Optical Coherence Tomography to Optimize Results of Percutaneous Coronary Intervention in Patients with Non-ST-Elevation Acute Coronary Syndrome: Results of the Multicenter, Randomized DOCTORS Study (Does Optical Coherence Tomography Optimize Results of Stenting)

A Vision Of Percutaneous Coronary Revascularisation In 2021: How to take advantage of intra-coronary imaging to perform more effective PCI

The use of intracoronary imaging with intravascular ultrasound (IVUS) or optical coherence tomography (OCT) can define vessel architecture and has an established role in guidance and optimisation of percutaneous coronary intervention. Additionally intracoronary imaging has an emerging role in diagnosis, afforded by the ability to depict vessel wall characteristics not seen on angiography alone. Use of intracoronary imaging is recommended by international consensus guidelines from the European Society of Cardiology and two recent expert consensus position statements from the European Association of Percutaneous Coronary Interventions (EAPCI). However, uptake in contemporary practice in the United Kingdom appears to lag behind these recommendations. Imaging is particularly advantageous in complex coronary lesions (such as left main stem coronary artery, bifurcation, or heavily calcified lesions) and in complex patients (acute presentations, atypical presentations, and renal dysfunction). Stent detail to the level of individual struts can be appreciated with intracoronary imaging, which facilitates appropriate stent selection and optimisation of the final stent result. We highlight specific subgroups that benefit from an imaging guided approach to percutaneous coronary intervention. We review the evidence and the role of intracoronary imaging and highlight specific subgroups that show particular benefit from imaging guided percutaneous coronary intervention.

Optical Coherence Tomography: Current Applications for the Assessment of Coronary Artery Disease and Guidance of Percutaneous Coronary Interventions

INTRODUCTION

Coronary angiography (CAG) is the standard modality for assessment of coronary stenoses and intraprocedural guidance of percutaneous coronary interventions (PCI). However, the limitations of CAG are well recognized. Intracoronary imaging (ICI) can potentially overcome these limitations. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are the main ICI techniques utilized in clinical practice.

AIM

This narrative literature review addresses the current clinical applications of OCT in relation to IVUS and CAG in patients with coronary artery disease (CAD). Items reviewed are: technical implications of OCT and IVUS, lesion characterization and decision-making, stent optimization criteria, post-stenting results, safety in terms of procedural complications, clinical outcomes, and indications.

MAIN FINDINGS

OCT is able to reveal more detail than IVUS due to its higher resolution. However, this higher resolution comes at the cost of a lower penetration depth. Pre-stenting OCT results in procedural change in more than 50% of the cases in terms of stent length and diameter. Post-stenting OCT resulting in stent optimization is reported in at least 27% of the cases. Malapposition and under-expansion are treated with post-dilatations, while edge dissections are treated with additional stent placement. Stent expansion, stent apposition, distal stent edge dissections, and reference lumen areas seem to be the most important stent optimization criteria for both decision-making and for reducing the risk of adverse events during follow-up. Both OCT and IVUS are superior in terms of post-stenting results compared with CAG alone. However, there is no consensus about whether OCT guidance results in better stent expansion than IVUS guidance. OCT, IVUS, and CAG are safe procedures with few reported procedural complications. In general, OCT guidance seems to contribute to favorable clinical outcomes compared with CAG guidance only. However, OCT guidance results in similar clinical outcomes as with IVUS guidance. OCT could be considered for lumen assessment and stent-related morphology in more complex cases in which CAG interpretation remains uncertain. Since OCT and IVUS have distinct characteristics, these techniques are complementary and should be considered carefully for each patient case based on the benefits and limitations of both techniques.

Impact of optical coherence tomography findings on clinical outcomes in ST-segment elevation myocardial infarction patients: a MATRIX (Minimizing Adverse Hemorrhagic Events by Trans-radial Access Site and angioX) OCT sub-study

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 1 year. 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 (> 200 µm in width and < 5 mm from stent segment), malapposition (> 200 µm 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 30 day and 1 year 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 30 days 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.

Applications and future directions for optical coherence tomography in dermatology

Optical coherence tomography (OCT) is a noninvasive optical imaging method that can generate high-resolution en face and cross-sectional images of the skin in vivo to a maximum depth of 2 mm. While OCT holds considerable potential for noninvasive diagnosis and disease monitoring, it is poorly understood by many dermatologists. Here we aim to equip the practising dermatologist with an understanding of the principles of skin OCT and the potential clinical indications. We begin with an introduction to the technology and discuss the different modalities of OCT including angiographic (dynamic) OCT, which can image cutaneous blood vessels at high resolution. Next we review clinical applications. OCT has been most extensively investigated in the diagnosis of keratinocyte carcinomas, particularly basal cell carcinoma. To date, OCT has not proven sufficiently accurate for the robust diagnosis of malignant melanoma; however, the evaluation of abnormal vasculature with angiographic OCT is an area of active investigation. OCT, and in particular angiographic OCT, also shows promise in monitoring the response to therapy of inflammatory dermatoses, such as psoriasis and connective tissues disease. We additionally discuss a potential role for artificial intelligence in improving the accuracy of interpretation of OCT imaging data.

