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

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.