Please confirm topic selection

Are you sure you want to trigger topic in your Anconeus AI algorithm?

Please confirm action

You are done for today with this topic.

Would you like to start learning session with this topic items scheduled for future?

Updated: Sep 21 2023

Thromboembolism (PE & DVT) Prophylaxis

Images
https://upload.orthobullets.com/topic/9056/images/coagulation cascade aaos_moved.jpg
https://upload.orthobullets.com/topic/9056/images/a9dbf3b4-1d0b-45a5-92c0-bf69623ef7cf_ctpa_showing_saddle_embolus.jpg
https://upload.orthobullets.com/topic/9056/images/db5f8782-dc73-4e52-90f4-effee82d9b57_vq_scan_showing_bilateral_major_miscmath_defect_consistent_with_high_probability_of_pulmonary_embolism.jpg
https://upload.orthobullets.com/topic/9056/images/a7ea2722-4904-4ca2-b36b-8fa508d47c60_dvt_us.jpg
  • Summary
    • Venous thromboembolism (VTE) includes both pulmonary embolism (PE) and deep venous thrombosis (DVT)
    • Diagnosis is generally made with clinical exam and imaging to include ultrasound for extremity DVT and CT chest for pulmonary embolism
    • Treatment is pharmacologic blood thinners 
  • Epidemiology
    • Incidence
      • incidence
        • DVT
          • 200,000 per year in the US
        • PE
          • 50,000 per year in the US
    • Risk factors 
      • Virchow's triad
        • venous stasis
        • hypercoagulable state
        • intimal injury
      • primary hypercoagulopathies (inherited)
        • MTHFR/C677T/TT gene mutation carries the highest risk
        • factor V Leiden mutation
        • antithrombin III deficiency
        • protein C deficiency
        • protein S deficiency
        • activated protein C resistance
        • elevated factor VIII
        • hyperhomocysteinemia
        • prothrombin II G20210A
      • secondary factors (acquired)
        • malignancy
          • recently been associated with up to 20% of all new diagnoses of VTE
        • elevated hormone conditions
          • recombinant erythropoeitin
          • hormone replacement
          • oral contraceptive therapy
          • late pregnancy
        • elevated antiphospholipid antibody conditions
          • lupus anticoagulant
          • anticardiolipin antibody
        • medical history
          • history of thromboembolism
          • obesity
          • CHF
          • varicose veins
          • smoking
          • increased blood viscosity
          • thoracic outlet syndrome (upper extremity DVT)
        • other
          • general anesthetics (vs. epidural and spinal)
          • rapid increase in INR following unopposed initiation of warfarin therapy in arthroplasty patients
            • hypothesized to occur due to the warfarin-induced decline in protein C occurring before warfarin's antithrombotic effect occurs (protein C has a half-life of 6-8 hours and factor II has a half-life of 48-120 hours).
      • no increase in DVT has been associated with the use of tranexamic acid (TXA)
      • increasing incidence of pediatric VTE due to obesity, contraceptives, smoking, etc.
  • Etiology
    • Pathophysiology
      • Mechanism of clot formation
        • stasis
        • fibrin formation
          • thromboplastin (aka Tissue Factor (TF), platelet tissue factor, factor III) is released during dissection which leads to activation of the extrinsic pathway and fibrin formation
        • clot retraction
        • propagation
  • Anatomy
    • DVT usually begins in venous valve cusps.
    • Thrombi consist of thrombin, fibrin, and RBCs with relatively few platelets.
  • Classification
    • Acute DVT
      • clots are developing or have recently developed within 28 days
    • Chronic DVT
      • persists more than 28 days
      • an episode of VTE after an initial one is classified as recurrent.
  • Presentation
    • Symptoms of DVT
      • calf pain
      • palpable cords
      • pitting extremity swelling
        • 50% with classic signs have no DVT
    • Symptoms of PE
      • most PEs are asymptomatic     
      • symptoms
        • pleuritic chest pain                             
        • dyspnea                              
        • tachypnea                                
        • large PEs (e.g., saddle emboli) can present as death though
  • Imaging
    • Radiographs
      • recommended views
        • 2 view chest (PA and lateral)
      • findings
        • early findings
          • usually normal but may present with
            • “oligemia” 
            • prominent hilum 
        • late findings
          • wedge or platelike atelectasis 
    • Duplex compression ultrasound
      • recommended views
        • should be ordered on the extremity of concern in a symptomatic patient
        • gold standard for diagnosis of DVT
        • there is a strong AAOS recommendation against routine postoperative duplex screening in elective arthroplasty cases in an asymptomatic patient 
      • findings
        • "noncompressible vein"
          • 95% sensitive/specific
        • 50% with venogram positive for clot have normal physical findings 
        • no indication for routine duplex screening
    • CT pulmonary angiography
      • indications