Intravascular Polarimetry: Clinical Translation and Future Applications of Catheter-Based Polarization Sensitive Optical Frequency Domain Imaging

Optical coherence tomography (OCT) and optical frequency domain imaging (OFDI) visualize the coronary artery wall and plaque morphology in great detail. The advent of these high-resolution intracoronary imaging modalities has propelled our understanding of coronary atherosclerosis and provided enhanced guidance for percutaneous coronary intervention. Yet, the lack of contrast between distinct tissue types and plaque compositions impedes further elucidation of the complex mechanisms that contribute to acute coronary syndrome (ACS) and hinders the prospective identification of plaques susceptible to rupture. Intravascular polarimetry with polarization-sensitive OFDI measures polarization properties of the coronary arterial wall using conventional intravascular imaging catheters. The quantitative polarization metrics display notable image contrast between several relevant coronary plaque microstructures that are difficult to identify with conventional OCT and OFDI. Tissues rich in collagen and smooth muscle cells exhibit birefringence, while lipid and macrophages cause depolarization. In this review, we describe the basic principles of intravascular polarimetry, discuss the interpretation of the polarization signatures, and outline promising avenues for future research and clinical implications.

Comparison of optical coherence tomography-guided versus intravascular ultrasound-guided percutaneous coronary intervention: Rationale and design of a randomized, controlled OCTIVUS trial

BACKGROUND

The clinical value of intracoronary imaging for percutaneous coronary intervention (PCI) guidance is well acknowledged. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are the most commonly used intravascular imaging to guide and optimize PCI in day-to-day practice. However, the comparative effectiveness of IVUS-guided versus OCT-guided PCI with respect to clinical end points remains unknown.

METHODS AND DESIGN

The OCTIVUS study is a prospective, multicenter, open-label, parallel-arm, randomized trial comparing the effectiveness of 2 imaging-guided strategies in patients with stable angina or acute coronary syndromes undergoing PCI in Korea. A total of 2,000 patients are randomly assigned in a 1:1 ratio to either an OCT-guided PCI strategy or an IVUS-guided PCI strategy. The trial uses a pragmatic comparative effectiveness design with inclusion criteria designed to capture a broad range of real-world patients with diverse clinical and anatomical features. PCI optimization criteria are predefined using a common algorithm for online OCT or IVUS. The primary end point, which was tested for both noninferiority (margin, 3.1 percentage points for the risk difference) and superiority, is target-vessel failure (cardiac death, target-vessel myocardial infarction, or ischemia-driven target-vessel revascularization) at 1 year.

RESULTS

Up to the end of July 2020, approximately 1,200 "real-world" PCI patients have been randomly enrolled over 2 years. Enrollment is expected to be completed around the midterm of 2021, and primary results will be available by late 2022 or early 2023.

CONCLUSION

This large-scale, multicenter, pragmatic-design clinical trial will provide valuable clinical evidence on the relative efficacy and safety of OCT-guided versus IVUS-guided PCI strategies in a broad population of patients undergoing PCI in the daily clinical practice.

How can optical coherence tomography be used to optimize percutaneous coronary intervention?

Optical coherence tomography (OCT) imaging provides high resolution assessment of coronary parietal and endoluminal abnormalities. Clinical evidence and intuitive utilization make this tool relevant for use in daily practice in the catheterization laboratory. In the present review, we summarize the benefits of OCT for the optimization of percutaneous coronary intervention (PCI) in daily practice. First, we focus on the characterization of lesion type with a view to anticipating challenges during PCI. Then, we describe the utility of OCT to identify culprit lesions and ambiguous angiographic findings. Finally, we outline targets for optimization after PCI and the mechanisms underlying stent failure.

Comparison of Stent Expansion Using a Volumetric Versus the Conventional Method Through Optical Coherence Tomography in an All-Comers Population

INTRODUCTION

A volumetric approach to measure stent expansion derived from optical coherence tomography (OCT) is superior in regards to clinical outcomes when compared to the conventional method. The current software already performs a semi-automatic assessment and it is available as a clinical tool, however data is still scarce. We evaluated the stent expansion analysis that uses a volumetric vessel model, called minimum expansion index - MEI and compared to the conventional model, which utilizes the minimum stent area expansion (MSAx) indexed to the references, and its potential impact on procedural decision-making strategy in percutaneous coronary intervention.

METHODS

This was a prospective, all-comers single center study, from all patients undergoing OCT-guided PCI between September 2018 and May 2019. We utilized the APTIVUE™ OPTIS 5.2 software (Abbott, Santa Clara, CA) to evaluate MEI and MSAx measurements after reference adjustments.

RESULTS

We included 100 patients with mean age of 64 ± 12.5 years, 68% were men, and the main arteries analyzed through OCT were LAD (48%), RCA (31%) and LCx (21%). The mean MEI was 77.6% ± 16.7% and the mean MSAx was 71.6% ± 16.9%. MEI location differed from MSAx in 70% of cases, and in those cases the mean distance between MEI and MSAx was 15.3 mm ± 12.4 mm. In 53% of the times, the stent underexpansion based on MEI was located proximally to the MSAx by 18.1 mm ± 11.8 mm. Furthermore, in 42% of the total cases, MEI would change the intervention strategy based on the stent underexpansion being in a different location ≥10 mm in comparison to MSAx (34%) associated with the discrepancy between expansion indexes for MEI and MSAx (22%).

