Transcript Slide 1

Post-Op Pulmonary Embolism
Linda P. Zhang, MS III
Scott Q. Nguyen, M.D.
Celia M. Divino, M.D.
Mount Sinai School of Medicine
Mrs. Margo
 Your patient in the hospital is a 62 year- old
female with a 1 hour history of shortness of
breath, s/p a right total hip replacement 4 days
ago.
History
What other points of the history do
you want to know?
History, Mrs. Margo
Consider the following:
 Characterization of Symptoms: 
New sudden onset SOB and
tachypnea while lying in bed. Pain 
with breathing. Intermittent cough
with no hemoptysis. Feeling of
apprehension.

 Temporal sequence
Total hip replacement 4 days prior, 
no complications since surgery.
Has not been ambulating since
surgery.
Alleviating/Exacerbating factors:
Aggravated by breathing
Pertinent PMH
L breast cancer, s/p modified radical
mastectomy and radiation 2 yr ago.
ROS: no palpitations, no peripheral
edema.
MEDS: Percocet
Differential Diagnosis ?
Differential Diagnosis
Based on History and Presentation
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Pulmonary embolism
Aspiration pneumonitis
Myocardial infarction
Heart failure / Pulmonary Edema
Pneumothorax
ARDS
Physical Examination
What would you look for?
Physical Examination, Mrs. M
 Vital Signs: T 37.5, pulse 105, BP 135/85, RR 26,
 O2 Sat: 89% Room air
 Appearance: AAOx3, anxious
Chest: CTAB
CV: RRR, tachycardic, accentuated P2. (+) S4
Abd: normo-active bowel sound, soft, nontender non-distended
Rectal: guaiac negative
Extremities: No thigh or calf swelling. No localized tenderness or
erythema along veins. (-) calf pain upon passive dorsiflexion of feet (what
sign is this?). No clubbing/edema/cyanosis
Remaining Examination findings non-contributory
Would you like to revise your
Differential Diagnosis?
Revised Differential Diagnosis
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Pulmonary Embolism
Heart Failure / Pulmonary Edema
MI
Aspiration pneumonitis
Laboratory
What would you obtain?
Labs ordered, Mrs. Margo
CBC: Hb/Hematocrit/WBC
PT/PTT/ Platelets
ABG
Cardiac Enzymes
Lab Results, Mrs. Margo
CBC: Hb
Hematocrit
WBC
13.3
37
12.1
PT/PTT/Platelet:
11/24/375
ABG:
7.48/27/55 O2 sat 89%
Cardiac enzyme:
Troponin 1.2
Lab Results, Discussion
 CBC: can be done to r/o elevated WBC secondary to
pulmonary infection, and to r/o decreasing H/H secondary to
occult bleeding.
 ABGs: can be done to determine acid-base imbalance and to
r/o pulmonary or renal disease.
• Hypoxemia, hypocapnia, respiratory alkalosis secondary to
tachypnea, and ↑ A-a gradient may suggest PE.
• However, massive PE with respiratory collapse can present as
hypercapnia and combined respiratory and metabolic acidosis.
 Troponin I and T: can do done to r/o MI. May be elevated
in moderate to large PE secondary to acute right heart
overload.
Interventions at this point?
Interventions at this point?
 Supplemental Oxygen
Studies
What further studies would you want at this
time?
Studies, Mrs. Margo
 EKG
 Chest x-ray
EKG, Discussion
 EKG:
• Can be used to r/o arrhythmias, ischemia, MI,
and axis-deviation.
• For PE: see tachycardia, R axis deviation and
nonspecific ST and T wave changes.
− Classic findings of S wave in Lead I, Q wave in Lead III,
and T wave inversion in Lead III seen in <20% of cases.
− May also see RBBB, P pulmonale, atrial fib.
Chest x-ray, Discussion
Chest x-ray, Discussion
 Chest x-ray:
 Can be used to r/o pneumothorax, ARDS, pneumonia.
 For PE, abnormal chest x-ray findings are common but
nonspecific: atelectasis, pleural effusion, infiltrates. May see
Hampton’s hump or Westermark’s sign. In most cases, the
CXR will be clear.
 Cardiomegaly is a common radiographic finding in PE
Intervention at this point?
Intervention at this point?
 Start therapeutic-dose heparin:
• Given the strong clinical suspicion for PE, it may be
necessary to start heparin prior to initiating any
diagnostic studies.
• Must watch out for post-surgical bleeding when
patient is placed on heparin.
What next?
To diagnose PE (initial study):
V/Q scan, Discussion
Initial diagnostic tool for PE:
 V/Q scan:
 The most frequently used test in diagnosing PE.
 Advantages: Noninvasive
 Disadvantages:
− diagnostic value is dependent on the result:
•A normal V/Q scan = 5% chance of patient having PE
•A high probability V/Q scan = 85% chance of patient having PE
•An intermediate or low probability V/Q scan = non-diagnostic, a
pulmonary angiogram is needed for definitive diagnosis.
− In over 50% of cases, the V/Q scan result will be either intermediate or low
probability, thus rendering the result non-diagnostic.
