Optical coherence tomography in coronary atherosclerosis assessment and intervention

Glycemic control and coronary plaque characteristics in patients with acute myocardial infarction

BACKGROUND

The impact of glycemic control on the morphological characteristics of non-culprit lesions (NCLs) in patients with acute myocardial infarction (AMI) remains unclear.

METHODS AND RESULTS

A total of 800 AMI patients who underwent 3-vessel OCT were divided into three groups based on their serum glycated hemoglobin (HbA1c) levels: poorly controlled diabetes mellitus (DM) (HbA1c ≥8.0 %, n = 79), well controlled DM (6.5 % ≤ HbA1c < 8.0 %, n = 105), and non-DM (HbA1c <6.5 %, n = 616). OCT imaging was performed on all NCLs and plaque characteristics were assessed at both the patient and lesion level, including high-risk features. Separate covariate-adjusted multivariate models were performed to determine whether glycemic control was associated with high-risk plaque features in NCLs. Patients with poorly controlled DM had higher NCL vulnerability compared to those with well controlled DM and non-DM, both at the patient level [thin-cap fibroatheroma (TCFA): 63.3 % vs. 32.4 % vs. 27.1 %] and the lesion level [TCFA: 22.1 % vs. 11.6 % vs. 9.5 %; non-culprit plaque rupture (PR): 8.4 % vs. 4.6 % vs. 4.6 %]. Vulnerable plaque features, including TCFA, non-culprit PR, macrophages, microchannels, cholesterol crystals, layered plaque and calcification, were more prevalent with increasing HbA1c levels. Multivariate analysis revealed that at the patient level, poorly controlled DM was an independent predictor of TCFA and microchannels, whereas at the lesion level it independently predicted TCFA and non-culprit PR.

CONCLUSIONS

In AMI patients, poor glycemic control is associated with increased vulnerability of NCLs. As HbA1c levels increase, there is a worsening of plaque characteristics, including greater plaque burden and more advanced features of vulnerability.

Discussion on the comparison of Raman spectroscopy and cardiovascular disease-related imaging techniques and the future applications of Raman technology: a systematic review

Cardiovascular disease (CVD) is a major cause of unnatural death worldwide, so timely diagnosis of CVD is crucial for improving patient outcomes. Although the traditional diagnostic tools can locate plaque and observe inner wall of blood vessel structure, they commonly have radioactivity and cannot detect the chemical composition of the plaque accurately. Recently emerging Raman techniques can detect the plaque composition precisely, and have the advantages of being fast, high-resolution and marker-free. This makes Raman have great potential for detecting blood samples, understanding disease conditions, and real-time monitoring. This review summarizes the origin and state-of-art of Raman techniques, including the following aspects: (a) the principle and technical classification of Raman techniques; (b) the applicability of Raman techniques and its comparison with traditional diagnostic tools at different diagnosis targets; (c) the applicability of Raman spectroscopy in advanced CVD. Lastly, we highlight the possible future applications of Raman techniques in CVD diagnosis.

Management of Coronary Stent Underexpansion

Coronary stent underexpansion is an important problem and limitation of percutaneous coronary intervention, adversely affecting both short- and long-term patient outcomes. Stent underexpansion occurs when a stent fails to expand adequately compared with the adjacent reference segment, resulting in inadequate luminal gain. Multiple studies suggest that stent underexpansion is associated with increased risks of in-stent restenosis, stent thrombosis, and myocardial infarction, resulting in recurrent symptoms, readmissions, repeat interventions, and increased mortality. Contributing factors for stent underexpansion include severe calcification, inadequate lesion preparation, suboptimal stent deployment, and preexisting in-stent restenosis. Calcific plaques, especially when present behind a previously implanted, underexpanded stent, pose a significant challenge for further stent optimization. These lesions are often resistant to high-pressure balloon dilatation and may require advanced techniques that carry increased risks of complications. Intravascular imaging modalities, such as intravascular ultrasound and optical coherence tomography, have emerged as essential tools in diagnosing and managing stent underexpansion. These techniques provide a more detailed evaluation of the vessel and previously implanted stent, enabling the clinician to understand the exact mechanism of stent failure, and assess plaque burden and morphology, which ultimately helps guide appropriate treatment strategies. Despite the clinical importance of stent underexpansion, there is currently no consensus on its optimal treatment, largely because of the absence of large prospective studies in this area. This comprehensive review aims to summarize the existing evidence, clinical experience, and treatment strategies for coronary stent underexpansion, with the goal of providing practical guidance to clinicians to help optimize percutaneous coronary intervention and patient outcomes.

Functional or anatomical assessment of non-culprit lesions in acute myocardial infarction

BACKGROUND

Previous studies have reported the value of quantitative flow ratio (QFR) to assess the physiological significance of non-culprit lesions (NCLs) in acute myocardial infarction (AMI) patients and of optical coherence tomography (OCT)-defined thin-cap fibroatheroma (TCFA) to identify non-culprit vulnerable plaques.

AIMS

We sought to systematically compare long-term NCL-related clinical prognosis in an AMI population utilising acute Murray fractal law-based QFR (μQFR) values and OCT-defined TCFA.

METHODS

Three-vessel OCT imaging and μQFR assessment were conducted in 645 AMI patients, identifying 1,320 intermediate NCLs in non-infarct-related arteries. The primary endpoint was a composite of cardiac death, NCL-related non-fatal myocardial infarction (MI), and NCL-related unplanned coronary revascularisation, with follow-up lasting up to 5 years.

RESULTS

The primary endpoint occurred in 59 patients (11.1%). OCT-defined TCFA independently predicted patient-level (adjusted hazard ratio [HR] 3.05, 95% confidence interval [CI]: 1.80-5.19) and NCL-specific primary endpoints (adjusted HR 4.46, 95% CI: 2.33-8.56). The highest event rate of 29.6% was observed in patients with NCLs that were TCFA (+) with μQFR ≤0.80, compared to 16.3% in those that were also TCFA (+) but with μQFR>0.80, 6.0% in those that were TCFA (-) with μQFR ≤0.80, and 6.6% in those that were TCFA (-) with μQFR>0.80 (log-rank p<0.001). TCFA was an independent predictor for the primary endpoint in ST-segment elevation MI (STEMI; adjusted HR 3.27, 95% CI: 1.67-6.41) and non-STEMI (adjusted HR 3.26, 95% CI: 1.24-8.54) patients, whereas μQFR ≤0.80 was not.

CONCLUSIONS

When assessing NCLs during the index procedure in AMI patients, OCT-defined TCFA serves as the dominant prognostic predictor for long-term clinical outcomes, rather than μQFR-determined physiological significance.

Mapping the distribution of radial artery atherosclerosis by optical coherence tomography

BACKGROUND

Radial artery plaque (RAP) can influence the function of arterial conduits after revascularization and hinder the maturation of arteriovenous fistulas in patients undergoing hemodialysis patients. However, the preferred in vivo sites for RAP development have not been systematically investigated. This study measured and evaluated RAP to map the distribution of RAP in the radial artery (RA) using optical coherence tomography (OCT).

METHODS

OCT images of the entire RA in 300 patients at 1 mm intervals were analyzed to assess RAP phenotypes and measure the distance of RAP from the radial artery ostium. The RA was evenly divided into three segments: proximal, middle, and distal. Patients were categorized into two groups: the RAP group (n = 68) and the non-RAP group (n = 232).

RESULTS

Among the 300 patients with 300 radial arteries studied, 68 patients (22.7%) developed 180 distinct RAPs. The distal segment was the most susceptible to RAP formation (51 patients; 17.0%).In plaque level analysis, Most RAPs (55%) were located ≥ 150 mm from the RA ostium. The distal segment exhibited a significantly higher median cumulative plaque index compared with the proximal and middle segments (p = 0.031). Logistic regression analysis identified aging, smoking, diabetes mellitus, and multi-vessel coronary disease (MVCD) as independent risk factors for RAP occurrence.

CONCLUSIONS

RAP was observed in 22.7% of patients with acute coronary syndrome (ACS), with a predominant localization in the distal segment, both at the patient and plaque level. Significant risk factors included aging, smoking, diabetes mellitus, and MVCD.

From Mechanisms to Management: Tackling In-Stent Restenosis in the Drug-Eluting Stent Era

PURPOSE OF REVIEW

Drug-eluting stent (DES) technology has greatly enhanced the safety and effectiveness of percutaneous coronary interventions (PCI). The aim of the present paper is to provide a comprehensive review of in-stent restenosis (ISR), focusing on the contemporary DES era, including its incidence, mechanisms, and imaging characterization.

RECENT FINDINGS

Despite the widespread use of DES and numerous improvements, recent clinical data indicate that ISR still occurs in 5-10% of PCI procedures, posing a considerable public health issue. The incidence, morphology, and clinical implications of ISR are determined by a complex interplay of several factors: the patient, stent, procedure, and vessel and lesion-related factors. Advancements in intracoronary imaging have provided greater insight into its patterns and underlying causes. Over time, treatment strategies have evolved, and current guidelines recommend an individualized approach using intracoronary imaging to characterize ISR's underlying substrate.

