Early Strut Coverage in Patients Receiving Drug-Eluting Stents and its Implications for Dual Antiplatelet Therapy: A Randomized Trial.JACC Cardiovasc Imaging. 2018;11:1810-1819. [PMID: 29454763 DOI: 10.1016/j.jcmg.2017.12.014]

Early vascular healing after neXt-generation drug-eluting stent implantation in Patients with non-ST elevation acute Coronary syndrome: a randomized optical coherence Tomography imaging study (EXPECT)

Early vascular healing after drug-eluting stent (DES) implantation is associated with better outcomes and lower incidence of in-stent thrombosis. To examine vascular healing response in patients with non-ST elevation acute coronary syndrome (NSTE-ACS) undergoing percutaneous coronary intervention (PCI) guided by optical coherence tomography (OCT) versus angiography alone. Sixty patients were randomized 1:1:1 to OCT-guided PCI with 3-month OCT follow-up (O3 group, n = 20), angiography-guided PCI with 3-month OCT follow-up (A3 group, n = 20), or angiography-guided PCI with 6-month OCT follow-up (A6 group, n = 20). The primary endpoint was the proportion of covered struts at 3- or 6-month follow-up. The proportion of covered struts in the O3 group was significantly higher than in the A3 group (95.2% vs. 92.3%, p < 0.001), but lower than in the A6 group (95.2% vs. 97.4%, p < 0.001). The O3 group had a lower proportion of incomplete strut apposition (ISA) than the A3 group (0.46% vs. 0.76%, p = 0.006), and higher than the A6 group (0.46% vs. 0.27%, p = 0.018) at follow-up. The optimal cut-off value of ISA after implantation of DES for predicting stent coverage at 3 and 6-month follow-up was 200 μm and 308 μm, respectively. Only one patient experienced target lesion revascularization in the A3 group during a 3-year clinical follow-up. In patients with NSTE-ACS undergoing PCI with DES, OCT guidance achieved higher strut coverage compared with angiography guidance at 3-month follow-up. However, the difference in the strut coverage between the OCT-guided group and the angiography-guided group at 6 months indicates that the degree of endothelialization may be more time-dependent instead of invasive device guidance.

Emerging Hybrid Intracoronary Imaging Technologies and Their Applications in Clinical Practice and Research

Intravascular ultrasound and optical coherence tomography are used with increasing frequency for the care of coronary patients and in research studies. These imaging tools can identify culprit lesions in acute coronary syndromes, assess coronary stenosis severity, guide percutaneous coronary intervention (PCI), and detect vulnerable plaques and patients. However, they have significant limitations that have stimulated the development of multimodality intracoronary imaging catheters, which provide improvements in assessing vessel wall pathology and guiding PCI. Prototypes combining 2 or even 3 imaging probes with complementary attributes have been developed, and several multimodality systems have already been used in patients, with near-infrared spectroscopy intravascular ultrasound-based studies showing promising results for the identification of high-risk plaques. Moreover, postmortem histology studies have documented that hybrid imaging catheters can enable more accurate characterization of plaque morphology than standalone imaging. This review describes the evolution in the field of hybrid intracoronary imaging; presents the available multimodality catheters; and discusses their potential role in PCI guidance, vulnerable plaque detection, and the assessment of endovascular devices and emerging pharmacotherapies targeting atherosclerosis.

Widespread Use of Imaging-Guided PCI in Asia: Time for Extended Application

In recent years, a wealth of clinical data has emerged regarding intravascular imaging involving either intravascular ultrasound or optical coherence tomography. This surge in data has propelled the adoption of intravascular imaging-guided percutaneous coronary intervention (PCI) in daily clinical practice. The findings of current randomized clinical trials regarding imaging guidance have lent strong support to the benefits of intravascular imaging-guided PCI. This holds especially true for the diagnosis and treatment of complex lesions, such as left main disease, diffuse long lesions, chronic total occlusion, severely calcified lesions, bifurcations, and in-stent restenosis, as well as in high-risk patients such as those with acute myocardial infarction or chronic kidney disease. During intravascular imaging-guided PCI, operators attempt to achieve stent optimization for maximized benefits of imaging guidance. This paper provides a comprehensive review on the updated clinical data of intravascular imaging-guided PCI and intravascular ultrasound/optical coherence tomography-derived stent optimization criteria.

