DVT & PE (Dikis 2024) PDF

Deep Venous Thrombosis and Pulmonary Embolism April 2024 Ashley M. Dikis, DPM, FACFAS, DABPM OBJECTIVES 01 Recognize the pathogenesis of deep venous thrombosis (DVT) and pulmonary embolism (PE) 02 Recognize the evaluation and workup of a patient with a suspected DVT or PE 03 Identify the patient at...

Deep Venous Thrombosis and Pulmonary Embolism April 2024 Ashley M. Dikis, DPM, FACFAS, DABPM OBJECTIVES 01 Recognize the pathogenesis of deep venous thrombosis (DVT) and pulmonary embolism (PE) 02 Recognize the evaluation and workup of a patient with a suspected DVT or PE 03 Identify the patient at risk for DVT and select the appropriate pre-operative prophylaxis and treatment Question Which of the following is most true regarding work-up for a suspected DVT? → D-dimer is the most useful laboratory value and should be ordered in any case of suspected DVT B. Lower extremity angiography is the most sensitive exam for diagnosis of lower extremity DVT C. Urgent venous duplex ultrasound is the preferred exam for suspected DVT D. Anticoagulants should be initiated in patients with suspected DVT, followed by exams/lab evaluation A. DEFINITIONS Thrombus A blood clot formed in situ within the vascular system of the body and impeding blood flow Thrombophelbitis Presence of thrombus within a vein accompanied by inflammation Superficial Venous Thrombosis Thrombus in superficial vein Occurs in both inherited and acquired thrombophilic states and may progress to DVT and/or pulmonary embolism (PE) Deep Venous Thrombosis (DVT) Thrombus in deep vein network More likely to migrate proximally Pulmonary Embolism (PE) Thrombus in pulmonary artery Can be fatal Venous thromboembolism (VTE) Blood clot within a vein Introduction DVT secondary to foot and ankle injury/surgery is an uncommon but potentially devastating complication Pulmonary embolism Potentially fatal Recurrent DVT 1/3 will see recurrence within 10 years Postphlebitic Syndrome Edema, pain, induration, pigment change, ulceration DVT following F&A surgery: 0.5-3.5%* 900,000 Annual incidence of DVT/PE in the US PE following F&A surgery: 0.15% Pathogenesis Most common presentations of VTE DVT of the lower extremity Pulmonary embolism Two main categories for etiology Hereditary Acquired f o y r o t His T V D s u previo Virchow’s Triad Alterations in the constituents of the blood (i.e. inherited or acquired hypercoaguable state) Status Alterations in blood flow Stasis Vascular endothelial injury Injury Pathogenesis Unprovoked DVT No known underlying cause Risk of recurrence: 15% Provoked DVT Risk factor known Risk of recurrence: 5% Pathogenesis Proximal DVT Popliteal, femoral, or iliac veins Distal DVT No proximal component Located below the knee Confined to the calf veins (peroneal, posterior, anterior tibial, and muscular veins) Pathogenesis Thigh DVT generally more severe than calf DVT 50% of thigh DVT will propagate to PE if left untreated 20-30% of calf DVT will propagate to thigh Pathogenesis Blood passes from superficial to deep veins through perforators Valves keep blood from retrograding (Thrombus usually forms at valves) Vena cava to right side of heart, then proceeds into the pulmonary arteries and lungs OBJECTIVES 01 Recognize the pathogenesis of deep venous thrombosis (DVT) and pulmonary embolism (PE) 02 Recognize the evaluation and workup of a patient with a suspected DVT or PE 03 Identify the patient at risk for DVT and select the appropriate pre-operative prophylaxis and treatment Clinical Presentation High index of suspicion necessary Symptoms include: Pain Swelling Warmth Erythema along the affected extremity Normal post-op / post-injury? Work-Up Note on Homan sign: A positive Homan sign—calf pain with the ankle dorsiflexed and the knee flexed—is neither particularly sensitive nor specific and can be positive in up to half of patients with or without a DVT Differential Diagnosis Postoperative edema/pain Ruptured Baker’s cyst Muscle or bone pathology PVD Hematoma Lymphedema CHF Timing → Data regarding timing of DVT postoperatively: ◆ 7 days (Zixuan et al) ◆ Initial peak around day 4, with second peak around day 14 (Forsh et al) ◆ Bell curve, with increased incidence around week 2 and 3 following inpatient shoulder replacement (Sweetland