TEAD1-Mediated Trans-Differentiation of Vascular Smooth Muscle Cells into Fibroblast-Like Cells Contributes to the Stabilization and Repair of Disrupted Atherosclerotic Plaques

Atherosclerotic plaque rupture mainly contributes to acute coronary syndrome (ACS). Insufficient repair of these plaques leads to thrombosis and subsequent ACS. Central to this process is the modulation of vascular smooth muscle cells (VSMCs) phenotypes, emphasizing their pivotal role in atherosclerotic plaque stability and healing post-disruption. Here, an expansion of FSP1+ cells in a tandem stenosis (TS) model of atherosclerotic mice is unveiled, predominantly originating from VSMCs through single-cell RNA sequencing (scRNA-seq) analyses and VSMC lineage tracing studies. Further investigation identified TEA domain transcription factor 1 (TEAD1) as the key transcription factor driving the trans-differentiation of VSMCs into fibroblast-like cells. In vivo experiments using a TS model of plaque rupture demonstrated that TEAD1 played a crucial role in promoting plaque stability and healing post-rupture through pharmacological or TEAD1-AAV treatments. Mechanistically, it is found that TEAD1 promoted the expression of fibroblast markers through the Wnt4/β-Catenin pathway, facilitating the trans-differentiation. Thus, this study illustrated that TEAD1 played a critical role in promoting the trans-differentiation of VSMCs into fibroblast-like cells and subsequent extracellular matrix production through the Wnt4/β-Catenin pathway. Consequently, this process enhanced the healing mechanisms following plaque rupture, elucidating potential therapeutic avenues for managing atherosclerotic instability.

Development of a label-free, functional, molecular and structural imaging system combining optical coherence tomography and Raman spectroscopy for in vivo measurement of rat retina

In vivo access to molecular information of retinal tissue is considered to play a critical role in enabling early diagnosis of ophthalmic and neurodegenerative diseases. The current gold standard of retina imaging, optical coherence tomography and angiography provides only the retinal morphology and blood perfusion, missing the full spectrum of molecular information. Raman spectroscopy addresses this gap while keeping the investigation non-invasive and label-free. Although previous studies have demonstrated the huge diagnostic potential of combining both modalities for in vivo biological tissue measurement, some have either employed unsafe optical power levels for in vivo retinal measurements or presented results that were negative or contradictory. In this study, we have developed an eye-safe multimodal in vivo label-free imaging system and demonstrate the potential of this device by investigating the retina of a living albino rat. The acquired Raman spectra showed relevant Raman bands in comparison with the previous ex vivo studies. Using this multimodal imaging system for non-invasive retina measurements of transgenic rodents holds the potential to advance the understanding of the pathophysiology of both ophthalmic and neurodegenerative diseases.

Non-culprit plaque healing on serial OCT imaging and future outcome in patients with acute coronary syndromes

BACKGROUND AND AIMS

Histologic studies indicated that healed plaque, characterized by a multilayered pattern, is indicative of prior atherothrombosis and subsequent healing. However, longitudinal in vivo data on healed plaque formation in non-culprit plaques are limited. This study aimed to investigate serial changes and clinical significance of new layered pattern formation in non-culprit plaques in patients with acute coronary syndromes (ACS) using serial optical coherence tomography (OCT) imaging.

METHODS

ACS patients who underwent two OCTs at baseline and 1-year follow-up were included. Serial changes in morphologic characteristics of non-culprit plaques were evaluated. New layered pattern was defined as a new signal-rich layer on the plaque surface at follow-up that was not present at baseline.

RESULTS

Among 553 non-culprit plaques observed in 222 patients, 82 (14.8 %) exhibited a new layered pattern at follow-up. Thin-cap fibroatheroma, macrophage, and thrombus were identified as independent predictors of the new layered pattern. Plaques with new layered pattern formation showed a greater significant reduction in luminal area and lipid content, as well as a greater increase in fibrous cap thickness compared to those without. The incidence of 6-year non-culprit-related major adverse cardiac events was higher in patients with new layered pattern than in those without (25.4 % vs. 10.8 %, p = 0.011), mainly due to clinically driven coronary revascularization.

CONCLUSIONS

Plaque destabilization and subsequent healing frequently occur in non-culprit plaques after ACS. The formation of a new layered pattern may contribute to temporary plaque stabilization, but results in luminal stenosis and worse clinical outcomes.

FFR-Negative Nonculprit High-Risk Plaques and Clinical Outcomes in High-Risk Populations: An Individual Patient-Data Pooled Analysis From COMBINE (OCT-FFR) and PECTUS-obs

BACKGROUND

Despite fractional flow reserve (FFR)-guided deferral of revascularization, recurrent events in patients with diabetes or after myocardial infarction remain common. This study aimed to assess the association between FFR-negative but high-risk nonculprit lesions and clinical outcomes.

METHODS

This is a patient-level pooled analysis of the prospective natural-history COMBINE (OCT-FFR) study (Optical Coherence Tomography Morphologic and Fractional Flow Reserve Assessment in Diabetes Mellitus Patients) and PECTUS-obs study (Identification of Risk Factors for Acute Coronary Events by OCT After STEMI and NSTEMI Patients With Residual Non- Flow Limiting Lesions). Optical coherence tomography was performed on all FFR-negative (FFR >0.80) native nonculprit lesions. Patients or lesions with a high-risk plaque were compared with those without a high-risk plaque. A high-risk plaque was defined in the presence of at least 2 prespecified criteria: (1) lipid arc ≥90o, (2) minimum fibrous cap thickness <65 µm, and (3) presence of either plaque rupture or thrombus. The primary end points were native major adverse cardiovascular events (composite of all-cause mortality, nonfatal myocardial infarction, or unplanned revascularization excluding stent-failure-related events and nonattributable events) and target lesion failure (composite of cardiac death, target vessel myocardial infarction, or target lesion revascularization).

RESULTS

Among 810 patients, 450 (55.6%) had a history of diabetes and 482 (59.5%) presented with myocardial infarction. At least 1 high-risk plaque was identified in 271 (33.5%) patients and 287 (30.6%) lesions. Over a median follow-up of 761 (interquartile range, 731-1175) days, the presence of a high-risk plaque was associated with patient-level native major adverse cardiovascular events (hazard ratio, 2.127 [95% CI, 1.451-3.120]; P<0.001) and lesion-level target lesion failure (hazard ratio, 2.623 [95% CI, 1.559-4.414]; P<0.001). The risk of adverse outcomes increased with the copresence of multiple high-risk features.

CONCLUSIONS

FFR-negative but high-risk nonculprit lesions are associated with adverse patient- and lesion-level clinical outcomes. These findings emphasize the additional value of intracoronary imaging in patients with FFR-negative nonculprit lesions.

REGISTRATION

URL: https://clinicaltrials.gov; Unique identifier: NCT02989740; Unique identifier: NCT03857971.

Effect of Intensive Lipid-Lowering Therapy on Coronary Plaque Stabilization Derived from Optical Coherence Tomography: a Meta-analysis and Meta-regression

PURPOSE

The definitive impacts of intensive lipid-lowering therapy (LLT) on plaque stabilization and the relationship between the key markers during LLT and plaque stability remain unquestioned. Thus, these meta-analysis and meta-regression intend to holistically evaluate the influence exerted by rigorous LLT on the minimum fibrous cap thickness (FCT) and maximum lipid arc as discerned through optical coherence tomography (OCT). This study further scrutinizes the correlation of this impact with variations in high-sensitivity C-reactive protein (hs-CRP), low-density lipoprotein cholesterol (LDL-C), or additional parameters within patients diagnosed with coronary artery disease (CAD).

METHODS

Comprehensive searches were conducted on platforms including PubMed, Embase, and the Cochrane Library for randomized controlled trials (RCTs) published until June 1, 2023. The search was language agnostic and targeted RCTs elaborating on the correlation between high-intensity statin therapy or statins used concomitantly with other lipid-lowering medications and the minimum FCT and maximum lipid arc as assessed by OCT. The meta-analyses were executed employing a standard mean difference (SMD) algorithm with random-effects on continuous variables. These methodologies align with the Preferred Reporting Items for Systematic and Meta-analysis (PRISMA) guidelines.

RESULTS

A spectrum of 12 RCTs engaging 972 patients were identified and mobilized for these analyses. Meta-analysis outcomes depicted a conspicuous correlation between intensive LLT and an enhanced minimum FCT (12 studies with 972 participants; SMD, 0.87; 95% CI, 0.54 to 1.21; P < 0.01), reduced maximum lipid arc (9 studies with 564 participants; SMD, -0.43; 95% CI, -0.58 to -0.29; P < 0.01). Meta-regression analysis has determined an association of elevated minimum FCT with decreased LDL-C (β, -0.0157; 95% CI, -0.0292 to -0.0023; P = 0.025), total cholesterol (TC) (β, -0.0154; 95% CI, -0.0303 to -0.0005; P = 0.044), and apolipoprotein B (ApoB) (β, -0.0209; 95% CI, -0.0361 to -0.0057; P = 0.022). However, no significant association was discerned relative to variations in hs-CRP/CRP (β, -0.1518; 95% CI, -1.3766 to -1.0730; P = 0.772), triglyceride (TG) (β, -0.0030; 95% CI, -0.0258 to -0.0318; P = 0.822), and high-density lipoprotein cholesterol (HDL-C) (β, 0.0313; 95% CI, -0.0965 to 0.1590; P = 0.608). Subsequent subgroup meta-analysis demonstrated that high-intensity statin therapy (5 studies with 204 participants; SMD, 1.03; 95% CI, 0.67 to 1.39; P < 0.01), as well as a combinative approach including PCSK9 antibodies and statins (3 studies with 522 participants; SMD, 1.17; 95% CI, 0.62 to 1.73; P < 0.01) contributed to an increase in minimum FCT. Parallelly, high-intensity statin therapy (4 studies with 183 participants; SMD, -0.42; 95% CI, -0.65 to -0.19; P < 0.01) or the combined application of PCSK9 antibodies and statins (2 studies with 222 participants; SMD, -0.98; 95% CI, -1.26 to -0.70; P < 0.01) was evidenced to decrease the maximum lipid arc.

