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Pulmonary Embolism Diagnosis, Treatment, and Prevention

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Thrombosis that originates in the venous system and embolizes to the pulmonary ... (ie, active GI bleed, intracranial neoplasm, know bleeding diathesis), if ... – PowerPoint PPT presentation

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Title: Pulmonary Embolism Diagnosis, Treatment, and Prevention


1
Pulmonary EmbolismDiagnosis, Treatment, and
Prevention
  • Philip Keith
  • March 26, 2008

2
Pulmonary Embolism
  • Thrombosis that originates in the venous system
    and embolizes to the pulmonary arterial
    circulation
  • DVT in veins of leg above the knee (gt90)
  • DVT elsewhere (pelvic, arm, calf veins, etc.)
  • Cardiac thrombi

3
How Common?
  • 650,000 cases in the US each year
  • 150,000 200,000 US deaths each year
  • Most common preventable cause of hospital death
  • 3rd most common acute cardiovascular emergency
    (MI and stroke)

4
Risk Factors (for DVT)
  • Virchows Triad
  • Alterations in blood flow (stasis) best rest,
    inactivity/immobilization, CHF, paralysis
  • Injury to endothelium trauma, surgery
  • Thrombophilia Factor V Leiden, Protein C or S
    deficiency, etc.
  • Age gt50
  • History of varicose veins
  • History of MI
  • History of malignancy
  • History of atrial fibrillation
  • History of ischemic stroke
  • History of diabetes mellitus
  • Previous VTE, obesity, pregnancy

5
Clinical Presentation
  • Asymptomatic
  • Sudden onset of unexplained dyspnea
  • Pleuritic chest pain
  • Tachypnea
  • Tachycardia
  • Anxiety/agitation, cough, hemoptysis, syncope,
    fever, cyanosis, isolated crackles, pleural
    friction rub, loud P2, right-sided S3, pulmonary
    insufficiency murmur, elevated JVP, right
    ventricular heave, acute worsening of heart
    failure or lung disease

6
Broad Differential
  • Pneumothorax
  • Myocardial ischemia
  • Pericarditis
  • Asthma
  • Pneumonia
  • MI with cardiogenic shock
  • Cardiac tamponade
  • Aortic dissection
  • etc, etc, etc

7
Nonspecific Workup
  • Chest X-ray abnormal in 88 of acute PE
  • Atelectasis (60-70) most common finding in PE
    without infarction
  • Classic findings
  • Westermark sign (increased lucency in area of
    embolus)
  • Hampton Hump (wedge-shaped pleural-based
    infiltrate)
  • Abrupt cutoff of vessel
  • Pleural effusion
  • EKG
  • Most common sinus tachycardia /- nonspecific
    ST-segment and T-wave changes
  • Classic S1-Q3-T3 pattern
  • Other signs of right heart strain (ie, new RBBB
    and ST changes in V1,2
  • ABG
  • Normal does NOT rule out PE
  • Classic findings
  • Hypoxia, hypocapnia, respiratory alkalosis,
    increased A-a gradient

8
Westermark Sign
9
Hampton Hump
Occurs 12 to 36 hours after symptoms
begin usually indicates pulmonary infarction
10
EKG Findings
11
Evaluation and Diagnosis
  • Evaluation and imaging is dependent upon
    estimated pretest probability (Modified Wells
    Criteria)
  • Pretest probability
  • Low (lt2 points)
  • Intermediate (2-6 points)
  • High (gt6 points)

12
REFER TO ALGORITHM
13
D-dimer in evaluation of PE
  • High sensitivity but poor specificity
  • Negative ELISA has gt95 negative predictive value
    and can be used to r/o PE in low risk patients
    (less than 2 points)

14
Helical CT
  • Sensitivity 85 (more sensitive for proximal
    emboli)
  • Specificity 95
  • Values vary widely in literature

15
Bilateral PE
16
V/Q Scan
  • Identifies mismatches between areas that are
    ventilated but not perfused
  • Best initial test in patients with clear CXR
  • Scan can be interpreted as High, Intermediate, or
    Low probability of PE, or normal
  • Normal rules out PE
  • High-probability scan is diagnostic of PE if the
    clinical suspicion is also high
  • Low-probability scan rules out PE only in a pt
    with low pretest clinical probability (because PE
    is found in roughly 15 of pts with
    low-probability scans)
  • Intermediate-probability scan requires further
    evaluation (16-66 chance of PE depending on
    pretest probability)

17
V/Q Scan
18
Duplex US with compression of the lower
extremities
  • Non-invasive test that accurately detects
    proximal DVT in LE (70-80 of pts with PE have
    concomitant proximal DVT)
  • Often used in workup of PE before going to more
    invasive procedures
  • SEE ALGORITHM

19
Pulmonary Angiography
  • Gold Standard
  • Invasive study
  • 5 morbidity
  • lt 0.5 mortality
  • Indicated if the diagnosis remains uncertain
    after noninvasive testing

20
PE on pulmonary angiogram
21
Treatment of PE
  • Acute anticoagulation to therapeutic levels
  • IV UFH 80 U/kg bolus, then 18 U/kg/hr to goal
    PTT of 46-70 seconds OR
  • LMWH ie) lovenox 1 mg/kg SUBQ BID then start
    warfarin (when PTT is therapeutic on UFH or on
    day 1 of LMWH), overlap x 5 days, titrate to INR
    2.0 to 3.0
  • Thrombolysis for massive PE causing hemodynamic
    compromise
  • IVC Filter if anticoagulation is contraindicated
    (ie, active GI bleed, intracranial neoplasm, know
    bleeding diathesis), if thrombus formed despite
    adequate anticoagulation, or with a large burden
    of thrombosis in the LE that could be fatal if
    embolized

22
Treatment of PE
  • Long-term anticoagulation
  • 1st event with reversible RF 3-6 mo warfarin
  • Idiopathic PE/DVT gt or 6 mo warfarin
  • 2nd event, cancer, non-modifiable RF 12 mo to
    lifelong warfarin
  • LMWH has been shown to be superior to warfarin in
    long term treatment in pts with cancer

23
DVT/PE Prophylaxis
  • Moderate to High Risk Patients (gt2 RF)
  • Lovenox 30 mg SUBQ q 12 hours OR
  • Lovenox 40 mg SUBQ daily
  • SCD at all times except when ambulating
  • Low to Moderate Risk Patients ( 1 RF)
  • Lovenox 40 mg SUBQ daily OR
  • SCD at all times except when ambulating
  • No Risk Factors
  • Ambulate in hallways or room QID
  • TED hose or SCD
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