pulmonary embolism

1. Pulmonary Embolism
Jeff Curly Hurley MD
Martin Luther King Jr.
Hospital
Charles Drew University

2. Objectives
 Perspective
– Are pulmonary embolisms bad?
 Presentation
– “I think I’m having a PE”
 Diagnosis
– Anxiety
 Treatment
– Now and Later
 Questions
– Designed to wreak havoc

3. Perspective
 Leading cause of Morbidity and Mortality
 Estimated at 780,000 deaths per year
 Difficult diagnosis to make
– In patients suspected of having the disease,
approximate 10-20% are positive
– Approximate 66% of PE cases are missed.
– Conversely, 62% of patients on anticoagulation
therapy for suspected PE and subsequently
died, no PE was found on autopsy

4. DVT to PE
 Diagnosis of DVT
– 600,000 hospitalizations
– Diagnosis is underestimated
 Diagnosis of PE
– 400,000 missed each year
– Mortality if untreated is 20-30%
– Mortality if treated is 2-10%
– 100,000 potential lawsuits
– Cardiac arrest (PEA): TEE demonstrated 36%
prevalence rate for PE

5. Vichow’s Triad
 Hypercoagulability
 Endothelial damage
 Stasis

6. Thromboembolism Risk Factors
 Age > 40 (old age in Rosen’s)
 History of venous thromboembolism
 Surgery longer than 30 minutes
 Prolonged immobilization (airplanes—ASA)
 CHF
 Cancer
 Obesity
 Pregnancy or recent delivery
 Hormone replacement therapy
 Hypercoagulable states

7. Thromboembolism Risk Factors
 Hypercoagulable states
– Factor V Leiden (Most common)
– AT III deficiency
– Protein C deficiency
– Protein S deficiency
– Prothrombin G20210A mutation
– Anticardiolipin antibody syndrome
– Lupus anticoagulant

8. DVT
 Homans’ and pseudo-Homans’
– Pseudo-Homans’: tenderness when squeezing the
calf
– Homans’: Foot held in plantar flexation
– Repudiated by Homan himself
 Classic physical findings present
– Only 50% have DVT
 Plegmasia Dolens
– White, painful, edematous, cold, and pulseless
– Limb threat—call vascular—or amputation required
 Approx. 60-80% of femoral, and 30-45% of calf
DVT’s embolize
 Only half of patients with a proven PE have U/S
evidence of a DVT
– Negative ultrasound does not exclude PE
 DVT may mimic cellulitis
 Axillary/Subclavian veins highest risk

9. PE
 Massive PE is one of the most common
causes of unexpected death
 10% of patients in whom acute PE is
diagnosed die within the first 60 minutes
 Recurrent PE / development of pulmonary
hypertension / chronic cor pulmonale
– occurs in up to 70% of patients
– Has a high mortality and morbidity
 PE is especially likely to be missed in older
patients

10. Presentation
 Typical
– Pleuritic chest pain
– Dyspnea
– Hypoxia
 Non typical
– Apprehension
– Cough
– Hemoptysis
– Sweating
– Non-Pleuritic chest pain
– Syncope

11. Presentation
 Classical Triad
– Chest pain, Dyspnea, Hemoptysis < 20%
– Dyspnea, Tachypnea, or Chest Pain--97%
 Other Symptoms
– Dyspnea (73%)
– Tachypnea (70-92%)
– Pleuritic chest pain (66%)
– Tachycardia (44%)
– Rales (58%)
– Temperature > 100 (43%)
– Leg Pain (26%)
– Tenderness on chest wall palpation is common

12. Differential Diagnosis
 Pneumonia
– PE in Patients with pneumonia is virtually always missed
 Asthma
– Bronchospasm on PE responds to asthma meds
– 50% of patients that die from Asthma have a different
diagnosis on autopsy
 Pleuritis
– rarely the correct diagnosis
 ACS/MI
– High level of confusion between PE and MI in patients
with impending arrest
 Carcinoma

13. Pursuing the Diagnosis
 General Rule:
– Whenever the patient has risk factors and
symptoms suggesting PE, and no other
reasonable diagnosis
– Shortness of breath is the most common
complaint associated with unexpected death
after ED discharge
 Clinical Suspicion (PIOPED):
– Intermediate clinical suspicion 64%
– High suspicion: 68% correct
– Low Suspicion: 91% correct

