Venous Thromboembolism DVT PE

Learning objectives

Learning
Understand
Integrate
Reflect

Introduction

Venous thromboembolism [VTE] is a common, potentially avoidable cause of morbidity and mortality in hospitalised patients
VTE is common in patients after stroke. Prevention and treatment are key
Most DVTs develop early, within the first week after the stroke.

KEY FACTS: Results of the CLOTS-1 and -2 studies showed that graduated compression stockings (either full-length or below-knee) are not effective in preventing VTE in stroke patients. Evidence from the CLOTS-3 study shows that intermittent pneumatic compression (IPC) not only reduces DVT, but also mortality.

Aetiology: Virchow's triad

Vessel problems: Stasis and compression of veins
Blood: Stroke, Infection, Inflammation may be a prothrombotic state
Flow: obstructed and loss of normal venous pump due to immobility due

Risks

Old age: risk x 4-6 over age of 70
Severity of paralysis
Previously documented DVT
Dehydration
Morbid obesity
Post-partum
Known thrombophilia
Malignancy
Recent Surgery

Epidemiology of Post stroke VTE

Asymptomatic DVT: up to 50%
Symptomatic DVT: 3%
Symptomatic PE: 1%

Clinical

Pain, swelling of leg may suggest a DVT
Chest pain and breathlessness, hypotension, cyanosis may suggest a PE
Stroke/Systemic embolism: Rare paradoxical embolus from VTE can cause stroke

Investigations

FBC, U&E, ESR, LFTs, CXR, Clotting profile.
ECG: Sinus tachycardia, RBBB, RAD, S1Q3T3
Troponin: Elevated Prognostic. Dimer: elevated but not needed if suspicion high
CT brain before any decision to anticoagulate if not already done
DVT requires a compression proximal leg vein ultrasound scan
PE requires a CTPA or a V/Q SPECT scan but if not available, a V/Q planar scan
If VTE suspected to be part of a malignancy process then CT Chest/abdomen/pelvis and Breast exam/mammogram should be considered

VTE Prevention

Anticoagulation:Prophylactic anticoagulation with unfractionated or low molecular weight heparin prevents DVTs but increases risk of intracranial and extracranial haemorrhage. The benefits are cancelled out. In fact the trials stated that prophylactic/low-dose heparin increased symptomatic ICH by more than they reduced symptomatic PE in patients with recent ischaemic stroke and cannot be recommended, but they may still be relevant in patients at very high risk of PE (e.g., morbid obesity, previous venous thromboembolism, and inherited thrombophilia) or if started later, although trials have not assessed these issues [1]. Prophylactic anticoagulation is not recommended for unselected stroke patients in the UK stroke guidelines [2].
Compression stockings:The CLOTS-1 and -2 studies [3] showed that graduated compression stockings (either full-length or below-knee) are not effective in preventing VTE in stroke patients.
Intermittent pneumatic compression: Evidence from the CLOTS-3 study [4] shows that intermittent pneumatic compression (IPC) reduces DVT and mortality. This should be started within three days of hospitalization and be provided continuously for 30 days, or until the patient is mobile or discharged

VTE Management

ABC If haemodynamic instability start IV fluids and ensure volume filled and give oxygen to support patient if SaO2 < 95%. In some cases patients with an Acute PE a patient my be pulseless and not breathing and may need resuscitation depending on resuscitation status. There are a variety of treatments but these are limited as they may have significant haemorrhagic risk. Occasionally one can only support with fluids, oxygen and after a few days patients may improve. Difficult cases likely to benefit from discussions with other experts and family.
Ischaemic stroke: If a PE or symptomatic proximal DVT is diagnosed or there is a high degree of certainty in patients with ischaemic stroke, full therapeutic anticoagulation is recommended. Warfarin or DOACs may be considered based on licensing and a balance of risks and benefits. They are continued for approximately 12 weeks depending on the ongoing risk profile and then a reassessment is made.
Haemorrhagic stroke: In those with an intracerebral haemorrhage, a vena cava filter might be an alternative, but this also requires anticoagulation in the longer term. IVC filters have an acceptable safety profile in stroke patients and appear to be effective in preventing life-threatening PE [5]. They do not treat the current PE which must be managed supportively. At a later stage anticoagulation may be started usually beyond 2 weeks but this must be based on an assessment of further VTE and ICH risk.
Catheter Thrombolysis to treat DVT Consider catheter-directed thrombolytic therapy for patients with symptomatic iliofemoral DVT who have symptoms of less than 14 days' duration and good functional status and a life expectancy of 1 year or more and a low risk of bleeding. This may be feasible in some patients with ischaemic stroke. Discuss with interventional radiology.
Systemic thrombolysis: Consider systemic thrombolytic therapy in patients with PE and haemodynamic instability but this must be on a case by case assessment as it may result in the real risk of haemorrhagic transformation for those with ischaemic stroke and would be contraindicated in haemorrhagic stroke.