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

Precision Medicine in Acute Coronary Syndromes

Nowadays, current guidelines on acute coronary syndrome (ACS) provide recommendations mainly based on the clinical presentation. However, greater attention is being directed to the specific pathophysiology underlying ACS, considering that plaque destabilization and rupture leading to luminal thrombotic obstruction is not the only pathway involved, albeit the most recognized. In this review, we discuss how intracoronary imaging and biomarkers allow the identification of specific ACS endotypes, leading to the recognition of different prognostic implications, tailored management strategies, and new potential therapeutic targets. Furthermore, different strategies can be applied on a personalized basis regarding antithrombotic therapy, non-culprit lesion revascularization, and microvascular obstruction (MVO). With respect to myocardial infarction with non-obstructive coronary arteries (MINOCA), we will present a precision medicine approach, suggested by current guidelines as the mainstay of the diagnostic process and with relevant therapeutic implications. Moreover, we aim at illustrating the clinical implications of targeted strategies for ACS secondary prevention, which may lower residual risk in selected patients.

Assessment of Residual Vasospasm in Patients with Plaque Rupture or Plaque Erosion using Optical Coherence Tomography

AIMS

Coronary vasospasm is associated with acute coronary syndrome (ACS) and may persist during primary percutaneous coronary intervention (PCI). We aimed to elucidate the incidence, morphological characteristics, and prognostic impact of residual vasospasm in plaque rupture (PR) and plaque erosion (PE) lesions using optical coherence tomography (OCT).

METHODS

We enrolled 142 patients with ACS who underwent OCT-guided primary PCI. All patients received intracoronary vasodilators before OCT examination. Residual vasospasm was identified as intimal gathering and categorised as polygonal- or wavy- patterned depending on the luminal shape. A wavy pattern was defined as a curved intimal surface line. A polygonal pattern was defined as a lumen with multiple angles. The incidence of major cardiovascular events, defined as death, non-fatal myocardial infarction, stroke, and any revascularization, within 1-year of PCI was identified.

RESULTS

The prevalence of residual vasospasm in PR and PE was 15.1% (13 of 86) and 21.4% (12 of 56), respectively. Wavy pattern was the major shape of the residual vasospasm. Polygonal-patterned lumen was more frequently observed in PR than in PE (38.5 vs. 8.3 %). The polygonal-patterned lumens had significantly larger lipid arcs (257.9 vs. 78.0 °; P＜0.01), and significantly smaller areas (1.27 vs. 1.88 mm2; P=0.05) than wavy-patterned lumens. Residual vasospasm had a prognostic impact on PR but not PE at 1-year of successful primary PCI.

CONCLUSION

Considerable proportion of ACS including both PR and PE had residual vasospasm with variable morphological feature and different prognostic impact.

Intravascular Imaging Findings After PCI in Patients With Focal and Diffuse Coronary Artery Disease

BACKGROUND

Following percutaneous coronary intervention (PCI), optical coherence tomography provides prognosis information. The pullback pressure gradient is a novel index that discriminates focal from diffuse coronary artery disease based on fractional flow reserve pullbacks. We sought to investigate the association between coronary artery disease patterns, defined by coronary physiology, and optical coherence tomography after stent implantation in stable patients undergoing PCI.

METHODS AND RESULTS

This multicenter, prospective, single-arm study was conducted in 5 countries (NCT03782688). Subjects underwent motorized fractional flow reserve pullbacks evaluation followed by optical coherence tomography-guided PCI. Post-PCI optical coherence tomography minimum stent area, stent expansion, and the presence of suboptimal findings such as incomplete stent apposition, stent edge dissection, and irregular tissue protrusion were compared between patients with focal versus diffuse disease. Overall, 102 patients (105 vessels) were included. Fractional flow reserve before PCI was 0.65±0.14, pullback pressure gradient was 0.66±0.14, and post-PCI fractional flow reserve was 0.88±0.06. The mean minimum stent area was 5.69±1.99 mm2 and was significantly larger in vessels with focal disease (6.18±2.12 mm2 versus 5.19±1.72 mm2, P=0.01). After PCI, incomplete stent apposition, stent edge dissection, and irregular tissue protrusion were observed in 27.6%, 10.5%, and 51.4% of the cases, respectively. Vessels with focal disease at baseline had a lower prevalence of incomplete stent apposition (11.3% versus 44.2%, P=0.002) and more irregular tissue protrusion (69.8% versus 32.7%, P<0.001).

