Study protocol.

<div> Background Previous studies evaluating the influence of inter-hospital transfer on mortality in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI) reported conflicting results. The multicenter BRIGHT-4 trial demonstrated that bivalirudin plus a post-PCI high-dose infusion (1.75 mg/kg/h) reduced the 30-day primary endpoint of all-cause mortality or Bleeding Academic Research Consortium (BARC) types 3–5 bleeding compared with heparin monotherapy in STEMI patients. This study aimed to assess the impact of inter-hospital transfer on clinical outcomes and the effectiveness of bivalirudin versus heparin in STEMI patients undergoing PCI. Methods and findings In BRIGHT-4, 2,121 (35.7%) patients were transferred to a tertiary hospital for primary PCI while 3,817 (64.3%) were directly admitted to an interventional facility. The primary outcome was the composite of all-cause death or BARC types 3–5 bleeding occurring within 30 days. The secondary outcomes included stent thrombosis. Adjustments were made for baseline covariates and randomized treatments. Transferred patients had a longer median time from symptom onset to wire crossing the infarct-related artery (6.00 versus 3.93 hrs, <i><i>P</i></i> < 0.0001). At 30 days, there were no significant between-group differences in the rates of the primary outcome (4.2% versus 3.4%, adjusted hazard ratio [HR] 0.99, 95% confidence intervals [CI] 0.73, 1.33, <i><i>P</i></i> = 0.94) or its components. Bivalirudin with a high-dose post-PCI infusion was associated with consistent reductions of the primary outcome in the transfer (3.5% versus 4.8%, adjusted HR 0.66, 95%CI 0.42, 1.05) and direct admission (2.8% versus 4.1%, adjusted HR 0.62, 95% CI 0.43, 0.89) group compared with heparin monotherapy (<i><i>P</i></i>_interaction = 0.78), as well as individually for stent thrombosis. The main limitations of this study are that it is a <i><i>post hoc</i></i> analysis, and the long-term prognostic impact of transfer on STEMI patients requires further investigation. Conclusions In this <i><i>post hoc</i></i> analysis, 30-day clinical outcomes for STEMI patients transferred for PCI were not significantly worse than direct admission patients. Bivalirudin with a post-PCI high-dose infusion for 2–4 hrs was associated with lower rates of 30-day all-cause mortality, major bleeding and stent thrombosis, consistently observed in transfer and direct admission patients. Trial registration BRIGHT-4 trial <a href="http://www.clinicaltrials.gov/NCT03822975" target="_blank">NCT03822975</a> <a href="http://www.clinicaltrials.gov" target="_blank">http://www.clinicaltrials.gov</a> </div>