Pulse Pressure and Outcomes After Out-of-Hospital Cardiac Arrest

Overview

STEP-PRESS is a predefined exploratory observational substudy nested within the STEPCARE trial. The study will evaluate whether early low pulse-pressure burden after out-of-hospital cardiac arrest is associated with early mortality and selected biomarker outcomes. Pulse pressure will be calculated as systolic blood pressure minus diastolic blood pressure using recorded STEPCARE blood-pressure values. The primary exposure is cumulative hours with pulse pressure below 40 mmHg during the first 12 hours after randomization. The primary outcome is all-cause mortality from the 12-hour landmark to day 7.

STEP-PRESS is a predefined exploratory observational substudy nested within STEPCARE, an international, multicenter, randomized factorial trial of intensive-care strategies after out-of-hospital cardiac arrest. STEPCARE is registered as NCT05564754. The STEPCARE biomarker substudy is registered as NCT06471972. STEP-PRESS will use data collected within the STEPCARE trial and applicable substudy approvals. No additional intervention, patient contact, or deviation from STEPCARE clinical management is planned for STEP-PRESS. The source population will consist of randomized STEPCARE participants, excluding consent withdrawals. Pulse pressure will be calculated as systolic blood pressure minus diastolic blood pressure using recorded STEPCARE blood-pressure values. The primary exposure is cumulative low pulse-pressure burden, defined as the number of hours during 0 to 12 hours after randomization in which interpolated pulse pressure is below 40 mmHg. The primary analysis population will be restricted to participants alive 12 hours after randomization, without mechanical circulatory support initiated before or within 24 hours after randomization, and with at least three valid recorded blood-pressure observations during 0 to 12 hours after randomization. The primary outcome is all-cause mortality from the 12-hour landmark to day 7. Key secondary outcomes include mortality in a 24-hour landmark analysis, neurological biomarker endpoints, 30-day mortality, 6-month survival, and 6-month functional outcome. Six-month poor functional outcome will follow the parent STEPCARE definition of modified Rankin Scale score 4 to 6. All STEP-PRESS objectives are associational. The substudy is not designed to test whether modifying pulse pressure improves outcomes.