Novel cardiometabolic indices and coronary microvascular dysfunction in intermediate stenosis: the role of AIP and TyG index

Background This study assessed the association between two emerging cardiometabolic indices—the atherogenic index of plasma (AIP) and triglyceride-glucose (TyG) index—and coronary microcirculation in patients with intermediate stenosis. Methods This cross-sectional study included 566 consecutive patients with intermediate coronary stenosis treated at China-Japan Friendship Hospital between January 2023 and February 2024. Coronary microvascular dysfunction (CMD) was defined as an angiography-derived index of microcirculatory resistance (AMR) of ≥ 2.5. The AIP and TyG index were calculated from baseline laboratory data. All participants were categorized into tertiles based on each index. Results A total of 407 patients (71.9%) were diagnosed with CMD. Restricted cubic spline analysis showed a linear association of both AIP and the TyG index with CMD. Multivariate logistic regression revealed that individuals in the highest tertile of each index had a significantly greater odds of CMD than those in the lowest tertile (AIP: odds ratio (OR) = 2.00, 95% confidence interval (CI) = 1.21–3.31, P = 0.007; TyG index: OR = 2.11, 95% CI = 1.26–3.53, P = 0.005). Subgroup analyses reveal a more pronounced relationship between AIP and CMD in the nonhypertensive subgroup ( P for interaction = 0.004). Receiver operating characteristic curve analysis showed comparable discriminatory ability between AIP and TyG index (the area under the curve: 0.567 vs. 0.559, DeLong test, P = 0.62). Conclusion In patients with intermediate coronary stenosis, elevated AIP and TyG index were positively associated with CMD. Both indices may serve as potential adjunctive biomarkers for CMD in this population.