The post-thrombotic syndrome: progress and pitfalls

Clinical relevance of fibrin fiber diameter during different phases of pregnancy

INTRODUCTION

Pregnancy-related deep vein thrombosis (DVT) is most common during the late phase of pregnancy and the first 6-weeks postpartum. Pregnancy-related DVT can have long-term complications, specifically post-thrombotic syndrome (PTS). Fibrin network ultrastructure is altered during pregnancy and post-partum. It is therefore essential to evaluate fibrin fiber diameter during and after pregnancy as this may provide insight into pregnancy-related DVT and subsequent PTS.

MATERIALS AND METHODS

The fibrin network ultrastructure of females during different phases of pregnancy was compared to that of non-pregnant females to assess possible changes to the fibrin network morphology and fibrin fiber diameter using scanning electron microscopy micrographs.

RESULTS

The fibrin network arrangement was more densely packed during different phases of pregnancy, corresponding to earlier findings. Fibrin diameter decreased significantly during pregnancy, with the greatest decrease occurring during the late phase of pregnancy. The fractal dimensions of fibrin micrographs increased significantly during pregnancy compared to nonpregnant females. These changes are indicative of a simultaneous hypercoagulable and hypofibrinolytic state and correspond to the increased risk of DVT and subsequent development of PTS.

CONCLUSION

It is critical to identify "vulnerable" females with an inflammatory predisposition to prevent possible DVT and subsequent PTS. Modifiable risk factors like obesity and smoking should be addressed to alleviate the burden on the coagulation system. Morphological and viscoelastic techniques are crucial in assessing the coagulatory health of females during pregnancy.

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.

Post-thrombotic syndrome after catheter-directed thrombolysis for deep vein thrombosis (CaVenT): 5-year follow-up results of an open-label, randomised controlled trial

BACKGROUND

Post-thrombotic syndrome is a common complication after acute proximal deep vein thrombosis (DVT) and is associated with reduced quality of life and a substantial cost burden. In the 2-year results of the CaVenT study, additional catheter-directed thrombolysis reduced the risk of post-thrombotic syndrome by 14% compared with conventional therapy, but did not affect quality of life. In this study we report results at the 5-year follow-up, aiming to assess whether findings for post-thrombotic syndrome and quality of life have persisted.

METHODS

Between Jan 3, 2006, and Dec 22, 2009, we recruited patients aged 18-75 years with a first-time high proximal leg DVT from 20 hospitals in the Norwegian southeastern health region. With sealed envelopes, participants were randomly assigned (1:1) to standard treatment with compression stockings and anticoagulants (control group) or to standard treatment plus catheter-directed thrombolysis with alteplase within 21 days from symptom onset. Pre-specified outcomes in this analysis were post-thrombotic syndrome at 5 years as assessed with the Villalta score and scores for quality of life at 5 years with EQ-5D and the disease-specific VEINES-QOL/Sym. Analyses were by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00251771.

FINDINGS

At 5 year follow-up (last date Oct 14, 2014), data were available for 176 patients (84% of the 209 patients originally randomised)--87 originally assigned to catheter-directed thrombolysis and 89 originally assigned to the control group. 37 patients (43%; 95% CI 33-53) allocated to catheter-directed thrombolysis developed post-thrombotic syndrome, compared with 63 (71%; 95% CI 61-79) allocated to the control group (p<0·0001), corresponding to an absolute risk reduction of 28% (95% CI 14-42) and a number needed to treat of 4 (95% CI 2-7). Four (5%) patients assigned to catheter-directed thrombolysis and one (1%) to standard treatment had severe post-thrombotic syndrome (Villalta score ≥ 15 or presence of an ulcer). Quality-of-life scores with either assessment scale did not differ between the treatment groups.

INTERPRETATION

Additional catheter-directed thrombolysis resulted in a persistent and increased clinical benefit during follow-up for up to 5 years, supporting the use of additional catheter-directed thrombolysis in patients with extensive proximal DVT. However, allocation to this therapy did not lead to better quality of life. The optimal endovascular thrombolytic approach needs further investigation.

FUNDING

Southeastern Norway Regional Health Authority, the Research Council of Norway, University of Oslo, Oslo University Hospital.

Venous Thromboembolism in Patients Diagnosed With Lung Cancer

PURPOSE

Considering the high prevalence of lung cancer, our purpose was to summarize the existing literature to identify the several factors that contribute to the increased risk of venous thromboembolism (VTE) in patients with lung cancer and to analyze the current recommendations for thromboprophylaxis and treatment of VTE in those patients.

METHODS

We searched the Medline and EMBASE databases from February 1985 to February 2014 to identify retrospective and prospective randomized controlled studies that investigate one or more risk factors for VTEs in patients with lung cancer.

RESULTS

A VTE is a major complication for patients diagnosed with lung cancer. The risk factors for VTE events in patients with lung cancer consist of cancer-related (histological type and stage of cancer), treatment-related (surgery, chemotherapy, angiogenic agents, and supportive care agents), and patient-related factors (comorbidities, immobility, performance status, and prior thrombosis). Low-molecular-weight heparins are recommended for long-term treatment of cancer-associated thrombosis. Duration of anticoagulant therapy beyond 6 months should be based on individual clinical evaluation. Thromboprophylaxis for patients with lung cancer during hospitalization and immediate postoperative period is well established.

CONCLUSIONS

Efforts to assess thrombotic risk in patients with lung cancer may improve therapeutic and preventive strategies in the future, with final goal to minimize the burden and consequences of thrombotic events in patients with lung cancer.

A Multicenter, Retrospective Study of the Effectiveness of the Trellis-8 System in the Treatment of Proximal Lower-Extremity Deep Vein Thrombosis

BACKGROUND

Deep vein thrombosis (DVT) occurs in up to 600,000 patients in the United States annually and can lead to long-term morbidity because of the post-thrombotic syndrome. The multicenter isolated-pharmacomechanical thrombolysis device (ISOL-8) study was designed to determine the safety and efficacy of the Trellis™-8 peripheral infusion system when used as the primary intervention to achieve DVT thrombolysis in patients with proximal lower-extremity occlusive DVT, and track the incidence and severity of the post-thrombotic syndrome (PTS) symptoms in patients 2 years after treatment.

METHODS

Data were collected retrospectively from 6 centers on patients treated with the Trellis-8 system, an isolated-pharmacomechanical thrombolysis device (IPMTD). Patients with occlusive lower-extremity DVT involving at least the iliac and/or common femoral vein were included. Patient demographics, medical history, procedure outcomes, complications, and follow-up venous duplex and Venous Clinical Severity Score (VCSS) were collected through 24 months. Data analysis of outcomes were performed at 1 and 12 months. A 24-month analysis was not performed because of the small number of patients for whom 24-month data could be collected.

RESULTS

A total of 151 limbs in 139 patients were treated with IPMTD. The mean ± standard deviation (SD) procedure time was 122.6 ± 63.4 min. Single session treatment was delivered in 69.9% (93 of 133) of cases. Occlusive DVT extended from the femoral into the external and/or common iliac vessel segments in most of the cases (113 of 151 limbs; 74.8%). Before treatment, 23.2% (35 of 151) of the treated limbs, based on a history of prior ipsilateral DVT or preoperative imaging revealing chronic venous scar, were expected to have some chronic venous disease despite presenting with acute symptoms. After treatment, 43.7% (66 of 151) of the limbs showed evidence of chronic thrombus. The average amount (mean ± SD) of thrombolysis, as determined by venogram, was highest in patients who had acute thrombus (81 ± 19.7%), compared with subacute thrombus (61 ± 22.5%) and complex cases involving acute and/or subacute thrombus on chronic scar (56 ± 26.5%). VCSS scoring showed the number of patients with none and/or mild pain, varicose veins, and skin changes at 1-month remained stable at 12 months whereas the percent of patients with none and/or mild venous edema improved from 71.7% at 1 month (38 of 53) to 86.8% (46 of 53) at 12 months. Twenty-four-month follow-up data were available for only 15% (23 of 151) of patients. No clinically significant pulmonary emboli or major periprocedural bleeding events were reported.

CONCLUSIONS

Patients with acute lower-extremity DVT involving the proximal veins can be safely and successfully treated with IPMTD. Major procedural bleeding was absent. The occurrence of severe PTS after primary treatment with Trellis-8 system IPMTD is low. Further long-term follow-up data are needed to confirm the benefit of intervention for thrombus removal compared with standard medical management.

The May-Husni Procedure: A Reappraisal

OBJECTIVES

The May-Husni procedure is a rarely used saphenofemoral venous bypass because of the small number of patients with post-thrombotic segmental femoral vein obstruction alone and the lack of validated selection criteria. There are only a few institutional series reporting the use of this technique. The purpose of this report is to present the author's experience and critically review the literature.

METHODS

Within a 13 year period 12 patients with venous claudication, skin pigmentation, and severe pain and swelling of their legs underwent the May-Husni procedure. Their median age was 57 years (41-69 years). Imaging showed segmental venous obstruction of the femoral vein in all patients and poor or no inflow from the deep femoral vein. Two patients were lost to follow up and the remaining 10 patients were reviewed with a median follow up of 60 months (26-72 months).

RESULTS

The saphenopopliteal bypass remained patent in all patients at follow up. The development of reflux of the saphenous conduit in four patients did not affect the clinical improvement. Venous claudication resolved, hyper-pigmentation improved, and pain was relieved in all patients. Recanalization of the femoral vein 3 years following thrombosis was followed by recurrence of the post-thrombotic symptoms in two patients.

CONCLUSIONS

These results indicate that a highly selected subgroup of patients with severe symptomatic post-thrombotic syndrome secondary to chronic segmental obstruction of the femoral vein do well after the May-Husni procedure. In order to refine the criteria for the selection of patients who may benefit from this operation, there is a need for more studies that use a combination of hemodynamic and validated scales that diagnose and grade the severity of post-thrombotic syndrome.

Compression Therapy in the Prevention of Postthrombotic Syndrome: A Systematic Review and Meta-Analysis

Although compression therapy has been widely used after deep vein thrombosis (DVT), its efficacy in prevention of postthrombotic syndrome (PTS) remains disputable. We aimed to update the meta-analysis to comprehensively evaluate the effect of compression therapy on the prevention of PTS in adult patients after DVT.PubMed, Embase, and Cochrane library databases were systematically searched. Randomized controlled trials (RCTs) evaluating the preventive effect of compression therapy on PTS in adult patients after DVT were included. The primary outcome was the incidence of PTS. All meta-analyses were performed using random-effects models regardless of the heterogeneity. Subgroup and sensitivity analysis were also performed to examine the robustness of the pooled effects according to our predesigned plan. Potential publication bias was assessed.Eight RCTs with 1598 patients were included. Overall, compression therapy could significantly reduce the incidence of PTS (estimate 0.68, 95% confidence interval [CI] 0.52-0.90; P = 0.007). However, it was only associated with a reduction in the incidence of mild/moderate PTS (relative risk [RR] 0.66, 95% CI 0.46-0.93; P = 0.019) but not in the incidence of severe PTS (RR 0.64, 95% CI 0.27-1.50; P = 0.31). Additionally, compression therapy failed to reduce the incidence of recurrent venous thromboembolism (RR 0.91, 95% CI 0.65-1.27; P = 0.58), the incidence of ulceration (RR 0.74, 95% CI 0.36-1.53; P = 0.42), or mortality (RR 0.99, 95% CI 0.72-1.37; P = 0.96). No publication bias was observed.Current evidence still supports compression therapy to be a clinical practice for prophylaxis of PTS in adult patients after DVT. However, our findings should be cautiously interpreted because of heterogeneity and hence more large-scale and well-designed RCTs are still warranted.

Long-Term Results of Catheter-Directed Thrombolysis Combined with Iliac Vein Stenting for Iliofemoral Deep Vein Thrombosis

Purpose:

We were going to access the effect of catheter-directed thrombolytic therapy (CDT) on post-thrombotic syndrome (PTS) and the long term effects of iliac vein stenting in acute iliofemoral deep vein thrombosis (IFDVT).

Materials and Methods:

Fifty-six limbs in fifty-one patients (46 unilateral, 5 bilateral) were included from November 2001 through December 2007. Patients were classified based on the method of treatment: with stent implantation (n=37) and without stent implantation (n=19). The Villalta scale was chosen to assess for severity of PTS. The validated outcome measures were compared between the treatment groups. Statistical analysis was estimated according to the Kaplan-Meier test and Pearson chi-square test.

Results:

Mean age was 57±13 years (range, 27–76 years). Mean follow up duration was 56±12 months (range, 24–144 months). Overall 5-year primary patency rate was 66.1% (77.8% in the stenting group and 42.1% in the non-stenting group) and showed statistically significant difference between the two groups (P=0.02). The recurrence rate of deep vein thrombosis was 10/37 (27.1%) in the stenting group and 11/19 (57.9%) in the non-stenting group, respectively, which showed statistically significant difference between the two groups (P=0.024). Overall incidence of mild PTS was 8/30 (26.7%): 4/13 (30.8%) in the stenting group and 4/17 (23.5%) in the non-stenting group. None of the other factors showed statistically significant difference between the groups.

Conclusion:

Long term results of CDT in IFDVT were acceptable, and stent implantation to the iliac segment seems to have a good effect on the long term results. Therefore CDT with simultaneous stenting is recommended to improve long term results of IFDVT, if indicated.

Treatment options for venous thromboembolism: lessons learnt from clinical trials

Venous thromboembolism (VTE), comprising deep vein thrombosis and pulmonary embolism, is a common condition associated with a significant clinical and economic burden. Anticoagulant therapy is the mainstay of treatment for VTE, having been shown to reduce the risk of death in patients with pulmonary embolism, and recurrence or extension of thrombi in patients with deep vein thrombosis during the initial treatment period. Long-term anticoagulation is indicated in some individuals with VTE, depending on individual risk of VTE recurrence and anticoagulant-related bleeding. Management of VTE in clinical practice is often complex because patients' characteristics and treatment needs may differ considerably from those encountered in clinical trials. Current guidelines recommend the use of either low molecular weight heparins or fondaparinux overlapping with and followed by a vitamin K antagonist for the initial treatment of VTE, with the vitamin K antagonist continued when long-term anticoagulation is required. These traditional anticoagulants have practical limitations that have led to the development of direct oral anticoagulants that directly target either Factor Xa or thrombin and are administered at a fixed dose without the need for routine coagulation monitoring. This review discusses practical considerations for hospital physicians and haematologists in the management of VTE treatment, including the potential for the direct oral anticoagulants to simplify treatment.

Prevalence of skin problems and leg ulceration in a sample of young injecting drug users

Background

Drug users suffer harm from the injecting process, and clinical services are reporting increasing numbers presenting with skin-related problems such as abscesses and leg ulcers. Skin breakdown can lead to long-term health problems and increased service costs and is often the first indication of serious systemic ill health. The extent of skin problems in injecting drug users has not previously been quantified empirically, and there is a dearth of robust topical literature. Where skin problems have been reported, this is often without clear definition and generic terms such as ‘soft tissue infection’ are used which lack specificity. The aim of this study was to identify the range and extent of skin problems including leg ulceration in a sample of injecting drug users. Definitions of skin problems were developed and applied to descriptions from drug users to improve rigour.

Methods

Data were collected in needle exchanges and methadone clinics across Glasgow, Scotland, from both current and former drug injectors using face-to-face interviews.

Results

Two hundred participants were recruited, of which 74% (n = 148) were males and 26% (n = 52) were females. The age range was 21–44 years (mean 35 years). Just under two thirds (64%, n = 127) were currently injecting or had injected within the last 6 months, and 36% (n = 73) had previously injected and had not injected for more than 6 months.

Sixty per cent (n = 120) of the sample had experienced a skin problem, and the majority reported more than one problem. Most common were abscesses, lumps, track marks and leg ulcers. Fifteen per cent (n = 30) of all participants reported having had a leg ulcer.

Conclusions

This is an original empirical study which demonstrated unique findings of a high prevalence of skin disease (60%) and surprisingly high rates of leg ulceration (15%). Skin disease in injecting drug users is clearly widespread. Leg ulceration in particular is a chronic recurring condition that is costly to treat and has long-term implications for drug users and services caring for current or former injectors long after illicit drug use has ceased.

Biomarkers for post thrombotic syndrome: a case-control study

INTRODUCTION

There is limited knowledge on the etiology of post thrombotic syndrome (PTS), although several mechanisms have been proposed. The objectives are to explore the role of different pathogenic mechanisms for PTS, through measurement of an elaborate panel of biomarkers in patients with and without PTS.

MATERIALS AND METHODS

Patients with a history of deep vein thrombosis (DVT) with PTS (cases) and without PTS after minimal 2years follow-up (controls), were selected from the outpatient clinic of two Dutch hospitals. As a reference to the normal population healthy individuals (HI) without a history of venous thromboembolism were invited to participate. The population consisted of: 26 cases, 27 controls, and 26 HI. A panel of predefined biomarkers was measured in venous blood.

RESULTS

D-dimer showed a decreasing trend from cases to controls to HI; p=0.010. Thrombin/antithrombin complex levels were significantly higher in cases than in controls; p=0.032, and HI; p=0.017. APC-ratio was significantly lower in cases compared to controls; p=0.032, and HI; p=0.011. A significant trend of increasing proTAFI from cases, to controls, and HI; p=0.002 was found. There were no differences in inflammatory markers (CRP, Interleukin-6, Interleukin-8). Thrombomodulin, tissue-plasminogen activator, and von Willebrand factor were higher in patients compared to HI. There was a significant trend of decreasing sVCAM, from cases, to controls, and HI; p=0.029.

CONCLUSIONS

Patients with PTS displayed increased coagulation activity, an altered pattern of fibrinolytic marker expression, and increased endothelial activation. We found no evidence of systemic inflammation in patients with PTS at 63months since the last DVT.

What predicts outcome after recanalization of chronic venous obstruction: hemodynamic factors, stent geometry, patient selection, anticoagulation or other factors?

In this review we evaluated the effect of different suggested factors associate with the outcome after recanalization of chronic venous obstruction (CVO).

Hemodynamic factors:

Based upon literature no clear suggestions can be made to identify the risk of stent occlusion in association with the hemodynamic effects. However it is evident that ensuring optimal in- and outflow of the stented tract is key in maintaining the patency.

Patient selection:

Noninvasive imaging modalities are used to divide patients in three subgroups based on the place and extension of post-thrombotic changes. Moreover it should be noted that AV fistula in selected patients can reduce the risk of thrombosis or re-occlusion.

Geometry:

Excessive oversizing of the stent and stent compression from outside are considered to be associated with stent occlusion. Additionally, overlapping rigid stents, unnatural angel between stents and in-stent kinking are other geometrical factors related to worse outcome after venous recanalization.

Anticoagulation:

Adequate peri-and postoperative anticoagulation has a crutial role in stent patency. There is no data regarding the duration of anticoagulation therapy and recommendations vary between 6 weeks to 6 months.

Result:

impaired inflow or outflow, presence of a hypercoagulability, total number of treated segments and use of stents designed for implantation in arterial system are associated with decreased stent patency.

Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-leg immobilization

BACKGROUND

Immobilization of the lower leg is associated with venous thromboembolism (VTE). Low molecular weight heparin (LMWH) is an anticoagulant treatment which might be used in adult patients with lower-leg immobilization to prevent deep venous thrombosis (DVT) and its complications. This is an update of the review first published in 2008.

OBJECTIVES

To assess the effectiveness of low molecular weight heparin for the prevention of venous thromboembolism in patients with lower-leg immobilization in an ambulant setting.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched June 2013) and CENTRAL (2013, Issue 5).

SELECTION CRITERIA

Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-leg immobilization. Immobilization was by means of a plaster cast or brace.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager (RevMan 5).

MAIN RESULTS

We included six RCTs fulfilling the above criteria with a total of 1490 patients. We found an incidence of VTE ranging from 4.3% to 40% in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization (event rates ranging from 0% to 37%; odds ratio (OR) 0.49; fixed 95% confidence interval (CI) 0.34 to 0.72; with minimal evidence of heterogeneity with an I(2) of 20%, P = 0. 29). Comparable results were seen in the following subcategories: operated patients, conservatively treated patients, patients with fractures, patients with soft-tissue injuries, patients with proximal thrombosis, patients with distal thrombosis and patients with below-knee casts. Complications of major bleeding events were extremely rare (0.3%) and there were no reports of heparin-induced thrombocytopenia.

AUTHORS' CONCLUSIONS

Use of LMWH in outpatients significantly reduces VTE when immobilization of the lower leg is required.

Percutaneous pharmacomechanical thrombectomy for acute iliofemoral deep vein thrombosis: A suitability study

Objectives

Percutaneous pharmacomechanical thrombectomy is an emerging therapy for acute deep vein thrombosis and may reduce long-term incidence of post-thrombotic syndrome. This study investigates the proportion of patients presenting with lower limb deep vein thrombosis who are potentially suitable for percutaneous pharmacomechanical thrombectomy.

Methods

A retrospective review of all duplex ultrasound scans for lower limb deep vein thrombosis over two-year period at a regional vascular unit was conducted. All acute occlusive iliofemoral deep vein thrombosis were screened for percutaneous pharmacomechanical thrombectomy suitability according to predefined criteria.

Results

There were 2513 duplex ultrasound scans for suspected lower limb deep vein thrombosis in the two-year period. There were 120 cases of acute occlusive iliofemoral deep vein thrombosis. After application of inclusion and exclusion criteria 48 out of 120 (40%) patients were identified as potential candidates for percutaneous pharmacomechanical thrombectomy.

Conclusions

This indicates that a large randomised trial of percutaneous pharmacomechanical thrombectomy is feasible given expected recruitment rates in a multicentre study.

