Relationship between coronary plaque morphology of the left anterior descending artery and 12 months clinical outcome: the CLIMA study

Preventive percutaneous coronary intervention versus optimal medical therapy alone for the treatment of vulnerable atherosclerotic coronary plaques (PREVENT): a multicentre, open-label, randomised controlled trial

BACKGROUND

Acute coronary syndrome and sudden cardiac death are often caused by rupture and thrombosis of lipid-rich atherosclerotic coronary plaques (known as vulnerable plaques), many of which are non-flow-limiting. The safety and effectiveness of focal preventive therapy with percutaneous coronary intervention of vulnerable plaques in reducing adverse cardiac events are unknown. We aimed to assess whether preventive percutaneous coronary intervention of non-flow-limiting vulnerable plaques improves clinical outcomes compared with optimal medical therapy alone.

METHODS

PREVENT was a multicentre, open-label, randomised controlled trial done at 15 research hospitals in four countries (South Korea, Japan, Taiwan, and New Zealand). Patients aged 18 years or older with non-flow-limiting (fractional flow reserve >0·80) vulnerable coronary plaques identified by intracoronary imaging were randomly assigned (1:1) to either percutaneous coronary intervention plus optimal medical therapy or optimal medical therapy alone, in block sizes of 4 or 6, stratified by diabetes status and the performance of percutaneous coronary intervention in a non-study target vessel. Follow-up continued annually in all enrolled patients until the last enrolled patient reached 2 years after randomisation. The primary outcome was a composite of death from cardiac causes, target-vessel myocardial infarction, ischaemia-driven target-vessel revascularisation, or hospitalisation for unstable or progressive angina, assessed in the intention-to-treat population at 2 years. Time-to-first-event estimates were calculated with the Kaplan-Meier method and were compared with the log-rank test. This report is the principal analysis from the trial and includes all long-term analysed data. The trial is registered at ClinicalTrials.gov, NCT02316886, and is complete.

FINDINGS

Between Sept 23, 2015, and Sept 29, 2021, 5627 patients were screened for eligibility, 1606 of whom were enrolled and randomly assigned to percutaneous coronary intervention (n=803) or optimal medical therapy alone (n=803). 1177 (73%) patients were men and 429 (27%) were women. 2-year follow-up for the primary outcome assessment was completed in 1556 (97%) patients (percutaneous coronary intervention group n=780; optimal medical therapy group n=776). At 2 years, the primary outcome occurred in three (0·4%) patients in the percutaneous coronary intervention group and in 27 (3·4%) patients in the medical therapy group (absolute difference -3·0 percentage points [95% CI -4·4 to -1·8]; p=0·0003). The effect of preventive percutaneous coronary intervention was directionally consistent for each component of the primary composite outcome. Serious clinical or adverse events did not differ between the percutaneous coronary intervention group and the medical therapy group: at 2 years, four (0·5%) versus ten (1·3%) patients died (absolute difference -0·8 percentage points [95% CI -1·7 to 0·2]) and nine (1·1%) versus 13 (1·7%) patients had myocardial infarction (absolute difference -0·5 percentage points [-1·7 to 0·6]).

INTERPRETATION

In patients with non-flow-limiting vulnerable coronary plaques, preventive percutaneous coronary intervention reduced major adverse cardiac events arising from high-risk vulnerable plaques, compared with optimal medical therapy alone. Given that PREVENT is the first large trial to show the potential effect of the focal treatment for vulnerable plaques, these findings support consideration to expand indications for percutaneous coronary intervention to include non-flow-limiting, high-risk vulnerable plaques.

FUNDING

The CardioVascular Research Foundation, Abbott, Yuhan Corp, CAH-Cordis, Philips, and Infraredx, a Nipro company.

Automatic assessment of atherosclerotic plaque features by intracoronary imaging: a scoping review

Background

The diagnostic performance and clinical validity of automatic intracoronary imaging (ICI) tools for atherosclerotic plaque assessment have not been systematically investigated so far.

Methods

We performed a scoping review including studies on automatic tools for automatic plaque components assessment by means of optical coherence tomography (OCT) or intravascular imaging (IVUS). We summarized study characteristics and reported the specifics and diagnostic performance of developed tools.

Results

Overall, 42 OCT and 26 IVUS studies fulfilling the eligibility criteria were found, with the majority published in the last 5 years (86% of the OCT and 73% of the IVUS studies). A convolutional neural network deep-learning method was applied in 71% of OCT- and 34% of IVUS-studies. Calcium was the most frequent plaque feature analyzed (26/42 of OCT and 12/26 of IVUS studies), and both modalities showed high discriminatory performance in testing sets [range of area under the curve (AUC): 0.91-0.99 for OCT and 0.89-0.98 for IVUS]. Lipid component was investigated only in OCT studies (n = 26, AUC: 0.82-0.86). Fibrous cap thickness or thin-cap fibroatheroma were mainly investigated in OCT studies (n = 8, AUC: 0.82-0.94). Plaque burden was mainly assessed in IVUS studies (n = 15, testing set AUC reported in one study: 0.70).

Conclusion

A limited number of automatic machine learning-derived tools for ICI analysis is currently available. The majority have been developed for calcium detection for either OCT or IVUS images. The reporting of the development and validation process of automated intracoronary imaging analyses is heterogeneous and lacks critical information.

Systematic Review Registration

Open Science Framework (OSF), https://osf.io/nps2b/.Graphical AbstractCentral Illustration.

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.

Pancoronary plaque characteristics in STEMI patients with rapid plaque progression: An optical coherence tomography study

BACKGROUND

Non-culprit plaque progression is associated with recurrent cardiac ischemic events and worse clinical outcomes. Given that atherosclerosis is a systemic disease, the pancoronary characteristics of patients with rapid plaque progression are unknown. This study aims to identify pancoronary plaque features in patients with ST-segment elevation myocardial infarction (STEMI) with and without rapid plaque progression, focused on the patient level.

METHODS AND RESULTS

From January 2017 to July 2019, 291 patients underwent 3-vessel optical coherence tomography imaging at the time of the primary procedure and a follow-up angiography interval of 12 months. The final analysis included 237 patients. Overall, 308 non-culprit lesions were found in 78 STEMI patients with rapid plaque progression, and 465 non-culprit plaques were found in 159 STEMI patients without rapid plaque progression. These patients had a higher pancoronary vulnerability (CLIMA-defined high-risk plaque: 47.4% vs. 33.3%; non-culprit plaque rupture: 25.6% vs. 14.5%) and a significantly higher prevalence of other vulnerable plaque characteristics (i.e., lipid-rich plaque, cholesterol crystal, microchannels, calcification, spotty calcification, and thrombus) at baseline versus those without rapid plaque progression. Lesions with rapid progression were highly distributed at the LAD, tending to be near the bifurcation. In multivariate analysis, age ≥ 65 years was an independent predictor of subsequent rapid lesion progression at the patient level, whereas microchannel, spotty calcification, and cholesterol crystal were independent predictors for STEMI patients ≥65 years old.

CONCLUSIONS

STEMI patients with subsequent rapid plaque progression had higher pancoronary vulnerability and commonly presented vulnerable plaque morphology. Aging was the only predictor of subsequent rapid plaque progression.

The accuracy of detailed analysis of optical coherence tomography in detection of plaque lipid content: dual-imaging study with optical coherence tomography and near-infrared spectroscopy

BACKGROUND

Lipid-rich plaque covered by a thin fibrous cap (FC) has been identified as a frequent morphological substrate for the development of acute coronary syndrome. Optical coherence tomography (OCT) permits the identification and measurement of the FC. Near-infrared spectroscopy (NIRS) has been approved for detection of coronary lipids.

AIMS

We aimed to assess the ability of detailed OCT analysis to identify coronary lipids, using NIRS as the reference method.

METHODS

In total, 40 patients with acute coronary syndrome underwent imaging of a non-culprit lesion by both NIRS and OCT. For each segment, the NIRS-derived 4 mm segment with maximal lipid core burden index (maxLCBI4mm) was assessed. OCT analysis was performed using a semi-automated method including measurement of the fibrous cap thickness (FCT) of all detected fibroatheromas. Subsequent quantitative volumetric evaluation furnished FCT, FC surface area (FC SA), lipid arc, and FC (fibrous cap) volume data. OCT features of lipid plaques were compared with maxLCBI4mm. Predictors of maxLCBI4mm >400 was assessed by using univariable and multivariable analysis.

RESULTS

OCT features (mean FCT, total FC SA, FC volume, maximal, mean, and total lipid arcs) strongly correlated with the maxLCBI4mm (p = 0.012 for the mean FCT, respectively p < 0.001 for all other aforementioned features). The strongest predictors of maxLCBI4mm >400 were the maximal (p = 0.002) and mean (p = 0.002) lipid arc, and total FC SA (p = 0.012).

CONCLUSIONS

We found a strong correlation between the OCT-derived features and NIRS findings. Detailed OCT analysis may be reliably used for detection of the presence of coronary lipids.

