Plaque morphologies and the clinical prognosis of acute coronary syndrome caused by lesions with intact fibrous cap diagnosed by optical coherence tomography

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.

Atherosclerotic Autoantigen ALDH4A1 as a Novel Immunological Indicator for Plaque Erosion in Patients with ST Segment Elevated Myocardial Infarction

OBJECTIVE

 Aldehyde dehydrogenase 4A1 (ALDH4A1) was recently reported to be a novel autoantigen of atherosclerosis. However, its role in different phenotypes of acute coronary syndrome remains unclear. Herein, we planned to explore the circulating and regional expression of ALDH4A1 in patients with plaque rupture (PR) and plaque erosion (PE) determined by optical coherence tomography (OCT).

METHODS AND RESULTS

 After applying the inclusion and exclusion criteria, a prospective series of 312 patients with ST segment elevated myocardial infarction (STEMI), including 161 patients with PR and 151 patients with PE determined by OCT, were enrolled for plasma ALDH4A1 testing. In addition, ALDH4A1 was quantified using immunofluorescence in aspirated coronary thrombus samples obtained from 31 patients with PR and 25 patients with PE. In addition, we established an atherosclerosis mouse model and analyzed the distribution of ALDH4A1 expression in different mouse organs. Furthermore, we compared the level of ALDH4A1 in the spleen and carotid artery between Apoe-/- and C57 mice. The results showed that the plasma level of ALDH4A1 was significantly higher in STEMI patients with PE than in those with PR (4.6 ng/mL [2.2-8.7] vs. 3.5 ng/mL [1.6-5.6] p = 0.005). The expression of ALDH4A1 in aspirated coronary thrombi was also significantly higher in patients with PE than in those with PR (mean gray value: 32.0 [23.6-40.6] vs. 16.8 [14.0-24.5], p < 0.001). In animal models, the expression of ALDH4A1 is much higher in the spleen than in other organs, and the level of ALDH4A1 is significantly elevated in the spleen and carotid artery of Apoe-/- mice compared with C57 mice.

CONCLUSION

 The high levels of ALDH4A1 in the plasma and aspirated coronary thrombi independently correlated with PE in patients with STEMI. These results suggested that ALDH4A1 is involved in the mechanism of PE and serves as a promising biomarker and treatment target for patients with PE.

Optical coherence tomography (OCT) - versus angiography-guided strategy for percutaneous coronary intervention: a meta-analysis of randomized trials

BACKGROUND

Optical coherence tomography (OCT) guidance in percutaneous coronary intervention (PCI) has been shown to improve procedural outcomes. However, evidence supporting its superiority over angiography-guided PCI in terms of clinical outcomes is still emerging and limited. This study aimed to compare the efficacy and safety of OCT-guided PCI versus angiography-guided PCI in patients with coronary artery disease (CAD).

METHODS

A systematic search of electronic databases was conducted to identify randomized control trials (RCTs) comparing the clinical outcomes of OCT-guided and angiography-guided PCI in patients with CAD. Clinical endpoints including all-cause mortality, myocardial infarction (MI), target lesion revascularization (TLR), stent thrombosis and major adverse cardiac events (MACE) were assessed.

RESULTS

Eleven RCTs, comprising 2,699 patients in the OCT-guided group and 2,968 patients in the angiography-guided group met inclusion criteria. OCT-guided PCI was associated with significantly lower rates of cardiovascular death(RR 0.56; 95%CI: 0.32-0.98; p = 0.04; I2 = 0%), stent thrombosis(RR 0.56; 95%CI: 0.33-0.95; p = 0.03; I2 = 0%), and MACE (RR 0.79; 95%CI: 0.66-0.95; p = 0.01; I2 = 5%). The incidence of all-cause death (RR 0.71; 95%CI: 0.49-1.02; p = 0.06; I2 = 0%), myocardial infarction (RR 0.86; 95%CI: 0.67-1.10; p = 0.22; I2 = 0%) and TLR (RR 0.98; 95%CI: 0.73-1.33; p = 0.91; I2 = 0%) was non-significantly lower in the OCT-guided group.

CONCLUSIONS

Among patients undergoing PCI, OCT-guided PCI was associated with lower incidences of cardiovascular death, stent thrombosis and MACE compared to angiography-guided PCI.

TRIAL REGISTRATION

PROSPERO registration number: CRD42023484342.

Diagnosis and Prognostic Value of the Underlying Cause of Acute Coronary Syndrome in Optical Coherence Tomography-Guided Emergency Percutaneous Coronary Intervention

Background The prognostic impact of optical coherence tomography-diagnosed culprit lesion morphology in acute coronary syndrome (ACS) has not been systematically examined in real-world settings. Methods and Results This investigator-initiated, prospective, multicenter, observational study was conducted at 22 Japanese hospitals to identify the prevalence of underlying ACS causes (plaque rupture [PR], plaque erosion [PE], and calcified nodules [CN]) and their impact on clinical outcomes. Patients with ACS diagnosed within 24 hours of symptom onset undergoing emergency percutaneous coronary intervention were enrolled. Optical coherence tomography-guided percutaneous coronary intervention recipients were assessed for underlying ACS causes and followed up for major adverse cardiac events (cardiovascular death, myocardial infarction, heart failure, or ischemia-driven revascularization) at 1 year. Of 1702 patients with ACS, 702 (40.7%) underwent optical coherence tomography-guided percutaneous coronary intervention for analysis. PR, PE, and CN prevalence was 59.1%, 25.6%, and 4.0%, respectively. One-year major adverse cardiac events occurred most frequently in patients with CN (32.1%), followed by PR (12.4%) and PE (6.2%) (log-rank P<0.0001), primarily driven by increased cardiovascular death (CN, 25.0%; PR, 0.7%; PE, 1.1%; log-rank P<0.0001) and heart failure trend (CN, 7.1%; PR, 6.8%; PE, 2.2%; log-rank P<0.075). On multivariate Cox regression analysis, the underlying ACS cause was associated with 1-year major adverse cardiac events (CN [hazard ratio (HR), 4.49 [95% CI, 1.35-14.89], P=0.014]; PR (HR, 2.18 [95% CI, 1.05-4.53], P=0.036]; PE as reference). Conclusions Despite being the least common, CN was a clinically significant underlying ACS cause, associated with the highest future major adverse cardiac events risk, followed by PR and PE. Future studies should evaluate the possibility of ACS underlying cause-based optical coherence tomography-guided optimization.

Culprit plaque morphology determines inflammatory risk and clinical outcomes in acute coronary syndrome

AIMS

Rupture of the fibrous cap (RFC) and erosion of an intact fibrous cap (IFC) are the two predominant mechanisms causing acute coronary syndromes (ACS). It is uncertain whether clinical outcomes are different following RFC-ACS vs. IFC-ACS and whether this is affected by a specific inflammatory response. The prospective, translational OPTIcal-COherence Tomography in Acute Coronary Syndrome study programme investigates the impact of the culprit lesion phenotype on inflammatory profiles and prognosis in ACS patients.