CONCLUSIONS

Intensive LLT, mainly high-intensity statin therapy and combined PCSK9 antibody with statin, has a beneficial effect on coronary plaque stabilization derived from OCT in patients with CAD. Coronary plaque stabilization is primarily due to lipid-lowering effect, not anti-inflammatory effect. Moreover, the lipid-lowering effect has nothing to do with the changes in HDL-C and TG, but is mainly related to the reduction of LDL-C, TC, and ApoB.

High-risk plaques in non-culprit lesions and clinical outcome after NSTEMI vs. STEMI

AIMS

Complete non-culprit (NC) revascularisation may help reduce recurrent events after non-ST-segment elevation myocardial infarction (NSTEMI), especially if NC lesions would harbour high-risk plaque (HRP) features similar to ST-segment elevation myocardial infarction (STEMI). This study aimed to assess differences in fractional flow reserve (FFR)-negative NC plaque morphology in patients presenting with NSTEMI vs. STEMI and assess the association of HRP morphology and clinical outcome.

METHODS AND RESULTS

In the prospective PECTUS-obs study, 438 patients presenting with myocardial infarction (MI) underwent optical coherence tomography (OCT) of all FFR-negative intermediate NC lesions. The primary endpoint was the occurrence of major adverse cardiovascular events (MACE, composite of all-cause mortality, non-fatal MI or unplanned revascularisation) at 2-year follow-up. Four hundred and twenty patients had at least one analysable OCT, including 203 (48.3%) with NSTEMI and 217 (51.7%) with STEMI. The prevalence of HRPs, including thin-cap fibroatheromas, plaque rupture, and thrombus, was comparable between groups. MACE occurred in 29 (14.3%) NSTEMI patients and 16 (7.4%) STEMI patients (Puni-variable = 0.025 and Pmulti-variable = 0.270). Incidence of MACE was numerically higher among patients with HRP, irrespective of the clinical presentation at index (Pinteraction = 0.684). Among HRP criteria, plaque rupture was associated with MACE in both NSTEMI (P < 0.001) and STEMI (P = 0.020).

CONCLUSION

Presence of NC HRP is comparable between NSTEMI and STEMI and leads to numerically higher event rates in both. These results call for additional research on complete revascularisation in NSTEMI and treatment of HRP.

CLINICAL TRIAL REGISTRATION

NCT03857971.

Prevalence of intracerebral thrombus detected by optical coherence tomography in patients with posterior circulation stroke or transient ischemic attack

BACKGROUND

The incidence of thrombosis in patients with intracranial atherosclerotic stenosis (ICAS) remains unclear. Optical coherence tomography (OCT) has the potential to explore the vessel wall structure of posterior-circulation ICAS because of its relatively straight anatomical structure compared with that of the anterior cerebral arteries. This study aimed to determine the prevalence and characteristics of thrombosis in the posterior-circulation ICAS using OCT.

METHODS

This prospective study was conducted on 135 patients with posterior-circulation arterial stenosis who underwent OCT. All patients were symptomatic and had a severely stenotic lesion (70-99%) in the vetebrobasilar artery. The enrolled patients were classified according to the presence of in situ thrombus as defined by OCT. Clinical data and OCT characteristics were compared.

RESULTS

Eighty-two patients diagnosed with posterior-circulation ICAS were enrolled. In situ thrombi were identified in 34 patients. Clinically, patients with in situ thrombus were more prone to cerebral infarctions than transient ischemic attacks. The percentage area of stenosis in the non-thrombus group was significantly lower than that in the thrombus group. The thrombus burden, mean flow area, mean thrombus area, maximum lipid arc, and mean lumen area were significantly different among white, red, and mixed thrombi.

CONCLUSIONS

We achieved in vivo vessel wall structural analysis of posterior-circulation ICAS with the largest sample size. We also revealed the true incidence of in situ thrombosis and potential corresponding clinical events of posterior-circulation ICAS for the first time.

Macrophage-based pathogenesis and theranostics of vulnerable plaques

Vulnerable plaques, which are high-risk features of atherosclerosis, constitute critical elements in the disease's progression due to their formation and rupture. Macrophages and macrophage-derived foam cells are pivotal in inducing vulnerability within atherosclerotic plaques. Thus, understanding macrophage contributions to vulnerable plaques is essential for advancing the comprehension of atherosclerosis and devising novel therapeutic and diagnostic strategies. This review provides an overview of the pathological characteristics of vulnerable plaques, emphasizes macrophages' critical role, and discusses advanced strategies for their diagnosis and treatment. It aims to present a comprehensive macrophage-centered perspective for addressing vulnerable plaques in atherosclerosis.

Predictive models for cholesterol crystals and plaque vulnerability in acute myocardial infarction: Insights from an optical coherence tomography study

BACKGROUND

Cholesterol crystals (CCs) are recognized as a risk factor for vulnerable atherosclerotic plaque rupture (PR) and major adverse cardiovascular events. However, their predictive factors and association with plaque vulnerability in patients with acute myocardial infarction (AMI) remain insufficiently explored. Therefore, This study aims to investigate the association between CCs and plaque vulnerability in culprit lesions of AMI patients, identify the factors influencing CCs formation, and develop a predictive model for CCs.

METHODS

A total of 431 culprit lesions from AMI patients who underwent pre-intervention optical coherence tomography (OCT) imaging were analyzed. Patients were divided into groups based on the presence or absence of CCs and PR. The relationship between CCs and plaque vulnerability was evaluated. A risk nomogram for predicting CCs was developed using the least absolute shrinkage and selection operator and logistic regression analysis.

RESULTS

CCs were identified in 64.5 % of patients with AMI. The presence of CCs was associated with a higher prevalence of vulnerable plaque features, such as thin-cap fibroatheroma (TCFA), PR, macrophage infiltration, neovascularization, calcification, and thrombus, compared to patients without CCs. The CCs model demonstrated an area under the curve (AUC) of 0.676 for predicting PR. Incorporating CCs into the TCFA model (AUC = 0.656) significantly enhanced predictive accuracy, with a net reclassification improvement index of 0.462 (95 % confidence interval [CI]: 0.263-0.661, p < 0.001) and an integrated discrimination improvement index of 0.031 (95 % CI: 0.013-0.048, p = 0.001). Multivariate regression analysis identified the atherogenic index of plasma (odds ratio [OR] = 2.417), TCFA (OR = 1.759), macrophage infiltration (OR = 3.863), neovascularization (OR = 2.697), calcification (OR = 1.860), and thrombus (OR = 2.430) as independent risk factors for CCs formation. The comprehensive model incorporating these factors exhibited reasonable discriminatory ability, with an AUC of 0.766 (95 % CI: 0.717-0.815) in the training set and 0.753 (95 % CI: 0.704-0.802) in the internal validation set, reflecting good calibration. Decision curve analysis suggested that the model has potential clinical utility within a threshold probability range of approximately 18 % to 85 %.

CONCLUSIONS

CCs were associated with plaque vulnerability in the culprit lesions of AMI patients. Additionally, this study identified key factors influencing CCs formation and developed a predictive model with potential clinical applicability.

Timing of multivessel revascularization in stable patients with STEMI: a systematic review and network meta-analysis

INTRODUCTION AND OBJECTIVES

Multivessel percutaneous coronary intervention (MV-PCI) is recommended in patients with ST-segment elevation myocardial infarction (STEMI) and multivessel coronary artery disease (CAD) without cardiogenic shock. The present network meta-analysis investigated the optimal timing of MV-PCI in this context.

METHODS

We pooled the aggregated data from randomized trials investigating stable STEMI patients with multivessel CAD treated with a strategy of either MV-PCI or culprit vessel-only PCI. The primary outcome was all-cause death. The main secondary outcomes were cardiovascular death, myocardial infarction, and unplanned ischemia-driven revascularization.

RESULTS

Among 11 trials, a total of 10 507 patients were randomly assigned to MV-PCI (same sitting, n=1683; staged during the index hospitalization, n=3460; staged during a subsequent hospitalization within 45 days, n=3275) or to culprit vessel-only PCI (n=2089). The median follow-up was 18.6 months. In comparison with culprit vessel-only PCI, MV-PCI staged during the index hospitalization significantly reduced all-cause death (risk ratio, 0.73; 95%CI, 0.56-0.92; P=.008) and ranked as possibly the best treatment option for this outcome compared with all other strategies. In comparison with culprit vessel-only PCI, a MV-PCI reduced cardiovascular mortality without differences dependent on the timing of revascularization. MV-PCI within the index hospitalization, either in a single procedure or staged, significantly reduced myocardial infarction and unplanned ischemia-driven revascularization, with no significant difference between each other.

CONCLUSIONS

In patients with STEMI and multivessel CAD without cardiogenic shock, multivessel PCI within the index hospitalization, either in a single procedure or staged, represents the safest and most efficacious approach. The different timings of multivessel PCI did not result in any significant differences in all-cause death. This study is registered at PROSPERO (CRD42023457794).

