Pulmonary Embolism- Diagnosis by Dr.Tinku Joseph
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Transcript of Pulmonary Embolism- Diagnosis by Dr.Tinku Joseph
PULMONARY EMBOLISMDIAGNOSIS
Dr.Tinku JosephDM Resident
Dept. Of Pulmonary MedicineAIMS, Kochi.
Diagnostic Tests Imaging Studies– CXR– V/Q Scans– Spiral Chest CT– Pulmonary Angiography– Echocardiograpy
Laboratory Analysis– CBC, ESR, – D-Dimer– ABG’s
Ancillary Testing– ECG– Pulse Oximetry
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 Post-partum < 1 weekMalignancy Surgery within 1 weekAdvanced age > 80 years SepsisHemmorrhage CVA
Collagen Vascular DiseasesHepatic Impairment
Arch Intern Med 2004;140:589
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, 2nd generation ELISA
test
D-DIMER• False Positive D-Dimer– Pregnancy– Trauma– Postoperative Recovery– Inflammation– Cancer– Rheumatoid Factor– Older Age
• False Negative D-Dimer– Heparin
Prognostic Value of Troponins in AcutePulmonary Embolism
Conclusion: Elevated troponin levels were associated with a high risk of (early) death resulting from pulmonary embolism (OR, 9.44; 95% CI, 4.14 to 21.49)
These findings identify troponin as a promising tool for rapid risk stratification of patients with pulmonary embolism.
BNP & pro-BNP
Typically greater in patients with PE. Sensitivity of 60% and specificity of 62%. At a threshold of 500 pg/mL, the sensitivity of pro-
BNP for predicting adverse events was 95%, and the specificity was 57%.
Kucher N et al. Low pro-brain natriuretic peptide levels predict benign clinical outcome in acute pulmonary embolism. Circulation 2003 Apr 1; 107:1576-8.
WBC Poor sensitivity and nonspecific
Can be as high as 20,000 in some patients
Hb 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
Doppler ultrasound of leg veins
Principle - Veins are normally compressible; Presence of DVT renders veins non-compressible50% of patients with PE have positive ultrasound(95% of PE are due to leg DVT)
ECG
– 2 Most Common finding on ECG: Nonspecific ST-segment and T-wave changes Sinus Tachycardia
– Historical abnormality suggestive of PE S1Q3T3 Right ventricular strain New incomplete RBBB
Echocardiography
This modality generally has limited accuracy in the diagnosis.
The overall sensitivity and specificity for diagnosis of central and peripheral pulmonary embolism by ECHO is 59% and 77%.
It may allow diagnosis of other conditions that may be confused with pulmonary embolism.
ECHO signs of PE
RV enlargement or hypokinesis especially free wall hypokinesis, with sparing of the apex (the McConnell sign)
60/60 Sign- Acceleration time of RV ejection <60ms in the presence of TR pressure gradient </= 60mmHg.
Interventricular septal flattening and paradoxical motion toward the LV resulting in a “D-shaped” LV in cross section.
Tricuspid regurgitation
Echocardiography
Am J Med 122:257,2009
Echocardiogram in PE
ABG analysis
ABG has a limited role. It usually reveal hypoxemia,
hypocapnia and respiratory alkalosis.
Alveolar arterial oxygen gradient , done at room air, a-a gradient > 15-20 is considered abnormal.
Chest x ray
A normal or nearly normal chest x-ray
Chest Xray
Chest radiograph findings in patient with pulmonary embolism
Result PercentCardiomegaly 27%Normal study 24%Atelectasis 23% Elevated Hemidiaphragm 20%Pulmonary Artery Enlargement 19%Pleural Effusion 18%Parenchymal Pulmonary Infiltrate 17%
Am Heart J 1997;134:479-87
Radiographic signs of acute pulmonary embolism
Signs with relative high specificity but low sensitivity for acute pulmonary embolism:
Decreased vascularity in the peripheral lung (Westermark sign).
Enlargement of the central pulmonary artery (Fleischner sign).
Enlarged right descending pulmonary artery (Palla's sign)
Pleural based areas of increased opacity (Hampton hump).
Hemidiaphragm elevation.
Non specific signs associated with acute pulmonary embolism that may be associated with other diseases:
Focal area of increased opacity. Linear atelectasis. Pleural effusion.
