Clinical Outcome of Nonculprit Plaque Ruptures in Patients With Acute Coronary Syndrome in the PROSPECT Study

Meta-Analysis of Physiology-Guided Complete or Culprit Lesion-Only Percutaneous Coronary Interventions in Myocardial Infarction

Whether physiology-guided complete revascularization of nonculprit lesions is superior to culprit lesion-only percutaneous coronary intervention (PCI) in patients with myocardial infarction (MI) and multivessel disease remains debated. Online databases were searched for randomized controlled trials comparing physiology-guided complete revascularization and culprit lesion-only PCI in patients with MI. The outcomes of interest were all-cause death, cardiovascular (CV) death, repeat revascularization, MI, stent thrombosis, and contrast-associated nephropathy/acute kidney injury. Pooled odds ratios, along with 95% confidence intervals (CI) were calculated. A total of 4,849 patients (n = 2,288 physiology-guided complete revascularization, n = 2,561 culprit lesion-only PCI) were included. The mean age was 66 years and 76% were men. At a mean follow-up of 2.5 years, physiology-guided complete revascularization was associated with significant reductions in CV death (odds ratio 0.72, 95% CI 0.54 to 0.97, p = 0.03) and repeat revascularizations (0.50, 95% CI 0.38 to 0.66, p <0.00001) compared with culprit lesion-only PCI. There were no differences between the 2 approaches in all-cause death (0.91, 95% CI 0.69 to 1.19, p = 0.50), MI (0.85, 95% CI 0.59 to 1.21, p = 0.36), stent thrombosis (1.24, 95% CI 0.58 to 2.69, p = 0.58), and contrast-associated nephropathy/acute kidney injury (1.07, 95% CI 0.88 to 1.31, p = 0.50). In conclusion, among patients with MI and multivessel disease, physiology-guided complete revascularization was associated with significant reductions in CV death and revascularizations compared with culprit lesion-only PCI.

Routine Stress Testing After PCI in Patients With and Without Acute Coronary Syndrome: A Secondary Analysis of the POST-PCI Randomized Clinical Trial

Importance

The appropriate follow-up surveillance strategy for patients with acute coronary syndrome (ACS) who have undergone percutaneous coronary intervention (PCI) remains unknown.

Objective

To assess clinical outcomes in patients with and without ACS who have undergone high-risk PCI according to a follow-up strategy of routine stress testing at 12 months after PCI vs standard care alone.

Design, Setting, and Participants

The POST-PCI (Pragmatic Trial Comparing Symptom-Oriented vs Routine Stress Testing in High-Risk Patients Undergoing Percutaneous Coronary Intervention) trial was a randomized clinical trial that compared follow-up strategies of routine functional testing vs standard care alone 12 months after high-risk PCI. Patients were categorized as presenting with or without ACS. Patients were enrolled in the trial from November 2017 through September 2019, and patients were randomized from 11 sites in South Korea; data analysis was performed in 2022.

Intervention

Patients categorized as presenting with or without ACS were randomized to either a routine functional testing or standard care alone follow-up strategy 12 months after high-risk PCI.

Main Outcomes and Measures

The primary outcome was a composite of death from any cause, myocardial infarction, or hospitalization for unstable angina at 2 years following randomization. Kaplan-Meier event rates through 2 years and Cox model hazard ratios (HRs) were generated, and interactions were tested.

Results

Of 1706 included patients, 350 patients (20.5%) were female, and the mean (SD) patient age was 64.7 (10.3) years. In total, 526 patients (30.8%) presented with ACS. Compared with those without ACS, patients with ACS had a 55% greater risk of the primary outcome (HR, 1.55; 95% CI, 1.03-2.33; P = .03) due to higher event rates in the first year. The 2-year incidences of the primary outcome were similar between strategies of routine functional testing or standard care alone in patients with ACS (functional testing: 16 of 251 [6.6%]; standard care: 23 of 275 [8.5%]; HR, 0.76; 95% CI, 0.40-1.44; P = .39) and in patients without ACS (functional testing: 30 of 598 [5.1%]; standard care: 28 of 582 [4.9%]; HR, 1.04; 95% CI, 0.62-1.74; P = .88) (P for interaction for ACS = .45). Although a landmark analysis suggested that the rates of invasive angiography and repeat revascularization were higher after 1 year in the routine functional testing group, the formal interactions between ACS status and either invasive angiography or repeat revascularization were not significant.

Conclusion and Relevance

Despite being at higher risk for adverse clinical events in the first year after PCI than patients without ACS, patients with ACS who had undergone high-risk PCI did not derive incremental benefit from routine surveillance stress testing at 12 months compared with standard care alone during follow-up.

Trial Registration

ClinicalTrials.gov Identifier: NCT03217877.

Unravelling the progress and potential of drug-eluting stents and drug-coated balloons in cardiological insurgencies

AIM

Coronary artery disease (CAD) is the leading cause of mortality. Though percutaneous transluminal angioplasty followed by stenting is still the default treatment of choice for revascularization of obstructive CAD, the high rate of restenosis compromises the outcomes of endovascular procedures. To overcome restenosis, drug-eluting stents (DES) and drug-coated balloons (DCB) are designed that release antiproliferative drugs like sirolimus, paclitaxel, everolimus, etc., over time to inhibit cell growth and proliferation. Our review aims to summarize the challenges and progress of DES/DCBs in clinical settings.

MATERIAL AND METHODS

The comprehensive review, search and selection encompasses in relevant articles through Google Scholar, Springer online, Cochrane library and PubMed that includes research articles, reviews, letters and communications, various viewpoints, meta-analyses, randomized trials and quasi-randomized trials. Several preclinical and clinical data have been included from National Institutes of Health and clinicaltrials.gov websites.

KEY FINDINGS

Challenges like delayed endothelialization, stent thrombosis (ST), and inflammation was prominent in first-generation DES. Second-generation DES with improved designs and drug coatings enhanced biocompatibility with fewer complications. Gradual absorption of bioresorbable DES over time mitigated long-term issues associated with permanent implants. Polymer-free DES addressed the inflammation concerns but still, they leave behind metallic stents in the vasculature. As an alternative therapeutic strategy, DCB were developed to minimize inflammation in the vessel. Although both DES and DCBs have shown considerable progress, challenges persist.

SIGNIFICANCE

This review illustrates the advancements in the designs, preparation technologies, biodegradable materials, and drugs used as well as challenges associated with DES and DCBs in clinical settings.

