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Venous Thromboembolism

Venous Thromboembolism. Denise Watt January 3, 2002. Outline. epidemiology pathophysiology risk factors diagnosis clinical labs diagnostic imaging algorithms treatment. Case 1. Rural ED 72 yo male fever, SOB, pleuritic CP x 2 days HR 110, bp 140/90, RR 22, sat 90%

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Venous Thromboembolism

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  1. Venous Thromboembolism Denise Watt January 3, 2002

  2. Outline • epidemiology • pathophysiology • risk factors • diagnosis • clinical • labs • diagnostic imaging • algorithms • treatment

  3. Case 1 • Rural ED • 72 yo male • fever, SOB, pleuritic CP x 2 days • HR 110, bp 140/90, RR 22, sat 90% • CXR unremarkable • what test/Rx?

  4. Case 2 • 55 yo man • sudden central CP, SOB, presyncope • HR 120, bp 90/70, RR 30, sats 88% • ECG: sinus tach • what tests/Rx?

  5. Case 3 • 33 yo healthy woman, 34 wks GA • syncope at home • EMS called • asystolic arrest en route • CPR x 5 min • what do you do?

  6. Epidemiology • Lifetime incidence VTE 2-5% • PE: 0.5/1,000/year • DVT: 1/1,100/year • PE mortality: • 10% die in 1st hour • 30% untreated • 2-8% if anticoagulated • >50% PEs undiagnosed

  7. Primary Factor V leiden Antithrombin III deficiency Prot C deficiency Prot S deficiency hyperhomo-cysteinemia anticardiolipin Ab dysfibrinogenemia Secondary age trauma / surgery malignancy immobilization stroke smoking obesity OCP/HRT lupus anticoagulant pregnancy hyperviscosity heart failure Risk Factors

  8. 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

  9. 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

  10. Hemodynamic tachycardia hypotension RV overload and dilation  CVP  LV preload  myocardial flow pulmonary HTN pul A-V shunts Respiratory hyperventilation PA HTN  compliance atelectasis broncho-constriction  airway resistance Consequences of PE

  11. Clinical Presentation:DVT • Calf-popliteal • 80-90%, many asymptomatic • pain & swelling • spreads proximally • Ileofemoral • pain in buttock, groin • thigh swelling • 10-20% cases

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

  13. Clinical Model for DVT

  14. Incidence of DVT by Clinical Probability

  15. Clinical Presentation of PE:The great pretender • SOB, CP or tachypnea in 97% • individual s+s not sensitive/specific • peripheral (distal vessel) • pleuritic CP, ± hemoptysis, ± SOBOE • central (lobar / segmental) • SOBOE • massive (main pulmonary artery) • syncope, hypotension, shock

  16. Clinical Prediction Model for PEWells. Ann Int Med, 1998

  17. Incidence of PE by Clinical Probability

  18. Ancillary tests for PE • CXR: • r/o other diagnoses • ‘classic’ signs non-specific • ABG: • 20% have normal PaO2 • 15-20% have normal Aa gradient • ECG: • remember???

  19. D-dimer • degradation product of fibrin • PPV poor; NPV excellent • non-specific: • +ve: surgery, trauma, hemorrhage, CA • 90% +ve >80 yrs old • most useful in ED patients • NOT to r/o PE in high PTP

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

  21. 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

  22. 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

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

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

  25. Diagnostic Imaging for PE:V/Q scan • PIOPED: ventilation component adds little info • PISAPED criteria: • normal, non-diagnostic, high probability • 25%, 50%, 25% respectively • high prob: 85-90% PPV • non-diagnostic: 25% PE • interpret in context of PTP

  26. Diagnostic Imaging for PE:Pulmonary Angiography • Gold standard (imperfect) • sens 98%, spec 95-98% • ED physicians reluctant to use: • invasive, risks, requires expertise, not readily available, time consuming, $ • relative contraindications • indicated if non-invasive tests inconclusive

  27. Diagnostic Imaging for PE:Spiral CT • IV contrast, direct visualization • subsegmental PE not well seen • more specific, underlying lung dx • sens depends on CT, experience • wide variation in studies • Rathbun. Ann Intern Med, 2000 (review) • sens 53-100%, spec 81-100% • poor methodolgy of studies

  28. Spiral CT • Perrier. Ann Intern Med, 2001 • sens 70%, spec 91% , 4% inconclusive • good interobserver agreement • CT venography: • benefit over U/S not determined • role? • no evidence to withold Rx if CT negative • may replace angiography

  29. Diagnostic Imaging in PE:Echocardiography • useful for patients in shock/arrest • r/o DDx: tamponade, Ao dissection, AMI • indirect evidence of PE: • RV overload, septal shift to L, TR,  PA pressure, RV wall motion abn • sens 93%, spec 81% • ‘sub-massive’ PE: independent predictor of mortality (?significance)

  30. Algorithm for suspected PE:Wells. Ann Int Med, 2001

  31. Wells’ Algorithm:Criticism • Uses SimpliRED assay: lower sens. • sCT not included • could replace angiography? • Low prevalence of PE (9%) • not validated by other RCTs

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

  33. 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

  34. 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-reversbile • indefinite if recurrent, CA, genetic

  35. Treatment of PE:Criteria for admission • Hemodynamic instability • O2 requirement • surgery < 48hr • risk of active bleeding • history of HIT • IV pain control

  36. Treatment of massive PE • judicious fluids (500cc max) • NE, dopamine, dobutamine prn • O2, intubate if shock • positive pressure worsens RV fn • anticoagulation • if no contraindications • UFH if hypotensive • PTT 1.5-2.5 x normal

  37. Treatment of massive PE:Thrombolytics • no evidence of mortality benefit • including in cardiac arrest (case series) • no benefit in hemodynamically stable • improves pul. perfusion (15% vs 2%), RV function (34% vs. 17%) cf. heparin • t-PA faster hemodynamic effect • IV same as intrapulmonary • 5-10% major bleed, 1-2% ICH

  38. Thrombolytics • 2 week window of opportunity! • effect  with time • no advantage of t-PA bolus • protocols: • t-PA: 100mg over 2 hr • UK: 4400U/kg over 10min; rpt x 12-24hr • SK: 250,000U over 30min; 100,000 x 24h • arrest: t-PA 10mg/kg bolus x 2 q 30 min

  39. Embolectomy • Indicated in acute, massive PE if: • contraindication to thrombolytics • unresponsive to medical mgt • moribund pt  poor results • no evidence cf. with thrombolytics • percutaneous vs. surgical • ?role

  40. IVC Filters • Indications: • contraindication to anticoagulation • recurrent VTE despite anticoagulation • after surgical embolectomy • no long term adv vs. anticoagulation • anticoagulate if no contraindications • DVT and IVC occlusion

  41. 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

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