Coexistence of Calcification and Lipids: A Hidden Barrier to Optimal Stent Expansion　― Reply ―

We thank Dr. Iwaya and colleagues for their thoughtful letter regarding our study described in “Predictors of stent underexpansion for severely calcified lesions after debulking.”¹

Previous studies^2,3 have primarily focused on the severity and morphological characteristics of calcified lesions in the context of percutaneous coronary intervention, but, as we found,¹ ≈45% of severely calcified lesions also contain lipid-rich components and the borderline between the calcified and lipid-rich areas plays a critical role in stent underexpansion (SUE), which is associated with worse clinical outcomes.^2,4 This finding underscores the importance of careful assessment of lipid-rich tissue, particularly after optimal debulking of severely calcified lesions. As Dr. Iwaya et al. noted, intensive lipid-lowering therapy is crucial in managing lesions that include both calcified and lipid-rich plaque.

To minimize the risk of SUE in severely calcified lesions, initial lesion modification using modalities such as rotational atherectomy, orbital atherectomy, or intravascular lithotripsy is essential.⁵ After optimal debulking of the calcified lesions, if the lesion consists predominantly of calcified plaque, stent implantation is generally appropriate. However, for lesions with both calcified and lipid-rich components, a stent-free strategy combined with aggressive lipid-lowering therapy may offer advantages. Further large-scale clinical studies are needed to validate this proposed treatment approach.

• Masami Nishino, MD, PhD, FACC, FESC
• Yasuyuki Egami, MD
• Naotaka Okamoto, MD
• Yasuharu Matsunaga-Lee, MD
• Masamichi Yano, MD, PhD
• Division of Cardiology, Osaka Rosai Hospital, Sakai, Japan

References

• 1.   Nishino M, Egami Y, Okamoto N, Sugino A, Kobayashi N, Abe M, et al. Predictors of stent underexpansion for severely calcified lesions after debulking. Circ J 2025; 89: 1121–1128.
• 2.   Fujino A, Mintz GS, Matsumura M, Lee T, Kim SY, Hoshino M, et al. A new optical coherence tomography-based calcium scoring system to predict stent underexpansion. EuroIntervention 2018; 13: e2182–e2189.
• 3.   Matsuhiro Y, Nakamura D, Shutta R, Yanagawa K, Nakamura H, Okamoto N, et al. Maximum calcium thickness is a useful predictor for acceptable stent expansion in moderate calcified lesions. Int J Cardiovasc Imaging 2020; 36: 1609–1615.
• 4.   Nakamura D, Attizzani GF, Nishino S, Tanaka K, Soud M, Pereira GT, et al. New insight to estimate under-expansion after stent implantation on bifurcation lesions using optical coherence tomography. Int J Cardiovasc Imaging 2017; 33: 1677–1684.
• 5.   Saito S, Yamazaki S, Takahashi A, Namiki A, Kawasaki T, Otsuji S, et al. Intravascular lithotripsy for vessel preparation in severely calcified coronary arteries prior to stent placement: Primary outcomes from the Japanese Disrupt CAD IV Study. Circ J 2021; 85: 826–833.