Clinical outcomes by optical characteristics of neointima and treatment modality in patients with coronary in-stent restenosis.

Background: Drug-coated balloons (DCB) and drug-eluting stents (DES) represent the currently recommended treatments for in-stent restenosis (ISR). Optical coherence tomography (OCT) allows detailed neointimal characterisation which can guide treatment strategies.

Aims: The aims of this study were first, to assess the relation between neointimal pattern and clinical outcomes following in-stent restenosis (ISR) treatment, and second, to explore a potential interaction between neointimal pattern and treatment modality relative to clinical outcomes.

Methods: Patients undergoing OCT-guided treatment (DCB or DES) of ISR in three European centres were included. Based on the median of distribution of non-homogeneous neointima quadrants, patients were categorised into low and high inhomogeneity groups.

Results: A total of 197 patients (low inhomogeneity=100 and high inhomogeneity=97) were included. There were no significant differences in terms of major adverse cardiac events (MACE) (p=0.939) or target lesion revascularisation (TLR) (p=0.732) between the two groups. The exploratory analysis showed a significant interaction between neointimal pattern and treatment modality regarding MACE (pint=0.006) and TLR (pint=0.022). DES showed a significant advantage over DCB in the high (MACE: HR 0.26 [0.10-0.65], p=0.004; TLR: HR 0.28 [0.11-0.69], p=0.006), but not in the low inhomogeneity group (MACE: p=0.917; TLR: p=0.797).

Conclusions: In patients with ISR treated with DCB or DES, there were no significant differences in terms of MACE or TLR between the low and high inhomogeneity groups. A significant interaction was observed between treatment modality and neointimal pattern with an advantage of DES over DCB in the high and no difference in the low inhomogeneity group. This warrants confirmation from prospective dedicated studies.