CONCLUSIONS

Baseline coronary pathophysiological patterns are associated with suboptimal imaging findings after PCI. Patients with focal disease had larger minimum stent area and a higher incidence of tissue protrusion, whereas stent malapposition was more frequent in patients with diffuse disease.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

MHR levels are an independent risk factor for ISNA.

Lipid Content Distribution and its Clinical Implication in Patients with Acute Myocardial Infarction-Plaque Erosion: Results from the Prospective OCTAMI Study

AIMS

Plaque erosion (PE) is one of the main plaque phenotypes of acute coronary syndrome (ACS). However, the underlying plaque component and distribution have not been systematically analysed. This study aims to investigate the distribution of lipid and calcium content in culprit lesions assessed by optical coherence tomography (OCT) in patients with PE and explore its relationship with prognosis in a cohort of ST segment elevation myocardial infarction (STEMI) patients.

METHODS

A prospective cohort of 576 patients with STEMI was enrolled in our study. After exclusion, 152 PE patients with clear underlying plaque components were ultimately analysed. The culprit lesion was divided into the border zone, external erosion zone and erosion site in the longitudinal view. Each pullback of the culprit lesions was assessed by 3 independent investigators frame-by-frame, and the quantity and distribution of lipid and calcium components were recorded.

RESULTS

Of the 152 PE patients, lipid and calcium contents were more likely to exist in the external erosion zone than in the other regions. In particular, a high level of lipid content proximal to the erosion site was significantly associated with plaque vulnerability and a higher incidence of MACEs.

CONCLUSION

This study revealed that high level of lipid content in the proximal external erosion zone was related to high-risk plaque characteristics and poor prognosis, which provided a novel method for risk stratification and precise management in patients with plaque erosion.

Association Between Serum Uric Acid Levels and Neoatherosclerosis

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

Multimodality coronary imaging to predict non-culprit territory unrecognized myocardial infarction in Non-ST-Elevation acute coronary syndrome

PURPOSE

Unrecognized myocardial infarction (UMI) detected by cardiac magnetic resonance (CMR) imaging is associated with adverse outcomes in patients with acute and chronic coronary syndrome. This study aimed to assess the predictors of optical coherence tomography (OCT) and coronary computed tomography angiography (CCTA) findings for non-infarct-related (non-IR) territory UMI in patients presenting with non-ST-elevation acute coronary syndrome (NSTE-ACS).

METHODS

We investigated 69 patients with a first clinical episode of NSTE-ACS who underwent pre-percutaneous coronary intervention (PCI) 320-slice CCTA, uncomplicated urgent PCI with OCT assessment within 24 h of admission, and post-PCI CMR. UMI was assessed using late gadolinium enhancement to identify regions of hyperenhancement with an ischemic distribution pattern in non-IR territories.

RESULTS

Non-IR UMI was detected in 11 patients (15.9%). Lower ejection fraction, higher Gensini score, higher Agatston score, high pericoronary adipose tissue attenuation (PCATA), OCT-defined culprit lesion plaque rupture, and OCT-defined culprit lesion cholesterol crystal were significantly associated with the presence of non-IR UMI. On dividing the total cohort was divided into five groups according to the numbers of two OCT-derived risk factors and two CCTA-derived risk factors, the frequency of non-IR UMI frequency significantly increased according to the number of these relevant risk features (p < 0.001). Patients with all of the non-IR UMI risk factors showed 50% prevalence of non-IR UMI, compared with 2.2% of patients with low risk factors (≤ 2).

CONCLUSIONS

Integrated CCTA and culprit lesion OCT assessment may help identify the presence of non-IR UMI, potentially providing prognostic information in patients with first NSTE-ACS episode.

Utility of optical coherence tomography in acute coronary syndromes

Studies utilizing intravascular imaging have replicated the findings of histopathological studies, identifying the most common substrates for acute coronary syndromes (ACS) as plaque rupture, erosion, and calcified nodule, with spontaneous coronary artery dissection, coronary artery spasm, and coronary embolism constituting the less common etiologies. The purpose of this review is to summarize the data from clinical studies that have used high-resolution intravascular optical coherence tomography (OCT) to assess culprit plaque morphology in ACS. In addition, we discuss the utility of intravascular OCT for effective treatment of patients presenting with ACS, including the possibility of culprit lesion-based treatment by percutaneous coronary intervention.

