AHA/ACC Guideline Tackles Evidence-Based Acute PE Care

A joint clinical practice guideline from the American Heart Association (AHA) and the American College of Cardiology (ACC) in collaboration with eight other societies provides guidance to physicians and teams on the diagnosis, management, and follow-up of patients with acute pulmonary embolism (PE).

In the guideline, published online ahead of print in Circulation today, the committee outlines evidence-based diagnostic and treatment recommendations by care setting, provides guidance for applying seven validated PE-specific risk scores, and makes recommendations for triage, care unit placement within hospitals, and interhospital transfers.

Several  items are meant to help move the field forward and aid decision-making amid an array of US and European guidelines and swiftly moving science. Chief among these is the inclusion of more granularity in approaching risk stratification of patients with acute PE.

“For the last decade or more, we have been using the risk stratification scheme from the European Society of Cardiology, which essentially had four categories: low risk, intermediate-low, intermediate-high, and high risk,” Geoffrey Barnes, MD (University of Michigan, Ann Arbor), co-vice chair of the statement, told TCTMD.

The committee recognized that while patients may fall easily into a severity category like intermediate-high risk, they often have different phenotypes from other patients who fall into that category, he added. Therefore, better characterization can aid clinical decision-making, particularly around advanced interventions, as well as inform future research studies in the selection of patients.

As outlined in the guideline, the acute PE clinical categories range from A (subclinical) through E (cardiopulmonary failure). Within the symptomatic category B for those with low clinical severity score, patients may fall into subgroups of subsegmental (B1) or nonsubsegmental (B2). Symptomatic category C, for those with an elevated clinical severity score, carries the most differentiation. Within that category, patients may have normal right ventricle assessment and normal biomarkers (C1), abnormal right ventricle assessment or one or more abnormal biomarkers (C2), or abnormal right ventricle assessment and one or more abnormal biomarkers (C3). Category D is for those with incipient cardiopulmonary failure, which can include transient hypotension (D1) or normotensive shock (D2).

“For me as a clinician and as a researcher, what helps move this forward is separating out the group C—in particular the C3 group—from the D, because the D group is where we start to say, ‘Okay, now there’s really some underlying consequence of the acute PE, and it’s not just the RV enlargement or the troponin,” Barnes noted. “That’s where it’s going to be really important for clinicians to be able to say these are the patients for whom we need to be a lot more thoughtful about whether an acute intervention may offer them benefit or not.”

To further refine the classification, a respiratory modifier can be added to any subcategory or can be designated as its own subcategory in patients with prominent respiratory issues, including those needing supplemental oxygen or increased airflow.

Examples are given across these categories and the committee notes that patients may transition among categories as they are reassessed over time.

PERT and Follow-up Care Considerations

The guideline also gives consideration to multidisciplinary PE response teams (PERTs). The class 1 (level of evidence B-NR) recommendation indicates that there is moderate-quality evidence from one or more nonrandomized studies, observational studies, or registry studies supporting PERT assessment in patients who fall into categories C through E.

Barnes said while the writing committee felt that the evidence was strong enough to back implementation of PERT as a care model, it was careful to caution that there isn’t one right way to do it and that PERT team members are highly variable from institution to institution.

“Some may say, ‘We have a very active pulmonary critical care group that’s involved,’ and others might say, ‘We have a vascular medicine or cardiology group,’ so it’s going to look different in every hospital,” he said. Among the benefits the committee cites for building a PERT are improving risk stratification, expediting initiation of therapies like anticoagulation, and aiding the clinician in selecting the most appropriate advanced interventions for a given patient.

“What really drove the evidence was multiple studies showing patient-relevant benefits of a multidisciplinary care model,” Barnes noted. “We provided some guidance to highlight how it could be done but didn’t try to dictate [which specialties] should be in it.”

In the advanced management discussion, which covers recommendations for catheter-directed thrombolysis, mechanical thrombectomy, and surgical embolectomy, the committee notes that while a number of recent high-profile trials have delivered evidence in support of individual therapies, the evidence for patients at different stages of acute PE will continue to evolve and need to be reassessed.

Another area that Barnes and the committee think provides value for physicians is the section of the guideline devoted to patient aftercare considerations.

“Many people think of acute PE management as which anticoagulant to start in the emergency room and whether or not they need a procedure,” he added. “As a guideline writing committee, we felt like it was really important to think about the entire acute PE phase, not just in the hospital, but even those first several months when you get home.”

In addition to the timing of follow-up appointments, the recommendations highlight questions that patients might be asking regarding their psychological health after a PE diagnosis, how much activity is allowed, travel restrictions, and birth control and pregnancy counseling.

“We wanted to make sure we were providing as much guidance to clinicians as possible about what the evidence would say for a patient who’s going to have these questions and to prepare clinicians to address those so that patients get optimal care and hopefully have the best outcomes possible,” Barnes concluded.