Supplementary Material for: Implementing low-intensity thrombolysis monitoring for patients with acute ischemic stroke in Latin America: insights from the OPTIMISTmain process evaluation

Introduction: The Optimal Post rtPA-IV Monitoring in Ischemic Stroke Trial (OPTIMISTmain) was an international, pragmatic, stepped-wedge, cluster- randomized, non-inferiority trial designed to compare a low-intensity protocol to standard high-intensity monitoring in patients with mild-to-moderate acute ischemic stroke treated with thrombolysis. The results showed safety, feasibility and non-inferiority efficacy of the low-intensity monitoring protocol supporting hospitals to consider adopting this approach in stroke care depending on local resources and circumstances. An embedded process evaluation was undertaken to explore factors influencing implementation and impact of the intervention in Latin America.

Methods: A convergent mixed-methods design was used to combine quantitative data and qualitative interviews with implementers and patients (or family members) as participating hospitals in Chile and Mexico. Purposive sampling ensured that a diverse range of experiences and discourses were captured, and normalization process theory (NPT) guided the identification of factors facilitating or hindering the incorporation of low-intensity monitoring. The analysis focused on key implementation outcomes.

Results: Low-intensity monitoring was widely accepted by clinicians who found it efficient, straightforward to implement, and potentially cost-saving for hospital services. Patients and families expressed acceptance, emphasizing the protocol´s potential to support continuous improvements in healthcare. Implementation challenges included staff turnover across shifts and hospital units, reliance on external contractors, and resistance to changing established care routines. Factors enabling successful implementation included strong team communication, dedicated stroke units, and ongoing feedback. Overall, the intervention demonstrated high acceptability, adoption and appropriateness, fidelity (median of 17 assessments in both countries), and sustainability. Feasibility outcomes were more variable, reflecting organizational challenges at the healthcare system level, such as for example initial resistance of nursing teams and high workloads in emergency services.

Conclusions: Implementation of a novel low-intensity monitoring protocol was well accepted by healthcare staff and offers potential benefits to patients with mild-to-moderate acute ischemic stroke admitted to hospitals in Latin America. Embedding a process evaluation into the main trial provided valuable insights into the challenges of implementing a complex intervention. A comprehensive understanding of the factors influencing organization change is critical to improving health outcomes.