et al) ◆ Within first 6 weeks postop (MacDonald et al) ◆ Timing to the diagnosis of VTE was 33.1 days on average (range 7–47) (Saragas et al) Work-Up: Testing Noninvasive duplex ultrasound Reported sensitivity and specificity of more than 90% in diagnosing DVT Ordered ASAP in patients with suspected DVT But not in those with symptoms concerning for PE Work-Up: Testing D-dimer What is it? Soluble fibrin degradation product (fibrinolysis) Should I order it? Yes and no. Literature does not support use as a stand-alone test for DVT diagnosis Use in situations in which DVT in unlikely Limited value in patients with high pre-test probability Many conditions can cause elevated Ddimer levels D-dimer less than 500µg/l traditionally considered normal Consider age and other medical conditions Work-Up: Testing Most common presenting symptom for PE is dyspnea followed by chest pain and cough Referral to ED Chest x-ray Normal or near normal Computed tomography pulmonary angiogram (CTPA) Work-Up: Testing Ventilation perfusion scan Nuclear medicine scan that uses radioactive material (radiopharmaceutical, often 99mTc) to examine airflow (ventilation) and blood flow (perfusion) in the lungs V/Q scanning is mostly reserved for patients in whom CTPA is contraindicated or inconclusive (contrast or radiation), or when additional testing is needed Modern testing with greater sensitivity and specificity OBJECTIVES 01 Recognize the pathogenesis of deep venous thrombosis (DVT) and pulmonary embolism (PE) 02 Recognize the evaluation and workup of a patient with a suspected DVT or PE 03 Identify the patient at risk for DVT and select the appropriate pre-operative prophylaxis and treatment The Journal of Foot & Ankle Surgery 54 (2015) 497–507 “Routine chemical prophylaxis is not warranted in foot/ankle surgery or injuries requiring immobilization. Rather foot and ankle surgeons should attempt to stratify patients and develop a prophylaxis plan for those at high risk of VTED.” —ACFAS Clinical Consensus Panel American Orthopaedic Foot and Ankle Society (2020) “There is currently insufficient data for the American Orthopaedic Foot & Ankle Society (AOFAS) to recommend for or against routine venous thromboembolic disease (VTED) prophylaxis for patients undergoing foot and ankle surgery. Further research in this field is both necessary and encouraged.” —AOFAS Position Statement Peri-operative Prophylaxis Fundamental reason for preventing postoperative deep vein thrombosis (DVT) is to avoid clinically significant chronic venous stasis, phlebitis, and, most importantly, potentially fatal pulmonary embolism Numerous specialty society guidelines underscore the importance of postoperative venous thromboembolism prophylaxis after hip or knee arthroplasty or in the setting of hip fracture, for which there is robust literature supporting the use of such preventive measures Peri-operative Prophylaxis But what about foot and ankle surgery? Recommendations currently in use after hip and knee arthroplasty may not be safely extrapolated to foot and ankle surgery patients Wide variability in procedure type and severity Differences in postoperative immobilization protocols Peri-Operative Risk Stratification At the population level, the overall risk of VTE for patients without risk factors undergoing foot and ankle surgery is approximately 3:1000 (overall population rate of 1:1000) Risk of VTE increases to more than 4% in the presence of previous VTE history and 2 or more of the following risk factors: Obesity with a body mass index (BMI) greater than 30 kg/m2 Age greater than 40 Medical comorbidities Use of a contraceptive pill Immobilization Peri-Operative Risk Stratification May consider Hematology referral if concern for underlying coagulopathy Advanced age and bleeding disorders found to be independent risk factors for VTE after foot and ankle fracture surgery Peri-Operative Risk Stratification A generalized, overall incidence remains difficult to determine given the wide range of host factors and foot and ankle disorders and procedures Procedures thought to carry increased risk: Trauma Achilles rupture TAR Peri-Operative Risk Stratification Literature Available evidence frequently of low quality and often contradictory in its conclusions Higher-powered level