The impact of off-hours presentation on outcome in patients with acute coronary syndrome complicated by cardiogenic shock

Introduction Cardiogenic shock (CS) remains the leading cause of death in patients with acute coronary syndrome (ACS) despite advances in medical therapy and revascularization strategies. Previous studies showed conflicting views on the off-hours effect on mortality, and limited data exist especially concerning ACS complicated by CS. Purpose This study aimed to evaluate the effect of on-hours versus off-hours presentation on the clinical outcomes in ACS patients with and without CS. Methods We retrospectively analyzed 2,425 consecutive ACS patients who underwent percutaneous coronary intervention (PCI) at our institution between January 2004 and December 2017. We divided patients in on-hours and off-hours groups and further stratified them by cardiogenic shock. The primary outcome was cardiovascular (CV) death up to 3-year, assessed by a 30-day landmark analysis. Results Among the 2,312 eligible ACS patients, 1,572 were admitted during on-hours and 740 during off-hours. The mean age was 68.5±12.0 years, 75.3 % were male, and ST-elevation myocardial infarction (STEMI) was observed in 75.3 % of cases. Notably, the 30-day CV mortality of off-hours group was significantly higher in ACS patients with CS (24.8 % vs 39.0 %, log-rank P = 0.0232) but not in those without CS(log rank P = 0.98). The CV mortality from 30 days to 3 years was comparable in both patients with and without CS. Multivariate Cox regression analysis showed off-hours presentation was significantly associated with higher risk of the 30-day CV mortality in ACS patients with CS (adjusted HR 1.65, 95%CI 1.16-3.16, log-rank P= 0.0110). Conclusions Off-hours presentation was significantly associated with higher risk of short-term CV death especially in ACS patients with cardiogenic shock. Further investigation and targeted efforts are necessary to improve the prognosis and off-hour medical care in high-risk patients.