Innovations in the clinical use of OCT

Optical coherence tomography (OCT) is an infrared light-based imaging modality with near-histological resolution (5-15μm) allowing the comprehensive evaluation of the vascular wall and intracoronary devices. This imaging modality has been widely used in clinical practice for the assessment of atherosclerosis and of the impact of interventions on the vascular wall, but also for the guidance of coronary intervention. The aim of this thesis is to outline the contemporary use of optical coherence tomography in clinical practice and summarize insights gained by this imaging modality into the acute and chronic vascular response after intravascular interventions. In specific, this thesis intends to: - Summarize the current status of OCT in clinical practice - Describe and validate new analysis tools for optical coherence tomography, that allow to overcome some of the current limitations - Examine the pathomechanisms of very late metallic stent failure with particular emphasis on the role of neoatherosclerosis - Assess the acute and chronic vascular healing response after bioresorbable vascular scaffold implantation and provide pilot observations regarding the pathomechanisms of early and late bioresorbable scaffold failure - Evaluate the acute effects of catheter-based renal denervation on the renal artery integrit

Association of systemic inflammatory biomarkers with morphological characteristics of coronary atherosclerotic plaque by intravascular optical coherence tomography

Despite significant advances in preventive, medical, and interventional management, coronary artery disease remains the leading cause of death worldwide. We now know that in the majority of acute coronary syndromes, a thrombotic event is triggered either by the rupture or erosion of the so-called high-risk or ‘vulnerable’ plaque. However, accurately identifying the individual who is at significant risk of acute event remains the holy grail of preventive cardiology. To better stratify an individual's risk of developing and suffering a cardiovascular event, biomarkers are needed that can accurately predict coronary events and, if possible, monitor disease activity in response to medical or interventional therapies. In order to be able to understand the association of these biomarkers with the morphological substrate of high-risk plaques, intravascular imaging modalities can provide invaluable assistance. Novel imaging tools such as optical coherence tomography (OCT) have not only helped in identifying atherosclerotic plaque characteristics that are unstable but also in estimating global plaque burden. In this study, we provide an overview of our current knowledge of association of various inflammatory markers with atherosclerotic plaque characteristics seen on OCT

Is it safe to implant bioresorbable scaffolds in ostial side-branch lesions? Impact of 'neo-carina' formation on main-branch flow pattern. Longitudinal clinical observations

Formation of a 'neo-carina' has been reported after bioresorbable vascular scaffolds (BVS) implantation over side-branches. However, as this 'neo-carina' could protrude into the main-branch, its hemodynamic impact remains unknown. We present two cases of BVS implantation for ostial side-branch lesions, and investigate the flow patterns at follow-up and their potential impact. Computational fluid dynamics analysis was performed, using a 3D mesh created by fusion of 3-dimensional angiogram with optical coherence tomography images. In our first case, mild disturbances were seen when 'neo-carina' did not protrude perpendicularly into the main branch. In the second case, extensive flow re-distribution was observed due to a more pronounced protrusion of the 'neo-carina'. Importantly, these areas of hemodynamic disturbance were observed together with lumen narrowing in a non-stenotic vessel segment. Our case observations highlight the importance of investigating the hemodynamic consequences of BVS implantation in bifurcation lesions and illustrate a novel method to do so invivo

Quantification of fibrous cap thickness in intracoronary optical coherence tomography with a contour segmentation method based on dynamic programming

OBJECTIVES: Fibrous cap thickness is the most critical component of plaque stability. Therefore, in vivo quantification of cap thickness could yield valuable information for estimating the risk of plaque rupture. In the context of preoperative planning and perioperative decision making, intracoronary optical coherence tomography imaging can provide a very detailed characterization of the arterial wall structure. However, visual interpretation of the images is laborious, subject to variability, and therefore not always sufficiently reliable for immediate decision of treatment. METHODS: A novel semiautomatic segmentation method to quantify coronary fibrous cap thickness in optical coherence tomography is introduced. To cope with the most challenging issue when estimating cap thickness (namely the diffuse appearance of the anatomical abluminal interface to be detected), the proposed method is based on a robust dynamic programming framework using a geometrical a priori. To determine the optimal parameter settings, a training phase was conducted on 10 patients. RESULTS: Validated on a dataset of 179 images from 21 patients, the present framework could successfully extract the fibrous cap contours. When assessing minimal cap thickness, segmentation results from the proposed method were in good agreement with the reference tracings performed by a medical expert (mean absolute error and standard deviation of [Formula: see text] ) and were similar to inter-observer reproducibility ([Formula: see text] , R = .74), while being significantly faster and fully reproducible. CONCLUSION: The proposed framework demonstrated promising performances and could potentially be used for online identification of high-risk plaques

Optical Coherence Tomography: Potential Clinical Applications

Optical coherence tomography (OCT) is a novel intravascular imaging modality using near-infrared light. By OCT it is possible to obtain high-resolution cross-sectional images of the vascular wall structure and assess the acute and long-term effects of percutaneous coronary intervention. For the time being OCT has been mainly used in research providing new insights into the pathophysiology of the atheromatic plaque and of the vascular res

Are BVS suitable for ACS patients? Support from a large single center real live registry

