Pulmonary Thromboembolism
Prevention, Diagnosis,
Management
Alex Yartsev (October 2010)
Embolism?
• Something obstructing the vessel
• Piece of fat
• Piece of tissue
• Bubble of gas
…CLOT
• Venous thromboembolism: DVT and PE
Aetiology: Where are these clots coming from?
•
•
•
•
•
Deep veins of lower limbs
Pelvic veins
Inferior vena cava
Occasionally, deep veins of upper limbs
Rarely, tips of central lines
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Aetiology: why are these clots forming?
• Virchow’s Triad
• Immobility
• Hypercoagulability
• Vessel wall injury
Virchow RLK (1856). "Thrombose und Embolie. Gefässentzündung und septische Infektion". Gesammelte
Abhandlungen zur wissenschaftlichen Medicin. Frankfurt am Main: Von Meidinger & Sohn. pp. 219–732.
Risk factors: immobility
Post operative immobility
–
–
–
–
–
–
Hip Fracture, or hip replacement
Knee replacement
Major Trauma
Spinal cord injury
Major general surgery eg. laparotomy
arthroscopic surgery
OR > 10
Immobility due to pathology
– Paralytic stroke
OR 2-9
Immobility due to circumstance
– Bed rest > 3 days
– Sitting immobility (air travel, movie marathon)
– Obesity
OR 1-2
Anderson F, Spencer F; Risk Factors for Venus Thromboembolism; Circulation 2003;107;I-9-I-16
*OR: Odds ratio, a measure of effect size; ratio of odds of one event to the odds of another event
Risk factors: Hypercoagulability
Hormone replacement therapy
Oral contraceptive therapy
Chemotherapy
Malignancy
Pregnancy: postpartum
Inherited thrombophilia
Pregnancy: antepartum
Increasing age (>40)
OR 2-9
OR 1-2
Though risk increases for every decade over 40
Anderson F, Spencer F; Risk Factors for Venus Thromboembolism; Circulation 2003;107;I-9-I-16
*OR: Odds ratio, a measure of effect size; ratio of odds of one event to the odds of another event
Risk factors: Vessel wall abnormality
Central venous lines
Previous DVT / VTE
Varicose veins
OR 2-9
OR 1-2
Anderson F, Spencer F; Risk Factors for Venus Thromboembolism; Circulation 2003;107;I-9-I-16
*OR: Odds ratio, a measure of effect size; ratio of odds of one event to the odds of another event
Epidemiology
• 1 in 1000 in general population
• Variable in critical care.
– From 0.4% to 8.3%, depending on who you talk to
• Up to 40% of pts with DVT will develop PE
• Up to 5% of pts with PE devlop pulmonary hypertension
Patel R., et al Burden of Illness in venous ThromboEmbolism in Critical care: a multicenter
observational study J Crit Care Volume 20, Issue 4, Pages 341-347
Muscedere J, et. al., Venous thromboembolism in critical illness in a community intensive care uni,
J Crit Care Volume 22 Issue 4 Pages 285-289
Rocha AT Tapson VF Venous thromboembolism in intensive care patients. Clin Chest Med. 2003
Mar;24(1):103-22.
Prophylaxis
- Everyone should get heparin or clexane
- Everyone should get TEDs or calf compressors
- Everyone should be mobilized early
- Aspirin can be used, but is less efficacious
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Geerts et. al. Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic
and Thrombolytic Therapy. Chest. 2004 Sep;126(3 Suppl):338S-400S.
Symptoms
•
•
•
•
Dyspnoea
Syncope
Pleuritic chest pain
Hemoptysis
– Most patients will have at least one
– Chest pain and hemoptysis is a late sign (pulmonary infarction)
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Signs
….Frequently, no signs!
• Tachypnea (most common)
• Tachycardia
• Fever
• Signs of right ventricular dysfunction
HUGE PE:
- Hypotension
- Cyanosis
- Mottled skin
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Xray Findings
• Focal oligaemia: reduced vascular markings
• Peripheral wedge-shaped density
• Enlarged left descending pulmonary artery
Or more likely, and less specific…
• Cardiac enlargement
• Elevated hemidiaphragm
• Atelectasis
ECG Findings
• Normal in 1/3rd
•
•
•
•
•
Sinus tachy
Non specific STD / TWI in anterior leads (right heart strain)
Right axis deviation
RBBB
Classic S1 Q3 T3 :
– Deep S wave in lead I
– Q wave and inverted T wave in lead III
Bloods
-
Troponin may be raised
A-a gap may be increased
CO2 may be low
Metabolic acidosis may be present
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Specific investigations
- D-Dimer:
-
Fibrin degradation product
Comes from any fibrin, anywhere
Normal = highly unlikely there is VTE
Abnormal = could mean anything
Elevated in MI, malignancy, trauma,
infection, DIC, heart failure
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Specific investigations
- CTPA:
- For large PE, very accurate; less so for small PE
- Added bonus: compares RV:LV size ratio
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Specific investigations
- Ventilation-perfusion (V/Q ) scanning
- Low probability does not satisfactorily exclude PE
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Specific investigations
- ECHO
- RV wall hypomotility, RV + RA dilatation
- Sometimes, you can visualize the thrombus
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Investigation Algorithm
Stable patient
Unstable patient
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Investigation Algorithm
Stable patient
CTPA or V/Q scan
Unstable patient
Transthoracic Echo
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Severity Stratification
Stable patient
CTPA or V/Q scan
Little
segmental
defects
Large defects,
dilated RV,
visible PA clot
Unstable patient
Transthoracic Echo
RV dysfunction
Visible RV or
PA thrombus
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Management according to severity
Stable patient
CTPA or V/Q scan
Little
segmental
defects
Anticoagulate
..or IVC filter
Large defects,
dilated RV,
visible PA clot
Unstable patient
Transthoracic Echo
RV dysfunction
Anticoagulate if there is no RV failure,
Thrombolyse if RV is dysfunctional
Visible RV or
PA thrombus
Thrombolysis
Embolectomy
Anticoagulation
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Management according to severity
-Small PE, no RV dysfunction:
- anticoagulation only
-Submassive PE, RV dysfunction but hemodynamically stable:
-Strongly consider thrombolysis
-Also anticoagulate
- MASSIVE PE:
- remove the thrombus somehow, either by
embolectomy or by thrombolysis
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
ANTICOAGULATION: with what?
