Author + information
- Sho Hashimoto1,
- Akihiko Takahashi2,
- Takeshi Yamada3,
- Yukio Mizuguchi4,
- Norimasa Taniguchi5,
- Shunsuke Nakajima6 and
- Tetsuya Hata7
Recently, excimer laser coronary angioplasty (ELCA) with angiographic or intra vascular ultrasound guidance failed to show its superiority over the conventional balloon angioplasty for treating in-stent restenosis (ISR). We evaluated the clinical significance of applying optical coherence tomography (OCT) in ELCA for the ISR with drug eluting stent (DES).
Between April 2014 and May 2016, 43 DES-ISR lesions (39 patients) were treated with ELCA under OCT guidance. OCT evaluation was conducted before, after ablation with ELCA and the end of the procedures. Based on the morphological assessment by OCT of neointimal tissue at the minimum lumen area (MLA) site, the lesions were categorized into the 3 groups: Homogenous group, layered group, and mixed group. The first pass of ELCA was performed with a fluence of 45 mJ/mm2 and a repetition rate of 25 Hz. The maximum fluence and repetition rate used in the ablation was 60 mJ/mm2 and 40 Hz. The endpoint of ELCA was determined at the operators’ discretion, mainly by 1) formation of any dissection, which may cause larger dissection, requiring stent implantation by further ablation, 2) exposure of any stent strut in the lesion, and 3) long ablation time (>10 min). After ELCA, additional balloon dilatation was performed with a scoring and drug coated balloon catheter. OCT was used to assess the MLA each stage of the procedure and the lumen gain was calculated and compared among the three groups.
The OCT findings revealed 13 homogenous, 18 layered and 12 mixed type lesions. We found no significant difference in the initial MLA (1.23±0.53 mm2 vs. 1.27±0.61 mm2 vs. 1.01±0.61, P=0.490) and after ELCA MLA (1.81±0.65 mm2 vs. 1.91±0.67 mm2 vs. 1.97±0.67, P=0.853) between the 3 groups. Final lumen gain (difference between final MLA and initial MLA) in the homogeneous group (3.06±1.49 mm2) was significantly smaller than the layered group (4.11±1.34 mm2, P=0.048) or the mixed group (4.46±1.85 mm2, P=0.048).
Effectiveness of ELCA and subsequent balloon dilatation for ISR depend upon the type of tissue accumulated in the stent luminal area, which can be detected with OCT guidance.