Comparison among various physiology and angiography-guided strategies for deferring percutaneous coronary intervention: A network meta-analysis

BACKGROUND/PURPOSE

It is unclear whether coronary physiology or coronary angiography (CA)-guided strategy is the more preferable approach for deferring percutaneous coronary intervention (PCI). We sought to evaluate the clinical efficacy of various PCI strategies through a network meta-analysis of randomized controlled trials (RCTs).

METHODS/MATERIALS

We searched multiple databases for RCTs investigating the impact of the following strategies for the purpose of determining whether or not to defer PCI: fractional flow reserve, instantaneous wave-free ratio, quantitative flow ratio (QFR), and CA. We conducted a network meta-analysis for trial-defined major adverse cardiovascular events (MACE), all-cause death, cardiovascular death, myocardial infarction (MI), target lesion revascularization (TLR), and stent thrombosis. We performed a subgroup analysis for those with acute coronary syndrome (ACS).

RESULTS

Our search identified 12 eligible RCTs including a total of 13,177 patients. QFR-guided PCI was associated with reduced MACE, MI, and TLR compared with CA-guided PCI (relative risk (RR) 0.68; 95 % confidence interval (CI] [0.49 to 0.94], RR 0.58; 95 % CI [0.36 to 0.96], and RR 0.58; 95 % CI [0.38 to 0.91], respectively). There were no significant differences in any pairs for all-cause death, cardiovascular death, or stent thrombosis. QFR was ranked the best in most outcomes. In the subgroup analysis of the ACS cohort, there were no significant differences in MACE between any comparisons.

CONCLUSIONS

QFR was associated with reduced MACE, MI, and TLR compared with CA, and ranked the best in most outcomes. However, this was not applied in the ACS cohort.

Intracoronary imaging to guide percutaneous coronary intervention: from evidence to guidelines

Despite notable advances in devices and techniques, percutaneous coronary intervention (PCI) is still affected by a substantial number of complications and failure rates. Over the years, the use of intracoronary imaging (ICI) has dramatically improved the understanding of mechanical and technical factors related to successful and failed PCI, becoming a mainstay in complex trans-catheter interventions. However, ICI modalities are invasive, time-consuming, and costly, and a net clinical benefit needs to be shown in order to recommend their routine use in clinical practice. In the past, the lack of evidence from randomized trials has been reflected in the scepticism shown by international guidelines. The recent publication of large randomized clinical trials conducted worldwide has provided new evidence regarding the clinical usefulness of ICI guidance in PCI. The consistent reduction of adverse events achieved in these trials, also demonstrated in an updated meta-analysis, suggested that the use of ICI in PCI is compelling to achieve optimal technical results and better outcomes, especially in complex high-risk interventions. Also considering the burden of information provided by ICI on coronary artery disease, looking from the inside seems today an opportunity that modern cardiology cannot ignore anymore.

Cholesterol crystals at the culprit lesion in patients with acute coronary syndrome are associated with worse cardiovascular outcomes at two years follow up - results from the translational OPTICO-ACS study program

BACKGROUND

Cholesterol crystals (CCs) represent a feature of advanced atherosclerotic plaque and may be assessed by optical coherence tomography (OCT). Their impact on cardiovascular outcomes in patients presenting with acute coronary syndromes (ACS) is yet unknown.

METHODS

The culprit lesion (CL) of 346 ACS-patients undergoing preintervention OCT imaging were screened for the presence of CCs and divided into two groups accordingly. The primary end-point was the rate of major adverse cardiac events plus (MACE+) consisting of cardiac death, myocardial infarction, target vessel revascularization and re-hospitalization due to unstable or progressive angina at two years.

RESULTS

Among 346 patients, 57.2% presented with CCs at the CL. Patients with CCs exhibited a higher prevalence of ruptured fibrous caps (RFC-ACS) (79.8% vs. 56.8%; p < 0.001) and other high-risk features such as thin cap fibroatheroma (80.8% vs. 64.9%; p = 0.001), presence of macrophages (99.0% vs. 85.1%; p < 0.001) as well as a greater maximum lipid arc (294.0° vs. 259.3°; p < 0.001) at the CL as compared to patients without CCs. MACE+ at two years follow-up occurred more often in CC-patients (29.2% vs. 16.1%; p = 0.006) as compared to patients without CCs at the culprit site. Multivariable cox regression analysis identified CCs as independent predictor of MACE+ (HR 1.705; 1.025-2.838 CI, p = 0.040).

CONCLUSIONS

CCs were associated with conventional high-risk plaque features and associated with increased MACE+-rates at two years follow up. The identification of CCs might be useful as prognostic marker in patients with ACS and assist "precision prevention" in the future.

In-hospital initiation of a PCSK9 inhibitor in patients with acute coronary syndrome: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have been shown to be effective and safe in patients with stable angina and previous myocardial infarction. However, evidence for initiating their use in patients hospitalized with acute coronary syndrome (ACS) is limited. This systematic review and meta-analysis was performed to provide more clinical evidence.

METHODS

PubMed, Embase, OVID, Cochrane Library and ClinicalTrials.gov were systematically searched for eligible randomized controlled trials up to March 20, 2023. The risk ratios, standardized mean differences and 95% confidence intervals were calculated for primary and secondary outcomes. The bias risk of the included studies was assessed using the Cochrane RoB 2 criteria.

RESULTS

About 8 randomized controlled trials involving 1255 inpatients with ACS were included. PCSK9 inhibitor treatment significantly reduced low-density lipoprotein cholesterol (LDL-C) (SMD -1.28, 95% CI -1.76 to -0.8, P = .001), triglycerides (TG) (SMD -0.93, 95% CI -1.82 to -0.05, P = .03), total cholesterol (SMD -1.36, 95% CI -2.01 to -0.71, P = .001), and apolipoprotein B (Apo B) (SMD -0.81, 95% CI -1.09 to -0.52, P = .001) within approximately 1 month. PCSK9 inhibitor treatment significantly reduced the total atheroma volume (TAV) (SMD -0.33, 95% CI -0.59 to -0.07, P = .012). It also significantly increased minimum fibrous cap thickness (FCT) (SMD 0.41, 95% CI 0.22-0.59, P = .001) in long-term follow-up (>6 months). PCSK9 inhibitor treatment significantly reduced the risk of readmission for unstable angina (RR 0.32, 95% CI 0.12-0.91, P = .032) in short-term follow-up (<6 months). There were no significant differences in all-cause mortality, cardiovascular death, myocardial infarction, ischemic stroke, coronary revascularization or heart failure. Only nasopharyngitis (RR 1.71, 95% CI 1.01-2.91, P = .047) adverse events were significantly observed in the PCSK9 inhibitor group.

CONCLUSION

Application of a PCSK9 inhibitor in hospitalized patients with ACS reduced lipid profiles and plaque burdens and was well tolerated with few adverse events.

Development of physiologically-informed computational coronary artery plaques for use in virtual imaging trials

BACKGROUND

As a leading cause of death, worldwide, cardiovascular disease is of great clinical importance. Among cardiovascular diseases, coronary artery disease (CAD) is a key contributor, and it is the attributed cause of death for 10% of all deaths annually. The prevalence of CAD is commensurate with the rise in new medical imaging technologies intended to aid in its diagnosis and treatment. The necessary clinical trials required to validate and optimize these technologies require a large cohort of carefully controlled patients, considerable time to complete, and can be prohibitively expensive. A safer, faster, less expensive alternative is using virtual imaging trials (VITs), utilizing virtual patients or phantoms combined with accurate computer models of imaging devices.

PURPOSE

In this work, we develop realistic, physiologically-informed models for coronary plaques for application in cardiac imaging VITs.

METHODS

Histology images of plaques at micron-level resolution were used to train a deep convolutional generative adversarial network (DC-GAN) to create a library of anatomically variable plaque models with clinical anatomical realism. The stability of each plaque was evaluated by finite element analysis (FEA) in which plaque components and vessels were meshed as volumes, modeled as specialized tissues, and subjected to the range of normal coronary blood pressures. To demonstrate the utility of the plaque models, we combined them with the whole-body XCAT computational phantom to perform initial simulations comparing standard energy-integrating detector (EID) CT with photon-counting detector (PCD) CT.

RESULTS

Our results show the network is capable of generating realistic, anatomically variable plaques. Our simulation results provide an initial demonstration of the utility of the generated plaque models as targets to compare different imaging devices.

CONCLUSIONS

Vast, realistic, and variable CAD pathologies can be generated to incorporate into computational phantoms for VITs. There they can serve as a known truth from which to optimize and evaluate cardiac imaging technologies quantitatively.

Comprehensive biomechanical and anatomical atherosclerotic plaque metrics predict major adverse cardiovascular events: A new tool for clinical decision making

BACKGROUND AND AIMS

Anatomical imaging alone of coronary atherosclerotic plaques is insufficient to identify risk of future adverse events and guide management of non-culprit lesions. Low endothelial shear stress (ESS) and high plaque structural stress (PSS) are associated with events, but individually their predictive value is insufficient for risk prediction. We determined whether combining multiple complementary, biomechanical and anatomical plaque characteristics improves outcome prediction sufficiently to inform clinical decision-making.

