Recommendation grades (A-C) and levels of evidence (Ia-IV) are defined at the end of the "Major Recommendations" field.
Criteria for Outpatient Therapy
Where local arrangements exist, in uncomplicated deep venous thrombosis (DVT), low molecular weight heparin (LMWH) is safe to administer on an outpatient basis. The following are unlikely to be suitable for outpatient treatment.
- Patients with co-existent serious medical pathology.
- Severe acute venous obstruction (phlegmasia cerulea dolens).
- Patients in significant pain.
- Significant renal impairment (creatinine in excess of 200 micromoles per liter).
- Known heparin allergy or heparin-associated thrombocytopenia.
- Suspected problems with adherence to treatment.
- Communication problems (deafness, language difficulties, lack of home telephone).
- Poor social circumstances.
- Patients with limited mobility.
- Patients with active bleeding.
- Patients at significant risk of bleeding.
- Active peptic ulceration
- Liver disease (prothrombin time [PT] >2 seconds beyond normal range)
- Uncontrolled hypertension (diastolic blood pressure >110 millimeters mercury [mmHg], systolic blood pressure >200 mmHg)
- Angiodysplasia
- Recent eye or CNS surgery (within 1 month)
- Recent haemorrhagic stroke (within 1 month)
- Thrombocytopenia (platelet count below 100 × 109 cells per liter)
Pregnancy
It should be noted that pregnant women were excluded from the published trials demonstrating the efficacy of ambulatory care. Furthermore, appropriate LMWH dosing schedules have not been definitively established in pregnancy and there is also continuing debate about the need for monitoring of LMWH by an anti-Xa assay during pregnancy.
Nevertheless, despite the lack of published evidence, it is reasonable to treat pregnant patients with DVT with LMWH on an outpatient basis.
Integrated Care Pathway
There must be an integrated care pathway, with clearly defined lines of responsibility, for the management of such patients (Appendices 2 and 3 of the original guideline document). This will usually involve two separate processes.
Diagnosis
Whilst this traditionally falls under the responsibility of accident/emergency (A/E) departments or medical assessment units (MAU) an as yet relatively small number of Haematology departments have taken on this function. Where this latter situation applies, this must be clearly articulated in local clinical care pathways and must be accompanied by appropriate staffing and financial resource.
Treatment
This will usually fall under the auspices of the Haematology department.
Whatever the local arrangements, the patient must at all times know who to contact in the event of problems arising.
The care pathway should be approved by all relevant stakeholders and the local clinical policy board.
The Diagnostic Process
Updated guidelines on the diagnosis of venous thrombosis have recently been produced by the British Committee on Standards for Haematology (BCSH). The diagnosis of venous thromboembolism has lately been facilitated by the advent of validated clinical probability scores and second generation d-dimer assays. This may allow the discharge of a subgroup of patients without further radiological investigation.
For an outpatient therapy programme to be effective it is important that there should be no undue delay (which might therefore necessitate admission) in the diagnosis of the patient. It is therefore essential that a number of dedicated diagnostic imaging slots should be reserved each day for the diagnosis of patients with DVT who might then be suitable for outpatient care. This will need to be discussed and agreed with local radiologists and appropriately resourced by local management.
Those patients who are considered on clinical grounds as being at high risk of DVT should be treated with therapeutic doses of LMWH pending confirmation of the diagnosis. Appropriate local arrangements will need to be established for out of hours care.
It is not considered good medical practice for the patient to be treated on this presumptive basis for more than 24 hours, as for many patients this would involve unnecessary treatment and an unacceptable degree of risk.
The diagnosis of DVT, and possible suitability for outpatient care, is usually the responsibility of the on-call medical team/A/E, depending on local arrangements. Where by local agreement the haematology department does take responsibility for diagnosis this must be clearly articulated in local clinical care pathways and resourced appropriately.
The role of the haematology department in the management of these patients usually begins when a patient with objectively confirmed DVT is in the opinion of the assessing doctor suitable for outpatient care.
These critical lines of responsibility must be clearly articulated in local clinical care pathways.
Medical Assessment
Local arrangements need to ensure that appropriate arrangements are in place for the patient to receive a comprehensive medical review at diagnosis, particularly in regard to the following:
- Would the patient be suitable for outpatient therapy?
- Is there any evidence of limb ischaemia?
- Are there any associated pathologies – cancer, polycythaemia, etc.?
- Will medical follow-up as an outpatient be required?
Analgesia
The attending medical team should issue the patient with appropriate analgesia. Non–steroidal anti-inflammatory agents and aspirin-containing medications should be avoided.
Support Stockings
Arrangements should be made for the patient to receive appropriately fitting grade II compression stockings which significantly reduce the incidence of the post-thrombotic syndrome (grade A recommendation, level 1B [Brandjes et al., 1997]). This may best be carried out a few days after the thrombotic event, once the swelling in the affected leg has begun to reduce.
The patient should then be educated in the importance of wearing the stockings for at least 2 years and given advice about appropriate exercise and limb elevation.
Possible Models of Ambulant Care
In practice, there are several potential models of care for the patient with DVT receiving outpatient treatment.
- Daily attendance at Haematology department/MAU/A/E.
- Domiciliary care, administered by outreach haemostasis nurses.
