Safety of early hospital discharge following admission with ST-elevation myocardial infarction treated with percutaneous coronary intervention: a nationwide cohort study

Background: The Second Primary Angioplasty in Myocardial Infarction (PAMI-II) risk score is recom-mended by guidelines to identify low-risk patients with ST-elevation myocardial infarction (STEMI) for an early discharge strategy. Aims: We aimed to assess the safety of early discharge (<2 days) for low-risk STEMI patients treated with primary percutaneous coronary intervention (PCI). Methods: Using nationwide data from the SWEDEHEART registry, we identified patients with STEMI treated with primary PCI during the period 2009-2017, of whom 8,092 (26.4%) were identified as low risk with the PAMI-II score. Low-risk patients were stratified according to their length of hospital stay (<= 2 days vs >2 days). The primary endpoint was major adverse cardiovascular events (MACE, including death, reinfarction treated with PCI, stroke or heart failure hospitalisation) at one year, assessed using a Cox proportional hazards model with propensity score as well as an inverse probability weighting propensity score of average treatment effect to adjust for confounders. Results: A total of 1,449 (17.9%) patients were discharged <= 2 days from admission. After adjustment, the one-year MACE rate was not higher for patients discharged at >2 days from admission than for patients discharged <= 2 days (4.3% vs 3.2%; adjusted HR 1.31, 95% confidence interval [CI]: 0.92-1.87, p=0.14), and no difference was observed regarding any of the individual components of the main outcome. Results were consistent across all subgroups with no difference in MACE between early and late discharge patients. Conclusions: Nationwide observational data suggest that early discharge of low-risk patients with STEMI treated with PCI is not associated with an increase in one-year MACE.