Five-Year Outcomes After Fractional Flow Reserve-Guided Deferral of Revascularization in Infarct-Related Artery Lesions

Background

Little evidence is available about the long-term safety of fractional flow reserve (FFR)-guided deferral of revascularization in infarct-related artery (IRA) lesions, especially when measuring FFR in the late setting after myocardial infarction (MI). This study aimed to assess the long-term outcomes after deferral of revascularization in IRA lesions based on FFR assessed in the late phase of post-MI.

Methods

From the J-CONFIRM registry (Long-Term Outcomes of Japanese Patients With Deferral of Coronary Intervention Based on Fractional Flow Reserve in Multicenter Registry), data on 1447 lesions (1263 patients) were divided into 2 groups: the IRA and non-IRA groups. The primary study end point was the cumulative 5-year incidence of target vessel failure (TVF), such as cardiac death, target vessel-related MI, and clinically driven target vessel revascularization.

Results

Of the 1447 lesions, 138 (9.5%) were classified into the IRA group. The median duration of FFR measurement was 716 days after MI. The frequency of visual-functional mismatches (ie, FFR >0.80 and percent diameter stenosis ≥50% or FFR ≤0.80 and percent diameter stenosis <50%) was comparable between the IRA and non-IRA groups (31.9% vs 36.3%). The cumulative 5-year incidence of TVF did not differ between the groups (9.2% vs 11.8%; inverse probability-weighted hazard ratio, 1.18, 95% confidence intervals, 0.48-2.91, P = .71). Similar results were observed irrespective of regional wall motion assessed by ultrasonic cardiography and acute MI type.

Conclusions

The 5-year TVF rate did not differ between the IRA and non-IRA lesions when deferring revascularization guided by FFR in the late setting of post-MI.

Optical coherence tomography-derived lipid core burden index and clinical outcomes: results from the CLIMA registry

AIMS

The aim of this study was to assess the morphological characteristics and prognostic implications of the optical coherence tomography (OCT)-derived lipid core burden index (LCBI).

METHODS AND RESULTS

OCT-LCBI was assessed in 1003 patients with 1-year follow-up from the CLIMA multicentre registry using a validated software able to automatically obtain a maximum OCT-LCBI in 4 mm (maxOCT-LCBI4mm). Primary composite clinical endpoint included cardiac death, myocardial infarction, and target-vessel revascularization. A secondary analysis using clinical outcomes of CLIMA study was performed. Patients with a maxOCT-LCBI4mm ≥ 400 showed higher prevalence of fibrous cap thickness (FCT) <75 μm [odds ratio (OR) 1.43, 95% confidence interval (CI) 1.03-1.99; P = 0.034], lipid pool arc >180° (OR 3.93, 95%CI 2.97-5.21; P < 0.001), minimum lumen area <3.5 mm2 (OR 1.5, 95%CI 1.16-1.94; P = 0.002), macrophage infiltration (OR 2.38, 95%CI 1.81-3.13; P < 0.001), and intra-plaque intimal vasculature (OR 1.34, 95%CI 1.05-1.72; P = 0.021). A maxOCT-LCBI4mm ≥400 predicted the primary endpoint [adjusted hazard ratio (HR) 1.86, 95%CI 1.1-3.2; P = 0.019] as well as the CLIMA endpoint (HR 2.56, 95%CI 1.24-5.29; P = 0.011). Patients with high lipid content and thin FCT < 75 µm were at higher risk for adverse events (HR 4.88, 95%CI 2.44-9.72; P < 0.001).

CONCLUSIONS

A high maxOCT-LCBI4mm was related to poor outcome and vulnerable plaque features. This study represents a step further in the automated assessment of the coronary plaque risk profile.

Sex-specific features of optical coherence tomography detected plaque vulnerability related to clinical outcomes: insights from the CLIMA study

PURPOSE

To investigate the different impact of optical coherence tomography (OCT)-derived vulnerable plaque features on future adverse events (AEs) according to the biological sex.

