Stepwise intracoronary imaging assessment of lumen and vessel changes during drug-coated balloon angioplasty for in-stent restenosis

Drug-coated balloon (DCB) angioplasty is an established treatment for in-stent restenosis (ISR), and its procedural success mainly depends on optimal lesion preparation. However, angiography alone offers limited assessment of acute procedural effects, and the sequential vessel and lumen changes have not been comprehensively characterized with intracoronary imaging (ICI).

Amid the continuing debate on the optimal DCB strategy, we aimed to characterize stepwise vessel and lumen changes during DCB angioplasty for ISR across three procedural stages: pre-lesion preparation, post-lesion preparation and post-DCB inflation, using intravascular ultrasound (IVUS) or optical coherence tomography (OCT).

This single-center, retrospective study included 20 patients (21 ISR lesions) undergoing ICI-guided DCB angioplasty with available imaging pullbacks at three stages: pre-lesion preparation (T1), post-lesion preparation (T2), and post-DCB inflation (T3). The vessel segment treated with DCB was identified on angiography and co–registered across all three pullbacks using reproducible landmarks, including the initial position of the ICI detector, previously implanted stents, and nearby side branches. This defined the region of interest (ROI), within which all study measurements were performed. Quantitative coronary angiography (QCA), IVUS, and OCT analyses were performed offline by a single trained observer. Changes in lumen and vessel parameters between stages were assessed using the Wilcoxon signed-rank test, where sample size permitted.

Median [25th – 75th percentile] age was 69 [63 – 72] years, and 15 (75%) were male. Lesion preparation was mainly performed with non-compliant balloons (76%). QCA showed an incremental increase in minimal lumen diameter after lesion preparation (median difference (95% confidence interval) +0.6 (0.2 – 1.0) mm, p<0.001) followed by a smaller, yet significant gain after DCB (+0.2 (0.1 – 0.4) mm, p<0.01). On ICI, minimal lumen area increased after lesion preparation (IVUS: +2.6 (1.8 – 2.7) mm², p<0.001; OCT: +2.0 mm²) and further after DCB (IVUS: +0.6 (0.4 – 1.1) mm², p<0.001; OCT: +0.6 mm²) (Figure 1). Plaque and neointimal burden decreased progressively after lesion preparation and DCB. The lesion optical flow ratio gradient markedly declined after lesion preparation (Figure 2).

This study provides the first three-stage ICI evaluation of DCB angioplasty for ISR. The principal morphological and physiological changes occur during lesion preparation, which achieves most of the acute lumen gain and plaque modification. DCB inflation contributes a smaller but significant additional effect, suggesting a limited mechanical and primarily pharmacologic role. These findings highlight the central importance of adequate lesion preparation and support the use of ICI for optimizing DCB angioplasty.Figure 1For image description, please refer to the figure legend and surrounding text.  Figure 2For image description, please refer to the figure legend and surrounding text.