Natural history of a newly developed calcified nodule: incidence, predictors, and clinical outcomes.

Background: Calcified nodules (CNs) are an increasingly important, high-risk lesion subset.

Aims: We sought to identify the emergence of new CNs and the relation between underlying plaque characteristics and new CN development.

Methods: Patients who had undergone two optical coherence tomography (OCT) studies that imaged the same untreated calcified lesion at baseline and follow-up were included. New CNs were an accumulation of small calcium fragments at follow-up that were not present at baseline. Cardiac death, myocardial infarction (MI), or clinically driven revascularisation related to OCT-imaged, but untreated, calcified lesions were then evaluated.

Results: Among 372 untreated calcified lesions, with a median of 1.5 (first and third quartiles: 0.7-2.9) years between baseline and follow-up OCTs, new CNs were observed in 7.0% (26/372) of lesions at follow-up. Attenuated calcium representing residual lipid (odds ratio [OR] 3.38, 95% confidence interval [CI]: 1.15-9.98; p=0.03); log₁₀ calcium volume index (length×maximum arc×maximum thickness; OR 2.76, 95% CI: 1.10-6.95; p=0.03); angiographic Δangle between systole and diastole, per 10° (OR 2.30, 95% CI: 1.25-4.22; p=0.01); and time since baseline OCT, per year (OR 1.36, 95% CI: 1.05-1.75; p=0.02) were all associated with new CN development. Clinical events were revascularisation and/or MI and were more frequent in lesions with versus without a new CN (29.3% vs 15.3%; p=0.04).

Conclusions: New CNs developed in untreated, lipid-containing, severely calcified lesions with a larger angiographic hinge motion (between systole and diastole), compared with lesions without CNs, and were associated with worse clinical outcomes.