Long-term treatment of deep venous thrombosis with a low molecular weight heparin (tinzaparin): a prospective randomized trial

Modest response in translation to home management of deep venous thrombosis

BACKGROUND

years may elapse between the publication of results of rigorous randomized trials and changes in clinical practice. It is not often that a definitive time interval can be identified that shows the time taken for published clinical trials to affect clinical practice. In the present study, we track the timelines of evidence for home treatment of deep venous thrombosis and its eventual impact on hospitalizations and early discharge.

METHODS

the number of patients discharged from short-stay hospitals throughout the United States between 1979 and 2006 with a principal diagnosis of deep venous thrombosis and the proportion discharged in ≤ 2 days was determined from The National Hospital Discharge Survey. We also attempted to identify all published articles that reported home treatment of deep venous thrombosis in unselected populations.

RESULTS

eleven years after demonstration of the safety and efficacy of home treatment, there was only a 21% decrease in the population-based incidence of hospitalizations of patients with a principal diagnosis of deep venous thrombosis. The proportion of patients with a principal diagnosis of deep venous thrombosis who were discharged in ≤ 2 days began to increase prominently after the 1996 publication of trials showing the safety and efficacy of home treatment, and continued to increase through 2006. However, the proportion discharged early remained modest (21% to 25%).

CONCLUSIONS

whether the slow implementation of home treatment reflects a cautious approach accompanied by a gradual testing of shortened hospitalization for deep venous thrombosis or other factors is uncertain.

Incidence of arterial cardiovascular events after venous thromboembolism: a systematic review and a meta-analysis

SUMMARY BACKGROUND

Whether patients with unprovoked venous thromboembolism (VTE) have a higher risk of arterial cardiovascular events than the general population and patients with provoked VTE is a matter of debate.

OBJECTIVE

To perform a systematic review and a meta-analysis aimed at assessing the risk of arterial cardiovascular events in patients with unprovoked VTE as compared with both patients with provoked VTE and controls.

METHODS

A systematic search was performed. Studies reporting on (i) patients with confirmed VTE, (ii) a follow-up of at least 6 months and (iii) the incidence of arterial cardiovascular events (acute myocardial infarction and ischemic stroke) were included in the systematic review. Those studies reporting separate incidences of cardiovascular events in patients with unprovoked and provoked VTE or patients with unprovoked VTE and controls were included in the incidence rate meta-analysis.

RESULTS

Overall, 17 studies were included in the systematic review. The weighted mean incidence of arterial cardiovascular events was 0.46% [95% confidence interval (CI) 0.34-0.59] and 0.35% (95% CI 0.24-0.49) per patient-year in patients with unprovoked and provoked VTE, respectively. Six studies were included in the meta-analysis. The risk of arterial cardiovascular events appeared to be higher in patients with unprovoked VTE than in controls [incidence rate ratio (IRR) 1.87, 95% CI 1.32-2.65] and than in patients with provoked VTE (IRR 1.86, 95% CI 1.19-2.89).

CONCLUSIONS

Patients with unprovoked VTE have a higher risk of arterial cardiovascular events than patients with provoked VTE over long-term follow-up.

Home therapy of venous thrombosis with long-term LMWH versus usual care: patient satisfaction and post-thrombotic syndrome

PURPOSE

Home-LITE compared long-term treatment at home with tinzaparin or usual care in terms of efficacy, safety, patients' treatment satisfaction, incidence of post-thrombotic syndrome, and associated venous leg ulcers.

METHODS

This multicenter, randomized, controlled trial enrolled 480 patients with documented, acute, proximal deep vein thrombosis. Patients received tinzaparin 175 IU/kg subcutaneously once daily for 12 weeks, or tinzaparin for >or=5 days plus oral warfarin, commenced on day 1, international normalized ratio-adjusted, and continued for >or=12 weeks ("usual care"). Patients received 1 in-clinic injection, then home treatment.

RESULTS

The rate of recurrent venous thromboembolism at 12 weeks was 3.3% in both groups (absolute difference 0%; 95% confidence interval -3.2-3.2), and at 1 year was 10.4%/8.3% in the tinzaparin/usual-care groups, respectively (difference 2.1%; 95% confidence interval -3.1-7.3). There were no between-group differences in deaths at 12 weeks or 1 year, or bleeding at 12 weeks. Patients in the tinzaparin group expressed significantly greater treatment satisfaction (P = .0024), particularly regarding freedom from the inconvenience of blood monitoring; were less likely to report signs/symptoms of post-thrombotic syndrome (individual odds ratios 0.66 to 0.91, overall odds ratio 0.77, P = .001); and reported fewer leg ulcers at 12 weeks: 1 (0.5%) versus 8 (4.1%) (P = .02) with usual care.

