Comparison of Intensive Versus Moderate Lipid-Lowering Therapy on Fibrous Cap and Atheroma Volume of Coronary Lipid-Rich Plaque Using Serial Optical Coherence Tomography and Intravascular Ultrasound Imaging

Safety and efficacy of PCSK9 inhibitor (evolocumab) in patients with non-ST segment elevation acute coronary syndrome and non-culprit artery critical lesions: a randomised controlled trial protocol (SPECIAL study)

INTRODUCTION

Patients with non-ST segment elevation acute coronary syndrome (NSTE-ACS) and concomitant multivessel coronary artery disease (CAD) are considered patients with extremely high-risk atherosclerotic cardiovascular disease (ASCVD), and current guidelines specify a lower low-density lipoprotein cholesterol (LDL-C) target for this population. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have been shown to effectively reduce LDL-C levels on a statin background. Additionally, several studies have confirmed the role of PCSK9 inhibitors in plaque regression and reducing residual cardiovascular risk in patients with ACS. However, those studies included coronary lesions with a degree of stenosis <50%. Whether the application of PCSK9 inhibitors in patients with NSTE-ACS with non-culprit artery critical lesions (stenosis degree between 50% and 75%) has a similar effect on plaque regression and improvement of cardiovascular outcomes remains unknown, with a lack of relevant research. This study aims to further investigate the safety and efficacy of evolocumab in patients with NSTE-ACS and concomitant multivessel CAD (non-culprit artery stenosis between 50% and 75%).

METHODS AND ANALYSIS

In this single-centre clinical randomised controlled trial, 122 patients with NSTE-ACS and concomitant multivessel CAD (non-culprit artery stenosis between 50% and 75%) will be randomly assigned to either the evolocumab treatment group or the standard treatment group after completing culprit vessel revascularisation. The evolocumab treatment group will receive evolocumab in addition to statin therapy, while the standard treatment group will receive standard statin therapy. At baseline and week 50, patients in the evolocumab treatment group will undergo coronary angiography and OCT imaging to visualise pre-existing non-lesional vessels. The primary end point is the absolute change in average minimum fibrous cap thickness (FCT) from baseline to week 50. Secondary end points include changes in plaque lipid arc, lipid length, macrophage grading, lipid levels and major adverse cardiovascular events during the 1-year follow-up period.

ETHICS AND DISSEMINATION

Ethics: this study will adhere to the principles outlined in the Helsinki Declaration and other applicable ethical guidelines. This study protocol has received approval from the Medical Research Ethics Committee of the First Affiliated Hospital of the University of Science and Technology of China (Anhui Provincial Hospital), with approval number 2022-ky214.

DISSEMINATION

we plan to disseminate the findings of this study through various channels. This includes publication in peer-reviewed academic journals, presentation at relevant academic conferences and communication to the public, policymakers and healthcare professionals. We will also share updates on the research progress through social media and other online platforms to facilitate the exchange and application of scientific knowledge. Efforts will be made to ensure widespread dissemination of the research results and to have a positive impact on society.

TRIAL REGISTRATION NUMBER

ChiCTR2200066675.

Drug intervention as an emerging concept for secondary prevention in patients with coronary disease

Non-culprit lesion-related coronary events are a significant concern in patients with coronary artery disease (CAD) undergoing coronary intervention. Since several studies using intra-coronary imaging modalities have reported a high prevalence of vulnerable plaques in non-culprit lesions at the initial coronary event, the immediate stabilization of these plaques by intensive pharmacological regimens may contribute to the reduction in the adverse events. Although current treatment guidelines recommend the titration of statin and other drugs to attain the treatment goal of low-density lipoprotein cholesterol (LDL-C) level in patients with CAD, the early prescription of strong LDL-C lowering drugs with more intensive regimen may further reduce the incidence of recurrent cardiovascular events. In fact, several studies with intensive regimen have demonstrated a higher percentage of patients with the attainment of LDL-C treatment goal in the early phase following discharge. In addition to many imaging studies showing plaque stabilization by LDL-C lowering drugs, several recent reports have shown the efficacy of early statin and proprotein convertase subtilisin/kexin type 9 inhibitors on the immediate stabilization of non-culprit coronary plaques. To raise awareness regarding this important concept of immediate plaque stabilization and subsequent reduction in the incidence of recurrent coronary events, the term 'Drug Intervention' has been introduced and gradually applied in the clinical field, although a clear definition is lacking. The main target of this concept is patients with acute coronary syndrome as a higher prevalence of vulnerable plaques in non-culprit lesions in addition to the worse clinical outcomes has been reported in recent imaging studies. In this article, we discuss the backgrounds and the concept of drug intervention.

Thin-cap fibroatheroma in acute coronary syndrome: Implication for intravascular imaging assessment

Acute coronary syndrome (ACS), a significant cardiovascular disease threat, has garnered increased focus concerning its etiological mechanisms. Thin-cap fibroatheroma (TCFA) are central to ACS pathogenesis, characterized by lipid-rich plaques, profuse foam cells, cholesterol crystals, and fragile fibrous caps predisposed to rupture. While TCFAs may be latent and asymptomatic, their pivotal role in ACS risk is undeniable. High-resolution imaging techniques like Optical coherence tomography (OCT) and Intravascular ultrasound (IVUS) are instrumental for effective TCFA detection. Therapeutic strategies encompass pharmacological and interventional measures, including antiplatelet agents, statins, and Percutaneous Coronary Intervention (PCI), aiding in plaque stabilization, inflammation reduction, and rupture risk mitigation. Despite the strong correlation between TCFAs and adverse prognoses in ACS patients, early detection and rigorous treatment significantly enhance patient prognosis and diminish cardiovascular events. This review aims to encapsulate recent advancements in TCFA research within ACS, covering formation mechanisms, clinical manifestations, and prognostic implications.

Impact of PCSK9 inhibitors on coronary atheroma phenotype following myocardial infarction: insights from intravascular imaging

PURPOSE OF REVIEW

The aim of this study was to review the impact of combination lipid lowering with statins and proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors on coronary atherosclerosis using serial intravascular imaging.

