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Background: Biolimus-eluting stents (BESs) with a biodegradable polymer in abluminal coating achieve more complete coverage at 9 months compared with sirolimus-eluting stents (SESs) with a durable polymer, as assessed by optical coherence tomography (OCT). Whether this advantage persists or augments after complete resorption of the polymer (>12 months) is unknown.Methods: The LEADERS trial compared the performance of BES with that of SES. Patients were randomly allocated to a sequential angiographic follow-up, including OCT in selected sites, at 9 and 24 months. Struts coverage was compared using Bayesian hierarchical models as the primary outcome for the OCT substudy.Results: Fifty-six patients (26 BES, 30 SES) were enrolled in the OCT substudy. Twenty-one patients (10 BES, 11 SES) agreed to perform a second OCT follow-up at 24 months. Eleven lesions and 12 stents were analyzed sequentially in the BES group (2,455 struts at 9 months, 2,131 struts at 24 months) and 11 lesions and 18 stents in the SES group (3,421 struts at 9 months, 4,170 struts at 24 months). The previously reported advantage of BES over SES in terms of better strut coverage at 9 months was followed by improvement in coverage of the SES, resulting in identical coverage in both BES and SES at 24 months: 1.5% versus 1.8% uncovered struts, difference -0.2%, 95% credibility interval, -3.2% to 2.6%, P = .84.Conclusions: More complete strut coverage of BES as compared with SES at 9 months was followed by improvement of coverage in SES between 9 and 24 months and a similar long-term coverage in both stent types at 24 months. [ABSTRACT FROM AUTHOR]

Background- Pathology studies on fatal cases of very late stent thrombosis have described incomplete neointimal coverage as common substrate, in some cases appearing at side-branch struts. Intravascular ultrasound studies have described the association between incomplete stent apposition (ISA) and stent thrombosis, but the mechanism explaining this association remains unclear. Whether the neointimal coverage of nonapposed side-branch and ISA struts is delayed with respect to well-apposed struts is unknown. Methods and Results- Optical coherence tomography studies from 178 stents implanted in 99 patients from 2 randomized trials were analyzed at 9 to 13 months of follow-up. The sample included 38 sirolimus-eluting, 33 biolimus-eluting, 57 everolimus-eluting, and 50 zotarolimus-eluting stents. Optical coherence tomography coverage of nonapposed side-branch and ISA struts was compared with well-apposed struts of the same stent by statistical pooled analysis with a random-effects model. A total of 34 120 struts were analyzed. The risk ratio of delayed coverage was 9.00 (95% confidence interval, 6.58 to 12.32) for nonapposed side-branch versus well-apposed struts, 9.10 (95% confidence interval, 7.34 to 11.28) for ISA versus well-apposed struts, and 1.73 (95% confidence interval, 1.34 to 2.23) for ISA versus nonapposed side-branch struts. Heterogeneity of the effect was observed in the comparison of ISA versus well-apposed struts (H=1.27; I(2)=38.40) but not in the other comparisons. Conclusions- Coverage of ISA and nonapposed side-branch struts is delayed with respect to well-apposed struts in drug-eluting stents, as assessed by optical coherence tomography. Clinical Trial Registration- http://www.clinicaltrials.gov. Unique identifier: NCT00389220, NCT00617084. [ABSTRACT FROM AUTHOR]

Background: The CTO-ARC (Chronic Total Occlusion Academic Research Consortium) recognized that a nonstandardized definition of chronic total occlusion (CTO) percutaneous coronary intervention approaches can bias the complications' attribution to each crossing strategy., Objectives: The study sought to describe the numbers, efficacy, and safety of each final CTO crossing strategy according to CTO-ARC recommendations., Methods: In this cross-sectional study, data were retrieved from the European Registry of Chronic Total Occlusions between 2021 and 2022., Results: Out of 8,673 patients, antegrade and retrograde approach were performed in 79.2% and 20.8% of cases, respectively. The antegrade approach included antegrade wiring and antegrade dissection and re-entry, both performed with or without retrograde contribution (antegrade wiring without retrograde contribution: n = 5,929 [68.4%]; antegrade wiring with retrograde contribution: n = 446 [5.1%]; antegrade dissection and re-entry without retrograde contribution: n = 353 [4.1%]; antegrade dissection and re-entry with retrograde contribution: n = 137 [1.6%]). The retrograde approach included retrograde wiring (n = 735 [8.4%]) and retrograde dissection and re-entry (n = 1,073 [12.4%]). Alternative antegrade crossing was associated with lower technical success (70% vs 86% vs 93.1%, respectively; P < 0.001) and higher complication rates (4.6% vs 2.9% vs 1%, respectively; P < 0.001) as compared with retrograde and true antegrade crossing. However, alternative antegrade crossing was applied mostly as a rescue strategy (96.1%)., Conclusions: The application of CTO-ARC definitions allowed the reclassification of 6.7% of procedures as alternative antegrade crossing with retrograde or antegrade contribution which showed higher MACCE and lower technical success rates, as compared with true antegrade and retrograde crossing., Competing Interests: Funding Support and Author Disclosures Dr Bufe has received speaker honoraria from Biotronik and Shockwave Medical. Dr Pyxaras has received consulting/speaker/proctorship honoraria from Abiomed, AstraZeneca, Asahi Intecc, Biotronik, Boston Scientific, and Terumo. Dr Ladwiniec has received consulting/speaker/proctoring honoraria from Abbott, Biotronik, Boston Scientific, Cordis, Shockwave Medical, and SMT. Dr Werner has received speaker honoraria from Abbott, Asahi Intecc, OrbusNeich, Philips, Siemens, and Terumo. Dr Mashayekhi has received consulting/speaker/proctoring honoraria from Abbott, Abiomed, Asahi Intecc, AstraZeneca, Biotronik, Boston Scientific, Cardinal Health, Daiichi-Sankyo, Medtronic, OrbusNeich, Shockwave Medical, Teleflex, and Terumo. Dr Ayoub has received consultant/proctor honoraria from Boston Scientific, Teleflex, Asahi Intecc, Cordis, Terumo, and SIS Medical. Dr Goktekin has received consulting/speaker/proctoring honoraria from Boston Scientific, Medtronik, MicroPort, and Asahi Inc. Dr Agostoni has received consulting honoraria from Abbott, Boston Scientific, Cordis, iVascular, Medtronic, Neovasc, Seven Sons, Teleflex, and Terumo. Dr Diletti has received consultant/proctoring honoraria from Asahi Intecc, Terumo, IMDS, Boston Scientific, Teleflex, and Philips. Dr Rathore has received honoraria for speaker and proctoring from Abbott Vascular and Translumina Therapeutics. Dr Bozinovic has served as a speaker or proctor and/or received honoraria from Orbus Neich and Medtronic. Dr Galassi has received consulting/speaker honoraria from Asahi Intecc and Ivascular. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: This study aimed to describe and analyze the rate of clot migration of vessel thrombosis to distal segments in patients with acute ischemic stroke (AIS) who received intravenous thrombolysis (IVT) with tenecteplase (TNK) and alteplase (ALT) before mechanical thrombectomy (MT). In addition, we aimed to determine the relationship between thrombus migration and functional prognosis., Methods: This study followed the STROBE reporting guidelines. We performed a retrospective analysis of a series of patients from November 2017 to April 2023 with an AIS with thrombosis on CT imaging, treated with IVT (TNK or ALT, split into two distinct groups) prior to mechanical thrombectomy., Results: Two hundred and fifty-six patients with large vessel occlusion (LVO) were included. Ninety-six had received TNK. One hundred and sixty had received ALT. Of the 96 TNK patients, 25 experienced either complete recanalization ( n  = 3) or thrombus migration ( n  = 22). Of the 160 ALT patients, 20 experienced either complete recanalization ( n  = 6) or thrombus migration ( n  = 14). The difference being statistically substantial for the thrombus migration rate (OR = 3.61, 95% confidence interval: 1.63; 7.98). Migration to an irretrievable very distal segment occurred in four (4%) patients with TNK and in three patients (2%) with ALT ( p  > 0.05). Thrombus migration was not significantly associated to a different functional prognosis, measured through Rankin scale after 3 months (OR = 0.44, 95% confidence interval: 0.17; 1.12)., Conclusion: The use of TNK over ALT as a fibrinolytic agent is associated with a higher thrombus migration rate. The migration of thrombi to distal segments, which are theoretically less accessible for mechanical thrombectomy, did not result in worse clinical outcomes., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Current polymer-based drug-eluting stents (DESs) have fundamental issues about inflammation and delayed re-endothelializaton of the vessel wall. Substance-P (SP), which plays an important role in inflammation and endothelial cells, has not yet been applied to coronary stents. Therefore, this study compares poly lactic-co-glycolic acid (PLGA)-based everolimus-eluting stents (PLGA-EESs) versus 2-methacryloyloxyethyl phosphorylcholine (MPC)-based SP-eluting stents (MPC-SPs) in in-vitro and in-vivo models., Methods: The morphology of the stent surface and peptide/drug release kinetics from stents were evaluated. The in-vitro proliferative effect of SP released from MPC-SP is evaluated using human umbilical vein endothelial cell. Finally, the safety and efficacy of the stent are evaluated after inserting it into a pig's coronary artery., Results: Similar to PLGA-EES, MPC-SP had a uniform surface morphology with very thin coating layer thickness (2.074 μm). MPC-SP showed sustained drug release of SP for over 2 weeks. Endothelial cell proliferation was significantly increased in groups treated with SP (n = 3) compared with the control (n = 3) and those with everolimus (n = 3) (SP: 118.9 ± 7.61% vs. everolimus: 64.3 ± 12.37% vs. the control: 100 ± 6.64%, p < 0.05). In the animal study, the percent stenosis was higher in MPC-SP group (n = 7) compared to PLGA-EES group (n = 7) (MPC-SP: 28.6 ± 10.7% vs. PLGA-EES: 16.7 ± 6.3%, p < 0.05). MPC-SP group showed, however, lower inflammation (MPC-SP: 0.3 ± 0.26 vs. PLGA-EES: 1.2 ± 0.48, p < 0.05) and fibrin deposition (MPC-SP: 1.0 ± 0.73 vs. PLGA-EES: 1.5 ± 0.59, p < 0.05) around the stent strut. MPC-SP showed more increased expression of cluster of differentiation 31, suggesting enhanced re-endothelialization., Conclusion: Compared to PLGA-EES, MPC-SP demonstrated more decreased inflammation of the vascular wall and enhanced re-endothelialization and stent coverage. Hence, MPC-SP has the potential therapeutic benefits for the treatment of coronary artery disease by solving limitations of currently available DESs., (© 2023. Korean Tissue Engineering and Regenerative Medicine Society.)

Objectives: Confirming the prognostic value of global QFR and evaluating the long-term prognosis of QFR-concordant therapy in stable coronary artery disease., Background: Wire-based functional evaluation of coronary disease is linked to patient's prognosis. Quantitative Flow Ratio (QFR) is a newer index of computational physiology, linked to clinical outcomes and prognosis at 1 year follow-up. Long-term prognosis of QFR-concordant revascularization in stable coronary artery disease is however unknown hitherto., Methods: Consecutive patients with stable coronary disease undergoing coronary angiography were included. Centralized and blinded QFR analysis of three coronary territories was performed. Three vessel QFR (3vQFR) was defined as the sum of the basal QFR of each coronary territory. QFR-concordant revascularization was met if all significant lesions (QFR ≤ 0.80) were revascularized and all non-significant lesions (QFR > 0.80) were not; otherwise, the case was defined as QFR-discordant revascularization. Patient-oriented composite end-point (POCE) of cardiac death, myocardial infarction and unscheduled revascularization was the primary endpoint., Results: A total of 803 patients from six high-volume centers were included. Canadian Cardiovascular Society (CCS) class II angina was the most frequent (48.9%) clinical presentation. Median of follow-up was 68.8 months. 3vQFR was an independent predictor of POCE (HR 1.79 CI95% 1.01-3.18), with 2.75 as optimal cut-off value, irrespective of the therapy received. QFR-discordant revascularization (QFR+/Revascularization- or QFR-/Revascularization+) was an independent predictor of POCE in multivariate analysis (HR 1.65, CI 95% 1.03-2.64)., Conclusion: Global burden of epicardial coronary atherosclerosis, as evaluated by 3vQFR, as well as QFR-discordant therapy are independent predictors of adverse clinical outcome at long-term follow-up in stable coronary artery disease., Competing Interests: Declaration of Competing Interest Dr. Carlos Cortés is beneficiary of a Contrato Rio Hortega grant from the Instituto de Salud Carlos III with code CM22/00168., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Knowledge in the field of bifurcation lesions and chronic total occlusions (CTOs) has progressively improved over the past 20 years. Therefore, the European Bifurcation Club and the EuroCTO Club have decided to write a joint consensus statement to share general knowledge and practical approaches in this complex field. When percutaneously treating CTOs, bifurcation lesions with relevant side branches (SBs) are found in approximately one-third of cases (35% at the proximal cap, 38% at the distal cap, and 27% within the CTO body). Occlusion of a relevant SB is not rare and has been shown to be associated with procedural complications and adverse outcomes. Simple bifurcation rules are very useful to prevent SB occlusion, and provisional SB stenting is the recommended approach in the majority of cases: protect the SB as soon as possible by wiring it, respect the fractal anatomy of the bifurcation by using the 3-diameter rule, and avoid using dissection and re-entry techniques. A systematic 2-stent approach can be used if needed or sometimes to connect both branches of the bifurcation. The retrograde approach can be very useful to save a relevant SB, especially in the case of a bifurcation at the distal cap or within the CTO body. Intravascular ultrasound is also a very important tool to address the difficulties with bifurcations at the proximal or distal cap and sometimes also within the CTO segment. Double-lumen microcatheters and angulated microcatheters are crucial tools to resolve access difficulties to the SB or the main branch., Competing Interests: Funding Support and Author Disclosures Dr Lefèvre has received minor fees from Abbott, Boston Scientific, and Terumo. Dr Pan has received minor lecture fees from Abbott, Asahi Intecc, Terumo, and Boston Scientific. Dr Stankovic has received speaker fees from Medtronic, Abbott, Boston Scientific, and Terumo. Dr Ojeda has received consulting fees from Medtronic and Edwards Lifesciences. Dr Boudou has received consulting honoraria for Asahi Intecc, Terumo, and Boston Scientific. Dr Brilakis has received consulting and speaker honoraria from Abbott Vascular, the American Heart Association (associate editor, Circulation), Amgen, Asahi Intecc, Biotronik, Boston Scientific, the Cardiovascular Innovations Foundation (Board of Directors), Cardiovascular Systems, Elsevier, GE Healthcare, IMDS, Medicure, Medtronic, Siemens, and Teleflex; has received research support from Boston Scientific and GE Healthcare; is an owner of Hippocrates; and is a shareholder in MHI Ventures, Cleerly Health, and Stallion Medical. Dr Garbo has received proctorship and consulting fees from Boston Scientific, Asahi Intecc, Philips, Terumo, Teleflex, and IMDS. Dr Di Mario has received research grants to his institution from Abbott, Amgen, Boston Scientific, Chiesi, Daiichi Sankyo, Edwards Lifesciences, Idorsia, Medtronic, Shockwave, and Volcano. Dr Hildick-Smith has received research funds and speaker fees from Medtronic. Dr Mashayekhi has received consulting, speaker, and proctoring honoraria from Abbott Vascular, Abiomed, Asahi Intecc, AstraZeneca, Biotronik, Boston Scientific, Cardinal Health, Daiichi Sankyo, Medtronic, Shockwave Medical, Teleflex, and Terumo. Dr Werner has received speaker fees from Asahi Intecc, Orbus-Neich, Philips-Volcano, Siemens, Shockwave Medical, and Terumo. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Accurate and efficient 3-dimension (3D) reconstruction of coronary stents in intravascular imaging of optical coherence tomography (OCT) or intravascular ultrasound (IVUS) is important for optimization of complex percutaneous coronary interventions (PCI). Deep learning has been used to address this technical challenge. However, manual annotation of stent is strenuous, especially for IVUS images. To this end, we aim to explore whether the OCT and IVUS images can assist each other in stent 3D reconstruction when one of them is lack of labeled dataset., Methods: We firstly performed cross-modal translation between OCT and IVUS images, where disentangled representation was employed to generate synthetic images with good stent consistency. The reciprocal assistance of OCT and IVUS in stent 3D reconstruction was then conducted by applying unsupervised and semi-supervised learning with the aid of synthetic images. Stent consistency in synthetic images and reciprocal effectiveness in stent 3D reconstruction were quantitatively assessed by F1-Score (FS) on two datasets: OCT-High Definition IVUS (HD IVUS) and OCT-Conventional IVUS (IVUS)., Results: The employment of disentangled representation achieved higher stent consistency in synthetic images (OCT to HD IVUS: FS=0.789 vs 0.684; HD IVUS to OCT: FS=0.766 vs 0.682; OCT to IVUS: FS=0.806 vs 0.664; IVUS to OCT: FS=0.724 vs 0.673). For stent 3D reconstruction, the assistance from synthetic images significantly promoted unsupervised adaptation across modalities (OCT to HD IVUS: FS=0.776 vs 0.109; HD IVUS to OCT: FS=0.826 vs 0.125; OCT to IVUS: FS=0.782 vs 0.068; IVUS to OCT: FS=0.815 vs 0.123), and improved performance in semi-supervised learning, especially when only limited labeled data was available., Conclusion: The intravascular images of OCT and IVUS can provide reciprocal assistance to each other in stent 3D reconstruction by cross-modal translation, where the stent consistency in synthetic images was maintained by disentangled representation., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Shengxian Tu reports a relationship with Pulse Medical that includes: consulting or advisory and funding grants. S Tu is the co-founder of Pulse Medical., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Percutaneous coronary intervention has been a standard treatment strategy for patients with coronary artery disease with continuous ebullient progress in technology and techniques. The application of artificial intelligence and deep learning in particular is currently boosting the development of interventional solutions, improving the efficiency and objectivity of diagnosis and treatment. The ever-growing amount of data and computing power together with cutting-edge algorithms pave the way for the integration of deep learning into clinical practice, which has revolutionized the interventional workflow in imaging processing, interpretation, and navigation. This review discusses the development of deep learning algorithms and their corresponding evaluation metrics together with their clinical applications. Advanced deep learning algorithms create new opportunities for precise diagnosis and tailored treatment with a high degree of automation, reduced radiation, and enhanced risk stratification. Generalization, interpretability, and regulatory issues are remaining challenges that need to be addressed through joint efforts from multidisciplinary community., Competing Interests: This study was supported by the Natural Science Foundation of China (82020108015 and 81871460). Dr Tu reported research grants and consultancy from Pulse Medical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

