Process Evaluation of an Ambulance-Delivered Early Intensive Blood Pressure-Lowering Stroke Trial: Design, Rationale, and Reflection

Ruixue Liu; Chen Chen; Feifeng Liu; Yapeng Lin; Hongling Chu; Hueiming Liu; Craig S Anderson; Jie Yang; Gang Li; Lili Song; Menglu Ouyang

doi:10.1159/000541322

Process Evaluation of an Ambulance-Delivered Early Intensive Blood Pressure-Lowering Stroke Trial: Design, Rationale, and Reflection

Cerebrovasc Dis. 2024 Sep 5:1-7. doi: 10.1159/000541322. Online ahead of print.

Authors

Ruixue Liu¹, Chen Chen^{2

3

4}, Feifeng Liu², Yapeng Lin^{5

6}, Hongling Chu⁷, Hueiming Liu³, Craig S Anderson^{3

4}, Jie Yang^{8

9}, Gang Li², Lili Song^{3

4}, Menglu Ouyang^{3

4}

Affiliations

¹ International Clinical Research Center, Chengdu Medical College, Chengdu, China, wdcliuruixue@163.com.
² Department of Neurology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China.
³ Faculty of Medicine, The George Institute for Global Health, UNSW, Sydney, New South Wales, Australia.
⁴ The George Institute for Global Health, Beijing, China.
⁵ International Clinical Research Center, Chengdu Medical College, Chengdu, China.
⁶ Department of Neurology, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, China.
⁷ Research Center of Clinical Epidemiology, Peking University Third Hospital, Beijing, China.
⁸ Department of Neurology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.
⁹ Sichuan Provincial Key Laboratory for Human Disease Gene Study, Chengdu, China.

PMID: 39236681
DOI: 10.1159/000541322

Abstract

Introduction: The fourth INTEnsive ambulance-delivered blood pressure Reduction in hyper-ACute stroke Trial (INTERACT4) is a large-scale, multicenter, prospective, randomized, open-label, blinded endpoint assessment trial, initiated in an ambulance in China, aiming at evaluating the effectiveness and safety of prehospital blood pressure (BP) lowering in patients with suspected acute stroke and elevated BP. A prespecified process evaluation is intended to explore the implementation of the trial intervention, provide support to interpret the trial outcomes and put forward suggestions to scale up the intervention in broader settings in the future.

Methods: This process evaluation is a mixed-methods design, and follows the Normalization Process Theory (NPT) and the UK Medical Research Council (UK MRC) guidance. Fidelity, reach, acceptability, appropriateness, adoption, sustainability, and relevant contextual factors and mechanisms affecting the implementation of prehospital early intensive BP-lowering treatment will be analyzed. Semi-structured interviews with ambulance staff, ward and emergency department clinicians, and nurses are undertaken to explore perceptions of the intervention, contextual factors, and potential suggestions for future implementation in practice. Data from observational records, surveys, conventional monitoring data, on-site records, and case report forms will be analyzed to understand background care and context.

Conclusion: The process evaluation of INTERACT4 will provide insights for the implementation of prehospital early intensive BP-lowering intervention in different health systems and help better explain the trial results for further scale up.

Keywords: Clinical trial; Emergency; Implementation science; Intensive BP lowering; Process evaluation; Stroke.