Residual rates of reflux and obstruction and their correlation to post-thrombotic syndrome in a randomized study on catheter-directed thrombolysis for deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) often results in venous valvular incompetence and incomplete recanalization, followed by post-thrombotic syndrome (PTS). Treatment with additional catheter-directed thrombolysis (CDT) in patients with an iliofemoral DVT has been shown to reduce the frequency of PTS. The objective of this study was to assess the effect of CDT on venous reflux and patency and to identify possible predictors for the development of PTS.

METHODS

Open, multicenter, randomized, controlled clinical trial. Patients (18-75 years) with a first-time iliofemoral DVT were randomized to receive conventional treatment with anticoagulation and compression stockings or CDT in addition to conventional treatment. Follow-up after 6 and 24 months included ultrasound and air plethysmography for evaluation of venous reflux and patency. PTS was assessed with the Villalta score. Possible predictors of PTS were analyzed in multivariate logistic regression models.

RESULTS

Following additional CDT, deep venous reflux was detected in 65.2% (95% confidence interval [CI], 54.8-74.2) of patients at 6 months and 66.7% (95% CI, 56.4-75.6) at 24 months. The absolute risk reduction of deep venous reflux was 11.9% (95% CI, 1.1-24.9) after 6 months and 16.5% (95% CI, 4.2-28.8) after 24 months in the CDT arm compared with controls. Correspondingly, venous patency was regained in 65.9% (95% CI, 55.5-75.0) of patients at 6 months and 74.7% (95% CI, 64.9-82.6) after 24 months. Patency was regained in 18.5% (95% CI, 4.4-32.6) more patients after 6 months and 15.1% (95% CI, 1.8-28.5) more patients after 24 months compared with controls. Independent of treatment allocation, patients with fully recanalized and competent deep veins at 6-month follow-up had a 40.5% (95% CI, 26.4-54.7) absolute risk reduction of developing PTS compared with patients with abnormal vein assessment. Reflux and lack of patency at 6 months were found to be independent predictors of PTS development in patients treated with CDT (odds ratio, 8.3; 95% CI, 2.6-26.8 for patients with reflux, and odds ratio, 0.17; 95% CI, 0.06-0.49 for patients with patency).

CONCLUSIONS

Additional CDT improved patency and reduced reflux. Both parameters were found to be strong predictors of PTS in patients treated with CDT. Noninvasive vein assessments of patency and reflux may be helpful to identify and monitor patients at high risk of PTS. Our findings provide evidence for the importance of early recanalization with CDT for acute iliofemoral DVT.

Basic data related to thrombolytic therapy for acute venous thrombosis

BACKGROUND

Treatment guidelines for thrombolysis in iliofemoral deep venous thrombosis (DVT) are based on a limited number of observational and prospective studies. The acute venous thrombosis: thrombus removal with adjunctive catheter-directed thrombolysis (ATTRACT) trial will be the first large, multicenter randomized control trial to evaluate the relative advantages of several current treatment strategies. The objective of this study was to summarize the existing data that inform the use of catheter-directed thrombolysis (CDT) or pharmacomechanical thrombectomy in the management of acute iliofemoral DVT.

METHODS

A search of the current literature was done using PubMed, Ovid, and Cochrane databases for all available articles published up to December 2013.

RESULTS

Of those studies, which included at least 25 patients, 19 case series were identified from 1996 to 2012. Treatment groups included anticoagulation, surgical thrombectomy, pharmacomechanical thrombectomy, and CDT. Cases observed in each ranged from 26 to 101. Three studies were identified which derived data from national multicenter registries. Only 2 randomized control trials were identified from 2002 to 2012. Both support the use of CDT over anticoagulation alone for treatment of iliofemoral DVT.

CONCLUSIONS

Present treatment guidelines for acute iliofemoral DVT have been in flux and are derived from a relatively small amount of clinical data. They are summarized here in anticipation of results from the ongoing ATTRACT trial.

Development and use of sulodexide in vascular diseases: implications for treatment

Sulodexide (SDX), a sulfated polysaccharide complex extracted from porcine intestinal mucosa, is a blend of two glycosaminoglycan (GAG) entities, namely a fast-moving heparin (HP) fraction and a dermatan sulfate (DS; 20%) component. The compound is unique among HP-like substances in that it is biologically active by both the parenteral and oral routes. A main feature of the agent is to undergo extensive absorption by the vascular endothelium. For this reason, in preclinical studies, SDX administered parenterally displays an antithrombotic action similar to that of HPs but associated with fewer alterations of the blood clotting mechanisms and tests, thus being much less conducive to bleeding risk than HPs. When given orally, SDX is associated with minimal changes in classic coagulation tests, but maintains a number of important effects on the structure and function of endothelial cells (EC), and the intercellular matrix. These activities include prevention or restoration of the integrity and permeability of EC, counteraction versus chemical, toxic or metabolic EC injury, regulation of EC-blood cell interactions, inhibition of microvascular inflammatory and proliferative changes, and other similar effects, thus allowing oral SDX to be considered as an endothelial-protecting agent. The best available clinical evidence of the efficacy of SDX administered orally with or without an initial parenteral phase is the following: alleviation of symptoms in chronic venous disease and especially acceleration of healing of venous leg ulcers; prevention of cardiovascular events in survivors after acute myocardial infarction; marked improvement of intermittent claudication in patients with peripheral occlusive arterial disease; and abatement of proteinuria in patients with diabetic nephropathy that may contribute to the amelioration or stabilization of kidney function. Although further clinical trials are warranted, SDX is presently widely accepted in many countries as an effective and safe long-term, endothelial-protecting drug.