Relationship Between Coronary Artery Calcium Score and Vulnerability of Culprit Plaque Assessed by OCT in Patients With Established Coronary Artery Disease

BACKGROUND

Coronary artery calcium score (CACS) is widely used for risk stratification. However, in patients with established coronary artery disease, its clinical implication and relationship with plaque vulnerability are unclear. We sought to correlate the CACS and plaque vulnerability assessed by optical coherence tomography.

METHODS

Patients with coronary artery disease who had CACS and optical coherence tomography before percutaneous coronary intervention were included. Patients were divided into 5 groups based on CACS: CACS of 0, 1 to 99, 100 to 399, 400 to 999, and ≥1000. Optical coherence tomography-derived vulnerable features in culprit plaque were compared between the groups.

RESULTS

In 460 patients, the prevalence of lipid-rich plaque, macrophage, and cholesterol crystal significantly differed among the 5 groups, being lowest in the patients with a CACS of 0. The prevalence of thin-cap fibroatheroma tended to be lower in those with a CACS of 0. No significant difference in vulnerable features was observed between the 4 groups with CACS >0. In the 2-group comparison between the group with a CACS of 0 and the other 4 groups combined, the prevalence of lipid-rich plaque (60.5% versus 85.9%; P<0.001), macrophage (48.8% versus 74.1%; P<0.001), thin-cap fibroatheroma (16.3% versus 35.0%; P=0.013), and cholesterol crystal (11.6% versus 32.9%; P=0.004) was significantly lower in the patients with CACS of 0. CACS of 0 was independently negatively associated with lipid-rich plaque, macrophage, thin-cap fibroatheroma, and cholesterol crystal after adjustment for patient characteristics.

CONCLUSIONS

Patients with a CACS of 0 have a significantly lower prevalence of vulnerable plaque features compared with those with CACS >0 in patients with established coronary artery disease.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04523194.

Ten-year clinical outcomes after drug-eluting stents implantation according to clinical presentation-Insights from the DECADE cooperation

BACKGROUND

Investigations of very long-term outcomes after percutaneous coronary intervention (PCI) with drug-eluting stents (DES) according to clinical presentation are scarce. Here, we investigated the 10-year clinical outcomes of patients undergoing DES-PCI according to clinical presentation.

METHODS

Patient-level data from five randomized trials with 10-year follow-up after DES-PCI were pooled. Patients were dichotomized into acute coronary syndrome (ACS) or chronic coronary syndrome (CCS) groups as per clinical presentation. The primary outcome was all-cause death. Secondary outcomes were cardiovascular death, myocardial infarction (MI), definite stent thrombosis (ST) and repeat revascularization involving the target lesion (TLR), target vessel (TVR) or non-target vessel (nTVR).

RESULTS

Of the 9700 patients included in this analysis, 4557 presented with ACS and 5143 with CCS. Compared with CCS patients, ACS patients had a higher risk of all-cause death and nTVR in the first year, but comparable risk thereafter. In addition, ACS patients had a higher risk of MI [adjusted hazard ratio 1.21, 95% confidence interval (1.04-1.41)] and definite ST [adjusted hazard ratio 1.48, 95% confidence interval (1.14-1.92)], while the risk of TLR and TVR was not significantly different up to 10-year follow-up.

CONCLUSIONS

Compared to CCS patients, ACS patients treated with PCI and DES implantation have an increased risk of all-cause death and repeat revascularization of remote vessels up to 1 year, with no significant differences thereafter and up to 10-year follow-up. ACS patients have a consistently higher risk of MI and definite ST. Whether these differences persist with current antithrombotic and secondary prevention therapies requires further investigation.

Role of optical coherence tomography in clinical management of myocardial infarction with nonobstructive coronary arteries

Myocardial infarction without angiographic moderate to severe stenosis (> 50%) and any other related diagnosis on clinical presentation is defined as myocardial infarction with nonobstructive coronary arteries (MINOCA). Common causes of MINOCA working diagnosis includes plaque disruption, spontaneous coronary artery dissection, coronary artery spasm, coronary thromboembolism, Takotsubo cardiomyopathy, and myocarditis. Clinical history, assay of myocardial enzymes, electrocardiogram, echocardiography, coronary angiography, and left ventriculography facilitate the initial diagnosis of MINOCA and reveal the underlying causes, while cardiovascular magnetic resonance and optical coherence tomography (OCT) are used to confirm the diagnosis. Although cardiovascular magnetic resonance is the gold standard noninvasive diagnostic tool for MINOCA, its ability to diagnose the cause and mechanism underlying this condition in the coronary arteries is limited because of its image resolution. Observational studies have demonstrated that OCT can be used to determine the underlying cause of MINOCA by investigating the characteristics of the culprit lesions and to predict the prognosis of the patients. In this article, we review the current diagnostic approach for MINOCA focusing on each imaging tool. Furthermore, we reevaluate the role of OCT in the clinical management of MINOCA. Identifying the cause of MINOCA through OCT might help select optimal and effective drug treatments and improve prognosis.

Synthetic polarization-sensitive optical coherence tomography using contrastive unpaired translation

Polarization-sensitive optical coherence tomography (PS-OCT) measures the polarization state of backscattered light from tissues and provides valuable insights into the birefringence properties of biological tissues. Contrastive unpaired translation (CUT) was used in this study to generate a synthetic PS-OCT image from a single OCT image. The challenges related to extensive data requirements relying on labeled datasets using only pixel-wise correlations that make it difficult to efficiently regenerate the periodic patterns observed in PS-OCT images were addressed. The CUT model captures birefringence patterns by leveraging patch-wise correlations from unpaired data, which allows learning of the underlying structural features of biological tissues responsible for birefringence. To demonstrate the performance of the proposed approach, three generative models (Pix2pix, CycleGAN, and CUT) were compared on an in vivo dataset of injured mouse tendons over a six-week healing period. CUT outperformed Pix2pix and CycleGAN by producing high-fidelity synthetic PS-OCT images that closely matched the original PS-OCT images. Pearson correlation and two-way ANOVA tests confirmed the superior performance of CUT (p-value < 0.0001) over the comparison models. Additionally, a ResNet-152 classification model was used to assess tissue damage, which achieved an accuracy of up to 90.13% compared to the original PS-OCT images. This research demonstrates that CUT is superior to conventional methods for generating high-quality synthetic PS-OCT images and offers better improvements in most scenarios, in terms of efficiency and image fidelity.

The relationship between atherogenic index of plasma and plaque vulnerabilities: an optical coherence tomography study

BACKGROUND

Atherogenic index of plasma (AIP) has been recommended as a marker of plasma atherogenicity. The impact of AIP on plaque characteristics is not fully understood.

PURPOSE

The study investigates the relationship between AIP and coronary plaque features in patients with acute coronary syndrome (ACS).

METHODS

From January 2016 to June 2017 pre-intervention optical coherence tomography (OCT) was performed in 522 ACS patients. AIP was defined as the base 10 logarithm of the ratio of the concentrations of triglyceride to high-density lipoprotein cholesterol. Patients were divided into four groups according to AIP quartiles.

RESULTS

A total of 332 patients were included for the analysis. The prevalence of thin-cap fibroatheroma (TCFA) (group I [lowest] 9.09% vs group II 16.5% vs group III 44.7% vs group IV [highest] 52.9%), macrophage accumulation (group I 18.2% vs group II 22.4% vs group III 31.8% vs group IV 47.1%), plaque rupture (group I 10.4% vs group II 14.1% vs group III 17.6% vs group IV 34.1%) and plaque erosion (group I 2.6% vs group II 2.4% vs group III 14.1% vs group IV 12.9%) were significantly different among AIP quartiles. Multivariate logistic regression revealed the risk of TCFA (odds ratio 11.130, 95% confidence interval 4.186-29.593, p < 0.001) and plaque rupture (OR 5.332, 95% CI 2.040-13.937, p < 0.001) increased in group IV compared to group I. Receiver operating characteristics curve showed the predictive value of AIP for TCFA and plaque rupture were 0.720 and 0.669 respectively.

CONCLUSION(S)

AIP is an independent predictor for vulnerable plaques beyond traditional factors. It can be integrated in clinical practice for risk stratification of ACS patients.

TRIAL REGISTRATION

All patients gave their consent to participate in the study and the Ethics Committee of Beijing Anzhen Hospital, Capital Medical University approved it (2020047X).

Photothermal optical coherence microscopy for studying lipid architecture in human carotid arteries

Photothermal optical coherence microscopy (PT-OCM) combines the high-resolution, label-free morphological imaging of OCM with the ability to discriminate tissue composition through phase-sensitive photothermal imaging. In this study, we perform 2D imaging of human carotid endarterectomies to spectrally determine lipid distribution, with verification via histologically stained samples. The structural information from OCM is combined with the spectral information gained from measuring the resulting sample surface displacement from thermoelastic expansion, following light irradiation. PT-OCM is thus demonstrated as a potential tool in the investigation of atherosclerotic plaque lipids, contributing towards the understanding of plaque instability.

