[Metabolic associated fatty liver disease and myocardial ischemia in non-obese patients suspected of coronary artery disease].

Objective: To explore the association between metabolic dysfunction-associated fatty liver disease (MAFLD) and myocardial ischemia in non-obese patients with suspected coronary heart disease (CAD), and to analyze the differences in this association across subgroups stratified by body mass index (BMI) and coronary artery lesion severity. Methods: This retrospective study enrolled non-obese patients (18.5 kg/m²≤BMI<28.0 kg/m²) with suspected CAD who underwent stress/rest radionuclide myocardial perfusion imaging (MPI) at the Department of Nuclear Medicine, the Third Affiliated Hospital of Soochow University between January 1, 2022 and December 31, 2024. Patients were divided into myocardial ischemia group and non-ischemia group based on MPI findings. MAFLD diagnosis was determined based on hepatic steatosis detected by low-dose CT integrated with single-photon emission computed tomography/CT (SPECT/CT), combined with established diagnostic criteria (no excessive alcohol consumption plus presence of metabolic dysfunction). Univariate and multivariate logistic regression models were applied to analyze the correlation between MAFLD and myocardial ischemia. Stratified analyses were further performed according to BMI (normal weight: 18.5 kg/m²≤BMI<24.0 kg/m²; overweight: 24.0 kg/m²≤BMI<28.0 kg/m²) and coronary angiography results (obstructive or non-obstructive CAD) to assess the relationship between MAFLD and myocardial ischemia in each subgroup. Results: A total of 271 patients with suspected CAD were enrolled, aged (61.6±10.2) years, with 143 (52.8%) males. There were 135 patients in the myocardial ischemia group and 136 in the non-ischemia group. MAFLD was diagnosed in 88 patients (32.5%). The proportion of patients diagnosed with MAFLD was higher in the myocardial ischemia group than in the non-myocardial ischemia group (61 cases (45.2%) vs. 27 cases (19.9%), P<0.001). Multivariate logistic regression analysis showed that MAFLD was independently associated with myocardial ischemia (OR=3.43, 95%CI 1.85-6.28, P<0.001). Subgroup analysis revealed that MAFLD was associated with myocardial ischemia in both normal weight group (OR=7.62, 95%CI 2.48-23.44, P<0.001) and overweight group (OR=2.60, 95%CI 1.20-5.60, P=0.015), with a stronger association observed in normal-weight individuals. This association also existed in non-obstructive CAD group (OR=6.50, 95%CI 2.23-18.94, P<0.001) and obstructive CAD group (OR=3.05, 95%CI 1.37-6.80, P=0.006). Conclusion: MAFLD acts as an independent risk factor for myocardial ischemia in non-obese patients with suspected CAD, and this association persists across subgroups stratified by BMI (normal weight vs. overweight) and coronary lesion phenotype (obstructive vs. non-obstructive CAD).