Transfer-workflow optimization in a regional chest pain center network reduces door-in–door-out time in ST-segment elevation myocardial infarction: An interrupted time-series study with spectral validation

Background Inter-hospital transfer delays remain a major barrier to timely primary percutaneous coronary intervention (PCI) for patients with ST-segment elevation myocardial infarction (STEMI). We evaluated a structured transfer-workflow optimization program in a regional hub-and-spoke chest pain center network. Methods This retrospective interrupted time series study included 785 transferred STEMI patients recorded in the National Chest Pain Center Reporting Platform within the Hanzhong Central Hospital regional network, China, from November 2019 to September 2025. A hub-led workflow intervention began in February 2022 and targeted reception, triage, STEMI recognition, internal pathways, and earlier hub notification at spoke hospitals. The primary endpoint was monthly mean door-in–door-out (DIDO) time; secondary endpoints were first medical contact–to–wire crossing (FMC2W) and in-hospital outcomes. Segmented regression was complemented by autocorrelation diagnostics, sensitivity models, spectral analyses, and negative-control analyses. Results The intervention was associated with an immediate DIDO reduction of 49.7 min ( P = 0.009), with consistent autocorrelation-robust estimates. Shorter DIDO was associated with shorter FMC2W, whereas non-targeted downstream intervals remained stable. Spectral analyses supported reduced high-frequency variability. Crude rates of composite complications and new-onset in-hospital heart failure were lower after intervention, but model-based effects at 12 and 24 months were not significant. These were fitted-model estimates, not patient-level follow-up; clinical endpoints were exploratory. Conclusions Structured transfer-workflow optimization was associated with reduced DIDO time and shorter FMC2W. Clinical outcome findings were exploratory and did not establish long-term benefit.