Association Between the Remnant Cholesterol Inflammation Index and Cardiac Syndrome X

Area of Science:

• Cardiology
• Vascular Biology
• Biomarker Discovery

Background:

• Cardiac Syndrome X (CSX) is part of the Ischaemia with Non-Obstructive Coronary Arteries (INOCA) spectrum, recognized as a systemic inflammatory vascular disorder.
• Remnant cholesterol (RC) and inflammation are key factors in residual cardiovascular risk, but their role in microvascular angina is not fully understood.

Purpose of the Study:

• To investigate the association between the Remnant Cholesterol Inflammation Index (RCII) and the clinical diagnosis of CSX.
• RCII integrates remnant cholesterol (RC) and high-sensitivity C-reactive protein (hs-CRP) to assess combined atherogenic and inflammatory burden.

Main Methods:

• A retrospective observational study of 392 patients undergoing coronary angiography.
• Patients were categorized into CSX (n=197) and control (n=195) groups.
• RCII was calculated (RC × hs-CRP); logistic regression and ROC curve analyses were used to evaluate its association with CSX.

Main Results:

• Patients with CSX had significantly higher levels of hs-CRP, SII, and RCII compared to controls (p < 0.001).
• RCII was independently associated with CSX (OR 1.095, p < 0.001) and showed significant diagnostic discrimination (AUC 0.765).
• RCII demonstrated superior diagnostic performance compared to RC, hs-CRP, or SII alone.

Conclusions:

• Elevated RCII levels are significantly associated with the clinical diagnosis of CSX.
• RCII may serve as a valuable composite biomarker for identifying residual inflammatory lipid risk in CSX.
• Further validation in prospective studies is warranted to confirm RCII's role in CSX management.