Association between Thrombophilia and the Post-Thrombotic Syndrome

The post thrombotic syndrome (PTS) is a chronic condition that develops in 20%–40% of deep vein thrombosis (DVT) patients. While risk factors that predispose to the development of venous thromboembolism (VTE) are widely known, factors that influence the development of PTS after DVT have not been well elucidated. Over 10% of the general population is affected by one or more identifiable inherited thrombophilias which have been shown to underlie at least 1/3 of cases of VTE. The various thrombophilias are important risk factors for VTE, but it is unknown whether they also increase the risk for development of PTS. We performed a review of studies that have reported on the association between thrombophilia and the development of PTS in populations of patients with DVT and with chronic venous ulcers. Studies vary with regards to the definition of PTS, study design, follow-up period, and present conflicting results. Based on these results, the question of whether thrombophilia predisposes to the development of PTS remains unanswered.

Deep venous thrombosis following different isolated lower extremity fractures: what is known about prevalences, locations, risk factors and prophylaxis?

INTRODUCTION

Deep venous thrombosis (DVT) offers a high risk of morbidity and mortality, especially in case of pulmonary embolism. Precise data as to DVT after isolated lower extremity fractures (ILEFs) are rare. Even organizations like the American Academy of Orthopaedic Surgeons or the American College of Chest Physicians do not state exact recommendations as to optimal DVT prophylaxis (ppx) after ILEFs.

PREVALENCE

The incidence of DVT ranges from 5 to 86 % depending on the fracture whereas femur fractures offer the highest risk for clotting. The incidence seems to decrease in more distal fractures.

LOCATION

The risk to develop proximal clots is likely low, however, especially these are feared by surgeons. DVT can occur in both the injured and uninjured leg with a trend for higher incidences in the injured leg.

RISK FACTORS

Risk factors for DVT after ILEF seem to be similar to risk factors for DVT development after orthopaedic surgery and in general. Risk factors caused by surgeons are the use of a tourniquet, prolonged operative time and a delay from injury to surgery.

PROPHYLAXIS

Low molecular weight heparin is favoured by many authors, however, warfarin and acetylsalicylic acid are also used. Clear recommendations are still missing.

CONCLUSION

The rate of morbidity caused by DVT after ILEF is poorly understood so far. Exact data on prevalences are missing and optimal DVT prophylaxis still has to be defined.

Ultrasound-accelerated catheter-directed thrombolysis for the management of postpartum deep venous thrombosis

Pregnancy and the postpartum period are associated with an increased risk of venous thromboembolism, which remains an important cause of maternal morbidity and mortality. Although oral or systemic anticoagulation therapy may minimize thrombus propagation, it remains ineffective in removing thrombus burden and consequently does not prevent post-thrombotic syndrome. A novel technique, ultrasound accelerated catheter directed thrombolysis (UACDT), has been developed to rapidly and completely resolve thrombus. While pregnancy and the postpartum period are generally considered as contraindications for thrombolysis, we demonstrate in this case study the safety and effectiveness of using UACDT to treat symptomatic, postpartum, iliofemoral deep vein thrombosis after only an overnight infusion.

Markers of coagulation, fibrinolysis and inflammation in relation to post-thrombotic syndrome

BACKGROUND

Post-thrombotic syndrome (PTS) occurs in 20-50% of patients after a deep venous thrombosis (DVT). It is difficult to accurately predict which patients will develop PTS. Biomarkers could be a valuable tool for PTS risk assessment.

OBJECTIVES

To investigate whether increased levels of factor (F)VIII, C-reactive protein (CRP) or D-dimer, over time, are associated with the development of PTS in patients after an acute DVT.

METHODS

PTS status was assessed using the Villalta scale. Blood sampling was performed at three points during follow-up.

RESULTS

A cohort of 228 consecutive patients was included after an acute DVT. At T1 (12 months after index DVT), both levels of D-dimer (median 725 ng mL(-1) [interquartile range, IQR 400-1400[ vs. 378 ng mL(-1) [251-652] P=0.004) and CRP (median 3.9 mg L(-1) [IQR 1.6-8.5] vs. 2.4 mg L(-1) [1.0-4.3] P=0.018) were increased in patients with PTS, compared with patients without PTS. Factor (F)VIII was not associated with PTS. In the multivariate logistic regression analysis, varicosities (odds ratio [OR] 13.4 95% confidence interval [CI] 3.0-59.1 P=0.001), a previous ipsilateral DVT (OR 6.3 95% CI 1.5-26.9 P=0.012) and CRP>5 mg L(-1) on T1 (OR 8.0 95% CI 2.4-26.4 P=0.001) were significantly associated with PTS.

CONCLUSIONS

Besides previous ipsilateral DVT and varicosities, CRP>5 mg L(-1) at T1 was strongly and independently associated with PTS. Persistent inflammation rather than hypercoagulability might be the most important etiological factor in PTS, and may be a target for future therapy. The development of a risk score for PTS, including both clinical risk factors and biomarker levels, such as CRP, might be desirable.

Sulodexide in the treatment of chronic venous disease

Chronic venous disease encompasses a range of venous disorders, including those involving the lower limbs resulting from venous hypertension. The spectrum of chronic venous disease signs and symptoms shows variable severity, ranging from mild (aching, pain, and varicose veins) to severe (venous ulcers). The pathophysiology of chronic venous disease is characterized by venous hypertension, which triggers endothelial dysfunction and inflammation leading to microcirculatory and tissue damage, and eventually to varicose veins and venous ulcers. Sulodexide is an orally active mixture of glycosaminoglycan (GAG) polysaccharides with established antithrombotic and profibrinolytic activity. The agent is used in the treatment of a number of vascular disorders with increased risk of thrombosis, including intermittent claudication, peripheral arterial occlusive disease and post-myocardial infarction. Sulodexide differs from heparin because it is orally bioavailable and has a longer half-life and a smaller effect on systemic clotting and bleeding. An increasing body of preclinical evidence shows that sulodexide also exerts anti-inflammatory, endothelial-protective, and pleiotropic effects, supporting its potential efficacy in the treatment of chronic venous disease. Clinical studies of sulodexide have shown that the agent is associated with significant improvements in the clinical signs and symptoms of venous ulcers, and is therefore a recommended therapy in combination with local wound care and bandages for patients with persistent venous leg ulcers. Preliminary evidence supports the use of sulodexide in the prevention of recurrent deep venous thrombosis. Sulodexide was generally safe and well tolerated in clinical trials, without hemorrhagic complications. Sulodexide therefore appears to be a favorable option for the treatment of all stages of chronic venous disease and for the prevention of disease progression.

