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.

Increased levels of histidine-rich glycoprotein are associated with the development of post-thrombotic syndrome.

Denser fibrin networks which are relatively resistant to lysis can predispose to post-thrombotic syndrome (PTS). Histidine-rich glycoprotein (HRG), a blood protein displaying antifibrinolytic properties, is present in fibrin clots. We investigated whether HRG may affect the risk of PTS in relation to alterations to fibrin characteristics. In venous thromboembolism (VTE) patients, we evaluated plasma HRG levels, plasma clot permeability, maximum absorbance, clot lysis time and maximum rate of increase in D-dimer levels released from clots after 3 months of the index event. We excluded patients with cancer and severe comorbidities. After 2 years of follow-up, 48 patients who developed PTS had 18.6% higher HRG at baseline. Baseline HRG positively correlated with clot lysis time, maximum absorbance, and thrombin-activatable fibrinolysis inhibitor (TAFI) activity but was inversely correlated with plasma clot permeability and maximum rate of increase in D-dimer levels released from clots. On multivariate regression model adjusted for age, fibrinogen and glucose, independent predictors of PTS were recurrent VTE, baseline HRG level, and TAFI activity. VTE recurred in 45 patients, including 30 patients with PTS, and this event showed no association with elevated HRG. Our findings suggest that increased HRG levels might contribute to the development of PTS, in part through prothrombotic fibrin clot properties.

Inflammatory biomarkers in deep venous thrombosis organization, resolution, and post-thrombotic syndrome.

OBJECTIVE: Venous thromboembolism (VTE) is a common disease with potentially devastating and long-term sequelae, such as pulmonary embolism and post-thrombotic syndrome (PTS). Given the mortality risk, prevalence of VTE, and limited access to diagnostic imaging, clinically relevant biomarkers for diagnosis and prognostication are needed. Therefore, this review aimed to summarize the data on clinically applicable biomarkers that best indicate acute VTE and chronic PTS. METHODS: We reviewed the medical and scientific literature from 2001 to 2019 for VTE biomarkers. Randomized controlled trials, meta-analyses, and review articles were included. Primary basic research papers with no clinical applicability, opinion papers, institutional guidelines, and case reports were excluded. RESULTS: We highlight the diagnostic value of D-dimer alongside other promising biomarkers, including cellular adhesion molecules, P-selectin, cytokines (interleukins 6 and 10), fibrin monomer complexes, and coagulation factors (factor VIII). CONCLUSIONS: High-sensitivity D-dimer remains the most clinically established VTE biomarker. Current research endeavors are under way to identify more precise biomarkers of VTE and PTS.

Increased inflammation and endothelial markers in patients with late severe post-thrombotic syndrome.

INTRODUCTION: Post-thrombotic syndrome (PTS) is a limiting long-term complication present in 20-50% of patients with deep venous thrombosis (DVT) of the lower limbs. A panel of biomarkers with potential relevance to enhance knowledge on the pathophysiology of PTS was investigated. METHODS: This case-control study included 93 patients with DVT in the lower limbs, 31 with severe PTS (cases) and 62 with mild/no PTS (controls), over 24 months after an acute episode. Thirty-one healthy individuals (HI) with no history of DVT were included as a reference to the population. FVIII activity, D-dimer, inflammatory cytokines, endothelial dysfunction markers, matrix metalloproteinases, and their inhibitors, tissue remodeling and growth factor levels were evaluated. The classification of PTS was, by the Villalta scale. RESULTS: Patients with severe PTS showed elevated levels of CRP, sICAM-1, sE-selectin, and decreased MMP-9 and MCP-1 levels when compared to patients with mild/no PTS. Moreover, DVT patients presented higher levels of FVIII and D-dimer when compared to HI. CONCLUSIONS: DVT patients present an inflammatory status, endothelial dysfunction and altered proteolysis MMPs activity, even a long time after the acute thrombotic episode, which is more significant in severe PTS. These results suggest a possible role of these mediators in the maintenance and worsening of PTS severity.

Venous stasis-induced fibrinolysis prevents thrombosis in mice: role of α2-antiplasmin.

