Clinical implications of calcification severity adjacent to calcified nodule: Its association with first and recurrent risks of target lesion revascularization after percutaneous coronary intervention.

Background And Aims: Calcified nodule (CN) is a plaque phenotype characterized by protruding calcification, associated with repeat revascularization after percutaneous coronary intervention (PCI). The severity of calcification increases the risk of future target lesion revascularization (TLR). This study was conducted to determine whether calcification severity in the adjacent zone is associated with TLR.

Methods: We analyzed 204 patients who received PCI for de-novo CN using intravascular ultrasound (IVUS). The calcium volume index (CVI) was calculated for each 1-mm cross-sectional frame in both the CN and adjacent zones.

Results: TLR occurred in 63 patients (30.9 %) during a median follow-up period of 2.8 years (interquartile range, 2.4-3.2). CVIs in both the CN and adjacent zones, along with minimum lumen area (MLA) after PCI, were significant predictors of TLR. The ROC curve-derived values for the CVIs in the CN and adjacent zones (10.52 and 5.33, respectively) and the MLA after PCI (6.65 mm) were associated with higher TLR incidence. Among those requiring TLR, 27.0 % experienced multiple TLRs, with higher CVIs associated with recurrence. In a multi-state model, CVIs in both the CN and adjacent zones were significantly associated with the first TLR (no TLR as reference) and the second TLR (first TLR as reference). The CVI in the adjacent zone showed a higher hazard ratio for the second TLR (1.31; 95 % confidence interval [CI]: 1.16-1.48) compared to the first TLR (1.12; 95 % CI: 1.07-1.17).

Conclusions: Our findings highlight the importance of not only the calcification severity in the CN zone, but also in the adjacent zones, for TLR.