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Chronic total occlusions (CTO) constitute a major challenge in percutaneous coronary revascularisation (PCI). The development of new interventional strategies, the availability of purpose made tools including dedicated catheters and wires, as well as increasing expertise by the operators, have contributed to the modest success rates which today hover around 75%. Case selection is of utmost importance since failure of this high risk procedure with its typically high radiation doses, high contrast doses and increased complication rates is associated with long term adverse events. Imaging of the coronary arteries using the gold standard of invasive coronary angiography allows characterisation of the chronic total occlusion and is often able to predict the probability of successful recanalisation. Multislice computed tomography (MSCT) is increasingly being utilised as a non-invasive diagnostic imaging modality to detect coronary artery disease. Its ability to provide information on the soft tissue (including plaque) surrounding the lumen has been applied to better define the morphological features of CTOs. In fact, the amount of calcification, tortuosity and actual length of the occluded segment which are established predictors of success, are all better characterised by MSCT. Three dimensional reconstruction of the coronary anatomy and its integration with two dimensional fluoroscopy images during the actual CTO-PCI procedure may help to identify the best angiographic projection, offering a directional guide at the angiographically "missing segment". More technological advances are needed to optimise this multi-modality imaging integration. Whether this will result in better success rates for CTO-PCI is still the subject of ongoing research. It is then that we can evaluate the true benefit of the use of MSCT for CTO against the risk from excessive radiation associated with this strategy.

Aims: Angiographic evidence of edge dissections has been associated with a risk of early stent thrombosis. Optical coherence tomography (OCT) is a high-resolution technology detecting a greater number of edge dissections particularly non-flow-limiting compared to angiography. Their natural history and clinical implications remain unclear. The objectives of the present study were to assess the morphology, healing response, and clinical outcomes of OCT-detected edge dissections using serial OCT imaging at baseline and at one year following drug-eluting stent (DES) implantation. Methods and results: Edge dissections were defined as disruptions of the luminal surface in the 5 mm segments proximal and distal to the stent, and categorised as flaps, cavities, double-lumen dissections or fissures. Qualitative and quantitative OCT analyses were performed every 0.5 mm at baseline and one year, and clinical outcomes were assessed. Sixty-three lesions (57 patients) were studied with OCT at baseline and one-year follow-up. Twenty-two non-flow-limiting edge dissections in 21 lesions (20 patients) were identified by OCT; only two (9%) were angiographically visible. Flaps were found in 96% of cases. The median longitudinal dissection length was 2.9 mm (interquartile range [IQR] 1.6-4.2 mm), whereas the circumferential and axial extensions amounted to 1.2 mm (IQR: 0.9-1.7 mm) and 0.6 mm (IQR: 0.4-0.7 mm), respectively. Dissections extended into the media and adventitia in seven (33%) and four (20%) cases, respectively. Eighteen (82%) OCT-detected edge dissections were also evaluated with intravascular ultrasound which identified nine (50%) of these OCT-detected dissections. No stent thrombosis or target lesion revascularisation occurred up to one year. At follow-up, 20 (90%) edge dissections were completely healed on OCT. The two cases exhibiting persistent dissection had the longest flaps (2.81 mm and 2.42 mm) at baseline. Conclusions: OCT-detected edge dissections which are angiographically silent in the majority of cases are not associated with acute stent thrombosis or restenosis up to one-year follow-up.

Item does not contain fulltext BACKGROUND: The long-term prognostic implications of fractional flow reserve (FFR)-negative lesions hosting vulnerable plaques remain unsettled. AIMS: The aim of this study was to evaluate the association of non-ischaemic lesions hosting optical coherence tomography (OCT)-detected thin-cap fibroatheromas (TCFA) with first and recurrent cardiovascular events during follow-up up to 5 years in a diabetes mellitus (DM) patient population. METHODS: COMBINE OCT-FFR is a prospective, international, double-blind, natural history study. Patients with DM and with ≥1 FFR-negative lesion were classified into 2 groups based on the presence or absence of ≥1 TCFA lesion. The primary endpoint (PE) is a composite of cardiac mortality, target vessel-related myocardial infarction (TV-MI), clinically driven target lesion revascularisation (TLR), or unstable angina (UA) requiring hospitalisation during follow-up up to 5 years. RESULTS: Among 390 DM patients (age 67.5±9 years; 37% female) with ≥1 FFR-negative lesion, 292 (74.9%) were TCFA-negative while 98 (25.1%) were TCFA-positive. The PE occurred more frequently in TCFA-positive than in TCFA-negative patients (21.4% vs 8.2%, hazard ratio [HR] 2.89, 95% confidence interval [CI]: 1.61-5.20; p