METHODS

The prospective multicenter CLIMA study (ClinicalTrials.gov: NCT02883088) enrolled 1003 patients with OCT plaque analysis of non-treated coronary plaques located in the proximal left anterior descending artery. Sex-specific differences in plaque composition and vulnerable features were described. We investigated the incidence of AEs, including cardiac death, any myocardial infarction and target vessel revascularization at 1-year.

RESULTS

Among 1003 patients, 24.6% were women. Women were older and more frequently affected by chronic kidney disease. Dyslipidemia, prior MI and smoking habit were more common in men. At OCT analysis, women had shorter plaque length (p < 0.001), ticker fibrous cap (p = 0.001), smaller maximum lipid arc (p = 0.019), lower macrophage infiltration (p < 0.001) and intra-plaque layered tissue (p = 0.007). During follow-up, 65 AEs were registered. The presence of a thin fibrous cap and a large macrophage infiltration (> 67°) predicted AEs in both sexes. The presence of macrophages (HR 3.38, p = 0.018) and a small minimum lumen area (HR 4.97, p = 0.002) were associated with AEs in women but not in men, while a large lipid arc (> 180°) was associated with AEs in men (HR 2.56, p = 0.003) but not in women.

CONCLUSION

This subanalysis of the CLIMA study investigated for the first-time sex-specific OCT features of plaque vulnerability associated with AEs. Local inflammation was associated with AEs in women and a large lipid arc was predictive in men. OCT may help develop sex-specific risk stratification strategies.

Prognostic Value of Admission Peak NT-proBNP Combined with Culprit Plaque Types for Predicting Cardiovascular Risk in ST-Segment Elevated Myocardial Infarction: An Optical Coherence Tomography Study

OBJECTIVE

Different culprit plaque phenotypes including plaque rupture (PR) and non-plaque rupture (NPR), and N-Terminal prohormone of brain natriuretic peptide (NT-proBNP) have been reported to influence clinical outcomes in patients with acute coronary syndrome (ACS). We aimed to investigate the prognostic implication of the peak and baseline values at admission for NT-proBNP for major adverse cardiovascular events (MACE) in ST-Segment Elevated Myocardial Infarction (STEMI) patients with different plaque phenotype.

METHODS

A total of 428 patients with STEMI undergoing optical coherence tomography (OCT) were enrolled and divided into four groups: PR/Tertile1-2 NT-proBNP (n = 132), PR/Tertile3 NT-proBNP (n = 65), NPR/Tertile1-2 NT-proBNP (n = 154), NPR/Tertlie3 NT-proBNP (n = 77). Baseline and Peak values of NT-proBNP were obtained in the admission period. The MACEs were defined as the composite of all-cause death, recurrence of myocardial infarction and stroke.

RESULTS

High levels for peak NT-proBNP were significantly associated with a higher incidence of MACE and death (Log rank p = 0.037 and 0.0012, respectively). In the subgroup with NPR, a high level for peak NT-proBNP was significantly associated with higher incidence of death (Log rank p = 0.0022) but this association was not significant in the subgroup of PR (Log rank p = 0.24). Though plaque types were not associated with adverse event, the combination of NPR and a higher peak value for NT-proBNP indicated higher incidence of death compared with other groups (Log rank p = 0.0017). The area under the receiver operating characteristic curve for predicting death to evaluate the diagnostic value of the peak value for NT-proBNP and plaque types combined with traditional risk factors was 0.843 (95% CI: 0.805-0.876), which is superior to solely traditional risk factors: NRI (26.8% [95% CI: 0.4-53.1%], p = 0.046) and IDI (5.1% [95% CI: 1.0-9.2%], p = 0.016).

CONCLUSION

STEMI patients with NPR and a high level for peak NT-proBNP showed higher incidence of death. The peak value of NT-proBNP in combination with plaque types can be used in risk stratification and prediction of death in patients with STEMI.

