A novel cardiac computed tomography-based calcium scoring system for predicting the use of debulking devices in severely calcified coronary lesions: CT-CALC score

Abstract Background Cardiac CT is a well-established diagnostic tool for coronary artery disease, aiding in optimizing patient selection for percutaneous coronary intervention (PCI) and facilitating the planning and guidance of therapeutic interventions beyond the diagnostic phase. However, a definitive parameters based on CT imaging to predict the need for debulking devices such as rotational atherectomy (RA) and orbital atherectomy (OAS), have not yet been established. Purpose This study aimed to develop a risk score to predict the use of debulking devices in PCI based on preoperative cardiac CT morphological findings. Methods In this retrospective, multicenter, observational study in Japan, patients who underwent PCI were screened. Inclusion criteria were: (1) cardiac CT within 6 months prior to PCI, (2) moderate or severe coronary calcification detected on CT, and (3) de novo lesions in native coronary arteries.A total of 498 lesions in 415 patients from 14 hospitals were included in the study. Seventy percent of the randomly selected cohort (derivation cohort, 349 lesions) was used to develop the risk prediction model, and the remaining 30% (validation cohort, 149 lesions) was used to evaluate their discriminative ability and calibration (Figure 1A).Cardiac CT images were analyzed for the circumferential angle, longitudinal distance, intracoronary distribution of calcification, shape, peak density, mean density, vessel bending, and the presence of bifurcation lesions. Odds ratios were estimated using logistic regression model. Results Multivariable analysis in the derivation cohort identified four factors: circumferential angle ≥ 270˚, longitudinal distance ≥ 9 mm, bifurcation, and calcified nodule (Figure 1B). The risk prediction model was translated into a point-based simple risk score.The validity of the risk prediction model was evaluated using c-statistics and the Hosmer-Lemeshow test in the validation cohort (n=149). The c-statistic was 0.85 (95% CI: 0.79–0.91) in the validation cohort. Figure 2 shows a comparison between the observed and model-predicted risks of debulking device use across the four risk groups. The predicted risks of debulking device use were similar to the observed risks in the validation cohort (Hosmer-Lemeshow goodness-of-fit test, p=0.31). Conclusions The developed model accurately predicted the use of debulking devices in a cohort of patients with moderate to severe coronary calcification. Estimating debulking devices use by preoperative cardiac CT with an easily applicable objective tool has the potential for widespread implementation in clinical settings.Figure 1 Figure 2