Trends in early reperfusion therapy in non-ST-elevation myocardial infarction patients treated with PCI

Background Current guidelines recommend an early (within 24h) invasive strategy after hospital admission for patients with non-ST-elevation myocardial infarction (NSTEMI) and an immediate invasive strategy (within 2h) for NSTEMI patients at very high risk. This study aimed to analyse the proportion of NSTEMI patients who underwent percutaneous coronary intervention (PCI) within 24h over time, examine their risk profiles, and assess in-hospital mortality. Methods We included all PCI-treated NSTEMI patients enrolled in the Swiss nationwide Acute Myocardial Infarction in Switzerland (AMIS) Plus registry between 2005 and 2024. Patients were grouped according to their door-to-balloon time: early (<24h) and delayed intervention (>=24h). Patient characteristics were compared descriptively and adjusted in-hospital mortality was analysed using logistic regression. In a subanalysis of patients with early PCI, we compared patients with immediate PCI (<2h) to those with PCI between 2 and 24h. Results From 9,364 patients, 7,825 (83.6%) received PCI within 24h. Patients with delayed PCI (16.4%) were older (median (IQR): 71 (61,79) vs. 65 (56,75) years; p<0.001), more often women (28% vs. 22%; p<0.001), had higher rates of comorbidities, defined as a Charlson comorbidity index (CCI)>1 (33% vs. 20%; p<0.001), but had less often a cardiac arrest prior to admission (1.5% vs. 4.8%; p<0.001). Overall, the proportion of delayed PCI dropped over time, albeit in a fluctuating manner (ptrend=0.042, Fig.1)). Overall, patients with delayed PCI had a lower crude in-hospital mortality than those treated early (1.8% vs. 2.8%, p=0.034). After adjustment for differences in admission year, age, sex, CCI>1, cardiac arrest prior admission, Killip class, heart rate and systolic blood pressure at admission, and creatinine, in-hospital mortality was similar in both groups (OR 0.79, 95%CI 0.47-1.26, p=0.332). Among the patients with early PCI, 1,824 patients (23.3% or 19.5% of the total population) had an immediate PCI. These patients were of similar age (median (IQR): 64 (56, 74) vs. 65 (56, 75); p=0.057), less often women (19% vs. 23%; p<0.001), had a much higher rate of cardiac arrest prior admission (15% vs. 1.6%; p<0.001) as well as Killip class 4 (8.1% vs. 1.2%; p<0.001), but a lower rate of CCI>1 (17% vs. 21%; p<0.001). Unadjusted in-hospital mortality was higher in immediately treated patients (6.6% vs. 1.5%; p<0.001) but this difference also disappeared after the above adjustments (OR 1.40, 95%CI 0.91-2.13, p=0.124). Conclusions Since 2005, the proportion of NSTEMI patients undergoing early PCI has increased, but no clear trend was visible over the last 10 years. Adjusted in-hospital mortality did not differ between patients with early and delayed PCI. Patients with immediate PCI had a much worse cardiac function at admission but after adjustment for these high-risk characteristics, in-hospital mortality was similar to patients receiving PCI within 2-24h.Predicted probabilities of delayed PCI