Stasis of venous blood triggers deep vein thrombosis by activating coagulation, yet its effects on the fibrinolytic system are not fully understood. We examined the relationship between stasis, fibrinolysis, and the development of experimental venous thrombosis. Effects of stasis-induced deep vein thrombosis and fibrinolysis on thrombosis were examined by inferior vena cava ligation in congenic mice with and without α2-antiplasmin (α2AP), the primary inhibitor of plasmin. Venous thrombus weights were measured and thrombus composition was determined by Martius scarlet blue and immunofluorescence staining. Venous thrombi from α2AP+/+ mice contained plasminogen activators, plasminogen activator inhibitor-1, plasminogen, and α2AP, which changed with thrombus age. Normal, α2AP+/+ mice developed large, occlusive thrombi within 5 hours after ligation; thrombi were even larger in plasminogen-deficient mice (P < .001). No significant thrombus formation was seen in α2AP-/- mice (P < .0001) or in α2AP+/+ mice treated with an α2AP-inactivating antibody (P < .001). Venous stasis activated fibrinolysis, measured by D-dimer levels, in α2AP-/- mice vs α2AP+/+ mice (P < .05). Inhibition of fibrinolysis by the indirect plasmin inhibitor ε-aminocaproic acid or by α2AP restored thrombosis in α2AP-/- mice. In addition to its effects on acute thrombosis, thrombus formation was also markedly suppressed in α2AP-/- mice vs α2AP+/+ mice (P < .0001) 1, 7, and 14 days after ligation. We conclude that experimental venous stasis activates the fibrinolytic system to block the development of venous thrombosis. Suppression of fibrinolysis by α2AP appears essential for stasis-induced thrombus development, which suggests that targeting α2AP may prove useful for preventing venous thrombosis.

Venous Thrombosis and Post-Thrombotic Syndrome: From Novel Biomarkers to Biology.

Deep vein thrombosis (DVT) is a common disease that carries serious ramifications for patients, including pulmonary embolism and post-thrombotic syndrome (PTS). Although standard treatment for DVT is anticoagulation, this carries an added risk of bleeding and increased medication monitoring. Identifying those at risk for DVT and PTS can be difficult, and current research with murine models is helping to illuminate the biologic changes associated with these two disorders. Potential novel biomarkers for improving the diagnosis of DVT and PTS include ICAM-1, P-selectin, and cell-free DNA. Inhibition of factor XI, P- and E-selectin, and neutrophil extracellular traps holds promise for novel clinical treatment of DVT. Experimental research on PTS suggests potential cellular and mediator therapy targets of TLR9, MMP-2 and-9, PAI-1, and IL-6. Although many important concepts and mechanisms have been elucidated through research on DVT and PTS, more work must be done to translate experimental findings to the clinical arena. This review examines the currently used murine models of DVT, biomarkers involved in the pathophysiology and diagnosis of DVT and PTS, and potential pharmacologic targets for PTS treatment.

Electrical calf muscle stimulation in patients with post-thrombotic syndrome and residual venous obstruction after anticoagulation therapy.

BACKGROUND: The aim of this study was to assess the impact of electrical calf muscle stimulation (EMS) on clinical and ultrasound outcomes in patients with post-thrombotic syndrome (PTS) and residual venous obstruction (RVO). METHODS: This was a prospective, comparative, non-randomized clinical trial involving patients who had completed a standard 6-month course of anticoagulation therapy for a first episode of unprovoked femoro-popliteal DVT and had signs of RVO in the affected veins and PTS as shown by a Villalta Score of >5. A blinded outcome assessor performed the ultrasound evaluations. A total of 60 patients in the age range from 40 to 86 years (mean 58.5±11.4) consisting of 38 men and 22 women were enrolled. They were divided into two groups of 30 participants each. Both groups (experimental and control) were treated by active walking, below-knee graduated compression stockings, and micronized purified flavonoid fraction. In the experimental group, EMS with «Veinoplus VI¼ device (three applications for 30 min every day) was also used. The patients were followed for 12 months with monthly DUS to reveal recurrent DVT and changes in RVO. The clinical criteria for treatment efficacy included changes in Villalta, VCSS and CIVIQ-20 scores. RESULTS: Recurrent DVT was found in seven of 30 patients in the control group and in zero of 30 patients in the experimental group (23.3% versus 0%, P=0.01). Through the follow-up period the degree of RVO decreased in all affected veins in both groups (P<0.01). The most significant changes were found in the popliteal vein; 60.8% decreased to 28.8% in the experimental group and 50.9% to 27.3% in the control group (P<0.01) with significant differences between the groups (P<0.01). VCSS, Villalta and CIVIQ-20 scores also significantly decreased in both groups (P<0.01). In the group with EMS, changes in the current parameters were more intensive (P<0.01). CONCLUSIONS: There is an ongoing process of deep vein recanalization during the 12 months after anticoagulant therapy cessation. Use of EMS in PTS treatment allows for reduction of recurrent DVT rates, increase the speed of deep vein recanalization and leads to additional improvement in the clinical PTS outcomes.