Radiographic signs of acute pulmonary embolism
Westermark’s sign
Westermark sign, with hilar enlargement
Dilatation of pulmonary vessels proximal to embolism along with collapse of distal vessels, often with a sharp cut off.
Hampton’s hump
Hampton’s hump
Dome shaped pleural based opacity due to lung infarction.
Pulmonary infarct is dome shaped instead of being wedge shaped because of double blood supply with preserved bronchial arteries resulting in sparing of the expected apex of the wedge.
Radiographic Eponyms- Hampton’s Hump, Westermark’s Sign
Westermark’s Sign
Hampton’s Hump
Ventilation/Perfusion Scan- “V/Q Scan”
A common modality to image the lung.
Relatively noninvasive.
In many centers remains the initial test of choice
Preferred test in pregnant patients 50 mrem vs 800mrem (with spiral CT)
V/Q ScanVQ scan
Technique
NormalVentilation
Left UL PE
Perfusion scanVentillation scan
Ventilation/Perfusion Scan
HIGH PROBABILITY (>80%): 2 or more large mismatched segments or the equivalent.
any perfusion defect substantially larger than radiographic abnormality
INTERMEDIATE PROBABILITY (20-79%): 1 moderate to 2 large mismatched segments
LOW PROBABILITY (<20%): Non-segmental perfusion defects, matched defects
NORMAL: no perfusion defects
PIOPED: PREDICTIVE VALUE V/Q SCAN
SCAN CATEGORY CLINICAL SUSPICION
80-100% 20-79% 0-19%
HIGH
INTERMEDIATE
LOW
PIOPED INVESTIGATORS. JAMA.1990; 263: 2753-2759
VQ Scan
Spiral CT Major advantage of Spiral CT is speed: Often the patient can hold their breath for
the entire study, reducing motion artifacts. Allows for more optimal use of intravenous
contrast enhancement. Spiral CT is quicker than the equivalent
conventional CT permitting the use of higher resolution acquisitions in the same study time.
Contraindicated in cases of renal disease. Sensitive for PE in the proximal pulmonary
arteries, but less so in the distal segments.
CT Angiogram
Quickly becoming the test of choice for initial evaluation of a suspected PE.
CT unlikely to miss any lesion. Better sensitivity, specificity and can be used directly
to screen for PE. Used to follow up “non diagnostic V/Q scans.
CT Angiogram
Chest computed tomography scanning demonstrating extensive embolization of the pulmonary arteries.
Multidetector Helical CT Pulmonary Angiography
Multidetector Helical CT Pulmonary Angiography Advantages
Multidetector Helical CT Pulmonary Angiography Limitations
CT findings of acute pulmonary embolism
Vascular abnormalities: Intraluminal filling defects that forms an acute
angle with the vessel wall & may be surrounded by contrast material (polo mint sign or railway sign).
Total cutoff of vascular enhancement. Enlargement of the occluded vessel.Ancillary findings: Pleural based wedge shaped areas of increased
attenuation with no contrast enhancement. Linear atelectasis.
Partial eccentric filling defect with acute angle with the vessel wall
Intraluminal filling defect(polo mint sign)
Intraluminal filling defect(railway track sign)
Enlargment of the occluded vessel
Ancillary findings of acute pulmonary embolism(atelectatic band)
MRA
MRA
Pulmonary angiogram
Gold Standard. Positive angiogram provides 100% certainty that an
obstruction exists in the pulmonary artery. Negative angiogram provides > 90% certainty in the
exclusion of PE. “Court of Last Resort”
Pulmonary angiogram
Left-sided pulmonary angiogram showing extensive filling defects within the left pulmonary artery and its branches.
Angiographic severity scoring
Miller, et al. Amer Journ Roent,Rad Therapy & Nuc Med. 125(4):895-9, 1975 Dec.
Further Alternative Imaging Tests (Newer modalities)
Dual-energy CTPA
Electrocardiographically gated CTPA
Three-dimensional images acquired by single-photon emission computed tomography (SPECT) using a gamma-emitting radioisotope may improve V/Q scintigraphy and has a lower radiation dose.
Dual-energy CTPA
Provides functional and anatomic lung imaging Demonstrates perfusion defects beyond obstructive and non-obstructive clots Diagnostic accuracy requires further research
Advantages Indirect evaluation of peripheral pulmonary arterial bed Disadvantages Longer data acquisition time Increased radiation exposure
Dual-energy CTPA
[A] Axial reconstruction with color-coded dual energy perfusion information. Note the large perfusion defects in both lungs.