RECENT FINDINGS

Early studies using intravascular ultrasound established the ability of increasingly intensive lipid lowering to both slow progression and ultimately promote regression of coronary disease. More recent clinical trials that have employed serial imaging with optical coherence tomography have permitted the ability to evaluate the impact of intensive lipid lowering on compositional features associated with plaque vulnerability. In particular, the combination of intensive statin and PCSK9 inhibitor therapy promotes plaque stability in patients following an acute coronary syndrome.

SUMMARY

More intensive lipid lowering using the combination of statins and PCSK9 inhibitors promote plaque regression in addition to promoting calcification, fibrous cap thickening and reductions in plaque lipid. These plaque-stabilizing effects underscore the benefits of combination therapy on cardiovascular events and highlight the importance of combination lipid-lowering therapy.

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.

Impact of lipid lowering on coronary atherosclerosis moving from the lumen to the artery wall

Randomized clinical trials have demonstrated that increasingly intensive lowering of low-density lipoprotein cholesterol (LDL-C) reduces the rate of cardiovascular events in the primary and secondary prevention setting. Integration of serial coronary imaging within clinical trials has enabled evaluation of medical therapies on the natural history of coronary disease. These studies have extended from early investigation of coronary obstruction with angiography to more contemporary evaluation of plaque burden and composition with imaging modalities that directly visualize the artery wall. The findings of these trials have demonstrated that intensive lipid lowering promotes plaque regression and stabilization. The lessons of this body of research provide a biological rationale underscoring the ability of intensive lipid lowering to reduce cardiovascular risk and have the potential to promote greater uptake in clinical practice.

Intensive lipid lowering agents and coronary atherosclerosis: Insights from intravascular imaging

Advances in intravascular imaging have permitted comprehensive evaluation of coronary atherosclerotic plaque from the perspective of its burden and individual components. These advances have been integrated in clinical trials that have evaluated the impact of intensive lipid lowering regimens. These trials have demonstrated that intensive lipid lowering, using high dose statins as monotherapy and in combination with new lipid lowering agents, produce favorable effects on coronary atheroma, resulting in regression and stabilization. These findings provide important biological insights to understand how intensive lipid lowering may reduce cardiovascular risk. This review aims to provide the reader with a contemporary overview of the findings of these studies and to propose the potential clinical implications for management of higher risk patients with atherosclerotic coronary artery disease.

Fibrous Cap Thickness Predicts Stable Coronary Plaque Progression: Early Clinical Validation of a Semiautomated OCT Technology

BACKGROUND

Imaging-based characteristics associated with the progression of stable coronary atherosclerotic lesions are poorly defined. Utilizing a combination of optical coherence tomography (OCT) and intravascular ultrasound (IVUS) imaging, we aimed to characterize the lesions prone to progression through clinical validation of a semiautomated OCT computational program.

METHODS

Patients with stable coronary artery disease underwent nonculprit vessel imaging with IVUS and OCT at baseline and IVUS at the 12-month follow-up. After coregistration of baseline and follow-up IVUS images, paired 5-mm segments from each patient were identified, demonstrating the greatest plaque progression and regression as measured by the change in plaque burden. Experienced readers identified plaque features on corresponding baseline OCT segments, and predictors of plaque progression were assessed by multivariable analysis. Each segment then underwent volumetric assessment of the fibrous cap (FC) using proprietary software.

RESULTS

Among 23 patients (70% men; median age, 67 years), experienced-reader analysis demonstrated that for every 100 μm increase in mean FC thickness, plaques were 87% less likely to progress (P = .01), which persisted on multivariable analysis controlling for baseline plaque burden (P = .05). Automated FC analysis (n = 17 paired segments) confirmed this finding (P = .01) and found thinner minimal FC thickness (P = .01) and larger FC surface area of <65 μm (P = .02) and <100 μm (P = .04) in progressing segments than in regressing segments. No additional imaging features predicted plaque progression.

CONCLUSIONS

A semiautomated FC analysis tool confirmed the significant association between thinner FC and stable coronary plaque progression along entire vessel segments, illustrating the diffuse nature of FC thinning and suggesting a future clinical role in predicting the progression of stable coronary artery disease.

Clinical Course of Optical Coherence Tomography-Detected Lipid-Rich Coronary Plaque After Optimal Medical Therapy

Background: The aim of this study was to evaluate optical coherence tomography (OCT)-detected lipid-rich coronary plaques (LRCPs) with coronary computed tomography angiography (CCTA) 10 months after optimal medical therapy (OMT).

Methods and Results: Baseline OCT detected 28 LRCPs in non-culprit lesions. High-risk plaque features (HRPFs), such as positive remodeling, very low attenuation plaques, napkin-ring sign, and spotty calcification, were observed in 67.9%, 67.9%, 21.4%, and 64.3% of LRCPs, respectively, at the 10-month follow-up CCTA. Lesions with ≥3 HRPFs were defined as high-risk LRCPs (n=12); the remaining were defined as low-risk LRCPs (n=16). The maximum lipid arc on baseline OCT was larger in high- than low-risk LRCPs (221±62° vs. 179±44°, respectively; P=0.04). Receiver operating characteristic curve analysis indicated that a maximum lipid arc >154° on baseline OCT was the optimal cut-off value to predict high-risk LRCPs 10 months after OMT. Patients with high-risk LRCPs had worse clinical outcomes, defined as a composite of cardiac death, target lesion-related myocardial infarction, and target lesion-related revascularization, during follow-up than those with low-risk LRCPs (33.3% vs. 0%; P=0.01).

Conclusions: A high-risk LRCP at follow-up CCTA was correlated with a larger maximum lipid arc on baseline OCT. Further aggressive treatment for patients with large LRCPs may reduce vulnerable plaque features and prevent future cardiac events.

In vivo evidence of atherosclerotic plaque erosion and healing in patients with acute coronary syndrome using serial optical coherence tomography imaging

BACKGROUND

The EROSION study (Effective Anti-Thrombotic Therapy Without Stenting: Intravascular Optical Coherence Tomography-Based Management in Plaque Erosion) allowed us to observe the healing process of coronary plaque erosion in vivo. The present study aimed to investigate the incidence of newly formed healed plaque and different baseline characteristics of acute coronary syndrome (ACS) patients caused by plaque erosion with or without newly formed healed plaque using optical coherence tomography (OCT).