Rationale and Indications for Aggressive Early Thrombus Removal

Randomized clinical trials have defined anticoagulation with unfractionated or low-molecular-weight heparin followed by warfarin as a standard therapy for acute deep venous thrombosis (DVT). Such treatment is highly effective in preventing recurrent venous thromboembolism with a low risk of bleeding, but provides imperfect protection against development of the post-thrombotic syndrome. Several strategies of early thrombus removal, including surgical venous thrombectomy, catheter-directed thrombolysis and pharmacomechanical thrombectomy have been developed with the goal of reducing the incidence of the post-thrombotic syndrome by restoring venous patency and preserving valvular function. Although clinical judgement and a consideration of the individual patient's medical condition and values are required, early thrombus removal strategies should be considered in selected patients with phlegmasia cerulea dolens and those with a first episode of acute iliofemoral thrombosis of less than 14 days duration.

Evaluating the Role of Compression Stockings in Preventing Post thrombotic Syndrome: A Review of the Literature

Background. Postthrombotic syndrome (PTS) is a burdensome and costly complication of deep vein thrombosis (DVT). Up to 50% of patients with DVT will develop the disease within two years following the diagnosis of acute DVT. Various risk factors for developing PTS have been identified and different modalities have been used to prevent its development. Compression stockings have been studied for the prevention of PTS in patients diagnosed with proximal DVT. Methods. MEDLINE and EMBASE databases were searched to identify relevant original articles. Results. Several trials including two metaanalyses have examined the role of compression stockings for the prevention of PTS. Although most trials showed significant reduction in the development of PTS with the use of compression stockings, limitations in study design prevent the generalizability of the data. Two studies supported an individualized tailored duration especially in patients at low risk for developing the syndrome. A randomized double-blind placebo-controlled trial involving 800 patients is currently ongoing and may confirm the results of older studies. Conclusions. Clinical trials support the use of compression stockings in patients diagnosed with proximal DVT for the prevention of PTS.

Long-term outcome after additional catheter-directed thrombolysis versus standard treatment for acute iliofemoral deep vein thrombosis (the CaVenT study): a randomised controlled trial

BACKGROUND

Conventional anticoagulant treatment for acute deep vein thrombosis (DVT) effectively prevents thrombus extension and recurrence, but does not dissolve the clot, and many patients develop post-thrombotic syndrome (PTS). We aimed to examine whether additional treatment with catheter-directed thrombolysis (CDT) using alteplase reduced development of PTS.

METHODS

Participants in this open-label, randomised controlled trial were recruited from 20 hospitals in the Norwegian southeastern health region. Patients aged 18-75 years with a first-time iliofemoral DVT were included within 21 days from symptom onset. Patients were randomly assigned (1:1) by picking lowest number of sealed envelopes to conventional treatment alone or additional CDT. Randomisation was stratified for involvement of the pelvic veins with blocks of six. We assessed two co-primary outcomes: frequency of PTS as assessed by Villalta score at 24 months, and iliofemoral patency after 6 months. Analyses were by intention to treat. This trial is registered at ClinicalTrials.gov, NCT00251771.

FINDINGS

209 patients were randomly assigned to treatment groups (108 control, 101 CDT). At completion of 24 months' follow-up, data for clinical status were available for 189 patients (90%; 99 control, 90 CDT). At 24 months, 37 (41·1%, 95% CI 31·5-51·4) patients allocated additional CDT presented with PTS compared with 55 (55·6%, 95% CI 45·7-65·0) in the control group (p=0·047). The difference in PTS corresponds to an absolute risk reduction of 14·4% (95% CI 0·2-27·9), and the number needed to treat was 7 (95% CI 4-502). Iliofemoral patency after 6 months was reported in 58 patients (65·9%, 95% CI 55·5-75·0) on CDT versus 45 (47·4%, 37·6-57·3) on control (p=0·012). 20 bleeding complications related to CDT included three major and five clinically relevant bleeds.

INTERPRETATION

Additional CDT should be considered in patients with a high proximal DVT and low risk of bleeding.

FUNDING

South-Eastern Norway Regional Health Authority; Research Council of Norway; University of Oslo; Oslo University Hospital.

SEOM guidelines on thrombosis in cancer patients

The association between cancer and thrombosis is well established. Venous thromboembolism (VTE) is considered a main cause of mortality and morbidity in cancer patients and is commonly underestimated by oncologists. In recent years the incidence rates of VTE have notably increased. Several studies have clearly shown that cancer patients who are diagnosed with VTE present a poorer prognosis. The Spanish Society of Medical Oncology (SEOM) presents the guidelines for thrombosis and cancer in order to improve the prevention and management of VTE.