Optimal Timing of Angiography-Guided Complete Revascularization of Non-Culprit Lesions in STEMI Patients with Multivessel Disease

Background: There are many questions regarding the optimal approach to treating non-culprit lesions in STEMI patients. Several questions still need to be answered, such as identifying the lesions to be revascularized and the optimal timing. Methods: We conducted a single-center analysis. The primary outcome was the incidence of major cardiovascular and cerebral adverse events (MACCE) at 12 months in patients with STEMI and multivessel disease (MVD) who achieved complete revascularization during the index procedure or with a staged procedure. The secondary outcomes were death from any cause, myocardial infarction, target lesion revascularization, stroke, major bleeding events, new angina episodes, new hospitalization, and in-hospital MACCE. Results: From January 2021 to December 2022, a total of 230 patients with STEMI underwent primary PCI in our department; 87 patients had MVD. Fifty-nine patients (67.8%) underwent a non-culprit revascularization strategy during the index procedure strategy, and 28 patients (32.2%) during a staged procedure. The incidence of MACCE at 12 months was 11.9% (seven patients) in the index PCI group, compared with 32.1% (nine patients) in the staged PCI group (odds ratio, 3.52; 95% CI, 1.15 to 10.77; p = 0.022). In-hospital MACCE occurred in five patients (8.5%) of the index PCI group, compared with seven patients (25%) in the staged PCI group (odds ratio, 3.60; 95% CI, 1.03 to 12.61; p = 0.036). A trend towards better outcomes favoring the index PCI group was observed with death from any cause, myocardial infarction, target lesion revascularization, and new angina episodes. Conclusions: Better outcomes were evident with an index PCI strategy than with a staged PCI strategy for complete revascularization in patients with STEMI and MVD.

Sex-related differences in coronary and carotid vessel geometry, plaque composition and shear stress obtained from imaging

Atherosclerosis manifests itself differently in men and women with respect to plaque initiation, progression and plaque composition. The observed delay in plaque progression in women is thought to be related to the hormonal status of women. Also features associated with the vulnerability of plaques to rupture seem to be less frequently present in women compared to men. Current invasive and non-invasive imaging modalities allow for visualization of plaque size, composition and high risk vulnerable plaque features. Moreover, image based modeling gives access to local shear stress and shear stress-related plaque growth. In this review, current knowledge on sex-related differences in plaque size, composition, high risk plaque features and shear stress related plaque growth in carotid and coronary arteries obtained from imaging are summarized.

Angiographic characteristics of patients with STEMI and COVID-19: Insights from NACMI registry

BACKGROUND

To date, there has been no independent core lab angiographic analysis of patients with COVID-19 and STEMI. The study characterized the angiographic parameters of patients with COVID-19 and STEMI.

METHODS

Angiograms of patients with COVID-19 and STEMI from the North American COVID-19 Myocardial Infarction (NACMI) Registry were sent to a Core Laboratory in Vancouver, Canada. Culprit lesion(s), Thrombolysis In Myocardial Infarction (TIMI) flow, Thrombus Grade Burden (TGB), and percutaneous coronary intervention (PCI) outcome were assessed.

RESULTS

From 234 patients, 74% had one culprit lesion, 14% had multiple culprits and 12% had no culprit identified. Multivessel thrombotic disease and multivessel CAD were found in 27% and 53% of patients, respectively. Stent thrombosis accounted for 12% of the presentations and occurred in 55% of patients with previous coronary stents. Of the 182 who underwent PCI, 60 (33%) had unsuccessful PCI due to post-PCI TIMI flow <3 (43/60), residual high thrombus burden (41/60) and/or thrombus related complications (27/60). In-hospital mortality for successful, partially successful, and unsuccessful PCI was 14%, 13%, and 27%, respectively. Unsuccessful PCI was associated with increased risk of in-hospital mortality (risk ratio [RR] 1.96; 95% CI: 1.05-3.66, P = .03); in the adjusted model this estimate was attenuated (RR: 1.24; 95% CI: 0.65-2.34, P = .51).

CONCLUSION

In patients with COVID-19 and STEMI, thrombus burden was pervasive with notable rates of multivessel thrombotic disease and stent thrombosis. Post-PCI, persistent thrombus and sub-optimal TIMI 3 flow rates led to one-third of the PCI's being unsuccessful, which decreased over time but remained an important predictor of in-hospital mortality.

Complete Percutaneous Coronary Revascularization in Acute Coronary Syndromes With Multivessel Coronary Disease: A Systematic Review

Multivessel disease (MVD) affects approximately 50% of patients with acute coronary syndromes (ACS) and is significantly burdened by poor outcomes and high mortality. It represents a clinical challenge in patient management and decision making and subtends an evolving research area related to the pathophysiology of unstable plaques and local or systemic inflammation. The benefits of complete revascularization are established in hemodynamically stable ACS patients with MVD, and guidelines provide some reference points to inform clinical practice, based on an evidence level that is solid for ST-segment elevation myocardial infarction and less robust for non-ST-segment elevation myocardial infarction and cardiogenic shock. However, several areas of uncertainty remain, such as the optimal timing for complete revascularization or the best guiding strategy for intermediate stenoses. We performed a systematic review of current evidence in the field of percutaneous revascularization in ACS and MVD, also including future perspectives from ongoing trials that will directly compare different timing strategies and investigate the role of invasive and noninvasive guidance techniques. (Complete percutaneous coronary revascularization in patients with acute myocardial infarction and multivessel disease; CRD42022383123).

Extent of subclinical atherosclerosis on coronary computed tomography and impact of statins in patients with diabetes without known coronary artery disease: Results from CONFIRM registry

BACKGROUND

Absence of subclinical atherosclerosis is considered safe to defer statin therapy in general population. However, impact of statins on atherosclerotic cardiovascular disease in patients with diabetes stratified by coronary artery calcium (CAC) scores and extent of non-obstructive CAD on coronary computed tomography angiography (CCTA) has not been evaluated.

METHODS

CONFIRM (Coronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multi-center Registry) study enrolled consecutive adults 18 years of age between 2005 and 2009 who underwent ³64-detector row CCTA for suspected CAD. The long-term registry includes data on 12,086 subjects who underwent CCTA at 17 centers in 9 countries. In this sub-study of CONFIRM registry, patients with diabetes mellitus (DM) and without diabetes mellitus with normal CCTA or non-obstructive plaque (<50 % diameter stenosis) for whom data on baseline statin use was available were included. CAC score was calculated using Agatston score. The magnitude of non-obstructive coronary artery disease on CCTA was quantified using segment involvement score (SIS). Primary outcome was major cardiovascular events (MACE) which included all-cause mortality, myocardial infarction, and target vessel re-vascularization.

RESULTS

A total of 7247 patients (Mean age 56.8 years) with a median follow up of 5 years were included. For DM patients, baseline statin therapy significantly reduced MACE for patients with CAC ≥100 (HR: 0.24; 95 % CI 0.07-0.87; p = 0.03) and SIS≥3 (HR: 0.23; 95 % CI 0.06-0.83; p = 0.024) compared to those not on statin therapy. Among Diabetics with lower CAC (<100) and SIS (≤3) scores, MACE was similar in statin and non-statin groups. In contrast, among non-DM patients, MACE was similar in statin and no statin groups irrespective of baseline CAC (1-99 or ≥100) and SIS.

