How I treat the postthrombotic syndrome

American Society of Hematology 2020 guidelines for management of venous thromboembolism: treatment of deep vein thrombosis and pulmonary embolism

BACKGROUND

Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), occurs in ∼1 to 2 individuals per 1000 each year, corresponding to ∼300 000 to 600 000 events in the United States annually.

OBJECTIVE

These evidence-based guidelines from the American Society of Hematology (ASH) intend to support patients, clinicians, and others in decisions about treatment of VTE.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and adult patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 28 recommendations for the initial management of VTE, primary treatment, secondary prevention, and treatment of recurrent VTE events.

CONCLUSIONS

Strong recommendations include the use of thrombolytic therapy for patients with PE and hemodynamic compromise, use of an international normalized ratio (INR) range of 2.0 to 3.0 over a lower INR range for patients with VTE who use a vitamin K antagonist (VKA) for secondary prevention, and use of indefinite anticoagulation for patients with recurrent unprovoked VTE. Conditional recommendations include the preference for home treatment over hospital-based treatment for uncomplicated DVT and PE at low risk for complications and a preference for direct oral anticoagulants over VKA for primary treatment of VTE.

von Willebrand Factor Is a Critical Mediator of Deep Vein Thrombosis in a Mouse Model of Diet-Induced Obesity

OBJECTIVE

Obesity is characterized by chronic low-grade inflammation and consequentially a hypercoagulable state, associating with an increased incidence of venous thromboembolism. Increased VWF (von Willebrand factor) plasma concentration and procoagulant function are independent risk factors for venous thromboembolism and are elevated in obese patients. Here, we explore the pathobiological role of VWF in obesity-associated venous thrombosis using murine models. Approach and Results: We first showed that diet-induced obese mice have increased VWF plasma levels and FVIII (factor VIII) activity compared with littermate controls. Elevated VWF levels appeared to be because of both increased synthesis and impaired clearance. Diet-induced obesity-associated venous thrombosis was assessed using the inferior vena cava-stenosis model of deep vein thrombosis. Diet-induced obese mice developed larger venous thrombi that were rich in VWF, erythrocytes, and leukocytes. Administering a polyclonal anti-VWF antibody or an anti-VWF A1 domain nanobody was protective against obesity-mediated thrombogenicity. Delayed administration (3 hours post-inferior vena cava stenosis) similarly reduced thrombus weight in diet-induced obese mice.

CONCLUSIONS

This study demonstrates the critical role of VWF in the complex, thrombo-inflammatory state of obesity. It adds to the growing rationale for targeting VWF-specific interactions in thrombotic disease.

A magnetically modified black phosphorus nanosheet-based heparin delivery platform for preventing DVT accurately

A new heparin targeting delivery platform was developed based on iron oxide (Fe3O4) nanoparticles and polyethyleneimine (PEI) functionalized black phosphorus nanosheets (BP NSs). Both in and ex vivo studies suggested that this drug delivery platform (PEI/Fe3O4@BP NSs) possessed high heparin loading capacity (≈450%), accurate magnetic enrichment capacity, and good biocompatibility. With the aid of near-infrared (NIR) laser irradiation, this BP NS based delivery platform could further enhance the photothermal thrombolysis effect. Most importantly, the experiments in vivo confirmed that the proposed PEI/Fe3O4@BP NSs could considerably prolong the effective drug concentration duration of heparin. By which means, accurate, long-acting, and effective thromboprophylaxis could be accomplished with limited drug dosage, which could radically reduce the perniciousness of drug overdose.

