Medicine: VTE

Question 1

What’s proximal DVT?

Answer 1

DVT in popliteal vein or above

Question 2

What’s Virchow’s Triad?

Answer 2

Virchow’s triad → three broad categories of factors that are thought to contribute to thrombosis

Question 3

General risk factors associated with VTE

Answer 3

• increased risk with advancing age
• obesity
• family history of VTE
• pregnancy (especially puerperium)
• immobility
• hospitalisation
• anaesthesia
• central venous catheter: femoral >> subclavian

Question 4

Underlying conditions that may predispose to VTE

Answer 4

Underlying conditions

• malignancy
• thrombophilia: e.g. Activated protein C resistance, protein C and S deficiency
• heart failure
• antiphospholipid syndrome
• Behcet’s
• polycythaemia
• nephrotic syndrome
• sickle cell disease
• paroxysmal nocturnal haemoglobinuria
• hyperviscosity syndrome
• homocystinuria

Question 5

Medications that may put a person at risk of developing VTE

Answer 5

Medication

• combined oral contraceptive pill: 3rd generation more than 2nd generation
• hormone replacement therapy: the risk of VTE is higher in women taking oestrogen + progestogen preparations compared to those taking oestrogen only preparations
• raloxifene and tamoxifen
• antipsychotics (especially olanzapine)

Question 6

Clinical presentation of DVT

Answer 6

• Pain
• Swelling
• Pitting oedema
• Tenderness
• Discolouration (redness)
• Heat

Question 7

Clinical presentation of PE

Answer 7

• Shortness of breath
• Cough
• Chest pain (pleuritic)
• Tachycardia
• Hypotension
• Low-grade fever
• Haemoptysis

Question 8

Complications of VTE

Answer 8

• Post-thrombotic syndrome (PTS) of the leg post DVT
• can occur within 1 - 2 years after DVT in 20% to 50% of all patients
• can lead to deep vein insufficiency and leg ulcers
• Death from PE
• Chronic thromboembolic pulmonary hypertension (CTPH)
• Secondary pulmonary hypertension can occur with right sided heart failure in the long-term post pulmonary emboli
• can occur after PE and is associated with

Question 9

How to reduce risk of VTE in in-patient patients?

Answer 9

• All patients admitted to hospital should be individually assessed to identify risk factors for VTE development and bleeding risk
• For medical and surgical patients the recommended risk proforma is the department of healths VTE risk assessment tool
• BALANCE risk of bleeding vs VTE

Question 10

General risk factors of VTE for the patients admitted

Answer 10

General risk factors:

• active cancer/chemotherapy
• aged over 60
• known blood clotting disorder (e.g. thrombophilia)
• BMI over 35
• dehydration
• one or more significant medical comorbidities (e.g. heart disease; metabolic/endocrine pathologies; respiratory disease; acute infectious disease and inflammatory conditions)
• critical care admission
• use of hormone replacement therapy (HRT)
• use of the combined oral contraceptive pill
• varicose veins
• pregnant or less than 6 weeks post-partum

Question 11

Risk factors of VTE specific for medical and surgical patients

Answer 11

Medical patients:

• significant reduction in mobility for 3 days or more (or anticipated to have significantly reduced mobility)

Surgical/trauma patients:

• hip/knee replacement
• hip fracture
• general anaesthetic and a surgical duration of over 90 minutes
• surgery of the pelvis or lower limb with a general anaesthetic and a surgical duration of over 60 minutes
• acute surgical admission with an inflammatory/intra-abdominal condition
• surgery with a significant reduction in mobility

Question 12

Patient-related risk factors for bleeding

Answer 12

Question 13

What causes of patient’s admission would increase their risk of bleeding?

Answer 13

• neurosurgery
• spinal surgery
• eye surgery
• LP/epidural/spinal anaesthesia within next 12 hours or previous 4 hours
• other procedures with high bleeding risks

Question 14

Types (2) of VTE prophylaxis

Answer 14

Types of VTE prophylaxis

Mechanical:

• Correctly fitted anti-embolism (aka compression) stockings (thigh or knee height)
• An Intermittent pneumatic compression device

Pharmacological:

• Fondaparinux sodium (SC injection)
• Low molecular weight heparin (LMWH) - e.g. enoxaparin (brand name = Clexane)
• Unfractionated heparin (UFH) - used in patients with chronic kidney disease

Question 15

What medical anti-thrombotic prophylaxis can be used in a patient with CKD?

Answer 15

Unfractionated heparin (UFH)

Question 16

How to reduce risk of VTE in hospital patient?