Assessment of Effectiveness of the Algorithm for Automated Quantitative Analysis of Metallic Strut Tissue Short-Term Coverage with Intravascular Optical Coherence Tomography

Background: Due to its high resolution, optical coherence tomography (OCT) is the most suitable modality for neointimal coverage assessments. Evaluation of stent healing seems crucial to accurately define their safety profile since delayed healing is connected with stent thrombosis. This study aimed to present an algorithm for automated quantitative analysis of stent strut coverage at the early stages of vessel healing in intravascular OCT. Methods: A set of 592 OCT frames from 24 patients one month following drug-eluting stent implantation was used to assess the algorithm's effectiveness. Struts not covered on any side or covered but only on one side were categorized as uncovered. The algorithm consists of several key steps: preprocessing, vessel lumen segmentation, automatic strut detection, and measurement of neointimal thickness. Results: The proposed algorithm proved its efficiency in lumen and stent area estimation versus manual reference. It showed a high positive predictive value (PPV) (89.7%) and true positive rate (TPR) (91.4%) in detecting struts. A qualitative assessment for covered and uncovered struts was characterized by high TPR (99.1% and 80%, respectively, for uncovered and covered struts) and PPV (77.3% and 87%). Conclusions: The proposed algorithm demonstrated good agreement with manual measurements. Automating the stent coverage assessment might facilitate imaging analysis, which might be beneficial in experimental and clinical settings.

Role of intravascular ultrasound and optical coherence tomography in intracoronary imaging for coronary artery disease: a systematic review

Coronary angiography has long been the standard for coronary imaging, but it has limitations in assessing vessel wall anatomy and guiding percutaneous coronary intervention (PCI). Intracoronary imaging techniques like intravascular ultrasound (IVUS) and optical coherence tomography (OCT) can overcome these limitations. IVUS uses ultrasound and OCT uses near-infrared light to visualize coronary pathology in unique ways due to differences in temporal and spatial resolution. These techniques have evolved to offer clinical utility in plaque characterization and vessel assessment during PCI. Meta-analyses and adjusted observational studies suggest that both IVUS and OCT-guided PCI correlate with reduced cardiovascular risks compared to angiographic guidance alone. While IVUS demonstrates consistent clinical outcome benefits, OCT evidence is less robust. IVUS has progressed from early motion detection to high-resolution systems, with smaller compatible catheters. OCT utilizes near infrared light to achieve unparalleled resolutions, but requires temporary blood clearance for optimal imaging. Enhanced visualization and guidance make IVUS and OCT well-suited for higher risk PCI in patients with diabetes and chronic kidney disease by allowing detailed visualization of complex lesions and ensuring optimal stent deployment and positioning in PCI for patients with type 2 diabetes and chronic kidney disease, improving outcomes. IVUS and recent advancements in zero- and low-contrast OCT techniques can reduce nephrotoxic contrast exposure, thus helping to minimize PCI complications in these high-risk patient groups. IVUS and OCT provide valuable insights into coronary pathophysiology and guide interventions precisely compared to angiography alone. Both have comparable clinical outcomes, emphasizing the need for tailored imaging choices based on clinical scenarios. Continued refinement and integration of intravascular imaging will likely play a pivotal role in optimizing coronary interventions and outcomes. This systematic review aims to delve into the nuances of IVUS and OCT, highlighting their strengths and limitations as PCI adjuncts.

Clinical impact of OCT-derived suboptimal stent implantation parameters and definitions

AIMS

Despite growing evidence supporting the clinical utility of optical coherence tomography (OCT) guidance during percutaneous coronary interventions (PCIs), there is no common agreement as to the optimal stent implantation parameters that enhance clinical outcome.

METHODS AND RESULTS

We retrospectively examined the predictive accuracy of suboptimal stent implantation definitions proposed from the CLI-OPCI II, ILUMIEN-IV OPTIMAL PCI, and FORZA studies for the long-term risk of device-oriented cardiovascular events (DoCE) in the population of large all-comers CLI-OPCI project. A total of 1020 patients undergoing OCT-guided drug-eluting stent implantation in the CLI-OPCI registry with a median follow-up of 809 (quartiles 414-1376) days constituted the study population. According to CLI-OPCI II, ILUMIEN-IV OPTIMAL PCI, and FORZA criteria, the incidence of suboptimal stent implantation was 31.8%, 58.1%, and 57.8%, respectively. By multivariable Cox analysis, suboptimal stent implantation criteria from the CLI-OPCI II [hazard ratio 2.75 (95% confidence interval 1.88-4.02), P < 0.001] and ILUMIEN-IV OPTIMAL PCI [1.79 (1.18-2.71), P = 0.006] studies, but not FORZA trial [1.11 (0.75-1.63), P = 0.597], were predictive of DoCE. At long-term follow-up, stent edge disease with minimum lumen area <4.5 mm2 [8.17 (5.32-12.53), P < 0.001], stent edge dissection [2.38 (1.33-4.27), P = 0.004], and minimum stent area <4.5 mm2 [1.68 (1.13-2.51), P = 0.011] were the main OCT predictors of DoCE.

CONCLUSION

The clinical utility of OCT-guided PCI might depend on the metrics adopted to define suboptimal stent implantation. Uncovered disease at the stent border, stent edge dissection, and minimum stent area <4.5 mm2 were the strongest OCT associates of stent failure.