Background:Autopsy studies have established that thin-cap fibroatheromas (TCFAs) are the most frequent cause of fatal coronary events. In living patients, optical coherence tomography (OCT) has sufficient resolution to accurately differentiate TCFA from thick-cap fibroatheroma (ThCFA) and not lipid rich plaque (non-LRP). However, the impact of OCT-detected plaque phenotype of nonischemic lesions on future adverse events remains unknown. Therefore, we studied the natural history of OCT-detected TCFA, ThCFA, and non-LRP in patients enrolled in the prospective multicenter COMBINE FFR-OCT trial (Combined Optical Coherence Tomography Morphologic and Fractional Flow Reserve Hemodynamic Assessment of Non-Culprit Lesions to Better Predict Adverse Event Outcomes in Diabetes Mellitus Patients).Methods:In the COMBINE FFR-OCT trial, patients with diabetes and ≥1 lesion with a fractional flow reserve >0.80 underwent OCT evaluation and were clinically followed for 18 months. A composite primary end point of cardiac death, target vessel-related myocardial infarction, target-lesion revascularization, and hospitalization for unstable angina was evaluated in relation to OCT-based plaque morphology.Results:A total of 390 patients (age 67.5±9 years; 63% male) with ≥1 nonischemic lesions underwent OCT evaluation: 284 (73%) had ≥1 LRP and 106 (27%) non-LRP lesions. Among LRP patients, 98 (34.5%) had ≥1 TCFA. The primary end point occurred in 7% of LRP patients compared with 1.9% of non-LRP patients (7.0% versus 1.9%; hazard ratio [HR], 3.9 [95% CI, 0.9–16.5];P=0.068; log rank-P=0.049). However, within LRP patients, TCFA patients had a much higher risk for primary end point compared with ThCFA (13.3% versus 3.8%; HR, 3.8 [95% CI, 1.5–9.5];PPP=0.38). Multivariable analyses identified TCFA as the strongest independent predictor of primary end point (HR, 6.79 [95% CI, 1.50–30.72];P=0.013).Conclusions:Among diabetes patients with fractional flow reserve-negative lesions, patients carrying TCFA lesions represent only one-third of LRP patients and are associated with a high risk of future events while patients carrying LRP-ThCFA and non-LRP lesions portend benign outcomes.Registration:URL:https://www.clinicaltrials.gov; Unique identifier: NCT02989740.

Fractional flow reserve is the current invasive gold standard for assessing the ischemic potential of an angiographically intermediate coronary stenosis. Procedural cost and time, the need for coronary vessel instrumentation, and the need to administer adenosine to achieve maximal hyperemia remain integral components of invasive fractional flow reserve. The number of new alternatives to fractional flow reserve has proliferated over the last ten years using techniques ranging from alternative pressure wire metrics to anatomic simulation via angiography or intravascular imaging. This review article provides a critical description of the currently available or under-development alternatives to fractional flow reserve with a special focus on the available evidence, pros, and cons for each with a view towards their clinical application in the near future for the functional assessment of coronary artery disease.

Purpose: To investigate the association of the degree of stent expansion, as assessed by optical coherence tomography (OCT), following stent implantation, and clinical outcomes in ST-segment elevation myocardial infarction (STEMI) patients. Methods: STEMI patients from the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and angioX) OCT study were selected; Clinical outcomes were collected through 1year. Stent expansion index is a minimum stent area (MSA) divided by average lumen area (average of proximal and distal reference lumen area). The following variables were measured: MSA (< 4.5mm2), dissection (> 200µm in width and < 5mm from stent segment), malapposition (> 200µm distance of stent from vessel wall), a thrombus (area > 5% of lumen area) were compared. Results: A total of 151 patients were included; after excluding patients with suboptimal OCT quality, the population with available OCT was classified into 2 groups: under–expanded < 90% (N = 72, 51%) and well–expanded ≥ 90% (N = 67, 49%). In the well–expanded group, a significant number of the proximal vessels had a lumen area < 4.5mm2 (16.1%, p < 0.001) and a greater thrombus burden within stent (56.7%, p = 0.042). The overall 30day and 1year major adverse cardiovascular event (MACE) rates were 5% and 6.1%, respectively. Conclusion: Irrespective of the degree of stent expansion, the OCT findings, in STEMI patients, and the MACE at 30days and one year follow up was low; further, well–expanded stents led to a more significant residual thrombotic burden within the stent but seemed to have insignificant clinical impact. Acknowledged stent optimization criteria, traditionally related to worse outcomes in stable patients, do not seem to be associated with worse outcomes in this STEMI population.