14. Work-Up
 Clinical evaluation
 EKG
 CXR
 ABG
 D-Dimer
 V/Q scan
 CTPA

15. Initial Studies
 Chest x-ray to R/O:
– PTX, PNA, CHF, CM,
Dissection
 Findings suggestive of PE
– Focal
infiltrates/atelectasis
(68%)
– Elevated
hemidiaphragm (24-
50%)
– Pleural effusion (48%)
– Prominent Pulm.
Arteries
– Hampton’s hump (35%)
– Westermark’s sign (7%)
 ECG to R/O:
– ACS/Pericarditis/Strain-
-prognostic
 ECG
– S1Q3T3 (indication
of right heart strain—
20-50%)
– ST-segment changes
(8-69%)
– Non-specific ST-T wave
changes (49-77%)
– RBBB (6-67%)
– T-Wave inversions (23-
64%)
– Atrial arrhythmias (3-
66%)
– Normal (9-30%)

16. Hampton’s Hump

17. Westermark

18. S1Q3T3

19. ABG
 ABG has zero predictive value
 A-a Gradient is often increased secondary to other
pulmonary pathology
 Gradient is usually about 15 in most patients
 PE does not often produce abnormalities in gas
exchange
 Most patients have a PaO2 less than 80 (75%)
 PaO2 is very sensitive to minute ventilation
– 1-2 breaths/ minute may normalize the PaO2
 Pulse ox often normal (100% tends to exclude PE)
 PIOPED Data:
– Low Sensitivity
– 14-38% of patients with normal ABG had PE

20. Pre-Test
Probability
For DVT

21. Clinical Probability: Wells
 Wells Criteria
Variable Points
HR > 100 1.5
Hx of DVT/PE 1.5
Immobilization 1.5
Hemoptysis 1
Malignancy 1
Symptoms of
DVT
3
PE more likely 3
Pretest Probability
Low < 2
Moderate = 2 to 6
High > 6

22. D-Dimer
 34- D-Dimer assays with varying degrees
of sensitivity
– ELISA assays: highly sensitive (95-99%), expensive
 Original tests were slow to be of value
– Run in batches/Highly skilled lab/Impractical in the ER
 Now rapid ELISAs are available with similar
sensitivities
– Latex agglutination: 85%-98%
– Quantitative is gold standard D-Dimer Test: Considered
positive if greater tan 500 ng/ml
– A positive D-Dimer does not meet the requirements for
an intent to treat
 Lower sensitivity (latex and whole blood)
D-Dimer insufficient to r/o PE ALONE
– ACEP Recommendations: in conjunction with Well’s

23. D-Dimer
 NEJM: D- Dimer only used in
patients who are low risk for PE
 High D-Dimer is meaningless
– Not established a diagnosis
 Side Note: D-Dimer not
necessary/not helpful for DIC
diagnosis
– Platelet trend, FSP/FDP, Fibrinogen
level, PT/PTT

24. D-Dimer
 Half-life is 8 hours
 Patients with symptoms of PE greater than
8 days
 Patients may have normally elevated D-
Dimers
– Pregnant patients (75%)
– Cancer patients (50%)
– Postpartum 1 week
– Age greater than 80
 Other disease processes:
– Sepsis, hemorrhage, MI, stroke, collagen
vascular diseases, liver disease

25. Statistics
 Sensitivity: ill
– A/(A +B)
 Specificity: well
– D/(C + D)
 Positive
Predictive Value
– A/(A +C)
 Negative
Predictive Value
– D/(B + D)
Disease
Present
Disease
Absent
Test
Positive
A C
Test
Negativ
e
B D

26. V/Q scan
 PIOPED data show that the
specificity is poor
– Normal V/Q scans—did angiogram—9%
positive for PE
 High-probability scan sensitivity of
41% and specificity of 97%
 65% of V/Q scans are interpreted as
low and intermediate scans which
generally requires further
investigation