METHODS AND RESULTS

This analysis included 398 consecutive ACS patients, of which 62% had RFC-ACS and 25% had IFC-ACS. The primary endpoint was a composite of cardiac death, recurrent ACS, hospitalization for unstable angina, and target vessel revascularization at 2 years [major adverse cardiovascular events (MACE+)]. Inflammatory profiling was performed at baseline and after 90 days. Patients with IFC-ACS had lower rates of MACE+ than those with RFC-ACS (14.3% vs. 26.7%, P = 0.02). In 368-plex proteomic analyses, patients with IFC-ACS showed lower inflammatory proteome expression compared with those with RFC-ACS, including interleukin-6 and proteins associated with the response to interleukin-1β. Circulating plasma levels of interleukin-1β decreased from baseline to 3 months following IFC-ACS (P < 0.001) but remained stable following RFC-ACS (P = 0.25). Interleukin-6 levels decreased in patients with RFC-ACS free of MACE+ (P = 0.01) but persisted high in those with MACE+.

CONCLUSION

This study demonstrates a distinct inflammatory response and a lower risk of MACE+ following IFC-ACS. These findings advance our understanding of inflammatory cascades associated with different mechanisms of plaque disruption and provide hypothesis generating data for personalized anti-inflammatory therapeutic allocation to ACS patients, a strategy that merits evaluation in future clinical trials.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction: Rationale and Design of the ATLAS-OCT Study

Even after successful revascularization with primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI), subsequent adverse events still occur. Previous studies have suggested potential benefits of intravascular imaging, including optical coherence tomography (OCT). However, the feasibility of OCT-guided primary PCI has not been systematically examined in these patients. The ATLAS-OCT (ST-elevation Acute myocardial infarcTion and cLinicAl outcomeS treated by Optical Coherence Tomography-guided percutaneous coronary intervention) trial was designed to investigate the feasibility of OCT guidance during primary PCI for STEMI in experienced centers with expertise on OCT-guided PCI as a prospective, multicenter registry of consecutive patients with STEMI who underwent a primary PCI. The sites' inclusion criteria are as follows: (1) acute care hospitals providing 24/7 emergency care for STEMI, and (2) institutions where OCT-guided PCI is the first choice for primary PCI in STEMI. All patients with STEMI who underwent primary PCI at participating sites will be consecutively enrolled, irrespective of OCT use during PCI. The primary end point will be the rate of successful OCT imaging during the primary PCI. As an ancillary imaging modality to angiography, OCT provides morphologic information during PCI for the assessment of plaque phenotypes, vessel sizing, and PCI optimization. Major adverse cardiac events, defined as a composite of all-cause death, myocardial infarction, and target vessel revascularization at 1 year, will also be recorded. The ATLAS-OCT study will clarify the feasibility of OCT-guided primary PCI for patients with STEMI and further identify a suitable patient group for OCT-guided primary PCI.

Clinical impact of optical coherence tomography findings after drug-coated balloon treatment for patients with acute coronary syndromes

BACKGROUND

Drug-coated balloon (DCB) became a potential treatment option for patients with acute coronary syndrome (ACS); however, factors associated with target lesion failure (TLF) remain uncertain.

METHODS

This retrospective, multicentre, observational study included consecutive ACS patients who underwent optical coherence tomography (OCT)-guided DCB treatment. Patients were divided into two groups according to the occurrence of TLF, a composite of cardiac death, target vessel-related myocardial infarction, and ischemia-driven target lesion revascularisation.

RESULTS

We enrolled 127 patients in this study. During the median follow-up period of 562 (IQR: 342-1164) days, 24 patients (18.9%) experienced TLF, and 103 patients (81.1%) did not. The cumulative 3-year incidence of TLF was 22.0%. The cumulative 3-year incidence of TLF was the lowest in patients with plaque erosion (PE) (7.5%), followed by those with rupture (PR) (26.1%) and calcified nodule (CN) (43.5%). Multivariable Cox regression analysis revealed that plaque morphology was independently associated with TLF on pre-PCI (percutaneous coronary intervention) OCT, and residual thrombus burden (TB) was positively associated with TLF on post-PCI OCT. Further stratification by post-PCI TB revealed a comparable incidence of TLF in patients with PR (4.2%) to that of PE if the culprit lesion had a smaller post-PCI TB than the cut-off value (8.4%). TLF incidence was high in patients with CN, regardless of TB size on post-PCI OCT.

CONCLUSIONS

Plaque morphology was strongly associated with TLF for ACS patients after DCB treatment. Residual TB post-PCI might be a key determinant for TLF, especially in patients with PR.

Clinical outcomes of acute myocardial infarction arising from non-lipid-rich plaque determined by NIRS-IVUS

Acute myocardial infarction (AMI) can rarely arise from non-lipid-rich coronary plaques. This study sought to compare the clinical outcomes after percutaneous coronary intervention (PCI) between AMI showing maximum lipid-core burden index in 4 mm (maxLCBI_4mm) < 400 and ≥ 400 in the infarct-related lesions assessed by near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS). We investigated 426 AMI patients who underwent NIRS-IVUS in the infarct-related lesions before PCI. Major adverse cardiovascular events (MACE) were defined as the composite of cardiac death, non-fatal MI, clinically driven target lesion revascularization (TLR), clinically driven non-TLR, and congestive heart failure requiring hospitalization. 107 (25%) patients had infarct-related lesions of maxLCBI_4mm < 400, and 319 (75%) patients had those of maxLCBI_4mm ≥ 400. The maxLCBI_4mm < 400 group had a younger median age at onset (68 years [IQR: 57-78 years] vs. 73 years [IQR: 64-80 years], P = 0.007), less frequent multivessel disease (39% vs. 51%, P = 0.029), less frequent TIMI flow grade 0 or 1 before PCI (62% vs. 75%, P = 0.007), and less frequent no-reflow immediately after PCI (5% vs. 11%, P = 0.039). During a median follow-up period of 31 months [IQR: 19-48 months], the frequency of MACE was significantly lower in the maxLCBI_4mm < 400 group compared with the maxLCBI_4mm ≥ 400 group (4.7% vs. 17.2%, P = 0.001). MaxLCBI_4mm < 400 was an independent predictor of MACE-free survival at multivariable analysis (hazard ratio: 0.36 [confidence interval: 0.13-0.98], P = 0.046). MaxLCBI_4mm < 400 measured by NIRS in the infract-related lesions before PCI was associated with better long-term clinical outcomes in AMI patients.

Optical Coherence Tomography in Vulnerable Plaque and Acute Coronary Syndrome

Optical coherence tomography (OCT) is an intravascular imaging technique that uses near-infrared light. OCT provides high-resolution cross-sectional images of coronary arteries and enables tissue characterization of atherosclerotic plaques. OCT can identify plaque rupture, plaque erosion, and calcified nodule in culprit lesions of acute coronary syndrome. OCT can also detect important morphologic features of vulnerable plaques such as thin fibrous caps, large lipid cores, macrophages accumulation, intraplaque microvasculature, cholesterol crystals, healed plaques, and intraplaque hemorrhage.

