難治性多層ステント内再狭窄に対するレーザー支援OPN法：系統的アプローチ

Multilayer in-stent restenosis (ISR) with severe stent underexpansion represents a challenging clinical scenario with limited effective treatment options when conventional interventions fail, despite all our current advances in interventional cardiology.

We present a 65-year-old man with recurrent angina despite multiple prior right coronary artery interventions, including intravascular lithotripsy and drug-eluting stent implantation. Optical coherence tomography revealed triple-layer stent restenosis with severe underexpansion refractory to noncompliant balloon and OPN super-high-pressure balloon dilation. The patient was referred to a specialized center, where contrast-enhanced excimer laser coronary atherectomy (ELCA) combined with OPN balloon angioplasty (L-OPN technique) was performed. Intravascular ultrasound-guided ELCA (1.4-mm catheter, 60 mJ/mm² × 60 Hz, 6 runs with contrast) followed by OPN balloon at 40 atm achieved significant improvement in minimum lumen diameter (from 1.8 × 1.9 mm to 2.6 × 3.1 mm) and minimum lumen area (6.7 mm²). The procedure was completed with drug-eluting balloon therapy and ostial stenting.

This case illustrates the systematic L-OPN approach for treating complex multilayer ISR when conventional methods have failed. Contrast-enhanced ELCA generates rapidly expanding microbubbles creating acoustic pressures that can disrupt calcified and fibrotic tissue surrounding underexpanded stents, facilitating subsequent balloon expansion. Intravascular ultrasound guidance was critical for assessing baseline underexpansion and confirming an adequate final result.

When conventional balloon angioplasty and intravascular lithotripsy fail to achieve adequate stent expansion in multilayer ISR, the combination of contrast-enhanced ELCA followed by OPN super-high-pressure balloon (L-OPN technique) guided by intravascular imaging offers a viable therapeutic option.