METHODS

We examined baseline ESS, ESS gradient (ESSG), PSS, and PSS heterogeneity index (HI), and plaque burden in 22 lesions that developed subsequent events and 64 control lesions that remained quiescent from the PROSPECT study.

RESULTS

86 fibroatheromas were analysed from 67 patients. Lesions with events showed higher PSS HI (0.32 vs. 0.24, p<0.001), lower local ESS (0.56Pa vs. 0.91Pa, p = 0.007), and higher ESSG (3.82 Pa/mm vs. 1.96 Pa/mm, p = 0.007), while high PSS HI (hazard ratio [HR] 3.9, p = 0.006), high ESSG (HR 3.4, p = 0.007) and plaque burden>70 % (HR 2.6, p = 0.02) were independent outcome predictors in multivariate analysis. Combining low ESS, high ESSG, and high PSS HI gave both high positive predictive value (80 %), which increased further combined with plaque burden>70 %, and negative predictive value (81.6 %). Low ESS, high ESSG, and high PSS HI co-localised spatially within 1 mm in lesions with events, and importantly, this cluster was distant from the minimum lumen area site.

CONCLUSIONS

Combining complementary biomechanical and anatomical metrics significantly improves risk-stratification of individual coronary lesions. If confirmed from larger prospective studies, our results may inform targeted revascularisation vs. conservative management strategies.

No evidence of coronary plaque stabilization by allopurinol in patients with acute coronary syndrome

BACKGROUND

Allopurinol, a xanthine inhibitor that lowers uric acid concentration, has been proven to reduce inflammation and oxidative stress in patients with cardiovascular disease. However, it is unknown whether these beneficial effects translate into favorable plaque modification in acute coronary syndromes (ACS). This study aimed to investigate whether allopurinol could improve coronary plaque stabilization using coronary computed tomography angiography (CCTA).

METHODS

This was a prospective, single-center, randomized, double-blind clinical trial began in March 2019. A total of 162 ACS patients aged 18-80 years with a blood level of high-sensitivity C-reactive protein (hsCRP) ​> ​2 ​mg/L were included. The subjects were randomly assigned in a 1:1 ratio to receive either allopurinol sustained-release capsules (at a dose of 0.25 ​g once daily) or placebo for 12 months. The plaque analysis was performed at CCTA. The primary efficacy endpoint was the change in low-attenuation plaque volume (LAPV) from baseline to the 12-month follow-up.

RESULTS

Among 162 patients, 54 in allopurinol group and 51 in placebo group completed the study. The median follow-up duration was 14 months in both groups. Compared with placebo, allopurinol therapy did not significantly alter LAPV (-13.4 ​± ​3.7 ​% vs. -17.8 ​± ​3.6 ​%, p ​= ​0.390), intermediate attenuation plaque volume (-16.1 ​± ​3.0 ​% vs. -16.2 ​± ​2.9 ​%, p ​= ​0.992), dense calcified plaque volume (12.2 ​± ​13.7 ​% vs. 9.7 ​± ​13.0 ​%, p ​= ​0.894), total atheroma volume (-15.2 ​± ​3.2 ​% vs. -16.4 ​± ​3.1 ​%, p ​= ​0.785), remodeling index (2.0 ​± ​3.9 ​% vs. 5.4 ​± ​3.8 ​%, p ​= ​0.536) or hsCRP levels (-73.6 [-91.6-17.9] % vs. -81.2 [-95.4-47.7] %, p ​= ​0.286).

CONCLUSIONS

Our findings suggest that allopurinol does not improve atherosclerotic plaque stability or inflammation in ACS.

Morphological characteristics of in-stent restenosis with different degrees of area stenosis: an optical coherence tomography study

The morphological characteristics of in-stent restenosis (ISR) in relation to varying degrees of area stenosis have not been comprehensively examined. This study aimed to explore the tissue characteristics of patients experiencing ISR with different degrees of area stenosis through the utilization of optical coherence tomography (OCT). In total, 230 patients with ISR who underwent OCT were divided into the following three groups: area stenosis (AS) < 70% (n = 26); 70-80% (n = 119) and AS ≥ 80% (n = 85). Among the 230 patients, the clinical presentation as stable angina was 61.5% in AS < 70%, followed by 47.2% in 70% < AS ≤ 80%, and 31.8% in AS ≥ 80% (P = 0.010). The OCT findings showed that heterogeneous neointima, ISNA, LRP, neointima rupture, TCFA-like pattern, macrophage infiltration, red and white thrombus was more common with AS increased. Ordinal logistic regression analysis showed that higher AS was associated with previous dyslipidemia (odds ratio [OR], 4.754; 95% confidence interval [CI], 1.419-15.927, P = 0.011), neointimal rupture (OR: 3.640; 95% CI, 1.169-11.325, P = 0.026), red thrombus (OR: 4.482; 95% CI, 1.269-15.816, P = 0.020) and white thrombus (OR: 5.259; 95% CI, 1.660-16.659, P = 0.005). Patients with higher degrees of area stenosis in the context of ISR exhibited a greater number of discernible morphological characteristics as identified through OCT analysis. Furthermore, previous dyslipidemia, neointimal rupture, white thrombus and red thrombus were highly associated with and the progression of ISR lesions.

Intravascular Imaging-Derived Physiology-Basic Principles and Clinical Application

Intravascular imaging-derived physiology is emerging as a promising tool allowing simultaneous anatomic and functional lesion assessment. Recently, several optical coherence tomography-based and intravascular ultrasound-based fractional flow reserve (FFR) indices have been developed that compute FFR through computational fluid dynamics, fluid dynamics equations, or machine-learning methods. This review aims to provide an overview of the currently available intravascular imaging-based physiologic indices, their diagnostic performance, and clinical application.

Association of the monocytes to high-density lipoprotein cholesterol ratio with in-stent neoatherosclerosis and plaque vulnerability: An optical coherence tomography study

BACKGROUND

Monocyte-to-high-density lipoprotein cholesterol ratio (MHR) is an independent predictor of atherosclerosis and in-stent restenosis (ISR). However, the association between MHR and the incidence of in-stent neoatherosclerosis (ISNA) remains to be validated.

METHODS

This study included 216 patients with acute coronary syndrome who had 220 ISR lesions and had undergone optical coherence tomography (OCT). All eligible patients were divided into three groups according to their MHR tertile level. OCT characteristics were comparatively analyzed between groups of different MHR levels, and univariate and multivariate logistic regression analyses were constructed to assess correlations between MHR level and ISNA as well as in-stent thin-cap fibroatheroma (TCFA). A receiver operating characteristic curve was used to determine the optimal MHR thresholds for predicting ISNA and in-stent TCFA.

RESULTS

The incidence of ISNA (70.3% vs. 61.1% vs. 20.3%, P < 0.001) and in-stent TCFA (40.5% vs. 31.9% vs. 6.8%, P < 0.001) was the highest in the third tertile, followed by the second and first tertiles, respectively. Multivariate analysis revealed that MHR was independently associated with ISNA (odds ratio [OR], 7.212; 95% confidence interval [CI], 1.287-40.416; P = 0.025) and in-stent TCFA (OR, 5.610; 95% CI, 1.743-18.051; P = 0.004) after adjusting for other clinical factors. The area under the curve was 0.745 (95% CI, 0.678-0.811; P < 0.001) for the prediction of ISNA and 0.718 (95% CI, 0.637-0.778; P < 0.001) for the prediction of in-stent TCFA.

CONCLUSION

MHR levels are an independent risk factor for ISNA.

Invasive coronary imaging of inflammation to further characterize high-risk lesions: what options do we have?

Coronary atherosclerosis remains a leading cause of morbidity and mortality worldwide. The underlying pathophysiology includes a complex interplay of endothelial dysfunction, lipid accumulation and inflammatory pathways. Multiple structural and inflammatory features of the atherosclerotic lesions have become targets to identify high-risk lesions. Various intracoronary imaging devices have been developed to assess the morphological, biocompositional and molecular profile of the intracoronary atheromata. These techniques guide interventional and therapeutical management and allow the identification and stratification of atherosclerotic lesions. We sought to provide an overview of the inflammatory pathobiology of atherosclerosis, distinct high-risk plaque features and the ability to visualize this process with contemporary intracoronary imaging techniques.

Cardiac Optical Coherence Tomography: History, Current Status, and Perspective

For more than 2 decades since the first imaging procedure was performed in a living patient, intravascular optical coherence tomography (OCT), with its unprecedented image resolution, has made significant contributions to cardiovascular medicine in the realms of vascular biology research and percutaneous coronary intervention. OCT has contributed to a better understanding of vascular biology by providing insights into the pathobiology of atherosclerosis, including plaque phenotypes and the underlying mechanisms of acute coronary syndromes such as plaque erosion, neoatherosclerosis, stent thrombosis, and myocardial infarction with nonobstructive coronary arteries. Moreover, OCT has been used as an adjunctive imaging tool to angiography for the guidance of percutaneous coronary intervention procedures to optimize outcomes. However, broader application of OCT has faced challenges, including subjective interpretation of the images and insufficient clinical outcome data. Future developments including artificial intelligence-assisted interpretation, multimodality catheters, and micro-OCT, as well as large prospective outcome studies could broaden the impact of OCT on cardiovascular medicine.

