PULMONARY EMBOLISM
PRESENTATION TO DIAGNOSIS
Objectives
 Review
the incidence, symptoms and
presenting signs of PE
 Learn about clinical prediction models
 Learn about different diagnostic methods
and diagnostic algorithms.
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

Autoimmune diseases

Air travel *

Thrombophillias

In Women

Obesity (BMI ≥29)

Pregnancy

Heavy cigarette smoking (>25 cigarettes per day)

Hypertension
Presentation
Most Common Symptoms








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 %)
Most Common Signs

Tachypnea (54 %)

Tachycardia (24 %)

Rales (18 %),



Decreased breath sounds
(17 %),
Accentuated pulmonic
component of the second
heart sound (15 %)
Jugular venous distension
(14 %)
Case

A 63-year-old woman with stage IV lymphoma calls 911 for
acute shortness of breath (SOB). At baseline, the patient is
mobile and does not have SOB. She is also taking hormone
replacement therapy. On the day of admission, she develops
a sudden SOB and new pleuritic chest pain. She does not
improve with nebulizer treatment on the way to the hospital.
In the ER, her pulse is 115 bpm, RR = 36/min, temp = 100.1oF
and O2 sat = 88% on room air. On exam, her lungs are clear,
and her extremities are normal. A chest x-ray (CXR) shows mild
right-sided atelectasis. An ABG shows ph = 7.48, PCO2 = 32
mm Hg and PO2 = 50 mm Hg on room air.

What is this patient’s pretest probability for having a
pulmonary embolism?
What diagnostic method would you use to confirm this?

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.
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.
Radiographic Signs – Westermark Sign
Radiographic Signs – Hamptons Hump
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 Agiogram
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 use clinical 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 Ddimer test result, this risk is even lower.
Diagnostic Algorithm
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
Case Presentation

Reminder:
 A 63-year-old woman with stage IV lymphoma with
acute shortness of breath (SOB) and pleuritic chest
pain. At baseline, the patient is mobile and does not
have SOB. She is also taking hormone replacement
therapy. In the ER, her pulse is 115 bpm. On exam, her
lungs are clear, and her extremities are normal. A
chest x-ray (CXR) shows mild right-sided atelectasis.
An ABG shows ph = 7.48, PCO2 = 32 mm Hg and PO2
= 50 mm Hg on room air.
Case Presentation




Applying the Wells’ Scoring system, the patient
has a moderate likelihood of having a PE with
a score of 5.5 for high clinical suspicion for PE,
tachycardia, and cancer.
Considering the patient’s score is >4, may
proceed to CT angiography for PE rule out.
This patient did have CTA performed, which
confirmed presence of PE.
She was subsequently started on
anticoagulation
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