METHODS

A total of 137 ACS patients with culprit plaque erosion who underwent pre-intervention OCT imaging and received no stent implantation were enrolled. Patients were stratified according to the presence or absence of newly formed healed phenotype at 1-month (137 patients) or 1-year OCT follow-up (52 patients). Patient's baseline clinical, angiographic, OCT characteristics and outcomes were compared.

RESULTS

There were 55.5% (76/137) of patients developed healed plaque at 1 month, and 69.2% (36/52) of patients developed healed plaque at 1 year. Patients with newly formed healed plaque had larger thrombus burden, and lower degree of area stenosis (AS%) at baseline than those without, and thrombus burden and AS% were predictors of plaque healing. The healing process was accompanied by the significant increase of AS% and incidence of microchannels, and greater inflammatory response. The outcomes appeared to be similar between the two groups.

CONCLUSIONS

Newly formed healed plaque was found in more than half of ACS patients with plaque erosion without stenting. Patients with newly formed healed plaque had lower luminal stenosis and larger thrombus burden. During healing process, luminal stenosis increased gradually.

Association of Contemporary Statin Pretreatment Intensity and LDL-C Levels on the Incidence of STEMI Presentation

Constituting hypolipidemic and pleiotropic effects, statins stabilize coronary artery plaque and may prevent STEMI events. This study investigated the association between contemporary statin pretreatment intensity, low-density lipoprotein cholesterol (LDL-C) levels, and the type of acute coronary syndrome (ACS) presentation: STEMI vs. NSTE-ACS. Data were drawn from the ACS Israeli Survey (ACSIS), a biennial prospective national survey that took place in 2008–2018. The rate of STEMI vs. NSTE-ACS was calculated by statin use, including statin intensity (high-intensity statin therapy (HIST) and low-intensity statin therapy (LIST) prior to the index ACS event. Among 5103 patients, 2839 (56%) were statin-naive, 1389 (27%) used LIST and 875 (17%) used HIST. Statin pretreated patients were older and had a higher rates of co-morbidities, cardiovascular disease history and pretreatment with evidence-based medications. STEMI vs. NSTE-ACS was lower among HIST vs. LIST vs. statin-naive patients (31.0%, 37.8%, and 54.0%, respectively, p for trend < 0.001). Multivariate analysis revealed that HIST was independently associated with lower STEMI presentation (OR_adj 0.70; 95% CI 0.57–0.86), while LIST (OR_adj 0.92; 95% CI 0.77–1.10) and LDL-C < 70 mg/dL (OR_adj 0.96; 95% CI 0.82–1.14) were not. In conclusion, among patients admitted with ACS, pretreatment with HIST was independently associated with a lower probability of STEMI presentation, while LIST and LDL-C < 70 mg/dL were not.

Assessing the Impact of Colchicine on Coronary Plaque Phenotype After Myocardial Infarction with Optical Coherence Tomography: Rationale and Design of the COCOMO-ACS Study

Introduction

Recurrent event rates after myocardial infarction (MI) remain unacceptably high, in part because of the continued growth and destabilization of residual coronary atherosclerotic plaques, which may occur despite lipid-lowering therapy. Inflammation is an important contributor to this ongoing risk. Recent studies have shown that the broad-acting anti-inflammatory agent, colchicine, may reduce adverse cardiovascular events in patients post-MI, although the mechanistic basis for this remains unclear. Advances in endovascular arterial wall imaging have allowed detailed characterization of the burden and compositional phenotype of coronary plaque, along with its natural history and responsiveness to treatment. One such example has been the use of optical coherence tomography (OCT) to demonstrate the plaque-stabilizing effects of statins on both fibrous cap thickness and the size of lipid pools within plaque.

Methods

The Phase 2, multi-centre, double-blind colchicine for coronary plaque modification in acute coronary syndrome (COCOMO-ACS) study will evaluate the effect of colchicine 0.5 mg daily on coronary plaque features using serial OCT imaging in patients following MI. Recruitment for the trial has been completed with 64 participants with non-ST elevation MI randomized 1:1 to colchicine or placebo in addition to guideline recommended therapies, including high-intensity statins. The primary endpoint is the effect of colchicine on the minimal fibrous cap thickness of non-culprit plaque over an 18-month period.

Summary

The COCOMO-ACS study will determine whether addition of colchicine 0.5 mg daily to standard post-MI treatment has incremental benefits on high-risk features of coronary artery plaques. If confirmed, this will provide new mechanistic insights into how colchicine may confer clinical benefits in patients with atherosclerotic cardiovascular disease.

Trial Registration

ANZCTR trial registration number: ACTRN12618000809235. Date of trial registration: 11th of May 2018.

Clinical Impact of Irregular Protrusion Angle After Coronary Stenting at Culprit Lesions With ST-Elevation Myocardial Infarction - An Intravascular Optical Coherence Tomography Study

Background: A recent optical coherence tomography (OCT) registry showed that the presence of irregular protrusion (IP) after coronary stenting was a predictor of worse 1-year cardiovascular events. This study evaluated the clinical impact of OCT-detected IP after coronary stenting at ST-elevation myocardial infarction (STEMI) culprit lesions. Methods and Results: In all, 139 consecutive STEMI patients with OCT-detected IP after stenting were analyzed retrospectively. The maximum IP angles were measured and patients with IP were divided into 2 groups (large IP, maximum IP angle ≥180°; small IP, 0°<angle<180°). The primary endpoints were cardiac death, target vessel myocardial infarction, target lesion revascularization, and stent thrombosis at 1 year after the index percutaneous coronary intervention (PCI). Of STEMI patients with IP, 51.8% had large IP. The incidence of the primary endpoints higher was higher in the large than small IP group (12.5% vs. 1.5%, respectively; P=0.018). The occurrence of plaque rupture was an independent predictor of large IP (odds ratio 4.58; 95% confidential interval 1.86-11.27; P=0.001). Conclusions: Maximum IP angle ≥180° was an independent predictor of clinical events in STEMI patients with IP.