Answer 16

• Encourage patients to mobilise as soon as possible
• Do not allow patients to become dehydrated unless clinically indicated
• Consider VTE prophylaxis for people who are having antiplatelet agents for other conditions and whose risk of VTE outweighs their risk of bleeding
• Consider VTE prophylaxis for people at increased risk of VTE who are interrupting anticoagulant therapy

Question 17

Advice re COCP/HRT pre-surgery

Answer 17

Advise women to stop taking their combined oral contraceptive pill/hormone replacement therapy 4 weeks before surgery

Question 18

Examples of procedures where post- surgical prophylaxis is indicated

Answer 18

For certain surgical procedures (hip and knee replacements) pharmacological VTE prophylaxis is recommended for all patients to reduce the risk of a VTE developing post-surgery

Question 19

Wells score components and results

Answer 19

Clinical probability simplified score

• DVT likely: 2 points or more
• DVT unlikely: 1 point or less

Question 20

What to do if:

• DVT is ‘likely’

Answer 20

If a DVT is ‘likely’ (2 points or more)

• a proximal leg vein ultrasound scan should be carried out within 4 hours and, if the result is negative, a D-dimer test
• if a proximal leg vein ultrasound scan cannot be carried out within 4 hours a D-dimer test should be performed and low-molecular weight heparin administered whilst waiting for the proximal leg vein ultrasound scan (which should be performed within 24 hours)

*Repeat proximal leg vein ultrasound scan 6 - 8 days later for all patients with positive D-dimer test and negative proximal leg vein ultrasound scan

Question 21

What to do if ‘DVT is unlikely’?

Answer 21

If a DVT is ‘unlikely’ (1 point or less)

• perform a D-dimer test and if it is positive arrange:
• a proximal leg vein ultrasound scan within 4 hours
• if a proximal leg vein ultrasound scan cannot be carried out within 4 hours low-molecular weight heparin should be administered whilst waiting for the proximal leg vein ultrasound scan (which should be performed within 24 hours)

Question 22

Management of DVT

Answer 22

Low molecular weight heparin (LMWH) or fondaparinux should be given initially after a DVT is diagnosed.

• a vitamin K antagonist (i.e. warfarin) should be given within 24 hours of the diagnosis
• the LMWH or fondaparinux should be continued for at least 5 days or until the international normalised ratio (INR) is 2.0 or above for at least 24 hours, whichever is longer, i.e. LMWH or fondaparinux is given at the same time as warfarin until the INR is in the therapeutic range
• warfarin should be continued for at least 3 months. At 3 months, NICE advise that clinicians should ‘assess the risks and benefits of extending treatment’
• NICE add ‘consider extending warfarin beyond 3 months for patients with unprovoked proximal DVT if their risk of VTE recurrence is high and there is no additional risk of major bleeding’.

*In practice most clinicians give 6 months of warfarin for patients with an unprovoked DVT/PE

• for patients with active cancer NICE recommend using LMWH for 6 months

Question 23

Further Ix in patients with ‘unprovoked’ DVT

Answer 23

Offer all patients diagnosed with unprovoked DVT or PE who are not already known to have cancer the following investigations for cancer:

• a physical examination (guided by the patient’s full history) and
• a chest X-ray and
• blood tests (full blood count, serum calcium and liver function tests) and urinalysis.

Consider further investigations for cancer with an abdomino-pelvic CT scan (and a mammogram for women) in all patients aged over 40 years with a first unprovoked DVT or PE

Question 24

Do we offer a thrombophilia screen in patients with DVT?

Answer 24

Thrombophilia screening

• not offered if patients will be on lifelong warfarin (i.e. won’t alter management)
• consider testing for antiphospholipid antibodies if unprovoked DVT or PE
• consider testing for hereditary thrombophilia in patients who have had unprovoked DVT or PE and who have a first-degree relative who has had DVT or PE

Question 25

Role of NOACs in DVT management

Answer 25

Question 26

Which group of patients thrombolytic DVT therapy can be considered?

Answer 26

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.

Question 27

Which patients are suitable for temporary IVC filter? (mechanical intervention for DVT)

Answer 27

Temporary inferior vena caval filters * offer to patients with proximal DVT or PE who cannot have anticoagulation treatment * consider for patients with recurrent proximal DVT or PE despite adequate anticoagulation treatment (after considering alternatives) Ensure strategy for removing filter at earliest possible opportunity is planned and documented when filter is placed

Question 28

Do we offer elastic stockings therapy for patients after proximal DVT?

Answer 28

* Do not offer elastic graduated compression stockings to prevent post-thrombotic syndrome or VTE recurrence after a proximal DVT. * This recommendation does not cover the use of elastic stockings for the management of leg symptoms after DVT.

