Influence of treatment modality and neointimal characteristics on optical coherence tomography on clinical outcomes of in-stent restenosis

Abstract Background In-stent restenosis (ISR) represents the more frequent modality of stent failure. The currently recommended treatment strategies are represented by repeat drug-eluting stent (DES) implantation or drug-coated balloon (DCB) angioplasty. Optical coherence tomography can display important information regarding mechanisms of stent failure as well as neointimal characterization. Purpose Aim of the present study was to determine the impact of treatment modality (DES vs. DCB) as well as neointimal characteristics (homogeneous vs. non-homogeneous) as determined by intravascular OCT, on clinical outcomes and explore whether there is an interaction between neointimal pattern of ISR and treatment modality. Methods Patients presenting with ischemic symptoms and/or evidence of myocardial ischemia in three European centers and undergoing intravascular OCT prior to percutaneous coronary intervention (PCI) for ISR, were retrospectively included in this study. Characterization of neointimal tissue was performed at the frame displaying the maximal %AS as well as the 5 preceding and following analyzed frames. Each frame was subdivided in 4 quadrants (90°) and the neointimal characteristics separately characterized for each of them. Based on its optical characteristics, neointimal tissue was categorized as homogeneous, heterogeneous, layered or neoatherosclerosis. Based on the dominant neointimal type, the study population was divided in two groups, (predominantly homogeneous and non-homogeneous). Primary endpoints of the study were represented by major adverse cardiac events (MACE) and its idividual components (death, cardiac death, myocardial infarction and target lesion revascularization (TLR)) at 2 years follow-up. Results A total of 197 patients undergoing OCT prior to PCI for ISR were included in this study. 100 patients were classified as having predominantly homogeneous and 97 as having predominantly non-homogeneous neointima. No association was found between predominant OCT pattern (homogenous vs. non-homogenous) and MACE at 2 years follow-up (HR=1.01, 95% CI: 0.59–1.75; p=0.94), or the individual MACE components. Analogously, no significant differences in terms of MACE at 2 years were found between predominantly homogeneous vs. non-homogeneous neointima in the patient subgroup receiving a DES (p=0.10) and in that undergoing DCB treatment (p=0.11). However, a significant interaction was found between neointimal tissue pattern and treatment modality in terms of MACE (p=0.02) aa well as death or MI (p=0.016). Predominantly non-homogeneous neointima in patients treated with DCB was associated with a higher incidence of MACE. Conclusions Our results indicate that there is a significant interaction between treatment modality of ISR (DES vs. DCB) and neointimal pattern as determined by intravascular OCT. These results land initial support to an OCT-guided treatment of ISR and should be confirmed by larger trials. Funding Acknowledgement Type of funding source: None