MAIDSTONE AND TUNBRIDGE WELLS NHS TRUST



MAIDSTONE AND TUNBRIDGE WELLS NHS TRUST

Venous Thromboembolism (VTE), diagnosis and management in adults policy and procedure

Target audience: All Trust clinical staff

Main authors: Consultant Haematologist

Contact details: extension no. 35694

VTE Lead Nurse

Contact details: extension no. 24238

Other contributors: Consultant Physicians – Acute Medicine

Executive lead: Medical Director

Directorate: Specialist Medicine

Speciality: General Medicine / Venous Thromboembolism (VTE)

Supersedes: Venous Thromboembolism (VTE), diagnosis and management in adults policy and procedure [Version 1.0: October 2013]

Venous Thromboembolism (VTE), diagnosis and management in adults policy and procedure [Version 1.1: April 2014]

Approved by: Thrombosis Committee, 9th March 2017

Ratified by: Policy Ratification Committee, 15th June 2017

Review date: June 2020

Disclaimer: Printed copies of this document may not be the most recent version.

The master copy is held on Q-Pulse Document Management System

This copy – REV2.0

Document history

|Requirement for |To ensure that evidence based practice is undertaken for the diagnosis and management of adults with suspected venous |

|document: |thromboembolism. |

|Cross references |NICE guidance CG 144 (June 2012, updated November 2015): Venous thromboembolic diseases: the management of venous |

|(external): |thromboembolic diseases and the role of thrombophilia testing |

| |Study of bioaccumulation of Dalteparin at a therapeutic dose in patients with renal insufficiency. Schmid P et al. |

| |Journal of Thrombosis and Haemostasis. 2009 |

| |Reversal of Rivaroxaban and Dabigatran by Prothrombin complex concentrate: a randomized, placebo-controlled, crossover |

| |study in healthy subjects. Eerenberg ES et al. Circulation. October 2011 |

| |Prognostic value of echocardiography and spiral computed tomography in patients with pulmonary embolism. Gibson NS et al |

| |Current Opinion in Pulmonary Medicine. 2005 |

| |Risk factors for chronic thromboembolic pulmonary hypertension. N.H. Kim and I.M. Lang. European Respiratory Review March|

| |2012. |

| |Pulmonary Embolism; One-Year Follow-Up With Echocardiography Doppler and Five-Year Survival Analysis. Ary Ribeiro, MD, |

| |Per Lindmarker. Circulation. 1999. |

| |Scottish Intercollegiate Guidelines Network (SIGN) 122. Prevention and management of VTE. Dec 2010. |

| |British Thoracic Society (BTS) guidelines for management of suspected acute PE. 2003. |

| |Othieno R, Abu AM, Okpo E. Home versus in-patient treatment for deep vein thrombosis. Othieno R et al. Home versus |

| |in-patient treatment for deep vein thrombosis. Cochrane Database of Systematic Reviews: Reviews 2007. |

| |Trujillo-Santos J et al. Predicting adverse outcome in outpatients with acute deep vein thrombosis. Findings from the |

| |RIETE Registry. Journal of Vascular Surgery 2006. |

| |Anderson CM et al. Ambulation after deep vein thrombosis: a systematic review. Physiotherapy Canada. 2009;61(3):133 |

| |Outpatient versus inpatient treatment for patients with acute pulmonary embolism: an international, open-label, |

| |randomised, non-inferiority trial. Aujesky et al. The Lancet. 2011; 378(9785):41. |

| |Simplification of the pulmonary embolism severity index for prognostication in patients with acute symptomatic pulmonary |

| |embolism. Jiménez et al. RIETE Investigators. Archives of Internal Medicine. 2010; 170(15):1383. |

| |Rivaroxaban for the treatment of deep vein thrombosis and prevention of recurrent deep vein thrombosis and pulmonary |

| |Embolism. Issued: July 2012 NICE technology appraisal guidance 261 |

|Associated documents |Venous thromboembolism prevention policy and procedure [RWF-OPPPCSS-C-CAN4] |

|(internal): |Policy and Procedure for the Safe Management of Anticoagulant Therapy [RWF-OPPPCSS-C-CAN3] |