Question 29

Risk factors for DVT in pregnancy

Answer 29

High risk: previous VTE history → requires low molecular weight heparin throughout the antenatal period and also input from experts Intermediate risk of developing VTE due to hospitalisation, surgery, co-morbidities or thrombophilia → antenatal prophylactic low molecular weight heparin The assessment at booking should include risk factors that increase the womans likelihood of developing VTE. These risk factors include: * Age \> 35 * Body mass index \> 30 * Parity \> 3 * Smoker * Gross varicose veins * Current pre-eclampsia * Immobility * Family history of unprovoked VTE * Low risk thrombophilia * Multiple pregnancy * IVF pregnancy Four or more risk factors warrants immediate treatment with low molecular weight heparin continued until six weeks postnatal If a woman has three risk factors low molecular weight heparin should be initiated from 28 weeks and continued until six weeks postnatal.

Question 30

Management of DVT in pregnancy

Answer 30

\*If diagnosis of DVT is made shortly before delivery, continue anticoagulation treatment for at least 3 month, as in other patients with provoked DVTs. * **Therapeutic LMWH** is the anticoagulant of choice in pregnancy * **Systemic thrombolysis** should be administered for massive PE in pregnancy; however if bleeding risk is high (e.g. in the peripartum period) then surgical or mechanical methods are suggested, depending on local availability

Question 32

What Ix carry on first when PE is suspected?

Answer 32

Suspected PE → carry out the following to exclude other causes: 1. Medical history 2. Physical examination (chest, swollen leg) 3. chest X-ray •If PE suspected use the two-level PE Wells score

Question 33

Two-Level PE Wells Score

Answer 33

Question 34

What to do if PE is 'likely'?

Answer 34

If a PE is 'likely' (more than 4 points): * arrange an immediate computed tomography pulmonary angiogram (**CTPA**) * If there is a delay in getting the CTPA then give **low-molecular-weight heparin** until the scan is performed

Question 35

What to do if PE is 'unlikely'?

Answer 35

If a PE is 'unlikely' (4 points or less): * arrange a **D-dimer test** ​• If this is positive → an immediate computed tomography pulmonary angiogram (**CTPA**) • if there is a delay in getting the CTPA then give **low-molecular-weight heparin** until the scan is performed

Question 36

Contraindications to CTPA

Answer 36

* an allergy to contrast media * renal impairment * pregnancy a V/Q scan should be used instead of a CTPA

Question 37

When to diagnose PE and start treatment?

Answer 37

Diagnose PE and start treatment if positive CTPA or if PE identified with V/Q scan

Question 38

Consider alternative diagnosis to PE in patients with...

Answer 38

Consider alternative diagnoses in patient with: * unlikely two-level PE Wells score and: * negative D-dimer test or * positive D-dimer test and negative CTPA * likely two-level PE Wells score and: * negative CTPA and * no suspected DVT

Question 39

Possible ECG findings in PE

Answer 39

* large S wave in lead I, a large Q wave in lead III and an inverted T wave in lead III - 'S1Q3T3'(this change is seen in no more than 20% of patients * right bundle branch block and right axis deviation * sinus tachycardia

Question 40

CXR findings in PE

Answer 40

Chest x-ray * a chest x-ray is recommended for all patients to exclude other pathology * typically normal in PE * possible findings include a wedge-shaped opacification

Question 41

What's that?

Answer 41

Question 43

Management of Pulmonary Embolism

Answer 43

**Low molecular weight heparin** (LMWH) or **fondaparinux** → given initially after a PE is diagnosed * a v**itamin K antagonist (i.e. warfarin)** should be given within 24 hours of the diagnosis * the LMWH or fondaparinux should be continued for at least 5 days or until the international normalised ratio (INR) is 2.0 or above for at least 24 hours, whichever is longer, i.e. LMWH or fondaparinux is given at the same time as warfarin until the INR is in the therapeutic range * warfarin should be continued for at least 3 months (then 'assess the risks and benefits of extending treatment')

Question 44

When not to give LMWH in PE diagnosis?

Answer 44

* patients with a massive PE where thrombolysis is being considered * unfractionated heparin should be used

Question 45

In what circumstances do we consider extending use of warfarin and LMWH after PE diagnosis?

Answer 45

* extend warfarin beyond 3 months → for patients with *unprovoked* PE * for patients with active cancer → LMWH for 6 months

Question 46

When do we use thrombolytic therapy for PE? When do we don't consider it?

Answer 46

* For patients with PE and **haemodynamic instability** consider **thrombolytic therapy** (Massive PE = PE + Hypotension) * Do not offer to patients with PE and haemodynamic stability (PE + Normal BP, No RV dysfunction) * Submassive PE (PE + Normal BP but RV dysfunction) Not for thrombolysis

Question 47

In which group of patients do we use IVC as management of PE?

Answer 47

Patients who have **repeat pulmonary embolisms**, **despite adequate anticoagulation** →considered for inferior vena cava (IVC) filters These work by stopping clots formed in the deep veins of the leg from moving to the pulmonary arteries