Long-term treatment of venous thromboembolism

The most important decision in the long-term treatment of venous thromboembolism (VTE) is how long to anticoagulate. VTE provoked by a reversible risk factor, or a first unprovoked isolated distal deep vein thrombosis (DVT), generally should be treated for 3 months. VTE provoked by a persistent or progressive risk factor (eg, cancer), or a second unprovoked proximal DVT or PE, is generally treated indefinitely. First unprovoked proximal DVT or PE may be treated for 3 to 6 months or indefinitely. Male sex, presentation as PE (particularly if concomitant proximal DVT), a positive d-dimer test after stopping anticoagulation, an antiphospholipid antibody, low risk of bleeding, and patient preference favor indefinite anticoagulation. The type of indefinite anticoagulation is of secondary importance. Low-dose oral Xa inhibitors are convenient and are thought to have a lower risk of bleeding; they are less suitable if there is a higher risk for recurrence. For cancer-associated VTE, we now prefer full-dose oral Xa inhibitors over low-molecular-weight heparin, with gastrointestinal lesions being a relative contraindication. Graduated compression stockings are not routinely indicated after DVT, but are encouraged if there is persistent leg swelling or if a trial of stockings improves symptoms. Medications have a limited role in the treatment of postthrombotic syndrome. After PE, patients should have clinical surveillance for chronic thromboembolic pulmonary hypertension (CTEPH), with ventilation-perfusion scanning and echocardiography being the initial diagnostic tests if CTEPH is a concern. Patients with CTEPH and other symptomatic patients with extensive residual perfusion defects should be evaluated for endarterectomy, balloon pulmonary angioplasty, or vasodilator therapies.

External validation of the SOX-PTS score in a prospective multicenter trial of patients with proximal deep vein thrombosis

BACKGROUND

Using data from the SOX Trial, we recently developed a clinical prediction model for occurrence of the postthrombotic syndrome (PTS) after proximal deep vein thrombosis (DVT), termed the SOX-PTS score. The score includes anatomical extent of DVT; body mass index; and baseline Villalta score.

OBJECTIVE

To externally validate the SOX-PTS score.

METHODS

Logistic regression analysis of data from the ATTRACT Trial that evaluated pharmacomechanical catheter directed thrombolysis in patients with proximal DVT. The primary outcome was the occurrence of PTS (defined as Villalta score ≥ 5) from 6 to 24 months after DVT. Secondary outcomes included moderate-severe PTS (Villalta scale ≥ 10) and severe PTS (Villalta scale ≥ 14). Predictive performance was assessed by discrimination and calibration. An updated score was evaluated in an exploratory analysis.

RESULTS

Six hundred and ninety-one ATTRACT patients were included, of whom 328 (47%) developed PTS. The c-statistic was 0.63; 95% confidence interval (CI) 0.59-0.67 for PTS. The model's performance appeared to be better for the outcomes moderate to severe PTS and severe PTS (c-statistic 0.67; 95% CI 0.62-0.72 for moderate-severe PTS and 0.70; 0.64-0.77 for severe PTS). An updated model with age as an additional variable performed similarly to the original model.

CONCLUSION

We externally validated the SOX-PTS score for estimating the risk of developing PTS, moderate to severe PTS, and severe PTS, in patients with proximal DVT. The score may be useful to predict PTS at the time of DVT diagnosis. Further external validation in different patient cohorts is required.

Long-term risk of postthrombotic syndrome after symptomatic distal deep vein thrombosis: The CACTUS-PTS study

BACKGROUND

After a proximal lower limb deep vein thrombosis (DVT; involving popliteal veins or above), up to 40% of patients develop postthrombotic syndrome (PTS) as assessed by the Villalta scale (VS). Poor initial anticoagulant treatment is a known risk factor for PTS. The risk of developing PTS after isolated distal DVT (infra-popliteal DVT without pulmonary embolism), and the impact of anticoagulant treatment on this risk, are uncertain.

METHODS

Long-term follow-up of CACTUS double-blind trial comparing 6 weeks of s.c. nadroparin (171 IU/kg/d) versus s.c. placebo for a first symptomatic isolated distal DVT. At least 1 year after randomization, patients had a PTS assessment in clinic or by phone using the VS.

RESULTS

After a median follow-up of 6 years, PTS was present in 30% (n = 54) of the 178 patients who had a PTS assessment. PTS was moderate or severe in 24% (n = 13) of cases. There was no statistically significant difference in prevalence of PTS in the nadroparin versus placebo groups (29% versus 32%, P = .6), except in patients without evidence of primary chronic venous insufficiency (9% versus 24%, P = .04). Rates of venous thromboembolism recurrence during follow-up in the nadroparin and placebo groups were, respectively, 8% (n = 7) and 14% (n = 13; P = .2).

CONCLUSION

After a first isolated distal DVT, the risk of PTS is substantial but much lower than that reported after proximal DVT. Anticoagulation with nadroparin doesn't provide any clear benefit to prevent PTS, except in patients without preexisting chronic venous insufficiency. Anticoagulation might be associated with a lower risk of venous thromboembolism recurrence.