| |Venous Thromboembolism (VTE) in Pregnancy and Puerperium Guideline: prophylaxis, diagnosis and management |

| |[RWF-WC-OPG-MAT-CG57] |

| |Consent to Examination or Treatment, Policy and Procedure for [RWF-OPPPES-C-SM5] |

| |Guidelines for anticoagulation in adult patients with active malignancy [RWF-ONC-HAE-GUI-4] |

|Keywords: |Venous thromboembolism (VTE) |Deep vein thrombosis (DVT) |Pulmonary embolism (PE) |

| |Anticoagulation |Thrombolysis |D-dimer |

| |CTPA |Doppler ultrasound (US) |V/Q scan |

| |Warfarin |Dalteparin |Rivaroxaban |

| |Apixaban |Wells score |PESI score |

| |Ambulatory pathways |Doppler US | |

|Version control: |

|Issue: |Description of changes: |Date: |

|1.0 |First iteration of policy |October 2013 |

|1.1 |Amendment/deletion of text in 6.1.8 |April 2014 |

|2.0 |Revision of the policy and procedure – minor changes |June 2017 |

| |New appendices, revision of ambulatory pathways for DVT and PE, merge of AMU referral form, removal | |

| |of an appendix | |

Policy statement for:

Venous Thromboembolism (VTE), diagnosis and management in adults

Thromboembolism (VTE), diagnosis and management in adults, Procedure

1.0 Introduction and scope 6

2.0 Definitions / glossary 7

3.0 Duties 8

4.0 Training / competency requirements 8

5.0 Diagnosis 9

6.0 Treatment of proven VTE 11

7.0 Follow-up 16

APPENDIX 1 19

Process requirements 19

APPENDIX 2 20

CONSULTATION ON: Venous Thromboembolism (VTE), diagnosis and management in adults policy and procedure 20

APPENDIX 3 21

Equality impact assessment 21

FURTHER APPENDICES 22

1.0 Introduction and scope

For the purposes of this policy the term venous thromboembolism (VTE) refers to the most common location of thrombus, namely deep vein thrombosis (DVT) and pulmonary embolism (PE).

VTE is a common condition presenting to both primary and secondary care, either provoked or unprovoked. An estimated 25,000 people a year in the UK, and half a million a year in Europe, die from preventable in-hospital VTE and non-fatal VTE is responsible for considerable morbidity with conditions such as post-thrombotic syndrome (PTS) and chronic thromboembolic pulmonary hypertension (CTEPH). Although common, VTE can be complex to diagnose and treat due to the wide spectrum of clinical presentation and the side effects of potentially harmful treatment. Adherence to policy and processes developed from evidence based guidelines regarding investigation and treatment is therefore needed in order to minimise the risk of missing or under treating a potentially life threatening condition, and also to avoid the harms of over investigation.

This policy covers guidance on diagnosis, treatment and follow-up.

Diagnosis:

• Wells score for DVT and PE

• D-dimer measurement

• Imaging for DVT

• Imaging for PE

• Diagnostic pathways

Treatment:

• Type and duration of anticoagulation

• Thrombolysis

• Mechanical devices.

• VTE risk stratification

Follow up:

• Echocardiography

• Imaging for occult malignancy

• PTS prevention stockings

• Thrombophilia testing

See Appendix 13 for the ‘Summary guidelines for management of confirmed VTE’.

This policy applies to all healthcare professionals caring for adults presenting with confirmed or suspected VTE.

Prophylaxis against VTE is not addressed in this policy as there is a separate policy regarding this on Q-Pulse, Venous Thromboembolism Prevention Policy and Procedure [RWF-OPPPCSS-C-CAN4].

