#92: Pulmonary Embolism for the Internist

April 23, 2018 | By Matthew Watto, MD

Wow the crowd with your knowledge of pulmonary embolism! What are the red flags? What tools are available to guide you? How on Earth do you triage a patient with pulmonary embolism (PE)? What exactly is the RV spiral & how do PEs really cause morbidity and mortality?! Get schooled by pulmonary embolism expert, Dr. Oren Friedman, associate director of the Cardiac-Surgical Intensive care unit at the Cedars-Sinai Heart Institute. Doctors Cyrus Askin and Chris Chiu join as co-hosts.

Written by Cyrus Askin, MD, Justin Berk, MD, MBA, MPH. Figure by Cyrus Askin, MD. Edited by Matthew Watto, MD

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Test Yo’ Self Pulmonary embolism quiz

 

Clinical Pearls:

1. A deep vein thrombus (DVT) can “grow up” to become a pulmonary embolism (PE), but is part of the same spectrum of venous thromboembolism.
2. Pathophysiology: PE causes exponential increase in pulmonary vascular resistance. The thin-walled right ventricle (RV) fails. Left ventricle (LV) fails in sequence dropping cardiac output and leading to coronary ischemia of RV (even if no underlying stenosis).
3. Risk stratification: High if hypotension present. Low if minimal symptoms, and lack of RV strain on imaging. Intermediate-low if less severe RV dysfunction and patient looks well. Intermediate-high if more severe RV strain, increase RV:LV diameter, patient “looks ill”, high clot burden, or sPESI score = 1 or higher.
4. sPESI: age >80; h/o cancer, CHF, chronic lung disease; HR >110 bpm; systolic BP <100 mmHg; SaO2 <90%. Zero = low risk. One or above = high risk.
5. Treatment of low or intermediate-low risk patients: Anticoagulation with parenteral agent, vitamin K antagonist with a parenteral anticoagulant bridge, or a direct acting oral anticoagulant (DOAC).
6. Treatment of intermediate-high risk patients: Consider IV unfractionated heparin for easy on/off since these patients might need more advanced therapy if they become unstable or their symptoms fail to improve on anticoagulation. -Dr Friedman’s expert opinion.
7. Treatment of high risk PE (previously called “massive”) requires advanced therapies (see below).
8. Advanced therapies for PE: Systemic thrombolytics, catheter-directed thrombolytics, thrombectomy (either surgical or catheter directed).
9. IVC filters: Still controversial. Main indication is patient with DVT who cannot receive anticoagulation. Some experts place temporary filter if “large clot burden” and “low cardiopulmonary reserve”, but long term benefit has not been shown and future DVT risk increase [ add citation ]. Don’t forget to remove it!
10. When can I discharge my patient with PE? Patient is off oxygen, HR and BP are stable. Symptoms have improved and patient can tolerate ambulation. -Dr Friedman’s expert opinion.
11. How should I handle subsegmental PE? The evidence is not clear. Most patients still need treatment. Consider watchful waiting in patients without risk factors for VTE, who are hemodynamically stable with good RV function, no other clot burden and reliable follow up. -Dr Friedman’s expert opinion.

Credits

• Hosts: Matthew Watto MD, Stuart Brigham MD, Chris Chiu MD, Cyrus Askin MD
• Guest: Oren Friedman
• Written by: Cyrus Askin MD, Justin Berk, MD, MBA, MPH
• Figure by: Cyrus Askin MD