27. Spiral CT Scan
 Highly sensitivity: 98-99%
 Safe
 British Thoracic Society: recommendation
that CTPA is the initial lung imaging study
for suspected PE
 NEJM:
– Positive Helical CT: anticoagulation
– Negative Helical CT: possible F/U with
compression ultrasound then possible
anticoagulation

28. Special Populations
 Recurrent visits in Pts. with diagnosed PE
– INR: if therapeutic (INR 2-3), no imaging
– NEW symptoms suggestive of recurrent PE:
use the same imaging modality
 Massive Obesity
– Greater than 400 lbs
– CT, V/Q, Angiogram: not feasible
– Venous ultrasound
– D-Dimer: greater than 2000—treat (no
evidence backing this recommendation—
Tintinalli’s)

29. Special Populations
 Pregnancy
– Involve obstetrician and radiologist
– Half dose injection V/Q scan
– CT angiogram
– Quantitative D-Dimer should not exceed 1000
ng/mL
– Doppler ultrasound
 Hypercoagulability
– May require higher INRs to be therapeutic (
>3)
– May render heparin and LMWH ineffective

30. ACEP Recommendations
 Level B recommendation that a quantitative
D-dimer excludes PE or lower extremity DVT
in low pre-test probability patients (as
assessed either subjectively or by clinical
scores).
 Level B recommendation that a negative
whole blood D-dimer assay in a low pre-test
probability patient as assessed by the Wells
criteria excludes PE or lower extremity DVT
 There was insufficient evidence to make any
Level B recommendations in regard to
utilizing the whole blood qualitative D-dimer
assay without Well's clinical scoring system.

31. ACEP Recommendations
 "In patients with a low-to-moderate pretest
probability of PE, and a non-diagnostic V/Q scan,
use one of the following tests instead of pulmonary
arteriogram to exclude clinically significant PE:
1. A negative quantitative D-dimer assay
(turbidimetric or ELISA).
2. A negative whole blood cell qualitative D-dimer
assay in conjunction with a Wells [PE] score of four
or less.
3. A negative single bilateral venous ultrasonographic
scan for low-probability patients.
4. A negative serial bilateral venous ultrasonographic
scan for moderate probability patients."

32. ACEP Recommendations
 PE policy Level B recommendation states,
"Consider fibrinolytic therapy in
hemodynamically unstable patients with
confirmed PE." The Level C
recommendation states, "Consider
fibrinolytic therapy in hemodynamically
stable patients with confirmed PE and RV
dysfunction on echocardiography," and, in
unstable patients with high clinical index
of suspicion, especially if RV dysfunction
can be demonstrated on bedside
echocardiography.

33. Treatment
– Anticoagulation:
 Prevent recurrent thromboembolism (rate new PE is
23% in 24 hours versus 6% in treated patients—
therapeutic aPTT)
 Started if suspected (pretest probability > 50%)
confirmed PE
 Can always stop Heparin Drip
– Unfractionated Heparin:
 Dose 80 U/kg Bolus, 18 U/kg infusion.
– Rosen’s: 60% of patients not therapeutic with
this dosing in the first 24 hours—recommend
100-150 Unit/Kg dosing
 Usually 5,000-10,000 U bolus (Rosen’s—10K start)
 PTT 60-80
 Effective anticoagulation has been shown to reduce
the overall mortality rate from 30% to less than 10%
 Heparin should be started as soon as the diagnosis of
pulmonary thromboembolism is considered seriously
 15 mg of protamine sulfate reverses anticoagulant
effect

34. Treatment
 Low Molecular Weight Heparin:
– 612 Patients (308 Heparin, 304 LMWH)
– No difference in mortality, recurrence, bleeding (NEJM)
– More effective anticoagulation—Better Xa:IIa ratio
– Less side effects
– Dose is 1 mg/Kg Q12 or 1.5 mg/Kg Daily
– Max Dose is 250 mg/day
– “In May 1998, LMWH (Enoxaparin, Rhone-Poulenc Rorer,
Collegeville, PA) was deemed approvable by the Food
and Drug Administration for in- and outpatient
treatment of DVT and PE and extended use of LMWH for
outpatient treatment of DVT and PE.“
– 1mg Protamine sulfate reverses 1 mg Lovenox
 Warfarin
– Goal of INR 2-3
– INR greater than 2.5 according to Rosen’s

