Angiographic No-Reflow in Patients With Acute Coronary Syndrome Caused by Calcified Nodules

Acute coronary syndrome (ACS) caused by calcified nodules (CNs) has a poor prognosis. The no-reflow phenomenon in CNs has not been well studied. We investigated the incidence of the no-reflow phenomenon, evaluated the relationship between the no-reflow phenomenon and plaque components in patients with ACS caused by CNs, and compared the clinical outcomes on the basis of plaque morphology and components. This study enrolled 355 ACS patients who had de novo culprit lesions in a native coronary artery. The culprit lesions were assessed by both optical coherence tomography (OCT) and near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS). The patients were classified into 3 groups according to OCT findings (plaque rupture [PR], plaque erosion [PE], or CN), and then respectively divided into 2 groups using a maximum lipid core burden index in 4 mm (maxLCBI_4mm) cutoff value of 400 on NIRS-IVUS. The maxLCBI_4mm in the infarct-related lesion was greater in patients with PR (641 [461-772]) than in those with PE (vs 533 [373 to 713], p = 0.004) and CN (vs 479 [342 to 639], p = 0.002). In patients with CN, the maxLCBI_4mm was significantly greater in patients with the no-reflow phenomenon than in those without (p = 0.027). The incidence of major adverse cardiovascular events was significantly higher in patients with CN and a maxLCBI_4mm ≥400 than in those with other plaque features (p = 0.024). Underlying lipidic components are associated with the no-reflow phenomenon in CNs. CNs and a large lipid core provide worse long-term clinical outcomes after percutaneous coronary intervention in ACS.