Extracellular RIPK3 Acts as a Damage-Associated Molecular Pattern to Exaggerate Cardiac Ischemia/Reperfusion Injury

BACKGROUND

Cardiac ischemia/reperfusion (I/R) injury has emerged as an important therapeutic target for ischemic heart disease. Currently, there is no effective therapy for reducing cardiac I/R injury. Damage-associated molecular patterns are endogenous molecules released after cellular damage to exaggerate tissue inflammation and injury. RIPK3 (receptor-interacting protein kinase 3), a well-established intracellular mediator of cell necroptosis and inflammation, serves as a circulating biomarker of multiple diseases. However, whether extracellular RIPK3 also exerts biological functions in cardiac I/R injury remains totally unknown.

METHODS

Patients with acute myocardial infarction receiving percutaneous coronary intervention (PCI) were recruited independently in the discovery cohort (103 patients) and validation cohort (334 patients), and major adverse cardiovascular events were recorded. Plasma samples were collected before and after PCI (6 and 24 h) for RIPK3 concentration measurement. Cultured neonatal rat ventricular myocytes, macrophages and endothelial cells, and in vivo mouse models with myocardial injury induced by I/R (or hypoxia/reoxygenation) were used to investigate the role and mechanisms of extracellular RIPK3. Another cohort including patients with acute myocardial infarction receiving PCI and healthy volunteers was recruited to further explore the mechanisms of extracellular RIPK3.

RESULTS

In the discovery cohort, elevated plasma RIPK3 levels after PCI are associated with poorer short- and long-term outcomes in patients with acute myocardial infarction, as confirmed in the validation cohort. In both cultured cells and in vivo mouse models, recombinant RIPK3 protein exaggerated myocardial I/R (or hypoxia/reoxygenation) injury, which was alleviated by the RIPK3 antibody. Mechanistically, RIPK3 acted as a damage-associated molecular pattern and bound with RAGE (receptor of advanced glycation end-products), subsequently activating CaMKII (Ca2+/calmodulin-dependent kinase II) to elicit the detrimental effects. The positive correlation between plasma RIPK3 concentrations and CaMKII phosphorylation in human peripheral blood mononuclear cells was confirmed.

CONCLUSIONS

We identified the positive relationship between plasma RIPK3 concentrations and the risk of major adverse cardiovascular events in patients with acute myocardial infarction receiving PCI. As a damage-associated molecular pattern, extracellular RIPK3 plays a causal role in multiple pathological conditions during cardiac I/R injury through RAGE/CaMKII signaling. These findings expand our understanding of the physiological and pathological roles of RIPK3, and also provide a promising therapeutic target for myocardial I/R injury and the associated complications.

Unlocking the Secrets of Acute Coronary Syndromes Using Intravascular Imaging: From Pathophysiology to Improving Outcomes

Acute coronary syndrome (ACS) represents the most severe manifestation of coronary artery disease. Intravascular imaging, both intravascular ultrasound (IVUS) and optical coherence tomography (OCT), have played crucial roles for the impressive reduction in mortality of ACS. Intravascular imaging is useful for the detection of atherosclerotic mechanism (plaque rupture, calcified nodules, or plaque erosions) and for the evaluation of nonatherosclerotic and nonobstructive types of ACS. In addition, IVUS and OCT play a crucial role in the optimization of the PCI. The aim of the current review is to present the role of intravascular imaging in identifying the mechanisms of ACS and its prognostic role in future events, to review the current guidelines suggesting intravascular imaging use in ACS, to summarize its role in PCI in patients with ACS, and to compare IVUS and OCT.

Management of vulnerable patient phenotypes and acute coronary syndrome mechanisms

Atherosclerosis is a chronic vascular disease. Its prevalence increases with aging. However, atherosclerosis may also affect young subjects without significant exposure to the classical risk factors. Recent evidence indicates clonal hematopoiesis of indeterminate potential (CHIP) as a novel cardiovascular risk factor that should be suspected in young patients. CHIP represents a link between impaired bone marrow and atherosclerosis. Atherosclerosis may present with an acute symptomatic manifestation or subclinical events that favor plaque growth. The outcome of a plaque relies on a balance of innate and environmental factors. These factors can influence the processes that initiate and propagate acute plaque destabilization leading to intraluminal thrombus formation or subclinical vessel healing. Thirty years ago, the first autopsy study revealed that coronary plaques can undergo rupture even in subjects without a known cardiovascular history. Nowadays, cardiac magnetic resonance studies demonstrate that this phenomenon is not rare. Myocardial infarction is mainly due to plaque rupture and plaque erosion that have different pathophysiological mechanisms. Plaque erosion carries a better prognosis as compared to plaque rupture. Thus, a tailored conservative treatment has been proposed and some studies demonstrated it to be safe. On the contrary, plaque rupture is typically associated with inflammation and anti-inflammatory treatments have been proposed in response to persistently elevate biomarkers of systemic inflammation. In conclusion, atherosclerosis may present in different forms or phenotypes. Vulnerable patient phenotypes, identified by using intravascular imaging techniques, biomarkers, or even genetic analyses, are characterized by distinctive pathophysiological mechanisms. These different phenotypes merit tailored management.

Diagnostic and therapeutic optical imaging in cardiovascular diseases

Cardiovascular disease (CVD) is one of the most prevalent health threats globally. Traditional diagnostic methods for CVDs, including electrocardiography, ultrasound, and cardiac magnetic resonance imaging, have inherent limitations in real-time monitoring and high-resolution visualization of cardiovascular pathophysiology. In recent years, optical imaging technology has gained considerable attention as a non-invasive, high-resolution, real-time monitoring solution in the study and diagnosis of CVD. This review discusses the latest advancements, and applications of optical techniques in cardiac imaging. We compare the advantages of optical imaging over traditional modalities and especially scrutinize techniques such as optical coherence tomography, photoacoustic imaging, and fluorescence imaging. We summarize their investigations in atherosclerosis, myocardial infarction, and heart valve disease, etc. Additionally, we discuss challenges like deep-tissue imaging and high spatiotemporal resolution adjustment, and review existing solutions such as multimodal integration, artificial intelligence, and enhanced optical probes. This article aims to drive further development in optical imaging technologies to provide more precise and efficient tools for early diagnosis, pathological mechanism exploration, and treatment of CVD.

Optical coherence tomography predictors of clinical outcomes after stent implantation: the ILUMIEN IV trial

BACKGROUND AND AIMS

Observational registries have suggested that optical coherence tomography (OCT) imaging-derived parameters may predict adverse events after drug-eluting stent (DES) implantation. The present analysis sought to determine the OCT predictors of clinical outcomes from the large-scale ILUMIEN IV trial.

METHODS

ILUMIEN IV was a prospective, single-blind trial of 2487 patients with diabetes or high-risk lesions randomized to OCT-guided versus angiography-guided DES implantation. All patients underwent final OCT imaging (blinded in the angiography-guided arm). From more than 20 candidates, the independent OCT predictors of 2-year target lesion failure (TLF; the primary endpoint), cardiac death or target-vessel myocardial infarction (TV-MI), ischaemia-driven target lesion revascularization (ID-TLR), and stent thrombosis were analysed by multivariable Cox proportional hazard regression in single treated lesions.

RESULTS

A total of 2128 patients had a single treated lesion with core laboratory-analysed final OCT. The 2-year Kaplan-Meier rates of TLF, cardiac death or TV-MI, ID-TLR, and stent thrombosis were 6.3% (n = 130), 3.3% (n = 68), 4.3% (n = 87), and 0.9% (n = 18), respectively. The independent predictors of 2-year TLF were a smaller minimal stent area (per 1 mm2 increase: hazard ratio 0.76, 95% confidence interval 0.68-0.89, P < .0001) and proximal edge dissection (hazard ratio 1.77, 95% confidence interval 1.20-2.62, P = .004). The independent predictors of cardiac death or TV-MI were smaller minimal stent area and longer stent length; of ID-TLR were smaller intra-stent flow area and proximal edge dissection; and of stent thrombosis was smaller minimal stent expansion.

CONCLUSIONS

In the ILUMIEN IV trial, the most important OCT-derived post-DES predictors of both safety and effectiveness outcomes were parameters related to stent area, expansion and flow, proximal edge dissection, and stent length.

The clinical relevance of the reversal of coronary atherosclerotic plaque

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of death globally despite advances in preventive therapies. Understanding of the initiation and progression of atherosclerosis, the interplay between lipoproteins, endothelial dysfunction, inflammation, and immune responses is critical to treating this disease. The development of vulnerable coronary plaques prone to thrombosis, can lead to acute coronary syndromes, for these reasons, the potential plaque stabilization and regression through pharmacological interventions, particularly lipid-lowering agents like statins and PCSK9 inhibitors is crucial. The imaging techniques such as intravascular ultrasound (IVUS), near-infrared spectroscopy (NIRS), and optical coherence tomography (OCT) play a key role in assessing plaque composition and guiding interventional therapeutic strategies. Clinical evidence supports the efficacy of intensive lipid-lowering therapy in inducing plaque regression, with studies demonstrating reductions in plaque volume and improvements in plaque morphology assessed by IVUS, OCT and NIRS. While pharmacological interventions show promise in promoting plaque regression and stabilization, their impact on long-term cardiovascular events requires further investigation. Multimodality imaging and comprehensive outcome trials are proposed as essential tools for elucidating the relationship between plaque modification and clinical benefit in coronary atherosclerosis. The stabilization or regression of atherosclerotic plaque might serve as the phenomenon linking the reduction in LDL-C levels to the decrease in cardiovascular events. Overall, this review emphasizes the ongoing efforts to advance our understanding of ASCVD pathophysiology and optimize therapeutic approaches for improving patient outcomes.