Elevated leptin and decreased adiponectin independently predict the post-thrombotic syndrome in obese and non-obese patients.

Post-thrombotic syndrome (PTS) is a common complication of deep vein thrombosis (DVT). Little is known about the involvement of adipokines in the pathogenesis of DVT. We evaluated whether adipokines can predict PTS. In a prospective cohort study, 320 DVT patients aged 70 years or less were enrolled. Serum adiponectin, leptin and resistin levels were measured three months since the index first-ever DVT. After 2 years' follow-up PTS was diagnosed in 83 of 309 available patients (26.9%) who had 13.9% lower adiponectin and 16% higher leptin levels compared with the remainder (both p < 0.0001). No PTS-associated differences in C-reactive protein, fibrinogen, D-dimer, plasminogen activator inhibitor-1 and resistin were observed. The multivariable logistic regression adjusted for age, sex, obesity and tissue plasminogen activator (tPa) showed that lower adiponectin (odds ratio [OR], 0.42; 95% confidence interval [CI], 0.31-0.56) and higher leptin levels (OR, 1.49; 95% CI, 1.31-1.69) are independent predictors for PTS. Obesity-stratified logistic regression analysis confirmed that lower adiponectin (OR, 0.49; 95% CI, 0.38-0.64) and higher leptin (OR, 1.41; 95% Cl, 1.25-1.58) levels predicted PTS. Our findings showed that lower adiponectin and higher leptin measured 3 months after DVT, regardless of obesity, can independently predict PTS, which suggests novel links between adipokines and thrombosis.

ABO blood group and the risk of post-thrombotic syndrome.

Post-thrombotic syndrome (PTS) has been associated to DVT recurrence, increased FVIII, inflammatory biomarker plasma levels, and persistence of vein obstruction. These same features have also been widely reported in non-O blood type subjects. Our aim was to investigate the correlation between the incidence of PTS and ABO blood types. Consecutive patients referred to the Department of Medicine of University of Padua between January 2004 and January 2012 following the diagnosis of a first episode of proximal DVT were enrolled. The presence of PTS was assessed via the Villalta scale at predefined time points (3, 6, 12, 18, 24, 36 months). Hazard ratio (HR) for PTS development was calculated in non-O (exposed) vs O blood (unexposed) type patients. Out of 671 eligible patients, 606 were enrolled. Overall, 192 (31.7%) patients developed PTS: 142 (34.5%) non-O and 50 (25.6%) O blood type patients. Individuals with non-O blood group were associated with a significantly higher risk to develop PTS (HR 1.53, 95% CI, 1.05-2.24; p = 0.028) than O group. Non-O blood type might be a risk factor for the development of PTS.

Post thrombotic syndrome following deep vein thrombosis in paediatric patients.

Background Although well characterised in adults, less is known about post-thrombotic syndrome in children. In this review, current knowledge regarding paediatric post-thrombotic syndrome is summarised, with particular emphasis on pathophysiology, aetiology, diagnosis and management. Methods A Medline literature review was performed using search terms 'post thrombotic syndrome', 'post phlebitic syndrome', paediatric and children. Relevant articles were identified and included for summation analysis. Results The incident of paediatric venous thromboembolism is rising. Deep vein thrombosis can cause venous hypertension through a combination of venous reflux, venous obstruction and impairment of the calf muscle pump, leading to development of post-thrombotic syndrome. In children, this is more likely to occur if deep vein thrombosis diagnosis and treatment are delayed, if a higher number of vessels are involved, and if factors such as D-dimer are elevated at diagnosis and throughout treatment. Post-thrombotic syndrome occurs in about 26% of paediatric deep vein thrombosis, though the results of individual studies vary widely. A number of tools exist to diagnose paediatric post-thrombotic syndrome, including the modified Villalta scale and Manco-Johnson instrument. Once post-thrombotic syndrome develops, the mainstay of treatment remains supportive, with little evidence of benefit from pharmacological measures. Conclusion Surgical or interventional treatment is not advised except in exceptional cirumstances, due to variable prognosis of PTS in paediatric populations with rising incidence of paediatric venous thromboembolism, it follows that the prevalence of post-thrombotic syndrome in children may also increase. Evidence-based venous thromboembolism prevention strategies need to be implemented for prevention of deep vein thrombosis, but when it does occur, deep vein thrombosis requires prompt and effective treatment to prevent post-thrombotic syndrome. Optimum treatment strategies for post-thrombotic syndrome require further investigation.

