DVT and PE

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DVT and PE

• Pathophysiology, prophylaxis, treatmentAnton
  Sharapov

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Cases to consider

• 38 yom for elective IHR
• 65 yom for elective IHR
• 65 yom, obesity/CHF/prev DVT for IHR
• 25 yof post severe head injury
• 25 yom post trauma/abdo/chest
• 75 yof post hip
• 65 yom post THA, obese

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• Scope of the problem

• Common postop complication
• Asymptomatic gt symptomatic
• Difficult to study
• Most studies evaluate asymptomatic pts

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Epidemiology

• VTE 48100,000
• PE 69100,000
• Incidence 20-70 surgery pts
• ½ begin in OR

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Epidemiology

• DVT and PE different stages of same disease
  process
• 10 proximal DVTs progress to symptomatic PE
• 25 distal DVTs become proximal

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Outcomes

• Most asymptomatic VTE recover sans treatment and
  complications
• Less then 1 in 8 confirmed clots progress to
  symptomatic thromboembolic disease
• Important to observe clots over a period of time

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Outcomes of PE

• Outcomes of PE are difficult to assess
• Registry estimates are always higher then in
  clinical studies (7 vs 2)
• Mortality is a function of RV function, clot
  burden, and comorbidities
• Risk of fatal PE greatest 3-7 postop
• Asymptomatic PE are common
• 40 of asymptomatic prox DVTs

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Assessment

• Assess risk of DVT and risk of bleeding
• Assess duration of prophylaxis
• Assess Virchov triad
• Venous stasis
• Endothelial injury
• hypercoagulability

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Risk factors venous stasis

• Immobility tourniquet application
• Institutionalization
• CVA
• Paralysis
• CHF
• Travel gt4 hours
• Obesity
• Respiratory failure
• Varicose veins
• Duration/extent of postop immobilization

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Risk factors endothelial injury

• Trauma
• Atherosclerosis
• Perioperative
• Malignancy
• Post-phlebitic syndrome
• Prior DVT
• CV catheter
• Inflamatory condition
• Hyperhomocysteinemia

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Risk factors hypercoagulability, Acquired

• Post op
• Malignancy
• Hormone replacement
• Estrogen therapy

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Risk factors hypercoagulability, Acquired

• Antiphospholipid antibody
• Lupus anticoagulant 5-10 fold risk
• Myeloproliferative d/o
• Paroxysmal nocturnal hemoglobinuria
• Nephrotic syndrome
• Pn loosing enteropathy

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Risk factors hypercoagulability, Inherited

• Factor V leiden APC resistance
• Absolute risk post op VTE is small - 1/100
• Relative risk increased (3-5 fold)
• Screening not recommended
• Antithrombin, pn C/S deficiency
• Fibrinogen/TPA defects
• Prothrombin gene mutation

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Risk factors Miscelaneous

• Use/nonuse of thrombopophylactic measures
• Age - rises linearly after 40
• Ethnicity
• Asian/South Pacific - threefold lower
• African American - slightly higher
• Latin - slightly lower
• Site/extent traumatic injury
• Knee/spinemajor traumagthipgturo/gynygt
  neurogtgeneral/thoracic

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Risk of DVT, miscellaneous

• Surgical procedure - most important
• Neurosurgery ortho - 6 3
• Major vascular
• Bowel, bladder, gastric bypass and kidney
  transplant
• Radical neck, IHR, lap chole (0.3),TURP,
  thyroid/parathyroid - lowest risk

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Need for global integrative assessment

• American College of Chest Physicians
• Risk stratification tool
• Problems
• What defines major vs minor surgeries?
• No weighting of Risk Factors
• Why age 40 and 60 important?

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(No Transcript)
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Risk of bleeding

• Bleeding d/o
• Use of antiplatelet meds
• Previous GI bleed
• Cancer
• Hepatic/renal insufficiency
• ?age

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VTE prophylaxis whats available?

