Pulmonary embolism 2

PULMONARY EMBOLISM

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Wellcome in our new group ..... Dr.SAMIR EL ANSARY

Incidence

• The true incidence of PE is unknown and is suspected to be underestimated

• It is estimated to be between 0.5% to 3% in the general population

• Mortality from PE is estimated to be 0.1%

Risk Factors

• Previous or current DVT

• Immobilization

• Surgery within the last 3 months

• Stroke/paralysis

• Central venous instrumentation within the last 3 months

• Malignancy

• CHF

Risk Factors

• Autoimmune diseases

• Air travel

• Thrombophillias

• In Women

– Obesity (BMI ≥29)

– Pregnancy

– Heavy cigarette smoking (>25 cigarettes per day)

– Hypertension

Presentation

Dyspnea at rest or with exertion (73 %)

Pleuritic pain (44 %)

Cough (34 %)

>2-pillow orthopnea (28 %)

Calf or thigh pain (44 %)

Calf or thigh swelling (41 %),

Wheezing (21 %)

Rapid onset of dyspnea within seconds (46 %)

within minutes (26 %)

• Tachypnea (54 %)

• Tachycardia (24 %)

• Rales (18 %),

• Decreased breath sounds (17 %),

• Accentuated pulmoniccomponent of the second heart sound (15 %)

• Jugular venous distension (14 %)

Most Common SymptomsMost Common Signs

Clinical Decision Rules

Models for assessing clinical Probability of Pulmonary Embolism

Well’s Criteria

Geneva Score

Wells’ Score

Clinical symptoms of DVT (leg swelling, pain with palpation)

3.0

Other diagnosis less likely than pulmonary embolism

3.0

Heart rate >100 1.5

Immobilization (≥3 days) or surgery in the previous four weeks

1.5

Previous DVT/PE 1.5

Hemoptysis 1.0

Malignancy 1.0

Traditional clinical probability assessment (Wells criteria)

High >6.0

Moderate 2.0 to 6.0

Low <2.0

Simplified clinical probability assessment (Modified Wells criteria)

PE likely >4.0

PE unlikely ≤4.0

Simplified Geneva Score

Variable Score

Age >65 1

Previous DVT or PE 1

Surgery or fracture within 1 month 1

Active malignancy 1

Unilateral lower limb pain 1

Hemoptysis 1

Pain on deep vein palpation of lower limb and unilateral edema

1

Heart rate 75 to 94 bpm 1

Heart rate greater than 94 bpm +1

Score of less than 2 is low probablility for PE, score of less than 2 plus a negative D-dimer results in a likelihood of PE of 3%

Diagnostic tests

D-Dimer

Elevated in thrombosis, malignancy, pregnancy, elderly, hospitalized patients

Role in low or moderate probability for PE

Normal results can rule out PE

Estimated 3 month risk of thromboembolism with negative D-dimer is 0.14%

Role in high probability patients proceed to CT,

Negative d-dimer can miss up to 15% of patients in this group

EKG in Pulmonary Embolism

Most commonly sinus tachycardia, with possible nonspecific ST/T wave changes

Only 10% of patients can have the S1Q3T3 so not reliable

Other EKG abnormalities including atrial arrhythmias, right bundle branch block, inferior Q-waves, and precordial T-wave inversion and ST-segment changes, are associated with a poor prognosis. S1Q3T3

Chest Radiography

• Not a sensitive or specific test for the diagnosis of PE.

• Atelectasis, Pleural effusion, or a pulmonary parenchymal abnormality is noted most commonly

• Only a small portion of patients with PE have a normal CXR.

The sign results from a combination of:•dilation of the pulmonary arteries proximal to the embolus•collapse of the distal vasculature creating the appearance of a sharp cut off on chest radiography•The Westermark sign has a low sensitivity (11%) and high specificity (92%) for the diagnosis of pulmonary embolus

Radiographic Signs Westermark Sign

Radiographic Signs – Hamptons HumpWedge-shaped infarctsensitivity (21) and specificity (82%) for the diagnosis of pulmonary embolus

Ventilation-Perfusion Scans Useful if Normal (negative predictive value of 97%)

Also useful if High probability (positive predictive value of 85 to 90%)

Unfortunately, only diagnostic in 30 to 50% of patients

CT Angiography

CT Angiography

Studies have shown sensitivity of close to 95% with an experienced observer

One of the most commonly cited benefits of CTA is its ability to detect alternative pulmonary abnormalities that may explain the patient's symptoms and signs

In 67% of patients without PE, CT provided additional information for alternate diagnosis

May predispose patients to further unnecessary testing

CT A

giogram

Acute pulmonary embolism and deep venous thrombosis (DVT) in a 48-year-old woman. Multifocal low-attenuation emboli (arrows) in segmental and subsegmental arteries in the right lower lobe.

Pulmonary Angiography

Pulmonary Angiography in PE

The “gold standard”A negative pulmonary angiogram excludes clinically

relevant PE.

The risk of embolization in patients with a negative angiogram is extremely low

Diagnostic Pathways

Is it important to useclinical decision rules?

• In the setting of no thromboembolic risk factors, it is extraordinarily unlikely (0.95% chance) to have a CT angiogram positive for PE.

• With the combination of a negative D-dimer test result, this risk is even lower.

Diagnostic Algorithm

When PE is suspected, the modified Wells criteria should be applied to determine if PE is unlikely (score ≤4) or likely (score >4). The modified Wells Criteria include the following:

Patients classified as PE unlikely should undergo D-dimertesting with a quantitative rapid ELISA assay or a semiquantitative latex agglutination assay.

The diagnosis of PE can be excluded if the D-dimer level is <500 ng/mL or negative.

Patients classified as PE likely and patients classified as PE unlikely who have a D-dimer level >500 ng/mL should undergo CT-PA. A positive CT-PA confirms the diagnosis of PE. Alternatively, a negative CT-PA excludes the diagnosis of PE.

In those rare instances in which the CT-PA is inconclusive, either pulmonary angiography or the diagnostic approach intended for institutions without experience in CT-PA can be used.

Lower Extremity US indicated?

Depends on pre-test probability

High pretest probablity for PE and negative CT may require additional testing

Good initial test to evaluate for pulmonary embolism in patients with contrast allergy, renal insufficiency, pregnancy, or critically ill patients.

Inexpensive test without radiation exposure

Can avoid additional testing if positive

Summary and Recommendations

Consider your patient’s risk factors for pulmonary embolism

The clinical presentation of acute pulmonary embolism is variable and nonspecific

The major diagnostic tests employed in the evaluation of a

patient with suspected PE include d-dimer testing, CTPA, V/Q scanning, venous ultrasonography, and conventional pulmonary angiography

Follow a diagnostic algorithm that combines CTPA, d-dimer and clinical assessment

https://www.facebook.com/groups/1451610115129555/#!/groups/1451610115129555/

Wellcome in our new group ..... Dr.SAMIR EL ANSARY

GOOD LUCK

SAMIR EL ANSARY

ICU PROFESSOR

AIN SHAMS

CAIRO

elansarysamir@yahoo.com