Persistent inflammation after acute coronary syndrome identifies systemic vulnerability in a low inflammatory Japanese population: insights from the clinical deep data accumulation system (CLIDAS)

Background Residual inflammatory risk predicts adverse outcomes after percutaneous coronary intervention (PCI). While hs-CRP≧2.0mg/L defines residual risk in Western populations, its prognostic significance in the early post-acute coronary syndrome (ACS) phase remain uncertain in East Asians, who have lower baseline inflammation. Purpose To investigate the clinical impact of residual inflammatory risk after ACS in a low inflammatory Japanese population using the Clinical Deep Data Accumulation System (CLIDAS) registry. Methods We used the CLIDAS-PCI database integrating electronic medical records from 7 cardiovascular centers. We analyzed 1555 patients who underwent PCI between April 2014 and March 2019 and had hs-CRP measured at approximately 1 month and again within 4 months after index PCI. The primary endpoint was major adverse cardiac and cerebrovascular events plus (MACCE+), defined as a composite of cardiovascular death, non-fatal myocardial infarction, stroke, and heart failure hospitalization. Secondary endpoints included each component of MACCE+, target vessel revascularization and major bleeding. Patients were stratified into 4 groups based on an hs-CRP cutoff of ≧1.5 mg/L: persistently low, elevated, reduced, and persistently high (Figure 1A). Clinical outcomes were evaluated starting4 months after index PCI. Multivariable Cox models were adjusted for age, sex, hypertension, chronic kidney disease, diabetes, smoking, body mass index ≥25 kg/m2, prior PCI, lipid levels, and left anterior descending artery PCI lesion. Results In this cohort, the median age was 71 years and 77% were male. Median hs-CRP levels at 1 and 4 months were 2.0 and 0.8 mg/L. Median LDL cholesterol was 94 mg/dL, BMI 23.8 kg/m², and eGFR 62 mL/min/1.73m². Over 4 years, MACCE+ occurred in approximately 10% of the study population. Persistently high hs-CRP showed a higher risk for MACCE+ compared with persistently low hs-CRP (adjusted HR: 2.00, 95% CI: 1.34-2.99, P = 0.002, Figure 1B). Subgroup analysis showed that persistently high hs-CRP was associated with a higher risk of CV death, but not myocardial infarction or stroke. Persistently high hs-CRP was also associated with a higher risk of heart failure hospitalization and major bleeding, but not target vessel revascularization (Figure 1C). Conclusion In this low inflammatory Japanese population, persistent inflammation after ACS was associated with worse cardiovascular prognosis, particularly heart failure and bleeding events, but not with myocardial infarction, stroke, or target vessel revascularization. hs-CRP may reflect systemic vulnerability rather than thrombotic risk or chronic coronary progression. Given the lower baseline hs-CRP levels in East Asians, dynamic assessment using a lower cutoff (1.5 mg/L) may better identify residual inflammatory risk and stratify post-ACS prognosis in Japanese populations.