CONCLUSION

We concluded that MEI location did not correlate to the conventional MSAx in two thirds of the cases. Moreover, compared to MEI, the MSAx assessment yielded lower expansion values in different stent positions, potentially changing the appropriate post-stent optimization, which thus would impact the decision-making strategy in almost half of the patients.

Impact of real-time angiographic co-registered optical coherence tomography on percutaneous coronary intervention: the OPTICO-integration II trial

Aims

Longitudinal geographic mismatch (LGM) as well as edge dissections are associated with an increased risk of adverse events after percutaneous coronary intervention (PCI). Recently, a novel system of real-time optical coherence tomography (OCT) with angiographic co-registration (ACR) became available and allows matched integration of cross-sectional OCT images to angiography. The OPTICO-integration II trial sought to assess the impact of ACR for PCI planning on the risk of LGM and edge dissections.

Methods

A total of 84 patients were prospectively randomized to ACR-guided PCI, OCT-guided PCI (without co-registration), and angiography-guided PCI. Primary endpoint was a composite of major edge dissection and/or LGM as assessed by post-PCI OCT.

Results

The primary endpoint was significantly reduced in ACR-guided PCI (4.2%) as compared to OCT-guided PCI (19.1%; p = 0.03) and angiography-guided PCI (25.5%; p < 0.01). Rates of LGM were 4.2%, 17.0%, and 22.9% in the ACR-guided PCI, in the OCT-guided PCI, and the angiography-guided PCI groups, respectively (ACR vs. OCT p = 0.04; ACR vs. angiography p = 0.04). The number of major edge dissections was low and without significant differences among the study groups (0% vs. 2.1% vs. 4.3%).

Conclusion

This study for the first time demonstrates superiority of ACR-guided PCI over OCT- and angiography-guided PCI in reducing the composite endpoint of major edge dissection and LGM, which was meanly driven by a reduction of LGM.

Graphical abstract

Fractional Flow Reserve following Percutaneous Coronary Intervention

Fractional flow reserve (FFR) is routinely used to determine lesion severity prior to percutaneous coronary intervention (PCI). However, there is an increasing recognition that FFR may also be useful following PCI to identify mechanisms leading to restenosis and the need for repeat revascularization. Post-PCI FFR is associated with the presence and severity of stent under-expansion and may help identify peri-stent-related complications. FFR pullback may also unmask other functionally significant lesions within the target vessel that were not appreciable on angiography. Recent studies have confirmed the prognostic utility of performing routine post-PCI FFR and suggest possible interventional targets that would improve stent durability. In this review, we detail the theoretical basis underlying post-PCI FFR, provide practical tips to facilitate measurement, and discuss the growing evidence supporting its use.

OCT-NIRS Imaging for Detection of Coronary Plaque Structure and Vulnerability

A combination optical coherence tomography and near-infrared spectroscopy (OCT-NIRS) coronary imaging system is being developed to improve the care of coronary patients. While stenting has improved, complications continue to occur at the stented site and new events are caused by unrecognized vulnerable plaques. An OCT-NIRS device has potential to improve secondary prevention by optimizing stenting and by identifying vulnerable patients and vulnerable plaques. OCT is already in widespread use world-wide to optimize coronary artery stenting. It provides automated lumen detection and can identify features of coronary plaques not accurately identified by angiography or intravascular ultrasound. The ILUMIEN IV study, to be completed in 2022, will determine if OCT-guided stenting will yield better clinical outcomes than angiographic guidance alone. While the superb spatial resolution of OCT enables the identification of many plaque structural features, the detection by OCT of lipids, an important component of vulnerable plaques, is limited by suboptimal specificity and interobserver agreement. In contrast, NIRS has been extensively validated for lipid-rich plaque detection against the gold-standard of histology and is the only FDA-approved method to identify coronary lipids. Studies in patients have demonstrated that NIRS detects lipid in culprit lesions causing coronary events. In 2019, the positive results of the prospective Lipid-Rich Plaque Study led to FDA approval of NIRS for detection of high-risk plaques and patients. The complementarity of OCT for plaque structure and NIRS for plaque composition led to the sequential performance of NIRS and OCT imaging in patients. NIRS identified lipid while OCT determined the thickness of the cap over the lipid pool. The positive results obtained with OCT and NIRS imaging led to development of a prototype combined OCT-NIRS catheter that can provide co-registered OCT and NIRS data in a single pullback. The data will provide structural and chemical information likely to improve stenting and deliver more accurate identification of vulnerable plaques and vulnerable patients. More precise diagnosis will then lead to OCT-NIRS guided treatment trials to improve secondary prevention. Success in secondary prevention will then facilitate development of improved primary prevention with invasive imaging and effective treatment of patients identified by non-invasive methods.

Automatic stent reconstruction in optical coherence tomography based on a deep convolutional model

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.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention With Low-Molecular-Weight Dextran - Effect on Renal Function

BACKGROUND

The excessive volume of contrast needed is a significant limitation of optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI). Low-molecular-weight dextran (LMWD) has been used for OCT image acquisition instead of contrast media. This study compared the effects of OCT-guided PCI using LMWD on renal function and clinical outcomes to those of intravascular ultrasound (IVUS)-guided PCI.

METHODS AND RESULTS

In all, 1,183 consecutive patients who underwent intracoronary imaging-guided PCI were enrolled in this single-center, retrospective, observational study. After propensity score matching, 133 pairs of patients were assigned to undergo either OCT-guided PCI using LMWD or IVUS-guided PCI. There was no significant change from baseline in the primary endpoint, serum creatinine concentrations, after the procedure in either group. There were no significant differences between the OCT and IVUS groups in the volume of contrast medium, the incidence of contrast-induced nephropathy (1.5% vs. 2.3%; P=0.65), and major adverse cardiovascular events (MACE) at 30 days (2.3% vs. 6.0%; P=0.12) and 12 months (2.3% vs. 3.0%; P=0.70) after the procedure. Kaplan-Meier analysis at the 12-month follow-up revealed no significant difference in the incidence of MACE between the 2 groups (P=0.75).

CONCLUSIONS

OCT-guided PCI using LMWD did not negatively affect renal function and achieved similar short- and long-term clinical outcomes to IVUS-guided PCI.

A randomized controlled trial of a physiology-guided percutaneous coronary intervention optimization strategy: Rationale and design of the TARGET FFR study

Post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) ≥0.90 confers an improved cardiac prognosis. There are currently limited data available to determine how often it is possible to improve an angiographically acceptable but physiologically suboptimal result. A physiology-guided optimization strategy can achieve a clinically meaningful increase in the proportion of patients achieving a final post-PCI FFR ≥0.90 compared to standard care. Following angiographically successful PCI procedures, 260 patients will be randomized (1:1) to receive either a physiology-guided incremental optimization strategy (intervention group) or blinded post-PCI coronary physiology measurements (control group). Patients undergoing successful, standard-of-care PCI for either stable angina or non-ST-segment-elevation myocardial infarction who meet the study's inclusion and exclusion criteria will be eligible for randomization. The primary endpoint is defined as the proportion of patients with a final post-PCI FFR result ≥0.90. Secondary endpoints include change from baseline in Seattle Angina Questionnaire and EQ-5D-5L scores at 3 months and the rate of target vessel failure and its components (cardiac death, myocardial infarction, stent thrombosis, unplanned rehospitalization with target vessel revascularization) at 3 months and 1 year. 260 individual patients were successfully randomized between March 2018 and November 2019. Key baseline demographics of the study population are reported within. TARGET FFR is an investigator-initiated, prospective, single-center, randomized controlled trial of an FFR-guided PCI optimization strategy. The study has completed recruitment and is now in clinical follow-up. It is anticipated that primary results will be presented in Autumn 2020. ClinicalTrials.gov Identifier: NCT03259815. [Correction added on Apr 3 2020, after first online publication: Clinical Trials identifier added.].

Privileged Modality Distillation for Vessel Border Detection in Intracoronary Imaging

Intracoronary imaging is a crucial imaging technology in coronary disease diagnosis as it visualizes the internal tissue morphologies of coronary arteries. Vessel border detection in intracoronary images (VBDI) is desired because it can help the succeeding procedures of computer-aided disease diagnosis. However, existing VDBI methods suffer from the challenge of vessel-environment variability (i.e. high intra- and inter-subject diversity of vessels and their surrounding tissues appeared in images). This challenge leads to the ineffectiveness in the vessel region representation for hand-crafted features, in the receptive field extraction for deeply-represented features, as well as performance suppression derived from clinical data limitation. To solve this challenge, we propose a novel privileged modality distillation (PMD) framework for VBDI. PMD transforms the single-input-single-task (SIST) learning problem in the single-mode VBDI to a multiple-input-multiple-task (MIMT) problem by using the privileged image modality to help the learning model in the target modality. This learns the enriched high-level knowledge with similar semantics and generalizes PMD on diversity-increased low-level image features for improving the model adaptation to diverse vessel environments. Moreover, PMD refines MIMT to SIST by distilling the learned knowledge from multiple to one modality. This eliminates the reliance on privileged modality in the test phase, and thus enables the applicability to each of different intracoronary modalities. A structure-deformable neural network is proposed as an elaborately-designed implementation of PMD. It expands a conventional SIST network structure to the MIMT structure, and then recovers it to the final SIST structure. The PMD is validated on intravascular ultrasound imaging and optical coherence tomography imaging. One modality is the target, and the other one can be considered as the privileged modality owing to their semantic relatedness. The experiments show that our PMD is effective in VBDI (e.g. the Dice index is larger than 0.95), as well as superior to six state-of-the-art VBDI methods.