[B] Coronal reconstruction. Only the apical parts show a normal perfusion.
Electrocardiographically gated CTPA
Can differentiate between cardiac events and PE
May be of use in patients presenting with thoracic pain and suspected PE, cardiac events, or aorta dissection.
More contrast material is needed, and the radiation dose is higher compared with CTPA.
Imaging in Pregnancy
No validated clinical decision rules No consensus in evidence for diagnostic imaging algorithm Balance risk of radiation vs. risk of missed fatal diagnosis or
unnecessary anticoagulation MDCT delivers higher radiation dose to mother but lower
dose to fetus than V/Q scanning Consider low-dose CT-PA or reduced-dose lung scintigraphy
Stein P et al. Radiology. 2007 Jan;242:15-21.Marik PE; Plante LA. N. Engl. J. Med. 2008;359:2025-33.
Imaging-nut shell
Plain chest radiograph – Usually normal and non-specific signs.
Radionuclide ventilation-perfusion lung scan – Excellent negative predictive value.
CT Angiography of the pulmonary arteries – Quickly becoming method of choice.
Pulmonary angiography – Gold standard but invasive.
Diagnostic Tests for Suspected Pulmonary Embolism
Oxygen saturation Nonspecific, but suspect PE if there is a sudden, otherwise unexplained decrement
D-dimer An excellent “rule-out” test if normal, especially if accompanied by non–high clinical probability
Electrocardiography May suggest an alternative diagnosis, such as myocardial infarction or pericarditis
Lung scanning Usually provides ambiguous result; used in lieu of chest CT for patients with anaphylaxis to contrast agent, renal insufficiency, or pregnancy
Chest CT The most accurate diagnostic imaging test for PE ; beware if CT result and clinical likelihood probability are discordant
Pulmonary angiography Invasive, costly, uncomfortable; used primarily when local catheter intervention is planned
Echocardiography Best used as a prognostic test in patients with established PE rather than as a diagnostic test ; many patients with large PE will have normal echocardiograms
Venous ultrasonography Excellent for diagnosis of acute symptomatic proximal DVT; a normal study does not rule out PE because a recent leg DVT may have embolized completely; calf vein imaging is operator dependent
Magnetic resonance Reliable only for imaging of proximal segmental pulmonary arteries; requires gadolinium but does not require iodinated contrast agent
Pulmonary Embolism(Treatment) Part 2
Dr.Tinku JosephDM Resident
Dept. Of Pulmonary MedicineAIMS, Kochi.
Approach to the patient of PE
Stratify patients into high clinical likelihood or non–high clinical likelihood of PE .
In low-risk group, only about 5% of patients were subsequently diagnosed with PE.
How 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
Classic Wells Criteria to Assess Clinical Likelihood of Pulmonary Embolism
SCORE POINTS
DVT symptoms or signs 3
An alternative diagnosis is less likely than PE
3
Heart rate >100/min 1.5
Immobilization or surgery within 4 weeks
1.5
Prior DVT or PE 1.5
Hemoptysis 1
Cancer treated within 6 months or metastatic
1
>4 score points = high probability ≤4 score points = non–high probability JAMA 295:172,2006
Simplified Wells Criteria to Assess Clinical Likelihood of Pulmonary Embolism
DVT symptoms or signs 1
An alternative diagnosis is less likely than PE
1
Heart rate >100/min 1
Immobilization or surgery within 4 weeks
1
Prior DVT or PE 1
Hemoptysis 1
Cancer treated within 6 months or metastatic
1
>1 score point = high probability ≤1 score point = non–high probability
Thromb Haemost 101:197,2009
Original Geneva score
Revised Geneva score
ACC/AHA Classification
• Massive• Submassive• Low-Risk PE• Pulmonary infarction syndrome
Massive PE
• Acute PE with sustained hypotension (systolic blood pressure 90 mm Hg for at least 15 minutes or requiring inotropic support, not due to a cause other than PE, such as