Faster smooth muscle cell coverage in ultrathin-strut drug-eluting stent leads to earlier re-endothelialization

Background: The ultrathin-strut drug-eluting stent (DES) has shown better clinical results than thin- or thick-strut DES. We investigated if re-endothelialization was different among three types of DES: ultrathin-strut abluminal polymer-coated sirolimus-eluting stent (SES), thin-strut circumferential polymer-coated everolimus-eluting stent (EES), and thick-strut polymer-free biolimus-eluting stent (BES) to gain insight into the effect of stent design on promoting vascular healing. Methods: After implanting three types of DES in the coronary arteries of minipigs, we performed optical coherence tomography (OCT) at weeks 2, 4, and 12 (n = 4, each). Afterward, we harvested the coronary arteries and performed immunofluorescence for endothelial cells (ECs), smooth muscle cells (SMCs), and nuclei. We obtained 3D stack images of the vessel wall and reconstructed the en face view of the inner lumen. We compared re-endothelialization and associated factors among the different types of stents at different time points. Results: SES showed significantly faster and denser re-endothelialization than EES and BES at weeks 2 and 12. Especially in week 2, SES elicited the fastest SMC coverage and greater neointimal cross-sectional area (CSA) compared to EES and BES. A strong correlation between re-endothelialization and SMC coverage was observed in week 2. However, the three stents did not show any difference at weeks 4 and 12 in SMC coverage and neointimal CSA. At weeks 2 and 4, SMC layer morphology showed a significant difference between stents. A sparse SMC layer was associated with denser re-endothelialization and was significantly higher in SES. Unlike the sparse SMC layer, the dense SMC layer did not promote re-endothelialization during the study period. Conclusion: Re-endothelialization after stent implantation was related to SMC coverage and SMC layer differentiation, which were faster in SES. Further investigation is needed to characterize the differences among the SMCs and explore methods for increasing the sparse SMC layer in order to improve stent design and enhance safety and efficacy.

Intravascular Imaging During Percutaneous Coronary Intervention: JACC State-of-the-Art Review

Coronary angiography has historically served as the gold standard for diagnosis of coronary artery disease and guidance of percutaneous coronary intervention (PCI). Adjunctive use of contemporary intravascular imaging (IVI) technologies has emerged as a complement to conventional angiography-to further characterize plaque morphology and optimize the performance of PCI. IVI has utility for preintervention lesion and vessel assessment, periprocedural guidance of lesion preparation and stent deployment, and postintervention assessment of optimal endpoints and exclusion of complications. The role of IVI in reducing major adverse cardiac events in complex lesion subsets is emerging, and further studies evaluating broader use are underway or in development. This paper provides an overview of currently available IVI technologies, reviews data supporting their utilization for PCI guidance and optimization across a variety of lesion subsets, proposes best practices, and advocates for broader use of these technologies as a part of contemporary practice.

Optical coherence tomography and coronary revascularization: from indication to procedural optimization

Angiography alone is the most commonly used imaging modality for guidance of percutaneous coronary interventions. Angiography is limited, however, by several factors, including that it only portrays a low resolution, two-dimensional outline of the lumen and does not inform on plaque composition and functional stenosis severity. Optical coherence tomography (OCT) is an intracoronary imaging technique that has superior spatial resolution compared to all other imaging modalities. High-resolution imaging of the vascular wall enables precise measurement of vessel wall and luminal dimensions, more accurately informing about the anatomic severity of epicardial stenoses, and also provides input for computational models to assess functional severity. The very high-resolution images also permit plaque characterization that may be informative for prognostication. Moreover, periprocedural imaging provides valuable information to guide lesion preparation, stent implantation and to evaluate acute stent complications for which iterative treatment might reduce the occurrence of major adverse stent events. As such, OCT represent a potential future all-in-one tool that provides the data necessary to establish the indications, procedural planning and optimization, and final evaluation of percutaneous coronary revascularization.

Identification of post-procedural optical coherence tomography findings associated with the 1-year vascular response evaluated by coronary angioscopy

Optical coherence tomography (OCT) provides higher resolution intravascular imaging and allows detailed evaluations of stent implantation sites post-percutaneous coronary intervention (PCI). Coronary angioscopy (CAS) can evaluate the vascular response after drug-eluting stent (DES) implantation. The post-PCI OCT findings that are associated with the CAS 1-year vascular response have not been known. We enrolled 168 lesions from 119 patients who underwent OCT-guided PCI using DES and follow-up CAS observation at 1 ± 0.5 year from August 2012 to December 2019. Outcome measures were sufficient neointimal coverage (NIC) defined as stent struts embedded in the neointima, subclinical intrastent thrombus, and vulnerable stented segments defined as those with angioscopic yellow or intensive yellow color 1 year after PCI. We identified the post-PCI OCT findings associated with these CAS findings. Sufficient NIC, subclinical intrastent thrombus, and vulnerable stented segment were detected in 85 lesions (51%), 47 lesions (28%), and 54 lesions (32%), respectively. A multivariate analysis demonstrated that malapposed struts were negatively associated with sufficient NIC (odds ratio 0.87; 95% CI 0.76-0.99; p = 0.029). However, no specific OCT findings immediately after PCI were associated with subclinical intrastent thrombus or vulnerable stented segment. Malapposition immediately after PCI was negatively associated with sufficient NIC at 1 year even without associations between post-PCI OCT findings and subclinical intrastent thrombus or vulnerable stented segment.