CONCLUSION

In this large multicenter cohort of patients, the presence and extent of subclinical atherosclerosis as assessed by CAC and SIS identified patients most likely to derive benefit from statin therapy.

Compared Outcomes of ST-Elevation Myocardial Infarction Patients with Multivessel Disease Treated with Primary Percutaneous Coronary Intervention and Preserved Fractional Flow Reserve of Non-Culprit Lesions Treated Conservatively and of Those with Low Fractional Flow Reserve Managed Invasively: Insights from the FLOWER MI trial

Background: In patients with ST-elevation myocardial infarction (STEMI) and multivessel disease, percutaneous coronary intervention (PCI) for non-culprit lesions guided by FFR is superior to treatment of the culprit lesion alone. Whether deferring non-culprit PCI is safe in this specific context is questionable. We aimed to assess clinical outcomes at one-year in STEMI patients with multivessel coronary artery disease and an FFR-guided strategy for non-culprit lesions, according to whether or not ≥1 PCI was performed. Methods: Outcomes were analyzed in patients of the randomized FLOWER MI (Flow Evaluation to Guide Revascularization in Multivessel ST-Elevation Myocardial Infarction) trial in whom, after successful primary PCI, non-culprit lesions were assessed using FFR. The primary outcome was a composite of all-cause death, non-fatal MI, and unplanned hospitalization with urgent revascularization at one year. Results: Among 1,171 patients enrolled in this study, 586 were assigned to the FFR-guided group: 388 (66%) of them had ≥1 PCI and 198 (34%) had no PCI. Mean FFR before decision (i.e., PCI or not) of non-culprit lesions were 0.75±0.10 and 0.88±0.06, respectively. During follow-up, a primary outcome event occurred in 16 of 388 patients (4.1%) in patients with PCI and in 16 of 198 patients (8.1%) in patients without PCI (adjusted hazard ratio, 0.42; 95% confidence interval, 0.20 to 0.88; P = 0.02). Conclusions: In patients with STEMI undergoing complete revascularization guided by FFR measurement, those with ≥1 PCI had lower event rates at 1 year, compared with patients with deferred PCI, suggesting that deferring lesions judged relevant by visual estimation but with FFR >0.80 may not be optimal in this context. Future randomized studies are needed to confirm this data.

Virtual (Computed) Fractional Flow Reserve: Future Role in Acute Coronary Syndromes

The current management of acute coronary syndromes (ACS) is with an invasive strategy to guide treatment. However, identifying the lesions which are physiologically significant can be challenging. Non-invasive imaging is generally not appropriate or timely in the acute setting, so the decision is generally based upon visual assessment of the angiogram, supplemented in a small minority by invasive pressure wire studies using fractional flow reserve (FFR) or related indices. Whilst pressure wire usage is slowly increasing, it is not feasible in many vessels, patients and situations. Limited evidence for the use of FFR in non-ST elevation (NSTE) ACS suggests a 25% change in management, compared with traditional assessment, with a shift from more to less extensive revascularisation. Virtual (computed) FFR (vFFR), which uses a 3D model of the coronary arteries constructed from the invasive angiogram, and application of the physical laws of fluid flow, has the potential to be used more widely in this situation. It is less invasive, fast and can be integrated into catheter laboratory software. For severe lesions, or mild disease, it is probably not required, but it could improve the management of moderate disease in 'real time' for patients with non-ST elevation acute coronary syndromes (NSTE-ACS), and in bystander disease in ST elevation myocardial infarction. Its practicability and impact in the acute setting need to be tested, but the underpinning science and potential benefits for rapid and streamlined decision-making are enticing.

Intravascular Molecular Imaging: Near-Infrared Fluorescence as a New Frontier

Despite exciting advances in structural intravascular imaging [intravascular ultrasound (IVUS) and optical coherence tomography (OCT)] that have enabled partial assessment of atheroma burden and high-risk features associated with acute coronary syndromes, structural-based imaging modalities alone do not comprehensively phenotype the complex pathobiology of atherosclerosis. Near-infrared fluorescence (NIRF) is an emerging molecular intravascular imaging modality that allows for in vivo visualization of pathobiological and cellular processes at atheroma plaque level, including inflammation, oxidative stress, and abnormal endothelial permeability. Established intravascular NIRF imaging targets include macrophages, cathepsin protease activity, oxidized low-density lipoprotein and abnormal endothelial permeability. Structural and molecular intravascular imaging provide complementary information about plaque microstructure and biology. For this reason, integrated hybrid catheters that combine NIRF-IVUS or NIRF-OCT have been developed to allow co-registration of morphological and molecular processes with a single pullback, as performed for standalone IVUS or OCT. NIRF imaging is approaching application in clinical practice. This will be accelerated by the use of FDA-approved indocyanine green (ICG), which illuminates lipid- and macrophage-rich zones of permeable atheroma. The ability to comprehensively phenotype coronary pathobiology in patients will enable a deeper understanding of plaque pathobiology, improve local and patient-based risk prediction, and usher in a new era of personalized therapy.

Pancoronary Plaque Characteristics in STEMI Caused by Culprit Plaque Erosion Versus Rupture: 3-Vessel OCT Study

OBJECTIVES

This study sought to investigate nonculprit plaque characteristics in patients with ST-segment elevation myocardial infarction (STEMI) presenting with plaque erosion (PE) and plaque rupture (PR). Pancoronary vulnerability was considered at nonculprit sites: 1) the CLIMA (Relationship Between OCT Coronary Plaque Morphology and Clinical Outcome) study (NCT02883088) defined high-risk plaques with simultaneous presence of 4 optical coherence tomography (OCT) features (minimum lumen area <3.5 mm²; fibrous cap thickness [FCT] <75 μm; maximum lipid arc >180º; and macrophage accumulation); and 2) the presence of plaque ruptures or thin-cap fibroatheromas (TCFA).

BACKGROUND

PE is a unique clinical entity associated with better outcomes than PR. There is limited evidence regarding pancoronary plaque characteristics of patients with culprit PE versus culprit PR.

METHODS

Between October 2016 and September 2018, 523 patients treated by 3-vessel OCT at the time of primary percutaneous intervention were included with 152 patients excluded from final analysis.

RESULTS

Overall, 458 nonculprit plaques were identified in 202 STEMI patients with culprit PE; and 1,027 nonculprit plaques were identified in 321 STEMI patients with culprit PR. At least 1 CLIMA-defined OCT nonculprit high-risk plaque was seen in 11.4% of patients with culprit PE, but twice as many patients were seen with culprit PR (25.2%; p < 0.001). This proportion was also seen when individual high-risk features were analyzed separately. When patients with PE were divided by a heterogeneous substrate (fibrous or lipid-rich plaque) underlying the culprit site, the prevalence of nonculprits with FCT <75 μm, macrophages, and TCFA showed a significant gradient from PE_(Fibrous) to PE_{lipid-rich plaque (LRP)} to PR. Interestingly, nonculprit rupture was rarely found in patients with culprit PE_(Fibrous) (1.9%), although it was exhibited with comparable prevalence in patients with culprit PE_(LRP) (16.3%) versus PR (17.8%). Culprit PE predicted decreased pancoronary vulnerability independent of conventional risk factors.