Obesity Paradox in Patients With Deep Venous Thrombosis.

We aimed to investigate the association between obesity and deep venous thrombosis (DVT) in a country with a high prevalence of obesity. This is a retrospective cohort study of patients who presented with DVT between 2008 and 2012. Data were analyzed and compared based on body mass index (BMI), and patients were classified into normal (<25), overweight (≥25 to <30), obese I (30 to <35), obese II (35 to <40), and obese III (≥40). Among 662 patients with DVT, 28% were overweight and 49% were obese. The mean age was 50.3 (16.5) years, and 51% were females. Diabetes mellitus and prior venous thromboembolism were significantly higher among obese patients. History of malignancy was more common in nonobese patients. Protein S and antithrombin III deficiency and hyperhomocysteinemia were more prevalent among morbid obese patients. Also, obese patients had higher incidence of thrombosis in the distal veins ( P = .03). Warfarin use and long-term therapy were more frequent in obese than nonobese. Postthrombotic syndrome was comparable in obese and nonobese groups. Recurrent DVT was higher in obese I ( P < .01), whereas mortality rates were greater in nonobese groups ( P = .001). Malignancy, diabetes mellitus, and common femoral vein involvement were predictors of mortality, whereas BMI ≥30 was the predictor of survival. Cox regression models showed that after adjusting for age, sex, pulmonary embolism, and duration of warfarin treatment, BMI ≥40 had better survival (hazard ratio: 0.177, 95% confidence interval: 0.045-0.691, P = .013). There is a significant association between obesity and DVT. Obese patients have characteristic risk factors and better survival. This obesity paradox needs further studies to assess its clinical and pharmacotherapeutic implications.

Severe postthrombotic syndrome is associated with characteristic sonographic pattern of the residual thrombosis.

Postthrombotic syndrome (PTS) may affect 50% of patients with deep venous thrombosis, 5-10% of them may present severe manifestations. The causes for PTS development and severity have not been well established. This study evaluated whether PTS may be associated with the presence, and echogenicity, of the residual vein thrombosis (RVT). We included patients with a history of deep venous thrombosis in the past 58 months. These patients were further evaluated for PTS diagnosis, clinical comorbidities, plasma levels of D-dimer, serum levels of C-reactive protein and for the presence of RVT. Particularly, RVT was detected by ultrasound examination and the residual thrombi echogenicity was determined by grayscale median (GSM). Fifty-six patients were included, of which 41 presented PTS. Mild PTS was detected in 23 patients, moderate PTS in 11 and severe PTS in seven patients. Patients with severe PTS showed higher body mass index, higher abdominal circumference and higher C-reactive protein levels when compared with the other patients (P = 0.007, P = 0.002, P = 0.02, respectively). The ultrasound-generated GSM was significantly lower in patients with severe PTS compared with patients with mild-moderate PTS or no PTS (median = 24, 35 and 41, respectively; P = 0.04). A GSM value less than 25, which was consistent with a hypoechoic RVT, was the best cut-off value to discriminate patients with severe PTS from those with mild or moderate PTS and those without PTS. RVT is a common finding among patients with PTS and the echogenicity of the RVT may impact the severity of PTS.

Reduced plasma fibrin clot permeability and susceptibility to lysis are associated with increased risk of postthrombotic syndrome.