Sex-specific Inequalities in the Treatment of Severely Calcified Coronary Lesions: A Sub-analysis of the PREPARE-CALC Trial

Background: Coronary vessels in women may have anatomical and histological particularities. The aim of this study was to investigate sex-specific characteristics and outcomes of patients with calcified coronary arteries in the Prepare-CALC (Comparison of Strategies to Prepare Severely Calcified Coronary Lesions) trial. Methods: The Prepare-CALC trial randomised patients with severe coronary calcification to coronary lesion preparation either using modified balloons (MB; cutting or scoring) or rotational atherectomy (RA). Results: Of 200 randomised patients, 24% were women. Strategy success in general was similar between women (93.8%) and men (88.2%; p=0.27). For men, strategy success was significantly more common with an RA-based strategy than an MB-based strategy (98.7% in the RA group versus 77.3% in the MB group, p<0.001), whereas for women there was no evidence of a significant difference in strategy success between RA and MB (95.7% in the RA group versus 92% in the MB group, p>0.99, p for interaction between sex and treatment strategy=0.03). Overall, significant complications such as death, MI, stent thrombosis, bypass operation and perforations were rare and did not differ significantly by gender or treatment strategy. Plaque rupture and disrupted calcified nodules were more common in women. Conclusion: In a well-defined patient population with severely calcified coronary arteries, lesion preparation with an RA-strategy was superior to an MB-strategy in men. For women, both RA and MB strategies appear to have a similar success rate, although definitive conclusions are limited due to the small number of women in the trial.

Rationale and design of the TACTICS registry: Optical coherence tomography guided primary percutaneous coronary intervention for patients with acute coronary syndrome

BACKGROUND

Recent retrospective investigations have suggested that optical coherence tomography (OCT) enables the diagnosis of underlying acute coronary syndrome (ACS) causes such as plaque rupture, plaque erosion, and calcified nodule. The relationships of these etiologies with clinical outcomes, and the clinical utility of OCT-guided primary percutaneous coronary intervention (PCI) are not systematically studied in real-world ACS treatment settings.

METHODS

The TACTICS registry is an investigator-initiated, prospective, multicenter, observational study to be conducted at 21 hospitals in Japan. A total of 700 patients with ACS (symptom onset within 24 h) undergoing OCT-guided primary PCI will be enrolled. The primary endpoint of the study is to identify the underlying causes of ACS using OCT-defined morphological assessment of the culprit lesion. The key secondary clinical endpoints are hazard ratios of the composite of cardiovascular death, non-fatal myocardial infarction, heart failure, or ischemia-driven revascularization in patients with underlying etiologies at the 12- and 24-month follow-ups. The feasibility of OCT-guided primary PCI for ACS will be assessed by the achievement rates of optimal post-procedural results and safety endpoints.

CONCLUSION

The TACTICS registry will provide an overview of the underlying causes of ACS using OCT, and will reveal any difference in clinical outcomes depending on the underlying causes. The registry will also inform on the feasibility of OCT-guided primary PCI for patients with ACS.

Combined Use of Multiple Intravascular Imaging Techniques in Acute Coronary Syndrome

Recent advances in intravascular imaging techniques have made it possible to assess the culprit lesions of acute coronary syndrome (ACS) in the clinical setting. Intravascular ultrasound (IVUS) is the most commonly used intravascular imaging technique that provides cross-sectional images of coronary arteries. IVUS can assess plaque burden and vessel remodeling. Optical coherence tomography (OCT) is a high-resolution (10 μm) intravascular imaging technique that uses near-infrared light. OCT can identify key features of atheroma, such as lipid core and thin fibrous cap. Near-infrared spectroscopy (NIRS) can detect lipid composition by analyzing the near-infrared absorption properties of coronary plaques. NIRS provides a chemogram of the coronary artery wall, which allows for specific quantification of lipid accumulation. These intravascular imaging techniques can depict histological features of plaque rupture, plaque erosion, and calcified nodule in ACS culprit lesions. However, no single imaging technique is perfect and each has its respective strengths and limitations. In this review, we summarize the implications of combined use of multiple intravascular imaging techniques to assess the pathology of ACS and guide lesion-specific treatment.

Double Culprit Lesions in a Patient With ST-Segment Elevation Myocardial Infarction

We describe the case of simultaneous acute thrombotic occlusions in 2 major coronary arteries in a young patient admitted for extensive myocardial infarction. We highlight the importance of intravascular imaging to determine the underlying putative mechanism and to optimize treatment decisions. (Level of Difficulty: Intermediate.)

Prognostic implications of Neutrophil Extracellular Traps in coronary thrombi of patients with ST-elevation myocardial infarction

AIMS

The mechanisms of coronary thrombosis can influence prognosis after STEMI and allow for different treatment groups to be identified; an association between neutrophil extracellular traps (NETs) and unfavorable clinical outcomes has been suggested. Our aim was to determine the role played by NETs in coronary thrombosis and their influence on prognosis. The role of other histological features in prognosis and the association between NETs and bacteria in the coronary thrombi were also explored.

METHODS AND RESULTS

We studied 406 patients with STEMI in which coronary thrombi were consecutively obtained by aspiration during angioplasty between 2012 and 2018. Analysis of NETs in paraffin-embedded thrombi was based on the colocalization of specific NET components by means of confocal microscopy. Immunohistochemistry stains were used to identify plaque fragments. Fluorescence in situ hybridization was used to detect bacteria. NETs were detected in 51% of the thrombi [NET density, median (IQR): 25% (17-38%)]. The median follow-up was 47 months (95% CI 43-51); 105 (26%) patients experienced major adverse cardiac events (MACE). A significant association was found between the presence of NETs in coronary aspirates and the occurrence of MACE in the first 30 days after infarction (HR 2.82; 95% CI 1.26-6.35, p=.012), mainly due to cardiac deaths and stent thrombosis.

CONCLUSIONS

The presence of NETs in coronary thrombi was associated with a worse prognosis soon after STEMI. In some patients, NETs could be a treatment target and a feasible way to prevent reinfarction.

Plaque erosion and acute coronary syndromes: phenotype, molecular characteristics and future directions

Although acute coronary syndromes (ACS) remain one of the leading causes of death, the clinical presentation has changed over the past three decades with a decline in the incidence of ST-segment elevation myocardial infarction (STEMI) and an increase in non-STEMI. This epidemiological shift is at least partially explained by changes in plaque biology as a result of the widespread use of statins. Historically, atherosclerotic plaque rupture of the fibrous cap was thought to be the main culprit in ACS. However, plaque erosion with an intact fibrous cap is now responsible for about one third of ACS and up to two thirds of non-STEMI. Two major research approaches have enabled a better understanding of plaque erosion. First, advanced intravascular imaging has provided opportunities for an 'optical biopsy' and extensive phenotyping of coronary plaques in living patients. Second, basic science experiments have shed light on the unique molecular characteristics of plaque erosion. At present, patients with ACS are still uniformly treated with coronary stents irrespective of the underlying pathobiology. However, pilot studies indicate that patients with plaque erosion might be treated conservatively without coronary stenting. In this Review, we discuss the patient phenotype and the molecular characteristics in atherosclerotic plaque erosion and provide our vision for a potential major shift in the management of patients with plaque erosion.

Optical Coherence Tomography of Plaque Erosion: JACC Focus Seminar Part 2/3

Plaque erosion, a distinct histopathological and clinical entity, accounts for over 30% of acute coronary syndromes (ACS). Optical coherence tomography allows in vivo diagnosis of plaque erosion. Local flow perturbation with activation of Toll-like receptor 2 and CD8⁺ T cells and subsequent desquamation of endothelium and neutrophil extracellular trap formation contribute to mechanisms of plaque erosion. Compared with ACS patients with plaque rupture, those with plaque erosion are younger, have fewer traditional cardiovascular risk factors, have lower plaque burden, and are more likely to present with non-ST-segment elevation ACS. Early evidence suggests that in patients with ACS caused by plaque erosion, antithrombotic therapy without stenting may be a safe and effective option. Future randomized trials are needed to validate these findings. Clinical studies to develop noninvasive point-of-care biomarkers that distinguish plaque rupture from erosion, and to test novel therapies that target molecular pathways involved in plaque erosion are needed.

