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Venous Thromboembolism

Venous Thromboembolism. Core Rounds April 10, 2003 A.F. Chad, MD, CCFP. DVT Objectives. Epidemiology Natural History Risk Factors Hx & PHx & Pre-test Probability Wells & Perrier Tests (D-dimer, Doppler, IPG, Venography) Upper Extremity DVT (Dx, RF, Rx, risk PE) Rx.

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Venous Thromboembolism

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  1. Venous Thromboembolism Core Rounds April 10, 2003 A.F. Chad, MD, CCFP

  2. DVT Objectives • Epidemiology • Natural History • Risk Factors • Hx & PHx & Pre-test Probability • Wells & Perrier • Tests (D-dimer, Doppler, IPG, Venography) • Upper Extremity DVT (Dx, RF, Rx, risk PE) • Rx

  3. DVT: Submission move by Jake “The Snake” Roberts OR Badness in the Veins?

  4. Epidemiology • Lifetime incidence VTE 2-5% • PE: 0.5/1,000/year • DVT: 1/1,100/year • Prospective studies of DVT: • 10-13% medical pts on bed rest 1 week • 29-33% pts in ICU • 20-26% pts pulmonary diseases given bed rest >3d • 27-33% CCU pts • 48% pts post CABG

  5. History • 1550 BC: Ebers papyrus documented peripheral venous disease • 1644 Schenk observed venous thrombosis with occlusion in the IVC • 1846 Virchow -> association b/n venous thrombosis in legs & PE • 1937: Heparin comes into practice

  6. Natural History • 19th C Virchow’s triad: venous stasis, injury to intima, hypercoagulability • Thrombosis: platelet nidus near venous valves->platelets and fibrin -> thrombus -> occlusion, embolism • Endogenous thrombolytic system -> partial dissolution-> organized into venous wall

  7. Natural History • Most go away w/o Rx • 20% propagate proximally • Organize into vein by day 5-10 • Biggest risk of propagation, embolization is before this

  8. Natural History • Debate whether isolated calf thrombi are important • Some said to have low risk PE • Others said just as bad

  9. Risk Factors: General • Age • Immobilization longer than 3 days • Pregnancy and the postpartum period • Major surgery in previous 4 weeks • Long plane or car trips (>4-6 h) in previous 4 weeks • Wrestling Jake “The Snake” Roberts

  10. Medical Cancer,Previous DVT, stroke, MI, CHF, sepsis, nephrotic, UC Trauma Multiple trauma, CHI, SCI, Burn, LE # Vasculitis SLE / LAC, Bechet, Homocystinuria Hematologic PRV, Thrombocytosis Clotting D/O Antithrombin III , Protein C, Protein S, Factor V Leiden, Dysfibrinogenemias and disorders of plasminogen activation Drugs/medications IV drug abuse Oral contraceptives Estrogens HIT Risk Factors: Specific

  11. Risk Factors • 50% without risk factors • OCP/HRT: 3x baseline risk • 0.3/10,000/yr; 15/10,000/yr • higher in 3rd gen progesterones • pregnancy: 5x baseline risk • 75% DVT antepartum, 66% PE postpartum

  12. Pathophysiology:Source of VTE • most start in calf, extend proximally • 70% PE have DVT evidence at autopsy • 70-90% known source: IVC, ileofemoral or pelvic veins, 10-20% SVC • incidence of PE from DVT • calf: 46% • thigh: 67% • pelvic: 77% • other: UE, jugular, mesenteric, cerebral

  13. History • Many No Sx • Edema (unilateral) specific • Leg pain in 50% -> nonspecific • Tenderness in 75%, but also in 50% w/o DVT • 10% Sx PE • Amount pain / tenderness do not correlate to severity • Warmth, erythema

  14. Physical • No ONE reliable history / physical finding • Sensitivity 60-96%, Specificity 20-72% • Need to look @ combination of factors • Anand SS, Wells PS, Hunt D, Brill-Edwards P, Cook D, Ginsberg JS. Does this patient have deep vein thrombosis? JAMA. 1998 Dec 2;280(21):1828-9.

