Pulmonary Thromboembolism (PTE)

An Elusive Diagnosis Jamil A. Alarafi, D.O.

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Goals

 Understand the historical context of pulmonary emboli  Comprehend the pathophysiology and know some common risk factors  Be aware of the clinical features of PE and have a basic understanding of various diagnostic test  Gain a therapeutic approach to the treatment of PE and discuss a simplified method in the work-up of PE  Attempt to dispel a few “myths”about pulmonary emboli 2

Perspective

 A Common disorder and potentially deadly  650,000 cases occurring annually  Highest incidence in hospitalized patients  Autopsy reports suggest it is commonly “missed” diagnosed 3

Perspective

 Presentation is often “atypical”  Signs and symptoms are frequently vague and nonspecific and rarely “classic”  Untreated mortality rate of 20% - 30%, plummets to 5% with timely intervention 4

Historical Context

 Pre-1930’s  Heparin  Eugine Robin article 5

Historical Context

 PIOPED (Prospective Investigation of Pulmonary Embolism Diagnosis)  The Electronic Era, 2000 and Beyond… 6

So What Do We Do ???



Confusing for Emergency Physician

Do we under diagnose/over diagnose?

Why don’t we have a standardized method of work up after all these years?

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Pathophysiology

Rudolph Virchow, 1858 Triad:    Hypercoagulability Stasis to flow Vessel injury 8

Risk Factors

Hypercoagulability

Malignancy Nonmalignant thrombophilia Pregnancy Postpartum status (<4wk) Estrogen/ OCP’s Genetic mutations (Factor V Leiden, Protein C & S deficiency, Factor VIII, Prothrombin mutations, anti-thrombin III deficiency)

Venous Statis

Bedrest > 24 hr Recent cast or external fixator Long-distance travel or prolong automobile travel

Venous Injury

Recent surgery requiring endotracheal intubation Recent trauma (especially the lower extremities and pelvis) 9

Clinical Presentation

 The Classic Triad: (

Hemoptysis, Dyspnea, Pleuritic Pain)

  Not very common!

Occurs in less than 20% of patients with documented PE  Three Clinical Presentations – – – Pulmonary Infarction Submassive Embolism Massive Embolism 10

Mythology of PE

 Myth – “Patients with pulmonary embolism are short of breath and have chest pain!”  Reality: You can forget about making the diagnosis on clinical grounds, but wait…don’t plan on completely ruling it out either!

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Clinical Features

Symptoms in Patients with Angio Proven PTE Symptom Dyspnea Chest Pain, pleuritic Anxiety Cough Hemoptysis Sweating Chest Pain, nonpleuritic Syncope Percent 84 74 59 53 30 27 14 13 12

Clinical Features

Signs with Angiographically Proven PE Sign Tachypnea > 20/min Rales Accentuated S2 Tachycardia >100/min Fever > 37.8

Diaphoresis S3 or S4 gallop Thrombophebitis Lower extremity edema Percent 92 58 53 44 43 36 34 32 24 13

Who do we work up?

-

Pretest Probability  Definition: “The probability of the target disorder (PE) before a diagnostic test result is known”.

 Used to decide how to proceed with diagnostic testing and final disposition 

“Gestalt”

– This is really what it boils down to!

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Diagnostic Test

 Imaging Studies – CXR – V/Q Scans – Spiral Chest CT – Pulmonary Angiography – Echocardiograpy  Laboratory Analysis – CBC, ESR, Hgb/Hct, – D-Dimer – ABG’s  Ancillary Testing – EKG – Pulse Oximetry 15

Diagnostic Testing

CXR’s Chest X-Ray Myth: “You have to do a chest x-ray so you can find Hampton’s hump or a Westermark sign.” Reality: Most chest x-rays in patients with PE are nonspecific and insensitive 16

Diagnostic Testing -

CXR’s Chest radiograph findings in patient with pulmonary embolism

Result

Cardiomegaly Normal study Atelectasis Elevated Hemidiaphragm Pulmonary Artery Enlargement Pleural Effusion Parenchymal Pulmonary Infiltrate

Percent

27% 24% 23% 20% 19% 18% 17% 17

Chest X-ray Eponyms of PE

 Westermark's sign – A dilation of the pulmonary vessels proximal to the embolism along with collapse of distal vessels, sometimes with a sharp cutoff.  Hampton’s Hump – A triangular or rounded pleural-based infiltrate with the apex toward the hilum, usually located adjacent to the hilum.

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Radiographic Eponyms

Hampton’s Hump, Westermark’s Sign Westermark’s Sign Hampton’s Hump 19

Diagnostic Testing

– EKG’s  EKG – Most Common Findings:  Tachycardia or nonspecific ST/T-wave changes – Acute cor pulmonale or right strain patterns     Tall peaked T-waves in lead II (P pulmonale) Right axis deviation RBBB S1-Q3-T3 (occurs in only 20% of PE patients) 20

Diagnostic Testing -

Pulse Oximetry  The Pulse Oximetry Myth: – “ You must do a pulse oximetry reading, since patients with pulmonary embolism are hypoxemic!”  Reality: – Most patients with a PE have a normal pulse oximetry, and most patients with an abnormal pulse oximetry will not have a PE.

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Diagnostic Testing

ABG’s  The ABG/ A-a Gradient myth: – “You must do an arterial blood gas and calculate the alveolar arterial gradient. Normal A-a gradient virtually rules out PE”.

 Reality: – The A-a gradient is a better measure of gas exchange than the pO2, but it is nonspecific and insensitive in ruling out PE.

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Diagnostic Testing

 Echocardiography – Consider in every patient with a documented pulmonary embolism  EKG maybe helpful in demonstrating right heart strain – Early fibrinolysis can reduce mortality 50%!

