Factors in Initial Anticoagulation Choice in Hospitalized Patients With Pulmonary Embolism.

Importance: Despite guideline recommendations to use low-molecular-weight heparins (LMWHs) or direct oral anticoagulants in the treatment of most patients with acute pulmonary embolism (PE), US-based studies have found increasing use of unfractionated heparin (UFH) in hospitalized patients. Objective: To identify barriers and facilitators of guideline-concordant anticoagulation in patients hospitalized with acute PE. Design, Setting, and Participants: This qualitative study conducted semistructured interviews from February 1 to June 3, 2024, that were recorded, transcribed, and analyzed in an iterative process using reflexive thematic analysis. Interview participants were physicians in emergency medicine, hospital medicine (hospitalist), interventional cardiology, and interventional radiology. Participants were recruited using maximum variation sampling targeting UFH-dominant vs LMWH-dominant approaches in hospitalized patients with acute PE. We triangulated results with a group of interventional cardiologists and radiologists (interventionalists). Main Outcomes and Measures: Common themes and factors associated with anticoagulant selection for hospitalized patients with acute PE. Reflexive thematic analysis was used to identify these themes and factors. Results: Of the 46 interviewees (median [IQR] age, 43 [36-50] years; 33 who identified as men [71.7%]), 25 (54.3%) were emergency physicians, 17 (37.0%) were hospitalists, and 4 (8.7%) were interventionalists. Each interview lasted a median (IQR) of 29 (25-32) minutes. Prominent themes associated with anticoagulant selection included agnosticism regarding choice of anticoagulant, the inertia of learned practice, and therapeutic momentum after anticoagulation initiation. Institutional culture and support were factors associated with choice of the dominant anticoagulation strategy. Additionally, factors associated with UFH use were fear of decompensation and misperceptions regarding the pharmacology of anticoagulants and catheter-directed treatments. Conclusions and Relevance: In this qualitative study, physicians across a spectrum of specialties and geographical settings reported common barriers and facilitators to the use of guideline-concordant anticoagulation in patients hospitalized with acute PE, particularly agnosticism regarding choice of anticoagulant, inertia of learned practice, therapeutic momentum after anticoagulation initiation, and institutional culture and support. Future implementation efforts may consider targeting these domains.