The risk of post-thrombotic syndrome in patients with proximal deep vein thrombosis treated with the direct oral anticoagulants

The novel direct oral anticoagulants (DOAC) have been shown to be at least as effective as and safer than conventional anticoagulants for the initial and long-term treatment of venous thromboembolic disorders. However, the rate of post-thrombotic syndrome (PTS) in patients with deep-vein thrombosis (DVT) treated with the DOACs is unknown. With the adoption of the Villalta scale, we assessed the rate of PTS at the end of the follow-up period in a consecutive series of 309 outpatients with acute proximal DVT who had received at least 3 months of treatment with a DOAC and had been followed-up for up to 3 years. The rate of PTS development was compared with that recorded in a historical cohort of 1036 consecutive patients who had been treated with vitamin K antagonists (VKA) and had received a similar follow-up examination. Logistic regression analysis, including propensity scoring to adjust for differing probabilities of undergoing VKA/DOAC, was used to identify predictors of PTS. PTS developed in 87 patients (28.2%) treated with the DOACs (severe in 12), and in 443 patients (42.8%) treated with VKAs (severe in 61). After adjusting for estimated propensity score, age, gender, concomitant symptoms of pulmonary embolism, duration of anticoagulation and development of residual vein thrombosis, the risk of PTS in the DOAC-treated patients was reduced by 54% in comparison to patients treated with conventional anticoagulation (odds ratio 0.46; 95% CI 0.33 to 0.63). We conclude that in comparison to VKAs, the use of the direct oral anticoagulants has the potential to offer a more favorable prognosis in terms of PTS development.

Prevention and Management of the Post-Thrombotic Syndrome

The post-thrombotic syndrome (PTS) is a form of chronic venous insufficiency secondary to prior deep vein thrombosis (DVT). It affects up to 50% of patients after proximal DVT. There is no effective treatment of established PTS and its management lies in its prevention after DVT. Optimal anticoagulation is key for PTS prevention. Among anticoagulants, low-molecular-weight heparins have anti-inflammatory properties, and have a particularly attractive profile. Elastic compression stockings (ECS) may be helpful for treating acute DVT symptoms but their benefits for PTS prevention are debated. Catheter-directed techniques reduce acute DVT symptoms and might reduce the risk of moderate-severe PTS in the long term in patients with ilio-femoral DVT at low risk of bleeding. Statins may decrease the risk of PTS, but current evidence is lacking. Treatment of PTS is based on the use of ECS and lifestyle measures such as leg elevation, weight loss and exercise. Venoactive medications may be helpful and research is ongoing. Interventional techniques to treat PTS should be reserved for highly selected patients with chronic iliac obstruction or greater saphenous vein reflux, but have not yet been assessed by robust clinical trials.

Intervention for Iliofemoral Deep Vein Thrombosis and May-Thurner Syndrome

May-Thurner syndrome, also known as iliac vein compression syndrome, may cause symptoms of venous hypertension and is a predisposing factor for the development of iliofemoral deep vein thrombosis (DVT). Iliofemoral DVT is associated with high rates of development of postthrombotic syndrome, a potentially debilitating condition associated with development of symptoms related to venous outflow obstruction and resulting in reduced quality of life. In this Clinics article, we review procedural intervention with catheter-directed thrombolysis and stenting for iliofemoral DVT and iliac vein compression.

Resolvin D4 attenuates the severity of pathological thrombosis in mice

Deep vein thrombosis (DVT) is a common cardiovascular disease with a major effect on quality of life, and safe and effective therapeutic measures to efficiently reduce existent thrombus burden are scarce. Using a comprehensive targeted liquid chromatography-tandem mass spectrometry-based metabololipidomics approach, we established temporal clusters of endogenously biosynthesized specialized proresolving mediators (SPMs) and proinflammatory and prothrombotic lipid mediators during DVT progression in mice. Administration of resolvin D4 (RvD4), an SPM that was enriched at the natural onset of thrombus resolution, significantly reduced thrombus burden, with significantly less neutrophil infiltration and more proresolving monocytes in the thrombus, as well as an increased number of cells in an early apoptosis state. Moreover, RvD4 promoted the biosynthesis of other D-series resolvins involved in facilitating resolution of inflammation. Neutrophils from RvD4-treated mice were less susceptible to an ionomycin-induced release of neutrophil extracellular traps (NETs), a meshwork of decondensed chromatin lined with histones and neutrophil proteins critical for DVT development. These results suggest that delivery of SPMs, specifically RvD4, modulates the severity of thrombo-inflammatory disease in vivo and improves thrombus resolution.