Optical Coherence Tomography of Plaque Vulnerability and Rupture: JACC Focus Seminar Part 1/3

Plaque rupture is the most common cause of acute coronary syndromes and sudden cardiac death. Characteristics and pathobiology of vulnerable plaques prone to plaque rupture have been studied extensively over 2 decades in humans using optical coherence tomography (OCT), an intravascular imaging technique with micron scale resolution. OCT studies have identified key features of plaque vulnerability and described the in vivo characteristics and spatial distribution of thin cap fibroatheromas as major precursors to plaque rupture. In addition, OCT data supports the evolving understanding of coronary heart disease as a panvascular process associated with inflammation. In the setting of high atherosclerotic burden, plaque ruptures often occur at multiple sites in the coronary arteries, and plaque progression and healing are dynamic processes modulated by systemic risk factors. This review details major investigations with intravascular OCT into the biology and clinical implications of plaque vulnerability and plaque rupture.

Association between apolipoprotein B/A1 ratio and coronary plaque vulnerability in patients with atherosclerotic cardiovascular disease: an intravascular optical coherence tomography study

Background

Apolipoprotein (Apo) A1 and Apo B are strongly associated with the risk of atherosclerotic cardiovascular disease (ASCVD). However, the relationship between the Apo B/A1 ratio and the morphology of coronary vulnerable plaques has not been fully elucidated in patients with ASCVD.

Methods

A total of 320 patients with ASCVD undergoing percutaneous coronary intervention were enrolled and assigned into acute coronary syndrome (ACS) or chronic coronary syndrome (CCS) group. The morphology of culprit plaque was analyzed by intravascular optical coherence tomography. Association between the Apo B/A1 ratio and coronary vulnerable plaques were evaluated using logistic regression models and receiver operator characteristic (ROC) curve analyses.

Results

The Apo B/A1 ratio was higher in ACS patients than CCS patients (0.77 ± 0.28 vs. 0.64 ± 0.22, P < 0.001) and it was also higher in patients with plaque rupture, erosion or thrombus than those without culprit plaques. The high Apo B/A1 ratio was associated with high percent of vulnerable plaques compared with low ratio group. The Apo B/A1 ratio was negatively related to fibrous cap thickness in lipid-rich plaque (r = − 0.228, P = 0.043). Univariate and multivariate logistic regression analyses revealed that the Apo B/A1 ratio was an independent factor of plaque rupture, erosion, and thrombus. The area under the ROC curve of the Apo B/A1 ratio for plaque rupture, erosion, and thrombus were 0.632, 0.624, and 0.670 respectively (P < 0.001 for all), which were higher than that of low-density lipoprotein cholesterol.

Conclusions

The Apo B/A1 ratio is an independent predictor for plaque rupture, erosion, and thrombus in patients with ASCVD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01381-9.

Association Between Visit-to-Visit Variability in Low-Density Lipoprotein Cholesterol and Plaque Rupture That Leads to Acute Coronary Syndrome

Background: The effect of intraindividual variability in lipid levels on the onset of acute coronary syndrome (ACS) remains uncertain. We evaluated the relationship between intraindividual variability in lipid levels and culprit lesion morphologies by optical coherence tomography (OCT).

Methods and Results: Seventy-four consecutive patients with ACS whose cholesterol levels were assessed ≥3 times during outpatient visits before the onset of ACS were enrolled in the study; 222 patients without significant stenotic lesions were used as a control group. Based on OCT findings of culprit lesions, ACS patients were categorized into a plaque rupture ACS (PR-ACS) group (n=44) or a non-plaque rupture ACS (NPR-ACS) group (erosion or calcified nodule; n=30). Visit-to-visit variability in lipid levels was evaluated using the corrected variability independent of the mean (cVIM). Patients with ACS had significantly higher low-density lipoprotein cholesterol (LDL-C) levels and cVIM in LDL-C than the control group. The PR-ACS group had significantly higher mean LDL-C levels and greater cVIM in LDL-C than the control group. The PR-ACS group had a significantly higher cVIM than the NPR-ACS group, despite similar mean LDL-C levels. Multivariate analysis revealed that higher cVIM of LDL-C was an independent predictor of PR-ACS (odds ratio 1.06; P=0.018).

Conclusions: In addition to the LDL-C level, greater visit-to-visit variability in LDL-C levels may be associated with the onset of ACS induced by plaque rupture.

Predictors of non-stenting strategy for acute coronary syndrome caused by plaque erosion: four-year outcomes of the EROSION study

BACKGROUND

The EROSION study demonstrated that patients with an acute coronary syndrome (ACS) caused by plaque erosion could be treated with antithrombotic therapy without stenting. However, the long-term prognosis of this strategy is still unclear.

AIMS

The aim of this study was to test whether a non-stenting antithrombotic strategy was still effective at four-year follow-up and to explore potential predictors of long-term prognosis.

METHODS

This study was a long-term follow-up of the EROSION study. Follow-up was conducted by phone call or clinical visit. Patients were divided into two groups - those with target lesion revascularisation (the TLR group), and the non-TLR group.

RESULTS

Out of 55 patients who completed one-month follow-up, 52 patients finished four-year follow-up. The median duration was 4.8 years (range, 4.2-5.8 years). The majority of patients remained free from events, and all patients were free from hard endpoints (death, myocardial infarction, stroke, bypass surgery, or heart failure). Only one patient had gastrointestinal bleeding, and 11 patients underwent TLR. Patients in the non-TLR group had more optical coherence tomography (OCT) thrombus reduction from baseline to one month; 95% of patients in the non-TLR group versus 45% in the TLR group (p=0.001) met the primary endpoint (thrombus volume reduction >50%). Angiographic results showed that the TLR group had less improvement in diameter stenosis (p=0.014) at one month compared with the non-TLR group.

CONCLUSIONS

Four-year follow-up findings reconfirmed the safety of an antithrombotic therapy without stenting for ACS caused by erosion. Patients with better response to antithrombotic therapy in the first month were less likely to require stent implantation during the next four years.

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

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

Morphological Plaque Characteristics and Clinical Outcomes in Patients With Acute Coronary Syndrome and a Cancer History

Background

Although patients with a cancer history have a 2 to 3 times higher risk for acute coronary syndrome (ACS), the morphological characteristics of ACS culprit plaque in those patients and their relations with clinical outcomes remain unknown.

Methods and Results

This retrospective, multicenter, observational cohort study included consecutive patients with ACS who underwent optical coherence tomography‐guided emergent percutaneous coronary intervention. Patients were categorized into those without a cancer history, those with a cancer history, and those currently receiving cancer treatment. ACS culprit lesions were classified as plaque rupture, plaque erosion, or calcified nodule using optical coherence tomography. Plaque erosion frequency was significantly higher in culprit lesions of patients with current cancer and patients with cancer history than in those of patients without cancer history (56.3% versus 61.7% versus 36.5%). Calcified nodule incidence was significantly higher in patients without cancer history than in patients with current cancer and patients without cancer history (patients with current cancer: 12.4% versus patients without cancer history: 25.5% versus patients without cancer history: 12.6%, P<0.001). Cancer history was independently associated with nonplaque rupture (plaque erosion or calcified nodule) in ACS culprit lesions (odds ratio, 4.00; P<0.001). Cancer history was independently associated with major adverse cardiovascular events (hazard ratio [HR], 1.98; P=0.002). Nonplaque rupture in ACS culprit lesions was independently associated with major adverse cardiovascular events (HR, 1.60; P=0.011).