CONCLUSIONS

STEMI patients with culprit PE have a limited pancoronary vulnerability that may explain better outcomes in these patients than in STEMI patients with culprit PR.

Management of multivessel coronary artery disease in patients with non-ST-elevation myocardial infarction: a complex path to precision medicine

Recent analyses suggest the incidence of acute coronary syndrome is declining in high- and middle-income countries. Despite this, overall rates of non-ST-elevation myocardial infarction (NSTEMI) continue to rise. Furthermore, NSTEMI is a greater contributor to mortality after hospital discharge than ST-elevation myocardial infarction (STEMI). Patients with NSTEMI are often older, comorbid and have a high likelihood of multivessel coronary artery disease (MVD), which is associated with worse clinical outcomes. Currently, optimal treatment strategies for MVD in NSTEMI are less well established than for STEMI or stable coronary artery disease. Specifically, in relation to percutaneous coronary intervention (PCI) there is a paucity of randomized, prospective data comparing multivessel and culprit lesion-only PCI. Given the heterogeneous pathological basis for NSTEMI with MVD, an approach of complete revascularization may not be appropriate or necessary in all patients. Recognizing this, this review summarizes the limited evidence base for the interventional management of non-culprit disease in NSTEMI by comparing culprit-only and multivessel PCI strategies. We then explore how a personalized, precise approach to investigation, therapy and follow up may be achieved based on patient-, disease- and lesion-specific factors.

Computed tomography coronary angiography - past, present and future

Computed tomography coronary angiography (CTCA) is a robust and reliable non-invasive alternative imaging modality to invasive coronary angiography, which is the reference standard in evaluating the degree of coronary artery stenosis. CTCA has high negative predictive value and can confidently exclude significant coronary artery disease (CAD) in low to intermediate risk patients. Over the years, substantial effort has been made to reduce the radiation dose and increase the cost efficiency of CTCA. In this review, we present the evolution of computed tomography scanners in the context of coronary artery imaging as well as its clinical applications and limitations. We also highlight the future directions of CTCA as a one-stop non-invasive imaging modality for anatomic and functional assessment of CAD.

The relationship between coronary lesion characteristics and pathologic shear in human coronary arteries

BACKGROUND

Pathological shear stress is associated with distinct pathogenic biological pathways relevant to coronary thrombosis and atherogenesis. Although the individual effects of lesion characteristics including stenosis severity, eccentricity and lesion length on coronary haemodynamics is known, their relative importance remains poorly understood.

METHODS

Computational fluid dynamics (CFD) was implemented for haemodynamic analysis of 104 coronary arteries. For each coronary artery, maximum shear stress at the site of maximal stenosis, average shear stress over the sites of maximal stenosis segment, average shear stress in the proximal segments and average shear stress in the distal segments were determined. In addition, the area of low wall shear stress (ALWSS) sites in post-stenotic regions were quantified as a proportion of the vessel segment.

RESULTS

With increasing stenosis severity, eccentricity and lesion length, maximal and average shear stress over the sites of maximal stenosis and ALWSS increased whereas average shear stress in the proximal segments decreased. Two-way ANCOVA analysis revealed that stenosis severity and lesion length were both independent predictors of maximum shear at the site of maximal stenosis [F (1, 104) = 10.94, P = 0.001 for diameter stenosis and F (1, 104) = 6.21, P = 0.014 for lesion length] and ALWSS [F (1, 104) = 66.10, P = 0.001 for diameter stenosis and F (1, 104) = 4.23, P = 0.047 for lesion length].

CONCLUSION

Our findings demonstrate that although all lesion characteristics correlate with abnormal shear stress, only stenosis severity and lesion length are independent predictors of pathogenic physiological processes.

Morphological Features and Plaque Composition in Culprit Atheromatous Plaques of Patients with Acute Coronary Syndromes

Background: The independent role of each plaque feature in relation to plaque vulnerability is still the subject of ongoing research. This study aimed to compare the morphologic characteristics of vulnerable atheromatous coronary plaques with the ones of stable, non-vulnerable plaques, and in plaques with different locations in the coronary tree, in order to identify the most relevant imaging-based biomarkers associated with coronary plaque vulnerability.

Material and methods: This was a prospective observational, non-randomized study that included 50 patients with unstable angina who underwent computed tomography angiography for assessment of the entire coronary artery tree followed by complex morphologic analysis of all lesions, divided into two groups: group 1 – 25 patients with vulnerable plaque (VP) and group 2 – 25 age- and gender-matched patients with non-vulnerable plaque (NVP).

Results: Lesions with a stenosis degree >70% were significantly longer than those with a stenosis degree <70% (8.27 ± 2.74 mm vs. 5.56 ± 4.11 mm, p = 0.04). VP presented significantly higher values of plaque thickness (p = 0.0005), plaque burden (p = 0.0004), and higher total plaque volume (p = 0.0005) than NVP. The remodeling index was not significantly different between the groups (p = 0.6), but the eccentricity index was (0.24 ± 0.14 compared to 0.14 ± 0.17, p = 0.023). Linear regression analysis revealed a significant correlation between plaque burden and plaque components in VP (r = 0.76, p <0.0001 for necrotic core; r = 0.62, p = 0.0008 for fibro-fatty tissue; and r = 0.5, p = 0.01 for fibrotic tissue volume). Culprit plaques located in the right coronary artery presented significantly larger plaque burden volumes (91.17 ± 4.88 mm3 vs. 83.35 ± 8.47 mm3, p = 0.04), larger volumes of necrotic core (82.03 ± 47.85 mm3 vs. 45.84 ± 43.72 mm3, p = 0.02) and fibrofatty tissue (53.23 ± 31.92 mm3 vs. 23.76 ± 20.90 mm3, p = 0.02) than the ones situated in the left coronary artery.

Conclusions: VPs from the culprit lesions exhibit a different phenotype than non-vulnerable ones, and vulnerability features are present in a significantly larger extent in VPs from the right coronary artery as compared to those from the left coronary artery.

Imaging of chemokine receptor CXCR4 expression in culprit and nonculprit coronary atherosclerotic plaque using motion-corrected [68Ga]pentixafor PET/CT

Purpose

The chemokine receptor CXCR4 is a promising target for molecular imaging of CXCR4⁺ cell types, e.g. inflammatory cells, in cardiovascular diseases. We speculated that a specific CXCR4 ligand, [⁶⁸Ga]pentixafor, along with novel techniques for motion correction, would facilitate the in vivo characterization of CXCR4 expression in small culprit and nonculprit coronary atherosclerotic lesions after acute myocardial infarction by motion-corrected targeted PET/CT.