Pharmacomechanical Thrombolysis of Acute and Chronic Symptomatic Deep Vein Thrombosis: A Systematic Review of Literature

Pharmacomechanical thrombolysis (PMT) is an emerging treatment option for symptomatic deep vein thrombosis (DVT). This may obviate the need for systemic or catheter-directed thrombolysis. PubMed, EMBASE, and Cochrane database search of PMT in acute and chronic symptomatic DVT was undertaken. Baseline demographic and clinical characteristics, procedural details, DVT characteristics, and procedural and clinical outcomes are presented. A total of 8 case series (n = 2528; 1998-2009) qualified for inclusion. Lower extremity symptomatic DVTs constituted the majority of the cases (>80%). Both acute (<14 days) and chronic (>14 days) DVTs were included. Procedural success was 59% to 100% and catheter-directed thrombolysis was used as an adjunct in 16% to 53%. No deaths or major bleeding complications were reported. Pharmacomechanical thrombolysis leads to the immediate resolution of clinical symptoms of DVT in the majority of patients. Pharmacomechanical thrombolysis may be a safe and novel method, when appropriate expertise and resources are available, for the treatment of symptomatic acute and chronic DVT.

Management of deep vein thrombosis to reduce the incidence of post-thrombotic syndrome

The post-thrombotic syndrome (PTS) is the major chronic sequel of deep vein thrombosis (DVT) of the leg, and is a major socioeconomic challenge. In addition to systematic prophylaxis of DVT in hospitalized patients, effective management of DVT is important to reduce the incidence of PTS. Thrombolysis and thrombectomy are not indicated routinely. Optimal anticoagulation, usually with heparins initially and then with oral warfarin, is important to prevent recurrent DVT, which is a major risk factor for PTS. Following a routine three-month period of anticoagulation, patients with proximal idiopathic DVT should be individually assessed for the benefits and risks of continued oral anticoagulation, including patient preferences. Risk factors for recurrent DVT include active cancer, pregnancy, continued use of oral oestrogens, male sex, obesity, recurrent thrombosis, established PTS, permanent inferior vena caval filters, residual DVT, high fibrin d-dimer and other thrombophilias. Early walking, continued high levels of physical activity and wearing compression stockings for up to two years may also reduce the risk of PTS.

An update on etiology, prevention, and therapy of postthrombotic syndrome

Postthrombotic syndrome is a common sequelae resulting from deep venous thrombosis. The primary interventions are prevention and treatment, both of which many vascular specialists may not always recognize. We review the definition, epidemiology, the basic pathophysiology, and preventative management for postthrombotic syndrome. The current primary medical and interventional treatment modalities to decrease the occurrence of postthrombotic syndrome are also highlighted. Many of these treatments are currently available and simply need to be adhered to, whereas others are a shift in the paradigm, focusing on active thrombus removal.

Treatment and secondary prevention of venous thromboembolism in cancer

Patients with cancer who develop venous thromboembolism (VTE) are at elevated risk for recurrent thrombotic events, even during anticoagulant therapy. The clinical picture is further complicated because these patients are also at increased risk of bleeding while on anticoagulants. In general, there are four key goals of treatment for VTE: preventing fatal pulmonary embolism (PE); reducing short-term morbidities associated with acute leg or lung thrombus; preventing recurrent VTE; and preventing the long-term sequelae of VTE (e.g., post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension). A fifth goal – minimising the risk for bleeding while on anticoagulation – is particularly warranted in patients with cancer. Traditionally, pharmacological treatment of VTE has two phases, with the transition between phases marked by a switch from a rapid-acting, parenterally administered anticoagulant (such as unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), or fondaparinux) to an oral vitamin K antagonist (e.g., warfarin). Recent clinical trials of established agents and the advent of new pharmacological options are changing this paradigm. Low-molecular-weight heparin continued for 6 months is more effective than warfarin in the secondary prevention of VTE in cancer patients without increasing the risk of bleeding and is now the preferred treatment option. Given the impact of VTE on short-term and long-term outcomes in patients with cancer, a group of health-care providers based in the United Kingdom gathered in London in 2009 to discuss recent data on cancer-associated thrombosis and to evaluate how these recommendations can be integrated or translated into UK clinical practice. This article, which is the third of four articles covering key topics in cancer thrombosis, focuses on treatment and secondary prevention of VTE in cancer patients.

Individually tailored duration of elastic compression therapy in relation to incidence of the postthrombotic syndrome

OBJECTIVE

We assessed whether individualized shortened duration of elastic compression stocking (ECS) therapy after acute deep venous thrombosis (DVT) is feasible without increasing the incidence of postthrombotic syndrome (PTS).

METHODS

At the outpatient clinic of the Maastricht University Medical Centre, 125 consecutive patients with confirmed proximal DVT were followed for 2 years. Villalta scores were assessed on four consecutive visits; 3, 6, 12, and 24 months after the acute event. Reflux was assessed once by duplex testing. After 6 months, patients with scores <or=4 on the Villalta clinical score and in the absence of reflux were allowed to discontinue ECS therapy. If reflux was present, two consecutive scores <or=4 were needed to discontinue ECS therapy.

RESULTS

ECS therapy was discontinued in 17% of patients at 6 months, in 48% at 12 months, and in 50% at 24 months. Reflux on duplex testing was present in 74/101 (73.3%) tested patients and was not associated with the onset of PTS. At the 6-month visit, the cumulative incidence of PTS was 13.3%, at 12 months 17.0%, and at 24 months 21.1%. Varicosities/venous insufficiency (present at baseline) was significantly associated with PTS; hazard ratio 3.2 (1.2-9.1).

CONCLUSIONS

Patients with a low probability for developing PTS can be identified as early as 6 months after the thrombotic event, and individualized shortened duration of ECS therapy based on Villalta clinical scores may be a safe management option. These findings need to be confirmed in a randomized clinical trial.