• Intermittent compression devise
• Stockings
• ASA 80-325 mg
• UF heparin 5000 bid, tid
• LMW bid
• Warfarin
• Anti Xa pentasaccharide (fondaparinix)

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Efficacy of mechanical VTE prophylaxis
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Early ambulation

• Routine for all pts
• Acceptable as sole mode for low risk
• Useful adjunct esp post knee/hip surgery

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Elastic stockings

• First shown to work in 1952
• Decrease venous pooling
• Evidence of benefit for mod/high risk, but used
  only as adjunct
• Harmful if not work correctly

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ICD

• Work very well
• Not useful form BMI gt25
• Only effective if used correctly and continuously
  when pt not ambulating
• Have potential to reduce ambulation
• Recommended in mod-high risk gyn surgery as solo
• Not recommended as sole mode in
• Highest risk except neurosurgery
• High risk urological
• Hip and knee surgery

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IVC

• For absolute contraindication of anticoagulation
• For life-threatening hem on AC
• For failure of AC
• Used to prevent fatal PE
• Temporary filters preferred
• If left in place, cause DVTs

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Efficacy of pharmacological VTE prophylaxis
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Aspirin

• Not recommended as sole prophylaxis
• Beneficial post hip-fracture
• 160 mg OD, 5/52, 13,000 pts
• Combined with routine prophylaxis
• PE 0.7 vs 1.2
• Fatal PE 18 vs 43

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UF heparin

• Good for moderate risk gen surgery
• Modest increase in bleeding
• Compared to LMWH (2.65 vs 1.8)
• Additive effect of stockings and ICD
• Risk of HIT

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warfarin

• For very high risk with lower extremity
  orthopedic and neuro surgery
• For gen surgery other methods work just as well
• Good for extended prophylaxis
• Delayed onset of action, may start preop!
• Recommended for
• Hip , THA, TKA

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LMW heparin and Pentasaccharideds

• Preferential inhibition of factor Xa
• FDA approved for DVT prophylaxis
• Not FDA approved as of yet for DVT prophylaxis in
  pregnancy, spinal cord injury, trauma,
  neurosurgery but are being used

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LMW heparin and Pentasaccharideds contd

• Effective for mod risk general surgery
• Gyn/obs
• second line to mechanical
• Trauma
• Method of choice only if risk of bleeding is not
  significant. If it is stocking/-ICD
• Recommended for ortho lower extremity surgery
• Fondoparinix reduces asymptomatic DVTs only

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LMW heparin and Pentasaccharideds contd

• Risk of epidural hematoma
• Strategies
• Avoid regional anesth in those prone to bleed
• Needle in 12 h after onset of LMWH
• Single dose anesthetic better then infusion
• D/c cath in 12 h
• No dosing of LMWH within 2 h of cath d/c

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Direct thrombin inhibitors

• Effective in initial studies
• Comparable to LMWH
• For HIT pts

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Duration of prophylaxis

• Start immediately after or prior to surgery
• 7-10 days post
• Warfarin may be started 10/7 prior but INR should
  be less then 1.5
• Argument for prolonged (30 day) prophylaxis for
  high risk. DVT incidence
• sympt 3 vs 1 on treatment
• Asympt 19 vs 9 on treatment

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Prolonged prophylaxis

• Orthopedics
• Post THA for 4-6 weeks with LMWH or warfarin,
  especially with Risk Factors
• Obesity, sedentary, prior DVT
• General surgery
• Prolonged treatement with LMWH prevents out-pt
  DVTs but at a marginal cost that was deemed
  inappropriate

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Screening for DVT?

• Not in the asymptomatic pts.

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Diagnostic strategy of DVT

• Suspect
• Dupplex
• For proximal or ANY symptomatic treat
• For distal AND asymptomatic follow with serial
  duplex US

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Accuracy of Tests for Diagnosis of PE

• Clinical suspicion is paramount

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Diagnostic strategy for PE

• Suspect
• VQ
• If normal AND D-Dimer low ruled out
• If high probability start treatment
• If indeterminate/nondiagnostic angio, angio CT

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Treatment

• IV heparin, aPTT 1.5- 2.3 normal 5/7
• May use LMW
• Coumadin INR 2-3
• Overlap heparin and warfarin 4/7
• On warfarin 3-6/12
• Consider ECHO/trop to evaluate RVF for PE to id
  High Risk pts.

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Treatment

• Hemodynamically unstable PE may require pressure
  support, fluid status monitoring, and/or
  thromolysis / surgery

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Cases to consider

• 38 yom for elective IHR
• None, low risk
• 65 yom for elective IHR
• Moderate risk, Consider UN heparin pre-op,
  ambulation, stockings post op
• 50 yom, obesity/CHF/prev DVT for IHR
• High risk, consider LMWH preop/post op. Conisder
  warfarin

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Cases concluded

• 25 yof post severe head injury
• High risk, mechanical,
• 25 yom post trauma/abdo/chest
• High risk, mechanical initially, consider LMWH
  when risk of bleeding is low
• 75 yof post hip
• High, consider LMWH periop, warfarin or aspirin
  post op
• 65 yom post THA, obese
• High, consider LMWH periop, warfarin or aspirin
  post op