Five new risk-based categories of acute pulmonary embolism (PE) have been introduced to aid the evaluation and management of the condition in the first clinical practice guidelines from the American College of Cardiology and American Heart Association.

Patients in the first two categories (A and B) are asymptomatic or have mild symptoms and low risk of experiencing severe complications, and they often can be safely discharged from the emergency department.

Lead author Professor Mark A. Creager

Symptomatic patients with acute PE with elevated biomarkers and/or right ventricular dysfunction (Category C) or incipient cardiopulmonary failure (Category D) are at higher risk of adverse outcomes and require hospitalisation to to optimise treatment strategies. Similarly, hospitalisation is required for the most severe patients with cardiopulmonary failure characterised by persistent hypotension (Category E).

For evaluation of patients, the guideline details risk factors for acute PE, such as recent surgery or hospitalisation, trauma, prolonged immobility, pregnancy, obesity, cancer and blood clotting disorders. It also provides recommendations on use of D-dimer laboratory testing and computed tomography pulmonary angiography to diagnose acute PE.

Management of acute PE is also based on the new risk categories, with oral anticoagulation with DOACs recommended over warfarin, and low-molecular-weight heparin recommended over unfractionated heparin in patients with acute PE who require initial parenteral anticoagulant therapy..

In patients with a first acute PE without a major reversible risk factor and in those with a persistent risk factor, continuing anticoagulation beyond the initial treatment phase (3-6 months) into the extended phase is recommended.

The five A-E categories also include sub-classifications that can help guide management of acute PE. For example, Category D1 identifies patients with transient or recurrent hypotension that is short-lived or responds to volume expansion and is not accompanied by any signs of reduced perfusion or end-organ dysfunction. Category D2 requires a marker of decreased perfusion or end-organ dysfunction.

The guidelines recommend advanced therapies such as systemic thrombolysis, catheter-based thrombolysis, mechanical thrombectomy, and surgical embolectomy are for patients with acute PE in Category D1-2.

There is also a recommendation for PE response teams to improve timeliness of care.

In monitoring and follow up, patients who have had acute PE should be asked about PE-related symptoms and functional limitations at every visit for at least one year to screen for chronic thromboembolic pulmonary disease or other causes of dyspnea and functional limitation.

The guideline authors said the five new categories replaced three risk classifications (low risk, submassive, and massive PE) in a 2011 AHA scientific statement. The wider wider range reflected recent evidence of heterogeneity in outcomes within risk categories, and the need to recognise presentations dominated by respiratory rather than hemodynamic compromise.

“There have been significant advances in the understanding of pulmonary embolism and treatments to effectively manage this condition,” said lead author Professor Mark A. Creager, a professor of medicine at the Geisel School of Medicine at Dartmouth College in Hanover New Hampshire.

“We anticipate that decisions guided by these recommendations will result in more rapid diagnosis and application of effective, evidence-based treatments, leading to better outcomes, such as decreased risk of death and disability, for people with acute pulmonary embolism,” Professor Creager said.

The guidelines are published in Circulation (link here).