ACUTE PULMONARY EMBOLISM Part I

ACUTE PULMONARY EMBOLISMPart I

Etiology,Clinical features,DiagnosisDr Vinod G V

• PE and DVT are two clinical presentations of venous thromboembolism (VTE) and share the same predisposing factors.

• Most cases of PE occurs as a consequence of DVT

• Acute case fatality rate for PE ranges from 7 to 11%

N=94194; 6 yr follow up.The incidence rate for • All first VT events was 1.43 per 1000 person-years [95%

confidence interval (CI): 1.33–1.54]

• Deep-vein thrombosis (DVT) was 0.93 per 1000 person-years (95% CI: 0.85–1.02)

• Pulmonary embolism (PE) was 0.50 per 1000 person-years

(95%CI: 0.44–0.56).

J Thromb Haemost 2007; 5: 692–9.

Acquired factors

• Reduced mobility• Advanced age• Cancer• Acute medical illness• Major surgery• Trauma• Spinal cord injury• Pregnancy and

postpartum period

• Polycythemia vera• Antiphospholipid antibody

syndrome• Oral contraceptives• Hormone-replacement

therapy• Heparins• Chemotherapy• Obesity• Central venous

catheterization• Immobilizer or cast

Hypercoagulable states • Factor V Leiden resulting in activated protein C resistance• Prothrombin gene mutation • Antithrombin deficiency• Protein C deficiency• Protein S deficiency

• First thrombosis usually at young age (<40 yr)• Frequent recurrences• Family history of VTE

Pathophysiology

Clinical features

Symptoms• unexplained dyspnea• Chest pain, either pleuritic

or “atypical”• Cough• Haemoptysis

Signs• Tachypnea• Tachycardia• Low-grade fever• Left parasternal lift• Tricuspid regurgitant murmur• Accentuated P2• Hypotension

Clinical classificationMassive PE: • Systolic blood pressure <90 mm Hg • Poor tissue perfusion or • Multisystem organ failure plus • Right or left main pulmonary artery thrombus or “high clot burden”

Submassive PE:• Hemodynamically stable but moderate or severe right ventricular

dysfunction or enlargement

Small to moderate PE: • Normal hemodynamics and normal right ventricular size and function

Classic Well’s criteria

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

ECG

• Sinus tachycardia• Incomplete or complete right bundle branch

block• Right-axis deviation• T wave inversions in leads III and aVF or in leads

V1-V4• S wave in lead I and a Q wave and T wave

inversion in lead III (S1Q3T3) • Atrial fibrillation or atrial flutter

CHEST X RAY• Major chest radiographic abnormalities are uncommon.

• A near-normal radiograph in the setting of severe respiratory compromise is highly suggestive of massive PE.

• Focal oligemia (Westermark sign) indicates massive central embolic occlusion.

• A peripheral wedge-shaped density above the diaphragm (Hampton hump) usually indicates pulmonary infarction.

• Enlargement of the descending right pulmonary artery. The vessel often tapers rapidly after the enlarged portion

ECHO• Right ventricular enlargement or hypokinesis, especially free wall

hypokinesis, with sparing of the apex (the McConnell sign) • Interventricular septal flattening and paradoxical motion toward the left

ventricle, resulting in a D-shaped left ventricle in cross section• Tricuspid regurgitation• Pulmonary hypertension with a tricuspid regurgitant jet velocity >2.6

m/sec• Loss of respiratory-phasic collapse of the inferior vena cava with

inspiration• Dilated inferior vena cava without physiologic inspiratory collapse• Direct visualization of thrombus (more likely with transesophageal

echocardiography)

Computed Tomography

• Most commom investigation performed• SDCT or MDCT • MDCT more sensitive for subsegmental level

thrombi• CT can rule out other causes

CT

• Two clinical studies reported a sensitivity around 70% and a specificity of 90% for single-detector CT (SDCT).

• Negative SDCT and the absence of a proximal DVT

on lower limb venous ultrasonography in non- high clinical probability patients was associated with a 3-month thromboembolic risk of approximately 1%

• For MDCT a sensitivity of 83% and a specificity of 96% .• In patients with a low or intermediate clinical probability

of PE as assessed by the Wells score, a negative CT had a high NPV for PE (96 and 89%respectively) and only 60% in those with a high pretest probability.

• The PPV of a positive CT was high (92–96%) in patients with an intermediate or high clinical probability but

much lower (58%) in patients with a low pretest likelihood of PE

D-Dimer Assay

• Endogenous fibrinolysis• More sensitive but less specific• Negative predictive value• Not very useful in hospitalized patients since

values may be elevated due to comorbid illness

• D-dimer ELISA is an excellent screening test for suspected PE

• A negative D-Dimer assay in low clinical probability case rules out PE

• D-dimer ELISA was often elevated in the absence of PE like sepsis,cancer,acute medical illness

• Low specificity and poor positive predictive value

Trop I

• Elevated levels indicates RV dialatation or RV dysfunction

• Helps to identify patients with massive pulmonary embolism

• Has prognostic value

Pulmonary Angiography

• Invasive procedure• Considered previously as gold standard • Now rarely performed as a diagnostic

procedure• Direct evidence of thrombus seen as filling

defect or amputation of an arterial branch.

Lung V/Q Scan

• Not performed routinely• In patients with elevated D Dimer and

contraindication for CT contrast allergy;renal failure

• Shows multiple perfusion defects in massive pulmonary embolism

Venous Ultrasonography

• Evidence of DVT in lower limbs• Loss of vein compressibility• 50% of patients with PE has no evidence of

DVT

SUMMARY

• High clinical suspicion is needed for diagnosis• No symptoms , signs or test is highly specific

for PE• Assess pretest clinical probability before

applying diagnostic test• Integrated diagnostic approach is needed

.Most common cause of inherited thrombophiliaA.Factor V LeidenB.Prothrombin gene mutationC.protein c defficiencyD.protein s defficiency

2. Most common ECG finding seen in patients with acue pulmonary embolismA.Sinus tachycardiaB.S1Q3T3C.T inversion in precordial leadsD.RBBB

Well’s score includes all exceptA.Cancer treated within 6 months B.HaemoptysisC.Surgery within 4 wksD.Dyspnoea

D Dimer assay in acute pulmonary embolism ;wrong statementA.specificity is low B.High NPV in low probability casesC.Values >500ng/ml diagnostic of PED.Most useful in emergency department than in hospitalised patients

Most common symptom in PEA.Pleuritic chest painB.HaemoptysisC.Sudden onset dyspnoeaD.Syncope

Most common clinical sign in PEA.TachypnoeaB.RV S3C.Elevated JVPD.Pleural rub

False statement about ECHO IN PEA.Mc connell’s sign most sensitive signB.RV dilatation indicates poor prognosisC.D shaped LV D.TEE more sensitve for demonstrating

thrombus