Authors' objectives: Developing and implementing interventions that change clinical practice can be challenging and complex. Such interventions can be particularly difficult when attempting to change established behaviours and practices. While extensive literature on implementation of interventions that focus on changing clinical practice exists, understanding of the difficulties involved in implementing interventions that go against accepted clinical practice is limited. To describe the challenges involved in delivering a complex intervention that goes against established clinical practice, using a clinical trial assessing the balance of benefits and risks of withholding anticoagulation for subsegmental pulmonary embolism as an example.

Authors' results and conclusions: Our findings indicated that factors such as clinician equipoise, discomfort with certain patient characteristics, and effective patient communication are closely connected and significantly impact both the process of changing clinical practice and the conduct of the trial. Clinicians faced difficulties in approaching eligible patients for trial participation, especially when a diagnosis and treatment plan had already been provided by another clinician. The tension between maintaining clinical equipoise and addressing the needs of unwell patients further complicated decisions, particularly when withholding anticoagulation in those with severe symptoms or multiple comorbidities. Communication about the risks and benefits of non-medication strategies for pulmonary embolism was also challenging, with concerns about undermining patient trust. Patients, on the other hand, expressed considerable anxiety about not receiving anticoagulants, with their perspectives on study participation and treatment heavily influenced by their prior health experiences and ongoing medical conditions. The active involvement of clinicians in the consent process had a positive effect on patients’ perceptions and experiences, with many feeling reassured in knowing they could contact clinical staff if needed. Our results highlight the multifaceted challenges when attempting to conduct studies that challenge accepted practices and norms. These complexities are deeply intertwined, influencing both clinical decision-making and patient recruitment for those studies.

Authors' methods: This study draws from a process evaluation conducted as part of a clinical trial. The evaluation utilised semistructured interviews with patients and clinicians during the trial’s internal pilot phase to investigate the acceptability of withholding anticoagulant medication and participants’ experiences within the trial. The data were analysed using the framework method. Eight patients with subsegmental pulmonary embolism (six females and two males) and three acute care clinicians (two males and one female) from five trial sites were interviewed. Small sample size of patients and clinicians across limited study sites; single method of data collection.

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hta/NIHR135833

Year Published: 2025

URL for published report: https://www.journalslibrary.nihr.ac.uk/hta/published-articles/PSDG7298

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: England, United Kingdom

DOI: 10.3310/PSDG7298

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk