IC4- VTE (DVT/ PE) Flashcards
What are the 3 factors under the Virchow’s Triad?
- Hypercoagulability
- Vascular Damage
- Circulatory stasis
What are some drugs that are risk factors for VTE?
Tamoxifen, raloxifene, ESAs and hormone Tx with estrogen (CoC, HRT)
What is the s/sx for DVT upon clinical presentation?
- Unilateral calf/ leg swelling (edema)
- Circumference of leg/ calf > 3cm difference than other leg/ calf
- Pain (hallmark)
- Warmth (hallmark)
- Tenderness at deep veins
- Colour changes in leg
What are the signs of DVT upon clinical presentation?
- Dilated superficial veins (“palpable cord”)
- Homan’s sign: pain in back of knee upon dorsiflexion of affected leg
What is the process of thromboembolism and how does PE occur?
Embolus above the knee is more likely to embolize → through right heart (inferior vena cava) → pulmonary arteriole system → pulmonary embolism → occlusion of blood flow (vascular supply) to lung → impaired gaseous exchange @ alveoli → necrosis → impaired O2 delivery to other organs → fatal circulatory collapse (if severe)
What are the s/sx for PE?
More respiratory symptoms:
- Cough
- Chest pain
- Chest tightness
- SOB
- Palpitation
- May cough/ spit out blood (hemoptysis)
- If massive: dizziness/ light-headedness
Serious:
Circulatory collapse + shock
What are the signs for PE?
- Tachypnoea
- Tachycardia
- Diaphoretic
- Neck veins may be distended
- Massive PE: cyanotic and hypotensive; Oximetry: hypoxic
(May go into cardinal shock and die within minutes)
What should we do after a DVT is suspected?
Complete the Well’s DVT score
What are the Well’s score factors and the scores for each? (8)
ALL 1 point each:
- Active cancer (treatment ongoing/ within previous 6 months/ palliative)
- Paralysis, paresis, recent plaster immobilization of lower extremeties
- Recently bedridden for ≥ 3d or major surgery within 4w
- Localized tenderness along distribution of deep venous system
- Entire leg swollen
- Calf swelling > 3cm when compared to asymptomatic leg (measured below tibial tuberosity)
- Pitting edema (greater in symptomatic leg)
- Collateral superficial veins (nonvaricose)
After the Well’s Score is done, if the patient has ≥ 3 points (DVT likely), what is the next step? Elaborate
Conduct Doppler ultrasound (complete duplex ultrasound).
- If proximal ultrasound negative → surveillance
- If distal DVT → anticoagulation or surveillance
- If proximal DVT → initiate anticoagulation
After the Well’s Score is done, if the patient has 0 points (DVT unlikely), or 1-2 points (moderate/ intermediate likelihood of DVT), then what is the next step? Elaborate
D-dimer test.
If D-dimer positive, proceed with Dopper Ultrasound imaging, next course of action depends on imaging results.
If D-dimer negative, then rule out DVT.
What are the factors of high-severity PE? (4)
- Haemodynamic instability
ONE of the following:
- Cardiac arrest
- Obstructive shock (SBP < 90 mmHg/ vasopressors required to achieve BP ≥ 90 mmHg despite adequate filling status in combination with end-organ dysfunction)
- Persistent hypotension (SBP < 90 mmHg or SBP drop ≥ 40 mmHg for > 15 min not caused by new-onset arrhythmia, hypovolemia or sepsis)
- PESI class III-V or sPESI ≥ 1
- RV dysfunction on TTE or CTPA
- Elevated cardiac troponin levels
What are the factors for intermediate-high severity PE? (3)
- PESI class III-V or sPESI ≥ 1
- RV dysfunction on TTE or CTPA
- Elevated cardiac troponin levels
When do we use thrombolytics?
ONLY use in very severe PE where patient is at high risk of death/ with haemolytic deterioration on anticoagulant Tx
What are the Well’s score factors for PE and the respective scores for each factor? (7)
- Clinical SSx of DVT (leg swelling, pain with palpitation) → 3 points
- Other diagnosis less likely than PE → 3 points
- HR > 100 → 1.5 points
- Immobilization (≥ 3 days) or surgery in previous 4w → 1.5 points
- DVT/ PE Hx → 1.5 points
- Hemoptysis → 1 point
- Malignancy → 1 point
What is the Well’s score for likely PE and unlikely PE?