Coronary microevaginations characterize culprit plaques and their inflammatory microenvironment in a subtype of acute coronary syndrome with intact fibrous cap: results from the prospective translational OPTICO-ACS study

AIMS

Coronary microevaginations (CMEs) represent an outward bulge of coronary plaques and have been introduced as a sign of adverse vascular remodelling following coronary device implantation. However, their role in atherosclerosis and plaque destabilization in the absence of coronary intervention is unknown. This study aimed to investigate CME as a novel feature of plaque vulnerability and to characterize its associated inflammatory cell-vessel-wall interactions.

METHODS AND RESULTS

A total of 557 patients from the translational OPTICO-ACS study programme underwent optical coherence tomography imaging of the culprit vessel and simultaneous immunophenotyping of the culprit lesion (CL). Two hundred and fifty-eight CLs had a ruptured fibrous cap (RFC) and one hundred had intact fibrous cap (IFC) acute coronary syndrome (ACS) as an underlying pathophysiology. CMEs were significantly more frequent in CL when compared with non-CL (25 vs. 4%, P < 0.001) and were more frequently observed in lesions with IFC-ACS when compared with RFC-ACS (55.0 vs. 12.7%, P < 0.001). CMEs were particularly prevalent in IFC-ACS-causing CLs independent of a coronary bifurcation (IFC-ICB) when compared with IFC-ACS with an association to a coronary bifurcation (IFC-ACB, 65.4 vs. 43.7%, P = 0.030). CME emerged as the strongest independent predictor of IFC-ICB (relative risk 3.36, 95% confidence interval 1.67-6.76, P = 0.001) by multivariable regression analysis. IFC-ICB demonstrated an enrichment of monocytes in both culprit blood analysis (culprit ratio: 1.1 ± 0.2 vs. 0.9 ± 0.2, P = 0.048) and aspirated culprit thrombi (326 ± 162 vs. 96 ± 87 cells/mm2, P = 0.017), while IFC-ACB confirmed the accumulation of CD4+ T cells, as recently described.

CONCLUSION

This study provides novel evidence for a pathophysiological involvement of CME in the development of IFC-ACS and provides first evidence for a distinct pathophysiological pathway for IFC-ICB, driven by CME-derived flow disturbances and inflammatory activation involving the innate immune system.

TRIAL REGISTRATION

Registration of the study at clinicalTrials.gov (NCT03129503).

Relationship of Coronary Angiography-Derived Radial Wall Strain With Functional Significance, Plaque Morphology, and Clinical Outcomes

BACKGROUND

Coronary angiography-derived radial wall strain (RWS) is a newly developed index that can be readily accessed and describes the biomechanical features of a lesion.

OBJECTIVES

The authors sought to investigate the association of RWS with fractional flow reserve (FFR) and high-risk plaque (HRP), and their relative prognostic implications.

METHODS

We included 484 vessels (351 patients) deferred after FFR measurement with available RWS data and coronary computed tomography angiography. On coronary computed tomography angiography, HRP was defined as a lesion with both minimum lumen area <4 mm2 and plaque burden ≥70%. The primary outcome was target vessel failure (TVF), a composite of target vessel revascularization, target vessel myocardial infarction, or cardiac death.

RESULTS

The mean FFR and RWSmax were 0.89 ± 0.07 and 11.2% ± 2.5%, respectively, whereas 27.7% of lesions had HRP, 15.1% had FFR ≤0.80. An increase in RWSmax was associated with a higher risk of FFR ≤0.80 and HRP, which was consistent after adjustment for clinical or angiographic characteristics (all P < 0.05). An increment of RWSmax was related to a higher risk of TVF (HR: 1.23 [95% CI: 1.03-1.47]; P = 0.022) with an optimal cutoff of 14.25%. RWSmax >14% was a predictor of TVF after adjustment for FFR or HRP components (all P < 0.05) and showed a direct prognostic effect on TVF, not mediated by FFR ≤0.80 or HRP in the mediation analysis. When high RWSmax was added to FFR ≤0.80 or HRP, there were increasing outcome trends (all P for trend <0.001).

CONCLUSIONS

RWS was associated with coronary physiology and plaque morphology but showed independent prognostic significance.

Reproducibility of an artificial intelligence optical coherence tomography software for tissue characterization: Implications for the design of longitudinal studies

BACKGROUND

To assess the reproducibility of coronary tissue characterization by an Artificial Intelligence Optical Coherence Tomography software (OctPlus, Shanghai Pulse Medical Imaging Technology Inc.).

METHODS

74 patients presenting with multivessel ST-segment elevation myocardial infarction (STEMI) underwent optical coherence tomography (OCT) of the infarct-related artery at the end of primary percutaneous coronary intervention (PPCI) and during staged PCI (SPCI) within 7 days thereafter in the MATRIX (Minimizing Adverse Hemorrhagic Events by Transradial Access Site and angioX) Treatment-Duration study (ClinicalTrials.gov, NCT01433627). OCT films were run through the OctPlus software. The same region of interest between either side of the stent and the first branch was identified on OCT films for each patient at PPCI and SPCI, thus generating 94 pairs of segments. 42 pairs of segments were re-analyzed for intra-software difference. Five plaque characteristics including cholesterol crystal, fibrous tissue, calcium, lipid, and macrophage content were analyzed for various parameters (span angle, thickness, and area).

RESULTS

There was no statistically significant inter-catheter (between PPCI and SPCI) or intra-software difference in the mean values of all the parameters. Inter-catheter correlation for area was best seen for calcification [intraclass correlation coefficient (ICC) 0.86], followed by fibrous tissue (ICC 0.87), lipid (ICC 0.62), and macrophage (ICC 0.43). Some of the inter-catheter relative differences for area measurements were large: calcification 9.75 %; cholesterol crystal 74.10 %; fibrous tissue 5.90 %; lipid 4.66 %; and macrophage 1.23 %. By the intra-software measurements, there was an excellent correlation (ICC > 0.9) for all tissue types. The relative differences for area measurements were: calcification 0.64 %; cholesterol crystal 5.34 %; fibrous tissue 0.19 %; lipid 1.07 %; and macrophage 0.60 %. Features of vulnerable plaque, minimum fibrous cap thickness and lipid area showed acceptable reproducibility.

CONCLUSION

The present study demonstrates an overall good reproducibility of tissue characterization by the Artificial Intelligence Optical Coherence Tomography software. In future longitudinal studies, investigators may use discretion in selecting the imaging endpoints and sample size, accounting for the observed relative differences in this study.

Roadmap on the use of artificial intelligence for imaging of vulnerable atherosclerotic plaque in coronary arteries

Artificial intelligence (AI) is likely to revolutionize the way medical images are analysed and has the potential to improve the identification and analysis of vulnerable or high-risk atherosclerotic plaques in coronary arteries, leading to advances in the treatment of coronary artery disease. However, coronary plaque analysis is challenging owing to cardiac and respiratory motion, as well as the small size of cardiovascular structures. Moreover, the analysis of coronary imaging data is time-consuming, can be performed only by clinicians with dedicated cardiovascular imaging training, and is subject to considerable interreader and intrareader variability. AI has the potential to improve the assessment of images of vulnerable plaque in coronary arteries, but requires robust development, testing and validation. Combining human expertise with AI might facilitate the reliable and valid interpretation of images obtained using CT, MRI, PET, intravascular ultrasonography and optical coherence tomography. In this Roadmap, we review existing evidence on the application of AI to the imaging of vulnerable plaque in coronary arteries and provide consensus recommendations developed by an interdisciplinary group of experts on AI and non-invasive and invasive coronary imaging. We also outline future requirements of AI technology to address bias, uncertainty, explainability and generalizability, which are all essential for the acceptance of AI and its clinical utility in handling the anticipated growing volume of coronary imaging procedures.

Association Between Serum Uric Acid Levels and Neoatherosclerosis

Neoatherosclerosis is a major cause of stent failure after percutaneous coronary intervention. Metabolism such as hyperuricemia is associated with in-stent restenosis (ISR). However, the association between serum uric acid (sUA) levels and in-stent neoatherosclerosis (ISNA) has never been validated.A total of 216 patients with 220 ISR lesions who had undergone optical coherence tomography (OCT) of culprit stents were included in this study. According to their sUA levels, eligible patients were divided into two groups [normal-sUA group: sUA < 7 mg/dL, n = 126, and high-sUA group: sUA ≥ 7 mg/dL, n = 90]. OCT findings were analyzed and compared between the normal- and high-sUA groups.The incidence of ISNA (63.0% versus 43.0%, P = 0.004) was significantly higher in the high-sUA group than in the normal-sUA group. Lipid plaques (66.3% versus 43.0%, P < 0.001) and thin-cap fibroatheroma (38.0% versus 18.0%, P = 0.001) were observed more frequently in the restenotic tissue structure in patients in the high-sUA group than in those in the normal-sUA group. Meanwhile, univariate (OR: 1.208, 95% CI: 1.037-1.407; P = 0.015) and multivariate (OR: 1.254, 95% CI: 1.048-1.501; P = 0.013) logistic regression analyses indicated that sUA levels were an independent risk factor for ISNA after adjusting for relevant risk factors.The high-sUA levels were an independent risk factor for the occurrence of neoatherosclerosis in patients with ISR via OCT.