Early vascular healing after neXt-generation drug-eluting stent implantation in Patients with non-ST Elevation acute Coronary syndrome based on optical coherence Tomography guidance and evaluation (EXPECT): study protocol for a randomized controlled trial

Background

There is limited evidence about vessel wall healing response following implantation of next-generation drug-eluting stents (DES) in patients admitted with a non-ST elevation acute coronary syndrome (NSTE-ACS). Cumulative data indicate that optical coherence tomography (OCT) imaging can optimize percutaneous coronary intervention results and expedite stent endothelialization in the general population but there is lack of data in NSTE-ACS patients.

Methods

The EXPECT study is an investigator-initiated, prospective, randomized trial to assess early vascular healing response following next-generation DES implantation in patients admitted with NSTE-ACS based on OCT guidance and evaluation. Sixty patients are randomized at 1:1:1 ratio to OCT-guided percutaneous coronary intervention (PCI) with 3-month follow-up OCT imaging (O3 group, n = 20), to angiography-guided PCI with 3-month follow-up OCT imaging (A3 group, n = 20) and to angiography-guided PCI with 6-month follow-up OCT imaging (A6 group, n = 20). The primary endpoint of the study is stent strut coverage rate at 3- or 6- month follow-up in the studied groups. The secondary endpoints of the study include OCT imaging endpoints, clinical endpoints, and molecular biology endpoints at the different time points. The clinical endpoints comprised of major cardiovascular adverse events and individual components. The molecular biology endpoints comprised of lipid levels and the levels of inflammatory indicators.

Discussion

The findings of the EXPECT study are anticipated to provide novel insights into vessel wall healing in NSTE-ACS population following implantation of next-generation DES, underscore the value of OCT imaging in expediting strut coverage in this setting, and explore the potential of an early discontinuation of dual antiplatelet therapy (DAPT) in this population.

Clinical Trial Registration

ClinicalTrials.gov, NCT04375319.

Determinants and long-term outcomes of largely uncovered struts in thin-struts drug-eluting stents assessed by optical coherence tomography

BACKGROUND

Uncovered struts are a determinant of stent failure. The impact of plaque composition and procedural factors on the occurrence, evolution, and outcomes of uncovered struts in a high-risk setting has not been investigated.

OBJECTIVE

To investigate the determinants and long-term clinical impact of largely uncovered struts (LUS) in thin-struts drug-eluting stents (DES) implanted in complex lesions by intracoronary optical coherence tomography (OCT).

METHODS

Ninety patients with multivessel disease undergoing staged complete revascularization were randomly assigned to bioabsorbable or durable polymer DES. OCT were serially performed during the index procedure, at 3- and 18-month follow-up, and analyzed by an independent core lab. Struts were defined uncovered by OCT if no tissue was visible above the struts. LUS were defined as ≥30% of uncovered struts at 3-month follow-up. Clinical outcomes were the occurrence of target vessel failure (TVF) and major adverse cardiac and cerebrovascular events (MACCE) at 5-year follow-up.

RESULTS

LUS occurred in 31 patients (34.4%) regardless of stent platform. At 5 years, no differences were observed in the rate of TVF (12.7% vs. 13.4%; p = 0.91) and MACCE (23.9% vs. 24.9%; p = 0.88) between the two groups. At multivariate logistic regression, plaque rupture, mean lumen diameter, proximal reference vessel area, and maximum stent deployment pressure were independent predictors of LUS.

CONCLUSIONS

LUS are a frequent finding in complex coronary lesions treated with thin-struts DES, especially in the presence of plaque rupture. However, in this study, no significant safety signal related to LUS emerged in long-term follow-up.

Intravascular Imaging for Percutaneous Coronary Intervention Guidance and Optimization: The Evidence for Improved Patient Outcomes

As of this writing, there have been approximately 24 randomized controlled trial publications, 32 meta-analyses, and 85 registries comparing intravascular ultrasound (IVUS) or optical coherence tomography (OCT) versus angiography-guided drug-eluting stent implantation (or IVUS versus OCT guidance). Although in specific clinical scenarios IVUS or OCT may be preferred, in most drug-eluting stent implantation procedures, either intravascular ultrasound or OCT can be used safely, efficiently, effectively, and interchangeably and will improve patient outcomes compared with stent implantation procedures performed just with angiography guidance.

Optical coherence tomography in coronary atherosclerosis assessment and intervention

Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing with the rapid progression of atherosclerosis. Accurate detection by OCT of sequelae from percutaneous coronary interventions that might be missed by angiography could improve clinical outcomes. In addition, OCT has become an essential diagnostic modality for myocardial infarction with non-obstructive coronary arteries. Insight into neoatherosclerosis from OCT could improve our understanding of the mechanisms of very late stent thrombosis. The appropriate use of OCT depends on accurate interpretation and understanding of the clinical significance of OCT findings. In this Review, we summarize the state of the art in cardiac OCT and facilitate the uniform use of this modality in coronary atherosclerosis. Contributions have been made by clinicians and investigators worldwide with extensive experience in OCT, with the aim that this document will serve as a standard reference for future research and clinical application.

