Pulmonary Embolism (PE) Overview

Pulmonary Embolism (PE) is a serious medical emergency with an annual incidence of approximately 60 to 120 cases per 100,000 people in North America and Europe. Most patients are diagnosed with PE in the Emergency Department (ED), and hospitalization is required for the majority of U.S. patients. Anticoagulation is the cornerstone of PE treatment, including unfractionated heparin (UFH), low-molecular-weight heparins (LMWH), and direct oral anticoagulants (DOACs). Although professional guidelines recommend using LMWH or DOACs as the initial anticoagulation treatment for acute PE, recent U.S. studies have shown an increasing use of UFH among hospitalized patients. While equivalent in efficacy to LMWH and DOACs, UFH has complex pharmacokinetics, requires frequent monitoring, and poses a higher bleeding risk. Thus, this study aims to explore the barriers and facilitators influencing initial anticoagulation decisions in hospitalized PE patients, aiming to foster better implementation of guideline-recommended strategies.

Paper Sources and Author Information

This paper was authored by William B. Stubblefield, MD, MPH, Ron Helderman, MD, Natalie Stokes, DO, MPH, MS, Colin F. Greineder, MD, PhD, Geoffrey D. Barnes, MD, MSc, David R. Vinson, MD, and Lauren M. Westafer, DO, MPH, MS. The authors are affiliated with esteemed institutions such as Vanderbilt University Medical Center, University of Texas Southwestern Medical Center, University of Massachusetts Chan Medical School-Baystate, University of Michigan, and others. The paper was published on January 3, 2025, in the JAMA Network Open, DOI: 10.1001/jamanetworkopen.2024.52877.

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Study Methods and Processes

Research Design

This study utilized semi-structured interviews as part of a qualitative research framework, targeting emergency medicine and hospital medicine physicians in the U.S. The research team developed interview guides, piloted these among three emergency physicians, and iteratively updated them based on feedback. The questions were structured using two implementation science frameworks: the Consolidated Framework for Implementation Research (CFIR) and the Theoretical Domains Framework (TDF). CFIR facilitates systematic assessment of barriers and facilitators, while TDF focuses on individual-level behavior changes. This study adhered to qualitative research reporting standards (COREQ checklist) and was approved by the Baystate Medical Center Ethics Committee.

Study Population and Data Collection

The study employed a maximum variation sampling strategy, designed to capture insights from physicians favoring either UFH-dominant or LMWH-dominant approaches. Participants included emergency medicine physicians, hospitalists, as well as interventional cardiologists and radiologists. Interviews were conducted via videoconferencing software (Zoom), lasting approximately 30 minutes each. Audio recordings were transcribed for qualitative analysis. Demographic data such as age, gender, race, years of practice, location, and practice type were also collected.

Data Analysis

Transcriptions were anonymized and coded using qualitative analysis software (Dedoose). Reflexive thematic analysis was applied, alternating between inductive and deductive methods. Five team members independently reviewed transcripts and developed a shared coding framework through discussion. Themes identified were mapped to the CFIR and TDF frameworks.

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Key Findings

Indifference to Anticoagulant Choice

Many participants expressed a lack of preference between UFH and LMWH, viewing both drugs as similar in efficacy and safety. This indifference was often attributed to institutional culture or the inertia of learned practice, rather than any strong convictions about drug characteristics. Both emergency physicians and hospitalists often deferred decision-making responsibility to each other or to consultants, which, in turn, contributed to the frequent use of UFH.

Therapeutic Momentum

Therapeutic momentum—defined as the reluctance to alter an existing course of treatment—played a significant role. Emergency physicians tended to choose UFH to maintain flexibility for subsequent care teams, but hospitalists rarely switched from UFH to other anticoagulants (e.g., LMWH or DOACs) except at the time of discharge. Decisions were driven by convenience, timing of transitions, and a desire to minimize the number of anticoagulation changes.

Institutional Culture and Support

Institutional culture heavily influenced anticoagulant selection. Despite the absence of formal institutional guidelines, many physicians selected anticoagulants based on organizational norms or perceived preferences of inpatient or consulting teams. Some participants associated the presence of a PE response team (PERT) or catheter-directed treatment capacity with UFH use, even when such circumstances were not directly applicable.

Misunderstandings About UFH

UFH’s popularity stemmed partly from misconceptions about its pharmacology. For instance, it was believed to act faster and be more potent compared to alternatives, particularly in cases of perceived high clot burden or potential decompensation. However, deeper discussions during interviews revealed participants’ realization that LMWH often achieves therapeutic levels more rapidly.

Misunderstandings About Role in Catheter-Directed Treatment

Most emergency and hospital medicine physicians believed anticoagulation needed to be stopped or reversed for catheter-directed treatments, spurring UFH use to preserve flexibility. Conversely, interventionalists clarified that LMWH use did not contraindicate catheter-directed interventions.

Higher Resource Demand for UFH

While UFH was perceived as administratively easier for physicians, many later recognized its higher resource demands for nursing staff and patients, including frequent lab draws and dosing adjustments. Such factors contributed to its lower favorability in LMWH-dominant institutions.

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Conclusion and Significance

The study found that both emergency and hospital medicine physicians demonstrated substantial indifference toward anticoagulant choice in acute PE treatment, rooted in learned practices, therapeutic momentum, and institutional culture. Misunderstandings about UFH and fear of complications were key factors driving UFH use, whereas awareness of its resource intensity correlated with LMWH-dominant choices. These findings highlight actionable areas for improving the adoption of guideline-recommended anticoagulation strategies.

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Study Highlights

1. Key Insights: The study revealed major barriers and facilitators influencing anticoagulant choice in acute PE, notably misconceptions about UFH and therapeutic inertia.
2. Innovative Approach: By leveraging reflexive thematic analysis alongside CFIR and TDF frameworks, the study offers a structured understanding of decision-making dynamics.
3. Practical Impact: Results provide actionable recommendations for implementing evidence-based anticoagulation strategies across emergency and hospital settings.

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Supplemental Insights

The study has limitations, including a narrow focus on U.S.-based physicians and the inherent subjectivity of qualitative research. Nonetheless, the use of maximum variation sampling captured diverse perspectives across institutions and geographies, offering vital insights for future implementation strategies aimed at improving the quality and value of PE management.