> 4 points = PE likely
≤ 4 points = PE unlikely
If the Well’s score for PE is > 4 points (PE likely), what is the next step? Elaborate
Conduct imaging (CTPA preferred over V/Q unless pt has kidney impairment OR contrast media allergy).
If positive, then initiate anticoagulation.
If the Well’s score for PE is ≤ 4 points (PE unlikely), what is the next step? Elaborate
Conduct D-dimer test.
If negative → rule out PE
If positive → conduct imaging (CTPA preferred over V/Q unless pt has kidney impairment OR contrast media allergy)
What is the most commonly used oral anticoagulant used for VTE? Why?
Apixaban. Used more commonly than Rivaroxaban in local practice as it is subsidised.
For Tx of VTE, what is the dosing schedule for Apixaban?
What about for renal impairment?
Apixaban:
10mg BD x 7d, followed by 5mg BD up to 6m then 2.5mg BD for VTEp extended Tx
Renal impairment: use with caution if CrCl 15-29 mL/min, AVOID in HD pts
For Tx of VTE, what is the dosing schedule for Rivaroxaban?
What about for renal impairment?
Rivaroxaban:
15mg BD x 3w, followed by 20mg/d for up to 6m then 10mg OM
Renal impairment: AVOID if CrCl < 30mL/min
For Tx of VTE, what is the dosing schedule for Warfarin?
What about for renal impairment?
Individualised dosing PO daily, overlap with parenteral (SC) anticoagulant (UFH/ LMWH/ fondaparinux) for ≥ 5 days.
*Enoxaparin (LMWH)
- (SC) 1mg/kg Q12H (preferred) or 1.5mg/kg OD
- Severe renal impairment (CrCl < 30mL/min): 1mg/kg OD (BD → OD)
UFH:
(IV) 80 units/kg body weight bolus, followed by 18 units/kg/h infusion
For Tx of VTE, what is the dosing schedule for Dabigatran/ Edoxaban?
What about for renal impairment?
Parenteral anticoagulant for ≥ 5d followed by:
(1) Dabigatran 150mg PO BD; or
(2) Edoxaban 60mg PO OD
Renal impairment:
- Dabigatran: avoid if CrCl < 50mL/min + avoid concomitant PgP inhibitors
- Edoxaban: CrCl 30-50mL/min or BW ≤ 60kg → 30mg PO OD. C/I if CrCl > 95 ml/min
For DVT Tx in general, when do we do:
- Survelliance
- 3 months Tx duration
- 6 months Tx duration
- Survelliance
- Isolated distal DVT with low risk recurrence (OR can do 4-6w AC Tx) - 3 months Tx duration
- Provoked DVT/ PE, transient (and reversible) risk factors
- Isolated distal DVT with high risk recurrence - 6 months Tx duration
- Unprovoked VTE (ie cannot attribute a cause for pt’s DVT)
- First unprovoked proximal DVT/ PE
What should we give for active cancer pts with VTE?
- Consider LMWH monotherapy
- Tx for at least 6 months total
- After 6 months, assess and continue beyond 6 months if
ongoing active cancer, acceptable bleeding risk
What are some important criterias for use of thrombolytics?
- Tx must be within 4.5h of onset (if between 3 - 4.5h after stroke, additional exclusion criteria)
Additional exclusion criteria (roughly know, can just read):
1. Age > 80y
2. Hx of prior stroke AND DM
3. Anticoagulant use prior to admission
4. NIHSS > 25
5. CT findings involving more than 1/3 of MCA territory (as evidenced by hypodensity, sulcal effacement or mass effect)
What are the 2 types of thrombolytics? What are their routes of administration?
Tenecteplase and alteplase.
Infusion.
What is tenecteplase generally used for?
Is it still commonly used in clinical practice today?