In-vitro and in-vivo imaging of coronary artery stents with Heartbeat OCT

To quantify the impact of cardiac motion on stent length measurements with Optical Coherence Tomography (OCT) and to demonstrate in vivo OCT imaging of implanted stents, without motion artefacts. The study consists of: clinical data evaluation, simulations and in vivo tests. A comparison between OCT-measured and nominal stent lengths in 101 clinically acquired pullbacks was carried out, followed by a simulation of the effect of cardiac motion on stent length measurements, experimentally and computationally. Both a commercial system and a custom OCT, capable of completing a pullback between two consecutive ventricular contractions, were employed. A 13 mm long stent was implanted in the left anterior descending branch of two atherosclerotic swine and imaged with both OCT systems. The analysis of the clinical OCT images yielded an average difference of 1.1 ± 1.6 mm, with a maximum difference of 7.8 mm and the simulations replicated the statistics observed in clinical data. Imaging with the custom OCT, yielded an RMS error of 0.14 mm at 60 BPM with the start of the acquisition synchronized to the cardiac cycle. In vivo imaging with conventional OCT yielded a deviation of 1.2 mm, relative to the length measured on ex-vivo micro-CT, while the length measured in the pullback acquired by the custom OCT differed by 0.20 mm. We demonstrated motion artefact-free OCT-imaging of implanted stents, using ECG triggering and a rapid pullback.

Contemporary practices using intravascular imaging guidance with IVUS or OCT to optimize percutaneous coronary intervention

Introduction: Angiography is routinely used to perform percutaneous coronary intervention (PCI). However, angiography has many limitations that prevent accurate assessment of coronary lesions. The development and evolution of intravascular imaging have offset the limitations of angiography. Overwhelming evidence supports intravascular imaging guidance to optimize PCI results and studies have shown that it is associated with better outcomes. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are the most commonly used modalities and both have far greater spatial resolution compared with angiography. There are advantages and disadvantages to both IVUS and OCT, and the optimal modality will depend on patient factors and indications.Areas covered: This review will summarize clinical evidence and current practices in the use of intravascular imaging in PCI. Literature review from year 2000-2019 was completed via PubMed search using keywords.Expert commentary: Intravascular imaging is an essential tool in PCI that has outcome implications, but it is still underutilized. Proper image acquisition, accurate interpretation, and correct decision-making are needed for patients to benefit from imaging-guided PCI. Training and education are essential in successful utilization of imaging technology. High-definition IVUS is likely to gain favor as there is improved image resolution without the use of contrast.

Post-stEnting assessment of Re-endothelialization with optical Frequency domain imaging aftEr Chronic Total Occlusion procedure: The PERFE-CTO Study Design and Rationale

BACKGROUND

The treatment of chronic total occlusion of coronary arteries by percutaneous coronary intervention (CTO PCI) is one of the most representative technical advances in ischemic cardiomyopathy of last decade. However, how the complex histopathological remodeling and the new techniques affect healing processes after stent implantation remains unknown.

OBJECTIVE

The objective of the PERFE-CTO study is to analyze stent coverage, malapposition and other mechanical abnormalities 3 months after CTO recanalization using intravascular imaging.

METHODS

In a French prospective interventional multicenter study, stent strut coverage, acquired malapposition and neointimal hyperplasia (NIH) proliferation will be systematically assessed with 3 months angiogram control and intracoronary optical frequency domain imaging (OFDI) after successful CTO PCI of >20 mm in length. The impact of routine systematical intracoronary imaging after these complex procedures will also be evaluated by measuring the rate of significant mechanical abnormalities (strut malapposition, edge dissection, thrombus) that was undetected by fluoroscopy alone and by complementary PCI when needed. Secondarily, these data will be compared according to clinical characteristics, antiplatelet therapy use or desobstruction technique (antegrade vs. retrograde, true lumen vs. subintima). Each patient will undergo a one-year clinical follow-up. A total of 150 analyzed CTO lesions is expected.

CONCLUSION

The PERFE-CTO study will provide essential understanding of the early history after CTO recanalization and the identification of inadequate evolution (stent thrombosis, restenosis or late delayed stent endothelization and cardiovascular outcomes) using intravascular imaging to improve long-term CTO results.

Contrast Volume and Decline in Kidney Function in Optical Coherence Tomography-Guided Percutaneous Coronary Intervention

Optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) may increase contrast volume. However, the impact of OCT-guided PCI on the decline in kidney function (DKF) in actual clinical practice remains unclear.Among 1,003 consecutive patients who underwent either OCT-guided or intravascular ultrasound (IVUS)-guided PCI in our institute, we identified 202 propensity score-matched pairs adjusted by baseline factors. The incidence of DKF was compared between the OCT-guided PCI group and the IVUS-guided PCI group. DKF was defined as an increase in serum creatinine level of ≥ 0.5 mg/dL or a relative increase of ≥ 25% over baseline within 48 hours (acute DKF) or 1 month (sustained DKF) after PCI.Baseline characteristics, including the prevalence of chronic kidney disease (54% versus 46%, P = 0.09), were comparable between the OCT- and IVUS-guided PCI groups except for the age. The contrast volume was comparable between the two groups (153 ± 56 versus 144 ± 60 mL, P = 0.09), although it was significantly greater in the OCT-guided PCI group in patients with acute coronary syndrome (ACS; 175 ± 55 versus 159 ± 43 mL, P = 0.04). The incidence of acute DKF (0.5% versus 2.5%, P = 0.22) and sustained DKF (5.0% versus 10.4%, P = 0.31) was comparable between the two groups. Multivariate analysis demonstrated that ACS (odds ratio 4.74, 95% confidence interval 2.72-8.25, P < 0.001) was a predictor of sustained DKF.Compared with IVUS-guided PCI, OCT-guided PCI did not increase the incidence of DKF in actual clinical practice, although the increased contrast volume was observed in ACS cases.