        • gold standard for diagnosis of PE
    • Ventilation-perfusion scan
      • indications
        • helpful for contrast-allergy patients
  • Studies
    • Labs
      • d-dimer
        • can be helpful in ruling out a significant clot.
        • not as helpful after injury/surgery  
    • EKG
      • indication
        • rule out MI
      • findings
        • most common finding is sinus tachycardia.
  • Treatment
    • Prophylaxis
      • indications
        • prevention of deep vein thrombosis (DVT) and pulmonary embolism (PE) is most important factor in decreasing morbidity and mortality
        • the use of pharmacologic prophylaxis and mechanical compression received a moderate strength recommendation from the AAOS
        • prophylaxis treatment should be determined by weighing risk of bleeding vs risk of pulmonary embolus
          • AAOS risk factors for major bleeding
            • bleeding disorders
            • history of a recent gastrointestinal bleed
            • history of a recent hemorrhagic stroke
          • AAOS risk factors for pulmonary embolus
            • hypercoagulable state
            • previous documented pulmonary embolism
          • DVT prophylaxis is recommended for all hip/knee arthroplasty patients 
          • For standard patients, DVT prophylaxis is NOT recommended for following
            • upper extremity procedures
            • arthroscopic
            • isolated fractures at knee and below
    • Treatment of VTE
      • serial US scans
        • indications
          • isolated calf thrombosis smaller than 5 cm rarely needs treatment.
      • pharmacologic treatment
        • duration
          • approximately 3 months after DVT
          • approximately 12 months after PE
      • early mobilization
        • risk of dislodgment less than risk of more clots in these high-risk patients
      • graduated elastic compression hose 
        • may prevent postthrombotic syndrome
      • thrombolytics, thrombectomy, embolectomy
        • indications
          • controversial
  • Techniques
    • Pharmacologic agents
    • Hip & Knee Arthroplasty Prophylaxis
      • indication
        • VTE prophylaxis recommended for all THA and TKA patients
          • AAOS and American College of Chest Physicians developed guidelines but do not recommend an optimal regimen; an individualized ppx regimen balancing efficacy and safety based on risk factor should be implemented
      • techniques
        • mechanical prophylaxis
          • compressive stockings recommended
          • pneumatic compression devices are recommended by the AAOS across all risk (low to high risk of either bleeding or pulmonary embolism) groups undergoing total hip or total knee arthroplasty
            • increase venous return and endothelial-derived fibrinolysis
            • decrease venous compliance and venous stasis
        • chemoprophylaxis
          • American Academy of Orthopaedic Surgeons (AAOS) and American College of Chest Physicians (ACCP) support ASA as a monotherapy
    • Spine Surgery Prophylaxis
      • indication
        • no clear consensus regarding utilization or timing of VTE prophylaxis measures after spine surgery
        • risks of VTE must be weighed against postoperative bleeding and epidural hematoma formation
        • patients with a spinal cord injury and prolonged immobilization are at increased risk
      • technique
        • early mobilization is recommended, along with pneumatic compression devices
        • chemoprophylaxis
          • longer surgical times
          • multilevel thoracolumbar surgery
          • anterior thoracolumbar approaches
    • Shoulder Arthroplasty Prophylaxis
      • indication
        • early mobilization, mechanical prophylaxis, regional anesthesia
        • LMWH/heparin until ambulatory if increased risk, not for routine use in UE surgery
    • Foot & Ankle Surgery Prophylaxis
      • the risk of VTE was not found to be lowered by thromboprophylaxis in a study of 20,043 adult patients
    • Trauma prophylaxis
      • mechanical and chemoprophylaxis lower the rate of DVT and PE
  • Complications
    • DVT complications
      • pulmonary embolism (PE)
      • chronic venous insufficiencypost-thrombotic syndrome.
      • post-thrombotic syndrome.
        • incidence
          • post-thrombotic syndrome occurs in 43% two years post-DVT (30% mild, 10% moderate, and severe in 3%). 
    • PE complications
      • sudden cardiac death
      • obstructive shock
      • pulseless electrical activity
      • atrial or ventricular arrhythmias
      • secondary pulmonary arterial hypertension
      • cor pulmonale
      • severe hypoxemia
      • right-to-left intracardiac shunt.
    • Recurrence
      • incidence 
        • risk of recurrence of DVT is 25%.
  • Prognosis
    • Many DVTs will resolve with no complications.
    • Death occurs in
      • 6% of DVT cases within 1 month of diagnosis
      • 12% of PE cases within 1 month of diagnosis.
    • Approximately 10% of patients who develop PE die within the first hour, and 30% die subsequently from recurrent embolism.
Card
1 of 75
Question
1 of 26
Private Note