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.