Quality of life after pharmacomechanical catheter-directed thrombolysis for proximal deep venous thrombosis

BACKGROUND

After deep venous thrombosis (DVT), many patients have impaired quality of life (QOL). We aimed to assess whether pharmacomechanical catheter-directed thrombolysis (PCDT) improves short-term or long-term QOL in patients with proximal DVT and whether QOL is related to extent of DVT.

METHODS

The Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-Directed Thrombolysis (ATTRACT) trial was an assessor-blinded randomized trial that compared PCDT with no PCDT in patients with DVT of the femoral, common femoral, or iliac veins. QOL was assessed at baseline and 1 month, 6 months, 12 months, 18 months, and 24 months using the Venous Insufficiency Epidemiological and Economic Study on Quality of Life/Symptoms (VEINES-QOL/Sym) disease-specific QOL measure and the 36-Item Short Form Health Survey (SF-36) physical component summary (PCS) and mental component summary general QOL measures. Change in QOL scores from baseline to assessment time were compared in the PCDT and no PCDT treatment groups overall and in the iliofemoral DVT and femoral-popliteal DVT subgroups.

RESULTS

Of 692 ATTRACT patients, 691 were analyzed (mean age, 53 years; 62% male; 57% iliofemoral DVT). VEINES-QOL change scores were greater (ie, better) in PCDT vs no PCDT from baseline to 1 month (difference, 5.7; P = .0006) and from baseline to 6 months (5.1; P = .0029) but not for other intervals. SF-36 PCS change scores were greater in PCDT vs no PCDT from baseline to 1 month (difference, 2.4; P = .01) but not for other intervals. Among iliofemoral DVT patients, VEINES-QOL change scores from baseline to all assessments were greater in the PCDT vs no PCDT group; this was statistically significant in the intention-to-treat analysis at 1 month (difference, 10.0; P < .0001) and 6 months (8.8; P < .0001) and in the per-protocol analysis at 18 months (difference, 5.8; P = .0086) and 24 months (difference, 6.6; P = .0067). SF-36 PCS change scores were greater in PCDT vs no PCDT from baseline to 1 month (difference, 3.2; P = .0010) but not for other intervals. In contrast, in femoral-popliteal DVT patients, change scores from baseline to all assessments were similar in the PCDT and no PCDT groups.

CONCLUSIONS

Among patients with proximal DVT, PCDT leads to greater improvement in disease-specific QOL than no PCDT at 1 month and 6 months but not later. In patients with iliofemoral DVT, PCDT led to greater improvement in disease-specific QOL during 24 months.

Risk of recurrent venous thromboembolism after acute pulmonary embolism: Role of residual pulmonary obstruction and persistent right ventricular dysfunction. A meta-analysis

Essentials Debated is the role of residual pulmonary obstruction (RPO) in predicting venous thromboembolism. Whether right ventricular dysfunction (RVD) predicts recurrent venous thromboembolism is unknown. 15 studies on RPO and 4 on RVD and venous thromboembolism were included in this meta-analysis. RPO is a predictor of recurrent venous thromboembolism when assessed by perfusion lung scan. RVD after acute pulmonary embolism is not associated with recurrent venous thromboembolism.

BACKGROUND

There is conflicting evidence regarding the role of residual pulmonary obstruction (RPO) or persistent right ventricular dysfunction (RVD) after pulmonary embolism (PE) as a predictor of recurrent venous thromboembolism (VTE). The aim of this study was to assess whether RPO or persistent RVD after PE is associated with recurrent VTE.

METHODS

MEDLINE and EMBASE were searched through December 2018. Studies reporting on (a) RPO either on computed tomography (CT) angiography or perfusion lung scan, or RVD on echocardiography or CT angiography, after therapeutic anticoagulation for the acute PE, and (b) recurrent VTE, were included in this meta-analysis.