This policy does not cover VTE diagnosis and management in pregnancy. Please refer to the separate policy on Q-Pulse, Venous Thromboembolism (VTE) in Pregnancy and Puerperium Guideline: prophylaxis, diagnosis and management [RWF-WC-OPG-MAT-CG57]

2.0 Definitions / glossary

|AES |Anti-Embolism Stockings – stockings providing compression from the ankle upwards to increase venous blood flow and reduce |

| |stasis within the leg veins. A mechanical prophylactic device to reduce the risk of developing a DVT. |

|APTTR |Activated Partial Thromboplastin Time ratio – primary laboratory calculation used to monitor heparin therapy. |

|CTEPH |Chronic Thromboembolic Pulmonary Hypertension – increased pressure in the pulmonary arteries caused by pulmonary embolism |

| |resulting in respiratory symptoms. |

|CTPA |Computer Tomography Pulmonary Angiography – scan used to examine the lungs for PE. |

|DIC |Disseminated Intravascular Coagulation – pathological process characterized by the widespread activation of the clotting |

| |cascade that results in the formation of blood clots in the small blood vessels throughout the body. Bleeding can also |

| |occur. |

|Distal |Situated away from the centre of the body or point of attachment. |

|DOAC |Direct Oral Anticoagulants (rivaroxaban, apixaban, edoxaban and dabigatran) |

|Doppler |Ultrasound scan used to diagnose DVT – may be abbreviated to USS or Doppler. |

|DVT |Deep Vein Thrombosis – a thrombosis occurring in a deep vein, most commonly a deep vein of the leg or pelvis but can |

| |affect any deep vein. |

|EDN |Electronic Discharge Notification – summary of hospital admission and discharge medications. |

|eGFR |Estimated Glomerular Filtration Rate – a calculation providing an index on kidney function. |

|Factor Xa |Factor Xa – a protein in the activation process of the clotting cascade. |

|GCS |Graduated Compression Stockings – help promote circulation in the legs. Used more for patients with DVT or other clinical |

| |conditions as opposed to AES, which are used to prevent DVT. |

|IVC filters |Inferior vena caval filters – inserted to trap embolic thrombus from DVTs and prevent PE. |

|LMWH |Low molecular weight heparin (e.g. dalteparin) – subcutaneous anticoagulant. |

|(m)PESI |(modified) Pulmonary Embolism Severity Index |

|MTW |Maidstone and Tunbridge Wells NHS Trust |

|NICE |National Institute for Health and Care Excellence |

|PCC |Prothrombin Complex Concentrate |

|PE |Pulmonary Embolism – an embolism is created if a part or all of the thrombosis in the deep vein breaks off from the site |

| |where it is created and travels along the venous system, if the embolism reaches the lungs this is a pulmonary embolism. |

|Proximal |Situated nearer to the centre of the body or the point of attachment. |

|PTS |Post-Thrombotic Syndrome – long-term changes that can occur in the leg following a DVT that include pain, swelling, |

| |erythema and ulceration. |

|UFH |Unfractionated Heparin – subcutaneous or intravenous anticoagulant. |

|VKA |Vitamin K Antagonist (e.g. warfarin) – oral anticoagulant. |

|V/Q |Ventilation Perfusion – an alternative scan to CTPA to examine the lungs for PE. |

|VTE |Venous Thromboembolism – the collective term for DVT and PE. |

3.0 Duties

• Chief Executive has overall responsibility and accountability for the implementation of this policy.

• Medical Director has delegated responsibility for the implementation of this policy.

• Clinical Directors will be responsible for ensuring that the clinical staff within their area follow this policy. They will also review any audits undertaken to ensure highlighted actions are completed and implemented in a timely manner. Where indicated they will ensure directorate specific audits are completed.

• Lead for Thrombosis will be responsible for ensuring the Thrombosis Committee fulfil their responsibility in relation to this policy. The Lead for Thrombosis will also provide guidance and support as required.

• Thrombosis Committee will be responsible for ensuring audits are undertaken to monitor the effectiveness of the policy and ensure the policy is revised when necessary.

• VTE Lead Nurse will assist in the provision of education and training to implement this policy and undertake audits as necessary.

• Clinical staff -it is the registered professional’s responsibility to deliver care that is evidence based and in the best interests of the patient while taking into account the wishes of the patient or guardian.

4.0 Training / competency requirements

Registered medical staff have a professional responsibility to maintain their competence and read the updated policy, procedure and guidelines.