− Not always readily available as a diagnostic test.
VQ picture
Low Probability Ventilation Perfusion Scan
Studies – Results for Mrs. Margo
 V/Q scan result:
• Intermediate probability scan
What is the differential diagnosis at this
point?
Revised Differential Diagnosis
 Pulmonary Embolism
 Possible early MI
What next?
What Next?
 CT angiography
CT angiography, Discussion
 CT angiography
 Frequently used as follow-up test after a non-diagnostic V/Q scan.
 Advantages:
• Noninvasive, but requires contrast. Do not give for patients with renal
insufficiency/failure.
• Readily available test.
• Sensitivity and specificity greater than 90%.
 Disadvantages:
• Can detect emboli in proximal pulmonary arteries and segmental
arteries, but very limited in detection of emboli beyond segmental
arteries.
• Immediate post-op PE are fresh clots that are easily fragmented, and
thus more likely to be found in the periphery. As such, CT angio
would not be a good diagnostic tool for immediate post-op PE.
• Technician- and reader-dependent. Positive and negative results must
be interpreted with caution.
• Difficult to see obliquely/horizontally oriented vessels within the
right middle lobe and left lingula.
CT angiography of PE
Large clot in Right
pulmonary artery (arrow).
Other studies, Discussion
There are multiple other diagnostic tools that can be used to
help diagnose PE:
 Pulmonary Angiography
• Considered the historical gold standard for diagnosing PE
• On image, see a filling defect or sharp cutoff of small vessels.
• Advantages:
 Best diagnostic yield. If negative result, PE can be excluded from differential.
• Disadvantages:
 Invasive, and requires contrast.
 Patients who have long-standing pulmonary arterial hypertension and right
ventricular failure should not undergo a pulmonary angiography.
• Pulmonary angiography should be the initial test for critically ill patients.
It should be obtained immediately after clinical episode. Otherwise, it may
result in a false negative.
Other studies, Discussion
 Venography/duplex ultrasound
• For stable patients with suspect PE and adequate cardiopulmonary reserve (absence
of hypotension or severe hypoxemia), a duplex ultrasound can be done to rule in
DVT if the V/Q scan was inconclusive.
• Advantages:
‾ Noninvasive. Easily available. Fast
• Disadvantage:
‾ High sensitivity (89-100%) and specificity (89-100%) for detection of
proximal DVT in symptomatic patients. However, in patients without
symptoms of DVT, sensitivity is only 38% and positive predictive value is
26%.
‾ If suspect PE but duplex scan is negative, must perform follow-up imaging. If
positive scan for DVT, start anticoagulation
 D-dimer:
• Rarely helpful in diagnosing PE in patients with recent surgery
• In non-post-op situations where D-dimer is done, PE can be excluded from the
differential if D-dimer result is negative (negative predictive value of 95%). If the
result is positive, further workup needs to be done.
Doppler Venous US
Normal Common Femoral Vein by Doppler US
Management
Initial Management, Mrs. Margo
 After initial intervention of heparin and
supplemental oxygen:
• RR decreased to 18 breaths per minute
• O2 sat increased to 93%
What should be done next?
Management, Mrs. Margo
 Unfractionated heparin –
• Continue for next 7 days
• Maintain PTT level between 46-70 sec
 Warfarin –
• Give warfarin simultaneously with heparin
• Maintain INR between 2.0-3.0
 Long term management: continue warfarin for 6
months.
PE Management, Discussion
PE management focuses on preventing further blood clot
formation, lysis of current clot, and prevention of
recurrent PE.
 Initial intervention: unfractionated heparin or low
molecular weight heparin:
• Unfractionated heparin: IV, PTT should be 46-70 secs (1.5-2.3 x’s the
control)
• LMWH: SQ, greater bioavailability, fixed dose, QD or BID, no need to
monitor PTT
• LMWH is equally effective as unfractionated heparin in treatment of
PE.
• Complications: retroperitoneal bleeding, intracranial bleeding, heparininduced thrombocytopenia (HIT)
PE Management, Discussion
 Addition of oral anticoagulant: Warfarin
• Initiate at the same time as heparin, or after diagnosis of PE.
• Overlap with heparin for at least 5 days and continue until
INR is within therapeutic range for 2 consecutive days before
discontinuing heparin.
• Maintain INR between 2.0-3.0. Must check INR 2x/wk for
1st few weeks, once weekly for next several months, and once
monthly thereafter if patient is stable.
PE Management, Discussion
 Long term prophylaxis: Warfarin
• For 1st PE event with reversible or time-limited risk
factor (i.e. surgery, immobilization, trauma),
continue warfarin for 3-6 months.
• For idiopathic 1st thromboembolic event, continue
warfarin for at least 6 mos.
• For 2nd PE event, cancer, non-modifiable risk
factors, continue warfarin for at least 12 mos or
indefinitely.
Hospital Course, Mrs. Margo
 Pt remains clinically stable, with only mild
hypoxemia for the remainder of that day. No
signs of right ventricular failure.
 Pt recovers uneventfully, and is discharged
home on Day 10 with warfarin for 6 months.
