PE and DVT

1
PE and DVT
2
Pathogenesis of VT

• Virchows triad
• Damage to vessel wall
• Venous stasis
• Hypercoagulability

3
Source

• Most PEs originate from thrombi in the deep
  venous system of the legs, although they may also
  originate in the pelvic, renal or upper extremity
  veins.
• HOWEVER, less than 30 of pts will have symptoms
  in their legs at the time of diagnosis of PE
• 20 of calf vein thrombi propagate above the
  popliteal fossa.
• 20 of lower extremity venous emboli begin in the
  proximal veins without prior calf involvement.

4
Acquired Risk Factors

• Age
• Previous thrombosis
• Immobilization
• Major surgery especially Ortho
• Estrogen OCP, HRT, SERMs
• Antiphospholipid Ab syndrome
• Malignancy
• Nephrotic syndrome
• Inflammatory bowel disease
• Myeloproliferative d/o esp p. vera and ET
• PNH
• Long distance air travel
• HIT

5
Inherited Risk Factors

• Factor V Leiden mutation
• G20210A prothrombin gene mutation
• Antithrombin deficiency
• Protein C or S deficiency
• Dysfibrinogenemia
• Hyperhomocysteinemia

6
Presentation

• Dyspnea
• Pleuritic chest pain
• Cough /- hemoptysis
• On exam may have
• Tachypnea
• Tachycardia
• S4
• Loud P2
• May have fever rarely gt102
• In massive PE can have hypotension and shock
• Look at legs for swelling and Homans sign but
  only helpful if positive.

7
Homans Sign

• Passive dorsiflexion of the foot with the knee
  straight may give pain in the calf and back of
  the knee when there is a deep venous thrombosis.
• Some concern that vigorous dorsiflexion of the
  foot can expel clot from the veins and so this
  test may have its dangers.
• The sign is not specific for DVT

8
DDX swollen calf

• DVT
• Bakers Cyst
• Cellulitis
• Gout if really bad it can sometimes look like a
  cellulitis
• If bilateral think about CHF, Nephrotic syndrome,
  liver failure, venous insufficiency, pregnancy or
  pelvic mass, vasodilators esp nifedipine

9
ABG

• Usually shows hypoxia, hypocapnia, respiratory
  alkalosis
• A-a gradient
• Normal 7-14 depending on age
• Increases with age, FiO2 and supine posture
• Estimate of normal for age
• Age/4 4
• A-a gradient (FiO2 x713 pCO2/0.8) PaO2
• If A-a gradient normal, PaO2 lt80, Pa CO2 gt45 then
  hypoventilation accounts for hypoxia
• Increased A-a gradient occurs in V/Q mismatch,
  shunting and any kind of barrier to diffusion
  (e.g. pulmonary edema)
• BUT can be normal and still have PE!

10
Labs

• Troponin, LDH, AST and BNP may all be elevated
• Check baseline CBC, PT/PTT/INR, Cr
• D-dimer
• Normal D-dimer excludes PE, but positive D-Dimer
  is not helpful (as it can be positive in many
  conditions including sepsis, immobility, post Sx
  and CAP)

11
(No Transcript)
12
(No Transcript)
13
EKG

• May have non specific ST and T wave changes
• Typical SI, QIII, TIII - rare.
• Sinus tachycardia
• T wave inversions in right to mid chest leads
• Poor R wave progression (acute RV dilation)
• P pulmonale
• RV conduction delays
• Right axis shift

14
CXR

• May have area of atelectasis
• May have wedge shaped infarct peripherally
• Pleural effusion occurs in about 40

15
DVT D-Dimer

• Fibrin degradation product elevated in active
  thrombosis
• Negative test can help exclude VTE
• Preferred test
• Quantitative Rapid ELISA sensitivity 96/95 for
  DVT/PE
• Other methods include latex agglutination and RBC
  agglutination (SimpliRED)

Stein PD, Hull RD, Patel KC, et al. D-dimer for
the exclusion of acute venous thrombosis and
pulmonary embolism a systematic review. Ann Int
Med. 2004140(8)589-602
16
DVT D-Dimer

• In 283 patients with suspected DVT, low-moderate
  Wells DVT score and negative d-dimer only 1 (NPV
  99.6) had DVT over next 3 months

• Sensitive d-dimer testing can rule out DVT in
  low-moderate risk patients

Bates SM, Kearon C, Crowther M, et al. Ann Intern
Med. 2003138787-94
17
Doppler US of lower extremities

• If high clinical suspicion should be repeated
  7-10 days after initial scan as below knee DVT
  can propagate
• Also remember that some pt develop DVTs
  elsewhere so you may not find a DVT in their
  legs if the source was their arm!