Molecular Imaging and Non-molecular Imaging of Atherosclerotic Plaque Thrombosis

Thrombosis in the context of atherosclerosis typically results in life-threatening consequences, including acute coronary events and ischemic stroke. As such, early detection and treatment of thrombosis in atherosclerosis patients is essential. Clinical diagnosis of thrombosis in these patients is typically based upon a combination of imaging approaches. However, conventional imaging modalities primarily focus on assessing the anatomical structure and physiological function, severely constraining their ability to detect early thrombus formation or the processes underlying such pathology. Recently, however, novel molecular and non-molecular imaging strategies have been developed to assess thrombus composition and activity at the molecular and cellular levels more accurately. These approaches have been successfully used to markedly reduce rates of atherothrombotic events in patients suffering from acute coronary syndrome (ACS) by facilitating simultaneous diagnosis and personalized treatment of thrombosis. Moreover, these modalities allow monitoring of plaque condition for preventing plaque rupture and associated adverse cardiovascular events in such patients. Sustained developments in molecular and non-molecular imaging technologies have enabled the increasingly specific and sensitive diagnosis of atherothrombosis in animal studies and clinical settings, making these technologies invaluable to patients' health in the future. In the present review, we discuss current progress regarding the non-molecular and molecular imaging of thrombosis in different animal studies and atherosclerotic patients.

Is the effect of atorvastatin 60 mg on stabilization of lipid-rich plaque equivalent to that of rosuvastatin 10 mg? A serial optical coherence tomography combined with intravascular ultrasound imaging

OBJECTIVES

This study aimed to compare the effect of atorvastatin 60 (AT60) mg to that of rosuvastatin 10 (RT10) mg on the morphological changes in lipid-rich plaques (LRPs) and plaque volume, using serial optical coherence tomography (OCT) and intravascular ultrasound imaging (IVUS).

BACKGROUND

Intensive lipid lowering therapy by statin provides more clinical benefit compared to that of moderate lipid lowering therapy.

METHODS

Fifty patients who underwent OCT and IVUS at baseline, 6, and 12 months were grouped by statin therapy into the AT60 mg (n = 27) and RT10 mg (n = 23) groups. The relationships between absolute and percentage changes in biomarkers and fibrous cap thickness (FCT) during follow-up were investigated using a simple regression analysis.

RESULTS

At 6 months, the mean low-density lipoprotein cholesterol level reduced from 113.5 to 65.5 mg/dl (AT60 mg group) and 100.2 to 72.2 mg/dl (RT10 mg groups). A continuous increase in FCT from baseline to 12 months was observed in both groups (p < .001, p < .001, respectively). Mean lipid arc significantly decreased in both AT60 mg (189.0 ± 55.9°, 170.9 ± 60.2°, 155.6 ± 50.6°, p < .001) and RT10 mg (160.0 ± 45.6°, 151.2 ± 48.5°, 141.1 ± 52.9°, p = .010) groups. Plaque burden did not change significantly in both groups.

CONCLUSIONS

Lipid-lowering therapy effect with AT60 mg was equivalent to that of RT10 mg in terms of change in plaque morphology. AT60 mg showed more intensive low-density lipid cholesterol level reduction compared to RT10 mg while RT10 mg was effective in increasing the high-density lipid cholesterol level. Both statin therapies could effectively stabilize LRPs.

Multi-modality intravascular imaging for guiding coronary intervention and assessing coronary atheroma: the Novasight Hybrid IVUS-OCT system

Intravascular imaging has evolved alongside interventional cardiology as an adjunctive tool for assessing plaque pathology and for guiding and optimising percutaneous coronary intervention (PCI) in challenging lesions. The two modalities which have dominated the field are intravascular ultrasound (IVUS), which relies on sound waves and optical coherence tomography (OCT), relying on light waves. These approaches however have limited efficacy in assessing plaque morphology and vulnerability that are essential for guiding PCI in complex lesions and identifying patient at risk that will benefit from emerging therapies targeting plaque evolution. These limitations are complementary and, in this context, it has been recognised and demonstrated in multi-modality studies that the concurrent use of IVUS and OCT can help overcome these deficits enabling a more complete and accurate plaque assessment. The Conavi Novasight Hybrid IVUS-OCT catheter is the first commercially available device that is capable of invasive clinical coronary assessment with simultaneously acquired and co-registered IVUS and OCT imaging. It represents a significant evolution in the field and is expected to have broad application in clinical practice and research. In this review article we present the limitations of standalone intravascular imaging techniques, summarise the data supporting the value of multimodality imaging in clinical practice and research, describe the Novasight Hybrid IVUS-OCT system and highlight the potential utility of this technology in coronary intervention and in the study of atherosclerosis.

Assessing the impact of PCSK9 inhibition on coronary plaque phenotype with optical coherence tomography: rationale and design of the randomized, placebo-controlled HUYGENS study

Background

Technological advances in arterial wall imaging permit the opportunity to visualize coronary atherosclerotic plaque with sufficient resolution to characterize both its burden and compositional phenotype. These modalities have been used extensively in clinical trials to evaluate the impact of lipid lowering therapies on serial changes in disease burden. While the findings have unequivocally established that these interventions have the capacity to either slow disease progression or promote plaque regression, depending on the degree of lipid lowering achieved, their impact on plaque phenotype is less certain. More recently optical coherence tomography (OCT) has been employed with a number of studies demonstrating favorable effects on both fibrous cap thickness (FCT) and the size of lipid pools within plaque in response to statin treatment.

Methods

The phase 3, multi-center, double-blind HUYGENS study will assess the impact of incremental lipid lowering with the proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitor, evolocumab, on plaque features using serial OCT imaging, in statin-treated patients following an acute coronary syndrome (ACS). Subjects with non-ST-elevation ACS (n=150) will be randomized 1:1 into two groups to receive monthly injections of evolocumab 420 mg or placebo.

Results

The primary endpoint is the effect of evolocumab on coronary atherosclerotic plaques will be assessed by OCT at baseline and at week 50.

Conclusions

The HUYGENS study will determine whether intensified lipid lowering therapy with evolocumab in addition to maximally tolerated statin therapy will have incremental benefits on high-risk features of coronary artery plaques.