Higher triglyceride levels are associated with the higher prevalence of layered plaques in non-culprit coronary plaques

High triglyceride (TG) levels have been recognized as a risk factor for cardiovascular events in patients with coronary artery disease (CAD). This study aimed to clarify the association between TG levels and characteristics of non-culprit coronary plaques in patients with CAD. A total of 531 consecutive patients with stable CAD who underwent percutaneous coronary intervention for culprit lesions and optical coherence tomography (OCT) assessment of non-culprit plaques in the culprit vessel were included in this study. The morphology of the non-culprit plaques assessed by OCT imaging were compared between the higher TG (TG ≥ 150 mg/dL, n = 197) and lower TG (TG < 150 mg/dL, n = 334) groups. The prevalence of layered plaques (40.1 vs. 27.5%, p = 0.004) was significantly higher in the higher TG group than in the lower TG group, although the prevalence of other plaque components was comparable between the two groups. High TG levels were an independent factor for the presence of layered plaques (odds ratio 1.761, 95% confidence interval 1.213-2.558, p = 0.003) whereas high low-density lipoprotein cholesterol levels (≥ 140 mg/dL) and low eicosapentaenoic acid/arachidonic acid ratios (< 0.4) were independently associated with a higher prevalence of thin-cap fibroatheroma and macrophages. Higher TG levels were associated with a higher prevalence of layered plaques in non-culprit plaques among patients with stable CAD. These results may partly explain the effect of TG on the progression of coronary plaques and the increased incidence of recurrent events in patients with CAD.

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

AIMS

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

METHODS AND RESULTS

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

CONCLUSION

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

Effect of PCSK9 antibodies on coronary plaque regression and stabilization derived from intravascular imaging in patients with coronary artery disease: A meta-analysis

BACKGROUND

Despite extensive evidence demonstrating the beneficial effects of the additional PCSK9 antibodies with high-density statins treatment on cardiovascular clinical outcomes, the potent causes underlying these effects remain elusive. This meta-analysis aimed at exploring the underlying causes to assess the effect of PCSK9 antibodies on the regression and stabilization of coronary plaque derived from intravascular imaging in statin-treated patients with coronary artery disease (CAD).

METHODS

PubMed, Embase, and Cochrane Library were searched from inception to February 1, 2023, for randomized controlled trials (RCTs), nonrandomized studies without language restrictions if they described the association between PCSK9 antibodies with coronary plaque regression and stabilization evaluated by intravascular imaging in statin-treated patients with CAD. Meta-analyses were performed for mean difference (MD) and odds ratio (OR) using a random-effects model. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

RESULTS

A total of 9 studies (7 RCTs and 2 non-RCTs) with 2290 CAD patients were identified and included. Among statin-treated CAD patients, the addition use of PCSK9 antibodies was associated with IVUS-derived percent atheroma volume (PAV) (4 studies with 1875 participants; MD, -1.26; 95% CI, -1.51 to -1.00; P < 0.01), total atheroma volume (TAV) (4 studies with 1875 participants; MD, -7.23; 95% CI, -11.28 to -3.18; P < 0.01), incidence of PAV regression (4 studies with 1875 participants; OR, 2.24; 95% CI, 1.81 to 2.77; P < 0.01) and incidence of TAV regression (3 studies with 1256 participants; OR, 1.66; 95% CI, 1.33 to 2.09; P < 0.01) in Caucasians instead of Asians from multiple countries; OCT-derived minimum fibrous cap thickness (FCT) (6 studies with 841 participants; MD, 25.16; 95% CI, 14.06 to 36.27; P < 0.01), incidence of thin-capped fibroatheroma (TCFA) regression (2 studies with 222 participants; OR, 2.56; 95% CI, 1.42 to 4.61; P < 0.01) and maximum lipid arc (4 studies with 280 participants; MD, -14.96; 95% CI, -22.10 to -7.83; P < 0.01) in Asians and Caucasians without races restrictions.

CONCLUSIONS

PCSK9 antibodies resulted in significantly greater coronary plaque regression and stabilization in statin-treated CAD patients, mostly Caucasians from multiple countries. Further studies are needed to assess the effect for Asian patients.

Fractional flow reserve versus intravascular imaging to guide decision-making for percutaneous coronary intervention in intermediate lesions: A meta-analysis

BACKGROUND

Both fractional flow reserve (FFR) and intravascular imaging (IVI) have been used to guide the decision-making for percutaneous coronary intervention (PCI) in intermediate coronary stenosis. Nevertheless, studies that directly compared the prognostic significance of these two strategies are scarce.

AIMS

The aim of this meta-analyses was to evaluate the impact of FFR versus IVI to guide the decision-making in PCI for intermediate stenosis on clinical outcomes.

METHODS

We systematically searched PubMed, Embase, Cochrane, and relevant database from inception date to September 2022 for observational studies and randomized clinical trials (RCTs) which compared FFR and IVI-based decision-making in PCI for intermediate stenosis. The primary outcome was a composite of major adverse cardiac event (MACE). Pooled risk ratios (RR) were calculated using random effects models and heterogeneity were evaluated with the I2 statistic.

RESULTS

We identified 5 studies (3 RCTs and 2 observational studies) with 3208 patients. The follow-up duration ranged from 12 to 24 months. Among five studies, four compared FFR with intravascular ultrasound while one compared FFR with optical coherence tomography. There was no statistically difference between FFR and IVI in the incidence of MACE (RR: 1.19; 95% confidence interval: 0.85-1.68; p = 0.31) and its individual components. These results were consistent regardless of various cut-off value of PCI across the studies. Compared with IVI, FFR was associated with a lower PCI rate (37.0% vs. 60.3%; p < 0.001).

CONCLUSIONS

The decision to perform PCI for intermediate stenosis guided by FFR or IVI showed a similar clinical outcome. The use of FFR significantly reduced the need for PCI.

Practical Application of Coronary Physiologic Assessment: Asia-Pacific Expert Consensus Document: Part 2

Coronary physiologic assessment is performed to measure coronary pressure, flow, and resistance or their surrogates to enable the selection of appropriate management strategy and its optimization for patients with coronary artery disease. The value of physiologic assessment is supported by a large body of clinical data that has led to major recommendations in all practice guidelines. This expert consensus document aims to convey practical and balanced recommendations and future perspectives for coronary physiologic assessment for physicians and patients in the Asia-Pacific region, based on updated information in the field that includes both wire- and image-based physiologic assessment. This is Part 2 of the whole consensus document, which provides theoretical and practical information on physiologic indexes for specific clinical conditions and patient statuses.

Association of LDL-C level with neoatherosclerosis and plaque vulnerability in patients with late restenosis: an optical coherence tomography study

Neoatherosclerosis (NA) is a significant contributor to late stent failure; however, predictors of late in-stent restenosis (ISR) with NA have not been systematically reported. This study aimed to identify predictors of NA incidence and plaque vulnerability in patients with late ISR and the role of low-density lipoprotein cholesterol (LDL-C) levels in this process. A total of 216 patients with 216 lesions who underwent optical coherence tomography (OCT) before interventional procedure for late drug-eluting stent ISR were enrolled and divided into NA and non-NA groups based on OCT findings. Results showed that higher LDL-C levels were associated with NA, thin-cap fibroatheroma (TCFA), intimal disruption, plaque erosion, and thrombosis. Multivariate regression analysis revealed that the LDL-C level was an independent risk factor for NA and TCFA. The LDL-C levels exhibited a significant predictive value for NA and TCFA, surpassing other factors such as stent age and other lipid types. In conclusion, a high LDL-C level is an independent predictor of NA incidence and plaque vulnerability in patients with late ISR.

Fractional Flow Reserve-Negative High-Risk Plaques and Clinical Outcomes After Myocardial Infarction

Importance

Even after fractional flow reserve (FFR)-guided complete revascularization, patients with myocardial infarction (MI) have high rates of recurrent major adverse cardiovascular events (MACE). These recurrences may be caused by FFR-negative high-risk nonculprit lesions.

Objective

To assess the association between optical coherence tomography (OCT)-identified high-risk plaques of FFR-negative nonculprit lesions and occurrence of MACE in patients with MI.

