Identification and treatment of calcified nodules in percutaneous coronary intervention

Calcified nodules (CNs) represent significant challenges in percutaneous coronary intervention (PCI) due to their complex morphology, variable treatment responses, and association with stent failure due to reprotrusion or stent underexpansion. CNs are classified into eruptive and non-eruptive subtypes, each with distinct histological features and prognostic implications. Eruptive CNs are biologically active, being associated with a disrupted fibrous cap, overlying thrombus, and intraplaque haemorrhage, and they are thus more readily deformable by balloon dilation during PCI. Non-eruptive CNs, or nodular calcifications, tend to be stable, with an intact fibrous cap, and their deformability varies depending on the composition and base of the nodules. Enhanced angiography and intravascular imaging have greatly improved our understanding of CNs and may help to accurately identify nodule subtypes and guide treatment. Furthermore, understanding the deformability of CNs is crucial for optimising treatment outcomes. In this review, we discuss the identification and management of CNs in the context of PCI.