Methods

CXCR4 expression was analysed ex vivo in separately obtained arterial wall specimens. [⁶⁸Ga]Pentixafor PET/CT was performed in 37 patients after stent-based reperfusion for a first acute ST-segment elevation myocardial infarction. List-mode PET data were reconstructed to five different datasets using cardiac and/or respiratory gating. Guided by CT for localization, the PET signals of culprit and various groups of nonculprit coronary lesions were analysed and compared.

Results

Ex vivo, CXCR4 was upregulated in atherosclerotic lesions, and mainly colocalized with CD68⁺ inflammatory cells. In vivo, elevated CXCR4 expression was detected in culprit and nonculprit lesions, and the strongest CXCR4 PET signal (median SUV_max 1.96; interquartile range, IQR, 1.55–2.31) was observed in culprit coronary artery lesions. Stented nonculprit lesions (median SUV_max 1.45, IQR 1.23–1.88; P = 0.048) and hot spots in naive remote coronary segments (median SUV_max 1.34, IQR 1.23–1.74; P = 0.0005) showed significantly lower levels of CXCR4 expression. Dual cardiac/respiratory gating provided the strongest CXCR4 PET signal and the highest lesion detectability.

Conclusion

We demonstrated the basic feasibility of motion-corrected targeted PET/CT imaging of CXCR4 expression in coronary artery lesions, which was triggered by vessel wall inflammation but also by stent-induced injury. This novel methodology may serve as a platform for future diagnostic and therapeutic clinical studies targeting the biology of coronary atherosclerotic plaque.

Electronic supplementary material

The online version of this article (10.1007/s00259-018-4076-2) contains supplementary material, which is available to authorized users.

Impact of Complete Revascularization on Six-Year Clinical Outcomes and Incidence of Acute Decompensated Heart Failure in Patients With ST-Segment Elevation Myocardial Infarction and Multivessel Coronary Artery Disease

It remains unclear whether complete revascularization (CR) reduces the incidences of acute decompensated heart failure (ADHF) and adverse cardiac outcomes in patients with ST-segment elevation myocardial infarction (STEMI) and multivessel coronary artery disease (MVD). A total of 453 hemodynamically stable patients with STEMI and MVD were retrospectively evaluated; the patients were divided into 2 groups according to interventional strategy: CR (n = 240) and incomplete revascularization (IR) (n = 213). We analyzed the incidences of ADHF and major adverse cardiac events (MACE; a composite of all-cause mortality, myocardial infarction, and any revascularization) over a long follow-up period (median 6.3 years). MACE developed in 158 patients (34.9%), and 40 patients (8.8%) were re-admitted because of ADHF developing during follow-up. Results after propensity matching showed that CR did not reduce the incidence of ADHF (hazard ratio [HR] for IR 1.63, 95% confidence interval [CI] 0.63 to 4.22, p = 0.311). However, IR increased the risk of MACE (HR 1.73, 95% CI 1.09 to 2.74, p = 0.021), attributable principally to an increased risk of nontarget vessel revascularization (HR 3.12, 95% CI 1.23 to 7.92, p = 0.039). Although CR did not reduce the incidence of ADHF, CR might reduce repeat revascularization to treat non-infarct-related arteries in hemodynamically stable patients with STEMI and MVD.

Nonculprit Plaque Characteristics in Patients With Acute Coronary Syndrome Caused by Plaque Erosion vs Plaque Rupture: A 3-Vessel Optical Coherence Tomography Study

Importance

Patients with culprit plaque rupture are known to have pancoronary plaque vulnerability. However, the characteristics of nonculprit plaques in patients with acute coronary syndromes caused by plaque erosion are unknown.

Objective

To investigate the nonculprit plaque phenotype in patients with acute coronary syndrome according to culprit plaque pathology (erosion vs rupture) by 3-vessel optical coherence tomography imaging.

Design, Setting, and Participants

In this observational cohort study, between August 2010 and May 2014, 82 patients with acute coronary syndrome who underwent preintervention optical coherence tomography imaging of all 3 major epicardial coronary arteries were enrolled at the Massachusetts General Hospital Optical Coherence Tomography Registry database. Analysis of the data was conducted between November 2016 and July 2017. Patients were classified into 2 groups based on the culprit lesion pathology: 17 patients with culprit plaque erosion and 34 patients with culprit plaque rupture. Thirty-one patients with the absence of culprit rupture or erosion were excluded from further analysis.

Exposures

Preintervention 3-vessel optical coherence tomography imaging.

Main Outcomes and Measures

Plaque characteristics at the culprit and nonculprit lesions evaluated by optical coherence tomography.

Results

In 51 patients (37 men; mean age, 58.7 years), the characteristics of 51 culprit plaques and 216 nonculprit plaques were analyzed. In patients with culprit erosion, the mean (SD) number of nonculprit plaques per patient was smaller (3.4 [1.9] in erosion vs 4.7 [2.1] in rupture, P = .05). Patient-based analysis showed that none of 17 patients with culprit plaque erosion had nonculprit plaque rupture, whereas 26% of the patients (9 of 34) with culprit plaque rupture had nonculprit plaque rupture (P = .02). Plaque-based analysis showed that, compared with the culprit rupture group (n = 158), the culprit erosion group (n = 58) had lower prevalence of plaque rupture (0% vs 8%; P < .001), macrophage accumulation (29% vs 53%; P = .01), microvessels (21% vs 42%; P = .003), and spotty calcium (5% vs 22%; P = .006) in the nonculprit lesions. The prevalence of lipid-rich plaque, thin-cap fibroatheroma, and thrombus did not differ between the groups.

Conclusions and Relevance

Compared with those with culprit plaque rupture, patients with acute coronary syndrome caused by culprit plaque erosion had a smaller number of nonculprit plaques and the lower levels of panvascular instability, affirming that distinct pathophysiologic mechanisms operate in plaque erosion and plaque rupture.

From vulnerable plaque to blood healthy therapy

Cardiovascular atherosclerotic disease is the leading cause of death in China and in Western nations. People with plaque or stenosis in the coronary artery or the carotid artery are the most susceptible population to suffer from acute events. Current investigations showed that plaque with the characteristics of intra-plaque hemorrhage or a thin cap with a large lipid core was causally associated with vulnerable plaque and plaque rupture. Of the many plaque ruptures occurring in patients with atherosclerotic disease, very few will trigger symptomatic events, rendering it exceedingly difficult to predict adverse outcomes. The assumption that identifying lesions prone to rupture will prevent acute coronary events was unrealistic. Factors in blood, especially those risk factors associated with thrombosis, play an important role as a bridge between plaque rupture and subsequent clinical events. Since there is little management to efficiently decrease the frequency of plaque rupture or erosion, blood healthy therapy, as a therapeutic apheresis to decrease the blood hypercoagulability to modulate the blood to be thrombosis resisting, should be considered as a potential therapeutic approach to reducing the incidence of acute coronary syndrome and stroke.