Objectives To investigate one-year outcomes after implantation of a bioresorbable vascular scaffold (BVS) in patients presenting with acute coronary syndrome (ACS) compared to stable angina patients. Background Robust data on the outcome of BVS in the setting of ACS is still scarce. Methods Two investigator initiated, single-center, single-arm BVS registries have been pooled for the purpose of this study, namely the BVS Expand and BVS STEMI registries. Results From September 2012-Octob

Early and late optical coherence tomography findings following everolimus-eluting bioresorbable vascular scaffold implantation in myocardial infarction: A preliminary report

Introduction: Although bioresorbable vascular scaffolds (BVS) have been used with promising results in patients with stable and unstable angina, little is known about the acute vascular response following BVS implantation in myocardial infarction. We present angiographic and OCT findings from the first patients undergoing bioresorbable vascular scaffold (BVS) implantation for non-ST-elevation myocardial infarction (NSTEMI) or ST-elevation myocardial infarction (STEMI) in our institution. Methods: The first 5 patients with NSTEMI and the first 5 patients with STEMI who underwent BVS implantation in our institution, followed by optical coherence tomography (OCT) imaging of the treated culprit vessel, were included in this series. All patients underwent angiographic analysis pre- and post- BVS implantation, as well as OCT analysis, including qualitative and quantitative assessment. Results: Implantation was successful in all cases, as assessed by angiography and OCT. There were no cases with coronary spasm, distal embolization or no-reflow. No adverse clinical events were recorded in any patient at the 6-month follow up. Specific illustrative cases demonstrating the challenges of BVS implantation in myocardial infarction are presented. Conclusions: BVS implantation can potentially be used in the setting of thrombotic lesions encountered in myocardial infarction; however, the role of this treatment approach warrants systematic evaluation in prospective studies

OCT assessment of the long-term vascular healing response 5 years after everolimus-eluting bioresorbable vascular scaffold

AbstractBackgroundAlthough recent observations suggest a favorable initial healing process of the everolimus-eluting bioresorbable vascular scaffold (BVS), little is known regarding long-term healing response.ObjectivesThis study assessed the in vivo vascular healing response using optical coherence tomography (OCT) 5 years after elective first-in-man BVS implantation.MethodsOf the 14 living patients enrolled in the Thoraxcenter Rotterdam cohort of the ABSORB A study, 8 patients underwent invasive follow-up, including OCT, 5 years after implantation. Advanced OCT image analysis included luminal morphometry, assessment of the adluminal signal-rich layer separating the lumen from other plaque components, visual and quantitative tissue characterization, and assessment of side-branch ostia “jailed” at baseline.ResultsIn all patients, BVS struts were integrated in the vessel and were not discernible. Both minimum and mean luminal area increased from 2 to 5 years, whereas lumen eccentricity decreased over time. In most patients, plaques were covered by a signal-rich, low-attenuating layer. Minimum cap thickness over necrotic core was 155 ± 90 μm. One patient showed plaque progression and discontinuity of this layer. Side-branch ostia were preserved with tissue bridge thinning that had developed in the place of side-branch struts, creating a neo-carina.ConclusionsAt long-term BVS follow-up, we observed a favorable tissue response, with late luminal enlargement, side-branch patency, and development of a signal-rich, low-attenuating tissue layer that covered thrombogenic plaque components. The small size of the study and the observation of a different tissue response in 1 patient warrant judicious interpretation of our results and confirmation in larger studies

Initial experience with everolimus-eluting bioresorbable vascular scaffolds for treatment of patients presenting with acute myocardial infarction

Aims: Limited data are currently available on midterm outcomes after implantation of everolimus-eluting bioresorbable vascular scaffolds (BVS) for treatment of acute ST-elevation myocardial infarction (STEMI). Methods and results: Patients presenting with STEMI and undergoing primary percutaneous coronary intervention in the initial experience with BVS were evaluated and compared with patients treated with everolimus-eluting metal stents (EES) by applying propensity matching. Quantitative coronary angiography analysis, and 18-month clinical follow-up were reported. A total of 302 patients were analysed, 151 with BVS and 151 with EES. Baseline clinical characteristics were similar between groups. Final TIMI 3 flow was 87.4% vs. 86.1%, p=0.296. At 18-month follow-up, all-cause mortality was 2.8% vs. 3.0% in the BVS and EES groups respectively, p=0.99; the MACE rate was higher in the BVS group (9.8% vs. 3.6%, p=0.02); target lesion revascularisation was 5.7% vs. 1.3%, p=0.05. The 30-day MACE rate in BVS patients without post-dilatation was 6.8%, while in patients with post-dilatation it was 3.6%. Scaffold thrombosis (ST) occurred primarily in the acute phase (acute ST 2.1% vs. 0.7%, p=0.29; subacute 0.7% vs. 0.7%, p=0.99; late 0.0% vs. 0.0%; very late 1.5% vs. 0.0%, p=0.18). All three BVS cases with acute ST had no post-dilatation at the index procedure. Conclusions: STEMI patients treated during the early experience with BVS had similar acute angiographic results as compared with the EES group. Clinical midterm follow-up data showed a higher clinical events rate compared with metal stents. The majority of clinical events occurred in the early phase after implantation and mainly in cases without post-dilatation. Optimisation of the implantation technique in the acute clinical setting is of paramount importance for optimal short and mid-term outcomes