Medicine: VTE Flashcards
1
Q
What’s proximal DVT?
A
DVT in popliteal vein or above
2
Q
What’s Virchow’s Triad?
A
Virchow’s triad → three broad categories of factors that are thought to contribute to thrombosis
3
Q
General risk factors associated with VTE
A
- increased risk with advancing age
- obesity
- family history of VTE
- pregnancy (especially puerperium)
- immobility
- hospitalisation
- anaesthesia
- central venous catheter: femoral >> subclavian
4
Q
Underlying conditions that may predispose to VTE
A
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
5
Q
Medications that may put a person at risk of developing VTE
A
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)
6
Q
Clinical presentation of DVT
A
- Pain
- Swelling
- Pitting oedema
- Tenderness
- Discolouration (redness)
- Heat
7
Q
Clinical presentation of PE
A
- Shortness of breath
- Cough
- Chest pain (pleuritic)
- Tachycardia
- Hypotension
- Low-grade fever
- Haemoptysis
8
Q
Complications of VTE
A
- 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
9
Q
How to reduce risk of VTE in in-patient patients?
A
- 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
10
Q
General risk factors of VTE for the patients admitted
A
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
11
Q
Risk factors of VTE specific for medical and surgical patients
A
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
12
Q
Patient-related risk factors for bleeding
A
13
Q
What causes of patient’s admission would increase their risk of bleeding?
A
- neurosurgery
- spinal surgery
- eye surgery
- LP/epidural/spinal anaesthesia within next 12 hours or previous 4 hours
- other procedures with high bleeding risks
14
Q
Types (2) of VTE prophylaxis
A
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
15
Q
What medical anti-thrombotic prophylaxis can be used in a patient with CKD?
A
Unfractionated heparin (UFH)
16
Q
How to reduce risk of VTE in hospital patient?
A
- 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
17
Q
Advice re COCP/HRT pre-surgery
A
Advise women to stop taking their combined oral contraceptive pill/hormone replacement therapy 4 weeks before surgery
18
Q
Examples of procedures where post- surgical prophylaxis is indicated
A
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
19
Q
Wells score components and results
A
Clinical probability simplified score
- DVT likely: 2 points or more
- DVT unlikely: 1 point or less
20
Q
What to do if:
- DVT is ‘likely’
A
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
21
Q
What to do if ‘DVT is unlikely’?
A
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)
22
Q
Management of DVT
A
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
23
Q
Further Ix in patients with ‘unprovoked’ DVT
A
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
24
Q
Do we offer a thrombophilia screen in patients with DVT?
A
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
25
Role of NOACs in DVT management
26
Which group of patients thrombolytic DVT therapy can be considered?
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.
27
Which patients are suitable for temporary IVC filter? (mechanical intervention for DVT)
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
28
Do we offer elastic stockings therapy for patients after proximal DVT?
* 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.
29
Risk factors for DVT in pregnancy
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.
30
Management of DVT in pregnancy
\*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
31
32
What Ix carry on first when PE is suspected?
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
33
Two-Level PE Wells Score
34
What to do if PE is 'likely'?
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
35
What to do if PE is 'unlikely'?
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
36
Contraindications to CTPA
* an allergy to contrast media
* renal impairment
* pregnancy
a V/Q scan should be used instead of a CTPA
37
When to diagnose PE and start treatment?
Diagnose PE and start treatment if positive CTPA or if PE identified with V/Q scan
38
Consider alternative diagnosis to PE in patients with...
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
39
Possible ECG findings in PE
* 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
40
CXR findings in PE
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
41
What's that?
42
43
Management of Pulmonary Embolism
**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')
44
When not to give LMWH in PE diagnosis?
* patients with a massive PE where thrombolysis is being considered
* unfractionated heparin should be used
45
In what circumstances do we consider extending use of warfarin and LMWH after PE diagnosis?
* extend warfarin beyond 3 months → for patients with *unprovoked* PE
* for patients with active cancer → LMWH for 6 months
46
When do we use thrombolytic therapy for PE?
When do we don't consider it?
* 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
47
In which group of patients do we use IVC as management of PE?
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
48
