Management of patients with in-stent restenosis (ISR) remains an important clinical problem. Although drug-eluting stents (DES) have drastically reduced the incidence of ISR, treatment of DES-ISR is particularly challenging. ISR mainly results from aggressive neointimal proliferation, but recent data also suggest that neoatherosclerosis may play an important pathophysiological role. Intracoronary imaging provides unique insights to unravel the underlying substrate of ISR and may be used to guide repeated interventions. In this paper, we systematically reviewed clinical trial data with currently available therapeutic modalities, including DES and drug-coated balloons, in patients presenting with ISR within bare-metal stents or DES.

In patients with DES-ISR, EES provided superior long-term clinical and angiographic results compared with DEB. (Restenosis Intra-Stent of Drug-Eluting Stents: Drug-Eluting Balloon vs Everolimus-Eluting Stent [RIBS IV]; NCT01239940).

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The 3-year clinical follow-up of the RIBS V clinical trial confirms the sustained safety and efficacy of EES and DEB in patients treated for bare-metal stent ISR. In this setting, EES reduce the need for target lesion revascularization at very long-term follow-up. (RIBS V [Restenosis Intra-Stent of Bare Metal Stents: Paclitaxel-Eluting Balloon vs Everolimus-Eluting Stent] [RIBS V]; NCT01239953).

Spontaneous coronary artery dissection (SCAD) remains an infrequent, elusive, and challenging clinical entity of unknown etiology eight decades after its initial description. Our understanding of the pathophysiology of SCAD, initially limited to information from early pathological studies, case reports, and very short series, has been enriched recently by relatively large contemporary series of patients studied prospectively. The typical presentation involves a young woman without coronary risk factors suffering an acute coronary syndrome but, actually, most patients are middle-aged and have coronary risk factors. A high number of conditions have been related to SCAD, but fibromuscular dysplasia has shown a major intriguing association with potential pathophysiological implications. SCAD may present (a) with an intimal tear and the classic angiographic 'flap' leading to the appearance of two lumens (true and false), or (b) without an intimal rupture, as an intramural hematoma. An increased clinical awareness together with new diagnostic tools have led to a major surge in the diagnosis of SCAD. High-resolution intracoronary techniques provide unique diagnostic insights into the underlying pathophysiology and facilitate identification of the disease in patients misdiagnosed previously. After the initial acute ischemic insult, most patients stabilize and have a benign clinical course and eventually experience spontaneous healing of the vessel wall during follow-up. However, recurrences may still occur in up to 10-20% of cases. Accordingly, a conservative medical management (watchful waiting strategy) has been recommended as the initial approach. Revascularization remains particularly challenging and may be associated with suboptimal results, acute complications, and poor long-term outcome. Nevertheless, in patients with ongoing or refractory ischemia and adequate anatomy, revascularization should be attempted. Some novel and attractive coronary interventions have been proposed in this uniquely challenging anatomic scenario. This review aims to present a comprehensive and contemporary update on this elusive and intriguing clinical entity.

The potential use of Gold Nanoparticles (GNPs) as contrast agents for clinical intracoronary frequency domain Optical Coherence Tomography (OCT) is here explored. The OCT contrast enhancement caused by GNPs of different sizes and morphologies has been systematically investigated and correlated with their optical properties. Among the different GNPs commercially available with plasmon resonances close to the operating wavelength of intracoronary OCT (1.3 µm), Gold Nanoshells (GNSs) have provided the best OCT contrast due to their largest scattering cross section at this wavelength. Clinical intracoronary OCT catheters are here demonstrated to be capable of three dimensional visualization and real-time tracking of individual GNSs. Results here included open an avenue to novel application of intravascular clinical OCT in combination with GNPs, such as real time evaluation of intravascular obstructions or pressure gradients.

Myocardial injury is frequently detected in coronavirus disease 2019 (COVID‐19) patients. However, up to one‐third of COVID‐19 patients showing ST‐segment elevation on the electrocardiogram have angiographically normal coronary arteries. We present a case of an acute coronary syndrome due to a coronary spasm in a severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) patient. This pathophysiological mechanism was clearly demonstrated by intracoronary imaging techniques (optical coherence tomography) and invasive vasospasm test.

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