BACKGROUND: The postthrombotic syndrome (PTS) is a severe complication of deep vein thrombosis (DVT). Reduced plasma clot permeability and lysability have been linked to DVT and residual vein obstruction. OBJECTIVES We investigated whether altered fibrin clot properties are associated with the occurrence of PTS. PATIENTS AND METHODS: Plasma fibrin clot permeability (Ks ) and lysability were investigated in a cohort of 197 consecutive patients aged 18 to 65 years recruited 3 months following the first-ever DVT. Patients with severe thrombophilia or comorbidities known to adversely affect clot phenotype were ineligible. RESULTS: During a 1-year follow-up PTS developed in 48 (24%) patients, who were characterized by lower Ks , prolonged fibrin clot lysis time (CLT) and slower release of D-dimer from clots (D-Drate ), together with higher plasma D-dimer, C-reactive protein and thrombin-activatable fibrinolysis inhibitor (TAFI). No PTS-associated differences in fibrinogen, thrombin generation, factor VIII, other fibrinolysis proteins and the quality of anticoagulation were observed. Ks (r = -0.71), CLT (r = 0.45), D-Drate (r = -0.30) and TAFI activity (r = 0.38) were associated with the Villalta scale (all P < 0.05). Recurrent VTE occurred also more commonly in PTS patients during follow-up and the 26 (13.2%) patients had lower Ks , longer CLT and lower D-Drate (all P < 0.05). A multivariate model adjusted for age, body mass index, fibrinogen and glucose showed that independent predictors of PTS were idiopathic DVT, plasma D-dimer, Ks , D-Drate , tissue plasminogen activator and TAFI activity. CONCLUSIONS: This study demonstrates that formation of more compact fibrin clots displaying impaired susceptibility to lysis predisposes to PTS.

The role of inflammation in post-thrombotic syndrome after pregnancy-related deep vein thrombosis: A population-based, cross-sectional study.

Previous studies suggest that inflammation may play a role in the pathophysiology of post-thrombotic syndrome (PTS). The aims of the present study were to evaluate markers of inflammation as possible predictors for PTS after pregnancy-related deep vein thrombosis (DVT). We included 182 women with a pregnancy-related DVT during 1990-2003 and 314 controls. All women answered a questionnaire and donated a blood sample in 2006. PTS was diagnosed when a self-reported Villalta score was above 4. The following predictors of PTS were included: high sensitivity C-reactive protein (hsCRP), interleukin (IL)-6, IL-8, IL-10, monocyte chemotactic protein (MCP)-1, transforming growth factor (TGF)-ß1, platelet derived growth factor (PDGF)-BB, and the two adhesion molecules intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1. High values were defined as above median value among controls. We found that 41% of cases were diagnosed with PTS 3-16years after index pregnancy. In univariate analyses, high values of hsCRP, IL-6, and IL-10 were significantly associated with PTS with ORs 2.3 (95% CI; 1.2-4.2, p=0.008), 1.9 (1.0-3.5, p=0.04), and 10.8 (1.3-89.8, p=0.01), respectively. Only hsCRP, which has previously been found to be independently associated with PTS, was independently associated with PTS in a multivariate logistic regression model, when adjusting for proximal DVT occurring postpartum, age above 33years, and smoking (adjusted OR 2.4; 95% CI 1.2-4.8, p=0.01). We conclude that hsCRP was associated with PTS 3-16years after pregnancy-related DVT.

Clot structure and fibrinolytic potential in patients with post thrombotic syndrome.

INTRODUCTION: Post-thrombotic syndrome (PTS) is a chronic sequel of deep vein thrombosis (DVT). The clot structure and fibrinolytic potential in PTS is currently unknown. OBJECTIVE: To assess the fibrinolytic potential and clot structure in patients with PTS. MATERIALS AND METHODS: Patients with a history of DVT were included in a case-control study: patients with PTS (cases n=30) and without PTS (controls n=30), and 30 apparently healthy individuals (HI) without venous thromboembolism (VTE) or venous insufficiency were enrolled. Fibrinolysis and clot structure were assessed by turbidimetric assays, permeation, and confocal microscopy. Fibrinogen was measured by Clauss and fibrinogen γ' by ELISA. RESULTS: We observed a significant trend of decreasing maximum turbidity from HI (median 0.52 [IQR 0.46-0.62]), to controls (0.49 [IQR 0.41-0.55]), to cases (0.46 [IQR 0.39-0.49]) p=0.020. Fibrinogen was lower in patients (cases and controls) (3.69g/L [IQR 3.31-4.26]) compared to HI (4.17 [IQR 3.69-4.65]) p=0.041. Patients with recurrent VTE had lower maximum turbidity and lower permeation than patients with one episode of VTE; (0.31 [IQR 0.25-0.39] versus 0.38 [IQR 0.34-0.44] p=0.008) and (6.0×10(-9)/cm(2) [IQR 5.1-7.9] versus 7.7×10(-9)/cm(2) [IQR 6.0-10.0] p=0.047) respectively, at equal fibrinogen levels. There were no differences in lysis time, confocal microscopy, or fibrinogen γ'. CONCLUSIONS: Lower maximum turbidity, indicating a tendency towards thinner fibres and denser clots, was found in patients with PTS as well as in patients with recurrent VTE. Fibrinogen levels did not explain these differences in clot structure. The abnormal clot structure may contribute to the increased thrombotic risk profile in patients with PTS.