- Domiciliary care, administered by district nurses and general practitioners.
- Domiciliary care, with injection of LMWH by patient or relative.
Each of these systems has been shown to be a practical way of delivering effective care. Appropriate training programmes and competency assessments must be established for patients administering their own treatment.
The Role of the Haemostasis Nurse Specialist
Outpatient management care programmes for DVT are greatly facilitated by the appointment of a haemostasis nurse specialist who will act as a critical coordinator, liaising with the various departments involved in the care of the patient and carrying out the following functions:
- Administration of outpatient care programme
- Commencement and control of anticoagulant therapy
- Monitoring for signs of thrombus extension or pulmonary embolism (PE)
- Liaison with community agencies and general practitioners
- Patient information and education
Starting Anticoagulant Treatment
Anticoagulation is the standard treatment for venous thromboembolism. Subcutaneous daily LMWH should be used for DVT. At this time it is agreed that no significant differences in clinical effectiveness have been established between the different preparations of LMWH. Whatever LMWH is chosen for local use it must carry a full product licence. Monitoring the activated partial thromboplastin time (APTT) is unnecessary. Baseline bloods for platelet count, PT, APTT, renal and liver function should be taken.
Warfarin is started as soon as the diagnosis is made and should be given after the first injection of LMWH. Patients with previous allergy or resistance to warfarin should be treated with acenocoumarol or phenindione. Warfarin is teratogenic and must be avoided during the first trimester of pregnancy. There may be rare occasions where a pregnant patient may require warfarin during the second trimester but this should only be given in close collaboration with a consultant haematologist.
LMWH should be administered for at least 5 days or until the international normalised ratio (INR) has been in the therapeutic range for two successive days, whichever is the longer (grade C recommendation, level IV). This is because the INR is raised as a result of low levels of factor VII in the early stages of warfarinization, but full anticoagulation is not achieved until the other vitamin K dependent clotting factors (II, IX and X) become depressed. This usually takes 3–5 days. A full blood count should be arranged after 5 days on LMWH – and throughout the period of LMWH treatment – to exclude the possibility of heparin-related thrombocytopenia. Patients with previous exposure to heparin within the past 100 days should also have a platelet count performed before the second dose of heparin.
Oral anticoagulant treatment should be given according to thrombosis task force guidelines (BCSH Haemostasis and Thrombosis Task Force, 1998). A baseline INR should be carried out. The initiation of oral anticoagulant treatment may be carried out according to a nomogram (grade B recommendation, level IIB), an example of which is given as Appendix 4 of the original guideline document. In most circumstances, the INR will need to be checked daily until the therapeutic range (usually 2–3) is achieved. Beware of potential interactions (particularly amiodarone, tamoxifen, macrolide antibiotics and NSAID). A lower initial dose will usually be required in the following circumstances:
- Elderly (over 70)
- Liver disease
- Alcohol abuse
- Body weight <50 kg
- Congestive heart failure
Duration and Intensity of Anticoagulant Therapy
The duration and intensity of oral anticoagulant treatment are determined by the clinical aspects of the individual case. General principles are set out in the relevant Haemostasis and Thrombosis Task Force guidelines.
- Guidelines on anticoagulant treatment (1998).
- Guidelines on investigation and management of heritable thrombophilia (2001).
- Guidelines for the investigation and management of the antiphospholipid syndrome (2000).
Outpatient Therapy of Pulmonary Embolism
PE carries a higher mortality than DVT. Whilst many patients will require hospital admission there is a subgroup of patients who present with peripheral PE (pleuritic chest pain and/or haemoptysis) who can safely be treated on an outpatient basis.
Patient Education
The patient and family should be fully informed and educated prior to being discharged on an ambulatory care progamme; verbal information should be supplemented by appropriate patient leaflets.
Lines of Responsibility
Diagnostic Team
- Investigation of possible venous thromboembolism
- Provision of appropriate analgesia
- Assessment of patients with confirmed DVT for outpatient care
- Assessment of requirement for medical outpatient follow-up
- Investigation of possible DVT recurrence
- Formal medical assessment for associated pathology
- Liaison with general practitioners
Treatment Team
- Administration of outpatient care programme
- Liaison with community agencies and general practitioners
- Provision of appropriate support stockings
- Patient information and education
- Thrombophilia testing where appropriate
- Commencement and control of anticoagulant therapy
- Daily assessment for signs of thrombus extension or PE
Definitions:
Levels of Evidence
Ia Meta analysis of randomized controlled trials
Ib At least one randomized controlled trial
IIa At least one well-designed study without randomization
IIb At least one well-designed quasi-experimental study
III Well-designed non-experimental descriptive studies
IV Expert committee reports or opinions and/or clinical experience of respected authorities
Grades of Recommendation
Grade A (evidence levels Ia, Ib) Requires at least one randomized controlled trial as part of the body of literature of overall good quality and consistency addressing the specific recommendation
Grade B (evidence levels IIa, IIb, III) Requires availability of well conducted clinical studies but no randomized controlled trials on the topic of recommendation
Grade C (evidence level IV) Requires evidence from expert committee reports or opinions and/or clinical experience of respected authorities; indicates absence of directly applicable studies of good quality
