Please note: this guideline has exceeded its review date and is currently under review by specialists. Exercise caution in the use of the clinical guideline.
For suspected venous thromboembolism (VTE) in pregnant patients, refer to separate guideline here
Fifty percent of Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE) arise spontaneously, without any obvious triggering event; there are many risk factors which are particularly common in hospitalised patients.
Early recognition and treatment of an acute venous thromboembolism (VTE) is essential to reduce the risk of early fatal PE. It is estimated that deaths from healthcare associated PE far exceed those from healthcare associated infection.
Signs and symptoms which may accompany an acute DVT or PE include:
In almost all suspected cases positive radiological confirmation will be required. However, for those presenting from the community it may be possible to rule out such a diagnosis by use of pre-test clinical probability scoring schemes in conjunction with measurement of fibrin D-dimer levels, which are almost invariably increased in cases of acute VTE (see decision algorithms for suspected DVT and PE below). D-Dimer measurement is not useful in the diagnosis of VTE in pregnant women or already hospitalised patients and should not be measured in these patient groups.
If DVT or PE is not excluded by the above, or the patient is already hospitalised then:
Brief guidance is given below. Full guidance on the diagnosis and early management of a suspected massive PE can be found on NHSGGC StaffNet / Clinical Info / Clinical Guidelines Directory and search for 'Suspected Massive PE' guideline.
PE associated with a systolic blood pressure <90mmHg or a drop in systolic blood pressure of >40mmHg from baseline for a period >15 minutes (not otherwise explained by hypovolaemia, sepsis or new arrhythmia)
If thrombolysis contraindicated, consider percutaneous catheter fragmentation or surgical embolectomy. Be aware that when considering thrombolysis the risk of major haemorrhage is significantly increased in the older patient.
Patients with chronic heart failure or suspected bilateral DVT and patients at extremes of weight or with renal impairment (i.e. CrCl <30ml/minute) preventing the safe use of LMWH, may not be suitable for out-patient investigation and management of suspected VTE.
|Active cancer (treatment ongoing, within previous 6 months or palliative)||1|
|Paralysis, paresis or recent plaster immobilisation of lower extremities||1|
|Recently bedridden for ≥3 days or major surgery within 12 weeks||1|
|Localised tenderness along distribution of deep venous system||1|
|Entire leg swollen||1|
|Calf swollen by ≥3cm compared to asymptomatic leg (10cm below tibial tuberosity)||1|
|Pitting oedema (greater in symptomatic leg)||1|
|Collateral superficial veins (non-varicose)||1|
|Previously documented DVT||1|
|Alternative diagnosis as likely or greater than that of DVT||-2|
|From The New England Journal of Medicine, Philip S. Wells, David R. Anderson, Marc Rodger, et al., Evaluation of D-Dimer in the Diagnosis of Suspected Deep-Vein Thrombosis, 349(13), 1227-35. Copyright © (2013) Massachusetts Medical Society. Adapted with permission from Massachusetts Medical Society.|
Score < 2: DVT unlikely
Score ≥2: DVT possible
Wells Clinical score should be utilised in all NHSGGC hospitals when DVT is suspected in out-patients
(use Wells clinical score, table 1 above)
Wells clinical score <2 and D-dimer negative – DVT unlikely. Consider other diagnosis before discharge and issue patient information sheet.
Wells clinical score <2 and D-dimer positive – continue below
Wells clinical score ≥2 (irrespective of D-dimer) – continue below
Treat as DVT until ultrasound result available.
Is patient suitable for out-patient management? If IV drug misuser, follow specific guidance on NHSGGC StaffNet.
Out-patients who have a negative ultrasound should discontinue anticoagulation and be considered for a repeat scan at 5–7 days if there is no likely alternative diagnosis for their leg symptoms.
|Age >65 years||1|
|Previous DVT / PE||3|
|Recent surgery or recent lower limb fracture (≤1 month)||2|
|Malignant disease (active or cured ≤1 year)||2|
|Unilateral lower limb pain||3|
|Heart rate 74–94bpm||3|
|Heart rate ≥95bpm||5|
|Pain on deep venous palpitation of leg and unilateral oedema||4|
|Le Gal G, Righini M, Roy PM, et al. (February 2006). Prediction of pulmonary embolism in the emergency department: the revised Geneva score. Annals of Internal Medicine 144(3); 165-171. Copyright © 2013 The American College of Physicians. All Rights Reserved. Adapted with permission from The American College of Physicians.|
Full guidance is available on StaffNet in the Clinical Guideline Electronic Resource Directory in the Haematology section under 'Suspected PE non massive'.
|Perform D-dimer and troponin|
Revised Geneva predictive risk score (table 2):
Low risk (score 0–3) – continue below.