I data will be necessary to definitively answer questions related to VTE prophylaxis and develop consensus for the foot and ankle population Numerous scales to assist with risk prediction exist, though accuracy is questionable, and many have not been properly validated University of California (UC) San Diego model “3 bucket model” Caprini score Padua VTE RAM Wells Criteria Peri-Operative Risk Stratification Peri-operative Prophylaxis Several different prophylactic strategies exist to attempt to prevent VTE in the foot and ankle patient, ranging from mechanical prophylaxis to chemoprophylaxis Full anticoagulation is generally reserved for once the patient has developed a DVT or PE “Full” meaning full dose with goal of therapeutic as opposed to prophylactic degree of anticoagulation Aspirin MOA: Inhibits cyclooxygenase-1 and 2 (COX-1 and 2) enzymes, ultimately leading to inhibition of platelet aggregation Evidence: Currently insufficient to support the use of aspirin after foot and ankle surgery Hip and knee arthroplasty Limited evidence exists specifically for the foot and ankle population Aspirin Dosage: 81mg BID – 325mg BID Mixed results in literature for low vs high dose Cardiology literature has demonstrated an equivalent cardioprotective effect of lower dose (81 mg) vs higher dose (325 mg) Notably, as compared with other blood thinners, it may have a lower rate of adverse events, such as bleeding or wound complications postoperatively Low Molecular Weight Heparin (LMWH) MOA: Indirect inhibition of factor Xa Evidence: Mixed regarding the use of LMWH after lower leg injury or surgery The AOFAS consensus panel recommends that if considering LMWH following a foot or ankle surgery, therapy should begin when immobilization is initiated and continued for the duration of immobilization, with non–weight-bearing status recognized as a modifiable risk factor, but without specific recommendation for starting chemoprophylaxis Low Molecular Weight Heparin (LMWH) Dosage: Lovenox (enoxaparin) 40mg subcutaneous injection once daily Lovenox (enoxaparin) 30mg subcutaneous injection twice daily Risk of developing heparin-induced thrombocytopenia (HIT), a potentially fatal complication from an immunologic process Carries less risk than unfractionated heparin Presenting symptoms include hemodynamic instability with fevers, tachycardia, hypertension, diaphoresis, chills, dyspnea, and chest and abdominal pain Unfractionated Heparin (UFH) MOA: Binds to antithrombin III which potentiates the inhibition of thrombin (II) and Xa, IXa, XIa, XIIa Inactivates thrombin by cofactor II which acts independently of ATIII Dosage: 5000 U subcutaneous TID Short half-life Can be reversed with protamine sulfate Unfractionated Heparin (UFH) Benefits of LMWH over UFH: Administered subQ bid/daily Much less bleeding and virtually no thrombocytopenia No lab monitoring More predictable pharmacodynamics Coumadin Has been almost completed replaced by other agents Requires bridge therapy Peak effect 24-72 hours Requires routine INR Many drug and food interactions Other chemoprophylaxis Per AOFAS panel, when subcutaneous injections such as LMWH are not an option in the outpatient setting (eg, patient intolerance or nonadherence) and chemical prophylaxis is desired, warfarin with a targeted international normalized ratio (INR) 2.5 (acceptable range 2.0–3.0) or newer oral agents such as apixaban, dabigatran, or rivaroxaban that do not require INR monitoring are viable options Apixaban = Eliquis Dabigatran = Pradaxa Rivaroxaban = Xarelto IVC Filter Greenfield filter May be considered when contraindications to chemical prophylaxis exist, such as head injury or severe hemodynamic instability There is no specific evidence in the use of IVC filters for foot and ankle surgery, and the IVC filter efficacy for patients without a prior history of DVT is not well established So you’ve diagnosed a DVT… …now what? Decision for inpatient or outpatient management Most can be managed outpatient, except: Massive DVT (eg, iliofemoral DVT) Concurrent symptomatic pulmonary embolism (PE) High risk of bleeding on anticoagulant therapy Comorbid conditions or other factors that warrant in-hospital care DVT management In most situations, some form of treatment will be indicated: Oral