Optimization of Percutaneous Coronary Intervention Using Optical Coherence Tomography

Compared to the luminogram obtained by angiography, intravascular modalities produce cross-sectional images of coronary arteries with a far greater spatial resolution. It is capable of accurately determining the vessel size and plaque morphology. It also eliminates some disadvantages such as contrast streaming, foreshortening, vessel overlap, and angle dependency inherent to angiography. Currently, the development of its system and the visualization of coronary arteries has shown significant advancement. Of those, optical coherence tomography (OCT) makes it possible to obtain high-resolution images of intraluminal and transmural coronary structures leading to navigation of the treatment strategy before and after stent implantations. The aim of this review is to summarize the published data on the clinical utility of OCT, focusing on the use of OCT in interventional cardiology practice to optimize percutaneous coronary intervention.

Residual atherothrombotic burden after primary percutaneous coronary intervention and myocardial reperfusion-An optical frequency domain imaging study

OBJECTIVES

We aimed to assess the relationship between residual in-stent atherothrombotic burden (ATB) after primary percutaneous coronary intervention (PCI) measured by optical frequency domain imaging (OFDI) using different measurement methods and myocardial blush grade (MBG).

BACKGROUND

The impact of residual ATB after primary PCI on myocardial reperfusion remains unclear.

METHODS

We prospectively included 60 ST-elevation myocardial infarction patients pretreated with aspirin and ticagrelor. OFDI volumetric quantification using planimetry (with intervals every frame or every millimeter) and semiquantitative score were used to determine ATB. Patients were divided into two groups according to final MBG 3 or <3.

RESULTS

The mean ATB was 10.08 ± 5.21%. ATB was lower in patients with final MBG 3 compared to those with impaired MBG, regardless of the measurement method (8.15 ± 5.58 vs. 11.77 ± 4.28%; p = .007 for quantification per frame; 7.8 ± 5.19 vs. 11.07 ± 4.07%; p = .009 for quantification per mm and 11.21 ± 11.75 vs. 22.91 ± 17.35; p = .003 for the semiquantitative thrombus score, respectively).

CONCLUSION

Residual post-stenting ATB remains substantial after primary PCI in STEMI patients, even when pretreated with ticagrelor and aspirin. ATB appears as a significant correlate of suboptimal myocardial reperfusion, a known surrogate of clinical outcome.

Prospective Randomized Comparison of Fractional Flow Reserve Versus Optical Coherence Tomography to Guide Revascularization of Intermediate Coronary Stenoses: One-Month Results

Background Fractional flow reserve (FFR) and optical coherence tomography (OCT) may help both in assessment and in percutaneous coronary intervention optimization of angiographically intermediate coronary lesions. We designed a prospective trial comparing the clinical and economic outcomes associated with FFR or OCT in angiographically intermediate coronary lesions. Methods and Results Three hundred fifty patients with angiographically intermediate coronary lesions (n=446) were randomized to FFR or OCT guidance. In the FFR arm, percutaneous coronary intervention was performed if FFR was ≤0.80 aiming for a postprocedure FFR >0.90. In the OCT arm, percutaneous coronary intervention was performed if percentage of area stenosis was ≥75% or 50% to 75% with minimal lumen area <2.5 mm2 or plaque ulceration. Costs, angina frequency, and major adverse cardiac events were assessed at 1 month and at 13 months. We present early data at 1 month consistent with a prespecified analysis of secondary end points. Patients randomized to FFR, as compared with OCT, were significantly more commonly managed with medical therapy alone (67.7% versus 41.1%; P<0.001), required less contrast media (245±137 versus 280±129 mL; P=0.004), and exhibited a lower occurrence of contrast-induced acute kidney injury (1.7% versus 8.6%; P=0.034). At 1 month, in comparison to FFR, OCT was associated with increased total costs (2831±1288 versus 4292±3844 euros/patient; P<0.001) whereas occurrence of major adverse cardiac events or significant angina was similar. Conclusions In patients with angiographically intermediate coronary lesions, a functional guidance by FFR, as compared with OCT, increased the rate of patients treated with medical therapy alone. This translated into a significant reduction in administered contrast, contrast-induced acute kidney injury, and total costs at 1 month with FFR. Clinical Trial Registration URL: http://www.clinicaltrialsgov. Unique identifier: NCT01824030.

Current clinical use of intravascular ultrasound imaging to guide percutaneous coronary interventions

During the past three decades, since the invention of intravascular ultrasound (IVUS), it has become increasingly important as daily clinical applications. However, it evolved with no Japanese standards for the measurement of images, the index of percutaneous coronary intervention (PCI) procedures, and the reporting of results. Accordingly, the purpose of this review article is to provide an optimal and consistent approach to IVUS usage during PCI for clinicians and investigators.