Role of Intracoronary Imaging in Acute Coronary Syndromes

Intravascular imaging with optical coherence tomography (OCT) and intravascular ultrasound provides superior visualization of the culprit plaques for acute coronary syndromes (ACS) compared with coronary angiography. Combined with angiography, intravascular imaging can be used to instigate ‘precision therapy’ for ACS. Post-mortem histopathology identified atherothrombosis at the exposed surface of a ruptured fibrous cap as the main cause of ACS. Further histopathological studies identified intact fibrous caps and calcified nodules as other culprit lesions for ACS. These plaque types were subsequently also identified on intravascular imaging, particularly with the high-resolution OCT. The less-common non-atherothrombotic causes of ACS are coronary artery spasm, coronary artery dissection, and coronary embolism. In this review, the authors provide an overview of clinical studies using intravascular imaging with OCT in the diagnosis and management of ACS.

Major adverse cardiac events after emergency department evaluation of chest pain patients with advanced testing: Systematic review and meta-analysis

OBJECTIVES

Our primary objective was to describe the risk of major adverse cardiac events (MACE) at 1, 6, and 12 months after a negative coronary computed tomography angiogram (cCTA), electrocardiogram (ECG) stress test, stress echocardiography, and myocardial perfusion scintigraphy (MPS) in low- to intermediate-risk patients.

METHODS

Initially, 952 articles were identified for screening, 81 met criteria for full-text review, and once risk of bias was assessed, 33 articles were included in this meta-analysis. We utilized a random-effects model to assess pooled MACE event proportion for patients undergoing evaluation of acute coronary syndrome (ACS) when risk stratified to a low- to intermediate-risk category after undergoing standard testing. Heterogeneity analysis was performed using Cochrane's Q-test and I² statistic.

RESULTS

Twenty-one studies evaluated follow-up at 1 month with cCTA having a 0.09% (95% confidence interval [CI] = 0.03% to 0.26%) pooled MACE compared to 0.23% (95% CI = 0.01% to 5.8%) of the exercise stress testing (p = 1). MPS and cCTA had an overall event rate of 0.15% (95% CI = 0.06% to 0.41%) at 6 months (I²  = 0%). At 12 months, a subgroup analysis found a pooled cCTA MACE of 0.16% (95% CI = 0.04% to 0.65%) compared to 1.68% (95% CI = 0.01% to 2.6%) for stress echocardiography with low within-group heterogeneity (I²  = 0%). Subgroup analysis of cCTA with no disease versus nonobstructive disease (<50% stenosis) did not find statistical difference in the MACE at both 1 month (0.17% [95% CI = 0.04% to 0.67%] vs. 0.06% [95% CI = 0.01% to 0.34%]) and 12 months (0.44% [95% CI = 0.09% to 2.2% vs. 0.54% [95% CI = 0.19% to 1.5%]).

CONCLUSIONS

Patients presenting with chest pain who have a coronary CTA showing < 50% stenosis, negative ECG stress test, stress echocardiography, or stress myocardial perfusion scan in the past 12 months can be discharged without any further risk stratification if their ECG and troponin are reassuring given low MACE.

Assessment of radial artery atherosclerosis in acute coronary syndrome patients: an in vivo study using optical coherence tomography

Background

Radial artery (RA) atherosclerosis in acute coronary syndrome (ACS) patients has not been systematically observed in vivo. The study aims to characterize plaque morphology and intimal hyperplasia of the RA in patients with ACS, using optical coherence tomography (OCT).

Methods

In this retrospective study involving 239 ACS patients underwent RA OCT without guidewire shadow, 3 groups were divided according to the following criteria: radial artery plaque (RAP) group included patients with fibrous, lipid or calcified plaque; patients without RAP were further classified into radial intimal hyperplasia (RIH) group (intima media thickness ratio [IMR] ≥ 1) or normal group (IMR < 1). The presence and characteristics of RAP and its related risk factors were identified.

Results

The RAP, RIH and normal groups included 76 (31.8%), 69 (28.9%) and 94 (39.3%) patients, respectively. Patients in RAP group were the oldest, compared with those in the RIH and normal groups (p < 0.001), and more frequently had triple vessel disease (p = 0.004). The percentage of plaque rupture (72.4% vs. 56.4%, p = 0.018) and calcification (42.1% vs. 27.6%, p = 0.026) at culprit lesion were significantly higher in patients with RAP than those without RAP. A total of 148 RAP were revealed by OCT, including fibrous (72, 48.6%), lipid (50, 33.8%) and calcified plaques (26, 17.6%). The microvessels were also frequently observed in the RAP group than that in RIH and normal groups (59.2% vs. 8.7% vs. 9.6%, p < 0.001). Multivariate logistic regression analysis showed that age, diabetes, and smoking history (all p < 0.05) were independent risk factors for RAP.

