Pulmonary Thromboembolism | Jindal Chest Clinic

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Pulmonary Thromboembolism
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Pulmonary Thromboembolism

• Migration of a clot (or clots) from systemic
  veins (venous thrombosis) to the pulmonary
  vascular bed
• Incidence Approx. 500,000/year in USA (about
  10 of 5 million venous thrombosis episodes)
• Approx. 10 (i.e. 50,000) are fatal

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Characteristics of P.E.

• Source Deep veins of legs
• Pelvic veins (women)
• Upper extremity
• Type Bland
• Septic
• Nature Blood, Air
• Others Tissue, fibres, liquid droplets, fat,
  amniotic fluid, parasites

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Venous Thrombosis

• Virchows Triad
• Stasis
• Hypercoagulability
• Vessel wall injury

• Deposition of platelets, fibrin and red cells on
  venous valves/ sinuses

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Thromboembolic Risk Factors

• Hereditary Thrombophilias
• Protein C deficiency
• Protein S deficiency
• Antithrombin III deficiency
• Factor V Leiden mutation
• Prothrombin 20210 G/A variation
• Hyperhomocysteinaemia
• Dysfibrinogenaemia
• Familial plasminogen deficiency

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B. Acquired Predispositions

• Medical
• Prior VTE
• Advanced age
• Malignancy
• CHF, CCR
• Stroke, Neph. syn
• Oestrogen therapy
• Obesity, IBD
• Immobilization
• APLA syndrome
• Lupus anticoagulant
• Behcets syndrome

• Surgical
• Major abdominal or N.S. procedures under GA for
  gt30 minutes
• Hip, knee arthroplasty
• Knee arthroscopy
• Hip fracture
• Major trauma
• Spinal cord injury
• Open prostatectomy
• Pregnancy and post partum period

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Air Embolism

• Accidental introduction during
• I.V. injections
• Haemodialysis
• C.V.P. lines
• Artificial pneumothorax or pneumomediastinum

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Factors influencing effects

• 1. Emboli related
• Size of vessel
• Nature of emboli
• Extent of pulm vasc bed occlusion
• 2. Patient related Preexisting cardiopulm status
• 3. Secondary effects
• Hypoxaemia
• Release of neuro humoral mediators
• Reflex stimulation

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Physiological Effects

• 1. Respiratory
• Increased dead space
• Hyperventilation
• Bronchiolar narrowing
• 2. Circulatory
• Systemic hypotension
• Pulmonary hypertension
• Pulmonary infarction
• 3. V/Q imbalances
• Venous admixture

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Diagnosis of DVT

1. Clinical features
2. Contrast venography
3. Impedance plethysmography
4. Real time ultrasonography
5. M.R. venography
6. Radio labeled antibody imaging

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Diagnosis of PTE

1. Clinical S S
2. Lab. data TLC, S. enzymes, D-dimer
3. ECG, Echocardiography
4. Art. blood gases Dead space A-a DO2
5. Chest radiography
6. V/Q scanning (Nuclear)
7. CT, spiral CT, MRI, Angiography (conventional
   angiography)

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Signs and Symptoms (P.E.)
Massive () Submassive () No cardiac/pulm disease ()
Dyspnoea 85 82 73
Chest pain 64 85 66
Cough 53 52 37
Haemoptysis 23 40 13
Tachypnoea 95 87 70
Tachycardia (gt100/min) 48 38 30
Loud P2 58 45 23
Rales 57 60 51
Phlebitis 36 26 11
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Electrocardiography

• Sinus tachycardia
• T wave inversion in leads V1-4
• S1Q3T3 pattern
• New RBBB
• New onset atrial flutter

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Radiological signs of PE 

• Common
• Atelectasis
• Raised hemidiaphragm
• Focal infiltrate
• Small pleural effusion
• Rare
• Focal oligemia (Westermarks sign)

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CT Angiography

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D-Dimer Assay

• Follows fibrinolysis of clot may rise within 1
  hour of PTE, circulating half life about 4-6
  hours
• Method ELISA (takes 2-4 hours)
• Rapid methods Need standardization

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Radionucleide Scanning

• Simple and safe, if available
• Technetium99m labelled microspheres (3-4 mCi of
  Tc99m)
• Intravenous injection supine position
• Counting on gamma camera
• Different projections
• Matching with freshly obtained CXR ventilation
  scanning (if mismatched)

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Ventilation Perfusion Scan

1. More useful if read along with clinical
   probability of PTE
2. High probability scan highly predictive of PTE
3. Normal or near normal scan virtually rules out
   PTE
4. Low, indeterminate or intermediate probability
   scans (30 have PTE) need further tests

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Management

• Prophylaxis
• Anticoagulation
• Heparin, Warfarin, LMWH
• Others Hirudins, Synthetic thrombin inhibitors
• Thrombolysis
• Interventional radiological techniques Clot
  lysis, disruption, removal
• Surgical methods

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Thrombolytic agents

• Streptokinase
• Urokinase
• Recombinant tissue plasminogen activator (rtPA)

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Thrombolytic therapy -Contraindications

• Absolute - Hemorrhagic stroke or stroke at
  anytime
• - Ischemic stroke in preceding six months
• - Central nervous system damage or neoplasm
• - Recent major trauma/surgery/head injury
• - Gastrointestinal bleeding within the last
  month Known active bleeding
• Relative - Transient ischemic attack in
  preceding six months
• - Oral anticoagulant therapy
• - Pregnancy or within one week postpartum
• - Traumatic resuscitation
• - Refractory hypertension (systolic blood
  pressure gt 180 mmHg)
• -Advanced liver disease, Active peptic ulcer
• - Infective endocarditis

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Anti-coagulation

• Heparin Low mol wt heparin. Reduces progression
  of clot and risk of further embolization.
  Subcutaneous administration
• Given for 5 days.
• Oral agents Warfarin
• Fondapernux
• Other agents
• Monitor INR

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Recommendations for duration of anti-coagulation
Thromboembolism Duration
PE secondary to a transient (reversible) risk factor 3 months
Unprovoked PE At least 3 months
First episode of unprovoked PE and low risk of bleeding, and in whom stable Anticoagulation can be achieved   May be considered for long term anti-coagulation
Second episode of unprovoked PE Long term anti-coagulation
PE and cancer LMWH should be considered for the first 3 to 6 months. After this period, anti-coagulant therapy with VKA or LMWH should be continued indefinitely or until the cancer is cured.
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Prevention of VTE

• Risk identification
• Low dose unfractionated heparin
• (5000 U, 8 or 12 hrs)
• Low molecular weight heparin
• Pneumatic compressive devices
• Sodium warfarin

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