Differences in total plaque burden between plaque rupture and plaque erosion: A combined computed tomography angiography and optical coherence tomography study

BACKGROUNDS

Coronary computed tomography angiography (CTA) allows for the assessment of atherosclerotic plaque burden across the entire coronary vasculature. No studies have examined the relationship between the underlying pathology of the culprit lesion and total plaque burden in patients with acute coronary syndromes. The aim of this study was to compare the total plaque burden between patients with plaque rupture versus plaque erosion.

METHODS

A total of 232 patients who presented with their first non-ST-segment elevation acute coronary syndrome and underwent both CTA and optical coherence tomography imaging before intervention were selected. Quantitative analysis was performed using semi-automated software (Autoplaque version 3.0, Cedars-Sinai Medical Center). An attenuation of <30 Hounsfield units defined low-density non-calcified plaque (LDNCP). All 3 vessels were assessed using the modified 17-segment American Heart Association model for coronary segment classification.

RESULTS

Among 232 patients, 125 (53.9%) had plaque rupture and 107 (46.1%) had plaque erosion. Total plaque burden (48.2 [39.8-54.9] % vs. 44.1 [38.6-50.0] %, P ​= ​0.006), total non-calcified plaque (NCP) burden (46.6 [39.1-53.3] % vs. 43.0 [37.6-49.2] %, P ​= ​0.013), total LDNCP burden (2.3 [1.4-3.0] % vs. 1.7 [1.2-2.6] %, P ​= ​0.016), and total calcified plaque (CP) burden (0.8 [0.1-1.6] % vs. 0.4 [0.0-1.4] %, P ​= ​0.047) were significantly greater in patients with culprit plaque rupture than in those with culprit plaque erosion.

CONCLUSION

Patients with plaque rupture, compared with those with plaque erosion, had a greater total plaque burden, NCP burden, LDNCP burden, and CP burden.

CLINICAL TRIAL REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04523194.

Relationship between plaque burden and plaque vulnerability: Acute coronary syndromes versus chronic coronary syndrome

BACKGROUND

The relationship between plaque burden and microscopic characterization of plaque features as it pertains to clinical presentation has not been fully investigated. The aim of this study was to compare the relationship between plaque burden and plaque vulnerability in patients with acute coronary syndromes (ACS) versus chronic coronary syndrome (CCS).

METHODS

Patients who underwent both coronary computed tomography angiography (CTA) and optical coherence tomography (OCT) before coronary intervention were enrolled. All plaques were detected in culprit vessels using CTA, and total plaque volume (TPV) and OCT features were assessed at the corresponding sites. All plaques were divided into three groups according to the tertile levels of TPV (low TPV: <96.5 ​mm3, moderate TPV: 96.5-164.7 ​mm3, high TPV: ≥164.8 ​mm3).

RESULTS

A total of 990 plaques were imaged by OCT in 419 patients: 445 plaques in 190 (45.3%) patients with ACS and 545 in 229 (54.7%) with CCS. Macrophage was more prevalent in plaques with greater TPV in patients who presented with ACS but not in those who presented with CCS (low vs. moderate vs. high TPV group: macrophage 57.4% vs. 71.8% vs. 82.4% in ACS; 63.4% vs. 67.8% vs. 66.7% in CCS; interaction P ​= ​0.004). Lipid arc increased as TPV increased, especially in patients who presented with ACS. Conversely, the layer index increased as TPV increased in patients with CCS.

CONCLUSION

Greater plaque burden was closely related to higher levels of plaque vulnerability in ACS and greater volume of layered plaque in CCS.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT04523194.

Polarization-insensitive optical coherence tomography using pseudo-depolarized reference light for mitigating birefringence-related image artifacts

Significance

Optical coherence tomography (OCT) images are prone to image artifacts due to the birefringence of the sample or the optical system when a polarized light source is used for imaging. These artifacts can lead to degraded image quality and diagnostic information.

Aim

We aim to mitigate these birefringence-related artifacts in OCT images by adding a depolarizer module in the reference arm of the interferometer.

Approach

We investigated different configurations of liquid crystal patterned retarders as pseudo-depolarizers in the reference arm of OCT setups. We identified the most effective depolarization module layout for polarization artifact suppression for a spectral-domain OCT system based on a Michelson and a Mach-Zehnder interferometer.

Results

The performance of our approach was demonstrated in an achromatic quarter-wave plate allowing the selection of a variety of sample polarization states. A substantial improvement of the OCT signal magnitude was observed after placing the optimal depolarizer configuration, reducing the cross-polarization artifact from 5.7 to 1.8 dB and from 8.0 to 1.0 dB below the co-polarized signal for the fiber-based Michelson and Mach-Zehnder setup, respectively. An imaging experiment in the birefringent scleral tissue of a post-mortem alpine marmot eye and a mouse tail specimen further showcased a significant improvement in the detected signal intensity and an enhanced OCT image quality followed by a drastic elimination of the birefringence-related artifacts.

Conclusions

Our study presents a simple yet cost-effective technique to mitigate birefringence-related artifacts in OCT imaging. This method can be readily implemented in existing OCT technology and improve the effectiveness of various OCT imaging applications in biomedicine.

Three-dimensional optical coherence tomography for guidance of percutaneous coronary intervention for coronary bifurcation disease: a review of current clinical applications

Percutaneous coronary intervention (PCI) for coronary bifurcation disease remains one of the most challenging situations in interventional cardiology in terms of procedural success rates and long-term cardiac events. Optical coherence tomography (OCT), with a higher signal-to-noise ratio and the ability to distinguish plaque components, can display the true condition of bifurcation lesions without overlapping or shortening and achieve detailed visualization of vascular structures, which is superior to those of other imaging modalities. Three-dimensional (3D) reconstruction of OCT images (3D-OCT) helps to gain a more informed understanding of the geometry and morphology of bifurcation lesions and provide additive information on plaque distribution. Following stent implantation, 3D-OCT can also guide the re-crossing of guide wires through stent struts jailing the side branch (SB) ostium and more clearly display the jailing strut configuration, as well as the ideal position of the guidewire recrossing point and stent struct link connection, to confirm the optimal guidewire position and understand interactions between stents and vessel walls, which may improve clinical results after PCI. The present review provides an up-to-date overview of the clinical use of 3D-OCT for accurate assessment of bifurcation anatomy, guiding the optimal guidewire rewiring into SB during bifurcation stenting, and evaluation of post-PCI results, offering novel information about atherosclerotic disease or stenting process.

Predictors of Optical Coherence Tomography-Defined Calcified Nodules in Patients With Acute Coronary Syndrome - A Substudy From the TACTICS Registry

BACKGROUND

Recent studies suggest that the presence of calcified nodules (CN) is associated with worse prognosis in patients with acute coronary syndrome (ACS). We investigated clinical predictors of optical coherence tomography (OCT)-defined CN in ACS patients in a prospective multicenter registry.

METHODS AND RESULTS

We investigated 695 patients enrolled in the TACTICS registry who underwent OCT assessment of the culprit lesion during primary percutaneous coronary intervention. OCT-CN was defined as calcific nodules erupting into the lumen with disruption of the fibrous cap and an underlying calcified plate. Compared with patients without OCT-CN, patients with OCT-CN (n=28) were older (mean [±SD] age 75.0±11.3 vs. 65.7±12.7 years; P<0.001), had a higher prevalence of diabetes (50.0% vs. 29.4%; P=0.034), hemodialysis (21.4% vs. 1.6%; P<0.001), and Killip Class III/IV heart failure (21.4% vs. 5.7%; P=0.003), and a higher preprocedural SYNTAX score (median [interquartile range] score 15 [11-25] vs. 11 [7-19]; P=0.003). On multivariable analysis, age (odds ratio [OR] 1.072; P<0.001), hemodialysis (OR 16.571; P<0.001), and Killip Class III/IV (OR 4.466; P=0.004) were significantly associated with the presence of OCT-CN. In non-dialysis patients (n=678), age (OR 1.081; P<0.001), diabetes (OR 3.046; P=0.014), and Killip Class III/IV (OR 4.414; P=0.009) were significantly associated with the presence of OCT-CN.

CONCLUSIONS

The TACTICS registry shows that OCT-CN is associated with lesion severity and poor clinical background, which may worsen prognosis.

Activatable fluorescent probes for atherosclerosis theranostics

The onset of atherosclerosis (AS) is insidious, and early stage patients have atypical clinical symptoms. After being diagnosed in late stage, it is often prone to sudden and fatal cardiovascular events. Therefore, it is highly desirable to develop precise and efficient diagnosis and therapy strategies of AS. Benefiting from high signal-to-noise ratio, low detection limit, high specificity and sensitivity, a series of activatable fluorescent probes based on atherosclerotic microenvironment have emerged for identification and treatment of AS. In this review, we focus on the atherosclerotic microenvironment and briefly summarize the correlation between the structural transformation and fluorescence signal changes of mono-/double-activatable fluorescent probes upon biomarkers stimulation. Moreover, their cutting-edge progress for AS theranostics is described. Finally, the outlook for activatable theranostic probes based on atherosclerotic microenvironment is discussed to aim at promoting innovative research in imaging-guided precise AS therapy.