BACKGROUND/PURPOSE: To avoid long-term effects associated with permanent implants, bioresorbable vascular scaffolds were developed as they provide transient vessel support and disappear thereafter. The aim of the BIOSOLVE-II and -III studies was to assess the safety and performance of a magnesium based sirolimus-eluting scaffold; we report the clinical outcomes at 3 years, 2 years after scaffold resorption.METHODS/MATERIALS: BIOSOLVE-II and BIOSOLVE-III are international, prospective multi-center studies, including 184 patients with 189 de novo lesions and stable or unstable angina, or documented silent ischemia. Acute myocardial infarction, 3-vessel coronary artery disease and heavily calcified lesions were excluded. Antiplatelet therapy was recommended for 6-months.RESULTS: Patients were 65.5 ± 10.8 years old, and lesions were 12.1 ± 4.5 mm long and located in vessels with a diameter of 2.7 ± 0.4 mm. More than half of the lesions (56.5%) were type B2/C lesions. At 2 years, 92.5% (160/173) of patients were symptom-free and 91.5% (151/165) at 3 years; all the other patients had stable angina. At 3 years, target lesion failure occurred in 11 patients (6.3%), consisting of 4 cardiac deaths (2.3%), one target-vessel myocardial infarction (0.6%), and 6 clinically-driven target lesion revascularizations (3.4%). There was no definite or probable scaffold thrombosis.CONCLUSION: In a low-risk patient population, treatment with a sirolimus-eluting magnesium bioresorbable scaffold can be considered safe, in particular with no definite or probable scaffold thrombosis.ANNOTATED TABLE OF CONTENTS: BIOSOLVE-II- and III are prospective international, multi-center studies including 184 patients with de novo lesions. At 3 years, target lesion failure was 6.3%, consisting of 4 cardiac deaths (2.3%), one target-vessel myocardial infarction (0.6%), and 6 clinically-driven target lesion revascularizations (3.4%). There was no definite or probable scaffold thrombosis.

BACKGROUND Residual stent strut thrombosis after primary percutaneous coronary intervention (PCI), negatively affects myocardial perfusion, may increase stent thrombosis risk, and it is associated with neointima hyperplasia at follow-up. OBJECTIVES To study the effectiveness of any bivalirudin infusion versus unfractionated heparin (UFH) infusion in reducing residual stent strut thrombosis in patients with ST-elevation myocardial infarction (STEMI). METHODS Multi-vessel STEMI patients undergoing primary PCI and requiring staged intervention were selected among those randomly allocated to two different bivalirudin infusion regimens in the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and angioX) Treatment-Duration study. Those receiving heparin only were enrolled into a registry arm. Optical coherence tomography (OCT) of the infarct-related artery was performed at the end of primary PCI and 3-5 days thereafter during a staged intervention. The primary endpoint was the change in minimum flow area (ΔMinFA) defined as (stent area + incomplete stent apposition [ISA] area) - (intraluminal defect + tissue prolapsed area) between the index and staged PCI. RESULTS 123 patients in bivalirudin arm and 28 patients in the UFH arm were included. Mean stent area, percentage of malapposed struts, and mean percent thrombotic area were comparable after index or staged PCI. The ΔMinFA in the bivalirudin group was 0.25 versus 0.05 mm2 in the UFH group, which resulted in a between-group significant difference of 0.36 [95% CI: (0.05, 0.71); p = .02]. This was mostly related to a decrease in tissue protrusion in the bivalirudin group (p = .03). There was a trend towards more patients in the bivalirudin group who achieved a 5% difference in the percentage of OCT frames with the area >5% (p = .057). CONCLUSIONS The administration of bivalirudin after primary PCI significantly reduces residual stent strut thrombosis when compared to UFH. This observation should be considered hypothesis-generating since the heparin-treated patients were not randomly allocated.

This thesis sought to provide some novel insights on the complexity of the invasive assessment of ischaemic heart disease (IHD). Undoubtedly, focal coronary stenosis play a pivotal role in the genesis and prognosis of this entity. Furthermore, therapy guided by the functional assessment of such focal stenosis has shown to improve patient outcomes, as compared to therapy guided by their angiographic appearance alone. However, wealth of consistent data currently show how does this stenosiscentred diagnostic and therapeutical approach, relying only on the fractional flow reserve (FFR), is not perfect, since many patients with non-physiologically significant epicardial stenosis still suffer from angina and cardiovascular events, and conversely, a significant proportion of patients with FFR-significant stenosis do well at medium term. These leaves, consequently, room for further refinement. This thesis pursued to contribute to this refinement, and for these, followed a two-fold pathway. Firstly, it explored the diagnostic consequences of a simpler physiological approach, focused only on the pressure-lone assessment of focal stenosis under non-hyperaemic conditions. Secondly, it explored a more complex-yet comprehensive approach, that included, in addition to the FFR, the available indices to explore coronary microcirculation. In the following paragraphs, the salient findings of the different parts of the present thesis will be discussed in perspective.