Background: Coronary flow reserve (CFR) has prognostic value in patients with coronary artery disease. However, its measurement is complex, and automatic methods for CFR computation are scarcely available. We developed an automatic method for CFR computation based on coronary angiography and assessed its feasibility., Methods: Coronary angiographies from the Corelab database were annotated by experienced analysts. A convolutional neural network (CNN) model was trained for automatic segmentation of the main coronary arteries during contrast injection. The segmentation performance was evaluated using 5-fold cross-validation. Subsequently, the CNN model was implemented into a prototype software package for automatic computation of the CFR (CFRauto) and applied on a different sample of patients with angiographies performed both at rest and during maximal hyperemia, to assess the feasibility of CFRauto and its agreement with the manual computational method based on frame count (CFRmanual)., Results: Altogether, 137,126 images of 5913 angiographic runs from 2407 patients were used to develop and evaluate the CNN model. Good segmentation performance was observed. CFRauto was successfully computed in 136 out of 149 vessels (91.3%). The average analysis time to derive CFRauto was 18.1 ± 10.3 s per vessel. Moderate correlation (r = 0.51, p < 0.001) was observed between CFRauto and CFRmanual, with a mean difference of 0.12 ± 0.53., Conclusions: Automatic computation of the CFR based on coronary angiography is feasible. This method might facilitate wider adoption of coronary physiology in the catheterization laboratory to assess microcirculatory function.

Percutaneous coronary intervention (PCI) of chronic total occlusions (CTO) in coronary bifurcation lesions (CBL) is undergoing substantial technical progress and standardization, paralleling the evolution of dedicated devices, tools, and techniques. A standard consensus to classify CTO-CBL might be instrumental to homogenize data collection and description of procedures for scientific and educational purposes. The Medina-CTO classification replicates the classical three digits in Medina classification for bifurcations, representing the proximal main vessel, distal main vessel, and side branch, respectively. Each digit can take a value of 1 if it concerns atherosclerosis and is anatomically stenosed, or 0 if it is not. In addition, the occluded segment(s) of the bifurcation are noted by a subscript, which describes key interventional features of the cap: t (tapered), b (blunt), or a (ambiguous). This approach results in 56 basic categories that can be grouped by means of different elements, depending on the specific needs of each study. Medina-CTO classification, consisting of adding a subscript describing the basic cap characteristics to the totally occluded segment(s) of the standard Medina triplet, might be a useful methodological tool to standardize percutaneous intervention of bifurcational CTO lesions, with interesting scientific and educational applications.