Conclusions

Patients with a cancer history had significantly worse clinical outcomes after ACS than those without a cancer history. Those with a cancer history had significantly higher plaque erosion and calcified nodule incidences in the ACS culprit lesions, which might partly explain their worse clinical outcomes.

Registration

URL: www.umin.ac.jp/ctr/index.htm. Unique Identifier: UMIN000038442.

Relationship among clinical characteristics, morphological culprit plaque features, and long-term prognosis in patients with acute coronary syndrome

Culprit lesions of acute coronary syndrome (ACS) could be classified as plaque rupture (PR), erosion, or calcified nodule (CN). We aimed to determine the relationship among clinical characteristics, morphological plaque features, and long-term prognosis in ACS. Patients with ACS, who underwent pre-intervention optical coherence tomography between April 2013 and July 2018 were retrospectively enrolled, and classified into the three groups based on the culprit lesion morphology. In the 436 patients enrolled, incidences of PR, erosion, and CN in ACS culprit lesions were 46.1, 39.9, and 14.0%, respectively. Plaque erosion was more frequent in men aged < 60 years and CN was more frequent in older adults in both sexes (≥ 80 years) (P < 0.001). Patients with CN had a higher incidence of hemodialysis treatment (P < 0.001) and diabetes (P = 0.003). Multivariate analysis revealed that ST elevation myocardial infarction (STEMI) (P = 0.049) and presence of thin-cap fibroatheroma (TCFA) at the culprit lesion were independently associated with PR; in younger patients (< 60 year), preserved left ventricular ejection fraction and lower incidence of TCFA were correlated with plaque erosion; and older age, non-STEMI, or unstable angina pectoris, higher serum brain natriuretic peptide levels, and lower incidence of TCFA were independently associated with CN. Multivariable analysis revealed that CN (odds ratio [OR] 1.990, P = 0.005), male sex (OR 2.012, P = 0.004), and older age (OR 1.036, P < 0.001) were independently associated with future adverse events during a median follow-up of 757 days. Different patient characteristics and morphological features were associated with the type of culprit lesion in patients with ACS.

Association of the age shock index with coronary plaque characteristics in ST-segment elevation myocardial infarction: A 3-vessel optical coherence tomography study

OBJECTIVES

We investigated whether the age shock index (SI) was associated with coronary plaque characteristics in patients with ST-segment elevation myocardial infarction (STEMI) using optical coherence tomography (OCT).

BACKGROUND

The age SI is a simple clinical parameter that effectively predicts poor clinical outcomes among patients with STEMI.

METHODS

This retrospective study evaluated 408 STEMI patients who underwent 3-vessel OCT during emergency percutaneous coronary interventions at a single center between January 2017 and October 2018. Patients were divided into groups with low or high age SI values (<41 vs. ≥41). Plaque characteristics were compared between the two groups for both culprit lesions (n = 408) and non-culprit lesions (n = 1,077).

RESULTS

In culprit lesions, patients with a high age SI (≥41) were more likely to have plaque rupture (61.0% vs. 56.8%, p = .002) and thinner fibrous caps (fibrous cap thickness [FCT]: 40.0 [33.0-53.0] μm vs. 46.0 [36.0-63.8] μm, p = .021). In non-culprit lesions, patients with a high age SI were more likely to have high-risk plaques (29.9% vs. 17.8%, p = .018; simultaneous presence of a minimal lumen area of <3.5 mm² , maximum lipid arc of >180°, FCT of <75 μm, and macrophage accumulation). Plaque-based analyses revealed that patients with a high age SI had larger lipid cores and lesser FCT.

CONCLUSIONS

Patients with STEMI and a high age SI had increased risks of culprit plaque rupture and high-risk non-culprit plaques, and vulnerable plaque features at the culprit and non-culprit lesions. Therefore, a high age SI in patients with STEMI may indicate greater pancoronary vulnerability.

Evaluation of coronary plaques and atherosclerosis using optical coherence tomography

Introduction: Coronary angiography (CAG) is the standard modality for assessing coronary stenosis; however, it has limitations in assessing coronary plaque morphology. Optical coherence tomography (OCT) is a high-resolution (10-20 μm) light-based intravascular imaging technique that can identify more detailed coronary plaque morphology compared to other intravascular imaging modalities. OCT is remarkable for characterizing fibrous, fibrocalcific, and lipid-rich plaques. The capabilities of OCT are well suited for discriminating three types of unstable plaque morphologies underlying coronary thrombosis, such as plaque rupture, erosion, and calcified nodules. The high resolution of OCT makes it possible to identify important features of vulnerable plaques, such as thin-cap (<65 μm thick) fibroatheroma, macrophages, vasa vasorum, and cholesterol crystals.Areas covered: This review summarizes the clinical impact of OCT and its efficacy in identifying plaque components and morphological features associated with plaque vulnerability.Expertopinion: The unique properties of OCT as a tool for investigating high-risk lesions have greatly contributed to a better understanding of plaque vulnerability. Consequently, OCT has led to significant changes in medical treatment and percutaneous coronary intervention strategies for acute coronary syndrome. Further development and investigation of OCT are necessary to better predict and manage acute coronary events in the future.

Can OCT change the therapeutic strategy in ACS due to plaque erosion?

The pathophysiology of acute coronary syndromes was thought to be coronary thrombosis over a plaque rupture. Autopsy studies revealed that not all cases were due to plaque rupture, even denuded endothelium or calcific nodule can beget a thrombus. Introduction of OCT made, in vivo recognition of lesion morphology clear. Plaque ruptures are most common and need primary angioplasty. Recent studies established plaque erosion is responsible for ACS in one third of the cases and majority of them present as Non ST elevation myocardial infarction and commonly found in young patients without major risk factors. Evidence from recent studies suggested that stenting can be deferred and they can be managed conservatively with good long term outcomes. More randomized trials are needed comparing plaque rupture and plaque erosion as regards conservative versus invasive management. If these studies substantiate the concept of conservative management, it will lead to a paradigm shift in their management.

Early Vascular Response to Ultrathin Biodegradable Polymer Sirolimus-Eluting Stents for the Treatment of ST-Elevation Myocardial Infarction After Plaque Rupture

Recent clinical studies suggest that newer-generation drug-eluting stents that combine ultrathin struts and nanocoating (biodegradable polymer sirolimus-eluting stents, BP-SES) could improve long-term clinical outcomes in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). However, the early vascular response to BP-SES in these patients has not been investigated so far.We examined this response in 20 patients with STEMI caused by plaque rupture using frequency-domain optical coherence tomography (OCT) to understand the underlying mechanisms. Plaque rupture was diagnosed by OCT before PCI with BP-SES implantation was performed. OCT was again performed before the final angiography (post-PCI) and after 2 weeks (2W-OCT).BP-SES placement caused protrusion of atherothrombotic material into the stent lumen and incomplete stent apposition in all patients. After 2 weeks, incomplete stent apposition was significantly reduced (% malapposed struts: post-PCI 4.7 ± 3.3%; 2W-OCT 0.9 ± 1.2%; P < 0.0001), and the percentage of uncovered struts also significantly decreased (% uncovered struts: post-PCI; 69.8 ± 18.3%: 2W-OCT; 29.6 ± 11.0%, P < 0.0001). The maximum protrusion area of the atherothrombotic burden was significantly reduced (post-PCI 1.36 ± 0.70 mm²; 2W-OCT 0.98 ± 0.55 mm²; P = 0.004).This study on the early vascular responses following BP-SES implantation showed rapid resolution of atherothrombotic material and progression of strut apposition and coverage. (UMIN000041324).