High accuracy patient-specific 3D coronary reconstruction from angiography and intravascular optical coherence tomography

The integration of digital subtraction angiography (DSA) with intravascular optical coherence tomography (IVOCT) offers a comprehensive 3D arterial model, which is invaluable for the analysis of vascular anatomy and biomechanics. However, the process of image fusion is often hindered by the challenge of accurately orienting IVOCT images. This paper introduces a novel, to our knowledge, dual-path 3D reconstruction method that leverages the guidewire and the vessel's centerline to establish cross sectional direction vectors within the IVOCT images and spatial direction vectors along the guidewire's trajectory. This approach minimizes the accumulation of reconstruction errors by ensuring the precise orientation of each vascular cross section. The efficacy of the proposed method is validated through vascular phantom experiments and the reconstruction of patient-specific 3D coronary models.

Relationship Between Calcified Plaque Burden, Vascular Inflammation, and Plaque Vulnerability in Patients With Coronary Atherosclerosis

BACKGROUND

Coronary artery calcification is an integral part of atherosclerosis. It has been suggested that early coronary artery calcification is associated with active inflammation, and advanced calcification forms as inflammation subsides. Inflammation is also an important factor in plaque vulnerability. However, the relationship between coronary artery calcium burden, vascular inflammation, and plaque vulnerability has not been fully investigated.

OBJECTIVES

This study aimed to correlate calcified plaque burden (CPB) at the culprit lesion with vascular inflammation and plaque vulnerability.

METHODS

Patients with coronary artery disease who had both computed tomography angiography and optical coherence tomography were included. The authors divided the patients into 4 groups: 1 group without calcification at the culprit lesion; and 3 groups based on the CPB tertiles. CPB was calculated as calcified plaque volume divided by vessel volume in the culprit lesion. The authors compared pericoronary adipose tissue (PCAT) attenuation for vascular inflammation and optical coherence tomography-derived vulnerable features among the 4 groups.

RESULTS

Among 578 patients, the highest CPB tertile showed significantly lower PCAT attenuation of culprit vessel compared with the other groups. The prevalence of features of plaque vulnerability (including lipid-rich plaque, macrophage, and microvessel) was also lowest in the highest CPB tertile. In the patients with calcification, higher age, statin use, and lower PCAT attenuation were independently associated with CPB.

CONCLUSIONS

Greater calcium burden is associated with a lower level of vascular inflammation and plaque vulnerability. A greater calcium burden may represent advanced stable plaque without significant inflammatory activity. (Massachusetts General Hospital and Tsuchiura Kyodo General Hospital Coronary Imaging Collaboration; NCT04523194).

Sex differences in plaque characteristics of fractional flow reserve-negative non-culprit lesions after myocardial infarction

BACKGROUND AND AIMS

Recurrent events after myocardial infarction (MI) are common and often originate from native non-culprit (NC) lesions that are non-flow limiting. These lesions consequently pose as targets to improve long-term outcome. It is, however, largely unknown whether these lesions differ between sexes. The aim of this study was to assess such potential differences.

METHODS

From the PECTUS-obs study, we assessed sex-related differences in plaque characteristics of fractional flow reserve (FFR)-negative intermediate NC lesions in 420 MI-patients.

RESULTS

Among the included patients, 80 (19.1 %) were female and 340 (80.9 %) male. Women were older and more frequently had hypertension and diabetes. In total, 494 NC lesions were analyzed. After adjustment for clinical characteristics and accounting for within-patients clustering, lesion length was longer in female patients (20.8 ± 10.0 vs 18.3 ± 8.5 mm, p = 0.048) and minimum lumen area (2.30 ± 1.42 vs 2.78 ± 1.54 mm2, p < 0.001) and minimum lumen diameter (1.39 ± 0.45 vs 1.54 ± 0.44 mm, p < 0.001) were smaller. The minimum fibrous cap thickness was smaller among females (96 ± 53 vs 112 ± 72 μm, p = 0.025), with more lesions harboring a thin cap fibroatheroma (39.3 % vs 24.9 %, p < 0.001). Major adverse cardiovascular events at two years occurred in 6.3 % of female patients and 11.8 % of male patients (p = 0.15).

CONCLUSIONS

FFR-negative NC lesions after MI harbored more high-risk plaque features in female patients. Although this did not translate into an excess of recurrent events in female patients in this modestly sized cohort, it remains to be investigated whether this difference affects clinical outcome.

Revealing the nature of cardiovascular disease using DERGA, a novel data ensemble refinement greedy algorithm

BACKGROUND

The study aimed to determine the most crucial parameters associated with CVD and employ a novel data ensemble refinement procedure to uncover the optimal pattern of these parameters that can result in a high prediction accuracy.

METHODS AND RESULTS

Data were collected from 369 patients in total, 281 patients with CVD or at risk of developing it, compared to 88 otherwise healthy individuals. Within the group of 281 CVD or at-risk patients, 53 were diagnosed with coronary artery disease (CAD), 16 with end-stage renal disease, 47 newly diagnosed with diabetes mellitus 2 and 92 with chronic inflammatory disorders (21 rheumatoid arthritis, 41 psoriasis, 30 angiitis). The data were analyzed using an artificial intelligence-based algorithm with the primary objective of identifying the optimal pattern of parameters that define CVD. The study highlights the effectiveness of a six-parameter combination in discerning the likelihood of cardiovascular disease using DERGA and Extra Trees algorithms. These parameters, ranked in order of importance, include Platelet-derived Microvesicles (PMV), hypertension, age, smoking, dyslipidemia, and Body Mass Index (BMI). Endothelial and erythrocyte MVs, along with diabetes were the least important predictors. In addition, the highest prediction accuracy achieved is 98.64%. Notably, using PMVs alone yields a 91.32% accuracy, while the optimal model employing all ten parameters, yields a prediction accuracy of 0.9783 (97.83%).

CONCLUSIONS

Our research showcases the efficacy of DERGA, an innovative data ensemble refinement greedy algorithm. DERGA accelerates the assessment of an individual's risk of developing CVD, allowing for early diagnosis, significantly reduces the number of required lab tests and optimizes resource utilization. Additionally, it assists in identifying the optimal parameters critical for assessing CVD susceptibility, thereby enhancing our understanding of the underlying mechanisms.

Optical Coherence Tomography in Myocardial Infarction Management: Enhancing Precision in Percutaneous Coronary Intervention

In acute myocardial infarction (AMI), the urgency of coronary revascularization through percutaneous coronary intervention (PCI) is paramount, offering notable advantages over pharmacologic treatment. However, the persistent risk of adverse events, including recurrent AMI and heart failure post-revascularization, underscores the necessity for enhanced strategies in managing coronary artery disease. Traditional angiography, while widely employed, presents significant limitations by providing only two-dimensional representations of complex three-dimensional vascular structures, hampering the accurate assessment of plaque characteristics and stenosis severity. Intravascular imaging, specifically optical coherence tomography (OCT), significantly addresses these limitations with superior spatial resolution compared to intravascular ultrasound (IVUS). Within the context of AMI, OCT serves dual purposes: as a diagnostic tool to accurately identify culprit lesions in ambiguous cases and as a guide for optimizing PCI procedures. Its capacity to differentiate between various mechanisms of acute coronary syndrome, such as plaque rupture and spontaneous coronary dissection, enhances its diagnostic potential. Furthermore, OCT facilitates precise lesion preparation, optimal stent sizing, and confirms stent deployment efficacy. Recent meta-analyses indicate that OCT-guided PCI markedly improves safety and efficacy in revascularization, subsequently decreasing the risks of mortality and complications. This review emphasizes the critical role of OCT in refining patient-specific therapeutic approaches, aligning with the principles of precision medicine to enhance clinical outcomes for individuals experiencing AMI.

Effect of Colchicine on Coronary Plaque Stability in Acute Coronary Syndrome as Assessed by Optical Coherence Tomography: The COLOCT Randomized Clinical Trial

BACKGROUND

Colchicine has been approved to reduce cardiovascular risk in patients with coronary heart disease on the basis of its potential benefits demonstrated in the COLCOT (Colchicine Cardiovascular Outcomes Trial) and LoDoCo2 (Low-Dose Colchicine 2) studies. Nevertheless, there are limited data available about the specific impact of colchicine on coronary plaques.

METHODS

This was a prospective, single-center, randomized, double-blind clinical trial. From May 3, 2021, until August 31, 2022, a total of 128 patients with acute coronary syndrome aged 18 to 80 years with lipid-rich plaque (lipid pool arc >90°) detected by optical coherence tomography were included. The subjects were randomly assigned in a 1:1 ratio to receive either colchicine (0.5 mg once daily) or placebo for 12 months. The primary end point was the change in the minimal fibrous cap thickness from baseline to the 12-month follow-up.