CONCLUSIONS

Long-term home treatment with tinzaparin or usual care resulted in similar rates of recurrent venous thromboembolism, death, and bleeding. The significantly lower incidence of post-thrombotic syndrome and leg ulcers observed in the tinzaparin group is a potentially important benefit and deserves further study.

Long-term Intervention with Heparins in a Rat Model of Peritoneal Dialysis

Background

Peritoneal dialysis (PD) is associated with functional and structural alterations of the peritoneal membrane, particularly new vessel formation and fibrosis. In addition to anticoagulant effects, heparin displays anti-inflammatory and angiostatic properties. Therefore, the effects of administration of heparins on function and morphology of the peritoneal membrane were studied in a rat PD model.

Methods

Rats received 10 mL conventional PD fluid (PDF) daily, with or without the addition of unfractionated heparin (UFH) or low molecular weight heparin (LMWH) in the PDF (1 mg/10 mL intraperitoneally) via a mini access port. Untreated rats served as controls. After 5 weeks, a 90-minute functional peritoneal transport test was performed and tissues and peritoneal leukocytes were taken.

Results

PD treatment induced loss of ultrafiltration ( p < 0.01), a twofold increase in glucose absorption ( p < 0.03), increased urea transport ( p < 0.02), and loss of sodium sieving ( p < 0.03), which were also found in the PDF + heparin groups. Increased peritoneal cell influx and hyaluronan production ( p < 0.02) as well as an exchange of mast cells and eosinophils for neutrophils after PD treatment were observed in PD rats; addition of heparin did not affect those changes. Mesothelial regeneration, submesothelial blood vessel and matrix formation, and accumulation of tissue macrophages were seen in PD animals. Spindle-shaped vimentin-positive and cytokeratin-negative cells indicated either partial injury and denudation of mesothelial cells or epithelial-to-mesenchymal transition. Neither UFH nor LMWH affected any of these morphological changes.

Conclusion

Within 5 weeks, PD treatment induces a chronic inflammatory condition in the peritoneum, evidenced by high transport, leukocyte recruitment, tissue remodeling, and induction of spindle-shaped cells in the mesothelium. Addition of LMWH or UFH to the PDF did not prevent these adverse PDF-induced peritoneal changes.

Low-molecular-weight heparins are superior to vitamin K antagonists for the long term treatment of venous thromboembolism in patients with cancer: a cochrane systematic review

Background

Cancer and its therapies increase the risk of venous thromboembolism. Compared to patients without cancer, patients with cancer anticoagulated for venous thromboembolism are more likely to develop recurrent thrombotic events and major bleeding. Addressing all important outcomes including harm is of great importance to make evidence based health care decisions. The objective of this study was to compare low molecular weight heparin (LMWH) and oral anticoagulants (vitamin K antagonist (VKA) and ximelagatran) for the long term treatment of venous thromboembolism in patients with cancer.

Methods

A systematic review of the medical literature. We followed the Cochrane Collaboration methodology for conducting systematic reviews. We assessed methodological quality for each outcome by grading the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology.

Results

Eight randomized controlled trials (RCTs) were eligible and reported data for patients with cancer. The quality of evidence was low for death and moderate for recurrent venous thromboembolism. LMWH, compared to VKA provided no statistically significant survival benefit (Hazard ratio (HR) = 0.96; 95% CI 0.81 to 1.14) but a statistically significant reduction in venous thromboembolism (HR = 0.47; 95% (Confidence Interval (CI) = 0.32 to 0.71). There was no statistically significant difference between LMWH and VKA in bleeding outcomes (RR = 0.91; 95% CI = 0.64 to 1.31) or thrombocytopenia (RR = 1.02; 95% CI = 0.60 to 1.74).

Conclusion

For the long term treatment of venous thromboembolism in patients with cancer, LMWH compared to VKA reduces venous thromboembolism but not death.

Anticoagulation for the long term treatment of venous thromboembolism in patients with cancer

BACKGROUND

Cancer increases the risk of thromboembolic events and the risk of recurrent thromboembolic events while on anticoagulation.

OBJECTIVES

To compare the efficacy and safety of low molecular weight heparin (LMWH) and oral anticoagulants (vitamin K antagonist (VKA) and ximelagatran) for the long term treatment of venous thromboembolism (VTE) in patients with cancer.

SEARCH STRATEGY

A comprehensive search was undertaken including a January 2007 search of electronic databases; Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library 2007, Issue 1). MEDLINE (1966 onwards; accessed via OVID), EMBASE (1980 onwards; accessed via OVID) and ISI the Web of Science. Hand search of the proceedings of the American Society of Clinical Oncology and of the American Society of Hematology. Checking of references of included studies, relevant papers and related systematic reviews. Use of "related article" feature in PubMed; and (5) search of ISI the Web of Science for papers citing landmark studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing long term treatment with LMWH versus oral anticoagulants (VKA or ximelagatran) in patients with cancer and symptomatic objectively confirmed VTE.