Prevalence, Features, and Prognosis of Artery-to-Artery Embolic ST-Segment-Elevation Myocardial Infarction: An Optical Coherence Tomography Study

Background The major underlying mechanisms contributing to acute coronary syndrome are plaque rupture, plaque erosion, and calcified nodule. Artery-to-artery embolic myocardial infarction (AAEMI) was defined as ST-segment-elevation myocardial infarction caused by migrating thrombus formed at the proximal ruptured plaque. The aim of this study was to investigate the prevalence and clinical features of AAEMI by using optical coherence tomography. Methods and Results This study retrospectively enrolled 297 patients with ST-segment-elevation myocardial infarction who underwent optical coherence tomography before percutaneous coronary intervention. Patients were divided into 4 groups consisting of plaque rupture, plaque erosion, calcified nodule, and AAEMI according to optical coherence tomography findings. The prevalence of AAEMI was 3.4%. The culprit vessel in 60% of patients with AAEMI was right coronary artery. Minimum lumen area at the culprit site was larger in AAEMI compared with plaque rupture, plaque erosion, and calcified nodule (4.0 mm² [interquartile range (IQR), 2.2-4.9] versus 1.0 mm² [IQR, 0.8-1.3] versus 1.0 mm² [IQR, 0.8-1.2] versus 1.1 mm² [IQR, 0.7-1.6], P<0.001). Lumen area at the rupture site was larger in patients with AAEMI compared with patients with plaque rupture (4.4 mm² [IQR, 2.5-6.7] versus 1.5 mm² [IQR, 1.0-2.4], P<0.001). In patients with AAEMI, the median minimum lumen area at the occlusion site was 1.2 mm² (IQR, 1.0-2.1), 40% of them had nonstent strategy, and the 3-year major adverse cardiac event rate was 0%. Conclusions AAEMI is a rare cause for ST-segment-elevation myocardial infarction and has unique morphological features of plaque including larger lumen area at rupture site and smaller lumen area at the occlusion site.

High Plasma Myeloperoxidase Is Associated with Plaque Erosion in Patients with ST-Segment Elevation Myocardial Infarction

We aimed to investigate the association between plasma myeloperoxidase (MPO) and plaque erosion in patients presenting with ST-segment elevation myocardial infarction (STEMI). Two hundred and fifty-two patients with STEMI who underwent optical coherence tomography (OCT) evaluation of culprit lesion were prospectively enrolled. Of them, 92 and 80 patients were identified with plaque rupture and plaque erosion, respectively. Plasma MPO levels, measured using enzyme-linked immunoassay, were significantly higher in patients with plaque erosion versus plaque rupture (median (interquartile range), 96.3 ng/mL [44.2-173.3] vs. 41.7 ng/mL (29.2-66.3); p < 0.001). Multivariable logistic regression analysis indicated that plasma MPO was independently associated with plaque erosion (odds ratio, 3.25; 95% confidence interval, 1.37-7.76; p = 0.008). The area under the receiver-operating characteristic curve was 0.75 for MPO to discriminate between plaque erosion and plaque rupture. Plasma MPO level significantly correlated with plaque erosion in patients with STEMI.

The relationship between residual cholesterol risk and plaque characteristics in patients with acute coronary syndrome: Insights from an optical coherence tomography study

BACKGROUND AND AIMS

The impact of residual cholesterol risk (RCR) on plaque characteristics is not fully understood. The study aims to explore the relationship between RCR and plaque features in patients presenting with acute coronary syndrome (ACS).

METHODS

All ACS patients undergoing pre-intervention optical coherence tomography (OCT) with high-sensitivity C-reactive protein (hs-CRP) <2 mg/L on admission were retrospectively enrolled from January to December 2017, at Beijing Anzhen Hospital, Capital Medical University. RCR was defined as low density lipoprotein cholesterol (LDL-C) ≥1.8 mmol/L. Patients were divided into the RCR and non-RCR groups according to baseline LDL-C.

RESULTS

A total of 90 patients (94 vessels) were included, with 50 in the RCR group and 40 in the non-RCR group, respectively. Compared with the non-RCR group, patients in the RCR group were younger (54.0 ± 11.04 vs. 58.4 ± 9.59, p = 0.049) and had a higher incidence of multivessel disease (6.0% vs. 2.5%, p = 0.028). With regard to plaque characteristics, fibrous plaque (0.0% vs 12.5%, p = 0.003) was less and fibroatheroma (79.6% vs. 50.0%, p = 0.028) was more frequently seen in the RCR group. Patients in the RCR group were more prone to present with plaque rupture (24.1% vs 5.0%, p = 0.008). Cholesterol crystal (22.2% vs 12.5%, p = 0.226) and thin-cap fibroatheroma (25.9% vs. 12.5%, p = 0.109) were more common in the RCR group, though without statistical difference. Multivariate logistic regression showed that RCR (odds ratio [OR]: 7.95, p = 0.011) and smoking (OR: 4.08, p = 0.026) were independent risk factors of plaque rupture in our patients.

CONCLUSIONS

ACS patients with RCR are more likely to have atherosclerotic plaque and plaque rupture, indicating a more vulnerable plaque phenotype.

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.

Clinical use of intracoronary imaging. Part 2: acute coronary syndromes, ambiguous coronary angiography findings, and guiding interventional decision-making: an expert consensus document of the European Association of Percutaneous Cardiovascular Interventions

This consensus document is the second of two reports summarizing the views of an expert panel organized by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) on the clinical use of intracoronary imaging including intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near infrared spectroscopy (NIRS)-IVUS. Beyond guidance of stent selection and optimization of deployment, invasive imaging facilitates angiographic interpretation and may guide treatment in acute coronary syndrome. Intravascular imaging can provide additional important diagnostic information when confronted with angiographically ambiguous lesions and allows assessment of plaque morphology enabling identification of vulnerability characteristics. This second document focuses on useful imaging features to identify culprit and vulnerable coronary plaque, which offers the interventional cardiologist guidance on when to adopt an intracoronary imaging-guided approach to the treatment of coronary artery disease and provides an appraisal of intravascular imaging-derived metrics to define the haemodynamic significance of coronary lesions.

