Iron levels and vulnerable coronary atherosclerotic plaques

Preliminary research indicates that higher iron levels are associated with worse outcomes in patients with coronary artery disease.

The study aimed to investigate the relationship between iron levels and the type and composition of coronary plaques.

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.

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).

Higher iron levels were associated with LAP presence and more vulnerable component of coronary atherosclerotic plaques.