18
PE Assigning Pretest Probability

• Single most important step in the diagnosis of
  pulmonary embolism
• May be done based on clinical judgment or aided
  by a clinical scoring system
• Modified Wells Criteria is the most widely used
  and studied
• Reliably stratifies patients by likelihood of PE
  to allow selection of safe (lt2 VTE risk if no
  anticoagulation) management strategy

19
DVT Wells Score
The following were assigned a point value of 1 if
present

• Cancer
• Paralysis or plaster immobilization
• Bedrest gt 3d or surgery in past 4 wks
• Localized tenderness

• Entire leg swollen
• Calf gt 3cm larger than unaffected leg
• Pitting edema greater than unaffected leg
• Collateral superficial veins

• Alternative diagnosis more likely than DVT - 2
  points
• Probability High ( 3), Moderate (1-2) or Low (0
  or less)
• DVT risk High 75, Moderate 17, Low 3

Wells PS, Andersen DR, Bormanis J et al. Lancet.
19973501795-8
20
PE Imaging Studies

• PIOPED study quantified the value of V/Q scans in
  diagnosing PE
• Normal/near-normal scans exclude PE in
  low-moderate risk patients
• High probability scans confirm PE in
  moderate-high risk patients
• Drawbacks more difficult test and 73 patients
  had indeterminate scans
• LE compression US showing DVT helps
  diagnostically, but a negative study insufficient
  to exclude VTE

PIOPED Study. JAMA. 1990263(20)2753-59
21
Clinical Models to Assess PE Risk

• PIOPED Criteria Correlates well with incidence
  of PE
• Based entirely of clinician impression, not
  clinical risk factors

PIOPED Investigators. JAMA 1990 263 2753-2759.
22
PE Helical CT (CTA)

• Eng performed a systematic review (SR) of all
  studies SRs on CTA prior to 2003
• Only 1/6 SRs and 3/8 primary studies found CTA
  gt90 sensitive for PE
• In a similar SR in 2005 Roy concluded
• Negative CTA could safely exclude PE in low risk
  patients
• Negative LE US plus negative CTA could exclude PE
  in moderate risk patients
• At the time of those SRs no studies of faster
  multidetector CTA (MDCT) were available

Eng J, Krishnan JA, Segal JB, et al. AJR
2004183(6)1819-27. Roy PM, Colombet I, Durieux
P, et al. BMJ 2005331(7511)259.
23
PE PIOPED II

• Published June 2006 in NEJM
• 1090 consecutive patients with suspected PE
• All given Modified Wells Score
• MDCT - mostly 4 slice
• Gold standard composite - V/Q, angiogram LE
  US
• Findings
• MDCT sens 83 spec 96 for PE
• Positive predictive value gt90 in moderate/high
  risk
• Negative predictive value 96 in low risk
  patients but only 89 in moderate risk patients
• Findings generally consistent with Roys SR

24
(No Transcript)
25
V/Q scanning

• Look for evidence of ventilation perfusion
  mismatch
• Can only really be done if pt has normal CXR
• Normal scan virtually excludes PE even if pretest
  clinical probability was felt to be high.
• If a patient with intermediate clinical
  probability of PE has an intermediate scan then
  need further testing

26

• A 60-year-old man with asthma is evaluated in the
  emergency department because of the acute onset
  of chest pain while lifting a heavy object. The
  pain is sharp and accentuated by deep breathing
  and by movement of the upper extremities. It is
  located over the left precordium.
• The physical examination and chest x-ray are
  normal. A ventilation-perfusion lung scan shows
  matched areas of perfusion and ventilation.
• Which one of the following is the correct
  interpretation of the ventilation-perfusion lung
  scan?
• ( A ) Normal( B ) Low probability( C )
  Indeterminate( D ) High probability

27

• Correct Answer A
• The lung scan is normal, with matched perfusion
  and ventilation. This lung scan rules out a
  pulmonary embolism, and another source for the
  chest pain should be sought. Often asthma does
  complicate the interpretation of the lung scan,
  but the problem relates to matched defects in
  which the airway obstruction decreases the
  ventilation to an area of the lung. The
  consequent hypoxia in that area leads to
  reduction in blood flow in the same area. These
  areas are rarely segmental.