Conclusions

In terms of insights gained from OCT, RA atherosclerosis is not uncommon in ACS patients by OCT, sharing several morphological characters with early coronary atherosclerosis. Aging, diabetes, and smoking are risk factors for RAP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02561-5.

What Is Hidden Behind Yellow Pixels: from Pathology to Intravascular Imaging of Atherosclerotic Plaque

PURPOSE OF REVIEW

Intravascular imaging systems can identify lipid-rich and vulnerable plaques and help in treatment guidance. The comparability of different intracoronary imaging methods remains unclear. In this paper, we review atherosclerotic plaque pathology, plaque-stabilising effects of different lipid-lowering therapies and usage of intravascular imaging modalities. We present the results of our study in which we evaluated the correlation of the intravascular ultrasound iMAP system (iMAP-IVUS) and near-infrared spectroscopy (NIRS) in the diagnosis of vulnerable coronary plaques.

RECENT FINDINGS

Lipids have an essential contribution to plaque evolution and vulnerability. Increase in plaque vulnerability alone even without increase in plaque burden defines progression of atherosclerosis. Lipidic tissue has a significant diagnostic value in patient risk stratification and can serve as a treatment target. Different vulnerable plaque parameters can be visualised with iMAP-IVUS and NIRS. Intravascular imaging systems can differ with regard to their sensitivity, specificity and limitations. Lipid-lowering therapy is crucial in plaque stabilisation.

Morphological Characteristics of Eroded Plaques with Noncritical Coronary Stenosis: An Optical Coherence Tomography Study

AIMS

Recent studies suggested plaque erosion with noncritical stenosis could be treated distinctly from that with critical stenosis, but their morphological features remained largely unknown. The present study aimed to investigate morphological features of eroded plaques with different lumen stenosis using optical coherence tomography (OCT).

METHODS

A total of 348 ST-segment elevated myocardial infarction patients with culprit OCT-defined plaque erosion (OCT-erosion) were analyzed. Based on the severity of lumen area stenosis, all patients with OCT-erosions were divided into the following three groups: Group A (area stenosis ＜50%, n=50); Group B (50% ≤ area stenosis ＜75%, n=146); Group C (area stenosis ≥ 75%, n=152).

RESULTS

Compared with patients in Groups A and B, patients in Group C were older (p=0.008) and had higher prevalence of hypertension (p=0.029). Angiographic analysis showed that 72.0% of the eroded plaques in Group A were located in the left anterior descending artery, followed by 67.8% in Group B, and 53.9% in Group C (p=0.039). OCT analysis showed that Group A had the highest prevalence of fibrous plaques (p＜0.001) and nearby bifurcation (p=0.036), but the lowest prevalence of lipid-rich plaques (p＜0.001), macrophage accumulation (p＜0.001), microvessels (p=0.009), cholesterol crystals (p＜0.001), and calcification (p=0.023). Multivariable regression analysis showed fibrous plaque (odds ratio [OR]: 3.014, 95% confidence interval [CI]: 1.932-4.702, p＜0.001) and nearby bifurcation (OR: 1.750, 95% CI: 1.109-2.761, p=0.016) were independently associated with OCT-erosion with an area stenosis of ＜75%.

CONCLUSIONS

More than half of OCT-erosions presented with ＜75% area stenosis, having distinct morphological features from those of OCT-erosions with critical stenosis. Fibrous plaque and nearby bifurcation were independently associated with noncritically stenotic OCT-erosion, suggesting that eroded plaques might need individualized treatment.

Coronary plaque and clinical characteristics of South Asian (Indian) patients with acute coronary syndromes: An optical coherence tomography study

BACKGROUND

South Asians, and Indians in particular, are known to have a higher incidence of premature atherosclerosis and acute coronary syndromes (ACS) with worse clinical outcomes, compared to populations with different ethnic backgrounds. However, the underlying pathobiology accounting for these differences has not been fully elucidated.

METHODS

ACS patients who had culprit lesion optical coherence tomography (OCT) imaging were enrolled. Culprit plaque characteristics were evaluated using OCT.

