Venous Thromboembolism Flashcards
what are the most common presentations of venous thrombosis
- deep venous thrombosis
- pulmonary embolism
venous thromboembolism pathogenesis: Virchow’s triad
- stasis: alterations in blood flow
- vessel wall injury
- hypercoagulability
what are some acquired risk factors (chronic conditions) for VTE
- malignancy
- antiphospholipid antibody syndrome
- myeloproliferative disorders
what is a major risk for VTE
previous thrombotic event
what are some acquired risk factors (transient states) for VTE
- surgery
- trauma
- immobilization
what are some acquired risk factors (female specific) for VTE
- pregnancy
- hormonal contraceptives
what are the most common inherited risk factors for VTE
- Factor V Leiden mutation
- Prothrombin gene mutation
What is the pretest probablity scoring system for VTE
Wells criteria
clinical presentation of DVT
- can be asymptomatic
- affected area may have
- swelling
- pain
- warmth
- redness or discoloration
- palpable cord (thrombosed vein)
homan’s sign
- positive sign: pain in the calf on forceful and abrupt dorsiflexion of the patient’s foot at the ankle when the knee is extended
- **test has fallen out of favor
Name some important criteria in wells scoring
- paralysis, orthopeding casting (1 point)
- bedridden, major surgery (1 point)
- tenderness (1 point)
- swelling of entire leg (1 point)
- calf swelling (1 point)
- pitting edema (1 point)
- cancer (1 point)
- alternative diagnosis more likely than DVT (-2 points)
wells scoring (numbers showing probability)
- 3-8 points = high probability
- 1-2 points = moderate probability
- -2-0 = low probability
D-dimer in detecting VTE
- sensitive test but lacks speficity
- only useful when negative
- greater than 500 ng/mL in virtually ALL patients with VTE
is contrast venography recommended as initial screening in detecting VTE
- not recommended as initial screening
- invasive
what is the preferred test in the setting of recurrent DVT
impedance plethysmography
- measures small changes in electrical resistance that reflect blood volume
what is the test of choice in detecting VTE
compression ultrasound
- detects loss of vein compressibility
- noninvasive, inexpensive
list steps you would take after getting a low probability wells criteria score
- D-dimer testing
- Negative: DVT ruled out
- positive: US
list steps you would take after getting a moderate or high probability wells criteria score
- US
- Positive: treat DVT
- Negative: D-dimer
- Negative: DVT ruled out
- Positive: repeat US in one week
treatment of DVT
- anticoagulation
- initial 5-10 days to protect from recurrent thrombosis
- long term for minimum of 3 months
- early ambulation
- compression stockings
causes of superficial thrombophlebitis
- venous cath or PICC line
- spontaneous
- hypercoagulability
clinical presentation
- dull pain in region or involved vein
- induration
- redness
- edema of extremity is uncommon
superficial thrombophlebitis
management of superficial thrombophlebitis
- NSAID
- generally subsides in 1-2 weeks
what is the most common cause of pulmonary embolism
DVT
how is PE classified
- hemodynamic stability
- temporal pattern (acute, chronic)
- anatomic location (saddle -> sub-segmental)
- symptoms (present or absent)
hemodynamic instability classification
systolic blood pressure < 90 mmHg
- **these patients are more likely to die from obstructive shoci
Name the important signs and symptoms of PE
- Dyspnea
- pleuritic pain
- cough
- tachypnea
- tachycardia
97% of patients with PE had one or more of what 3 findings
- dyspnea
- pleuritic chest pain
- tachypnea
modified wells criteria for PE: what count signifies that PE is likely?
- PE likely: > 4.0
- PE unlikely < 4.0
If you have determined “PE likely” what imaging should be done?
CT pulmonary angiogram
what was the historical “gold standard” to diagnosis PE
- pulmonary angiography
- invasive
- high IV contrast load
when would a V/Q scan be used to detect a PE? What are the downfalls to it?
- IV contrast allergy
- renal dysfunction
- sensitive but poorly specific (high # of false positives)
classic findings on EKG in PE
- sinus tachycardia
- nonspecific ST-segment and T-wave changes
- S1Q3T3 pattern
what is the alternative to sensitive D-dimer testing in patients with a low probability assessment for PE
PERC rule: PE rule out criteria
- if all 8 criteria are fulfilled, no further testing is required
VTE anticoagulants options
- IV unfractionated heparin (UFH)
- SQ low molecular weight heparin (LMWH)
- oral warfarin
- factor Xa inhibitors
- oral direct thrombin inhibitors
initial therapy for the majority of patients with VTE
- SQ LMW heparin
- SQ fondaparinux (factor Xa inhibitor)
initial therapy for the majority of patients with VTE in patients with severe renal failure and in those more likely to require rapid reversal of anticoagulation
IV UFH (unfractioned heparin)
initial therapy for the majority of patients with VTE in pregnant patients and patients with malignancy
SQ LMW heparin
long term therapy for VTE anticoagulation
warfarin
what drug can be used to reverse anticoagulation after UFH and LMW heparin administration
protamine
what drug can be used to reverse anticoagulation after warfarin administration
vitamin K and fresh frozen plasma
what drug can be used to reverse anticoagulation after factor Xa inhibitors administration
nothing FDA approved
what drug can be used to reverse anticoagulation after direct thrombin inhibitor administration
idarucizumab (Praxbind)
duration of therapy for DVT if first episode
- anticoagulation for a minimum of three months
- provoked: persistent but reversible risk factors, extend anticoagulation until the risk factor is resolved
duration of therapy for DVT if recurrent episode of unprovoked DVT, in particular those with proximal DVT
indefinite anticoagulation
alternatives to anticoagulation (i.e. anticoagulation is contraindicated)
insert an IVC filter
- prevents DVt from propagating to lungs
function of thrombolytics. When is it used
- activates plasminogen to form plasmin, resulting in the accelerated lysis of thrombi
- used in unstable patients with PE
function of thrombectomy/embolectomy
mechanical device to remove clots
prophylactic measures to prevent DVT
- sequential compression devices (SCD)
- thromboembolic deterrent hose (TED)
- low dose SQ UFH or SQ LMW heparin