35. HAT
 Heparin-Associated Thrombocytopenia
occurs in 4% of patients
– 2/3 of these patients will not have a reaction
to LMWH
– If HAT occurs, heparin must be stopped
immediately
 Diagnosed by disseminated thrombosis acutely
 Or by a falling platelet count over time
– Drug of Choice if HAT occurs is lepirudin
 Hirudins are direct inhibitors of Thrombin
– Lepirudin also DOC for AT III deficiency

36. Coagulation Cascade

37. Treatment
 Supportive:
– IVF
– Oxygen
 Even when PaO2 is normal—may dilate pulm. vasculature
– Pain control
 Morphine: pulmonary vasodilator
 Shock:
– Fluid Boluses
– Volume expansion may not beneficial: actually will
increase RV afterload and worsen RV function
– Shock should be treated with norepinephrine (Rosen’s)
– Fibrinolytics indicated: expected mortality decrease of
50%

38. Fibrinolysis
 Fibrinolytics/Surgery in cardiopulmonary arrest
– CPR has no benefit (36% of PEAs)
– Emergency cardiopulmonary bypass (one study that
showed 7 out of 9 patients survived)
– Bilateral emergency thoracotomy and massage of the
pulmonary vasculature
– Patient with known PE in ED or in transfer to the ED has
Arrest—give alteplase 100 mg bolus then CPR x 20
minutes
 Fibrinolytics indicated in:
– Cardiogenic shock
– RV Failure either by ECHO or strain on EKG
– Prior history of PE or known Protein C, Protein S, AT III
deficiencies (emedicine) (patients with high likelihood
for recurrences)

39. Fibrinolysis
 Indicated for iliofemoral DVT
– Call intervential radiologist
 Complications of fibrinolytics
– ICH bleeding 2%
– Bleeding 20%
 “Fibrinolysis should be considered for all patients
with PE who lack specific contraindications to the
therapy. Many centers now regard fibrinolysis as
the primary treatment of choice for all patients
with PE and even for all patients who have DVT
without evidence of PE” (emedicine)
 “Fibrinolysis is always indicated for
hemodynamically unstable patients with PE,
because no other medical therapy can improve
acute cor pulmonale quickly enough to save the
patient's life” (emedicine)

40. Fibrinolytics
 Reteplase: second generation
– FDA has not approved reteplase for use in PE
– Works faster
– More effective against larger clot burden
– Allows more clot dissolution
– 10 unit IVP Q30min X2
– Arrest: single 20 unit IVP
 Alteplase: Drug most commonly used in the ED
– Approved by FDA for use in PE
– 100 mg IV infusion over 2 h
– Accelerated 90-min regimen, most authors believe it is
both safer and more effective than 2-h infusion
(emedicine)
 Weight based
– Turn off heparin during infusion
– Aspirin Contraindicated

41. Bleeding Complications
 Reversal with FFP
– Usually 2 units
 Reversal with epsilon-aminocaproic
acid
– Amicar: 4-5 gms PO/IV over 1 hour
then 1 gm/hour as needed

42. Algorhythm

43. Consultations
 Decision to treat with thrombolytics
– Solely the responsibility of the ER doctor
 Interventional Radiology
– Catheter directed thrombolytics in selected
patients
– Placement of IVC filter
– Possible treatment of DVTs
 Rrosen’s: catherter-associated venous thrombosis
and for non-catheter related
– Decrease recurrence rate of DVT by 50%
– Decrease crippling postphelbitic syndrome by 70%

44. Pitfalls: emedicine
– Dismissing complaints of unexplained shortness of
breath as anxiety or hyperventilation without an
adequate workup
– Dismissing complaints of unexplained chest pain as
musculoskeletal pain without an adequate workup
– Failure to properly diagnose and treat symptomatic DVT
– Failure to recognize that DVT below the knee is just as
serious as more proximal DVT
– Failure to order a V/Q scan when a patient has
symptoms consistent with PE
– Failure to pursue the diagnosis after a V/Q scan that is
not perfectly normal
– Failure to start full-dose heparin at the first real
suspicion of PE, before the V/Q scan
– Failure to give fibrinolytic therapy immediately when a
patient with PE becomes hemodynamically unstable