Rates of Intracoronary Imaging Optimization in Contemporary Percutaneous Coronary Intervention: A Report From the BMC2 Registry

BACKGROUND

Intracoronary imaging (ICI) during percutaneous coronary intervention (PCI) improves outcomes, yet hospital- and physician-level variabilities in ICI and its impact on ICI use in contemporary PCI remain unknown. This study was performed to evaluate hospital- and physician-level use of ICI to optimize PCI.

METHODS

Using data from a large statewide registry, patients undergoing PCI between July 2019 and March 2021 were studied. The primary measure of interest was ICI (intravascular ultrasound or optical coherence tomography) optimization during PCI. A fitted hierarchical Bayesian model identified variables independently associated with ICI optimization. The performing hospital and physician were included as random effects in the model.

RESULTS

Among 48 872 PCIs, ICI optimization was performed in 8094 (16.6%). Median [interquartile range] hospital- and physician-level frequencies of ICI were 8.8% [3.1%, 16.0%] and 6.1% [1.1%, 25.0%], respectively. Bayesian modeling identified left main PCI (adjusted odds ratio [aOR], 4.41; 95% credible interval [3.82, 5.10]), proximal left anterior descending artery PCI (aOR, 2.28 [2.00, 2.59]), PCI for in-stent restenosis (aOR, 1.55 [1.40, 1.72]), and surgical consult prior to PCI (aOR, 1.21 [1.07, 1.37]) as independent predictors of ICI optimization. The hospital-level median odds ratio, an estimate of the contribution of inter-hospital variability in odds of ICI use, was 3.48 (2.64, 5.04). Physician-level median odds ratio was 3.81 (3.33, 4.45).

CONCLUSIONS

Substantial hospital- and physician-level variation in ICI was observed. Except for performance of left main PCI, the hospital and physician performing the PCI were more strongly associated with ICI optimization than any patient or procedural factors.

Optimising PCI by Intracoronary Image-guidance

Evidence to support the use of intracoronary imaging (ICI) in guiding percutaneous coronary intervention (PCI) is growing, with observational and randomized controlled trials demonstrating a benefit in acute procedural and clinical outcomes. ICI provides an opportunity to guide PCI, detailing the nature of the coronary disease, potentially influencing lesion preparation and stent selection. Following stent deployment, ICI offers a detailed assessment of lesion coverage, associated vessel trauma and stent expansion. Consensus statements have emphasized the role of ICI and detailed the parameters of stent optimization. However, intracoronary imaging is not adopted widely yet. Significant global differences in the uptake of ICI have been reported, with the vast majority of PCI being angiographically-guided. The three major barriers to the implementation of ICI include, in order of impact, prohibitive cost, prolongation of procedure time and local regulatory issues for use. However, it is our belief that a lack of education and the associated challenges of ICI interpretation provide the greatest barrier to adoption. We hope that this review of the role of ICI in PCI optimization will provide a platform for PCI operators to gain confidence in the utilization of ICI to enhance outcomes for their patients.

Can an ultrathin strut stent design and a polymer free, proendothelializing probucol matrix coating improve early strut healing? The FRIENDLY-OCT trial. An intra-patient randomized study with OCT, evaluating early strut coverage of a novel probucol coated polymer-free and ultra-thin strut sirolimus-eluting stent compared to a biodegradable polymer sirolimus-eluting stent

BACKGROUND

incomplete strut coverage determines the risk of stent thrombosis in the first months after stent implantation.

AIMS

To evaluate the potential better early healing of a novel probucol coated polymer free ultra-thin strut sirolimus eluting stent (PF-SES). [Clinical trial unique identifier: NCT02785237].

METHODS

Patients with two (angiographically similar) lesions with clinical indication for PCI were enrolled. The investigated stent was compared to a thin strut, bioresorbable polymer, sirolimus eluting stent (BP-SES). Every patient received both stents, one in each lesion, assigned in a randomized sequence. OCT was systematically performed at 3 months. Primary end point was the difference in the proportion of covered struts at 3 months (defined as ≥20 μm of tissue coverage). Secondary end points included differences in percentage of uncovered struts (0 μm coverage), mean strut coverage thickness, and malapposed struts' coverage proportion. Major adverse cardiac events (cardiac death, myocardial infarction, target lesion revascularization, and definite or probable stent thrombosis) at 12 months were also evaluated.

RESULTS

70 patients were included. At 3 months, a consistent and significantly higher strut coverage rate (≥20 μm) was observed in PF-SES as compared to BP-SES, both for well apposed (87.3% versus 79.1%, p < 0.001) and malapposed struts (50.4% vs 37.8%, p 0.00). Uncoverage rate (0 μm) was also significantly lower for the PF-SES (3.1% vs 5.3%, p < 0.001). There were no differences in clinical endpoints.