Intracoronary Optical Coherence Tomography 2018: Current Status and Future Directions

The advent of intravascular imaging has been a significant advancement in visualization of coronary arteries, particularly with optical coherence tomography (OCT) that allows for high-resolution imaging of intraluminal and transmural coronary structures. Accumulating data support a clinical role for OCT in a multitude of clinical scenarios, including assessing the natural history of atherosclerosis and modulating effects of therapies, mechanisms of acute coronary syndromes, mechanistic insights into the effects of novel interventional devices, and optimization of percutaneous coronary intervention. In this state-of-the-art review, we provide an overview of the published data on the clinical utility of OCT, highlighting the areas that need further investigation and the current barriers for further adoption of OCT in interventional cardiology practice.

Real-Life Benefit of OCT Imaging for Optimizing PCI Indications, Strategy, and Results

Background: The aim of this study was to evaluate the benefit of standard practice Optical Coherence Tomography (OCT) imaging, as a complement to coronary angiography (CA), for optimizing the indications, strategy, and results of percutaneous coronary interventions (PCI). Methods: We retrospectively analyzed 182 patients with OCT imaging in a single tertiary center. Results: OCT use had a low prevalence (3.1% of 4256 CAs and 1.7% of 3027 PCIs). OCT was used post-CA in 71.5% and post-PCI in 28.5% of cases, mainly in acute coronary syndromes—95.6%. OCT was performed for borderline lesions in 43.4% of cases; lesion severity was reassessed as severe and led to PCI in 64.5% of them. OCT was performed for nonsignificant lesions in 17% of cases; lesion severity was reassessed as severe and led to PCI in 38.7% of them. OCT provided optimal selection for PCI strategy in 11% of cases. OCT identified suboptimal PCI results in 54% left main PCIs and in 48% bifurcation PCIs with optimal CA; PCI optimization was performed. In the only seven patients with suboptimal PCI, OCT revealed an optimal result in four cases, thus avoiding unneccessary optimization. In 27.3% of patients with post-CA OCT and PCI result “systematic” OCT control, a PCI optimization was indicated. Conclusion: OCT supplied a major benefit in 86.2% of cases, especially by identifying significant coroanry stenosis in CA borderline and nonsignificant lesions; OCT led to PCI indication in two-thirds and, respectively, one-third of these cases. In the post-PCI context, OCT led to an indication of PCI optimization in half of the complex left main and bifurcation lesions, as well as in a quarter of “systematic” post-PCI OCT controls.

The Angular Spectrum of the Scattering Coefficient Map Reveals Subsurface Colorectal Cancer

Colorectal cancer diagnosis currently relies on histological detection of endoluminal neoplasia in biopsy specimens. However, clinical visual endoscopy provides no quantitative subsurface cancer information. In this ex vivo study of nine fresh human colon specimens, we report the first use of quantified subsurface scattering coefficient maps acquired by swept-source optical coherence tomography to reveal subsurface abnormities. We generate subsurface scattering coefficient maps with a novel wavelet-based-curve-fitting method that provides significantly improved accuracy. The angular spectra of scattering coefficient maps of normal tissues exhibit a spatial feature distinct from those of abnormal tissues. An angular spectrum index to quantify the differences between the normal and abnormal tissues is derived, and its strength in revealing subsurface cancer in ex vivo samples is statistically analyzed. The study demonstrates that the angular spectrum of the scattering coefficient map can effectively reveal subsurface colorectal cancer and potentially provide a fast and more accurate diagnosis.

Comparison of clinical outcomes between intravascular optical coherence tomography-guided and angiography-guided stent implantation: A meta-analysis of randomized control trials and systematic review

OBJECTIVE

This systematic review was designed to evaluate the overall efficacy of optical coherence tomography (OCT)-guided implantation versus angiography-guided for percutaneous coronary intervention.

METHODS

The following electronic databases, such as CENTRAL, PubMed, Cochrane, and EMBASE were searched for systematic reviews to investigate OCT-guided and angiography-guided implantation. We measured the following 7 parameters in each patient: stent thrombosis, cardiovascular death, myocardial infarction, major adverse cardiac events (MACE), target lesion revascularization (TLR), target vessel revascularization (TVR), all-cause death.

RESULTS

In all, 11 studies (6 RCTs and 5 observational studies) involving 4026 subjects were included, with 1903 receiving intravascular ultrasound-guided drug-eluting stent (DES) implantation and 2123 using angiography-guided DES implantation. With regard to MACE, MT, TLR, TVR, stent thrombosis and all-cause death, the group of OCT-guided implantation had no significant statistical association with remarkably improved clinical outcomes. However, its effect on cardiovascular death has a significant statistical difference in angiography-guided implantation group.

CONCLUSION

In the present pool analysis, OCT-guided DES implantation showed a tendency toward improved clinical outcomes compared to angiography-guided implantation. More eligible randomized clinical trials are warranted to verify the findings and to determine the beneficial effect of OCT-guidance for patients.