Better than alteplase in thrombolysis for acute myocardial infarction (AMI) due to ease of dosing and administration
Hardly used locally → acute centres have primary PCI services for AMI
Elaborate on the use of alteplase as a thrombolytic for PE.
Name some inclusion and exclusion criterias (the more impt ones)
- BP control critical to avoid intracranial haemorrhage (ICH)
Thrombolysis checklist:
Inclusion criteria
- Clinical diagnosis of AIS
- Able to start Tx within 4.5h of onset (if between 3 - 4.5h after stroke, additional exclusion criteria)
Exclusion criteria
- Onset > 4.5h ago
- Risk factors for bleeding (eg stroke/ serious head trauma within past 3 months, GI bleeding, high BP)
- Use of concomitant anticoagulants
- Pregnancy
How often should we follow up with pts on extended Tx?
At least once a year
For pts with first unprovoked proximal DVT or PE wishing to stop anticoagulation after 3m, what else can we give?
Low-dose aspirin if not contraindicated (less effective than anticoagulants, but more effective than no Tx in preventing VTE recurrence)
When will you consider giving the pt lifelong Tx for VTE?
Consider lifelong medication Tx (prophylactic DVT Tx) if you think the pt will always have the irreversible risk factor there (eg morbid obesity, APS, very frail and elderly pt which cannot ambulate much)
Note: Prolonging anticoagulation protects from recurrence (70-90%) BUT exposes to risk of unpredictable bleeding complications
Are the Tx duration guidelines for PE the same as DVT?
What are some other factors to consider regarding APS pts and what must we monitor regularly for pts receiving extended Tx? (6m)
Yes
- PO anticoagulant Tx with VKA for indefinite period for pts with APS
- In pts who receive extended anticoagulation, it is recommended that drug tolerance and adherence, hepatic, renal function, and bleeding risk be reassessed at regular intervals
What is the Tx for high risk PE?
- UFH (weight-adjusted bolus injection) PLUS
- Systemic thrombolytic Tx PLUS
- Supportive management (eg inotropes, fluid replacement etc)
Why is UFH used over LMWH for Tx of high risk PE?
Easily reversible, impt if pt is hemodynamically unstable
What is the Tx for intermediate-low risk PE?
- May initiate parenteral anticoagulation → LMWH recommended over UFH (if you feel that the situation is serious)
OR
- If PO anticoagulation is to be started, DOAC (apixaban, rivaroxaban, dabigatran, edoxaban) is preferred to VKA (warfarin)
- If VKA started, overlap with parental anticoagulant like LMWH until INR 2.5 is reached (as warfarin takes time to exert effects)
What type of patients would you NOT use DOACs for intermediate-low risk of PE?
- NOACs NOT recommended for severe renal impairment (use LMWH), during pregnancy and lactation (use LMWH), and pts with APS
Are pts with first symptomatic unprovoked DVT at higher risk of recurrence or those with first unprovoked PE?
Pts with first symptomatic unprovoked DVT are at higher risk of recurrence
Which anticoagulant do we use for pregnancy? What is the dosing?
How about the other anticoagulants?
Drug of choice is LMWH, (SC) 1mg/kg Q12H
Insufficient evidence for DOACs, VKAs are teratogenic in 1st trimester- maybe ok to use in 2nd and 3rd but better not take the risk
If a patient has multiple, recurrent miscarriages/ recurrent VTE, what can you suspect?
Anti-phospholipid syndrome
What is the dosing for LMWH (enoxaparin) for VTEp for
1) Medically ill + most surgeries
2) Total hip replacement/ hip fracture surgery?
What is the duration?
What is the renal dose adjustment for CrCl 30-50ml/min and CrCl < 30ml/min?
Duration: 10-14d, up to 35d
- Medically ill + most surgeries
40mg OD until ambulatory - Total hip replacement/ hip fracture surgery
40mg OD or 30mg BD
⚠️Renal impairment: (moderate) CrCl 30-50ml/min; for trauma pts 30mg BD consider anti-factor Xa levels
(severe) CrCl < 30ml/min; 20mg or 30mg OD