Plasma MMP and TIMP evaluation in patients with deep venous thrombosis: could they have a predictive role in the development of post-thrombotic syndrome?

Post-thrombotic syndrome (PTS) is a condition that can develop in about half of the patients with deep vein thrombosis (DVT) of lower limbs. In the present study, we evaluated the expression of inflammatory biomarkers in the early phases of DVT and their correlation with the onset of PTS. Patients were enrolled after the first episode of DVT and were followed up for 1, 4, 8, 12 and 18 months. At each visit, blood sample was collected to evaluate plasma levels of matrix metalloproteinase (MMP)-1,-2,-3,-7,-8 and -9 MMP inhibitors, TIMP-1,-2, neutrophil gelatinase-associated lipocalin (NGAL) and cytokines TNF-α and IL-6. Analysis included 201 patients [86 males (42·79%) and 115 females (57·21%); average age 56 ± 7 years]. Of the 201 patients, 47 (23·38%; 21 males, 26 females) developed PTS during the follow-up period. The control group was made up of 60 individuals without DVT (22 males and 38 females). High plasma levels of MMPs, NGAL and cytokines were recorded during the acute phase after DVT. Moreover, patients with PTS showed higher levels of MMP-1 and MMP-8 with respect to patients without PTS. There is a close relationship between DVT, the individual risk of PTS and specific biomarkers such as MMPs and other related molecules, which may help guide prevention and therapy based on the patient's individual risk profile, and has to be studied in future.

Controversies in venous thromboembolism--2015.

Venous thromboembolism is commonly encountered both in the community and the in-patient setting. Despite major advances in diagnosis and treatment, there remain challenges in several clinical areas as a result of insufficient evidence to guide practice. This review covers six controversial topics, summarizes the best available evidence, and presents recommendations for practice. The clinical relevance of calf vein thrombosis and sub-segmental pulmonary embolism are often questioned; this has implications for both their diagnosis and management. The role of thrombolysis for the treatment of deep vein thrombosis (DVT) is discussed in consideration of the potential benefits and risks. Residual vein obstruction has been proposed as a predictor of recurrent thrombosis; we consider its relevance when determining the duration of anticoagulant treatment. The post-thrombotic syndrome (PTS) can be a disabling and costly consequence of DVT with limited options for prevention and treatment. We review the available evidence related to compression stockings for PTS prevention. Finally, the relationship between cancer and VTE is well recognized and this review considers the value of screening for occult cancer in patients with unprovoked VTE.

Predictive value of markers of inflammation in the postthrombotic syndrome: a systematic review: inflammatory biomarkers and PTS.

BACKGROUND: The postthrombotic syndrome (PTS) is a chronic complication of deep vein thrombosis (DVT). Inflammation may contribute to its pathophysiology. OBJECTIVES: We conducted a systematic review of studies that analyzed the association between biomarkers of inflammation and PTS in DVT patients. METHODS: The electronic databases PubMed, EMBASE, Medline, Scopus and Web of Science were searched for studies published until March 2015 that measured blood inflammation biomarker levels in adult DVT patients and reported their association with PTS development. Two reviewers independently performed full text assessment and data extraction. RESULTS: Ten studies were included. Nine reported on the association between C-reactive protein and PTS; Interleukin (IL)-6 was measured in six studies; IL-8 in four studies; Intracellular adhesion molecule (ICAM)-1 in three studies; IL-10 and vascular cell adhesion molecule-1 in two studies; and monocyte chemotactic protein-1, matrix metalloprotease-9, P-Selectin, tumor necrosis factor α and erythrocyte sedimentation rate were measured in one study. Studies differed in terms of populations included, exclusion criteria, methods used for biomarker measurement and statistical measures of association between biomarkers and PTS. We were able to metaanalyze results only for IL-6 and found no significant association. Descriptively, ICAM-1 was significantly associated with PTS in two out of three studies that measured it. Other biomarkers did not demonstrate a significant association with PTS. CONCLUSIONS: Our systematic review found conflicting results regarding the role of inflammatory biomarkers as predictors of PTS. ICAM -1 appears to be a promising marker for further investigation.