Trial registration

This study was registered on Clinicaltrials.gov (NCT03570697).

Coronary Artery Calcification Under Statin Therapy and Its Effect on Cardiovascular Outcomes: A Systematic Review and Meta-Analysis

Objective: To compare Agatston scores between patients without statin therapy and those under standard and intensive statin therapy and to systematically review the relationship between coronary artery calcification (CAC) progression under statin therapy and cardiovascular outcomes.

Methods: Literature search was conducted across databases. Randomized controlled trials and observational studies that reported Agatston scores at baseline and follow-up from patients with and without statin therapy were included. A systematic review and meta-analysis was conducted.

Results: Seven studies were subjected to qualitative and quantitative analyses. Agatston scores in all groups were increased at follow-up. Meta-analysis of data from the included studies revealed an insignificantly lower CAC score at follow-up in the experimental groups. Subgroup analysis showed that statins slowed down CAC progression mildly but with statistical significance in population with baseline CAC score >400 in the experimental groups (P = 0.009). Despite that calcification progressors had worse cardiovascular outcome than did non-progressors, it appeared that baseline CAC score had more decisive effects on cardiovascular outcomes. CAC progression under statin therapy did not increase cardiovascular risk, although more supportive data are needed.

Conclusion: Statins do not reduce or enhance CAC as measured by Agatston score in asymptomatic populations at high risk of cardiovascular diseases, but seem to slow down CAC progression. Although our result was robust, it was restricted by small sample size and relatively short follow-up period. Further studies on the relationship between CAC progression under statin therapy and cardiovascular outcomes are needed.

Using optical coherence tomography and intravascular ultrasound imaging to quantify coronary plaque cap thickness and vulnerability: a pilot study

Background

Detecting coronary vulnerable plaques in vivo and assessing their vulnerability have been great challenges for clinicians and the research community. Intravascular ultrasound (IVUS) is commonly used in clinical practice for diagnosis and treatment decisions. However, due to IVUS limited resolution (about 150–200 µm), it is not sufficient to detect vulnerable plaques with a threshold cap thickness of 65 µm. Optical Coherence Tomography (OCT) has a resolution of 15–20 µm and can measure fibrous cap thickness more accurately. The aim of this study was to use OCT as the benchmark to obtain patient-specific coronary plaque cap thickness and evaluate the differences between OCT and IVUS fibrous cap quantifications. A cap index with integer values 0–4 was also introduced as a quantitative measure of plaque vulnerability to study plaque vulnerability.

Methods

Data from 10 patients (mean age: 70.4; m: 6; f: 4) with coronary heart disease who underwent IVUS, OCT, and angiography were collected at Cardiovascular Research Foundation (CRF) using approved protocol with informed consent obtained. 348 slices with lipid core and fibrous caps were selected for study. Convolutional Neural Network (CNN)-based and expert-based data segmentation were performed using established methods previously published. Cap thickness data were extracted to quantify differences between IVUS and OCT measurements.

Results

For the 348 slices analyzed, the mean value difference between OCT and IVUS cap thickness measurements was 1.83% (p = 0.031). However, mean value of point-to-point differences was 35.76%. Comparing minimum cap thickness for each plaque, the mean value of the 20 plaque IVUS-OCT differences was 44.46%, ranging from 2.36% to 91.15%. For cap index values assigned to the 348 slices, the disagreement between OCT and IVUS assignments was 25%. However, for the OCT cap index = 2 and 3 groups, the disagreement rates were 91% and 80%, respectively. Furthermore, the observation of cap index changes from baseline to follow-up indicated that IVUS results differed from OCT by 80%.

Conclusions

These preliminary results demonstrated that there were significant differences between IVUS and OCT plaque cap thickness measurements. Large-scale patient studies are needed to confirm our findings.

Relation of Low-Density Lipoprotein Cholesterol Level to Plaque Rupture

Statin therapy reduces low-density lipoprotein cholesterol (LDL-C), inflammation, and atherosclerotic cardiovascular disease. We investigated the association between LDL-C and statin therapy on the prevalence of plaque rupture (PR). Patients with acute coronary syndromes who underwent optical coherence tomography imaging of the culprit lesion were divided into 4 groups based on LDL-C level and statin use (Group 1: LDL-C ≤ 100 without statin; Group 2; LDL-C ≤ 100 with statin; Group 3: LDL-C > 100 with statin; Group 4: LDL-C > 100 without statin), and the prevalence of PR was compared between the groups. Among 896 patients, PR was diagnosed in 444 (49.6%) patients. The prevalence of PR was significantly different among the 4 groups (p = 0.007): it was highest in the high LDL-C without statin group and lowest in the low LDL-C without statin group (53.9% and 39.2%, respectively). Compared with the high LDL-C without statin group, the low LDL-C without statin and low LDL-C with statin groups had a significantly lower prevalence of PR (p = 0.001, p = 0.040, respectively), and the low LDL-C with statin group had a significantly higher prevalence of calcification (p = 0.037). The patients with naturally low LDL-C have the lowest risk of PR. The patients with low LDL-C achieved by statin therapy had a higher prevalence of calcification. When LDL-C level is elevated, early and aggressive treatment with statin may help to prevent PR by stabilizing plaques through calcification.

Management of non-culprit coronary plaques in patients with acute coronary syndrome

Approximately 50% of patients with ST-segment elevation myocardial infarction (STEMI) have multivessel coronary artery disease, a condition associated with an increased incidence of recurrent ischaemic events and higher mortality. Based on recent evidences, a strategy of staged percutaneous coronary intervention (PCI) of obstructive non-culprit lesions should be considered the gold standard for the management of these patients. However, several issues remain still unresolved. Indeed, what is the optimal timing of staged PCI is not completely defined. Moreover, assessment of intermediate non-culprit lesions represent still a clinical conundrum, as pressure-wire indexes do not seem able to correctly identify those patients in whom deferral is safe. Intracoronary imaging may help to identify untreated non-culprit lesions containing vulnerable plaques that may portend a higher risk of future cardiovascular events. However, there are hitherto no studies demonstrating that preventive PCI of vulnerable plaques or more intensive pharmacological treatment is associated with an improved clinical outcome. In this review, we discuss the recent evolving concepts about management of non-culprit plaques in STEMI patients, proposing a diagnostic and therapeutic algorithm to guide physicians in clinical practice. We also underscore the several knowledge gaps to address in future studies.