Background: Assessment of collaterals physiology in chronic total occlusions (CTO) currently requires dedicated devices, adds complexity, and increases the cost of the intervention. This study sought to derive collaterals physiology from flow velocity changes (ΔV) in donor arteries, calculated with artificial intelligence- aided angiography., Methods: Angiographies with successful percutaneous coronary intervention (PCI) in 2 centers were retro- spectively analyzed. CTO collaterals were angiographically evaluated according to Rentrop and collateral connections (CC) classifications. Flow velocities in the primary and secondary collateral donor arteries (PCDA, SCDA) were automatically computed pre and post PCI, based on a novel deep-learning model to extract the length/time curve of the coronary filling in angiography. Parameters of collaterals physiology, Δcollateral-flow (Δfcoll) and Δcollateral-flow-index (ΔCFI), were derived from the ΔV pre-post., Results: The analysis was feasible in 105 out of 130 patients. Flow velocity in the PCDA significantly decreased after CTO-PCI, proportionally to the angiographic collateral grading (Rentrop 1: 0.02 ± 0.01 m/s; Rentrop 2: 0.04 ± 0.01 m/s; Rentrop 3: 0.07 ± 0.02 m/s; p < 0.001; CC0: 0.01 ± 0.01 m/s; CC1: 0.04 ± ± 0.02 m/s; CC2: 0.06 ± 0.02 m/s; p < 0.001). Δfcoll and ΔCFI paralleled ΔV. SCDA also showed a greater reduction in flow velocity if its collateral channels were CC1 vs. CC0 (0.03 ± 0.01 vs. 0.01 ± 0.01 m/s; p < 0.001). For each individual patient, ΔV was more pronounced in the PCDA than in the SCDA., Conclusions: Automatic assessment of collaterals physiology in CTO is feasible, based on a deeplearning model analyzing the filling of the donor vessels in angiography. The changes in collateral flow with this novel method are quantitatively proportional to the angiographic grading of the collaterals.

Background: The aim of this study was to describe the mechanism of subintimal shift (SIS), standardise diagnostic criteria and sensitise the interventional community to this phenomenon. The treatment of chronic total occlusions (CTO) by means of percutaneous coronary intervention (PCI) is complicated by bifurcation lesions involved in the CTO segment or adjacent to it. Extraplaque expansion of intracoronary devices during CTO PCI may extend the dissection plane over the bifurcation with the consequential side or main branch compression by an intimo-medial flap. This phenomenon is hereby described for the first time and named subintimal shift., Methods: Experienced CTO operators from 3 international high volume centers for CTO PCI retrospectively searched their personal records for paradigmatic cases of SIS, summarising key features and proposing diagnostic criteria., Results: The series comprised 7 demonstrative cases, illustrating SIS by intravascular imaging (2 cases) or indirect angiographic signs during CTO PCI (5 cases). Five cases were triggered by stent expansion, 1 by balloon inflation and 1 case was aborted after angiographic warning signs. In 4 cases, SIS resulted in total occlusion of a branch, refractory to ballooning whenever attempted. Four cases required bailout intervention and in 2 cases the branch was left occluded, resulting in a rise of cardiac markers., Conclusions: Subintimal shift is a noteworthy complication in CTO bifurcations, potentially resulting in occlusion of the relevant side or even the main branch. Intracoronary imaging prior to stenting is recommended to understand the tissue planes. Some counterintuitive peculiarities of this phenomenon, like its refractoriness to ballooning, must be known by CTO operators for its efficient resolution.

Background: The relation between cardiac motion artefact (CMA) in optical coherence tomography (OCT) and the phases of cardiac cycle is unclear., Methods: Optical coherence tomography pullbacks containing metallic stents were co-registered with angiography and retrospectively analyzed. The beginning of three phases, namely ejection, rapid-inflow and diastasis, was identified in angiography. Rotation, shortening, elongation and repetition were qualitatively labelled as CMA artefacts. Platforms with coaxial longitudinal connectors (ML8 and Magmaris) entered a quantitative sub-study, consisting of measuring the length of their connector at the beginning of each phase., Results: A total of 261 stents (127 patients) were analyzed, including 105 stents for quantitative sub-study. CMA was detected in 61 (23.4%) stents: rotation in 6 (2.3%), shortening in 50 (19.2%), elongation in 51 (19.5%) and repetition in 12 (4.6%). Shortening was always observed during ejection phase, while elongation and repetition were always observed during rapid-inflow. Rotation occurred in both ejection and rapid-inflow phases, while no artefact was reported during diastasis. Longitudinal connectors measured in early ejection phase and in early rapid-inflow phase were shorter and longer, respectively, than those measured in diastasis, irrespective of the presence of CMA in the qualitative assessment., Conclusions: Cardiac motion artefact is prevalent in OCT studies, but shortening and elongation of vascular structures occur during early ejection and during early rapid-inflow, respectively, to a greater or lesser extent in all cases. Diastasis is free of CMA and hence the period in which longitudinal measurements can be more accurately quantified.

Background: Investigating the prognostic value of the Murray law-based quantitative flow ratio (μQFR) on the clinical outcome after treatment of in-stent restenosis (ISR) with a drug-coated balloon (DCB)., Methods: Patients participating in a previous randomized clinical trial for DCB-ISR were post-hoc analyzed. The primary endpoint was vessel-oriented composite endpoint (VOCE), defined as cardiac death, target vessel-related myocardial infarction, and ischemia-driven target vessel revascularization. μQFRs at baseline and after DCB angioplasty was calculated, and its prognostic value as a predictor of VOCE was explored in Cox regression., Results: A total of 169 lesions in 169 patients were analyzed. At 1-year follow-up, 20 VOCEs occurred in 20 patients. Receiver-operating characteristic curve analysis identified a post-procedural μQFR of ≤ 0.89 as the best cut-off to predict VOCE (area under curve [AUC]: 0.74; 95% confidence interval [CI]: 0.67-0.80; p < 0.001), superior to post-procedural in-stent percent diameter stenosis, which reported an AUC of 0.61 (95% CI: 0.53-0.68; p = 0.18). Post-procedural μQFR was significantly lower in patients with VOCE compared with those without (0.88 [interquartile range: 0.79-0.94] vs. 0.96 [interquartile range: 0.91-0.98], respectively; p < 0.001). After correction for potential confounders, post-procedural μQFR ≤ 0.89 was associated with a 6-fold higher risk of VOCE than lesions with μQFR > 0.89 (hazard ratio: 5.94; 95% CI: 2.33-15.09; p < 0.001)., Conclusions: Post-procedural μQFR may become a promising predictor of clinical outcome after treatment of DES-ISR lesions by DCB angioplasty.

Background: High-strain spots in coronary arteries are associated with plaque vulnerability and predict future events. Artificial intelligence currently enables the calculation of radial wall strain (RWS) from coronary angiography (RWS Angio ). This study aimed to determine the agreement between novel RWS Angio and RWS derived from optical coherence tomography (OCT) followed by finite element analysis, as the established reference standard (RWS OCT )., Methods: All lesions from a previous OCT study were enrolled. OCT was automatically coregistered with angiography. RWS Angio was computed as the relative luminal deformation throughout the cardiac cycle, whereas RWS OCT was analyzed using finite element analysis on OCT cross-sections at 1-mm intervals. The luminal deformation in the direction of minimal lumen diameter was used to derive RWS OCT , using the same definition as RWS Angio . The maximal RWS OCT and RWS Angio at healthy segments adjacent to the interrogated lesion were also analyzed., Results: Finite element analysis was performed in 578 OCT cross-sections from 45 lesions stemming from 36 patients. RWS Angio showed good correlation and agreement with RWS OCT ( r = 0.91; P < .001; Lin coefficient = 0.85). RWS Angio in atherosclerotic segments was significantly higher than that in healthy segments (12.6% [11.0, 16.0] vs 4.5% [2.9, 5.5], P < .001). The intraclass correlation coefficients for intra- and interobserver variability in repeated RWS Angio analysis were 0.92 (95% CI, 0.87-0.95) and 0.88 (95% CI, 0.81-0.92), respectively. The mean analysis time of RWS OCT and RWS Angio for each lesion was 95.0 ± 41.1 and 0.9 ± 0.1 minutes, respectively., Conclusions: Radial wall strain from coronary angiography can be rapidly and easily computed solely from angiography, showing excellent agreement with strain derived from coregistered OCT. This novel and simple method might provide a cost-effective biomechanical assessment in large populations., (© 2022 The Author(s).)

