CHI3L1 was the most relevant upregulated protein identified in HF RCA samples, which was (i) differentially expressed between CTRL, pre-ATH, and ATH samples, (ii) strongly associated with plaque size/extent and Stary stage, and (iii) immunohistologically related to a prevalent VSMC plaque composition. The gene discussed is CHI3L1; the disease is hydrops fetalis.