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Deep Venous Thrombosis TURANDOT SAUL, M.D. SEPTEMBER 12TH, 2007 ST. LUKE’S ROOSEVELT HOSPITAL DEPARTMENT OF EMERGENCY MEDICINE Virchow Triad • Venous stasis • Vessel wall injury • Hypercoagulable state Incidence Likely underestimated - Misdiagnosis - Occult resolve without complication - Non-occlusive - Venous collaterals develop rapidly Risk Factors General - Age - Immobilization > 3d - Pregnancy / post-partum - Major surgery < 4 weeks - Trip (>4h) in past 4 weeks Medical - Cancer - Previous DVT - CHF - Sepsis - Nephrotic syndrome Trauma - CNS / spinal cord injury - Burns - Lower extremity fractures Hematologic - Thrombocytosis - Anti-thrombin III deficiency - Protein C deficiency - Protein S deficiency - Factor V Leiden Drugs - OCP - Estrogens The Life of a Clot… Valve cusps of deep calf veins - Dissolve - Adherence and Organization - 5-10 days - Propagate - Embolize - Chronic Venous Insufficiency History and Physical Edema Leg pain Tenderness Superficial thrombophlebitis - Increased risk of DVT Fever Alternate Diagnosis Achilles tendinitis Lymphedema Arterial insufficiency Muscle / soft tissue injury Arthritis Neurogenic pain Cellulitis / lymphangitis Postphlebitic syndrome Extrinsic vein compression Ruptured Baker cyst Hematoma Fracture / bony lesions Superficial thrombophlebitis Wells Clinical Score for DVT Clinical Parameter Score Active cancer +1 Paralysis or recent immobilization of extremities +1 Recently bedridden for > 3 days or major surgery <4 weeks +1 Tenderness along distribution of deep venous system +1 Entire leg swollen +1 Calf swelling > 3cm circumference difference from unaffected leg +1 Pitting edema +1 Previous DVT +1 Collateral superficial veins +1 Alternative diagnosis as likely or more likely than DVT -2 High Probability ≥3 Moderate Probability 1 or 2 Low Probabillity 0 D-dimer Fragments - Degradation of fibrin by plasmin Elevated in any condition where clots form - Trauma, recent surgery, cancer, sepsis Low specificity - r/o DVT Elevated for 7 days Who Should We Study? Imaging Studies Study Notes Contrast Venography - “Gold standard”, 99% sensitive - Allergic reaction, availability, IV contrast, costly - Good for calf, iliac veins, IVC MRI - Useful in pregnancy - Can distinguish acute from chronic - Good for calf, iliac veins - Cost, accessibility CT - Can do PE study at same time - Good for calf, iliac veins Duplex Ultrasonography - No radiation, bedside, cost - Non-occlusive thrombi - Cannot distinguish acute from chronic - Poor visualization of calf, iliac veins Lower Extremity Venous Anatomy External Iliac Common Femoral Vein - Deep femoral vein - Superficial Femoral Vein - Popliteal Vein - Anterior Tibial Vein - Posterior Tibial Vein - Peroneal Vein Some Logistics High frequency linear array probe (7-10MHz) Head of bed to 45⁰ Patient Positioning What is Duplex Ultrasound? B-mode Imaging + Doppler Ultrasound Doppler Ultrasound: Color Doppler Ultrasound: Spectral Ultrasound for DVT Major criterion - Failure to compress vascular lumen - Not visualization of lumen - Acute thrombus can be anechoic - Slow flowing blood can have internal echoes Minor criterion - Absence of normal doppler signals - Absence of flow - Absence of respiratory variation in flow - Decreased augmentation with distal compression - Distension of vessel Major Criteria: Compressibility Collapse of lumen of vein - Complete apposition of anterior and posterior wall Compress with transducer in transverse - Longitudinal compression slides off vessel wall leading to false negative - Use to follow course of vein May visualize thrombus; not necessary for diagnosis Compressibility: Normal Findings A A V Compressibility: DVT A V A V Compressibility Ultrasound for DVT Major criterion - Failure to compress vascular lumen - Not visualization of lumen - Acute thrombus can be anechoic - Slow flowing blood can have internal echoes Minor criterion - Absence of normal doppler signals - Absence of flow - Absence of respiratory variation in flow - Decreased augmentation with distal