Arrhythmia Hypovolemia Sepsis Left ventricular (LV) dysfunction Pulselessness Persistent profound bradycardia (heart rate 40 bpm with
signs or symptoms of shock)
Submassive PE• Acute PE without systemic hypotension (systolic blood pressure 90mm Hg)
but with either RV dysfunction or myocardial necrosis• RV dysfunction means the presence of at least 1 of the following RV dilation (apical 4-chamber RV diameter divided by LV diameter 0.9) or
RV systolic dysfunction on echocardiography RV dilation (4-chamber RV diameter divided by LV diameter 0.9) on CT Elevation of BNP (90 pg/mL) Elevation of N-terminal pro-BNP (500 pg/mL) Electrocardiographic changes (new complete or incomplete right bundle-
branch block, anteroseptal ST elevation or depression, or anteroseptal T-wave inversion)
Torbicki A et al. Eur Heart J 29(18):2276–2315, 2008
Low-Risk PE
• Acute PE and the absence of the clinical markers of adverse prognosis that define massive or submassive PE
Pulmonary Infarction Syndrome
• Caused by a tiny peripheral pulmonary embolism Pleuritic chest pain, often not responsive to
narcotics Low-grade fever Leukocytosis Pleural rub Occasional scant hemoptysis
Treatment:
Goals:
Prevent death from a current embolic event
Reduce the likelihood of recurrent embolic events
Minimize the long-term morbidity of the event
Treatment options Symptomatic treatment:
– ABCD approach– Oxygen– Analgesia
Anticoagulation:– IV Heparin– S/C LMWH eg Enoxaparine, Dalteparine– Oral Warfarin
IVC filter: If there is contra-indications for anti-coagulation
Thrombolysis: tPA eg Alteplase, Tenectaplase
Surgical procedures: Pulmonary embolectomy
Treatment options
Massive PE: Thrombolysis/embolectomy
Sub-massive PE: Strongly consider thrombolysis/embolectomy but need to balance risk of bleeding
Non-massive PE: Anticoagulation
KEY STUDIES & guidelines IN PE TREATMENT
• 1937 Murry: first use of heparin• 1960 Barritt:“RCT” warfarin vs. placebo• 1968 Sasahara: UPET• 2003 Konstantinides: Alteplase
Prevention
ACCP guide lines• For acutely ill hospitalised medical pts at low risk of
thrombosis ACCP recommends against the use of prophylaxsis.
• Pts at moderate to high risk but who are not bleeding or at high risk of bleeding should be given either LMWH or UFH or fondaparinux.
Padua Score
Prevention of PE
1 Hospitalization with medical illness
Enoxaparin 40 mg SC qd orDalteparin 5000 units SC qd orFondaparinux 2.5 mg SC qd (in patients with a heparin allergy such as heparin-induced thrombocytopenia) orGraduated compression stockings or intermittent pneumatic compression
2 General surgery Unfractionated heparin 5000 units SC bid or tid orEnoxaparin 40 mg SC qd orDalteparin 2500 or 5000 units SC qd
3 Major orthopedic surgery
Warfarin (target INR 2 to 3) orEnoxaparin 30 mg SC bid orEnoxaparin 40 mg SC qd orDalteparin 2500 or 5000 units SC qd orFondaparinux 2.5 mg SC qdRivaroxaban 10 mg qd (in Canada and Europe)Dabigatran 220 mg bid (in Canada and Europe)
4 Oncologic surgery Enoxaparin 40 mg SC qd
5 Neurosurgery Unfractionated heparin 5000 units SC bid orEnoxaparin 40 mg SC qd andGraduated compression stockings or intermittent pneumatic compressionConsider surveillance lower extremity ultrasonography
6 Thoracic surgery Unfractionated heparin 5000 units SC tid andGraduated compression stockings or intermittent pneumatic compression
Prevention of PE
• For pts who are bleeding or at risk of bleeding use leg compression devices only.
• Pts are considered to be at high risk of bleeding if they meet any of the following criteria
• Active gastrodeodenal ulcer• Bleeding in 3 months prior to admission• Platelet count <50,000
Prevention of PE
Or if they had multiple risk factors for bleeding of lesser predictive strengthlike age >84 yrs,severe renal failure , hepatic failure with INR > 1.5 , male ,current cancer, ICU admission.
Prevention of PE
References Harrison -18 th edition
ACCP guidelines
Fishman's Pulmonary Diseases and Disorders
Crofton and Douglas's Respiratory Diseases (Wiley, 2000)