Safety and efficacy of frequency-domain optical coherence tomography in evaluating and treating intermediate coronary lesions

AIM

To establish whether frequency-domain optical coherence tomography (FD-OCT) is safe and effective in the evaluation and treatment of angiographically-intermediate coronary lesions (ICL)

METHODS

Sixty-four patients with 2-dimensional quantitative coronary angiography (2D-QCA) demonstrating ICL were included. OCT imaging was performed. According to predetermined OCT criteria, patients were assigned to either of 2 groups: OCT-guided percutaneous coronary intervention (PCI) or OCT-guided optimal medical therapy (OMT). The primary efficacy endpoint was to demonstrate the superiority and higher accuracy of FD-OCT compared to 2D-QCA in evaluating stenosis severity in patients with ICL. The primary safety endpoint was the incidence of 30-d major adverse cardiac events (MACE). Secondary endpoints included MACE at 12 mo and other clinical events.

RESULTS

Analysis of the primary efficacy endpoint demonstrates that 2D-QCA overestimates the stenosis severity of ICL in both the OCT-guided PCI and OMT groups, proving FD-OCT to be superior to and more precise than 2D-QCA in treating this subset of lesions. The primary safety endpoint was fully met with the incidence of 30-d MACE being nil in both the OCT-guided PCI and OCT-guided OMT groups. Incidences of secondary endpoints were found to be low in both arms, the only exception being the relatively high incidence of recurrent episodes of angina which was, however, very similar in the 2 groups.

CONCLUSION

FD-OCT is safe and effective in the evaluation and treatment of ICL. Larger studies are needed to firmly establish the efficacy and safety of FD-OCT in treating ICL across all coronary artery disease population subgroups.

Appropriate use criteria for optical coherence tomography guidance in percutaneous coronary interventions : Recommendations of the working group of interventional cardiology of the Netherlands Society of Cardiology

Introduction

Optical coherence tomography (OCT) enables detailed imaging of the coronary wall, lumen and intracoronary implanted devices. Responding to the lack of specific appropriate use criteria (AUC) for this technique, we conducted a literature review and a procedure for appropriate use criteria.

Methods

Twenty-one of all 184 members of the Dutch Working Group on Interventional Cardiology agreed to evaluate 49 pre-specified cases. During a meeting, factual indications were established whereupon members individually rated indications on a 9-point scale, with the opportunity to substantiate their scoring.

Results

Twenty-six indications were rated ‘Appropriate’, eighteen indications ‘May be appropriate’, and five ‘Rarely appropriate’. Use of OCT was unanimously considered ‘Appropriate’ in stent thrombosis, and ‘Appropriate’ for guidance in PCI, especially in distal left main coronary artery and proximal left anterior descending coronary artery, unexplained angiographic abnormalities, and use of bioresorbable vascular scaffold (BVS). OCT was considered ‘Rarely Appropriate’ on top of fractional flow reserve (FFR) for treatment indication, assessment of strut coverage, bypass anastomoses or assessment of proximal left main coronary artery.

Conclusions

The use of OCT in stent thrombosis is unanimously considered ‘Appropriate’ by these experts. Varying degrees of consensus exists on the appropriate use of OCT in other settings.

Electronic supplementary material

The online version of this article (10.1007/s12471-018-1143-z) contains supplementary material, which is available to authorized users.

Clinical significance of optical coherence tomography-guided angioplasty on treatment selection

The present study aimed to observe whether optical coherence tomography (OCT)-guided angioplasty is able to provide useful clinical information beyond that obtained by angiography as well as provide recommendations for physicians that may improve treatment selection. This prospective study included 83 patients with coronary artery disease (>18 years) undergoing coronary angiography (CAG) for ST-elevation myocardial infarction (n=13), non-ST-elevation myocardial infarction (n=19), stable angina (n=22), unstable angina (n=10), silent ischemia (n=11), or elective percutaneous coronary intervention (n=8). Following the initial CAG (CAG-pre), the patients underwent OCT before angioplasty (OCT-pre, 24 patients), after angioplasty (OCT-post, 22 patients), or both (37 patients). The thrombus burden, calcification and plaque dissection or rupture were compared between the OCT-pre and CAG-pre recordings. Following angioplasty, stent malapposition, suboptimal stent deployment, suboptimal stent lesion coverage, and edge dissection were compared between OCT-post and CAG-post alone. Among the 83 patients, 45.7% had single-vessel and 54.3% had multiple-vessel disease. OCT pre- and post-angioplasty revealed significantly more information on the procedure than CAG alone. This clinical information changed the clinical strategies in 41/83 (49.4%) patients, including 58 modifications of therapeutic strategy (69.9%, 58/83): Thrombus aspiration in 2 cases (2.4%), administration of glycoprotein IIb/IIIa inhibitors in 8 cases (9.6%), additional balloon inflation in 23 cases (27.7%), additional stent implantation in 17 cases (20.5%), avoiding stent implantation in 4 cases (4.8%), collateral intervention in 2 cases (2.4%), and guidewire reposition in 2 cases (2.4%). In conclusion, OCT-pre and OCT-post provided additional clinical information beyond that obtained by angiography alone, which resulted in modification of the treatment strategies in half of the included patients.