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Pulmonary embolism

Case contributed by Dr David Carroll

Presentation

History of cirrhosis presenting with a tense, globose abdomen and 6 hours of rapidly worsening dyspnea. Hypotensive and tachycardic, 92% oxygen saturation on room air.

Patient Data

Age: 60 years
Gender: Female
Ultrasound

Point of care transthoracic echocardiography

Left ventricle is underfilled and hyperkinetic. Severe right ventricular dilation and hypokinesis with marked paradoxical septal motion. Increased RV wall thickness and apical trabeculation. Right ventricular outflow tract dilated with reduced systolic excursion. Suggestion of mid-systolic notching of the right ventricular outflow waveform with pulsed wave Doppler.

Marked right atrial dilation with leftward deviation of the interatrial septum. At least moderate tricuspid regurgitation. No intraluminal thrombi visible. No evidence of pericardial effusion. Inferior vena cava is distended with minimal respiratory variability suggestive of increased right-sided pressures. Large volume ascites appreciable. 

Overall suggestive of predominantly obstructive etiology to the acute circulatory failure.

CT

CTPA

Extensive bilateral, multilobar segmental and subsegmental filling defects suggestive of pulmonary emboli. Suggestion of right heart strain with an RV:LV ratio >1 and leftward deviation of the interventricular septum. Dependent atelectasis. Upper abdomen with extensive ascites. 

Case Discussion

The presence of right heart strain in an acutely dyspneic and hemodynamically unstable patient is suggestive of (albeit non-specific for) an acute pulmonary embolism. Echocardiographic signs of right heart strain include 5:

  • right ventricular dilation
    • an end-diastolic RV:LV diameter ratio > 1 defines severe
  • right ventricular systolic dysfunction
    • a pattern of right ventricular free wall hypokinesis with apical sparing is often found, referred to as the McConnell's Sign
  • paradoxical septal motion
    • an abrupt rise in pulmonary arterial pressures prolong right ventricular contraction
    • persistence of elevated RV pressures as the LV begins to relax results in reversal of the normal interventricular septal curvature
  • right atrial dilation
    • leftward bowing of the interatrial septum may be seen, as with the interventricular septum
  • tricuspid regurgitation
    • often secondary to annular dilation resulting in valvular incompetence
  • dilation of the inferior vena cava
    • with loss of its usual phasic variation throughout the respiratory cycle
    • a sonographic correlate of elevated right atrial/central venous pressures

Given the superior test characteristics of CT and VQ scanning, echocardiography is not considered a first-line diagnostic test for the exclusion of pulmonary embolism in the majority of patients. However, it remains useful in the critically ill and/or unstable patient due to its portability, speed, ability to assess for emergent diagnoses presenting in a similar manner (e.g. pericardial tamponade, tension pneumothorax, acute left ventricular failure), and lack of need for potentially nephrotoxic contrast use. Furthermore, in massive pulmonary embolism or peri-arrest situations which preclude further imaging, it may be used to empirically administer thrombolysis or anticoagulation 2

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Case information

rID: 83612
Published: 31st Oct 2020
Last edited: 31st Oct 2020
System: Cardiac, Vascular
Inclusion in quiz mode: Included
Institution: Ascension Healthcare

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