CONCLUSION

The probucol coated non-polymeric ultra-thin strut sirolimus eluting stent showed a significantly better early strut coverage at 3 months.

Optical coherence tomography versus angiography guided magnesium bioresorbable scaffold implantation in NSTEMI patients

BACKGROUND

The purpose of a bioresorbable scaffold (BRS) is to provide radial support during coronary healing. In this study, coronary artery healing after optical coherence tomography (OCT)- versus angiography-guided magnesium BRS (MBRS) implantation in patients with non-ST-segment-elevation myocardial infarction (NSTEMI) is compared.

METHODS

75 patients were randomized 1:1 to OCT- or angiography-guided implantation of a MBRS with protocolled pre- and post-dilation. In the OCT-guided group, prespecified criteria indicating additional intervention were (1) scaffold under-expansion, (2) strut malapposition, (3) edge dissection, and (4) residual stenosis at distal or proximal reference segments. The primary endpoint was OCT-derived healing stage at 6 months.

RESULTS

At 6 months, there was no difference in average healing stage between OCT- and angiography-guided intervention (4.6 [interquartile range (IQR): 4.5-4.7] versus 4.5 [IQR: 4.3-4.7]; p = 0.54). The MBRSs were completely resolved in 77.0% [IQR: 68.5-85.5] versus 76.5% [IQR: 67.9-85.5]; (p = 0.97). Minimal lumen area (MLA) was reduced at 6 months in both the OCT- (32.3%; p < 0.01) and the angiography-guided group (21.3%; p < 0.01), however OCT-guided implantation was associated with a greater reduction of total lumen volume (-27.1 ± 32.5 mm³ versus -5.0 ± 32.9 mm³; p < 0.01) and MLA (-2.3 ± 1.6 mm² vs. -1.4 ± 1.4 mm²; p = 0.02).

CONCLUSIONS

In NSTEMI patients, OCT-guidance with protocolled pre- and post-dilation of MBRS implantation showed similar healing pattern at 6 months compared to angiography-guidance alone.

CLINICAL TRIAL REGISTRATION

The Coronary Artery Healing Process after Optical Coherence Tomography Guided Percutaneous Coronary Intervention with Magmaris Bioresorbable Scaffold in Patients with Non-ST-Segment-Elevation Myocardial Infarction: (HONEST) trial is registered with ClinicalTrials.gov, NCT03016624.

Stent visualization methods to guide percutaneous coronary interventions and assess long-term patency

Evaluation of acute percutaneous coronary intervention (PCI) results and long-term follow-up remains challenging with ongoing stent designs. Several imaging tools have been developed to assess native vessel atherosclerosis and stent expansion, improving overall PCI results and reducing adverse cardiac events. Quantitative coronary analysis has played a crucial role in quantifying the extent of coronary artery disease and stent results. Digital stent enhancement methods have been well validated and improved stent strut visualization. Intravascular imaging remains the gold standard in PCI guidance but adds costs and time to the procedure. With a recent shift towards non-invasive imaging assessment and coronary computed tomography angiography imaging have shown promising results. We hereby review novel stent visualization techniques used to guide PCI and assess stent patency in the modern PCI era.

One-year performance of thin-strut cobalt chromium sirolimus-eluting stent versus thicker strut stainless steel biolimus-eluting coronary stent: a propensity-matched analysis of two international all-comers registries

OBJECTIVES

Recent improvements in coronary stent design have focussed on thinner struts, different alloys and architecture, more biocompatible polymers, and shorter drug absorption times. This study evaluates safety and efficacy of a newer generation thin-strut cobalt chromium sirolimus-eluting coronary stent (SES, Ultimaster) in comparison with a second-generation thicker strut stainless steel biolimus-eluting stent (BES, Nobori) in percutaneous coronary intervention (PCI) practice.

METHODS

A propensity score analysis was performed to adjust for differences in baseline characteristics of 8137 SES patients and 2738 BES patients of two PCI registries (e-Ultimaster and NOBORI 2). An independent clinical event committee adjudicated all endpoint-related adverse events.

RESULTS

The use of SES, as compared with BES was associated with a significantly lower rate of myocardial infarction (MI) (1.2% vs 2.2%; P = 0.0006) and target vessel-related MI (1.1% vs 1.8%; P = 0.002) at 1 year. One-year composite endpoints of all predefined endpoints were lower in patients undergoing SES implantation (target lesion failure: 3.2% vs 4.1%; P = 0.03, target vessel failure: 3.7% vs 5.0%; P = 0.003, patient-oriented composite endpoint 5.7% vs 6.8%; P = 0.03). No significant differences between SES and BES were observed in all-cause death (2.0% vs 1.6%; P = 0.19), cardiac death (1.2% vs 1.2%; P = 0.76) or stent thrombosis (0.6% vs 0.8%; P = 0.43).

