SM_258b: Thrombotic Disorders Flashcards
Venous thrombosis is ___
Venous thrombosis is an occlusive clot in a vein
- DVT is blood clot in veins in legs / arms
- Pulmonary embolus: migrating thrombosis (clot) that travels to pulmonary artery, often embolizes from DVT of leg
- Superficial veins of arms and legs: superficial vein thrombosis, superficial thrombophlebitis
- Other locations
Describe rates of embolism from DVT to PE
Rates of embolism from DVT to PE
- Proximal lower extremity DVT: 50%
- Distal lower extremity DVT: 10-15%
- Upper extremity DVT: 6-10%
In erect position, blood is propelled ____, while backflow is prevented by an extensive system of ____
In erect position, blood is propelled proximally from calf veins by muscular action, while backflow is prevented by an extensive system of valves
While valves prevent blood pooling distally, there is ___
While valves prevent blood pooling distally, there is increased turbidity within the valve sinus potentially stimulating thrombus formation
- Procoagulant factors: vWF
- Anticoagulant factors: endothelial protein C receptor (EPCR), thrombomodulin (TM)
Proximal DVT is proximal to the ___
Proximal DVT is proximal to the popliteal vein
Describe VTE nomenclature
VTE nomenclature
- Temporal pattern: based on symptoms and imaging characteristics, acute (immediate to days), subacute (weeks), chronic
- Anatomic location: PE (saddle, lobar, segmental, subsegmental), VTE of extemities (superficial vs deep, deep is proximal vs distal)
Describe categories of PE
PE categories
- Massive: hemodynamically unstable: shock
- Submassive: associated right ventricular strain without hemodynamic instability
- Signs of RV strain: RV systolic dysfunction or RV dilation on echo, RV/LV > 0.9 or flattening of septum or paradoxical spetal bowing on CT scan, elevated BNP and troponin
DVT usually presents with ___, ___, ___, and ___
DVT usually presents with pain, unilateral swelling, warmth, and redness
PE presents with ____ and ____
PE presents with dyspnea and pleuritic chest pain
Describe Wells criteria for DVT and PE
Wells criteria for DVT and PE
Plasma D-dimer is a ___
Plasma D-dimer is a cross-linked fibrin degradation product that increases up to 8-fold in VTE
- Non-specific: also increases with age, pregnancy, renal failure, and malignancy
- Used in conjunction with pre-test probability in diagnostic workup
Describe lab / imaging diagnosis of DVT / PE
Lab / imaging diagnosis of DVT / PE
- DVT: D-dimer, Duplex US, venography, MRI
- PE: D-dimer, CTA, pulmonary angiography
- V/Q scan, echo
Describe compression US for DVT
Compression US for DVT
- Venous pressure rises when vein is occluded by thrombus and becomes incompressible
- Echogenic material within lumen may suggest presence of thrombus
- Good for thrombi in common femoral, superficial, and popliteal veins
- Not as good for thrombi in distal veins of calf and pelvic veins
___ is gold standard for diagnosis of PE
Pulmonary angiogram is gold standard for diagnosis of PE
30 yo woman with Hx of anxiety presents to ER with concern of RLE swelling that has progressed over past 2 weeks, which started day after returning from driving home for Florida. Taking OCPs.
Wells score is ___
Then, get ____
D-dimer is 700 so get ____
30 yo woman with Hx of anxiety presents to ER with concern of RLE swelling that has progressed over past 2 weeks, which started day after returning from driving home for Florida. Taking OCPs.
Wells score is 2 (intermediate)
Then, get D-dimer
D-dimer is 700 so get RLE US Doppler
Incidence of VTE increases with ___
Incidence of VTE increases with age
- Blacks more likely to die
Virchow’s triad is ___, ___, and ___
Virchow’s triad is endothelial injury, abnormal blood flow, and hypercoagulability
Threshold model of VTE is ___
Threshold model of VTE is risk increases above a threshold with inherited or acquired risk factors
- Inherited thrombophilia
- Acquired risk factors: advanced age, obesity, cancer, immobility
- Triggering factors: surgery, pregnancy, hormonal therapy
Trousseau’s syndrome is ___
Trousseau’s syndrome is thrombophlebitis migrans may be a sign of abdominal cancer
Describe mechanism of cancer-related VTE
Cancer-related VTE mechanism
- Tissue factor is expressed by tumor
- Tumor release of procoagulants
- Tumor compression of vessels
Tumor types with highest risk of VTE are ____, ____, ____, and ____
Tumor types with highest risk of VTE are primary brain, pancreatic, stomach, and lung cancer
- Tumor type is associated with risk of VTE
Thrombophlebitis, recurrent thrombus, and thrombi in unusual locations may indicate ___
Thrombophlebitis, recurrent thrombus, and thrombi in unusual locations may indicate cancer-related VTE
May-Thurner syndrome is ___
May-Thurner syndrome is chronic compression of the L common iliac vein between the overlying R common iliac artery and first vertebral body
- Associated with VTE
Venous thoracic outlet syndrome (Paget-Schroetter syndrome) is ___
Venous thoracic outlet syndrome (Paget-Schroetter syndrome) is axillary-subclavian DVT associated with strenuous or repetitive activity
VTE is treated with ___ and ___
VTE is treated with anticoagulation and thrombolysis
- Anticoagulation: balance risk of VTE and risk of bleeding, duration of anticoagulation depends on risk factors for clot
- Thrombolytic therapy: systemic thrombolysis, catheter-directed thrombolysis, thrombectomy
IVC filter indications are ___
IVC filter indications are acute PE or proximal DVT and inability to use therapeutic anticoagulation
- Potential complications: acute clot (PE, DVT), distal obstruction, perforation, embolization
Complications of VTE are ___, ___, ___, and ___
Complications of VTE are death, recurrent thrombosis, post-thrombotic syndrome, and pulmonary hypertension (CTEPH)
- Risk of recurrence greatest closer to event, higher in men
Post-thrombotic syndrome is when ____, leading to ____ and ____
Post-thrombotic syndrome is when venous occlusion by thrombi increase venous pressure (venous hypertension) and result in venous distension, leading to incompetent valves and reflux
Describe consequences of post-thrombotic syndrome
Post-thrombotic syndrome consequences
- Symptoms of pain, paresthesia, sensation of heaviness, residual swelling
- Signs of chronic venous insufficiency: discoloration of leg, ulcers, dilated veins
- Can result in permanent disability
- No good treatment options
Chronic thromboembolic pulmonary hypertension is when ___
Chronic thromboembolic pulmonary hypertension is when pulmonary vasculature becomes attenuated due to vessel wall thickening and luminal narrowing
- Risk factors: younger age, previous PE, large perfusion defects, idiopathic presentation
Chronic thromboembolic pulmonary hypertension presents with ____, ____, ____, and ____
Chronic thromboembolic pulmonary hypertension presents with dyspnea, fatigue, anorexia, and hemoptysis
Chronic thromboembolic pulmonary hypertension treatment involves ____ and ____
Chronic thromboembolic pulmonary hypertension treatment involves chronic anticoagulation and thromboendarterectomy in severe cases
Describe VTE prevention
VTE prevention
- During hospitalization: mobility, mechanical, pharmagoloci thromboprophylaxis
- Extended thromboprophylaxis