Intravascular imaging in coronary artery disease

Although it is the method used by most interventional cardiologists to assess the severity of coronary artery disease and guide treatment, coronary angiography has many known limitations, particularly the fact that it is a lumenogram depicting foreshortened, shadowgraph, planar projections of the contrast-filled lumen rather than imaging the diseased vessel itself. Intravascular imaging-intravascular ultrasound and more recently optical coherence tomography-provide a tomographical or cross-sectional image of the coronary arteries. These techniques are clinically useful to answer questions such as whether the stenosis is clinically relevant; the identification of the culprit lesion; or whether the plaque (or patient) is at high risk of future adverse events. They can also be used to optimise stent implantation to minimise stent-related adverse events, provide answers to the likelihood of distal embolisation or peri-procedural myocardial infarction during stent implantation, and provide reasons for stent thrombosis or restenosis. This review considers the usefulness of intravascular imaging in day-to-day practice.

Interactions Between Reciprocal ST-Segment Downsloping During ST-Elevated Myocardial Infarction and Global Cardiac Perfusion and Functional Abnormalities

Reciprocal ST-segment downsloping on electrocardiogram is a frequent finding during ST-elevated myocardial infarction (STEMI), but its etiology is still disputed. We sought to evaluate the relation between reciprocal ST-segment downsloping during STEMI and major cardiac perfusion and functional parameters. One hundred eighty-five patients with STEMI underwent emergency coronary angiography. The presence of reciprocal ST-segment downsloping was assessed. At coronary angiography, the corrected TIMI frame count (cTFC) was computed both on culprit and remote vessels and the occurrence of "no/slow reflow" phenomenon after percutaneous coronary intervention (PCI) identified. The left ventricular wall motion score index ratio (discharge/admission values) at echocardiography and the slope of high-sensitivity troponin elimination were computed as measures of effective myocardial reperfusion. Reciprocal ST-segment downsloping was revealed in 91 patients (49%). They presented higher cTFC values on remote vessels than patients without reciprocal electrocardiographic abnormalities (44 ± 18 vs 37 ± 15 cineframes × second^-1, p = 0.004). The presence of remote ST-segment downsloping was also associated with a higher prevalence of "no/slow reflow" phenomenon (59% vs 40%, p = 0.013) as well as more abnormal values of wall motion score index ratio (p = 0.042) and high-sensitivity troponin slope (p = 0.012). At multivariate analyses, a higher cTFC on remote vessels predicted the occurrence of reciprocal ST-segment changes (p = 0.018) and the development of "no/slow reflow" phenomenon after PCI (p = 0.005). In conclusion, the presence of reciprocal ST-segment downsloping during STEMI clusters with significant perfusion and cardiac functional abnormalities, predicting the development of "no reflow" phenomenon after PCI.

Photodynamic therapy for the treatment of atherosclerotic plaque: Lost in translation?

Acute coronary syndrome is a life-threatening condition of utmost clinical importance, which, despite recent progress in the field, is still associated with high morbidity and mortality. Acute coronary syndrome results from a rupture or erosion of vulnerable atherosclerotic plaque with secondary platelet activation and thrombus formation, which leads to partial or complete luminal obstruction of a coronary artery. During the last decade, scientific evidence demonstrated that when an acute coronary event occurs, several nonculprit plaques are in a "vulnerable" state. Among the promising approaches, several investigations provided evidence of photodynamic therapy (PDT)-induced stabilization and regression of atherosclerotic plaque. Significant development of PDT strategies improved its therapeutic outcome. This review addresses PDT's pertinence and major problems/challenges toward its translation to a clinical reality.

Assessment of Coronary Plaque Vulnerability in Acute Coronary Syndromes using Optical Coherence Tomography and Intravascular Ultrasound. A Systematic Review

The aim of this systematic review was to analyze studies characterizing vulnerable coronary plaques using optical coherence tomography (OCT) and intravascular ultrasound (IVUS), in order to identify the most efficient invasive technique permitting plaque characterization in patients with acute myocardial infarction.

Method: A total number of 432 studies were identified, 420 through database searching and 12 through manual searching. Eight duplicate studies were removed, leaving a total number of 424 studies to be screened. Twenty-six studies only available in Abstract-only form were excluded, resulting in 398 studies checked for eligibility. Eleven studies fulfilled the eligibility criteria and were included in this systematic analysis. Plaque vulnerability was investigated in plaques with thin cap fibroatheroma (TCFA) versus those with thick cap fibroatheroma, in ruptured coronary plaques versus non-ruptured coronary plaques, in culprit versus non-culprit lesions and in lipid-rich versus non-lipid-rich plaques.

Results: A total of 1,568 coronary plaques in 1,225 patients with acute coronary syndromes (ACS) who underwent both IVUS and OCT for analysis of plaque features were included in the final analysis. The review identified the following IVUS-derived features as significantly correlated with plaque vulnerability: plaque burden (p <0.001), remodeling index (p <0.001), external elastic membrane cross-sectional area (p <0.001), and the amount of necrotic core (p <0.001), while OCT-derived features characterizing unstable plaque were TCFA (p <0.001), lipid arch (p <0.001), accumulation of macrophages (p = 0.03), and presence of intracoronary thrombus (p <0.001).

Conclusion: Both IVUS and OCT are invasive imaging techniques able to provide relevant information on the vulnerability of coronary atheromatous plaques, identifying, as they do, various plaque features significantly associated with unstable plaques. Information provided by the two techniques is complementary, and both methods can serve as a useful clinical diagnostic tool, especially in cases of ACS patients undergoing a revascularization procedure.

Impact of Longitudinal Lesion Geometry on Location of Plaque Rupture and Clinical Presentations

OBJECTIVES

This study sought to investigate the impact of longitudinal lesion geometry on the location of plaque rupture and clinical presentation and its mechanism.

BACKGROUND

The relationships among lesion geometry, external hemodynamic forces acting on the plaque, location of plaque rupture, and clinical presentation have not been comprehensively investigated.

METHODS

This study enrolled 125 patients with plaque rupture documented by intravascular ultrasound. Longitudinal locations of plaque rupture were identified and categorized by intravascular ultrasound. Patients' clinical presentations and TIMI (Thrombolysis In Myocardial Infarction) flow grade in an initial angiogram were compared according to the location of plaque rupture. Longitudinal lesion asymmetry was quantitatively assessed by the luminal radius change over the segment length (radius gradient [RG]). Lesions with a steeper radius change in the upstream segment compared with the downstream segment (RG_upstream > RG_downstream) were defined as upstream-dominant lesions.

