Type of presentation and predictors of early recurrence in patients with multiple acute coronary syndrome episodes. Insights from the AMIS Plus registry

Background Current literature lacks studies juxtaposing first and second acute coronary syndrome (ACS) episodes in patients with recurrent ACS. Methods ACS patients admitted to Swiss hospitals between 2004 and 2024 and enrolled for two ACS episodes in the Acute Myocardial Infarction in Switzerland (AMIS) Plus registry were included in this analysis. Patient characteristics at the first and second ACS episode were compared using descriptive statistics. Then, patients were categorised into two groups based on the time elapsed between first and second ACS episode (<1 year, ≥1 year). Finally, a multivariate logistic regression model was fitted to establish predictors of repeated ACS within one year versus after one year. Results A total of 870 patients and 1,740 ACS episodes were identified. While males (80.1%) were in median 60.5 (interquartile range [IQR] 51.7, 71.0) and 64.5 (IQR 55.8,74.5) years old at first and second ACS episode, respectively, the corresponding ages for females (19.9%) were 69.8 (IQR 58.2, 77.9) and 74.8 (IQR 63.2, 81.6) years. The median time between first and second event was 985 (IQR 295, 2255) days. The clinical presentation at the first event was almost evenly split between ST-elevation myocardial infarction (STEMI) and non-STEMI-ACS (NSTE-ACS; Figure). While in STEMI patients the second event was again almost evenly split between STEMI and NSTE-ACS, among patients presenting the first time with NSTE-ACS, the second event was a NSTE-ACS in almost ¾ of the patients (p<0.001; Figure). At second event, patients underwent percutaneous coronary intervention (PCI) less frequently (82.2% vs. 89.8%, p<0.001) and were less likely to go to rehabilitation (31.0% vs. 50.9%, p<0.001). Compared to patients in the ≥1 year group, patients in the <1 year group were older at first event (66.3 years vs. 60.7 years, p<0.001), had higher rates of diabetes (31.2% vs. 19.9%, p<0.001) and Charlson’s comorbidity index (CCI) >1 (26.3% vs. 12.4%, p<0.001). In terms of immediate therapy, patients in the <1 year group were less likely to receive PCI (78.7% vs. 94.0%, p<0.001), aspirin (94.6% vs. 98.9%, p<0.001), and P2Y12 inhibitors (95.7% vs. 98.6%, p=0.022). After adjusting for different covariates (age, sex, ACS type, Killip classification >2, arterial hypertension, diabetes, dyslipidemia, CCI >1, family history, and PCI), age (adjusted odds ratio, 1.02; 95% confidence interval, 1.00-1.03; p=0.039) and PCI (0.32; 0.18-0.57; p<0.001) were the only independent predictors of repeated ACS within one year. Conclusion Patients with two episodes of ACS were almost evenly split between STEMI and NSTE-ACS at the first presentation. While among STEMI patients the second ACS episode was again almost evenly split between STEMI and NSTE-ACS, patients presenting with NSTE-ACS the first time had a far higher probability of relapsing with a NSTE-ACS. Age and lower use of PCI were the only independent predictors of early as compared with late ACS recurrence.