RESULTS

RPO was associated with an increased risk of recurrent VTE (16 studies; 3472 patients; odds ratio [OR] 2.22; 95% confidence interval [CI] 1.61-3.05; I2  = 26%); the association was statistically significant for lung scan-detected RPO (11 studies; 2916 patients; OR 2.21; 95% CI 1.63-3.01) but not for CT angiography-detected RPO (five studies; 556 patients; OR 2.56; 95% CI 0.82-7.94). No significant association was found between persistent RVD and recurrent VTE (four studies; 852 patients; OR 1.62; 95% CI 0.63-4.17).

CONCLUSIONS

RPO is a predictor of recurrent VTE after a first acute PE, mainly when assessed by perfusion lung scan.

Measuring functional limitations after venous thromboembolism: A call to action

The main objectives of therapeutic trials in venous thromboembolism (VTE) are to prevent recurrent VTE, major bleeding and death. While these outcomes are indeed highly relevant, they are also rare and do not fully capture the overall functional outcome of VTE patients. Importantly, functional limitations after VTE are prevalent after both deep vein thrombosis and pulmonary embolism occurring in up to 50% of patients. These post-VTE syndromes are associated with a decreased quality of life, higher risk of depressive disorders, unemployment and increased utilization of healthcare resources. Because of the major impact of functional limitations on individual patients and society as a whole, development of tools able to capture functional outcomes in clinical trials are urgently needed. We anticipate that a standardized post-VTE functional status scale will aid in demarcating effective and ineffective VTE therapies on functional outcomes in trials with appropriately powered sample sizes, as well as pave the road for value-based healthcare. The scale that we have in mind covers the entire spectrum of functional outcomes ranging from no symptoms to death. Moreover, it focuses on both limitations in usual activity as well as changes in lifestyle. The scale is not meant to replace current diagnostic or prognostic scores for post-VTE syndromes, but to be used as an outcome measure to evaluate the overall consequences of VTE on functional status. This review is a call for action to the VTE community to join forces and support further development of the proposed scale, a process of which we summarize the necessary steps.

Incidence and Risk Factors for Post-Thrombotic Syndrome in Patients With Deep Vein Thrombosis Following Total Knee and Hip Arthroplasty

BACKGROUND

Deep vein thrombosis (DVT) is common after total joint arthroplasty (TJA), and can cause the sequela of post-thrombotic syndrome (PTS), which is associated with decreased quality of life and increased treatment cost. The purpose of this study is to determine the incidence and risk factors for PTS in patients with DVT following primary unilateral total knee and hip arthroplasty.

METHODS

We conducted this follow-up study involving patients developing DVT after primary unilateral total knee arthroplasty or total hip arthroplasty at our institution between April 2010 and March 2017. Each patient received a follow-up clinical interview regarding PTS-related symptoms and signs. We introduced demographic, clinical, and surgical data into the analysis to identify the risk factors for PTS.

RESULTS

A total of 182 patients with postoperative DVT were enrolled with a mean follow-up time of 3.6 years. The incidence of PTS was 9.3% in patients developing DVT after TJA. Malignancy (P = .033), previous surgery in ipsilateral lower extremity (P = .013), and blood transfusion (P = .022) appeared to be the risk factors for PTS.

CONCLUSION

We determined the incidence and risk factors for PTS in patients with DVT following TJA. Preventive measures should be used for patients at high risk of PTS.

Management and treatment of deep vein thrombosis in special populations

INTRODUCTION

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is the third most frequent cardiovascular disease besides myocardial infarction and stroke. Because DVT may cause life-threatening conditions, treatment should be started as soon as possible. This comprises certain challenges in special populations. Areas covered: In cancer-associated VTE, current treatment is different from non-cancer VTE due to disease-related interventions and higher bleeding risks. In the treatment of patients with extensive DVT, the role of catheter-directed thrombolysis has been investigated in two randomized trials, but results do not yield a recommendation for standard thrombolysis. The diagnosis of suspected recurrent DVT is especially challenging in case of ipsilateral DVT. Treatment strategies in recurrent DVT are dependent on the case and on particular risk factors. Also discussed is the therapy for DVT in pregnant women, which is more complex as a result of anticoagulants crossing the placenta. Expert commentary: DVT treatment in special populations poses special challenges due to high thrombotic and bleeding risk. This will be discussed in more detail in this review.