RESULTS

Among 1315 patients, 100 were South Asian, 1009 were East Asian, and 206 were White. South Asian patients were younger (South Asians vs. East Asians vs. Whites: 51.6 ± 13.4 vs. 65.4 ± 11.9 vs. 62.7 ± 11.7; p < 0.001) and more frequently presented with ST-segment elevation myocardial infarction (STEMI) (77.0% vs. 56.4% vs. 35.4%; p < 0.001). On OCT analysis after propensity group matching, plaque erosion was more frequent (57.0% vs. 38.0% vs. 50.0%; p = 0.003), the lipid index was significantly greater (2281.6 [1570.8-3160.6] vs. 1624.3 [940.9-2352.4] vs. 1303.8 [1090.0-1757.7]; p < 0.001), and the prevalence of layered plaque was significantly higher in the South Asian group than in the other two groups (52.0% vs. 30.0% vs. 34.0%; p = 0.003).

CONCLUSIONS

Compared to East Asians and Whites, South Asians with ACS were younger and more frequently presented with STEMI. Plaque erosion was the predominant pathology for ACS in South Asians and their culprit lesions had more features of plaque vulnerability.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov, NCT03479723.

Age and Phenotype of Patients With Plaque Erosion

Background

A recent study reported that the outcome of patients with plaque erosion treated with stenting is poor when the underlying plaque is lipid rich. However, the detailed phenotype of patients with plaque erosion, particularly as related to different age groups, has not been systematically studied.

Methods and Results

Patients with acute coronary syndromes caused by plaque erosion were selected from 2 data sets. Demographic, clinical, angiographic, and optical coherence tomography findings of the culprit lesion were compared between 5 age groups. Among 579 erosion patients, male sex and current smoking were less frequent, and hypertension, diabetes, and chronic kidney disease were more frequent in older patients. ST‐segment–elevation myocardial infarction was more frequent in younger patients. Percentage of diameter stenosis on angiogram was greater in older patients. The prevalence of lipid‐rich plaque (27.3% in age <45 years and 49.4% in age ≥75 years, P<0.001), cholesterol crystal (3.9% in age <45 years and 21.8% in age ≥75 years, P=0.027), and calcification (5.5% in age <45 years and 54.0% in age ≥75 years, P<0.001) increased with age. After adjusting risk factors, younger patients were associated with the presence of thrombus, and older patients were associated with greater percentage of diameter stenosis and the presence of lipid‐rich plaque and calcification.

Conclusions

The demographic, clinical, angiographic, and plaque phenotypes of patients with plaque erosion distinctly vary depending on age. This may affect the clinical outcome in these patients.

Registration

URL: https://www.clinicaltrials.gov. Unique identifiers: NCT03479723, NCT02041650.

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.

Optical Coherence Tomography in Acute Coronary Syndromes

Advances in intravascular imaging have enabled assessment of the underlying plaque morphology in acute coronary syndromes, which allows for the initiation of individualized therapy. The atherothrombotic substrates for acute coronary syndromes consist of plaque rupture, erosion, and calcified nodule, whereas spontaneous coronary artery dissection, coronary artery spasm, and coronary embolism constitute rarer nonatherothrombotic etiologies. This review provides a brief overview of the data from clinical studies that have used intravascular optical coherence tomography to assess the culprit plaque morphology. We discuss the usefulness of intravascular imaging for effective treatment of patients presenting with acute coronary syndromes by percutaneous coronary intervention.

Combined coronary CT angiography with plain scan for diagnosis of ruptured plaque: comparison with optical coherence tomography