No specific training is required for the implementation or use of this policy; however, advice and guidance can be accessed from the on-call haematology Consultant or Specialist Trainee (Registrar).

5.0 Diagnosis

5.1 Risk factors

Major risk factors for VTE include a prior history of DVT and /or PE, age over 60 years, surgery, obesity, prolonged travel, acute medical illness, cancer, immobility, thrombophilia and pregnancy.

These risk factors are given a weighting according to the Wells score. In conjunction with clinical suspicion, a probability of VTE can be calculated from the patient’s symptoms and risk factors. This will then determine the need for further investigation, using either D-dimer or Doppler imaging.

5.2 Two level Wells score

A number of pre-test prediction scores for both DVT and PE, incorporating predisposing factors, symptoms and clinical signs have been developed. These involve using scoring systems to stratify patients into levels of risk of having DVT or PE.

NICE guidance (CCG 144 November 2015) has reviewed the Wells scores (original and revised), Geneva scores (original and revised) and Charlotte rule; it recommends use of the revised two level Wells score for both DVT and PE in conjunction with D-dimer testing in patients with clinically suspected VTE. (Appendix 4 – Two level Wells scores)

The Wells scores lack both sensitivity and specificity and should not be used in isolation; it therefore must be used in conjunction with D-dimer testing and/or imaging for the diagnosis of VTE, as detailed below. Wells score is only suitable for lower limb DVT.

5.3 D-dimer testing

The Trust uses HaemosIL D-dimer assay. This is a quantitative, highly sensitive assay that must be used in conjunction with the two level Wells score for the assessment of possible VTE.

As with all D-dimer assays the sensitivity is high at 100% but specificity poor at 54% with the manufacturer agreed cutoff of 243ng/ml. There is therefore a high rate of false positives. Clinical assessment and the Wells score must be used in interpreting values.

D-dimers are one of a group of fibrin degradation products that are formed when the coagulation cascade is activated. There are therefore many reasons for D-dimer formation. The most common clinical reasons for false positives include any inflammatory condition such as infection, rheumatoid arthritis, malignancy and ongoing bleeding. D-dimers are therefore unhelpful for patients already in hospital and should not be used; instead, Doppler imaging should be used in conjunction with the Wells score and clinical assessment.

False negatives most commonly occur if the test is delayed by several days and the patient has received anticoagulants.

The use of D-dimer measuring is restricted to the diagnosis of VTE and disseminated intravascular coagulation. In patients with suspected DVT, D-dimer should be requested if the Wells score makes DVT ‘unlikely’, or if the Wells score is ‘likely’ but Doppler imaging is negative or delayed.

In suspected PE, D-dimer should be requested if the Wells score is ‘unlikely’ and is therefore not indicated for ‘likely’ PEs. As with all investigations they should not be ordered unless the result would alter management.

Requests for D-dimer should be made on the electronic Order Communications system and will also require completion of the D-dimer request form (Appendix 5 – D-dimer mandatory request information), which should be sent with the sample to Haematology.

5.4 Doppler imaging for suspected lower limb DVT

Ultrasound imaging of the lower limbs for above calf DVT is approximately 90% sensitive and 94% specific. To rule out DVT a Doppler ultrasound scan (USS) should be used in conjunction with another test, namely D-dimer. The Trust has adopted the approach recommended by NICE CG144 guidance (November 2015). This involves Wells score assessment and D-dimer testing. MTW DVT diagnostic pathways mirror those advocated by NICE and are shown in Appendices 8 ‘Algorithm 1 Diagnosis of DVT ‘and 9 ‘DVT patient pathway’.

In summary, patients with a negative D-dimer and an ‘unlikely’ Wells score are deemed not to have a DVT and another cause of the patient’s symptoms should be sought. These may include: cellulitis, post-thrombotic syndrome, superficial thrombophlebitis, ruptured Baker’s cyst, haematoma in muscle, muscle tear or strain, dependent (stasis) oedema, lymphatic obstruction, arthritis, heart failure, cirrhosis or nephrotic syndrome, external compression of major veins e.g. by foetus or cancer, arteriovenous fistula.

