Coronary plaque tissue characterization in patients with premature coronary artery disease

Premature coronary artery disease (CAD) studies rarely involve coronary plaque characterization. We characterize coronary plaque tissue by radiofrequency intravascular ultrasound (IVUS) in patients with premature CAD. From July 2015 to December 2017, 220 patients from the Department of Cardiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine with first occurrence of angina or myocardial infarction within 3 months were enrolled. Patients with premature CAD (n = 47, males aged < 55 years, and females aged < 65 years) or later CAD (n = 155) were retrospectively compared for cardiovascular risk factors, laboratory examination findings, coronary angiography data, gray-scale IVUS, and iMap-IVUS. The mean age was 53.53 ± 7.24 vs. 70.48 ± 8.74 years (p < 0.001). The groups were similar for traditional coronary risk factors except homocysteine (18.60 ± 5.15 vs. 17.08 ± 4.27 µmol/L, p = 0.043). After matching for baseline characteristics, LDL cholesterol (LDL-C) was higher for premature CAD than later CAD (2.50 ± 0.96 vs. 2.17 ± 0.80 mmol/L, p = 0.019). Before the matching procedure, the premature CAD group had shorter target lesion length [18.50 (12.60-32.00) vs. 27.90 (18.70-37.40) mm, p = 0.002], less plaque volume [175.59 (96.60-240.50) vs. 214.73 (139.74-330.00) mm³, p = 0.013] than the later CAD group. After the matching procedure, the premature CAD group appeared to be less plaque burden (72.69 ± 9.99 vs. 74.85 ± 9.80%, p = 0.005), and positive remodeling (1.03 ± 0.12 vs. 0.94 ± 0.18, p = 0.034), and lower high risk feature incidence (p = 0.006) than the later CAD group. At the plaque's minimum lumen, premature CAD had more fibrotic (p < 0.001), less necrotic (p = 0.001) and less calcified areas (p = 0.012). Coronary plaque tissue was more fibrotic with less necrotic and calcified components in premature than in later CAD, and the range and degree of atherosclerosis were significantly lower.