Design, Setting, and Participants

PECTUS-obs (Identification of Risk Factors for Acute Coronary Events by OCT After STEMI [ST-segment elevation MI] and NSTEMI [non-STEMI] in Patients With Residual Non-flow Limiting Lesions) is an international, multicenter, prospective, observational cohort study. In patients presenting with MI, OCT was performed on all FFR-negative (FFR > 0.80) nonculprit lesions. A high-risk plaque was defined containing at least 2 of the following prespecified criteria: (1) a lipid arc at least 90°, (2) a fibrous cap thickness less than 65 μm, and (3) either plaque rupture or thrombus presence. Patients were enrolled from December 14, 2018, to September 15, 2020. Data were analyzed from December 2, 2022, to June 28, 2023.

Main Outcome and Measure

The primary end point of MACE, a composite of all-cause mortality, nonfatal MI, or unplanned revascularization, at 2-year follow-up was compared in patients with and without a high-risk plaque.

Results

A total of 438 patients were enrolled, and OCT findings were analyzable in 420. Among included patients, mean (SD) age was 63 (10) years, 340 (81.0) were men, and STEMI and non-STEMI were equally represented (217 [51.7%] and 203 [48.3%]). A mean (SD) of 1.17 (0.42) nonculprit lesions per patient was imaged. Analysis of OCT images revealed at least 1 high-risk plaque in 143 patients (34.0%). The primary end point occurred in 22 patients (15.4%) with a high-risk plaque and 23 of 277 patients (8.3%) without a high-risk plaque (hazard ratio, 1.93 [95% CI, 1.08-3.47]; P = .02), primarily driven by more unplanned revascularizations in patients with a high-risk plaque (14 of 143 [9.8%] vs 12 of 277 [4.3%]; P = .02).

Conclusions and Relevance

Among patients with MI and FFR-negative nonculprit lesions, the presence of a high-risk plaque is associated with a worse clinical outcome, which is mainly driven by a higher number of unplanned revascularizations. In a population with a high recurrent event rate despite physiology-guided complete revascularization, these results call for research on additional pharmacological or focal treatment strategies in patients harboring high-risk plaques.

The plaque hypothesis: understanding mechanisms of plaque progression and destabilization, and implications for clinical management

PURPOSE OF REVIEW

Major adverse cardiac events (MACE) typically arise from nonflow-limiting coronary artery disease and not from flow-limiting obstructions that cause ischemia. This review elaborates the current understanding of the mechanism(s) for plaque development, progression, and destabilization and how identification of these high-risk features can optimally inform clinical management.

RECENT FINDINGS

Advanced invasive and noninvasive coronary imaging and computational postprocessing enhance an understanding of pathobiologic/pathophysiologic features of coronary artery plaques prone to destabilization and MACE. Early investigations of high-risk plaques focused on anatomic and biochemical characteristics (large plaque burden, severe luminal obstruction, thin cap fibroatheroma morphology, and large lipid pool), but more recent studies underscore that additional factors, particularly biomechanical factors [low endothelial shear stress (ESS), high ESS gradient, plaque structural stress, and axial plaque stress], provide the critical incremental stimulus acting on the anatomic substrate to provoke plaque destabilization. These destabilizing features are often located in areas distant from the flow-limiting obstruction or may exist in plaques without any flow limitation. Identification of these high-risk, synergistic plaque features enable identification of plaques prone to destabilize regardless of the presence or absence of a severe obstruction (Plaque Hypothesis).

SUMMARY

Local plaque topography, hemodynamic patterns, and internal plaque constituents constitute high-risk features that may be located along the entire course of the coronary plaque, including both flow-limiting and nonflow-limiting regions. For coronary interventions to have optimal clinical impact, it will be critical to direct their application to the plaque area(s) at highest risk.

Long Noncoding RNA Gpr137b-ps Promotes Advanced Atherosclerosis via the Regulation of Autophagy in Macrophages

BACKGROUND

Current therapies cannot completely reverse advanced atherosclerosis. High levels of amino acids, induced by Western diet, stimulate mTORC1 (mammalian target of rapamycin complex 1)-autophagy defects in macrophages, accelerating atherosclerotic plaque progression. In addition, autophagy-lysosomal dysfunction contributes to plaque necrotic core enlargement and lipid accumulation. Therefore, it is essential to investigate the novel mechanism and molecules to reverse amino acid-mTORC1-autophagy signaling dysfunction in macrophages of patients with advanced atherosclerosis.

METHODS

We observed that Gpr137b-ps (G-protein-coupled receptor 137B, pseudogene) was upregulated in advanced atherosclerotic plaques. The effect of Gpr137b-ps on the progression of atherosclerosis was studied by generating advanced plaques in ApoE-/- mice with cardiac-specific knockout of Gpr137b-ps. Bone marrow-derived macrophages and mouse mononuclear macrophage cell line RAW264.7 cells were subjected to starvation or amino acid stimulation to study amino acid-mTORC1-autophagy signaling. Using both gain- and loss-of-function approaches, we explored the mechanism of Gpr137b-ps-regulated autophagy.

RESULTS

Our results demonstrated that Gpr137b-ps deficiency led to enhanced autophagy in macrophages and reduced atherosclerotic lesions, characterized by fewer necrotic cores and less lipid accumulation. Knockdown of Gpr137b-ps increased autophagy and prevented amino acid-induced mTORC1 signaling activation. As the downstream binding protein of Gpr137b-ps, HSC70 (heat shock cognate 70) rescued the impaired autophagy induced by Gpr137b-ps. Furthermore, Gpr137b-ps interfered with the HSC70 binding to G3BP (Ras GTPase-activating protein-binding protein), which tethers the TSC (tuberous sclerosis complex) complex to lysosomes and suppresses mTORC1 signaling. In addition to verifying that the NTF2 (nuclear transport factor 2) domain of G3BP binds to HSC70 by in vitro protein synthesis, we further demonstrated that HSC70 binds to the NTF2 domain of G3BP through its W90-F92 motif by using computational modeling.

CONCLUSIONS

These findings reveal that Gpr137b-ps plays an essential role in the regulation of macrophage autophagy, which is crucial for the progression of advanced atherosclerosis. Gpr137b-ps impairs the interaction of HSC70 with G3BP to regulate amino acid-mTORC1-autophagy signaling, and these results provide a new potential therapeutic direction for the treatment of advanced atherosclerosis.

Coronary Atherosclerosis Phenotypes in Focal and Diffuse Disease

BACKGROUND

The interplay between coronary hemodynamics and plaque characteristics remains poorly understood.

OBJECTIVES

The aim of this study was to compare atherosclerotic plaque phenotypes between focal and diffuse coronary artery disease (CAD) defined by coronary hemodynamics.

METHODS

This multicenter, prospective, single-arm study was conducted in 5 countries. Patients with functionally significant lesions based on an invasive fractional flow reserve ≤0.80 were included. Plaque analysis was performed by using coronary computed tomography angiography and optical coherence tomography. CAD patterns were assessed using motorized fractional flow reserve pullbacks and quantified by pullback pressure gradient (PPG). Focal and diffuse CAD was defined according to the median PPG value.

RESULTS

A total of 117 patients (120 vessels) were included. The median PPG was 0.66 (IQR: 0.54-0.75). According to coronary computed tomography angiography analysis, plaque burden was higher in patients with focal CAD (87% ± 8% focal vs 82% ± 10% diffuse; P = 0.003). Calcifications were significantly more prevalent in patients with diffuse CAD (Agatston score per vessel: 51 [IQR: 11-204] focal vs 158 [IQR: 52-341] diffuse; P = 0.024). According to optical coherence tomography analysis, patients with focal CAD had a significantly higher prevalence of circumferential lipid-rich plaque (37% focal vs 4% diffuse; P = 0.001) and thin-cap fibroatheroma (TCFA) (47% focal vs 10% diffuse; P = 0.002). Focal disease defined by PPG predicted the presence of TCFA with an area under the curve of 0.73 (95% CI: 0.58-0.87).

CONCLUSIONS

Atherosclerotic plaque phenotypes associate with intracoronary hemodynamics. Focal CAD had a higher plaque burden and was predominantly lipid-rich with a high prevalence of TCFA, whereas calcifications were more prevalent in diffuse CAD. (Precise Percutaneous Coronary Intervention Plan [P3]; NCT03782688).

Concomitant Coronary Atheroma Regression and Stabilization in Response to Lipid-Lowering Therapy

BACKGROUND

The frequency, characteristics, and outcomes of patients treated with high-intensity lipid-lowering therapy and showing concomitant atheroma volume reduction, lipid content reduction, and increase in fibrous cap thickness (ie, triple regression) are unknown.

OBJECTIVES

This study was designed to investigate rates, determinants, and prognostic implications of triple regression in patients presenting with acute myocardial infarction and treated with high-intensity lipid-lowering therapy.

METHODS

The PACMAN-AMI (Effects of the PCSK9 Antibody Alirocumab on Coronary Atherosclerosis in Patients with Acute Myocardial Infarction) trial used serial intravascular ultrasound, near-infrared spectroscopy, and optical coherence tomography to compare the effects of alirocumab vs placebo in patients receiving high-intensity statin therapy. Triple regression was defined by the combined presence of percentage of atheroma volume reduction, maximum lipid core burden index within 4 mm reduction, and minimal fibrous cap thickness increase. Clinical outcomes at 1-year follow-up were assessed.