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Latest Advances in Cardiac CT

Recent rapid technological advancements in cardiac CT have improved image quality and reduced radiation exposure to patients. Furthermore, key insights from large cohort trials have helped delineate cardiovascular disease risk as a function of overall coronary plaque burden and the morphological appearance of individual plaques. The advent of CT-derived fractional flow reserve promises to establish an anatomical and functional test within one modality. Recent data examining the short-term impact of CT-derived fractional flow reserve on downstream care and clinical outcomes have been published. In addition, machine learning is a concept that is being increasingly applied to diagnostic medicine. Over the coming decade, machine learning will begin to be integrated into cardiac CT, and will potentially make a tangible difference to how this modality evolves. The authors have performed an extensive literature review and comprehensive analysis of the recent advances in cardiac CT. They review how recent advances currently impact on clinical care and potential future directions for this imaging modality.

Effect of Statin Therapy on Fibrous Cap Thickness in Coronary Plaque on Optical Coherence Tomography - Review and Meta-Analysis

BACKGROUND

Statin therapy has been shown to result in coronary plaque regression, but the relationship between statin use and stabilization of coronary plaque has not been elucidated. We conducted a systematic review and meta-analysis to evaluate the effect of statin therapy on fibrous cap thickness (FCT) on optical coherence tomography (OCT).Methods and Results:Nine OCT studies (6 randomized controlled trials and 3 observational studies) were enrolled with a total of 341 patients (390 lesions). Arms of the studies were grouped according to statin type and/or dose. Random effects meta-analysis was used to estimate a pooled mean change in FCT from baseline to follow-up. The overall effect mean FCT change was 67.7 µm (95% CI: 51.4-84.1, I²=95.0%, P<0.001). All statin groups had an increase in FCT, but the magnitude of the increase differed according to the statin. Two homogeneous subgroups with I²=0 were identified: mean FCT change was 27.8 µm (for subgroup atorvastatin 5 mg and rosuvastatin), and 61.9 µm (for subgroup atorvastatin 20 mg, fluvastatin 30 mg, and pitavastatin 4 mg). On meta-regression modeling, statin therapy alone explained most of the change in FCT.

CONCLUSIONS

Statin therapy induced a significant increase in FCT as assessed on OCT, independent of coronary risk factors and other medications.

Comparison of Rosuvastatin Versus Atorvastatin for Coronary Plaque Stabilization

Statins are widely used to lower cholesterol and to reduce cardiovascular events. Whether all statins have similar effects on plaque stabilization is unknown. We aimed to investigate coronary plaque response to treatment with different statins that result in similar lipid reduction using serial multimodality intracoronary imaging. Patients with de novo coronary artery disease requiring intervention were randomized to rosuvastatin 10mg (R10) or atorvastatin 20mg (A20) daily. Optical coherence tomography and intravascular ultrasound were performed at baseline, 6 months, and 12 months. Untreated nonculprit plaques were analyzed by optical coherence tomography for thin-cap fibroatheroma, minimum fibrous cap thickness, lipid arc, and lipid length. Total and percent atheroma volume, respectively were analyzed by intravascular ultrasound. Forty-three patients completed the protocol (R10: 24 patients, 31 plaques; A20: 19 patients, 30 plaques). The decrease in serum lipids was similar. From baseline to 6 months to 12 months, minimum fibrous cap thickness increased in the R10 group (61.4 ± 15.9 µm to 120.9 ± 57.9 µm to 171.5 ± 67.8 µm, p <0.001) and the A20 group (60.8 ± 18.1 µm to 99.2 ± 47.7 µm to 127.0± 66.8 µm, p <0.001). Prevalence of thin-cap fibroatheroma significantly decreased in the R10 and A20 groups (-48% and -53%, respectively, p <0.001 for intragroup comparisons). Only the R10 group had a decrease in macrophage density (-23%, p = 0.04) and microvessels (-12%, p = 0.002). Total atheroma volume decreased in the R10 group (109.2 ± 62.1 mm³ to 101.8 ± 61.1 mm³ to 102.5 ± 62.2 mm³, p = 0.047) but not in the A20 group (83.3 ± 48.5mm³ to 77.6 ± 43.0 mm³ to 77.9 ± 48.6 mm³, p = 0.07). In conclusion, although both statins demonstrated similar reductions in lipid profiles, the rosuvastatin group showed more rapid and robust plaque stabilization, and regression of plaque volume compared to the atorvastatin group.

Comparison of Vascular Response to Statin Therapy in Patients With Versus Without Diabetes Mellitus

Diabetes mellitus (DM) increases cardiovascular morbidity and mortality. A statin is routinely prescribed to patients with DM. However, whether a statin therapy is equally effective in plaque stabilization in DM patients compared with non-DM patients is unknown. A total of 117 lipid-rich plaques were imaged in 90 patients (54 plaques in 41 DM patients and 63 plaques in 49 non-DM patients) with coronary artery disease, those who were treated with a statin and underwent serial optical coherence tomography imaging were included in this study (mean follow-up period, 362 ± 38 days). The changes in minimum fibrous cap thickness (FCT) and lipid index between baseline and 1-year follow-up were compared between the 2 groups. Minimum FCT increased and lipid index decreased with statin therapy in both groups. No significant differences were observed in percent changes of minimum FCT (p = 0.796) and lipid index (p = 0.336) between DM and non-DM patients. Statin therapy induced a significant increase in FCT and a significant decrease in lipid index in both groups. Vascular response to statin therapy was similar between the 2 groups irrespective of DM status.

Effects of statins on plaque rupture assessed by optical coherence tomography in patients presenting with acute coronary syndromes: insights from the optical coherence tomography (OCT)-FORMIDABLE registry

Aims

Chronic pre-treatment with statins may reduce mortality and morbidity in patients experiencing acute coronary syndromes (ACS), but mechanisms accounting for these findings are not completely understood.