chemoprophylaxis Eliquis Xarelto LMWH or heparin Coumadin with heparin bridge The American College of Chest Physicians (ACCP) 2012 guidelines suggest for acute isolated distal DVT without severe symptoms or risk factors to perform serial imaging of the deep veins for 2 weeks. Only if patients have severe symptoms or risk factors, then anticoagulation should be initiated. DVT management Thrombolytics rarely indicated Does not seem to decrease incidence of PE Preserve venous valves Decrease risk of developing postphlebitic syndrome Thrombectomy seldom performed Summary Although the risk in aggregate of VTE in the foot and ankle population remains lower than the overall risk identified in the hip and knee population, it has yet to be properly defined Additional large-scale, prospective studies are needed Studies exist recommending against the use of prophylaxis, yet majority of providers continue to prescribe routinely If considering the use of chemical prophylaxis, LMWH is effective at reducing the rate of clinically significant VTED and appears to be the most studied agent in current literature Summary Risk factors for development of VTE Clinical presentation Work-up for suspected DVT or PE Perioperative prophylaxis Who What Treatment for DVT Remember—there aren’t any easy answers to these questions. You ultimately have to use your best judgement and available information Question Which of the following is most true regarding work-up for a suspected DVT? → D-dimer is the most useful laboratory value and should be ordered in any case of suspected DVT B. Lower extremity angiography is the most sensitive exam for diagnosis of lower extremity DVT C. Urgent venous duplex ultrasound is the preferred exam for suspected DVT D. Anticoagulants should be initiated in patients with suspected DVT, followed by exams/lab evaluation A. Clinical Takeaways: Identify risk factors: I always ask about previous DVT and family history of DVT or bleeding disorder Discuss plans for anticoagulation based on risk factors and type of surgery being performed Often decision is made based on need for NWB postoperatively in addition to presence of risk factors (consider scale/criteria to assist) Common choices include Lovenox 40mg subq once daily Xarelto 10mg PO once daily Eliquis 2.5 PO BID Aspirin? Consider renal status and risk factors for bleeding event Duration of treatment will vary based on risks and NWB status Reach out to PCP or Hematology for additional guidance as needed REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Chien et al. Venous Thromboembolism Disease Prophylaxis in Foot and Ankle Surgery. Orthop Clin N Am 49 (2018) 265–276. Fleischer et al. American College of Foot and Ankle Surgeons’ Clinical Consensus Statement: Risk, Prevention, and Diagnosis of Venous Thromboembolism Disease in Foot and Ankle Surgery and Injuries Requiring Immobilization. J Foot Ank Surg 54 (2015) 497–507. Weisman et al. Venous Thromboembolic Prophylaxis in Foot and Ankle Surgery: A Review of Current Literature and Practice. Foot Ankle Spec 2017 Aug;10(4):343-351. Uptodate – “Overview of the treatment of lower extremity deep vein thrombosis (DVT)” and “Overview of the causes of venous thrombosis” Deep vein thrombosis and pulmonary embolism [PowerPoint 2021] Courtesy of Erin Nelson, DPM. Saragas et al. The impact of risk assessment on the implementation of venousthromboembolism prophylaxis in foot and ankle surgery. Foot Ank Surg 2014; 20: 85-89. Forsh et al. Deep Venous Thrombosis Prophylaxis in Orthopedic Surgery, 2021. Sweetland et al. Duration and magnitude of the postoperative risk of venous thromboembolism in middle aged women: prospective cohort study. BMJ 2009. Weitz, J, Fredenburgh, J, Eikelboom, J. A Test in Context: D-Dimer. J Am Coll Cardiol. 2017 Nov, 70 (19) 2411–2420. https://doi.org/10.1016 /j.jacc.2017.09.024 Brennan et al. Postoperative venous thromboembolism risk=prediction in foot and ankle fracture surgery. The Foot 56 (2023) 1-6. THANKS! This presentation may contain copyrighted material used for educational purposes under the guidelines of Fair Use and the TEACH Act. It is intended only for use by students enrolled in this course. Reproduction or distribution is prohibited. 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