Clinical Significance of the Presence or Absence of Lipid-Rich Plaque Underneath Intact Fibrous Cap Plaque in Acute Coronary Syndrome

Background Although most coronary thromboses occur on the surface of lipid-rich plaque ( LRP ) with plaque rupture ( PR ), previous pathological and optical coherence tomography studies demonstrated diversity in the morphological characteristics of culprit plaque underlying the thrombus, including lesions with intact fibrous cap ( IFC ). We investigated the clinical significance of IFC in relation to the presence or absence of LRP observed via optical coherence tomography in culprit lesions of acute coronary syndrome. Methods and Results We investigated 510 patients with acute coronary syndrome who underwent optical coherence tomography for the culprit lesion. Optical coherence tomography analysis included the presence or absence of PR , which were categorized into the PR group and the IFC group, respectively. The IFC group was further categorized on the basis of the presence of LRP . Incidence of major adverse cardiac events ( MACEs ), including cardiac death, myocardial infarction, and clinically driven remote revascularizations, was compared. Culprit lesions were categorized into 328 PR s and 182 IFC s. MACEs occurred in 85 patients (16.7%) during the median follow-up duration of 621 days. LRP was detected in 325 lesions (99%) with PR , whereas 60 (33.0%) of the lesions with IFC did not show LRP . Kaplan-Meier analysis revealed significantly lower MACEs in the IFC group compared with the PR group. Furthermore, the IFC group without LRP showed significantly lower MACEs compared with the IFC group with LRP . Multivariate Cox proportional hazards analysis demonstrated that IFC without LRP was an independent predictor of better prognosis. Conclusions Exclusion of LRP underneath IFC culprit lesions in acute coronary syndrome may predict a lower risk of future MACEs .

Ethnic Differences in the Pathobiology of Acute Coronary Syndromes Between Asians and Whites

Ethnic differences in the pathobiology of acute coronary syndromes (ACS) have not been systematically studied. We compared the underlying mechanisms of ACS between Asians and Whites. ACS patients with the culprit lesion imaged by optical coherence tomography were included. Patients were stratified into ST-elevation myocardial infarction (STEMI) and non-ST-elevation-ACS (NSTE-ACS), and baseline characteristics, underlying mechanisms of ACS, and culprit plaque characteristics were compared between Asians and Whites. Of 1,225 patients, 1,019 were Asian (567 STEMI and 452 NSTE-ACS) and 206 were White (71 STEMI and 135 NSTE-ACS). Asians had more diabetes and hypertension among STEMI patients; among NSTE-ACS patients, Asians had higher prevalence of diabetes and renal insufficiency, and lower prevalence of hyperlipidemia. There were no differences in the incidence of plaque rupture, plaque erosion and calcified plaque between Asians and Whites with STEMI (61.2%, 28.6%, 10.2% vs 46.5%, 38.0%, 15.5%, respectively, p = 0.055). Among NSTE-ACS patients, there was a significant difference between Asians and Whites (40.5%, 47.6%, 11.9% vs 27.4%, 48.9%, 23.7%, respectively, p = 0.001). After adjustment for clinical confounders, the risk of plaque rupture (p = 0.713), plaque erosion (p = 0.636), and calcified plaque (p = 0.986) was similar between the groups with STEMI. In NSTE-ACS patients, the only difference was an increased risk of calcified plaque in Whites (odds ratio: 2.125, 95% confidence interval: 1.213 to 3.723, p = 0.008). In conclusion, after adjustment for clinical confounders, Asian and White patients presenting with STEMI and NSTE-ACS showed similar underlying mechanisms of ACS, except for a higher risk of calcified plaque in Whites with NSTE-ACS.

Plaque morphology assessed by optical coherence tomography in the culprit lesions of the first episode of acute myocardial infarction in patients with low low-density lipoprotein cholesterol level

BACKGROUND

There remains a residual risk for acute myocardial infarction (AMI) even with low low-density lipoprotein cholesterol (LDL-C) levels. This study aimed to characterize the culprit lesion morphology of AMI by optical coherence tomography (OCT) in patients with low LDL-C.

METHODS

Four-hundred and nine culprit lesions of 409 patients with their first presentation of AMI imaged by OCT were investigated. OCT analysis included the presence of plaque rupture and thin-capped fibroatheroma (TCFA). Fibrous cap thickness and lipid length were also measured. Intravascular ultrasound (IVUS) was performed in 368 (90.0%) patients. OCT and IVUS findings were compared between patients with LDL-C < 100 mg/dl (lower-LDL group) and those with LDL ≥ 100 mg/dl (higher-LDL group).

RESULTS

Lower-LDL group included 93 (22.7%) patients. Plaque rupture (54.8% vs. 68.7%, p = 0.018) and TCFA (39.8% vs. 54.6%, p = 0.013) were less frequently observed in lower-LDL than in higher-LDL. Fibrous cap was thicker [73 (59-109) µm vs. 63 (57-83) µm, p = 0.028] and lipid length was smaller [5.4 (2.3-9.9) mm vs. 7.1 (4.1-10.5) mm, p = 0.012] in lower-LDL than in higher-LDL. There were no significant differences in IVUS parameters including plaque burden or remodeling index between the two groups.

CONCLUSIONS

Patients with lower LDL-C showed more prevalent intact fibrous cap and less vulnerable features in the culprit lesions, which may suggest the need for exploring a specific strategy for the prevention of plaque erosion in low LDL-C subjects.

Calcification in Atherosclerotic Plaque Vulnerability: Friend or Foe?

Calcification is a clinical marker of atherosclerosis. This review focuses on recent findings on the association between calcification and plaque vulnerability. Calcified plaques have traditionally been regarded as stable atheromas, those causing stenosis may be more stable than non-calcified plaques. With the advances in intravascular imaging technology, the detection of the calcification and its surrounding plaque components have evolved. Microcalcifications and spotty calcifications represent an active stage of vascular calcification correlated with inflammation, whereas the degree of plaque calcification is strongly inversely related to macrophage infiltration. Asymptomatic patients have a higher content of plaque calcification than that in symptomatic patients. The effect of calcification might be biphasic. Plaque rupture has been shown to correlate positively with the number of spotty calcifications, and inversely with the number of large calcifications. There may be certain stages of calcium deposition that may be more atherogenic. Moreover, superficial calcifications are independently associated with plaque rupture and intraplaque hemorrhage, which may be due to the concentrated and asymmetrical distribution of biological stress in plaques. Conclusively, calcification of differential amounts, sizes, shapes, and positions may play differential roles in plaque homeostasis. The surrounding environments around the calcification within plaques also have impacts on plaque homeostasis. The interactive effects of these important factors of calcifications and plaques still await further study.

Plaque erosion: a new in vivo diagnosis and a potential major shift in the management of patients with acute coronary syndromes

Pathology and in vivo imaging studies have identified superficial plaque erosion as a frequent and important mechanism underlying acute coronary syndromes (ACS). In contrast with plaque rupture, the pathophysiological mechanisms leading to plaque erosion remain poorly understood. The advent of intravascular imaging techniques, particularly optical coherence tomography, has aided understanding of this mode of ACS in vivo by complementing previous insights from pathology studies. Appreciation of the distinct biological and clinical mechanisms of plaque erosion points to the possibility of tailored management strategies for patients presenting with ACS.