Intermediate risk (score 4–10) – continue below.
High risk (score ≥11) – see here.
D-dimer negative – PE not likely, consider other diagnosis.
D-dimer positive – administer LMWH treatment dose and continue below.
If this is not readily available and patient is clinically stable with normal CXR and no underlying lung disease, then V/Q scan may be an alternative diagnostic option.
No PE – consider other diagnosis.
PE present – commence apixaban or warfarin and continue below.
|Risk stratify according to troponin and RV size (from CTPA or by echo)|
RV normal, troponin normal – low 30-day mortality. Consider early discharge and OP management.
RV dilated, troponin normal – intermediate 30-day mortality.
RV dilated or RV thrombus and troponin elevated – high 30-day mortality.
A duration of 3 months of therapeutic anticoagulation should be sufficient for most patients (longer term anticoagulation should be considered for those who have had recurrent thrombosis or are considered at high risk of a recurrent event), normally using either oral apixaban or LMWH initially followed by oral warfarin (with an overlap of at least 5 days) for 3 months. For details on the use of apixaban in acute DVT or PE, see Drug therapy / treatment options section below.
Patients with active cancer
Patients with superficial thrombophlebitis
Some patients with extensive superficial thrombophlebitis proximal to the knee can be considered for 6 weeks of anticoagulation with prophylactic dose LMWH (i.e. enoxaparin 40mg once daily). A full guideline pertaining to this management is available on NHSGGC StaffNet / Clinical Info / Clinical Guidelines Directory and search for 'superficial thrombophlebitis' guideline.
IV Drug Misusers
An algorithm to inform the decision as to which treatment option is the most suitable and with details of treatment for related conditions (e.g. cellulitis) is available on NHSGGC StaffNet / Clinical Info / Clinical Guidelines Directory and search for 'IVDU'. If it is perceived that the patient will be more compliant with once-daily dosing then rivaroxaban should be considered in place of apixaban.
Screening for cancer in patients with unprovoked venous thrombosis
Investigation for occult malignancy in unprovoked VTE, in patients over 40 years old, should involve full clinical history and examination, basic laboratory testing, chest x-ray, urinalysis and any age-appropriate cancer screening if not already performed. Routine extensive screening is not recommended. Rather, investigation for occult malignancy in VTE should be directed by, and be appropriate to, clinical signs and symptoms presented at diagnosis.
Thrombophilia testing is warranted in some patients who experience a VTE but should not be performed at the time of the acute event or during anticoagulation therapy.
Subcutaneous LMWH (see separate guideline here for dosing in pregnant patients).
Dalteparin is the LMWH of choice across NHSGGC for the initial treatment of VTE unless the patient is pregnant, has specific contraindications to dalteparin, or is to be treated with apixaban. Most patients with cancer should continue treatment with LMWH for the duration that anticoagulation is required.
Continue with dalteparin until:
Dose is 200units/kg subcutaneously once daily. 18,000units is the maximum recommended daily dose.
|Actual weight (kg)||Dalteparin daily dose (units) using pre-filled syringes||Dalteparin Syringe Colour|
|APTT ratio||Sodium Heparin Infusion Rate Change|
|>4||Stop for 60 minutes and recheck APTT ratio, before recommencing at a rate reduced by 300–500units/hour|
|3.5–4||Stop for 60 minutes and reduce heparin by 200units/hour|
|2.9–3.4||Stop for 30 minutes and reduce heparin by 100units/hour|
|1.2–1.7||Increase heparin by 200units/hour|
|<1.2||Increase heparin by 400units/hour and consider further bolus of 5,000units heparin|
Apixaban is curently the NHSGGC preferred DOAC for acute treatment and long-term secondary prevention of DVT and/or PE. Rivaroxaban and dabigatran remain on formulary as an option for acute treatment of DVT and/or PE in patients where these drugs are thought to be preferable (see separate guidance see NHSGGC StaffNet / Clinical Info / Clinical Guidelines Directory and search for 'rivaroxaban for the treatment of acute DVT or PE' guideline).
Apixaban and rivaroxaban are oral direct factor Xa inhibitors and dabigatran is an oral direct factor IIa inhibitor. All three have shown to be as effective as LMWH followed by warfarin in the treatment of acute PE and/or DVT. No monitoring of the anticoagulant effect of any of these medications is required, and although all have a short half-life, only dabigatran has a reversing agent, idarucizumab (Praxbind®).
The warfarin flexible induction (Age-adjusted Fennerty) regimen (see NHSGGC StaffNet / Clinical Info / Clinical Guideline Directory and search for 'warfarin induction protocols') gives dosing advice for the first 4 days of warfarin initiation only. It is not appropriate for dosing from day 5 onwards which should be undertaken manually using clinical judgement.