- HEPARIN: clexane as effective and safe as unfractionated
- UNFRACTIONATED for post-embolectomy or postthrombolysis, as it can be reversed quickly with protamine
The key is to achieve therapeutic levels quickly: subtherapeutic levels
increase risk of recurrence
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Segal JB et al., Management of venous thromboembolism: a systematic review for a practice guideline
Ann Int Med 2007; 146: 211-222
Inferior Vena Cava Filter
- If anticoagulation is contraindicated
- If there have been RECURRENT PE
while the patient is already
anticoagulated
- Some newer ones are easily retrieved
- Improve 90 day mortality
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Kucher N. et al, Massive pulmonary embolism Circulation 2006; 1113: 577-82
Thrombolysis
- Hopefully, produces massive immediate improvement
in hemodynamic parameters
- The bigger the PE, the more useful the thrombolysis
- Randomized studies: no difference in mortality
- In submassive PE: reduce escalation of treatment
- In summary:
- Always useful in massive PE
- In submassive PE, useful if there is RV dysfunction
- Unlike MI, these are useful with 14 days of onset!
Complications: 10% will hemorrhage; 0.5% into the brain.
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Konstantinides et.al, Association between thrombolytic treatment and the prognosis of hemodynamically stable patients with major
pulmonary embolism Circulation 1997; 96: 882-8
Wan S et. al, Thrombolysis compared with heparin for the initial treatment of pulmonary embolism: a meta-analysis of randomized
controlled trials. Circulation 2004 110: 744-9
Embolectomy
- Perioperative mortality 25-50%
(as low as 7%-18% in some studies)
Percutaneous embolectomy: mortality still 20-30%
- Few studies comparing embolectomy and
thrombolysis
- Indications:
Friedrich Trendelenburg
- Thrombolysis is contraindicated, or has failed
- Free-floating cardiac thrombus
- Massive PE with shock
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Supportive measures
- GIVE THEM OXYGEN.
- Be cautious with fluids: too much will worsen RV function
- Elevate MAP while working to drop pulmonary
and right ventricular pressures
Use norad to increase coronary perfusion pressure
- ECMO/IABP
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Unusual measures
- Selective pulmonary vasodilators:
- Inhaled nitric oxide
- Inhaled prostacycline
- Limited supporting evidence, or animal studies
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Capellier G,Jacques T, Balvay P, et al: Inhaled nitric oxide in patients with pulmonary embolism. Intensive Care Med 1997;23:1089-1092
Webb SAR, Stott S, van Heerden PV: The use of inhaled aerosolized prostacyclin (IAP) in the treatment of pulmonary hypertension
secondary to pulmonary embolism. Intensive Care Med 1996 , 22:353-355
No questions, please.
References
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Bahloul M, Chaari A, Kallel H, Abid L, Hamida C, Dammak H, Rekik N, Mnif J, Chelly H, Bouaziz M.
Pulmonary embolism in intensive care unit: Predictive factors, clinical manifestations and
outcome. Ann Thorac Med 2010;5:97-103
Agnelli G,Becattini C, Acute Pulmonary Embolism N Engl J Med 2010;363:266-74.
Davies A, Pilcher D; Pulmonary Embolism (ch. 30) cit. Oh’s Intensive Care Manual 6th ed
Virchow RLK (1856). "Thrombose und Embolie. Gefässentzündung und septische Infektion".
Gesammelte Abhandlungen zur wissenschaftlichen Medicin. Frankfurt am Main: Von Meidinger & Sohn.
pp. 219–732.
Cohen AT, et al for the ENDORSE Investigators. Venous thromboembolism risk and prophylaxis in the acute hospital
care setting (ENDORSE study). Lancet 2008; 371: 387—94.
Heit et al; Risk Factors for Deep Vein Thrombosis and Pulmonary Embolism Arch Intern Med. 2000;160:809-815.
Anderson F, Spencer F; Risk Factors for Venus Thromboembolism; Circulation 2003;107;I-9-I-16
Patel R., et al Venous thromboembolism in critically ill patients: incidence and risk factors Critical Care 2007,
11(Suppl 2):P363
Muscedere J, et. al., Venous thromboembolism in critical illness in a community intensive care uni, J Crit Care
Volume 22 Issue 4 Pages 285-289
Segal JB et al., Management of venous thromboembolism: a systematic review for a practice guideline Ann Int Med
2007; 146: 211-222
Kucher N. et al, Massive pulmonary embolism Circulation 2006; 1113: 577-82
Konstantinides et.al, Association between thrombolytic treatment and the prognosis of hemodynamically stable
patients with major pulmonary embolism Circulation 1997; 96: 882-8
Wan S et. al, Thrombolysis compared with heparin for the initial treatment of pulmonary embolism: a metaanalysis of randomized controlled trials. Circulation 2004 110: 744-9
Geerts et. al. Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and
Thrombolytic Therapy. Chest. 2004 Sep;126(3 Suppl):338S-400S.