Combined diagnostic value of the systemic immune-inflammation index and LDL for coronary microvascular disease: a retrospective cohort study.

BACKGROUND

Coronary microvascular disease (CMVD) is an important contributor to ischemic heart disease. Symptomatic patients without obstructive coronary lesions may still have microvascular ischemia, which is associated with an increased risk of major adverse cardiovascular events. The diagnosis of CMVD relies on coronary function testing or noninvasive imaging techniques, which are not universally available and may limit routine clinical implementation.

OBJECTIVES

Growing evidence supports the notion that biological processes such as inflammation and oxidative stress drive vascular aging and contribute to microvascular dysfunction. The systemic immune-inflammation index (SII) is a marker used to assess immune-inflammatory and thrombotic status and has shown prognostic value in chronic heart failure, and acute myocardial infarction. However, its role in CMVD remains underexplored.

DESIGN

To address this gap, we retrospectively analyzed 180 patients with angina who underwent myocardial contrast stress echocardiography between January and November 2022 at the First Affiliated Hospital of Harbin Medical University.

METHODS

Based on coronary microcirculatory function, patients were divided into two groups: 91 with normal function and 89 with microcirculatory disorders. Clinical data and lab indicators were compared.

RESULTS

SII was significantly higher in the CMVD group (722.96 ± 354.10 vs 618.51 ± 324.50; p < 0.05). Logistic regression identified SII, LDL cholesterol as independent CMVD predictors. Pearson correlation demonstrated an inverse relationship between SII and coronary flow reserve, supporting its link with impaired microvascular function. Receiver operating characteristic analysis further showed that the combined SII and LDL model provided improved discriminatory performance compared with either marker alone, achieving an area under the curve of 0.76 with a sensitivity of 77.5% and specificity of 69.2%.

CONCLUSION

SII is independently associated with CMVD and improved discriminatory performance when combined with LDL.