28
Spiral CT/CT angiogram

• Used if CXR not normal
• Picks up large central emboli but is less
  sensitive for the smaller peripheral emboli.
• True pulmonary angiography rarely used now,
  though can do direct thrombolysis in massive PE.

29
(No Transcript)
30
Echo

• More than 80 of pts with PE will have
  abnormalities of RV size or function, or TR.
• McConnells sign regional wall motion
  abnormalities that spare the R ventricular apex
  are very suggestive of PE
• BUT echo is only really used for Dx of massive
  lifethreatening PEs when rapid diagnosis is
  needed to determine whether thrombolysis should
  be given.

31
Treatment

• Identify any contraindications to
  anticoagulations if yes then IVC filter
• Inquire about h/o HIT
• If yes, then use direct thrombin inhibitor
• Assess need for hospitalization
• Extensive iliofemoral DVT with circ compromise
• Increased risk of bleeding
• Limited cardioresp reserve
• Poor compliance
• CI to LMW heparin

32
Treatment

• Administer LMW heparin or unfractionated heparin
• Goal 1.5-2.5 x PTT in first 24 hours
• Check platelet count on day 3-5
• Treat at least five days and until patients INR
  is gt2 on coumadin for two consecutive days
• Start coumadin on day 1

33
Treatment Duration

• 3-6 months in most patients
• Indefinite treatment
• gt1 spontaneous event
• One spontaneous life threatening event
• Antiphospholipid syndrome
• Antithrombin deficiency
• gt1 genetic allelic abnormality
• Homozygote for Factor V Leiden or prothrombin
  gene mutation
• Heterozygote for both
• Protein C/S deficiency
• Continuing RF especially active advanced CA

34
Contraindications to Anticoagulation

• Absolute
• Active bleeding
• Severe bleeding diathesis
• Platelet count lt20
• Neurosurgery, ocular surgery or intracranial
  bleeding within the past 10 days

35
Contraindications to Anticoagulation

• Relative
• Mild/moderate bleeding diathesis or
  thrombocytopenia
• Brain mets
• Major abdominal surgery within 2 days
• GI or GU bleeding within 14 days
• Endocarditis
• Severe HTN (SBP gt200, DBP gt 120)

36
Inferior Vena Cava Filter

• Reduce risk of PE but carry increased risk of DVT
• Use in pts with DVT who cannot take
  anticoagulation e.g. due to bleeding risk
• Also used with or without anticoagulation in
  patients with high risk of death should further
  PE occur.

37
Hypercoagulation Workup

• Test all patients for unprovoked VT for
  antiphospholipid ab syndrome and
  hyperhomocysteinemia

38
Hypercoagulation Workup

• Test for Factor V Leiden, prothrombin gene
  mutation and deficiencies of antithrombin,
  protein C/S in the following patients
• Family h/o VT
• VT before the age of 50
• Recurrent VT
• Thrombosis in an unusual site (mesenteric, renal,
  cerebral, hepatic)
• Heparin resistance (antithrombin deficiency)
• Warfarin induced skin necrosis (protein C/S def)
• Neonatal purpura fulminans

39
Hypercoagulation Workup

• Wait to check for deficiency in antithrombin,
  protein C or S until 2 weeks after
  anticoagulation rx is completed

40
VTE Prevention Underutilized

• DVT-FREE prospective registry of 5,451 patients
  at 183 US hospitals
• Only 32 of medical patients with DVT received
  DVT prophylaxis

41
VTE Prophylaxis in Medical Patients

• Indications
• CHF or severe respiratory disease
• Bedrest with additional risk factor
• Cancer
• Prior VTE
• Most ICU patients
• Options
• Low dose unfractionated heparin or LMWH
• Sequential compression devices
• Graduated compression stockings

• Acute neurologic disease
• Inflammatory bowel disease