RESULTS

On the basis of the site of maximum rupture aperture, 56.0%, 16.0%, and 28.0% of the patients had upstream, minimal lumen area, and downstream rupture, respectively. Patients with upstream rupture more frequently presented with ST-segment elevation myocardial infarction (45.7%, 40.0%, 22.9%; p = 0.030) and with TIMI flow grade <3 (32.9%, 20.0%, 17.1%; p = 0.042). According to the ratio of upstream and downstream RG, 69.5% of lesions were classified as upstream-dominant lesions, and 30.5% were classified as downstream-dominant lesions. Among the 66 upstream-dominant lesions, 65 cases (98.5%) had upstream rupture, and the RG ratio (RG_upstream/RG_downstream) was an independent predictor of upstream rupture (odds ratio: 1.481; 95% confidence interval: 1.035 to 2.120; p = 0.032). Upstream-dominant lesions more frequently manifested with ST-segment elevation myocardial infarction than did downstream-dominant lesions (48.5% vs. 24.1%; p = 0.026).

CONCLUSIONS

Both clinical presentation and degree of flow limitation were associated with the location of plaque rupture. Longitudinal lesion asymmetry assessed by RG, which can affect regional distribution of hemodynamic stress, was associated with the location of rupture and with clinical presentation.

Prevalence and Predictors of Multiple Coronary Plaque Ruptures: In Vivo 3-Vessel Optical Coherence Tomography Imaging Study

OBJECTIVE

Plaque rupture may be the local expression of a widespread coronary instability. This study aimed to investigate: (1) the prevalence and characteristics of nonculprit plaque rupture; (2) the pancoronary atherosclerotic phenotype in patients with and without nonculprit plaque rupture; and (3) the prevalence and predictors of multiple plaque ruptures.

APPROACH AND RESULTS

Six hundred and seventy-five nonculprit plaques from 261 patients (34 acute myocardial infarction, 73 unstable angina pectoris, and 154 stable angina pectoris) were analyzed by 3-vessel optical coherence tomography. Nonculprit plaque ruptures were identified in 51 patients (20%). Patients with nonculprit plaque ruptures had higher prevalence of thin-cap fibroatheroma (51% versus 13%; P<0.001) in the 3 major epicardial coronary vessels. Multiple plaque ruptures were observed in 20% of patients (38% acute myocardial infarction versus 10% unstable angina pectoris versus 19% stable angina pectoris; P=0.042). Thin-cap fibroatheroma, intimal vasculature, and macrophages were independent morphological predictors of multiple plaque ruptures, whereas acute myocardial infarction and chronic kidney disease were independent clinical predictors. Patients with nonculprit plaque ruptures showed higher 1-year rates of nontarget lesion revascularization (11.8% versus 4.4%; P=0.039).

CONCLUSIONS

Nonculprit plaque ruptures were observed in 20% of patients with coronary artery disease and were associated with pancoronary vulnerability and higher 1-year revascularization rate.

The Spatial Distribution of Plaque Vulnerabilities in Patients with Acute Myocardial Infarction

Objective

Although the plaque characteristics have been recognized in patients with acute myocardial infarction (AMI), the plaque spatial distribution is not well clarified. Using color-mapping intravascular ultrasound (iMAP-IVUS), we examined culprit lesions to clarify plaque morphology, composition and spatial distribution of the sites of potential vulnerability.

Methods

Sixty-eight culprit lesions in 64 consecutive AMI patients who underwent angiography and IVUS examinations before intervention were analyzed. Plaque morphology and composition were quantified with iMAP-IVUS. The spatial distribution of the sites of potential vulnerability was assessed with longitudinal reconstruction of the consecutive IVUS images. The plaque characteristics were also compared between ruptured and non-ruptured lesions, and between totally occlusive (TO) and non-TO lesions.

Results

The sites with maximum necrotic area (maxNA), maximum plaque burden (maxPB) and most severely narrowed (minimal luminal area, MLA) were recognized vulnerability. In the majority of cases, maxNA sites were proximal to the maxPB sites, and MLA sites were distal to the maxNA and maxPB sites. Ruptures usually occurred close to maxNA sites and proximal to maxPB and MLA sites. The average distance from the site of rupture to the maxNA site was 0.33 ± 4.04 mm. Ruptured lesions showed significant vessel remodeling, greater plaque volume, and greater lipidic volume compared to those of non-ruptured lesions. Both the length and plaque burden (PB) of TO lesions were greater than those of non-TO lesions.

Conclusions

Instead of overlapping on maxPB sites, most maxNA sites are proximal to the maxPB sites and are the sites most likely to rupture. Plaque morphology and composition play critical roles in plaque rupture and coronary occlusion.

Defining the non-vulnerable and vulnerable patients with computed tomography coronary angiography: evaluation of atherosclerotic plaque burden and composition

The shift from coronary plaque stability to plaque instability remains poorly understood despite enormous efforts and expenditures have been assigned to the study of the subject. On the other hand, there have been serious advances in imaging helping us to characterizenon-vulnerable patients The latter has much more value in the clinical decision-making process since it provides high certainty that the patient's probability of a future acute event is low and treatment decisions should be made accordingly. Although coronary plaque rupture is still recognized as the main source of acute thrombotic events, numerous studies have shown that the prediction of events on an individual basis is far more complex and demands a more open approach aimed at characterizing patient risk rather than assessing the risk of thrombosis of a single plaque. Computed tomography coronary angiography (CTCA) has the ability to evaluate non-invasively the extent, burden, severity, and characteristics of coronary artery disease (CAD) and has a close relationship to intravascular ultrasound. On the basis of an excellent negative predictive value with an annualized event rate of ∼0.20% assessed over more than 6000 patients, thus providing a 5-year warranty period, CTCA has been identified as the finest non-invasive tool to exclude CAD. This means that CTCA is able to reliably characterize the non-vulnerable patient. Conversely, in the past few years, several studies have attempted to establish CTCA-derived predictors of acute coronary syndromes, both from a lesion level and a patient level basis with very low positive predictive value, thus questioning the vulnerable patient/plaque concept.

Usefulness of Coronary Atheroma Burden to Predict Cardiovascular Events in Patients Presenting With Acute Coronary Syndromes (from the PROSPECT Study)

We investigated the relation between overall atheroma burden and clinical events in the Providing Regional Observations to Study Predictors of Events in the Coronary Tree (PROSPECT) study. In PROSPECT, 660 patients (3,229 nonculprit lesions with a plaque burden ≥ 40% and complete intravascular ultrasound data) were divided into tertiles according to baseline percent atheroma volume (PAV: total plaque/vessel volume). Patients were followed for 3.4 years (median); major adverse cardiac events (MACE: death from cardiac causes, cardiac arrest, myocardial infarction, or rehospitalization because of unstable or progressive angina) were adjudicated to either culprit or nonculprit lesions. Compared with patients in low or intermediate PAV tertiles, patients in the high PAV tertile had the greatest prevalence of plaque rupture and radiofrequency thin-cap fibroatheroma (VH-TCFA) and the highest percentage of necrotic core volume; they were also more likely to have high-risk lesion characteristics: ≥ 1 lesion with minimal luminal area ≤ 4 mm(2), plaque burden >70%, and/or VH-TCFA. Three-year cumulative nonculprit lesion-related MACE was greater in the intermediate and high tertiles than in the low tertile (6.3% vs 14.7% vs 15.1%, low vs intermediate vs high tertiles, p = 0.009). On Cox multivariable analysis, insulin-dependent diabetes (hazard ratio [HR] 3.98, p = 0.002), PAV (HR 1.06, p = 0.03), and the presence of ≥1 VH-TCFA (HR 1.80, p = 0.02) were independent predictors of nonculprit MACE. In conclusion, increasing baseline overall atheroma burden was associated with more advanced, complex, and vulnerable intravascular ultrasound lesion morphology and independently predicted nonculprit lesion-related MACE in patients with acute coronary syndromes after successful culprit lesion intervention.