DATA COLLECTION AND ANALYSIS

Using a standardized data form we extracted data on methodological quality, participants, interventions and outcomes of interest: survival, recurrent VTE, major bleeding, minor bleeding, thrombocytopenia and postphlebitic syndrome.

MAIN RESULTS

Of 3986 identified citations, eight RCTs were eligible and reported data for patients with cancer. Their overall methodological quality was moderate. Meta-analysis of six RCTs showed that LMWH, compared to VKA provided no statistically significant survival benefit (Hazard ratio (HR) = 0.96; 95% CI 0.81 to 1.14) but a statistically significant reduction in VTE (HR = 0.47; 95% (Confidence Interval (CI) = 0.32 to 0.71). There was no statistically significant difference between LMWH and VKA in bleeding outcomes (RR = 0.91; 95% CI = 0.64 to 1.31) or thrombocytopenia (RR = 1.02; 95% CI = 0.60 to 1.74). One RCT compared tinzaparin and dalteparin and showed no differences in the outcomes of interest. One RCT compared a six months extension of anticoagulation with 18 months Ximelagatran 24mg twice daily versus placebo. It showed a reduction in VTE (HR = 0.16; 95% CI 0.09 to 0.30) with no apparent effect on survival or bleeding.

AUTHORS' CONCLUSIONS

For the long term treatment of VTE in patients with cancer, LMWH compared to VKA reduces venous thromboembolic events but not death. The decision for a patient with cancer and VTE to start long term LMWH versus oral anticoagulation should balance the benefits and downsides and integrate the patient's values and preferences for the important outcomes and alternative management strategies.

Home versus in-patient treatment for deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) occurs when a blood clot blocks blood flow through a vein. This can happen after surgery, trauma, or when a person has been immobile. Clots can dislodge and block blood flow to the lungs, causing death. Heparin is a blood-thinning drug used in the first 3-5 days of DVT treatment. Low molecular weight heparins (LMWH) allow people with DVT to receive their initial treatment at home instead of in hospital.

OBJECTIVES

To collate randomised controlled trials (RCTs) comparing home (LMWH) versus hospital (LMWH or UH) treatment for DVT, and to compare the safety, efficacy, acceptability and cost implications of home versus hospital treatment.

SEARCH STRATEGY

We searched the Cochrane Peripheral Vascular Diseases Group trials register (inception to May 2007) and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (last searched Issue 2, 2007) which includes searches of MEDLINE (January 1966 onwards) and EMBASE (January 1980 onwards). We also handsearched non-listed journals and contacted researchers in the field.

SELECTION CRITERIA

RCTs of home versus hospital treatment for DVT in which DVT was clinically confirmed and treated with either LMWH or UH.

DATA COLLECTION AND ANALYSIS

One reviewer selected the material for inclusion and another reviewed the literature and selection of trials. Two reviewers independently extracted data. Outcomes included PE, recurrent DVT, gangrene, heparin complications, and death.

MAIN RESULTS

Six RCTs involving 1708 participants with comparable treatment arms were included. All six had fundamental problems including high exclusion rates, partial hospital treatment of many in the LMWH arms, and comparison of UH in hospital with LMWH at home. The trials showed that patients treated at home with LMWH are less likely to have recurrence of venous thromboembolism (VTE) compared to hospital treatment with UH or LMWH (fixed effect relative risk (FE RR) 0.61; 95% confidence interval (CI) 0.42 to 0.90). Home treated patients also had lower mortality (FE RR 0.72; 95% CI 0.45 to 1.15) and fewer major bleeding (FE RR 0.67; 95% CI 0.33 to 1.36), but were more likely to have minor bleeding than those in hospital (FE RR 1.29; 95% CI 0.94 to 1.78) though these were not statistically significant.

AUTHORS' CONCLUSIONS

The limited evidence suggests that home management is cost effective and preferred by patients. Further large trials comparing these treatments are unlikely to occur. Therefore, home treatment is likely to become the norm; further research will be directed to resolving practical issues.

Latest medical treatment strategies for venous thromboembolism

Anticoagulant therapy with unfractionated heparin (UFH) followed by warfarin prevents thrombus extension, reduces the risk of recurrent thrombosis and prevents death in patients with venous thromboembolism (VTE). Low-molecular-weight heparin (LMWH) has replaced UFH as the preferred initial anticoagulant therapy for VTE because it is as effective and safe as UFH, but does not require laboratory monitoring and is less likely to cause immune thrombocytopenia and osteoporosis. More recently, fondaparinux has been shown to be an effective and safe alternative to LMWH and several new parenteral anticoagulants are being evaluated. The most important unmet need in the anticoagulant management of VTE is a replacement for warfarin. New oral anticoagulants that selectively target individual steps in the coagulation cascade have been shown to be effective for the long-term treatment of VTE in Phase II and III trials and are likely to become available in the near future.