pulmonary thromboembolism

Pulmonary Thromboembolism

Prevention, Diagnosis, ManagementAlex 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 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: immobilityPost operative immobility

– Hip Fracture, or hip replacement– Knee replacement– Major Trauma– Spinal cord injury– Major general surgery eg. laparotomy – arthroscopic surgery

Immobility due to pathology– Paralytic stroke

Immobility due to circumstance– Bed rest > 3 days– Sitting immobility (air travel, movie marathon)– Obesity

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

OR > 10

OR 2-9

OR 1-2

Risk factors: Hypercoagulability

Hormone replacement therapy

Oral contraceptive therapy

Chemotherapy

Malignancy

Pregnancy: postpartum

Inherited thrombophilia

Pregnancy: antepartum

Increasing age (>40)Though risk increases for every decade over 40



OR 2-9

OR 1-2

Risk factors: Vessel wall abnormality

Central venous lines

Previous DVT / VTE

Varicose veins



OR 2-9

OR 1-2

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.

http://www.jccjournal.org/issues?Vol=20

http://www.jccjournal.org/issues/contents?issue_key=S0883-9441(05)X0064-8

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 edGeerts 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)


Signs

….Frequently, no signs!• Tachypnea (most common)• Tachycardia• Fever• Signs of right ventricular dysfunction

HUGE PE:- Hypotension- Cyanosis- Mottled skin


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


Specific investigations



- CTPA:- For large PE, very accurate; less so for small PE- Added bonus: compares RV:LV size ratio



- Ventilation-perfusion (V/Q ) scanning- Low probability does not satisfactorily exclude PE


Specific investigations- ECHO

- RV wall hypomotility, RV + RA dilatation- Sometimes, you can visualize the thrombus


Investigation Algorithm


Stable patient Unstable patient

Investigation Algorithm



CTPA or V/Q scan Transthoracic Echo

Severity Stratification




Little segmental

defects

Large defects, dilated RV,

visible PA clotRV dysfunction

Visible RV or PA thrombus

Management according to severity




Little segmental

defects

Large defects, dilated RV,

visible PA clotRV dysfunction

Visible RV or PA thrombus

Anticoagulate..or IVC filter

Anticoagulate if there is no RV failure, Thrombolyse if RV is dysfunctional

ThrombolysisEmbolectomy

Anticoagulation

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

ANTICOAGULATION: with what?

- HEPARIN: clexane as effective and safe as unfractionated

- UNFRACTIONATED for post-embolectomy or post-thrombolysis, 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 edSegal 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 edKucher 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 edKonstantinides et.al, Association between thrombolytic treatment and the prognosis of hemodynamically stable patients with major pulmonary embolism Circulation 1997; 96: 882-8Wan 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:- Thrombolysis is contraindicated, or has failed- Free-floating cardiac thrombus- Massive PE with shock


Friedrich Trendelenburg

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


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 edCapellier G,Jacques T, Balvay P, et al: Inhaled nitric oxide in patients with pulmonary embolism. Intensive Care Med 1997;23:1089-1092Webb 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 meta-

analysis 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.

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