RESULTS

Among 128 patients, 52 in the colchicine group and 52 in the placebo group completed the study. The mean age of the 128 patients was 58.0±9.8 years, and 25.0% were female. Compared with placebo, colchicine therapy significantly increased the minimal fibrous cap thickness (51.9 [95% CI, 32.8 to 71.0] μm versus 87.2 [95% CI, 69.9 to 104.5] μm; difference, 34.2 [95% CI, 9.7 to 58.6] μm; P=0.006), and reduced average lipid arc (-25.2° [95% CI, -30.6° to -19.9°] versus -35.7° [95% CI, -40.5° to -30.8°]; difference, -10.5° [95% CI, -17.7° to -3.4°]; P=0.004), mean angular extension of macrophages (-8.9° [95% CI, -13.3° to -4.6°] versus -14.0° [95% CI, -18.0° to -10.0°]; difference, -6.0° [95% CI, -11.8° to -0.2°]; P=0.044), high-sensitivity C-reactive protein level (geometric mean ratio, 0.6 [95% CI, 0.4 to 1.0] versus 0.3 [95% CI, 0.2 to 0.5]; difference, 0.5 [95% CI, 0.3 to 1.0]; P=0.046), interleukin-6 level (geometric mean ratio, 0.8 [95% CI, 0.6 to 1.1] versus 0.5 [95% CI, 0.4 to 0.7]; difference, 0.6 [95% CI, 0.4 to 0.9]; P=0.025), and myeloperoxidase level (geometric mean ratio, 1.0 [95% CI, 0.8 to 1.2] versus 0.8 [95% CI, 0.7 to 0.9]; difference, 0.8 [95% CI, 0.6 to 1.0]; P=0.047).

CONCLUSIONS

Our findings suggested that colchicine resulted in favorable effects on coronary plaque stabilization at optical coherence tomography in patients with acute coronary syndrome.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04848857.

Derivation and external validation of mass spectrometry-based proteomic model using machine learning algorithms to predict plaque rupture in patients with acute coronary syndrome

BACKGROUND

A poor prognosis is associated with atherosclerotic plaque rupture (PR) despite after conventional therapy for patients with acute coronary syndrome (ACS). Timely identification of PR improves the risk stratification and prognosis of ACS patients.

METHODS

A derivation cohort of 110 patients with ACS who underwent pre-intervention optical coherence tomography (OCT) were matched 1:1 to the PR and intact fibrous cap (IFC) groups according to traditional risk factors. Candidate PR proteins were identified via mass spectrometry (MS)-based proteomics using unbiased machine learning methods and were further validated by enzyme-linked immunosorbent assay (ELISA) in an external validation cohort of 85 patients with ACS. The performance of candidate biomakers was assessed using the receiver operating characteristic curve analysis.

RESULTS

1121 proteins were identified and 535 filtered proteins were used for analysis. Nine candidate proteins were screened by five machine learning algorithms. Three proteins (APOC3, RAB39A, and KNG1) were significantly different between the PR and IFC in validation cohort. The performance of plasm APOC3, RAB39A, and KNG1 for differentiating PR and IFC was superior to that of the conventional biomarkers and risk factors.

CONCLUSION

The proteins (APOC3, RAB39A, and KNG1) serve as a potential novel diagnostic tool to identify PR in ACS patients.

Motor-free telerobotic endomicroscopy for steerable and programmable imaging in complex curved and localized areas

Intraluminal epithelial abnormalities, potential precursors to significant conditions like cancer, necessitate early detection for improved prognosis. We present a motor-free telerobotic optical coherence tomography (OCT) endoscope that offers high-resolution intraluminal imaging and overcomes the limitations of traditional systems in navigating curved lumens. This system incorporates a compact magnetic rotor with a rotatable diametrically magnetized cylinder permanent magnet (RDPM) and a reflector, effectively mitigating thermal and electrical risks by utilizing an external magnetic field to maintain temperature increases below 0.5 °C and generated voltage under 0.02 mV. Additionally, a learning-based method corrects imaging distortions resulting from nonuniform rotational speeds. Demonstrating superior maneuverability, the device achieves steerable angles up to 110° and operates effectively in vivo, providing distortion-free 3D programmable imaging in mouse colons. This advancement represents a significant step towards guidewire-independent endomicroscopy, enhancing both safety and potential patient outcomes.

Update on cardiac imaging: A critical analysis

Imaging is instrumental in diagnosing and directing the management of atherosclerosis. In 1958 the first diagnostic coronary angiography (CA) was performed, and since then further development has led to new methods such as coronary CT angiography (CTA), optical coherence tomography (OCT), positron tomography (PET), and intravascular ultrasound (IVUS). Currently, CA remains powerful for visualizing coronary arteries; however, recent studies show the benefits of using other non-invasive techniques. This review identifies optimum imaging techniques for diagnosing and monitoring plaque stability. This becomes even direr now, given the rapidly rising incidence of atherosclerosis in society today. Many acute coronary events, including acute myocardial infarctions and sudden deaths, are attributable to plaque rupture. Although fatal, these events can be preventable. We discuss the factors affecting plaque integrity, such as increased inflammation, medications like statins, and increased lipid content. Some of these precipitating factors are identifiable through imaging. However, we also highlight significant complications arising in some modalities; in CA this can include ventricular arrhythmia and even death. Extending this, we elucidated from the literature that risk can also vary based on the location of arteries and their plaques. Promisingly, there are less invasive methods being trialled for assessing plaque stability, such as Cardiac Magnetic Resonance Imaging (CMR), which is already in use for other cardiac diseases like cardiomyopathies. Therefore, future research focusing on using imaging modalities in conjunction may be sensible, to bridge between the effectiveness of modalities, at the expense of increased complications, and vice versa.

PneumaOCT: Pneumatic optical coherence tomography endoscopy for targeted distortion-free imaging in tortuous and narrow internal lumens

The complex anatomy of internal luminal organs, like bronchioles, poses challenges for endoscopic optical coherence tomography (OCT). These challenges include limited steerability for targeted imaging and nonuniform rotation distortion (NURD) with proximal scanning. Using rotary micromotors for distal scanning could address NURD but raises concerns about electrical safety and costs. We present pneumaOCT, the first pneumatic OCT endoscope, comprising a steerable catheter with a soft pneumatic actuator and an imaging probe with a miniature pneumatic turbine. With a diameter of 2.8 mm, pneumaOCT allows for a bending angle of up to 237°, facilitating navigation through narrow turns. The pneumatic turbine enables adjustable imaging speeds from 51 to 446 revolutions per second. We demonstrate the pneumaOCT in vivo imaging of mouse esophagus and colon, as well as targeted and distortion-free imaging of peripheral bronchioles in a bronchial phantom and a porcine lung. This advancement substantially improves endoscopic OCT for navigational imaging in curved and narrow lumens.

Three-Dimensionally Printed Elastic Cardiovascular Phantoms for Carotid Angioplasty Training and Personalized Healthcare

Background/Objective: Atherosclerosis is becoming increasingly common in modern society. Owing to the increasing number of complex angioplasty procedures, there is an increasing need for training in cases where the risk of periprocedural complications is high. Methods: A procedure was developed to obtain three-dimensional (3D) models and printing of blood vessels. The mechanical and optical properties of the printed materials were also examined. Angioplasty and stent implantation were tested, and the phantom was compared with the clinical data of patients who underwent interventional treatment. Both laser techniques and cone-beam computed tomography of the phantoms were used for comparison. Results: The printed material exhibited mechanical parameters similar to those of blood vessel walls. The refractive index of 1.473 ± 0.002 and high transparency allowed for non-invasive laser examination of the interior of the print. The printed models behaved similarly to human arteries in vivo, allowing training in treatment procedures and considering vessel deformation during the procedure. Models with stents can be analyzed using laser and cone-beam computed tomography to compare stents from different manufacturers. Conclusions: The developed methodology allows for simple and time-efficient production of personalized vessel phantoms.

Multimodal Imaging-Assisted Intravascular Theranostic Photoactivation on Atherosclerotic Plaque

BACKGROUND

Atherosclerosis is a chronic inflammatory disease causing a fatal plaque rupture, and its key aspect is a failure to resolve inflammation. We hypothesize that macrophage-targeted near-infrared fluorescence emitting photoactivation could simultaneously assess macrophage/lipid-rich plaques in vivo and facilitate inflammation resolution.

METHODS

We fabricated a Dectin-1-targeted photoactivatable theranostic agent through the chemical conjugation of the near-infrared fluorescence-emitting photosensitizer chlorin e6 and the Dectin-1 ligand laminarin (laminarin-chlorin e6 [LAM-Ce6]). Intravascular photoactivation by a customized fiber-based diffuser after administration of LAM-Ce6 effectively reduced inflammation in the targeted plaques of atherosclerotic rabbits in vivo as serially assessed by dual-modal optical coherence tomography-near-infrared fluorescence structural-molecular catheter imaging after 4 weeks.

RESULTS

The number of apoptotic macrophages peaked at 1 day after laser irradiation and then resolved until 4 weeks. Autophagy was strongly augmented 1 hour after the light therapy, with the formation of autophagolysosomes. LAM-Ce6 photoactivation increased the terminal deoxynucleotidyl transferase dUTP (deoxyuridine triphosphate) nick end labeling/RAM11 (rabbit monocyte/macrophage antibody)- and MerTK (c-Mer tyrosine kinase)-positive cells in the plaques, suggesting enhanced efferocytosis. In line with inflammation resolution, photoactivation reduced the plaque burden through fibrotic replacement via the TGF (transforming growth factor)-β/CTGF (connective tissue growth factor) pathway.

CONCLUSIONS

Optical coherence tomography-near-infrared fluorescence imaging-guided macrophage Dectin-1-targetable photoactivation could induce the transition of macrophage/lipid-rich plaques into collagen-rich lesions through autophagy-mediated inflammation resolution and TGF-β-dependent fibrotic replacement. This novel strategy offers a new opportunity for the catheter-based theranostic strategy.