CONCLUSIONS

These findings suggest an improved clinical safety and efficacy of a newer generation thin-strut SES as compared with a second-generation thicker strut BES.

Antithrombotic therapy after percutaneous coronary intervention of bifurcation lesions

Coronary bifurcations exhibit localised turbulent flow and an enhanced propensity for atherothrombosis, platelet deposition and plaque rupture. Percutaneous coronary intervention (PCI) of bifurcation lesions is associated with an increased risk of thrombotic events. Such risk is modulated by anatomical complexity, intraprocedural factors and pharmacological therapy. There is no consensus on the appropriate PCI strategy or the optimal regimen and duration of antithrombotic treatment in order to decrease the risk of ischaemic and bleeding complications in the setting of coronary bifurcation. A uniform therapeutic approach meets a clinical need. The present initiative, promoted by the European Bifurcation Club (EBC), involves opinion leaders from Europe, America, and Asia with the aim of analysing the currently available evidence. Although mainly derived from small dedicated studies, substudies of large trials or from authors' opinions, an algorithm for the optimal management of patients undergoing bifurcation PCI, developed on the basis of clinical presentation, bleeding risk, and intraprocedural strategy, is proposed here.

Early coronary healing in ST segment elevation myocardial infarction: sirolimus-eluting stents vs. drug-coated balloons after bare-metal stents. The PEBSI-2 optical coherence tomography randomized study

OBJECTIVES

Drug-coated balloons (DCBs) have theoretical advantages over drug-eluting stents (DESs) to facilitate stent healing. We studied whether, in patients undergoing primary coronary interventions (pPCIs), a strategy of DCB after bare-metal stent improves early healing as determined by optical coherence tomography (OCT) compared with new-generation DES.

METHODS

pPCI patients were randomized (1:1) to treatment with new-generation sirolimus-eluting stents (DES group) or DCB-strategy. Vessel healing was assessed by OCT at 90 days.

RESULTS

Fifty-three patients were randomized (26 DES vs. 27 DCB). At 90 days, both strategies showed a low rate of uncovered struts (3.2 vs. 3.2%, P = 0.64) and a very high and similar rate of covered and apposed struts (96.6 vs. 96.1%, respectively; P = 0.58). However, DCB group had a significantly lower rate of major coronary evaginations (68 vs. 37%, P = 0.026), and more frequently developed a thin homogeneous neointimal layer (20 vs. 70.4%, P = 0.001) suggesting distinct superior healing at 3 months compared to DES.

CONCLUSIONS

In pPCI both, sirolimus-DES and DCB-strategy, provide excellent strut coverage at 3 months. However, DCB ensures more advanced and optimal stent healing compared to sirolimus-DES. Further research is needed to determine whether, in patients undergoing pPCI, DCB offers superior long-term clinical and angiographic outcomes than new-generation DES (NCT03610347).

Optical Coherence Tomography of the Coronary Arteries

Intravascular imaging, particularly optical coherence tomography, has brought significant improvement in diagnostic and therapeutical approaches to coronary artery disease and has offered superior high-resolution visualization of coronary arteries. The ability to obtain images of intramural and transmural coronary structures allows the study of the process of atherosclerosis, effect of therapies, mechanism of acute coronary syndrome and stent failure, and performance of new devices and enables the interventional cardiologist to optimize the effect of percutaneous coronary intervention. In this review, we provide the summary of the latest published data on clinical use of optical coherence tomography as well as practical algorithm for optical coherence tomography-guided percutaneous coronary intervention for daily interventional practice.

Differential Vascular Responses to New-Generation Drug-Eluting Stenting According to Clinical Presentation: Three-Month Optical Coherence Tomographic Study

We evaluated early vascular responses after new-generation drug-eluting stent (DES) implantation. From 2 randomized trials, we identified 471 patients (138 patients with acute myocardial infarction [AMI] vs 333 patients with stable angina or unstable angina [SA/UA]) treated by DESs who underwent serial optical coherence tomography (OCT) from postprocedure to 3 months. At 3-month follow-up OCT, malapposed strut percentage was higher in AMI than in SA/UA (5.3% vs 0.7%, P < .001); it was markedly increased from postprocedure in AMI (2.0%-5.3%, P < .001), whereas it decreased in SA/UA (1.7%-0.7%, P < .001). Patients with AMI showed a higher risk of persistent (59% vs 37%; P < .001) or late-acquired malapposition (15% vs 8%; P = .04). Uncovered strut percentage at 3 months was also higher in AMI than in SA/UA (13.1% vs 6.7%, P < .001). The AMI presentation was the significant risk factor for both significant stent malapposition (SM, ≥200 μm; odds ratio [OR] = 3.45, CI = 1.85-7.14, P < .001) and uncovered stent (% uncovered struts >6.0%; OR = 2.44, CI = 1.35-4.76, P = .004), together with malapposed distance and postprocedural thrombi. Further, AMI presentation was the predictor for the occurrence of early period late-acquired and persistent malapposition. Serial OCT comparison analyses showed that patients with AMI compared with patients with SA/UA showed more delayed strut coverage, more severe degree SM or uncovered stents, and higher incidences of early period persistent or late-acquired SM.