Clinical and Laboratory Predictors for Plaque Erosion in Patients With Acute Coronary Syndromes

Background Plaque erosion is responsible for 25% to 40% of patients with acute coronary syndromes (ACS). Recent studies suggest that anti-thrombotic therapy without stenting may be an option for this subset of patients. Currently, however, an invasive procedure is required to make a diagnosis of plaque erosion. The aim of this study was to identify clinical or laboratory predictors of plaque erosion in patients with ACS to enable a diagnosis of erosion without additional invasive procedures. Methods and Results Patients with ACS who underwent optical coherence tomography imaging were selected from 11 institutions in 6 countries. The patients were classified into plaque rupture, plaque erosion, or calcified plaque, and predictors were identified using multivariable logistic modeling. Among 1241 patients with ACS, 477 (38.4%) patients were found to have plaque erosion. Plaque erosion was more frequent in non-ST-segment elevation-ACS than in ST-segment-elevation myocardial infarction (47.9% versus 29.8%, P=0.0002). Multivariable logistic regression models showed 5 independent parameters associated with plaque erosion: age <68 years, anterior ischemia, no diabetes mellitus, hemoglobin >15.0 g/dL, and normal renal function. When all 5 parameters are present in a patient with non-ST-segment elevation-ACS, the probability of plaque erosion increased to 73.1%. Conclusions Clinical and laboratory parameters associated with plaque erosion are explored in this retrospective registry study. These parameters may be useful to identify the subset of ACS patients with plaque erosion and guide them to conservative management without invasive procedures. The results of this exploratory analysis need to be confirmed in large scale prospective clinical studies. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT03479723.

Clinical use of intracoronary imaging. Part 2: acute coronary syndromes, ambiguous coronary angiography findings, and guiding interventional decision-making: an expert consensus document of the European Association of Percutaneous Cardiovascular Interventions

This consensus document is the second of two reports summarizing the views of an expert panel organized by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) on the clinical use of intracoronary imaging including intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near infrared spectroscopy (NIRS)-IVUS. Beyond guidance of stent selection and optimization of deployment, invasive imaging facilitates angiographic interpretation and may guide treatment in acute coronary syndrome. Intravascular imaging can provide additional important diagnostic information when confronted with angiographically ambiguous lesions and allows assessment of plaque morphology enabling identification of vulnerability characteristics. This second document focuses on useful imaging features to identify culprit and vulnerable coronary plaque, which offers the interventional cardiologist guidance on when to adopt an intracoronary imaging-guided approach to the treatment of coronary artery disease and provides an appraisal of intravascular imaging-derived metrics to define the haemodynamic significance of coronary lesions.

Thrombus resolution with tirofiban in the conservative management of patients presenting with plaque erosion

OBJECTIVE

Recent studies suggest that conservative management with antithrombotic therapy without stenting may be an option in selected patients with acute coronary syndrome (ACS). We evaluated whether a glycoprotein IIb/IIIa inhibitor, tirofiban, would offer additional benefit in patients with plaque erosion presenting with ACS who were treated with antiplatelet therapy without stenting.

PATIENTS AND METHODS

Forty-nine patients who completed 1-year follow-up optical coherence tomography imaging in the EROSION study were divided into two groups: tirofiban (n=32) versus no tirofiban (n=17). Thrombus volume, thrombus burden, and the incidence of major adverse cardiovascular events were evaluated.

RESULTS

At baseline, the tirofiban group had similar thrombus volume [3.73 (1.27-12.49) vs. 3.51 (1.70-8.65) mm, P=0.983] and marginally greater thrombus burden [17.9 (10.1-26.1) vs. 10.6 (6.8-19.0)%, P=0.097]. At 1 month, the tirofiban group had smaller residual thrombus volume [0.00 (0.00-1.78) vs. 0.94 (0.07-4.20) mm, P=0.054], thrombus burden [0.0 (0.0-6.4) vs. 7.0 (1.8-14.8)%, P=0.024], and greater reduction of thrombus volume (85.4±24.6 vs. 67.1±27.1%, P=0.021). These differences were maintained up to 1 year. Complete resolution of thrombus at 1 month was more frequent in the tirofiban group (53.1 vs. 17.6%, P=0.031). None of the patients experienced major bleeding during the initial hospitalization. The 1-year major adverse cardiovascular events rate was not different (5.6 vs. 15.0%, P=0.336).

CONCLUSION

In patients with ACS caused by plaque erosion who were managed conservatively without stenting, tirofiban provided additional benefit in reducing residual thrombus without an increased risk for bleeding.

Angiographic features of patients with coronary plaque erosion

BACKGROUND

Although an in vivo diagnosis of coronary plaque erosion has become possible by optical coherence tomography (OCT), angiographic characteristics of erosion have not been studied. The aim of this study was to investigate the angiographic features of plaque erosion in patients with non-ST elevation acute coronary syndromes (NSTE-ACS).

METHODS

Patients with NSTE-ACS who underwent OCT of the culprit lesion were collected at 11 institutions from 6 countries. Patients were classified as erosion or non-erosion based on OCT images. Angiographic features of both groups were compared.

RESULTS

Among 494 cases with NSTE-ACS, 242 had plaque erosion and 252 had non-erosion. Compared to non-erosion group, erosion patients had less multivessel disease (28.5% vs. 49.6%, p < 0.001), lower Jeopardy score (4.2 vs. 5.0, p < 0.001), lower Gensini score (21.3 vs. 25.6, p = 0.014), and lower Syntax score (8.9 vs. 11.5, p < 0.001). With regard to the culprit lesion morphology, plaque erosion group had smaller reference diameter (2.8 mm vs. 3.0 mm, p = 0.032), less frequent type B2/C lesions (51.2% vs. 71.8%, p < 0.001), and lower prevalence of calcification (4.1% vs. 13.9%, p < 0.001) and thrombus (16.5% vs. 28.2%, p = 0.002). In the mid left anterior descending artery (LAD), erosion was significantly more frequent than non-erosion (30.2% vs. 21.8%, p = 0.034).

CONCLUSIONS

Patients with NSTE-ACS caused by plaque erosion have less complex angiographic features both at the 3-vessel level and at the culprit lesion level. Plaque erosion was frequently found in the mid LAD.

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

Aims

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

Methods and results

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

Conclusions

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

EROSION Study (Effective Anti-Thrombotic Therapy Without Stenting: Intravascular Optical Coherence Tomography-Based Management in Plaque Erosion): A 1-Year Follow-Up Report

BACKGROUND

The initial EROSION study (Effective Anti-Thrombotic Therapy Without Stenting: Intravascular Optical Coherence Tomography-Based Management in Plaque Erosion) demonstrated that patients with acute coronary syndrome caused by plaque erosion might be stabilized with aspirin and ticagrelor without stenting for ≤1 month. However, a long-term evaluation of outcomes is lacking. The aim of this study was to assess whether the initial benefit of noninterventional therapy for patients with acute coronary syndrome caused by plaque erosion is maintained for ≤1 year.

METHODS AND RESULTS

Among 53 patients who completed clinical follow-up, 49 underwent repeat optical coherence tomography imaging at 1 year. Median residual thrombus volume decreased significantly from 1 month to 1 year (0.3 mm³ (0.0-2.0 mm³] versus 0.1 mm³ [0.0-2.0 mm³]; P=0.001). Almost half of the patients (46.9%) had no residual thrombus at 1 year. Minimal effective flow area remained unchanged (2.1 mm² [1.5-3.8 mm²] versus 2.1 mm² [1.6-4.0 mm²]; P=0.152). Among 53 patients, 49 (92.5%) remained free from major adverse cardiovascular event for ≤1 year: 3 (5.7%) patients required revascularization because of exertional angina and 1 (1.9%) patient had gastrointestinal bleeding.

CONCLUSIONS

One-year follow-up optical coherence tomography demonstrated a further decrease in thrombus volume between 1-month and 1-year follow-up. A majority (92.5%) of patients with acute coronary syndrome caused by plaque erosion managed with aspirin and ticagrelor without stenting remained free of major adverse cardiovascular event for ≤1 year.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02041650.