The field of Autoimmune Neurology is expanding rapidly, with new neural antibodies being identified each year. However, these disorders remain rare. Deciding when to test for these antibodies, when and what samples are to be obtained, how to handle and study them correctly, and how to interpret test results, is complex. In this article we review current diagnostic techniques and provide a comprehensive explanation on the study of these patients, in an effort to help with correct diagnosis minimizing false positive and false negative results. We also propose routine storage of samples and referral of certain cases to specialized research laboratories., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Fernández-Fournier, Lacruz, Nozal, Chico, Tallón Barranco, Otero-Ortega, Corral and Carrasco.)

Background: The lipid-to-cap ratio (LCR) and thin-cap fibroatheroma (TCFA) derived from optical coherence tomography (OCT) are indicative of plaque vulnerability., Aims: We aimed to explore the association of a novel method to estimate radial wall strain (RWS) from angiography with plaque composition and features of vulnerability assessed by OCT., Methods: Anonymised data from patients with intermediate stenosis who underwent coronary angiography (CAG) and OCT were analysed in a core laboratory. Angiography-derived RWS max was computed as the maximum deformation of lumen diameter throughout the cardiac cycle, expressed as a percentage of the largest lumen diameter. The LCR and TCFA were automatically determined on OCT images by a recently validated algorithm based on artificial intelligence., Results: OCT and CAG images from 114 patients (124 vessels) were analysed. The average time for the analysis of RWS max was 57 (39-82) seconds. The RWS max in the interrogated plaques was 12% (10-15%) and correlated positively with the LCR (r=0.584; p<0.001) and lipidic plaque burden (r=0.411; p<0.001), and negatively with fibrous cap thickness (r= -0.439; p<0.001). An RWS max >12% was an angiographic predictor for an LCR >0.33 (area under the curve [AUC]=0.86, 95% confidence interval [CI]: 0.78-0.91; p<0.001) and TCFA (AUC=0.72, 95% CI: 0.63-0.80; p<0.001). Lesions with RWS max >12% had a higher prevalence of TCFA (22.0% versus 1.5%; p<0.001), thinner fibrous cap thickness (71 μm versus 101 μm; p<0.001), larger lipidic plaque burden (23.3% versus 15.4%; p<0.001), and higher maximum LCR (0.41 versus 0.18; p<0.001) compared to lesions with RWS max ≤12%., Conclusions: Angiography-derived RWS was significantly correlated with plaque composition and known OCT features of plaque vulnerability in patients with intermediate coronary stenosis.

Background: Artificial intelligence enables simultaneous evaluation of plaque morphology and computational physiology from optical coherence tomography (OCT)., Objectives: This study sought to appraise the predictive value of major adverse cardiovascular events (MACE) by combined plaque morphology and computational physiology., Methods: A total of 604 patients with acute coronary syndrome who underwent OCT imaging in ≥1 nonculprit vessel during index coronary angiography were retrospectively enrolled. A novel morphologic index, named the lipid-to-cap ratio (LCR), and a functional parameter to evaluate the physiologic significance of coronary stenosis from OCT, namely, the optical flow ratio (OFR), were calculated from OCT, together with classical morphologic parameters, like thin-cap fibroatheroma (TCFA) and minimal lumen area., Results: The 2-year cumulative incidence of a composite of nonculprit vessel-related cardiac death, cardiac arrest, acute myocardial infarction, and ischemia-driven revascularization (NCV-MACE) at 2 years was 4.3%. Both LCR (area under the curve [AUC]: 0.826; 95% CI: 0.793-0.855) and OFR (AUC: 0.838; 95% CI: 0.806-0.866) were superior to minimal lumen area (AUC: 0.618; 95% CI: 0.578-0.657) in predicting NCV-MACE at 2 years. Patients with both an LCR of >0.33 and an OFR of ≤0.84 had significantly higher risk of NCV-MACE at 2 years than patients in whom at least 1 of these 2 parameters was normal (HR: 42.73; 95% CI: 12.80-142.60; P < 0.001). The combination of thin-cap fibroatheroma and OFR also identified patients at higher risk of future events (HR: 6.58; 95% CI: 2.83-15.33; P < 0.001)., Conclusions: The combination of LCR with OFR permits the identification of a subgroup of patients with 43-fold higher risk of recurrent cardiovascular events in the nonculprit vessels after acute coronary syndrome., Competing Interests: This study was supported by the Natural Science Foundation of China (82020108015 and 81871460 to Dr Tu, 81827806 to Dr Yu, 81722025 and 82061130223 to Dr Jia) and by the National Key Research and Development Program of China (to Dr Tu, 2016YFC1301100 to Dr Yu). Dr Wijns would like to acknowledge the support by Science Foundation Ireland (RSF1413). Dr Tu is a consultant of Pulse Medical and has received research grants from Pulse Medical Imaging Technology. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2022 The Authors.)

Background: The agreement between single-projection Murray-based quantitative flow ratio (mQFR) and conventional three-dimensional quantitative flow ratio (3D-QFR) has not been reported hitherto., Methods: Patients from a multinational database were randomly selected for the study of agreement, according to sample size calculation. Both conventional 3D-QFR and mQFR were analyzed for all available arteries at a central corelab by independent analysts, blinded to each other's results., Results: Ninety-eight coronary arteries from 35 patients were finally analyzed. Median 3D-QFR was 0.82 (interquartile range 0.78-0.87). The intraclass correlation coefficient for the absolute agreement between 3D-QFR and mQFR was 0.996 (95% confidence interval [CI]: 0.993-0.997); Lin's coefficient 0.996 (95% CI: 0.993-0.997), without constant or proportional bias (intercept = 0 and slope = 1 in orthogonal regression). As dichotomous variable, there was absolute agreement between mQFR and 3D-QFR, resulting in no single false positive or negative. Kappa index was 1 and the diagnostic accuracy 100%., Conclusions: mQFR using a single angiographic projection showed almost perfect agreement with standard 3D-QFR. These results encourage the interchangeable use of mQFR and 3D-QFR, which can be interesting to improve QFR feasibility in retrospective studies, wherein appropriate double angiographic projections might be challenging to obtain.