RESULTS

Overall, 84 patients (31.7%) showed triple regression (40.8% in the alirocumab group vs 23.0% in the placebo group; P = 0.002). On-treatment low-density lipoprotein cholesterol levels were lower in patients with vs without triple regression (between-group difference: -27.1 mg/dL; 95% CI: -37.7 to -16.6 mg/dL; P < 0.001). Triple regression was independently predicted by alirocumab treatment (OR: 2.83; 95% CI: 1.57-5.16; P = 0.001) and a higher baseline maximum lipid core burden index within 4 mm (OR: 1.03; 95% CI: 1.01-1.06; P = 0.013). The composite clinical endpoint of death, myocardial infarction, and ischemia-driven revascularization occurred less frequently in patients with vs without triple regression (8.3% vs 18.2%; P = 0.04).

CONCLUSIONS

Triple regression occurred in one-third of patients with acute myocardial infarction who were receiving high-intensity lipid-lowering therapy and was associated with alirocumab treatment, higher baseline lipid content, and reduced cardiovascular events. (Vascular Effects of Alirocumab in Acute MI-Patients [PACMAN-AMI]; NCT03067844).

Morphological Characteristics of Culprit Plaques in Acute Myocardial Infarction Patients With Different Scores of Type A Personality - An Intravascular Optical Coherence Tomography Study

BACKGROUND

Previous studies have suggested a relationship between type A personality and the occurrence of coronary artery disease, so we used intravascular optical coherence tomography (OCT) to investigate the morphological characteristics of culprit plaques in acute myocardial infarction (AMI) patients with different scores of type A personality.Methods and Results: A total of 221 AMI patients who underwent preintervention imaging of culprit lesions and an assessment of type A behavior pattern were included. According to the scores for the behavior questionnaire, these patients were divided into 3 groups: non-type A personality (n=91), intermediate personality (n=73), and type A personality (n=57). Patients with type A personality were younger (P=0.003) and had a higher level of total cholesterol (P=0.029) and more severe luminal stenosis (P=0.046). In addition, the prevalence of microchannels (P<0.001), macrophage accumulation (P<0.001), and plaque rupture (P=0.010) with greater number (P<0.001), cavity angle (P<0.001), and length (P<0.001) was highest in the type A personality group.

CONCLUSIONS

The culprit lesions of AMI patients with increased scores for type A personality had more severe coronary luminal stenosis, and the proportion of vulnerable features was increased.

Long-term prognostic value of quantitative-flow-ratio-concordant revascularization in stable coronary artery disease

OBJECTIVES

Confirming the prognostic value of global QFR and evaluating the long-term prognosis of QFR-concordant therapy in stable coronary artery disease.

BACKGROUND

Wire-based functional evaluation of coronary disease is linked to patient's prognosis. Quantitative Flow Ratio (QFR) is a newer index of computational physiology, linked to clinical outcomes and prognosis at 1 year follow-up. Long-term prognosis of QFR-concordant revascularization in stable coronary artery disease is however unknown hitherto.

METHODS

Consecutive patients with stable coronary disease undergoing coronary angiography were included. Centralized and blinded QFR analysis of three coronary territories was performed. Three vessel QFR (3vQFR) was defined as the sum of the basal QFR of each coronary territory. QFR-concordant revascularization was met if all significant lesions (QFR ≤ 0.80) were revascularized and all non-significant lesions (QFR > 0.80) were not; otherwise, the case was defined as QFR-discordant revascularization. Patient-oriented composite end-point (POCE) of cardiac death, myocardial infarction and unscheduled revascularization was the primary endpoint.

RESULTS

A total of 803 patients from six high-volume centers were included. Canadian Cardiovascular Society (CCS) class II angina was the most frequent (48.9%) clinical presentation. Median of follow-up was 68.8 months. 3vQFR was an independent predictor of POCE (HR 1.79 CI95% 1.01-3.18), with 2.75 as optimal cut-off value, irrespective of the therapy received. QFR-discordant revascularization (QFR+/Revascularization- or QFR-/Revascularization+) was an independent predictor of POCE in multivariate analysis (HR 1.65, CI 95% 1.03-2.64).

CONCLUSION

Global burden of epicardial coronary atherosclerosis, as evaluated by 3vQFR, as well as QFR-discordant therapy are independent predictors of adverse clinical outcome at long-term follow-up in stable coronary artery disease.

Identifying and Treating Vulnerable Atherosclerotic Plaques

Acute coronary syndromes and, in particular, ST-elevation myocardial infarction are usually caused by coronary thrombosis in which the thrombus develops either on a disrupted plaque (usually a thin-capped fibroatheroma) or an eroded atherosclerotic plaque. These thrombus-prone plaques are vulnerable or high-risk. Although, traditionally, cardiologists have concentrated on treating significant coronary obstruction, there has been great interest over the last 2 decades in possibly preventing the thrombotic causes of myocardial infarction/sudden coronary death by mostly identifying and stabilizing these asymptomatic vulnerable or high-risk plaques, which, at least on invasive angiography, are mostly nonobstructive. Computed tomographic angiography and intravascular imaging during invasive coronary angiography have now been shown to identify a majority of these vulnerable or high-risk plaques before symptoms, thus opening up new preventive strategies. In conclusion, this article discusses the identification and management of these thrombus-prone lesions and patients with these lesions either with noninvasive techniques and systemic therapies or possibly through a new and bold interventional paradigm.

Acute Coronary Syndrome with Non-Obstructive Plaque on Angiography and Features of Vulnerable Plaque on Intracoronary Optical Coherence Tomography

Optical coherence tomography (OCT) has a high spatial resolution and is useful in identifying coronary lesions with high-risk features (vulnerable plaques). These plaques are strongly associated with acute coronary syndrome (ACS). In this report, we present the case of a 43-year-old male patient presenting with typical chest pain that began three hours prior to admission. The patient exhibited an elevation of the ST segments of the anterior and lateral walls. Invasive stratification revealed a 40% lesion in the middle segment of the left anterior descending (LAD) artery. The patient was given optimized clinical treatment as he had a nonobstructive lesion in the LAD at the time of angiography. During the treatment, the patient continued to complain of angina on exertion. A follow-up coronary angiography, along with OCT analysis of the middle-to-moderate lesion in the LAD, revealed a plaque predominantly rich in lipids with signs of vulnerability. A percutaneous coronary intervention was performed. The patient's recovery was uneventful, and he was discharged the day after the procedure. This case illustrates the evolution of intravascular imaging, particularly OCT, in the detection of vulnerable plaques.

Why percutaneous revascularisation might not reduce the risk of myocardial infarction and mortality in patients with stable CAD?

Percutaneous coronary intervention (PCI) is widely adopted to treat chronic coronary artery disease. Numerous randomised trials have been conducted to test whether PCI may provide any prognostic advantage over oral medical therapy (OMT) alone, without definitive results. This has maintained the paradigm of OMT as the first-line standard of care for patients, reserving PCI for symptom control. In this review, we discuss the current evidence in favour and against PCI in stable coronary syndromes and highlight the pitfalls of the available studies. We offer a critical appraisal of the possible reasons why the existing data does not provide evidence supporting the role of PCI in improving clinical outcomes in patients with stable coronary syndromes.

Preventive PCI or medical therapy alone for vulnerable atherosclerotic coronary plaque: Rationale and design of the randomized, controlled PREVENT trial

BACKGROUND

Acute coronary syndromes are commonly caused by the rupture of vulnerable plaque, which often appear angiographically not severe. Although pharmacologic management is considered standard therapy for stabilizing plaque vulnerability, the potential role of preventive local treatment for vulnerable plaque has not yet been determined. The PREVENT trial was designed to compare preventive percutaneous coronary intervention (PCI) plus optimal medical therapy (OMT) with OMT alone in patients with functionally nonsignificant high-risk vulnerable plaques.

METHODS

The PREVENT trial is a multinational, multicenter, prospective, open-label, active-treatment-controlled randomized trial. Eligible patients have at least 1 angiographically significant stenosis (diameter stenosis >50% by visual estimation) without functional significance (fractional flow reserve [FFR] >0.80). Target lesions are assessed by intracoronary imaging and must meet at least 2 imaging criteria for vulnerable plaque; (1) minimal lumen area <4.0 mm2; (2) plaque burden >70%; (3) maximal lipid core burden index in a 4 mm segment >315 by near infrared spectroscopy; and (4) thin cap fibroatheroma as determined by virtual histology or optical coherence tomography. Enrolled patients are randomly assigned in a 1:1 ratio to either preventive PCI with either bioabsorbable vascular scaffolds or metallic everolimus-eluting stents plus OMT or OMT alone. The primary endpoint is target-vessel failure, defined as the composite of death from cardiac causes, target-vessel myocardial infarction, ischemic-driven target-vessel revascularization, or hospitalization for unstable or progressive angina, at 2 years after randomization.

RESULTS

Enrollment of a total of 1,608 patients has been completed. Follow-up of the last enrolled patient will be completed in September 2023 and primary results are expected to be available in early 2024.

