stockings to prevent PTS. In addition, although the Cavent trial of catheter-directed thrombolysis to treat ilio-femoral deep vein thrombosis showed significant reduction in the incidence of PTS that was cost-effective, secondary analyses did not show dramatic improvements in quality of life associated with use of catheter-directed thrombolysis.

SUMMARY

Choice of anticoagulant to treat deep vein thrombosis may represent a new cornerstone of PTS therapeutic management. Studies are needed to assess the impact of new oral anticoagulants and the benefit of extended courses of low molecular weight heparins on the risk of PTS.