Computerized methodology for micro-CT and histological data inflation using an IVUS based translation map

A framework for the inflation of micro-CT and histology data using intravascular ultrasound (IVUS) images, is presented. The proposed methodology consists of three steps. In the first step the micro-CT/histological images are manually co-registered with IVUS by experts using fiducial points as landmarks. In the second step the lumen of both the micro-CT/histological images and IVUS images are automatically segmented. Finally, in the third step the micro-CT/histological images are inflated by applying a transformation method on each image. The transformation method is based on the IVUS and micro-CT/histological contour difference. In order to validate the proposed image inflation methodology, plaque areas in the inflated micro-CT and histological images are compared with the ones in the IVUS images. The proposed methodology for inflating micro-CT/histological images increases the sensitivity of plaque area matching between the inflated and the IVUS images (7% and 22% in histological and micro-CT images, respectively).

Plaque rupture and intact fibrous cap assessed by optical coherence tomography portend different outcomes in patients with acute coronary syndrome

AIMS

Patients presenting with acute coronary syndrome (ACS) may have different plaque morphologies at the culprit lesion. In particular, plaque rupture (PR) has been shown as the more frequent culprit plaque morphology in ACS. However, its prognostic value is still unknown. In this study, we evaluated the prognostic value of PR, compared with intact fibrous cap (IFC), in patients with ACS.

METHODS AND RESULTS

We enrolled consecutive patients admitted to our Coronary Care Unit for ACS and undergoing coronary angiography followed by interpretable optical coherence tomography (OCT) imaging. Culprit lesion was classified as PR and IFC by OCT criteria. Prognosis was assessed according to such culprit lesion classification. Major adverse cardiac events (MACEs) were defined as the composite of cardiac death, non-fatal myocardial infarction, unstable angina, and target lesion revascularization (follow-up mean time 31.58 ± 4.69 months). The study comprised 139 consecutive ACS patients (mean age 64.3 ± 12.0 years, male 73.4%, 92 patients with non-ST elevation ACS and 47 with ST-elevation ACS). Plaque rupture was detected in 82/139 (59%) patients. There were no differences in clinical, angiographic, or procedural data between patients with PR when compared with those having IFC. Major adverse cardiac events occurred more frequently in patients with PR when compared with those having IFC (39.0 vs. 14.0%, P = 0.001). Plaque rupture was an independent predictor of outcome at multivariable analysis (odds ratio 3.735, confidence interval 1.358-9.735).

CONCLUSION

Patients with ACS presenting with PR as culprit lesion by OCT have a worse prognosis compared with that of patients with IFC. This finding should be taken into account in risk stratification and management of patients with ACS.

Focal association between wall shear stress and clinical coronary artery disease progression

Wall shear stress (WSS) has been investigated as a potential prospective marker to identify rapidly progressing coronary artery disease (CAD) and potential for lesions to acquire vulnerable characteristics. Previous investigations, however, are limited by a lack of understanding of the focal association between WSS and CAD progression (i.e., data are notably spatially averaged). Thus, the aim of this investigation was to examine the focal association between WSS and coronary atherosclerosis progression, and compare these results to those determined by spatial averaging. Five patients with CAD underwent baseline and 6-month follow-up angiographic and virtual histology-intravascular ultrasound imaging to quantify CAD progression. Patient-specific computational fluid dynamics models were constructed to compute baseline WSS values, which were either averaged around the entire artery circumference or examined in focal regions (sectors). Analysis of data within each sector (n = 3871) indicated that circumferentially averaged and sector WSS values were statistically different (p < 0.05) and exhibited poor agreement (concordance correlation coefficient = 0.69). Furthermore, differences were observed between the analysis techniques when examining the association of WSS and CAD progression. This investigation highlights the importance of examining spatially heterogeneous variables at a focal level to reduce the affect of data reduction and warrants implementation in a larger clinical study to determine the predictive power in prospectively identifying rapidly progressing and/or vulnerable coronary plaques.

IVUS-based FSI models for human coronary plaque progression study: components, correlation and predictive analysis

Atherosclerotic plaque progression is believed to be associated with mechanical stress conditions. Patient follow-up in vivo intravascular ultrasound coronary plaque data were acquired to construct fluid-structure interaction (FSI) models with cyclic bending to obtain flow wall shear stress (WSS), plaque wall stress (PWS) and strain (PWSn) data and investigate correlations between plaque progression measured by wall thickness increase (WTI), cap thickness increase (CTI), lipid depth increase (LDI) and risk factors including wall thickness (WT), WSS, PWS, and PWSn. Quarter average values (n = 178-1016) of morphological and mechanical factors from all slices were obtained for analysis. A predictive method was introduced to assess prediction accuracy of risk factors and identify the optimal predictor(s) for plaque progression. A combination of WT and PWS was identified as the best predictor for plaque progression measured by WTI. Plaque WT had best overall correlation with WTI (r = -0.7363, p < 1E-10), cap thickness (r = 0.4541, p < 1E-10), CTI (r = -0.4217, p < 1E-8), LD (r = 0.4160, p < 1E-10), and LDI (r = -0.4491, p < 1E-10), followed by PWS (with WTI: (r = -0.3208, p < 1E-10); cap thickness: (r = 0.4541, p < 1E-10); CTI: (r = -0.1719, p = 0.0190); LD: (r = -0.2206, p < 1E-10); LDI: r = 0.1775, p < 0.0001). WSS had mixed correlation results.

Impact of Intravascular Ultrasound in Clinical Practice

Intravascular ultrasound (IVUS) has expanded our understanding of atherosclerotic plaque morphology, and provides an opportunity to guide cardiovascular interventions and evaluate results. Use of this technique requires understanding of ultrasound physics, catheter differences, skills in vessel, plaque and stent quantification and knowledge of artifacts and various physiologic and pathologic findings. Optimal cardiovascular interventions should result in absence of inflow or outflow obstruction, precise geographic landing, while attaining the largest feasible luminal gain without plaque protrusion, vessel dissection or perforation and, if deployed, with complete stent expansion and apposition to the vessel wall. IVUS is safe, cost efficient and effectively optimises cardiovascular interventions. In addition, IVUS improves outcomes when used to guide coronary interventions using bare metal stents (BMS) and drug eluting stents (DES). The role of IVUS in endovascular therapy is rapidly expanding. This review will focus on the impact of IVUS in clinical practice.