Author + information
- Sho Hashimoto,
- Akihiko Takahashi,
- Takeshi Yamada,
- Yukio Mizuguchi,
- Norimasa Tanicuchi,
- Shunsuke Nakajima and
- Tetsuya Hata
The effect of excimer laser coronary angioplasty (ELCA) for in-stent restenosis (ISR) in bare-metal stent has been proved to be ineffective when conducted under angiography or intravascular ultrasound guidance. We sought to evaluate the clinical significance of tissue characteristics assessed by optical coherence tomography (OCT) on acute mid-term result of ELCA for ISR in drug-eluting stent era.
Between April 2014 and November 2015, 41 in-stent (7 bare metal stents and 34 drug eluting stents) restenosis lesion were treated with ELCA catheter with maximum fluence of 60 mJ/mm2 and maximum repetition rate of 40 Hz. After ECLA ablation, additional balloon dilatation with either scoring balloon catheter or non-compliant balloon catheter was conducted. Procedure was finalized with application of drug carted balloon catheter. During PCI procedure, tissue characterization and lumen measurement with OCT was performed three times: 1) before PCI, 2) after ablation with ELCA and 3) at the end of procedure. Based on the initial OCT findings, the lesions were categorized into the 3 groups: 1) homogenous group, 2) layered group and 3) mixed group. For each patient (lesion), follow-up angiogram (without OCT) was conducted 9-12 months after the PCI.
The lesions were categorized into 15 homogenous, 17 layered and 9 mixed type lesions. No significant difference was observed in the initial MLA between the three groups (1.09 ± 0.32 mm2, 1.17 ± 0.67 mm2, 1.44 ± 0.75 mm2, respectively P=0.16). After ELCA, MLA in the mixed group (2.40 ± 0.66 mm2) was larger than that in the layered group (1.72 ± 0.49 mm2, P=0.01) and the homogeneous group (1.81 ± 0.92 mm2, P=0.08). Final MLA in the mixed group (5.66 ± 1.52 mm2, P=0.01) was larger than that in the homogeneous group (3.84 ± 1.63 mm2, p=0.01) and the layered group (4.95 ± 1.93 mm2, P=0.09).
The follow-up angiogram after 9-12 month revealed no significant difference in terms of ISR ratio (homogeneous 46.6%, layered, 29.4%, mixed 44.4%; P=0.578). There was no difference in target lesion revascularization rate (TLR: homogeneous 26.6%, layered 23.5%, mixed 33.3% respectively P=0.88).
In treatment for ISR, effectiveness of ELCA in acute phase depends upon the tissue characteristics detected by OCT. Despite these difference observed in acute phase, no difference was observed in ISR and TLR rates after 9-12 month.