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Ancillary Test

 WBC – Poor sensitivity and nonspecific  Can be as high as 20,000 in some patients  Hgb/Hct – PTE does not alter count but if extreme, consider polycythemia, a known risk factor  ESR – Don’t get one, terrible test in regard to any predictive value 24

D-dimer Test

 Fibrin split product  Circulating half-life of 4-6 hours  Quantitative test have 80-85% sensitivity, and 93-100% negative predictive value  False Positives: Pregnant Patients Malignancy Advanced age > 80 years Hemmorrhage AMI Hepatic Impairment Post-partum < 1 week Surgery within 1 week Sepsis CVA Collagen Vascular Diseases 25

Diagnostic Testing

 D-dimer – Qualitative  Bed side RBC agglutination test – “SimpliRED D-dimer” – Quantitative  Enzyme linked immunosorbent asssay “Dimertest”  Positive assay is > 500ng/ml  VIDAS D-dimer, 2 nd generation ELISA test 26

Ventilation/Perfusion Scan “V/Q Scan”  A common modality to image the lung and its use still stems from the PIOPED study.

 Relatively noninvasive and sadly most often nondiagnostic  In many centers remains the initial test of choice  Preferred test in pregnant patients  50 mrem vs 800mrem (with spiral CT) 27

V/Q Scan



Technique

 – – –

Interpretation

Normal Low probability/”nondiagnostic” (most common) High Probability 

Simplified approached to the interpretation of results:

High probability Normal Scan Everything else    Treat for PE If low pre-test, your done Purse another study (CT, Angio) 28

Spiral (Helical) Chest CT

 Advantages – Noninvasive and Rapid – Alternative Diagnosis  Disadvantages – Costly ($600 - 900/scan) – Risk to patients with borderline renal function – Hard to detect subsegmental pulmonary emboli 29

Pulmonary Angiography

 “Gold Standard” – Performed in an Interventional Cath Lab  Positive result is a “cutoff” of flow or intraluminal filling defect  “Court of Last Resort” 30

Treatment:

Dr. Batizy explaining the CT results Patient replies: “Uh-huh, when do I get to eat!” Goals:  Prevent death from a current embolic event  Reduce the likelihood of recurrent embolic events  Minimize the long-term morbidity of the event 31

Treatment

 Anticoagulants – Heparin  Provides immediate thrombin inhibition, which prevents thrombus extension  Does not dissolve existing clot  Will not work in patients with antithrombin III def.

– In this case use hirudins  Few absolute contraindications 32

Treatment

 Anticoagulants – Heparin  Available as Unfractionated or LMW Heparin – FDA approved dosing: • Unfractionated: 80 units/kg bolus, 18 units/kg/hr • LMWH: 1 mg/kg Q 12 or 1.5mg/kg Q D  LMWH (Lovenox) prefered in pregnant patients 33

Treatment

 Anticoagulants – Warfarin (Coumadin)  Interferes with the action of Vit-K dependent factors: II, VII, IX, and X, as well as protein C & S  Causes temporary hypercoagulable state in first 5 days of treatment – Important a patient is anticoagulated with heparin before initiating warfarin therapy  Target INR is 2.5 – 3.0 34

Treatment

 Fibrinolytic Therapy (Alteplase) – Indications:  Documented PE with: – Persistent hypotension – Syncope with persistent hemodynamic compromise – Significant hypoxemia – +/- patient with acute right heart strain  Approved Altivase regimen is 100mg as a continuous IV infusion.

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Treatment

 Embolectomy – Prefininolytic therapy this was only therapy for massive PE – Carries a 40% operative mortality – Alternative is Transvenous Catheter Embolectomy 36

A Simplified Algorithm

 Pre-test probability  D-dimer (VIDAS-DD)  CT angiography Low Pre-test, D-dimer (-), patient had < 1.7% 90 day PE occurrence in a Mayo Clinic Study 37

Special Circumstances

 Morbid Obesity  Pregnancy  V/Q has considerable less radiation – 50 mrem vs. 800 mrem  Almost all will have positive D-Dimer  Heparin safe in pregnancy  Witnessed Cardiac Arrest  Standard ACLS, if known PE, the lytics.

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Conclusion

Summary Points  Pulmonary Emboli remain a potentially deadly and common event which may present in various ways  Don't’ be fooled if your patient lacks the “classic” signs and symptoms!

 Consider PE in any patient with an unexplainable cause of dyspnea, pleuritic chest pain, or findings of tachycardia, tachpnea, or hypoxemia  2 nd Generation Qualitative D-Dimers have NPV of 93-99%  Heparin remains the mainstay of therapy with the initiation of Warfarin to follow  Simplified Algorithm: ( Pretest probability, D-Dimer, +/- CT angio), then disposition) 39

The End!

Questions????

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1. Which of the following is not a part of virchows triad?

a) Hypercoagulability b) c) d) Stasis to flow Vessel injury History of previous DVT 41

2.

Which of the following is the propper treatment of fat emboli?

a) Platelets b) High dose steroids c) Heparin d) cryoprecipitate 42

a) b) c) d)

3.

The Classic Triad of patients presenting to the ED with PE includes all of the following except:

Hemoptysis Dyspnea + Homans’ sign Pleuritic Pain

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a) b) c) d) 4.

What is the most common symptom in a patient with Angio Proven PTE?

Dyspnea Chest Pain, pleuritic Anxiety Cough 44

5.

What is the most common ecg finding in patients with PE?

a) b) c) d) e) Right axis deviation RBBB S1-Q3-T3 Tall peaked T-waves in lead II (P pulmonale) Sinus tachycardia 45

Answers

1.

2.

3.

4.

5.

D B C A E 46