Background: Preliminary research indicates that higher iron levels are associated with worse outcomes in patients with coronary artery disease.
Aims: The study aimed to investigate the relationship between iron levels and the type and composition of coronary plaques.
Methods: In patients with ≥1 coronary stenosis ≥50% on computed tomography angiography, iron levels, presence of high-risk plaque features, such as low-attenuation plaque (LAP), napkin-ring sign, positive remodeling, and spotty calcium, as well as type and plaque composition (calcified/fibrous/fibro-fatty/necrotic core) were evaluated. Fibro-fatty and necrotic core components were analyzed together as vulnerable component.
Results: The study included 300 patients (191 men, 62.2 [23.0] years). Two thousand one hundred and eighty-four plaques were found (1201 calcified, 584 non-calcified, and 397 mixed). High-risk plaque was observed in 208 patients (107 LAP, 54 napkin-ring signs, 354 positive remodeling, and 281 spotty calcium). Patients with LAP had higher iron levels (P <0.0001). In univariable regression, LAP predictors were high iron levels (odds ratio [OR], 1.02; 95% CI, 1.00-1.03; P <0.0001), male sex (OR, 2.50, 95% CI, 1.40-4.46; P = 0.002), and hemoglobin (OR, 1.23; 95% CI, 1.01-1.49; P = 0.04). In multivariable regression, only iron and male sex were LAP predictors (OR, 1.02; 95% CI, 1.01-1.03; P = 0.0002, and OR, 2.41; 95% CI, 1.24-4.70; P = 0.009, respectively). The iron threshold for LAP prediction was >98 μg/dl (AUC 0.665; P <0.001), which corresponds with an OR of 3.2 (95% CI, 1.80-5.80; P = 0.0001) for LAP prediction. Higher iron correlated with more fibro-fatty (P = 0.01) and necrotic core (P = 0.02) components, with no relation to calcified and fibrous components. Higher iron was positively correlated with the percentage of vulnerable plaque component (P = 0.004).
Conclusions: Higher iron levels were associated with LAP presence and more vulnerable component of coronary atherosclerotic plaques.
Keywords: atherosclerosis; coronary artery disease; iron; low attenuation plaque; vulnerable plaque.