Abstract Body (Do not enter title and authors here): Background: Timely reperfusion with primary percutaneous coronary intervention (PCI) is critical for patients with ST-segment elevation myocardial infarction (STEMI). However, whether interhospital transfer delays impact clinical outcomes compared with direct admission remains uncertain.
Methods: We conducted a systematic review and meta-analysis of studies comparing interhospital transfer versus direct admission for primary PCI in STEMI patients. Searches were performed in PubMed, EMBASE, Scopus, and Web of Science. The primary outcome was in-hospital mortality. Secondary outcomes included post-discharge mortality (30 days, 6 months, 12 months), major adverse cardiovascular events (MACE), stroke, bleeding, target vessel revascularization, heart failure hospitalization, left ventricular ejection fraction (LVEF), and reperfusion time metrics.
Results: Sixteen studies (n = 165,084) were included, comprising ten retrospective cohorts and six prospective cohorts. In-hospital mortality was lower in the transfer group (RR, 0.82; 95% CI, 0.69–0.96) with absolute risk reduction is 7 fewer per 1000, while 6-month post-discharge mortality was lower in the direct admission group (RR, 1.34; 95% CI, 1.25–1.43) and the absolute risk is 14 more deaths per 1000 in the transfer group. No significant differences were found in MACE, stroke, bleeding, heart failure hospitalization, or total all-cause death. Transferred patients had a slightly lower LVEF (mean difference −1.57%; 95% CI, −2.58 to −0.57). Direct admission was associated with shorter symptom-to-balloon and total ischemic times, while door-to-balloon time was slightly shorter in transferred patients.
Conclusion: In STEMI patients treated with primary PCI, interhospital transfer was not associated with worse clinical outcomes despite longer delays to reperfusion. These findings highlight the critical role of coordinated STEMI networks in mitigating time-dependent risk and delivering equitable care across pathways.