Introduction: Cyclic plaque structural stress has been hypothesized as a mechanism for plaque fatigue and eventually plaque rupture. A novel approach to derive cyclic plaque stress in vivo from optical coherence tomography (OCT) is hereby developed. Materials and Methods: All intermediate lesions from a previous OCT study were enrolled. OCT cross-sections at representative positions within each lesion were selected for plaque stress analysis. Detailed plaque morphology, including plaque composition, lumen and internal elastic lamina contours, were automatically delineated. OCT-derived vessel and plaque morphology were included in a 2-dimensional finite element analysis, loaded with patient-specific intracoronary pressure tracing data, to calculate the changes in plaque structural stress (ΔPSS) on vessel wall over the cardiac cycle. Results: A total of 50 lesions from 41 vessels were analyzed. A significant ΔPSS gradient was observed across the plaque, being maximal at the proximal shoulder (45.7 [32.3, 78.6] kPa), intermediate at minimal lumen area (MLA) (39.0 [30.8, 69.1] kPa) and minimal at the distal shoulder (35.1 [28.2, 72.3] kPa; p = 0.046). The presence of lipidic plaques were observed in 82% of the diseased segments. Larger relative lumen deformation and ΔPSS were observed in diseased segments, compared with normal segments (percent diameter change: 8.2 ± 4.2% vs. 6.3 ± 2.3%, p = 0.04; ΔPSS: 59.3 ± 48.2 kPa vs. 27.5 ± 8.2 kPa, p < 0.001). ΔPSS was positively correlated with plaque burden ( r = 0.37, p < 0.001) and negatively correlated with fibrous cap thickness ( r = -0.25, p = 0.004). Conclusions: ΔPSS provides a feasible method for assessing plaque biomechanics in vivo from OCT images, consistent with previous biomechanical and clinical studies based on different methodologies. Larger ΔPSS at proximal shoulder and MLA indicates the critical sites for future biomechanical assessment., Competing Interests: WW reports research grants and honoraria from MicroPort, medical advisor of Rede Optimus Research and co-founder of Argonauts, an innovation facilitator. ST reports research grants and consultancy from Pulse medical imaging technology. PS reports personal fees from Sino Medical Science Technology, Philips/Volcano, Xeltis, HeartFlow, and SMT, outside the submitted work. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Huang, Yang, Gutiérrez-Chico, Xu, Wu, Wang, Lv, Lai, Liu, Onuma, Tang, Serruys, Wijns and Tu.)

This study sought to evaluate a novel approach for automatic coregistration of optical coherence tomography (OCT) and coronary angiography. Lumen diameters and side branches from both coronary angiography and OCT were used to create 2 feature sets. Subsequently, a 2-step coregistration approach was performed on the feature sets for matching of each OCT cross section on the angiographic centerline. For validation, all side branches with ≥1.0 mm diameter were identified and used as paired fiduciary landmarks. Geographical error was defined as the distance between the automatically coregistered and the true-paired landmarks. Altogether 212 vessels from 181 patients were analyzed. Mismatch of coronary angiography and OCT occurred in 64 of 1,530 reference landmarks. Median geographical error was 0.32 (interquartile range: 0.00-0.56) mm. The mean time for coregistration was 20.69 ± 1.07 seconds. In conclusion, fast and automatic coregistration of OCT and angiography using a single standard angiographic loop is feasible and accurate., Competing Interests: This study is supported by the National Key Research and Development Program of China and the Natural Science Foundation of China (grants 81871460 and 82020108015). Dr Tu has received research support from Pulse Medical Imaging Technology. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2021 The Authors.)

Background: The ability of optical coherence tomography (OCT) to identify specific types of stent has never been systematically studied., Aims: The aim of this study was to test the accuracy of OCT imaging to identify patterns of stent platform and subsequently identify the type of stent implanted., Methods: Consecutive patients from six international centres were retrospectively screened, searching for OCT studies with metallic stents or scaffolds. The sample was analysed by two blinded operators, applying a dedicated protocol in four steps to identify the type of stent: 1) 3D and automatic strut detection (ASD), 2) 3D tissue view, 3) longitudinal view with ASD, 4) mode "stent only" and ASD., Results: A series of 212 patients underwent OCT in the study centres, finding 294 metallic stents or scaffolds in 146 patients. The protocol correctly identified 285 stents (96.9%, kappa 0.965), with excellent interobserver agreement (kappa 0.988). The performance tended to be better in recently implanted stents (kappa 0.993) than in stents implanted ≥3 months before (kappa 0.915), and in pullback speed 18 mm/s as compared with 36 mm/s (kappa 0.969 vs 0.940, respectively)., Conclusions: The type of stent platform can be accurately identified in OCT by trained analysts following a dedicated protocol, combining 3D-OCT, ASD and longitudinal view. This might be clinically helpful in scenarios of device failure and for the quantification of apposition. The blinding of analysts in OCT studies should be revisited.

Background: Intravascular optical coherence tomography (IVOCT) enables detailed plaque characterisation in vivo, but visual assessment is time-consuming and subjective., Aims: This study aimed to develop and validate an automatic framework for IVOCT plaque characterisation using artificial intelligence (AI)., Methods: IVOCT pullbacks from five international centres were analysed in a core lab, annotating basic plaque components, inflammatory markers and other structures. A deep convolutional network with encoding-decoding architecture and pseudo-3D input was developed and trained using hybrid loss. The proposed network was integrated into commercial software to be externally validated on additional IVOCT pullbacks from three international core labs, taking the consensus among core labs as reference., Results: Annotated images from 509 pullbacks (391 patients) were divided into 10,517 and 1,156 cross-sections for the training and testing data sets, respectively. The Dice coefficient of the model was 0.906 for fibrous plaque, 0.848 for calcium and 0.772 for lipid in the testing data set. Excellent agreement in plaque burden quantification was observed between the model and manual measurements (R2=0.98). In the external validation, the software correctly identified 518 out of 598 plaque regions from 300 IVOCT cross-sections, with a diagnostic accuracy of 97.6% (95% CI: 93.4-99.3%) in fibrous plaque, 90.5% (95% CI: 85.2-94.1%) in lipid and 88.5% (95% CI: 82.4-92.7%) in calcium. The median time required for analysis was 21.4 (18.6-25.0) seconds per pullback., Conclusions: A novel AI framework for automatic plaque characterisation in IVOCT was developed, providing excellent diagnostic accuracy in both internal and external validation. This model might reduce subjectivity in image interpretation and facilitate IVOCT quantification of plaque composition, with potential applications in research and IVOCT-guided PCI.

Background: We aimed to assess the effects of safinamide on depression, motor symptoms, and the serotonin syndrome related to its co-administration with antidepressants in patients with Parkinson's disease (PD)., Methods: We retrospectively analyzed the data of patients at 1 and 3 months of follow-up compared to baseline., Results: n = 82 (safinamide 50 mg = 22, 100 mg = 60, with antidepressants = 44). First, we found improvement in depression (Hamilton Depression Rating Scale: -6 ± 5.10 at 1 month and -7.27 ± 5.10 at 3 months, p < 0.0001; Patient Global Impression of Improvement Scale: 60.3% and 69.5% of patients at 1 and 3 months reported some improvement). Second, safinamide improved the daily life activities and motor symptoms/motor complications (Unified Parkinson's Disease Rating Scale (UPDRS-II): -2.51 ± 6.30 and -2.47 ± 6.11 at 1 and 3 months, p < 0.0001; III: -3.58 ± 8.68 and -4.03 ± 8.95 at 1 and 3 months, p < 0.0001; IV: -0.61 ± 2.61 and -0.8 ± 2.53 at 1 and 3 months, p < 0.0001). Third, 7.31% and 8.53% of patients developed non-severe adverse events related to safinamide at 1 and 3 months. Serotonin syndrome was not observed in the patients treated with antidepressants; some isolated serotonin syndrome symptoms were reported., Conclusions: Safinamide could be useful for treating depression in PD; it was effective for motor symptoms and motor complications and safe even when co-administered with antidepressants.

