Calcified Nodules: Pathology, Mechanisms, and Clinical Challenges.

PURPOSE OF REVIEW: Calcified nodules (CNs) account for ~ 5% of acute coronary syndrome cases. Although the progression of calcification generally leads to plaque stability, CNs ─ an advanced form of calcified plaques ─ can trigger coronary thrombosis and sudden cardiac death.

RECENT FINDINGS: CNs are histologically defined as lesions with fibrous cap disruption and luminal thrombus, associated with dense, eruptive calcific nodules protruding into the lumen. They are linked to poor prognosis both post percutaneous coronary intervention and in non-culprit lesions. Interventionalists are exploring various treatment strategies using debulking devices and drug-coated balloons; however, no effective treatment has been established. While histological classifications can be inferred from optical coherence tomography findings, accurately predicting CNs from intravascular imaging remains challenging. This review discusses the pathological features, etiology, clinical outcomes, and current treatment strategies for CNs, offering valuable insights into the correlation and discrepancies between histological findings and optical coherence tomography.