45. References
 Marx, John MD, et al., Rosen's Emergency
Medicine: Concepts and Clinical Practice,
5th ed, Mosby, 2002.
 Tintinalli, Judith MD, et al., Emergency
Medicine:A Comprehensive Study Guide,
6th ed, McGraw-Hill, 2002.
 Feied, Craig MD, Pulmonary Embolism,
Emedicine.com, December 13, 2002.
 Nordenholz, Kristen MD, et al., Diagnostic
Strategies for Pulmonary Embolism,
Emergency Medicine, Vol. 36/Number 5,
May 2004.

46. Questions
1. 33 year old male with PMH of AT III deficency
c/o chest pain, left sided, pressure 4/10
radiating to the shoulder x 30 min. no
associated/alleving factors. HR 105, RR 24, BP
140/80. Which of the following is true for this
patient:
1. Fibrinolytics should be given if PE is confirmed
2. Heparin should be started immediately since PE is
strongly suspected
3. Enoxaparin is a better choice for anticoagulation since
it has better Xa:IIa ratio
4. Fibrinolytics should be considered only if RV
strain/dysfunction demonstrated
5. TNKase is the drug of choice

47. Answer
 Fibrinolytic therapy is mandatory for 3 groups of
patients: those who are hemodynamically
unstable, those with right heart strain and
exhausted cardiopulmonary reserves, and those
who are expected to have multiple recurrences of
pulmonary thromboembolism over a period of
years. Patients with a prior history of PE and
those with known deficiencies of protein C,
protein S, or antithrombin III should be included
in this latter group.
 Besides those for whom it is mandatory,
fibrinolysis should be considered as a potential
therapy for every patient with proven PE.
– Emedicine.com

48. Questions
2. A 34 year old obese G4 P3 female at 36 weeks
pregnancy and has a broken ankle complains of
shortness of breath and pleurtic chest pain x 30
minutes. This has never happened in her
previous pregnancies. Which of the following is
true:
1. Treat for PE only if the D-Dimer is greater than 500
ng/mL
2. Pregnancy is an absolute contraindiaction to fibrinolytics
3. Heparin should be started after obtaining imaging
studies that confirm VTE or PTE
4. A negative Quantitative ELISA D-Dimer rules out PE
5. A V/Q scan is the study of choice
6. Helical CTPA is not contraindicated
7. Negative serial bilateral venous ultrasonographic scan
rules out PE

49. Questions
3. A 45 year old female Complains of Chest pain. A
work up of PE is started. Data: CXR: infiltrate in
RLL EKG: NSR at 95 with RBBB and inferior
flipped Ts in II and III, ABG A-a gradient is 10,
WBC of 12, Cr 2.1, PT/PTT of 12/80.
1. Alteplace and aspirin should be given if PE on CT since
there is evidence of right heart strain
2. The A-a gradient rules out PE
3. Patient does not need anticoagulation
4. D-Dimer should be ordered regardless of pretest
probability
5. Pneumonia is not in the differential
6. Patient has an autoimmune disease

50. Questions
4. Which of the following statments is
correct:
1. Heparin exerts its effects on Factors II,VII,
IX,X, protein C, protein S
2. Lovenox has greater factor IIa effect than
heparin
3. An INR of greater than 3 is theraputic in
patients with hypercoagulability states
4. Fibrinoltics should be given concominately
with heparin
5. Aspirin should be given to patients with PE
6. Lepirudin is the first line treatment for Protein
C and Protein S deficiency

51. Questions
5. 35 year old male c/o R leg pain and swelling,
new onset chest pain x 30 minutes, and
shortness of breath. On exam the patient is
afebrile, tachycardic, tachypnic, hypotensive.
Patient has scleral icterus, crackles in the RUL,
bilateral pedal edema R>L and a positive
Homan’s sign and a positive psuedo-Homan’s
sign. Which statement acurately reflects this
patients condition:
1. Antibiotics given empirically
2. Heparin should be started prior to imaging studies since
PE is high on the differential
3. Fibrinolytics should be given due to unstable status
4. CT Angio prior to starting heparin
5. Budd-Chiari is not on the differential

52. UGH!