Discussion
Epidemiology:
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Pulmonary embolism occurs in over 500,000 patients in the US annually, resulting
in approximately 200,000 deaths. Without prophylaxis, 4-7% of patients with hip
surgery will die of PE. Untreated PE results in approximately 30% mortality rate.
Patients presenting with PE who survive the initial insult usually die from recurrent
PE during the initial treatment period.
Pathophysiology:
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Significant PE are generally from thrombosis formation from deep veins of the
thigh and pelvis. Large thrombi, after dislodging from DVT, travel to the lung and
become lodged at the main pulmonary artery or lobar branches, causing
hemodynamic compromise. Small thrombi travel to distal areas of lung, producing
pleuritic pain secondary to inflammatory response by parietal pleura.
Only 10% of PE cause pulmonary infarction.
Most PE are multiple and are more likely to travel to lower lobes
Risk factors: immobilization, surgery within last 3 months, malignancy, stroke, and
history of venous thromboembolism, Factor V Leiden mutation, Protein C and
Protein S deficiency, or Antithrombin III deficiency.
Discussion
Minor PE
 Patients with minor PE can present with transient dyspnea and cardiac
irritability, which may resolve in a few moments. The onset of symptoms
can be immediately post surgery to 7 days post-op. If patient is considered
to be at substantial risk and anticoagulation is not contraindicated, heparin
therapy can be given while diagnostic tests are being ordered. If
anticoagulation may be risky and/or PE seems unlikely, a D-dimer can be
performed (in cases of non-post-operative patients). A negative result
excludes PE from the differential. If the result is positive, a pulmonary
angiography must be done to confirm the diagnosis of PE. In the meantime,
heparin therapy should be continued.
 If PE occurred within 10 days after surgery, a D-dimer test can give a false
positive result. As such, a pulmonary angiography should be obtained.
 For critically ill patients who do not tolerate diagnostic tests well,
pulmonary angiography should be the initial study.
Discussion
Moderate PE
 Patients with moderate PE will present with transient hypotension,
tachycardia, cardiac dysrhythmia, apprehension, tachypnea with ↓ O2 and ↑
CO2, and possible signs of pulmonary infarction. EKG will show acute
right axis deviation, nonspecific ST and T wave changes, and possible
RBBB. Initial intervention with heparin therapy should be started in
patients where diagnosis is probable and where there are no likely
alternative diagnoses. Consider lytic therapy for patients without recent
surgery or vascular injury.
 A D-dimer can be done in non-post-operative patients to rule out PE. If the
result is positive, a pulmonary angiography should be done to confirm the
diagnosis.
 If a diagnosis of PE is not confirmed by pulmonary angiography but patient
has risk factors for PE, prophylactic-dose heparin should be continued.
 With a confirmed diagnosis of PE, continue heparin and add warfarin for
long-term treatment. If anticoagulation is contraindicated, consider an IVC
filter.
Discussion
Catastrophic PE
 Patients with catastrophic PE will present with cardiac arrest,
brady-arrhythmia, severe hypotension, circulatory collapse, or
left heart failure. It generally occurs 7-10 days after injury or
onset of clinical illness, when the embolus has matured and is
resistant to lysis. A large embolus is usually mobilized after
patient performs a Valsalva maneuver, resulting in immediate
circulatory collapse and cardiac arrest.
 Treatment consists of intubation with 100% oxygen,
cardiotonic agents, and large doses of heparin.
• Consider Trendelenburg’s procedure (rarely performed and rarely
successful) or cardiopulmonary bypass
• If patient survives initial resuscitation, continue heparin and consider
lytic therapy or IVC filter.
• Survival rate is minimal.
Discussion
Other PE management options
 Thrombolytics: t-PA, streptokinase, urokinase.
• Contraindicated in patients with surgery in previous 10
days, active bleeding, previous cerebrovascular accident,
serious GI bleed in previous 3 mos.
• Given for hemodynamically unstable PE. Most effective
when initiated within hours.
• Should discontinue heparin while giving lytic therapy,
unless there is a life-threatening clot.
Discussion
Other PE management options
 Inferior vena cava filter - indicated if:
• Patient has an absolute contraindication to
anticoagulant therapy (eg. recent surgery,
hemorrhagic stroke, significant recent/active
bleeding)
• Patients with a history of massive PE in whom a
recurrent embolism may be fatal
• Recurrent DVT during adequate anticoagulant
therapy
IVC Filter
QUESTIONS ??????
Summary
 PE carries a high mortality rate and should be high on the
differential for patients presenting with sudden shortness of
breath.
 If anticoagulant therapy is not contraindicated, therapeuticheparin should be initiated early with suspected PE.
 V/Q scan, CT angiography, and D-dimer are diagnostic tools
for PE, however, each test has their own advantages and
disadvantages.
 Pulmonary angiography continues to be the gold standard for
diagnosing PE.
 Management of PE consists of initiating heparin and warfarin
simultaneously for the first 5-7 days, followed by long-term
treatment and prophylaxis with outpatient warfarin for 3
months, 6 months, or indefinitely depending on patient’s risk
factors for recurrent PE.
Acknowledgment
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