Impact of modified vs. non-compliant balloons on tissue modifications in severely calcified lesions following atherectomy: a DIRO sub-study

Background Percutaneous coronary intervention (PCI) in severely calcified lesions is challenging due to the high incidence of difficulties in stent delivery, stent under-expansion, and the increased risk of subsequent restenosis or thrombosis.1) Scoring and cutting balloons, referred to as modified balloons (MB), are equipped with either a nitinol spiral cage or cutting blades and are commonly used for plaque modification in calcified lesions.2) These devices facilitate calcium fracturing and promote adequate lumen expansion. However, it is unclear whether tissue modification of calcified lesions differs between the use of MB and non-compliant balloons following atherectomy. Purpose This study aimed to assess calcium fractures and dissections created MB or non-compliant balloons (NC) after atherectomy, using optical coherence tomography (OCT). Methods The DIRO trial was a single-center, prospective, randomized trial comparing the efficacy of rotational or orbital atherectomy for severely calcified lesions. This sub-study included patients who underwent OCT imaging after atherectomy and balloon angioplasty. The choice between MB and NC was at the operators’ discretion. Propensity score matching using calcium arc and maximum calcium thickness was conducted, and post-balloon OCT findings were compared between MB and NC groups. Frequency-domain OCT examinations were performed with the Dragonfly imaging catheter and OPTIS imaging system during the PCI. The OCT images were analyzed offline using the Medical Offline Review Workstation at 1-mm intervals according to the current guidelines. Receiver operating characteristic curve (ROC) analysis was used to determine the cut-off values of calcium arc for fracture formation in both groups. Results We conducted OCT assessments before and after atherectomy, as well as post-dilation, in 75 patients. A total of 1,233 cross-sections with calcified plaque were analyzed in the MB group, while 507 cross-sections with calcified plaque were analyzed in the NC group. After propensity matching, 484 cross-sections were compared between both groups. The MB group showed a significantly higher incidence of calcium fractures compared to the NC group (Table 1). ROC analysis demonstrated that the cut-off value of calcium arc for calcium fracture was 204.3 degree in the NC group and 228 degree in the MB group (Figure 1). Conclusion MB resulted in a greater incidence of calcium fractures compared to NC after atherectomy in severe calcified lesions.