Background: Primary percutaneous coronary intervention (pPCI) in ST-segment elevation myocardial infarction (STEMI) can be challenging for high thrombus burden and catecholamine-induced vasoconstriction. The Xposition-S stent was designed to prevent stent undersizing and minimize strut malapposition. We evaluated 1-year clinical outcomes of a nitinol, self-apposing®, sirolimus-eluting stent, pre-mounted on a novel balloon delivery system, in de novo lesions of patients presenting with STEMI undergoing pPCI., Methods: The iPOSITION is a prospective, multicenter, post-market, observational study. The primary endpoint, target lesion failure (TLF), was defined as the composite of cardiac death, recurrent target vessel myocardial infarction (TV-MI), and clinically driven target lesion revascularization (TLR)., Results: The study enrolled 247 STEMI patients from 7 Italian centers. Both device and procedural success occurred in 99.2% of patients, without any death, TV-MI, TLR, or stent thrombosis during the hospital stay and at 30-day follow-up. At 1 year, TLF occurred in 2.6%, cardiac death occurred in 1.7%, TV-MI occurred in 0.4%, and TLR in 0.4% of patients. The 1-year stent thrombosis rate was 0.4%., Conclusions: The use of an X-position S self-apposing® stent is feasible in STEMI pPCI, with excellent post-procedural results and 1-year outcomes.

Introduction: Coronary Bifurcation lesions are technically more challenging and Bifurcation percutaneous coronary intervention (PCI) remains a challenge with unpredictable and sub-optimal clinical and angiographic results. Drug-Coated Balloons (DCB) are emerging devices in the field of coronary intervention with promising results that may overcome some of drug eluting stents limitations and may have potential advantages in complex bifurcation PCI., Areas Covered: We have performed a re-appraisal about the issues with current bifurcation PCI techniques and the use of DCB in the treatment of Bifurcation lesions. Several studies performed utilizing DCB are described and critically appraised. Over the recent years, there have been tremendous developments in the DCB technology, lesion preparation, clinical experience, and clinical data during bifurcation PCI. The current review describes the advances in the DCB technology, pharmacokinetics, role of excipients, and optimization of the technique. Special emphasis in lesion preparation and potential pathway of using DCB in bifurcation PCI is proposed., Expert Opinion: Although different proof of concept and pilot studies have shown promising results in treatment of bifurcation lesions with DCB, larger randomized trials and/or international consensus papers are required to enable worldwide translation of this idea to clinical practice.

Aims: The aim of this study was to evaluate the diagnostic performance of OCT-based optical flow ratio (OFR) in unselected patients and compare it with angiography-based quantitative flow ratio (QFR), using wire-based FFR as reference standard., Methods and Results: All patients with OCT and FFR assessment prior to revascularisation were analysed. OFR and QFR were computed in a blinded fashion and compared with FFR, applying the same cut-off value of ≤0.80 to all to define ischaemia. Paired comparison between OFR and QFR was performed in 212 vessels from 181 patients. Average FFR was 0.82±0.10 and 40.1% of vessels had an FFR ≤0.80. OFR showed a significantly better correlation and agreement with FFR than QFR (r=0.87 versus 0.77, p<0.001; SD of the difference=0.05 versus 0.07, p<0.001). The AUC was 0.97 for OFR, higher than for QFR (difference=0.05, p=0.017), and much higher than the minimal lumen area (difference=0.15, p<0.001) and diameter stenosis (difference=0.17, p<0.001). Diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio for OFR to identify FFR ≤0.80 were 92%, 86%, 95%, 92%, 91%, 18.2 and 0.2, respectively. The diagnostic accuracy of OFR was not significantly different in MI-related vessels (95% versus 90%, p=0.456), or in vessels with and without previously implanted stents (90% versus 93%, p=0.669)., Conclusions: OFR had an excellent agreement with FFR in consecutive patients with coronary artery disease. OFR was superior to QFR, and much better than conventional morphological parameters in determining physiological significance of coronary stenosis. The diagnostic performance of OFR was not influenced by the presence of prior myocardial infarction or implanted stents.

Intravascular optical coherence tomography (IVOCT) can accurately assess stent apposition and expansion, thus enabling the optimisation of a stenting procedure to minimize the risk of device failure. This paper presents a deep convolutional based model for automatic detection and segmentation of stent struts. The input of pseudo-3D images aggregated the information from adjacent frames to refine the probability of strut detection. In addition, multi-scale shortcut connections were implemented to minimize the loss of spatial resolution and refine the segmentation of strut contours. After training, the model was independently tested in 21,363 cross-sectional images from 170 IVOCT image pullbacks. The proposed model obtained excellent segmentation (0.907 Dice and 0.838 Jaccard) and detection metrics (0.943 precision, 0.940 recall and 0.936 F1-score), significantly better than conventional features-based algorithms. This performance was robust and homogenous among IVOCT pullbacks with different sources of acquisition (clinical centres, imaging operators, type of stent, time of acquisition and challenging scenarios). In addition, excellent agreement between the model and a commercialized software was observed in the quantification of clinically relevant parameters. In conclusion, the deep-convolutional model can accurately detect stent struts in IVOCT images, thus enabling the fully-automatic quantification of stent parameters in an extremely short time. It might facilitate the application of quantitative IVOCT analysis in real-world clinical scenarios., Competing Interests: ST: Pulse medical imaging technology. (I,F). The other authors declare no conflicts of interest related to this article., (© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.)

Heterogeneous neointimal response has been observed after implantation of all generations of coronary stents. Our aim was assessing local factors of shear stress (SS) and plaque characteristics in neointimal response after implantation of bioresorbable scaffolds (BRS) in bifurcations. Ten patients from the BIFSORB pilot study were analysed. Follow-up optical frequency domain imaging (OFDI) was performed at 1 month and 2 years. Coronary lumen and BRS structure were reconstructed by fusion of OFDI and angiography and were used for subsequent flow simulation. Plaque arc degree and SS were quantified using post-procedural OFDI data and were matched with follow-up OFDI using anatomical landmarks. Strut-level and segment-level analysis were performed for 1-month and 2-year follow-up respectively. A total of 444 struts (54 jailing struts) were included at 1-month follow-up. Time-average SS (TASS) was significantly lower for covered struts than for uncovered struts in non-bifurcation segments (TASS: 1.81 ± 1.87 vs. 3.88 ± 3.72 Pa, p < 0.001). The trend remained the same for jailing struts, although statistically insignificant (TASS: 10.85 ± 13.12 vs. 13.64 ± 14.48 Pa, p = 0.328). For 2-year follow-up, a total of 66 sub-regions were analysed. Neointimal hyperplasia area (NTA) was negatively correlated with TASS in core-segments (ρ = - 0.389, p = 0.037) and positively correlated with plaque arc degree in non-core segments (ρ = 0.387, p = 0.018). Slightly stronger correlations with NTA were observed when combining TASS and plaque arc degree in both core segments (ρ = - 0.412, p = 0.026) and non-core segments (ρ = - 0.395, p = 0.015). Hemodynamic microenvironment and baseline plaque characteristics may regulate neointimal response after BRS implantation in bifurcation. These findings underline the combined role of plaque characteristics and local hemodynamics in vessel healing after stent implantation.

