Neoatherosclerosis: from basic principles to intravascular imaging.

Development of new atherosclerotic lesions within the neointima of stented vessels has been recognized as a novel disease manifestation of atherosclerosis (neoatherosclerosis), often manifesting as in-stent restenosis (ISR) or in-stent thrombosis (ST). The pathobiology of this entity is still not fully understood and definite diagnosis is challenging owing to limitations in resolution of contemporary intravascular imaging modalities and lack of consequent histopathology correlation studies. Yet, intravascular imaging has emerged as the gold standard for the diagnosis of in-stent pathologies, the most routinely used modalities being intravascular ultrasound (IVUS) and optical coherence tomography (OCT). In this review, we will give a concise summary about the basic understanding and histological findings of neoatherosclerosis. We will focus on the description of in-vivo findings using IVUS and OCT, discussing advantages and pitfalls. Furthermore, recent developments regarding innovative molecular imaging techniques for a more precise and advanced examination of neoatherosclerotic plaques will be discussed.