  15. Physical • Edema (unilateral) (> 3cm) • Homan’s (50% sens) • Superficial thrombophlebitis (up to 40% can have) • Fever (>39.5, something else) • Phlegmasia cerulea dolens • Swollen purple leg re venous engorgement • Cyanosis re massive venous obstruction • Phlegmasia alba dolens • Whitish inflammation associated with arterial spasm 2nd to massive venous obstruction • Worry about arterial occlusion

  16. Clinical Presentation:DVT • Calf-popliteal • 80-90%, many asymptomatic • pain & swelling • 10-20% spreads proximally • Ileofemoral • pain in buttock, groin • thigh swelling • 10-20% cases • Do not adhere to vessel walls until 5-10d post formation -> high risk to propagate / embolize

  17. Clinical Prediction Model for DVTWells et al. Ann Int Med, 1997

  18. Clinical Model for DVT

  19. Incidence of DVT by Clinical Probability

  20. Algorithm for Suspected first DVT:Perrier. Lancet, 1999

  21. Tests • D-dimer • Doppler U/S • IPG • Venography

  22. D-Dimer • Not “Clot specific” • recent surgery, trauma, MI, pregnancy, CA can all give false +

  23. D-dimer AssaysVan der Graaf. Thromb Haemost, 2000.

  24. Diagnostic Imaging for DVT • Duplex / compression U/S • non-invasive, portable • direct visualization of veins and flow • loss of compression = DVT • 97% sensitive & specific for symptomatic proximal/popliteal DVT • 62% sensitive for asymptomatic DVT • +ve in 30-50% PE; 5% non-dx V/Q scans

  25. Serial Venous U/S • 2 protocols: Wells & Hull • may avoid angiography in ?PE • 2% +ve in 2 weeks (?PE) • if U/S -ve 2 weeks apart, <2% have VTE in next 6 mos

  26. Diagnostic Imaging for DVT • IPG • detects changes in flow before and after cuff inflated • sensitivity 60%

  27. IPG vs. Doppler • N=985 • PPV U/S=94% (CI 87-98%) • PPV IPG =83% (CI 75-90%) • P=0.02 • Harriet Heijboer, Harry R. Buller, Anthonie Lensing, Alexander Turpie, Louisa P. Colly, and Jan Wouter ten Cate. A Comparison of Real-Time Compression Ultrasonography with Impedance Plethysmography for the Diagnosis of Deep-Vein Thrombosis in Symptomatic Outpatients NEJM Volume 329:1365-1369November 4, 1993Number 19.

  28. Venography • “?Gold Standard?” • Invasive • Contrast • Need experienced readers • Non-diagnostic up to 25%

  29. Upper Extremity DVT • 8% of all DVT • 75% are related to hypercoag, CVC • 25% Paget-von Schroetter syndrome • Exertional DVT • Caused by underlying MSK deformities (Thoracic outlet, extra rib)

  30. Upper Extremity DVT • Prandoni P, Polistena P, Bernardi E, Cogo A, Casara D, Verlato F, Angelini F, Simioni P, Signorini GP, Benedetti L, Girolami A. Upper-extremity deep vein thrombosis. Risk factors, diagnosis, and complications. Arch Intern Med. 1998 Sep 28;158(17):1950-2.

  31. Upper Extremity DVT • N=58 Sx UEDVT • IPG, Doppler, venography • 27 (47%) + UEDVT • Test Sens & Spec: • compression ultrasonography (96% and 93.5%) • color flow Doppler imaging (100% and 93%)

  32. Upper Extremity DVT • PE “Objectively” found in 36% • 2 yr F/U: 2 recurrent VTE • RF: • CVC • Thrombophilia • Previous VTE

  33. U/S Upper Extremity DVT • The sensitivity of duplex ultrasonography ranged from 56% to 100%, and the specificity ranged from 94% to 100% • Unsure if Helpful • Bisher O. Mustafa, MD; Suman W. Rathbun, MD; Thomas L. Whitsett, MD; Gary E. Raskob, PhD Sensitivity and Specificity of Ultrasonography in the Diagnosis of Upper Extremity Deep Vein Thrombosis: A Systematic Review Arch Int Med Vol. 162 No. 4, February 25, 2002.