Patients with an ‘unlikely’ Wells score and positive D-dimer should have a proximal leg Doppler USS. If negative they can be deemed as not having a DVT and another cause for the patient’s symptoms should be sought.

Patients who have a ‘likely’ Wells score should have proximal leg ultrasound and if negative should then be offered a D-dimer. If D-dimer is positive then they should be treated for a DVT and a repeat Doppler US scan performed 6 to 8 days later. If this is negative then they can be deemed as not having a DVT. Ongoing investigation should generally be done by the initial team or doctor.

5.5 Doppler imaging for suspected upper limb DVT

This is defined by thrombosis involving any of the axillary, subclavian, internal jugular or brachiocephalic veins. In cases of suspected upper limb DVT a Wells score is not appropriate. A Doppler US should be arranged of the affected upper limb. If the scan is positive then initiate anticoagulation as per proximal DVT. Anticoagulation duration should be for three months unless line related or associated with cancer. In these instances the duration should be 6 months and then review.

5.6 Imaging for suspected PE

Two main imaging modalities are used for diagnosis of PE. These are V/Q (Ventilation/Perfusion) and CTPA (Computer Tomography Pulmonary Angiography) scanning, both of which have limitations.

• V/Q scanning: There are two types of V/Q scanning, planar and SPECT. NICE CG144 reports that planar V/Q has a sensitivity of 40-100% and a specificity of 72-97% whilst 3D V/Q SPECT has a sensitivity of 100% and specificity of 87% respectively. It is noted that the SPECT figures are likely to be overestimated due to constraints of the studies. MTW offers V/Q SPECT rather than planar. Although V/Q scanning has shown comparable outcome data to CTPA, V/Q does not have the same ability to image other thoracic structures such as the right heart and major vessels.

• CTPA scanning: Evidence suggests that CTPA has a sensitivity of 80-100% and a specificity of 78-100%. Although approximately 15% of patients with suspected PE are likely to be unable to be able to have a CTPA, due to constraints such as renal failure, pregnancy or women of reproductive age, MTW has followed NICE guidance in suggesting that CTPA rather than V/Q should be the primary imaging modality. This is due to its ability to give faster results with less observer error and also due to concerns about the additional cost of offering both V/Q and CTPA to those patients with indeterminate V/Q results. The concerns about a higher radiation dose compared to V/Q are valid and in some cases V/Q should be considered, especially in the young or pregnant women who are unlikely to have other pathologies.

The MTW PE diagnostic pathway is shown in Appendix 6 ‘Algorithm 2 Diagnosis of PE‘. This has adopted the most cost effective strategy advocated by NICE CG144 which involves use of the Wells scores, either for DVT or PE, and D-dimer to decide on further imaging. This is enforced by the need for Wells scores to be made clear on the Trust’s electronic diagnostic Order Communications systems.

In summary if PE is clinically suspected and the two level Wells score is ‘likely’ then offer a CTPA, if PE is unlikely offer a D-dimer and a CTPA only if the D-dimer is positive. If a CTPA is not desired due to contraindications or concerns of radiation dose then consider bilateral above knee Doppler US followed by V/Q SPECT if negative. Patients with suspected PE and proven DVT do not need to go on to have further imaging as this will not change management.

6.0 Treatment of proven VTE

The mainstay of treatment for all forms of VTE is anticoagulation. Both thrombolysis and IVC filters do have a role but only in a minority of cases, which will be discussed below.

Anticoagulation prevents propagation of thrombus via inactivation of the clotting cascade. Thrombus resolution, or fibrinolysis, is achieved via intrinsic plasminogen activation thus thrombus may take a number of weeks to clear; this is clinically relevant if considering follow up imaging and when treating post-thrombotic complications.

6.1 Types of anticoagulation

6.1.1 Unfractionated Heparin (UFH) and Low Molecular Weight Heparin (LMWH)

In otherwise healthy individuals with VTE Low Molecular Weight Heparin should be offered whilst formal anticoagulation with an oral Vitamin K Antagonist (VKA) is achieved or patients may be started on rivaroxaban as detailed below.