compression - Distension of vessel Minor Criteria: Flow Minor Criteria: Respiratory Variation Minor Criteria: Respiratory Variation Minor Criteria: Augmentation Femoral Vein Begin at inguinal ligament Distally bifurcates into superficial and deep femoral veins Compression in Hunter’s canal difficult because of depth Femoral Vein Popliteal Positioning Vein superficial to artery Scan to trifurcation point Popliteal Diagnostic Difficulties False negatives - Adductor canal - Complete occlusion - Ilio-femoral DVT - Duplicated vessels - Technical difficulties - obese patients - significant lower extremity edema False positives - Chronic vs. acute - Proximal obstruction limits compressibility - Superficial vein filled with thrombus Operator Dependence How Good is it? Noninvasive Diagnosis of Deep Venous Thrombosis - Large review of US for DVT - Proximal DVT: sensitivity 95%, specificity 96% - Calf vein DVT: great variation - Overall: sensitivity 89%, specificity 94% -Kearon C, et al. Limited Ultrasound Image entire venous system - Technically difficult - Time Limited Ultrasound - Only B-mode compression - 5 cm inguinal ligament - 5 cm popliteal fossa How Good is Limited Ultrasound? Detection of Deep Vein Thrombosis by B-mode Ultrasonography - Sole criterion was compressibility of common femoral or popliteal vein - 100% sensitive for proximal DVT - 91% sensitive overall -Lensing, et.al. How Good is Limited Ultrasound? Limited B-mode venous Imaging Versus Complete Color-flow Duplex Venous Scanning for Detection of Proximal Deep Venous Thrombosis - time reduction 37 minutes vs. 5.5 minutes - Poppiti et.al. Are DVT in calf veins ok? Smaller Propagate Treatment? Do You Study the Asymptomatic Leg? Unilateral symptoms - risk in contralateral leg is <1% Assist in difficult anatomic interpretations Does it matter if anti-coagulating anyway? Other Ultrasound Diagnosis Lymph node Baker’s cyst Superficial thrombophlebitis Popliteal artery aneurysm Lymph Node LN A Baker Cyst Popliteal Artery Aneurysm Upper Extremity DVT Massive PE extremely rare Lower incidence - Fewer venous valves - Higher flow rate - Less frequent immobility - Decreased hydrostatic pressure - Malignancy, catheter induced Clavicle prohibits adequate compression - Evaluate using color or spectral Doppler What Happens to the Clot? Clot retracts and becomes echogenic Vein wall becomes thickened, echogenic and resistant to compression In 12-24 months, 50% have complete resolution of thrombus and normal compressibility Difficult to evaluate acute vs. chronic - Post-treatment baseline study for comparison Data Forms and Worksheets? Thank You Dr. Resa Lewiss The Ultrasound Division Resources Ultrasound diagnosis of deep venous thrombosis. Tracy JA - Emerg Med Clin North Am - 01-AUG-2004; 22(3): 775-96 Cecil Textbook of Medicine, 22nd ed. Rosen's Emergency Medicine: Concepts and Clinical Practice, 6th ed. Birdwell BG, Raskob GE, Whitsett TL, et al. The clinical validity of normal compression ultrasonography in outpatients suspected of having deep venous thrombosis. Ann Intern Med 1998;128:1-7. Lensing AW, Prandoni P, Brandjes D, et al. Detection of deep-vein thrombosis by real-time B-mode ultrasonography. N Engl J Med 1989;320:342-5. Poppeti R, Papanicolaou G, Perese S, et al. Limited B-mode venous imaging versus complete color-flow duplex venous scanning for detection of proximal deep venous thrombosis. J Vasc Surg 1995;22:553-7. Kearon C, Julian JA, Newman TE, et al. Noninvasive diagnosis of deep venous thrombosis. McMaster Diagnostic Imaging Practice Guidelines Initiative. Ann Intern Med 1998;128:663-77. http://www.vascularweb.org/graphics/northpoint_graphics_jpg/DVT_01_Base_275.jpg http://radiology.muhealth.org/new_Radiology_Web/Interventional/irImages/DVT_normal_and_embolus http://www.imvs.sa.gov.au/dvt_likelihood.gif http://www.imvs.sa.gov.au/dvt_likelihood.gif http://www.vascularweb.org/graphics/northpoint_graphics_jpg/DuplexUltra_02REV_Base_300.jpg http://www.thieme-connect.com/ http://www.iame.com/learning/upExtVen/figure1t.gif http://www.dvthealth.com/dvt_exerciser.htm