Optical frequency-domain imaging findings to predict good stent expansion after rotational atherectomy for severely calcified coronary lesions

We aimed to evaluate the optical frequency-domain imaging (OFDI) findings after rotational atherectomy (RA) that predict good stent expansion for severely calcified coronary lesions. Fifty consecutive calcified lesions were subjected to RA under OFDI guidance. We performed OFDI just after RA and stenting. We measured the morphology of calcium after RA, and assessed how these factors influence stent expansion. The stent expansion index was defined as the minimum stent area divided by the average of the proximal and distal reference lumen areas. Minimum thickness of calcification in the intima after RA showed a significant negative correlation with stent expansion (r = - 0.53, P < 0.001), while calcium arc, length, and maximum thickness of calcification in the intima did not. Dissection after RA occurred in 22 lesions (44%), and the stent expansion index was significantly better in dissected lesions than in lesions without dissection (0.96 +/- 0.08 vs. 0.82 +/- 0.19, P = 0.002). Multiple regression analysis showed that the minimum thickness of calcification in the intima (standardized coefficient: - 0.451, P < 0.001) and dissection formation (standardized coefficient: 0.316, P = 0.011) were predictors of good stent expansion. Minimum of thickness of calcification in the intima and dissection formation were positively associated with good stent expansion after RA. In the clinical setting, achieving these two endpoints should be the aim of RA to ensure good stent expansion.