Atherosclerotic plaques express high levels of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), with plaque regions particularly prone to instability showing accentuated LOX-1 abundance. The proinflammatory milieu within atherosclerotic plaques enhances LOX-1 synthesis, promotes LOX-1 shedding, and thus soluble LOX-1 (sLOX-1) release. The turnover of membrane-bound LOX-1 determines plaque composition and thus stability, with systemically circulating sLOX-1 emerging as a novel biomarker reflecting plaque burden and vulnerability. In this multicentre prospective cohort study, it was found that plasma levels of sLOX-1 are markedly elevated in patients presenting with acute coronary syndromes (ACS) when compared with both chronic coronary syndrome (CCS) and healthy subjects (CTRL). High sLOX-1 levels were independently associated with a higher multivariable-adjusted 1-year mortality risk following ACS, a finding that remained consistent after controlling for GRACE 2.0. In patients subjected to serial intravascular ultrasound following the index ACS, sLOX-1 dropped markedly in those with coronary plaque regression, while persistently high sLOX-1 levels were associated with plaque progression. §Adjusted for sex, age, ACS type, hs-CRP, history of hypercholesterolaemia, eGFR, LDL-C, and diagnosis of diabetes; †adjusted for sex, age, ACS type, hs-CRP, history of hypercholesterolaemia, eGFR, LDL-C, diagnosis of diabetes, NT-proBNP, and hs-TnT. ADAM, a disintegrin and metalloproteinase; GRACE, Global Registry of Acute Coronary Events; IVUS, intravascular ultrasound; MMP, matrix metalloproteinase; LOX-1, lectin-like oxidized low-density lipoprotein receptor-1; sLOX-1, soluble LOX-1.²¹