Background: The side branch (SB) compromise after main vessel (MV) stenting remains a significant problem in coronary bifurcation treatment. Currently the two major hypotheses for the mechanism of SB compromise are carina shift from MV into the SB and plaque shift into the ostium of side vessel. It is proposed herein, SB ostial deformation leading to reshaping of the ostium from circle to ellipse is a third possible mechanism. In the current study, the theoretical effects and correlation of ostial deformation with fractional flow reserve (FFR) is explored., Methods: Based on angiographic measurements and theoretical analysis formulas, three different SB ostial areas using circular ostial shape assumption and elliptical ostial shape assumption were calculated. Three different types of ostial areas with FFR values after MV stenting in 49 patients from the FIESTA registry were compared and analyzed., Results: It was found that there is significant overestimation of stenosis severity when estimated by the circle formula, than with the ellipse formula - ASc vs. ASds with 25% ± 13%, p < 0.001, ASc vs. ASmld with 9% ± 10%, p < 0.001. The elliptical shape assumptions provide more accurate ostial area stenosis, which correlates better with FFR. This finding is more significant in less severe stenosis (< 70% area stenosis) than in a more severe one., Conclusions: A third possible mechanism of SB compromise after MV stenting of coronary bifurcation stenosis is elliptical ostial deformation at the ostium of SBs. The ostial area, calculated based on elliptical assumption correlates better with FFR, than area stenosis calculated with the traditional circular formula.

Background: Evaluating prospectively the feasibility, accuracy and reproducibility of optical flow ratio (OFR), a novel method of computational physiology based on optical coherence tomography (OCT)., Methods and Results: Sixty consecutive patients (76 vessels) underwent prospectively OCT, angiography- based quantitative flow ratio (QFR) and fractional flow ratio (FFR). OFR was computed offline in a central core-lab by analysts blinded to FFR. OFR was feasible in 98.7% of the lesions and showed excellent agreement with FFR (ICCa = 0.83, r = 0.83, slope = 0.80, intercept = 0.17, kappa = 0.84). The area under curve to predict an FFR ≤ 0.80 was 0.95, higher than for QFR (0.91, p = 0.115) and for minimal lumen area (0.64, p < 0.001). Diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio were 93%, 92%, 93%, 88%, 96%, 13.8, 0.1, respectively. Median time to obtain OFR was 1.07 (IQR: 0.98-1.16) min, with excellent intraobserver and interobserver reproducibility (0.97 and 0.95, respectively). Pullback speed had negligible impact on OFR, provided the same coronary segment were imaged (ICCa = 0.90, kappa = 0.697)., Conclusions: The prospective computation of OFR is feasible and reproducible in a real-world series, resulting in excellent agreement with FFR, superior to other image-based methods.

Background: A simplified formula to calculate the predicted fractional flow reserve (FFR) in sequen-tial coronary stenosis without balloon inflation is hereby proposed., Methods: In patients with an indication for FFR and sequential coronary stenosis, FFR was recorded distally and between the lesions. The predicted FFR for each stenosis was calculated with a novel formu-la. While treating one of the lesions, wedge pressure was measured during balloon inflation to calculate Pijls' formula. FFR of the remaining lesion was finally recorded (measured FFR)., Results: Forty patients were enrolled in the study, 4 (10.0%) had a distal FFR > 0.80 and were excluded from the main analysis. In the remaining 36 patients, the novel formula and Pijls' formula showed virtually absolute agreement (ICCa 0.999, R2 = 0.997 for the proximal lesion, R2 = 0.999 for the distal lesion, kappa 1.000, Se 100%, Sp 100%). The agreement between predicted and measured FFR was good (ICCa 0.820; 0.640-0.909, R2 = 0.717, intercept = 0.05, slope = 0.92, kappa 0.748, Se 75%, Sp 96%). In 19 (47.5%) cases the use of the formula enabled the operator to freely decide which lesion should be treated first, an option not available if the percutaneous coronary intervention (PCI) were guided by the largest pressure drop across each lesion., Conclusions: The predicted FFR for each lesion in sequential coronary stenosis can be accurately calculated by a simplified formula circumventing the need for balloon inflation. This approach provides the operator upfront, with detailed information on physiology, thus having a potentially high impact on the corresponding PCI strategy.

Background: Percutaneous coronary intervention in complex bifurcation lesions is prone to suboptimal implantation results and is associated with increased risk of subsequent clinical events. Angiographic ambiguity is high during bifurcation stenting, but it is unknown if procedural guidance by intravascular optical coherence tomography (OCT) improves clinical outcome., Methods and Design: OCTOBER is a randomized, investigator-initiated, multicenter trial aimed to show superiority of OCT-guided stent implantation compared to standard angiographic-guided implantation in bifurcation lesions. The primary outcome measure is a 2-year composite end point of cardiac death, target lesion myocardial infarction, and ischemia-driven target lesion revascularization. The calculated sample size is 1,200 patients in total, and allocation is 1:1. Eligible patients have stable or unstable angina pectoris or stabilized non–ST elevation myocardial infarction, and a coronary bifurcation lesion with significant main vessel stenosis and more than 50 % stenosis in a side branch with a reference diameter ≥2.5mm. Treatment is performed by the provisional side branch stenting technique or 2-stent techniques, and the systematic OCT guiding protocol is aimed to evaluate (1) plaque preparation, (2) lesion length, (3) segmental reference sizes, (4) lesion coverage, (5) stent expansion, (6) malapposition, (7) wire positions, and (8) ostial results., Implications: A positive outcome of the OCTOBER trial may establish OCT as a routine tool for optimization of complex percutaneous coronary intervention, whereas a negative result would indicate that OCT remains a tool for ad hoc evaluation in selected cases., (© 2018 The Authors. Published by Elsevier Inc.)

The purpose of this study was to evaluate the impact of prebifurcation renal denervation in a swine model and assess its safety through optical coherence tomography (OCT). Prebifurcation renal denervation with a multi-electrode catheter was performed in one renal artery of 12 healthy pigs, with the contralateral artery and kidney being used as controls. Angiograms and OCT pullbacks were obtained peri-procedurally and 1 month post procedure. Renal tissue catecholamines were quantified, and the arterial wall and peri-adventitial tissue were analyzed histologically. Intraluminal changes (endothelial swelling, spasm, and thrombus formation) were observed acutely by OCT in most of the treated arteries and were no longer visible at follow-up. Histology revealed a statistically significant accumulation of collagen (fibrosis) and a near absence of tyrosine hydroxylase labeling in the denervated artery, suggesting a clear reduction in nervous terminals. Renal tissue catecholamine levels were similar between both sides, probably due to the low number of ablation points and the renorenal reflex. The present study demonstrates that renal denervation is associated with acute intimal disruptions, areas of fibrosis, and a reduction in nervous terminals. The lack of difference in renal tissue catecholamine levels is indicative of the need to perform the highest and safest number of ablation points in both renal arteries. These findings are important because they demonstrate the histological consequences of radiofrequency energy application and its medium-term safety.