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.

The role of intracoronary imaging in translational research

Atherosclerotic cardiovascular disease is a key public health concern worldwide and leading cause of morbidity, mortality and health economic costs. Understanding atherosclerotic plaque microstructure in relation to molecular mechanisms that underpin its initiation and progression is needed to provide the best chance of combating this disease. Evolving vessel wall-based, endovascular coronary imaging modalities, including intravascular ultrasound (IVUS), optical coherence tomography (OCT) and near-infrared spectroscopy (NIRS), used in isolation or as hybrid modalities, have been advanced to allow comprehensive visualization of the pathological substrate of coronary atherosclerosis and accurately measure temporal changes in both the vessel wall and plaque characteristics. This has helped further our appreciation of the natural history of coronary artery disease (CAD) and the risk for major adverse cardiovascular events (MACE), evaluate the responsiveness to conventional and experimental therapeutic interventions, and assist in guiding percutaneous coronary intervention (PCI). Here we review the use of different imaging modalities for these purposes and the lessons they have provided thus far.

Supporting evidence from optical coherence tomography for shortening dual antiplatelet therapy after drug-eluting stents implantation

INTRODUCTION

Dual antiplatelet therapy (DAPT) is required for coronary artery disease treated with drug-eluting stents (DES) implantation. Shortening DAPT duration would be beneficial for patients with high bleeding risk.

AREAS COVERED

Early healing patterns, especially stent strut coverage, assessed by optical coherence tomography (OCT) as a surrogate of neointima have been investigated to make decisions on whether short DAPT would be a safe alternative. This review evaluates the OCT evidence (i.e. neointimal coverage of stent struts within 3 months) for shortening DAPT duration after DES implantation.

EXPERT COMMENTARY

Shortening DAPT (i.e. within 3 months) duration after DES implantation might reduce complications including bleeding without increasing stent thrombosis. However, the optimal duration of DAPT after DES implantation is under discussion. Long-term assessment of short DAPT is required for the decision of the new guidelines regarding the recommended duration of DAPT.

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.

Impact of late stent malapposition after drug-eluting stent implantation on long-term clinical outcomes

BACKGROUND AND AIMS

The impact of late drug-eluting stent (DES) malapposition detected by optical coherence tomography (OCT) on long-term clinical outcomes has not been clearly established. We evaluated long-term clinical outcomes of late stent malapposition (LSM) detected by OCT in a qualified study population.

METHODS

A total of 428 patients were selected from previous randomized OCT studies that evaluated the degree of strut coverage of different DESs at a 3-12-month follow-up OCT examination. These patients were assigned to one of two groups based on the presence (n = 136) or absence (n = 292) of LSM on follow-up OCT images (performed at 7.0 ± 3.4 months after DES implantation). The cumulative rates of composite events (cardiac death, target-vessel-related myocardial infarction, target-vessel revascularization, and stent thrombosis) were compared between the two groups.

RESULTS

During 73.7 ± 18.3 months of follow-up, cardiac death or (very) late stent thrombosis did not occur in either group. The cumulative rate of composite events was similar among the patients in each group (6.2% in patients with LSM vs. 11.7% in those without LSM) [hazard ratio (HR) = 0.569, 95% confidence interval (CI) = 0.257-1.257, p = 0.163]. Target vessel-related myocardial infarction occurred in 0.7% of patients with LSM vs. 1.5% of those without LSM (HR = 0.521, 95% CI = 0.058-4.670, p = 0.560). Target-vessel revascularization was performed in 5.4% of patients with LSM vs. 10.2% of those without LSM (HR = 0.574, 95% CI = 0.246-1.343, p = 0.201).

CONCLUSIONS

Cardiac death or (very) late stent thrombosis did not occur in patients with OCT-detected LSM during long-term follow-up. The presence of OCT-detected LSM was not associated with adverse clinical events.

The optimal duration of dual antiplatelet therapy after coronary stent implantation: to go too far is as bad as to fall short

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor is key for secondary prevention of recurrent coronary ischemic events and stent thrombosis. For this purpose, DAPT showed superior efficacy compared to aspirin alone, but it is also associated with an increased risk of major, and potentially fatal, bleeding. Hence, while secondary prevention with aspirin monotherapy is generally maintained for an indefinite period, the duration of DAPT after the index event is still debated. Multiple trials have challenged the guideline recommended standard of care of 12 months of DAPT duration. These studies tested on one side a treatment reduction to 6 or 3 months, and on the other side an extension of treatment beyond 12 months in order to define the optimal DAPT duration maximizing the anti-ischemic protection and minimizing bleeding. In this document we sought to summarize the existing evidence from more than 18 randomized controlled trials in the field, and discuss the benefit and risks of prolonging/shortening DAPT duration. In addition, a specific focus on treatment individualization will outline the current, evidence-based, decision-making process for optimal DAPT duration selection after coronary stenting.