Methods and results

The optical coherence tomography (OCT)-Formidable registry retrospectively enrolled 285 consecutive patients with ACS undergoing OCT in 9 European centres. Mean age was 60.4 ± 12.8 years, 148 (51.9%) patients had hyperlipemia, 45 (15.8%) diabetes mellitus and 142 (49.8%) presented with ST Segment Elevation Myocardial Infarction (STEMI). Patients were stratified according to statin prescription: 150 (52.6%) were on chronic pre-treatment with statins before ACS and were more likely to present with non-ST segment elevation acute coronary syndromes (NSTE-ACS) at admission (111, 74%) rather than STEMI, while the opposite was observed for patients not on statins. The primary end-point of ruptured plaque at OCT occurred significantly less frequently in the patients on chronic pre-treatment with statins [odds ratio (OR) 0.375, 95% confidence interval (CI) 0.185-0.759, P = 0.006]. The secondary end-point of thin-cap fibro-atheroma (TCFA) at any site was significantly less frequent in the statin group (OR 0.423, 95%CI 0.213-0.840, P = 0.014). No differences were observed for the secondary end-point of not-ruptured TCFA as the culprit lesion. Pre-specified sensitivity analysis was conducted according to the pattern of ACS: the reported differences were confirmed for NSTE-ACS patients, with a trend towards less plaque rupture and a significant reduction of TCFA at any site with statins, but not for STEMI.

Conclusions

Chronic pre-treatment with statins is associated with a reduced prevalence of ruptured plaques in patients presenting with ACS, particularly in those with NSTE-ACS. Statins bear hence the potential to reduce morbidity during the acute phase of ACS.

Optimized Computer-Aided Segmentation and Three-Dimensional Reconstruction Using Intracoronary Optical Coherence Tomography

We present a novel and time-efficient method for intracoronary lumen detection, which produces three-dimensional (3-D) coronary arteries using optical coherence tomographic (OCT) images. OCT images are acquired for multiple patients and longitudinal cross-section (LOCS) images are reconstructed using different acquisition angles. The lumen contours for each LOCS image are extracted and translated to 2-D cross-sectional images. Using two angiographic projections, the centerline of the coronary vessel is reconstructed in 3-D, and the detected 2-D contours are transformed to 3-D and placed perpendicular to the centerline. To validate the proposed method, 613 manual annotations from medical experts were used as gold standard. The 2-D detected contours were compared with the annotated contours, and the 3-D reconstructed models produced using the detected contours were compared to the models produced by the annotated contours. Wall shear stress (WSS), as dominant hemodynamics factor, was calculated using computational fluid dynamics and 844 consecutive 2-mm segments of the 3-D models were extracted and compared with each other. High Pearson's correlation coefficients were obtained for the lumen area (r = 0.98) and local WSS (r = 0.97) measurements, while no significant bias with good limits of agreement was shown in the Bland-Altman analysis. The overlapping and nonoverlapping areas ratio between experts' annotations and presented method was 0.92 and 0.14, respectively. The proposed computer-aided lumen extraction and 3-D vessel reconstruction method is fast, accurate, and likely to assist in a number of research and clinical applications.

Pre-existing treatment with aspirin or statins influences clinical presentation, infarct size and inflammation in patients with de novo acute coronary syndromes

BACKGROUND

Influence of pre-existing treatment with aspirin and/or statins prior to a first acute coronary syndrome (ACS) on clinical presentation, infarct size and inflammation markers. We analyzed patients from the Swiss Program University Medicine ACS-cohort (SPUM-ACS; ClinicalTrials.govnumber:NCT01075867).

METHODS

1639 patients were categorized into 4 groups: (1) patients without either drug (n = 1181); (2) patients only on aspirin (n = 157); (3) patients only on statins (n = 133) and (4) patients on both drugs (n = 168). Clinical features, electrocardiogram (ECG), creatinine kinase (CK, U/l), high-sensitivity troponin T (hsTNT, μg/l), N-terminal brain natriuretic peptide (NT-proBNP, ng/l), leucocytes (Lc, G/l), neutrophils (Nc, G/l), C-reactive protein (CRP, mg/l) and angiographic features were documented at baseline.

RESULTS

Incidences of ST-elevation myocardial infarction (STEMI) were 64% in group 1, 45% in group 2, 52% in group 3 and 40% in group 4 (p < 0.0001). Those with both drugs had significantly lower CK (median 145 U/l, interquartile range (IQR) 89-297), hsTNT (median 0.13 μg/l, IQR 0.03-0.52) and higher left ventricular ejection fraction values (LVEF) (mean 55 ± 12%) compared to untreated patients (median CK 273 U/l, IQR 128-638; median hsTNT 0.26 μg/l, IQR 0.08-0.85; mean LVEF 51 ± 11%) (p < 0.0001, p = 0.001, p = 0.028, respectively). Co-medicated groups matched for high risk factors presented less frequently as STEMIs (p < 0.0001), had significantly smaller infarcts determined by CK and hsTNT (both p < 0.0001) and lower CRP levels (p = 0.01) compared to patients without pre-existing treatment with either drug.

CONCLUSION

Pre-existing treatment with aspirin and/or statins and particularly with their combination changes the clinical presentation, infarct size, inflammation markers and LVEF in patients suffering their first ACS.

Is age an important factor for vascular response to statin therapy? A serial optical coherence tomography and intravascular ultrasound study

OBJECTIVE

Age-related structural and functional changes in vessel wall may affect the time course of vascular response to statin therapy. In this study, we sought to compare the response of lipid-rich plaque to statin therapy in elderly versus younger patients using optical coherence tomography and intravascular ultrasound.

PATIENTS AND METHODS

Sixty-nine patients who underwent serial optical coherence tomography and intravascular ultrasound at the time point of baseline, 6, and 12 months were divided into two groups according to median age: group A (age<57 years, n=35) and group B (age≥57 years, n=34). Patients were treated with intensive (atorvastatin 60 mg/day) or moderate (atorvastatin 20 mg/day or rosuvastatin 10 mg/day) statin therapy.