  34. Upper Extremity DVT • 10-30% incidence PE associated • Therapy: • Usual Rx • Local thrombolytics appears to be Rx of choice with literature mainly case studies

  35. Treatment of VTE:Goals • reduce mortality • prevent extension/recurrence • restore pulmonary vascular resistance • prevent pulmonary hypertension

  36. Treatment of VTE:Anticoagulation • Out-patient LMWH • LMWH superior to UFH? (Gould 1999) • out-pt Rx safe in PE (Kovacs, 2000) • DVT: start Rx, definitive test in 24hr • baseline B/W

  37. Anticoagulation • Enoxaparin 1mg/kg bid or 1.5 od • Tinzaparin 175 anti-Xa u/kg od • start warfarin 5mg on day 1 • d/c LMWH when INR >2.0 x 2 days • Rx 3 mos if 1st and reversible cause • 6 mos if non-reversible • indefinite if recurrent, CA, genetic • Anticoagulation Clinic

  38. LMWH vs. UFH • N=432 • No difference in new VTE • Less died, complications in LMWH (SS) • RD Hull, GE Raskob, GF Pineo, D Green, AA Trowbridge, CG Elliott, RG Lerner, J Hall, T Sparling, HR Brettell, and et al Subcutaneous low-molecular-weight heparin compared with continuous intravenous heparin in the treatment of proximal-vein thrombosis NEJM Volume 326:975-982April 9, 1992Number 15

  39. Pregnancy • V/Q safe, no breastfeed x 15hr post • D-dimer  in pregnancy, wide Aa • angiography safer than empiric Rx • LMWH in DVT, not studied in PE • PE: UFH IV x 4-5 days, then s/c • treat x 3 months or 6 weeks postpartum • switch to oral postpartum

  40. PE: Early Rappers OR Badness in the Veins?

  41. PE Objectives • Epidemiology & Natural History • Mortality & Pathophysiology • Hx & PHx • Pre-test Probability • Dx • Angio, Echo, CT, algorithms • Which tests / combo rules in / out • What to do if non-Dx results • Confounding Clinical Situations • Rx • Heparin, Thrombolysis (massive, submassive), embolectomy, IVC filter

  42. Epidemiology • USA: 60-80% patients with DVT, >50% Sx free • 3rd in hospital mortality, 650,000 cases/yr • Autopsy studies: 60% pts who die in hospital had PE, diagnosis missed ~ 70%

  43. Natural History • Most pulmonary emboli are multiple, and the lower lobes are involved • From deep veins of lower extremities • Also pelvic, renal, upper extremity, right heart chambers • Large thrombi lodge @ bifurcation of main PA or lobar branches -> hemodynamic compromise • Smaller thrombi occlude smaller vessels in periphery • More likely to cause pleuritic chest pain (inflammatory response adjacent to parietal pleura)

  44. Mortality • Approximately 10% of patients who develop PE die within the first hour, • 30% die from recurrent embolism. Anticoagulant Rx decreases mortality < 5%

  45. Pathophysiology Review • Normal RV has a narrow range over which it can compensate for acute increases in afterload. The pericardium has a limited ability to distend. • Increased RV afterload elevation in RV wall pressures dilation and hypokinesis of the RV wall shift of intraventricular septum towards left ventricle (tricuspid regurgitation) and decreased LV output.

  46. Respiratory Consequences • Early • Increased alveolar dead space, Pneumoconstriction, hypoxemia, hyperventilation • Late: • regional loss surfactant, pulmonary infarction • Arterial hypoxemia frequent, not universal • V/Q mismatch, shunts, reduced CO, intracardiac shunt via PFO • Infarction uncommon re bronchial arterial collateral circulation

  47. Hemodynamic Consequences • Reduces X-sectional area of pulmonary vascular bed -> incr pulmonary vascular resistance -> RV afterload -> RV failure • Reflex PA constriction • Prior poor cardiopulmonary status important factor re hemodynamic collapse

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