To evaluate the diagnostic efficacy of CCTA + plain scan for ruptured plaques, with optical coherence tomography (OCT) as the reference, and to provide preliminary analysis of influential factors. Patients who underwent CCTA and OCT were retrospectively enrolled. The diagnostic standards for ruptured plaque on CCTA + plain scan were ulcer or intra-plaque dye penetration on CCTA, and a careful review of images from the plain scans to ensure areas of them were not calcification. The diagnosis of ruptured plaque was made by OCT. Total 65 patients with 71 plaques were included. There were 40 OCT-confirmed ruptured plaques in 38 patients and 31 OCT-confirmed non-ruptured plaques in 27 patients. CCTA + plain scan identified 27 ruptured plaques in 27 patients and 28 non-ruptured plaques in 24 patients. With OCT as the gold standard, the per-patient sensitivity, specificity, positive and negative predictive values, and accuracy of CCTA + plain scan for diagnosing ruptured plaque were 71%, 89%, 90%, 69%, and 78%, and there was good agreement (Kappa = 0.70) between CCTA + plain scan and OCT. Among 13 false negative ruptured plaques, 2 had calcifications close to the rupture, and the cavity depth in the remaining 11 was 0.46 ± 0.17 mm, versus 0.98 ± 0.26 mm in 27 true positive ruptured plaques (P < 0.01). CCTA + plain scan may identify morphological features of ruptured plaques. The cavity depth of the ruptured plaques and calcification at the rupture site seem major factors influencing the diagnostic accuracy for plaque rupture. Future perspective studied are needed to confirm these preliminary findings.

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 .

Advances in IVUS/OCT and Future Clinical Perspective of Novel Hybrid Catheter System in Coronary Imaging

Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have been developed and improved as both diagnostic and guidance tools for interventional procedures over the past three decades. IVUS has a resolution of 100 μm with a high tissue penetration and capability of assessing the entire structure of a coronary artery including the external elastic membrane, whereas OCT has a higher resolution of 10–20 μm to assess endoluminal structures with a limited tissue penetration compared to IVUS. Recently, two companies, CONAVI and TERUMO, integrated IVUS and OCT into a single catheter system. With their inherent strength and limitations, the combined IVUS and OCT probes are complementary and work synergistically to enable a comprehensive depiction of coronary artery. In this review, we summarize the performance of the two intracoronary imaging modalities—IVUS and OCT—and discuss the expected potential of the novel hybrid IVUS–OCT catheter system in the clinical field.

Sex Differences in Coronary Artery Calcium and Long-term CV Mortality

PURPOSE OF REVIEW

To summarize differences in plaque depositions, coronary artery calcium (CAC) scoring, and the role of CAC in predicting atherosclerotic cardiovascular disease (ASCVD) mortality in men and women.

RECENT FINDINGS

Women have coronary plaque that is more lipid-rich, dense, and less calcified than their male counterparts. CAC scoring has emerged as a useful tool to quantify ASCVD burden. However, recent evidence favors the use of sex-adjusted CAC cutoffs for women to account for the relatively lower overall CAC burden and therefore risk stratify women appropriately. Several studies have identified CAC distribution patterns in women associated with increased CV mortality, particularly the number of lesions involved, CAC volume, and size. Multiple studies have shown that the pathophysiology and associated risks of ASCVD are different in women when compared with men. CAC scoring is a tool that is widely being used for ASCVD risk stratification. Recent studies have shown that although men have higher CAC burdens, women are more likely to develop plaque erosions with non-calcified plaque that carries a greater risk for cardiovascular events. Providers should be aware of sex-specific CAC patterns carrying increased mortality risk for women, particularly increasing lesion size and number. Given the differences in plaque composition and distribution, revised sex-adjusted CAC scoring is suggested to better risk stratify patients, especially those deemed intermediate risk, and decrease CV mortality.

Two distinct phenotypes of plaque erosion assessed by multimodality intracoronary imaging: a case series

Background 

Pathological studies have reported that patients with acute coronary syndrome (ACS) may have different plaque morphologies at culprit lesions, and one of the underlying mechanisms for ACS is plaque erosion. However, the morphological features of plaque erosion obtained by multiple intracoronary imaging modalities have not been fully elucidated.

Case summary 

We experienced two cases with ACS of culprit lesions exhibiting optical coherence tomography (OCT)-defined plaque erosion. Additional examinations using near-infrared spectroscopy (NIRS)–intravascular ultrasound and coronary angioscopy suggested the presence of two distinct phenotypes of plaque erosion. These two types of erosion differ in the extent of NIRS-derived lipid core burden and coronary angioscopy-derived luminal surface colour.

Discussion 

OCT-defined plaque erosion may not be the unique entity but have at least two distinct plaque morphologies, and NIRS and/or coronary angioscopy may provide incremental ability of discriminating these plaque phenotypes classified as plaque erosion by OCT.