The LMWH used at MTW for treatment of VTE is dalteparin, which is dosed according to weight and can be given in either a once daily or twice daily regime. The BD regime is recommended to those with a higher bleeding risk and in pregnancy.

UFH has been shown to be inferior to LMWH in both risk of recurrent VTE and major bleeding and it is therefore not recommended except in specific circumstances1. It must be noted that UFH requires close monitoring of APTTR and this is often poorly managed on general wards.

6.1.2 Renal impairment

In patients with an eGFR of 40mmHG for > 15 minutes without another cause.

Ideally a PE should be proven on imaging. In critically unstable patients a bedside echocardiogram can be helpful, and in those patients who have a high clinical suspicion of PE, thrombolysis should not be delayed while awaiting definitive investigation.

Systemic thrombolysis should not be considered in patients with PE and haemodynamic stability as there is as yet no proven benefit.

Please see Appendix 12 for the ‘Protocol for the management of massive PE with thrombolysis’ and Appendix 14 for a summary of ‘Use of in-hospital thrombolysis’).

6.4 Mechanical devices

There are two main mechanical therapies utilized in the treatment of VTE, inferior vena caval (IVC) filters and graduated compression hosiery.

6.4.1 Retrievable IVC filters

IVC filters are intended to trap embolic thrombus from DVTs and so prevent PE. They can either be temporary or permanent and are usually placed under radiological guidance. They are most commonly indicated in patients for whom anticoagulation is contraindicated or ineffective, or patients who require temporary interruption of anticoagulation, usually for surgery within 6 weeks of diagnosis of VTE. There is no consistent evidence that IVC filters are of benefit in patients with free floating thrombus.

Evidence suggests that IVC filters reduce the early rate of recurrent PE, though this benefit is lost within 2 years. There is no evidence of mortality benefit. Complications include a possible increased risk of DVT and direct filter related complications such as IVC perforation, filter migration and infection. If possible a removable filter should be used and removed as soon as possible. The decision to place a retrievable filter should be made by the team caring for the patient, in discussion with the radiologist placing the device. If the decision is made for a filter to be removed, then a date for the removal of the filter should be made by the intervening radiologist and communicated to the patient and responsible team.

Please refer to the appendix to Policy and Procedure for the Safe Management of Anticoagulant Therapy (Algorithm for retrievable vena caval filters in adults [RWF-ONC-HAE-GUI-2]).

6.4.2 Graduated compression stockings (GCS)

There are two main types of compression stockings, anti-embolic (AES) and graduated compression (GCS). They have different levels of compression and are not clinically interchangeable. AES are indicated for VTE prevention and GCS for venous ulcers, lymphoedema and prevention of post-thrombotic syndrome (PTS).

PTS can occur in up to a quarter of patients following DVT and carries significant morbidity. Previous evidence on the benefit of using GCS to reduce the risk of PTS development has now been questioned and the updated NICE guideline 144 has removed the recommendation to use GCS. However some patients with severe symptoms from their DVT (pain and / or swelling) may still benefit from the use of GCS. Peripheral vascular disease needs to be excluded prior to prescribing GCS.

GCS are usually issued by the patient’s GP and not during the hospital stay due to the required delay in fitting. Advice to wear stockings should be stated on the electronic discharge notification (EDN).

6.5 PE risk stratification and VTE outpatient treatment

There is now general acceptance that patients with low risk VTE can be treated successfully and safely as outpatients7, 8.

6.5.1 DVTs

A Cochrane review in 2007 showed lower rates of DVT recurrence and a trend towards decreased mortality with patients treated in an outpatient setting9. Probable confounding factors were the effect of LMWH versus UFH and the baseline characteristics of patients deemed suitable for outpatient care. This review shows that outpatient treatment of DVTs is at least as safe and effective as hospitalization.

The effect of ambulation on the risk of adverse outcomes has been assessed in a number of trials including a systematic review. The evidence is firmly in favour of early mobilisation of patients with DVTs11.

Indicators for adverse effects in DVT patients have been assessed via the RIETE registry10. This Spanish based prospective group found that indicators for adverse events were a body weight ................
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