CONCLUSIONS

The PREVENT trial is the first large-scale, randomized trial to evaluate the effect of preventive PCI on non-flow-limiting vulnerable plaques containing multiple high-risk features that is appropriately powered for clinical outcomes. PREVENT will provide compelling evidence as to whether preventive PCI of vulnerable plaques plus OMT improves patient outcomes compared with OMT alone.

CLINICAL TRIAL REGISTRATION

URL: https://www.

CLINICALTRIALS

gov. Unique identifier: NCT02316886.

KEY POINTS

The PREVENT trial is the first, large-scale randomized clinical trial to evaluate the effect of preventive PCI on non-flow-limiting vulnerable plaque with high-risk features. It will provide compelling evidence to determine whether PCI of focal vulnerable plaques on top of OMT improves patient outcomes.

Management of Residual Risk in Chronic Coronary Syndromes. Clinical Pathways for a Quality-Based Secondary Prevention

Chronic coronary syndrome (CCS), which encompasses a broad spectrum of clinical presentations of coronary artery disease (CAD), is the leading cause of morbidity and mortality worldwide. Recent guidelines for the management of CCS emphasize the dynamic nature of the CAD process, replacing the term "stable" with "chronic", as this disease is never truly "stable". Despite significant advances in the treatment of CAD, patients with CCS remain at an elevated risk of major cardiovascular events (MACE) due to the so-called residual cardiovascular risk. Several pathogenetic pathways (thrombotic, inflammatory, metabolic, and procedural) may distinctly contribute to the residual risk in individual patients and represent a potential target for newer preventive treatments. Identifying the level and type of residual cardiovascular risk is essential for selecting the most appropriate diagnostic tests and follow-up procedures. In addition, new management strategies and healthcare models could further support available treatments and lead to important prognostic benefits. This review aims to provide an overview of the diagnostic and therapeutic challenges in the management of patients with CCS and to promote more effective multidisciplinary care.

Cardiac Computed Tomography Angiography in CAD Risk Stratification and Revascularization Planning

PURPOSE OF REVIEW

Functional stress testing is frequently used to assess for coronary artery disease (CAD) in symptomatic, stable patients with low to intermediate pretest probability. However, patients with highly vulnerable plaque may have preserved luminal patency and, consequently, a falsely negative stress test. Cardiac computed tomography angiography (CCTA) has emerged at the forefront of primary prevention screening and has excellent agency in ruling out obstructive CAD with high negative predictive value while simultaneously characterizing nonobstructive plaque for high-risk features, which invariably alters risk-stratification and pre-procedural decision making.

RECENT FINDINGS

We review the literature detailing the utility of CCTA in its ability to risk-stratify patients with CAD based on calcium scoring as well as high-risk phenotypic features and to qualify the functional significance of stenotic lesions.

SUMMARY

Calcium scores ≥ 100 should prompt consideration of statin and aspirin therapy. Spotty calcifications < 3 mm, increased non-calcified plaque > 4 mm3 per mm of the vessel wall, low attenuation < 30 HU soft plaque and necrotic core with a rim of higher attenuation < 130 HU, and a positive remodeling index ratio > 1.1 all confer additive risk for acute plaque rupture when present. Elevations in the perivascular fat attenuation index > -70.1 HU are a strong predictor of all-cause mortality and can further the risk stratification of patients in the setting of a non-to-minimal plaque burden. Lastly, a CT-derived fractional flow reserve (FFRCT) < 0.75 or values from 0.76 to 0.80 in conjunction with additional risk factors is suggestive of flow-limiting disease that would benefit from invasive testing. The wealth of information available through CCTA can allow clinicians to risk-stratify patients at elevated risk for an acute ischemic event and engage in advanced revascularization planning.

Coronary Physiology-Based Approaches for Plaque Vulnerability: Implications for Risk Prediction and Treatment Strategies

In the catheterization laboratory, the measurement of physiological indexes can help identify functionally significant lesions and has become one of the standard methods to guide treatment decision-making. Plaque vulnerability refers to a coronary plaque susceptible to rupture, enabling risk prediction before coronary events, and it can be detected by defining a certain type of plaque morphology on coronary imaging modalities. Although coronary physiology and plaque vulnerability have been considered different attributes of coronary artery disease, the underlying pathophysiological basis and clinical data indicate a strong correlation between coronary hemodynamic properties and vulnerable plaque. In prediction of coronary events, emerging data have suggested independent and additional implications of a physiology-based approach to a plaque-based approach. This review covers the fundamental interplay between coronary physiology and plaque morphology during disease progression with clinical data supporting this relationship and examines the clinical relevance of physiological indexes in prediction of clinical outcomes and therapeutic decision-making along with plaque vulnerability.

Novel near-infrared spectroscopy-intravascular ultrasound-based deep-learning methodology for accurate coronary computed tomography plaque quantification and characterization

Aims

Coronary computed tomography angiography (CCTA) is inferior to intravascular imaging in detecting plaque morphology and quantifying plaque burden. We aim to, for the first time, train a deep-learning (DL) methodology for accurate plaque quantification and characterization in CCTA using near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS).

Methods and results

Seventy patients were prospectively recruited who underwent CCTA and NIRS-IVUS imaging. Corresponding cross sections were matched using an in-house developed software, and the estimations of NIRS-IVUS for the lumen, vessel wall borders, and plaque composition were used to train a convolutional neural network in 138 vessels. The performance was evaluated in 48 vessels and compared against the estimations of NIRS-IVUS and the conventional CCTA expert analysis. Sixty-four patients (186 vessels, 22 012 matched cross sections) were included. Deep-learning methodology provided estimations that were closer to NIRS-IVUS compared with the conventional approach for the total atheroma volume (ΔDL-NIRS-IVUS: -37.8 ± 89.0 vs. ΔConv-NIRS-IVUS: 243.3 ± 183.7 mm3, variance ratio: 4.262, P < 0.001) and percentage atheroma volume (-3.34 ± 5.77 vs. 17.20 ± 7.20%, variance ratio: 1.578, P < 0.001). The DL methodology detected lesions more accurately than the conventional approach (Area under the curve (AUC): 0.77 vs. 0.67, P < 0.001) and quantified minimum lumen area (ΔDL-NIRS-IVUS: -0.35 ± 1.81 vs. ΔConv-NIRS-IVUS: 1.37 ± 2.32 mm2, variance ratio: 1.634, P < 0.001), maximum plaque burden (4.33 ± 11.83% vs. 5.77 ± 16.58%, variance ratio: 2.071, P = 0.004), and calcific burden (-51.2 ± 115.1 vs. -54.3 ± 144.4, variance ratio: 2.308, P < 0.001) more accurately than conventional approach. The DL methodology was able to segment a vessel on CCTA in 0.3 s.

Conclusions

The DL methodology developed for CCTA analysis from co-registered NIRS-IVUS and CCTA data enables rapid and accurate assessment of lesion morphology and is superior to expert analysts (Clinicaltrials.gov: NCT03556644).

Pancoronary plaque characteristics and clinical outcomes in acute coronary syndrome patients with cancer history

BACKGROUND AND AIMS

The prevalence of acute coronary syndrome (ACS) patients with cancer history is increasing and it is associated with higher mortality. However, there is limited evidence on the characteristics of coronary plaque in ACS patients with cancer history. This study explored the pancoronary plaque characteristics in ACS patients with cancer history by optical coherence tomography (OCT).

METHODS

A total of 306 ACS patients treated by 3-vessel OCT at the time of percutaneous coronary intervention (PCI) were included, retrospectively. Patients were divided into two groups according to the presence or absence of cancer history: one group with cancer history (n = 98) and a matched group without cancer history (n = 208).

RESULTS

A total of 314 culprit lesions and 514 nonculprit lesions were identified by OCT in this study. In culprit lesions, ACS patients with cancer history had higher incidence of thin cap fibroatheroma (TCFA) (p = 0.016), cholesterol crystals (p = 0.028), calcification (p = 0.001) and thrombus (p = 0.001), and had thinner fibrous cap thickness (FCT) (p = 0.011), greater maximum lipid arc (p = 0.042) and lipid index (p < 0.001), compared to matched ACS patients without cancer history. In nonculprit lesions, ACS patients with cancer history had higher prevalence of high-risk plaque (14.7% vs. 7.7%, p = 0.017), nonculprit rupture (14.7% vs. 6.3%, p = 0.003), and TCFA (52.2% vs. 28.3%, p < 0.001), and had higher incidence of calcification (p = 0.003), thrombus (p = 0.029), cholesterol crystals (p = 0.002) and microchannels (p = 0.029). These non-culprit lesions had longer lesion length (p = 0.001), thinner FCT (p < 0.001), greater maximum lipid arc (p = 0.016) and lipid index (p < 0.001).

CONCLUSIONS

ACS patients with cancer history showed more high-risk plaque features in culprit and nonculprit lesions, compared with ACS patients without cancer history. Therefore, ACS patients with cancer history may have greater pancoronary vulnerability. This may predict a poorer prognosis for ACS patients with cancer history.