Pulmonary embolism

Pulmonary embolism (PE) is a potentially life-threatening condition typically resulting from dislodged thrombus occluding the pulmonary arteries. Right heart failure and cardiac arrest may ensue if not aggressively treated. PE most commonly arises through embolization of deep vein thrombosis (DVT) of the legs, or less commonly from other locations in the body.

Patients who develop PE commonly have thromboembolic risk factors, such as cancer, trauma, major surgery, hospitalization, immobilization, pregnancy, or oral contraceptive use. PE may also be unprovoked (idiopathic), occurring in the absence of any identifiable extrinsic risk factors.

Symptoms include chest pain (especially with a deep breath), dyspnea, and a sense of apprehension. Hemoptysis and syncope are less common; the latter is strongly associated with increased clot burden. Some patients with PE will note symptoms of DVT, while others will not.

Assessment of pretest probability (using a validated score such as Wells or YEARS score) is key if PE is suspected, and should be used in combination with an algorithmic diagnostic approach to avoid unnecessary imaging when the likelihood of PE is low.

PE is definitively confirmed by an imaging study, most commonly computed tomography pulmonary angiogram (CTPA) or nuclear imaging such as planar V/Q or Q-SPECT CT.

Most patients with PE are successfully treated with anticoagulant therapy. Low-risk patients may be treated without hospitalization.

Hemodynamically unstable patients (those considered to have PE with a high risk for mortality) require urgent primary reperfusion in conjunction with anticoagulation and supportive care.

Generally, anticoagulant therapy for at least 3 months is required for patients with PE. Thereafter, continued anticoagulant therapy for secondary prevention is indicated in selected patients to reduce the risk of recurrent events.

Most cases of PE resolve. Possible long-term sequelae include ''post-PE syndrome”, chronic thromboembolic disease (CTED) and chronic thromboembolic pulmonary hypertension (where CTED is associated with pulmonary arterial hypertension and right heart abnormalities).

PE is a consequence of thrombus formation within a deep vein of the body (most frequently in the lower extremities) which embolizes to the lungs. Venous thromboembolic disease, or venous thromboembolism (VTE) is the preferred term to describe both deep vein thrombosis (DVT) and PE. Overall, approximately two thirds of VTE cases are isolated DVT, and one third are PE (with or without concomitantly diagnosed DVT). As concomitant disease may be asymptomatic, these figures may underestimate the frequency of overlapping disease manifestations.[1]Virani SS, Alonso A, Aparicio HJ, et al. Heart disease and stroke statistics-2021 update: a report from the American Heart Association. Circulation. 2021 Feb 23;143(8):e254-743. https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000000950 http://www.ncbi.nlm.nih.gov/pubmed/33501848?tool=bestpractice.com

This topic covers PE in adults.