RESULTS

A continuous increase in fibrous-cap thickness (FCT) from baseline to 12 months was observed in both groups (P<0.001, <0.001, respectively). Intensive statin induced greater percent change in FCT at 12 months than moderate statin in group B (P=0.020), but not in group A (P=0.251). Mean lipid arc decreased significantly at 12 months in two groups (P<0.001, <0.001, respectively), and this response was delayed for 6 months (P=0.403) and began to decrease during the second 6 months (P<0.001) in group B. Normalized total atheroma volume decreased significantly in group A (P<0.001), but not in group B (P=0.349).

CONCLUSION

Statin therapy could stabilize lipid-rich plaque irrespective of age, and intensive statin therapy was more effective than a moderate dose of statin in increasing FCT, particularly in older patients. A delayed response of lipid content and unfavorable change in normalized total atheroma volume to statin were observed in elderly patients.

Clinical Predictors for Lack of Favorable Vascular Response to Statin Therapy in Patients With Coronary Artery Disease: A Serial Optical Coherence Tomography Study

Background

Previous studies have demonstrated that statin therapy improves cardiac outcomes, probably by stabilizing thin‐cap fibroatheroma in patients with coronary artery disease. However, major adverse cardiac events still occur in some patients, despite statin therapy. The aim of this study is to identify clinical predictors for the lack of a favorable vascular response to statin therapy in patients with coronary artery disease.

Methods and Results

A total of 140 nonculprit plaques from 84 patients with coronary artery disease who were treated with a statin and had serial optical coherence tomography imaging (median interval, 6.3 months) were included. Thin‐cap area (fibrous cap thickness, <200 μm) was measured using a novel 3‐dimensional computer‐aided algorithm. Overall, the thin‐cap area significantly decreased from baseline (median, 2.852 mm²; 25^th–75^th percentile, 1.023–6.157 mm²) to follow‐up (median, 1.210 mm²; 25^th–75^th percentile, 0.250–3.192 mm²; P<0.001), and low‐density lipoprotein cholesterol significantly decreased from baseline (mean±SD, 92.9±30.1 mg/dL) to follow‐up (mean±SD, 76.3±23.3 mg/dL; P<0.001). The general linear model with multiple predictor variables revealed that the thin‐cap area was significantly higher in patients with chronic kidney disease than in those without it (regression coefficient b, 1.691 mm²; 95% confidence interval, 0.350–3.033 mm²; P=0.013) and lower in patients with acute coronary syndrome (regression coefficient b, −1.535 mm²; 95% confidence interval, −2.561 to −0.509 mm²; P=0.003).

Conclusions

Chronic kidney disease is an independent predictor for the lack of a favorable vascular response to statin therapy, whereas acute coronary syndrome is an independent predictor for favorable vascular response to statin therapy. These findings should be further warranted in future prospective studies.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01110538.

Lower Level of Low Density Lipoprotein Cholesterol is Associated with a Higher Increase in the Fractional Flow Reserve in Patients with Fixed-dose Rosuvastatin

Aim: Fractional flow reserve (FFR) reflects on the diffuse atherosclerosis per coronary artery. It is unknown whether the statin therapy affects long term FFR after stenting. The aim of this study was to evaluate the long term FFR after stent implantation in patients who are intaking fixed-dose rosuvastatin.

Methods: A total of 22 patients with stable angina pectoris were enrolled. The values of FFR were measured before, immediately after, and 18 months after (follow-up day) the implantation of everolimus eluting stent (EES; Promus Element™ or Promus Element Plus™). A fixed dose of rosuvastatin at 5 mg/day was administrated to all patients.

Results: Of the 22 patients, 2 were excluded because of adverse effect of rosuvastatin and in-stent total occlusion after EES implantation. Overall, the values of FFR immediately after and 18 months after EES implantation did not show significant change (from 0.90 ± 0.05 to 0.88 ± 0.06, p = 0.16). However, there was a significant negative correlation between low density lipoprotein (LDL) cholesterol level at follow-up day and changes in the value of FFR (p = 0.01, r = −0.74). There was an increase in the FFR value after stenting in 8 out of 9 patients with LDL cholesterol level below 75 mg/dl (area under the curve 0.92, p = 0.0005).

Conclusions: LDL cholesterol level was associated with the change in the FFR value in patients following stent implantation. Lower LDL cholesterol tended to improve in the long-term FFR, underscoring the importance of lowering LDL cholesterol to prevent the progression of coronary atherosclerosis.

Intravascular imaging in cardiovascular ageing

Ageing is related to complex molecular, inflammatory and biochemical changes that affect coronary pathology and often lead to coronary artery disease and cardiovascular events. Intravascular imaging is considered as the ideal technique to study coronary plaque morphology and assess its burden. Over the recent years several studies have been performed that investigated the association between pathophysiological mechanisms that promote vascular ageing and plaque morphology. In addition, several reports have compared plaque pathology in different age groups and a few studies included serial intravascular imaging to assess changes in the atheroma burden and compositional characteristics of the plaque. This review article summarizes the evidence derived from intravascular imaging studies about the implications of vascular ageing on coronary artery morphology and discusses the potential of coronary imaging in assessing atherosclerotic evolution.

Lipid Lowering Therapy to Modify Plaque Microstructures

Due to the pandemics of obesity and diabetes mellitus, especially in the Western countries, atherosclerotic cardiovascular disease (ASCVD) has become a major health burden and is expected to increase in the future. Modifying lipid targets, especially low-density lipoprotein cholesterol (LDL-C) level, has become the first-line therapy for primary and secondary prevention of ASCVD. Intravascular imaging modalities have contributed to elucidating clinical efficacy of lipid lowering therapy on atherosclerotic plaques. Optical coherence tomography (OCT) is a high-resolution imaging tool enables visualization of plaque microstructures associated with its instability. This modality has demonstrated favorable changes in plaque microstructures under lowering LDL-C level. In addition, clinical studies using OCT have suggested potential association of other lipid targets, including triglyceride and high-density lipoprotein cholesterol with plaque microstructures. Given continuing cardiovascular risks despite statin therapy, OCT will be an important imaging modality to evaluate novel therapeutic approaches that potentially modulates plaque instability.