The relationship between peak serum creatine kinase levels after PCI and long-term outcomes in patients with STEMI: a report from the STELA registry

Abstract Background The maximum serum creatine kinase (CK) level after primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) has been recognized as an independent prognostic factor for 1-year mortality and left ventricular (LV) function. However, this evidence is based on studies conducted during the era of bare-metal stents, and it remains unclear whether this holds true in the current era dominated by second-generation drug-eluting stents (DES). Objective To evaluate the relationship between maximum CK levels after primary PCI and prognosis in the current era where second-generation DES are the standard of care. Methods This study is a sub-analysis of the STELA registry, a multicenter registry study. The STELA registry included STEMI patients who underwent primary PCI within 24 hours of symptom onset at 12 Japanese institutions capable of performing PCI 24/7, with data collected between 2015 and 2019. The area under the curve (AUC) was calculated for in-hospital mortality and maximum CK levels, and a cutoff value was determined to divide patients into two groups. All-cause mortality and LV function were analyzed. Additionally, multivariable Cox regression analysis was performed to assess the independence of the CK cutoff value as a prognostic factor for all-cause mortality. Results A total of 2,059 STEMI patients were included, with a median follow-up period of 2.2 1.1–3.9 years. The in-hospital mortality rate was 7.1%, and the overall all-cause mortality rate during the observation period was 12.3%. The cutoff value for maximum CK levels associated with in-hospital mortality was 7098 U/L (AUC: 0.70). Patients with maximum CK levels 7098 U/L were younger, predominantly male, had higher BMI, and a higher proportion of Killip class IV compared to those with lower CK levels. Angiographic findings showed a higher prevalence of culprit lesions in the proximal left anterior descending artery, as well as significantly more cases with pre-procedural TIMI flow grade 0 and thrombus TIMI grade 5. The proportion of stenting was similar between the two groups (93% vs. 90%, P=0.26), but the use of mechanical circulatory support was significantly higher in the CK 7098 U/L group (21% vs. 12%, P0.001). Procedural complications, such as the no-reflow phenomenon, were also significantly more frequent. Patients with CK 7098 U/L had significantly worse outcomes for all-cause mortality (HR: 4.10; CI: 3.19–5.27) and reduced LV function (44±9.8 vs. 56±10.6, P0.001). Multivariable analysis confirmed that CK 7098 U/L was an independent prognostic factor for all-cause mortality (HR: 3.50; CI: 2.31–5.31). Conclusion In the current era dominated by second-generation DES, maximum CK levels after primary PCI remain predictive of all-cause mortality and LV function, serving as an independent prognostic factor for long-term outcomes.