Predicting the need for calcium modification techniques using computed tomography coronary angiography

Calcified coronary arteries pose a challenge to percutaneous coronary intervention (PCI). Calcium modification techniques (CMTs) increase procedural length, complexity and risk. Computed tomography coronary angiography (CTCA) is well suited to calcium identification and quantification and may offer valuable pre-procedural information. We hypothesised that CTCA could predict cases where CMT would be required during PCI. A single centre retrospective review (2021/2022) of consecutive patients who underwent PCI with a preceding CTCA demonstrating a calcified lesion in a major epicardial vessel. Blinded to the PCI strategy CTCA images were re-reviewed and calcium thickness, length, density and circumferential arc quantified. Receiver operating characteristic (ROC) curve for CMT defined optimum cut-off values. Calcium density (> 1000 HU) and calcific arc (> 180°) were proposed as a calcium planning score (CPS_CTCA), with 1 point assigned per criteria met. 76 PCI procedures were included (72 patients). CMT was used in 53% at the discretion of the operator. Calcific arc, density, length and thickness had an area under the curve (AUC) of 0.74, 0.7, 0.67 and 0.63 respectively. There was a step-wise increase in the proportion of cases requiring CMT with increasing CPS_CTCA. 0 vs. 1 point; OR 9 (1.1-82, p =.04), RR 5 (0.8-36, p =.09), 1 vs. 2 points; OR 3.2 (1.1-9.3, p =.03), RR 1.6 (1-2.3, p =.04), 0 vs. 2 points; OR 30 (3.3-272, p =.003), RR of 8 (1.3-54, p =.03). The incorporation of CTCA measured calcium density > 1000 HU and calcium arc > 180° into a calcium planning score may help with predicting the need for CMT at the time of PCI.