Plaque microstructures in patients with coronary artery disease who achieved very low low-density lipoprotein cholesterol levels

Influence of metabolic syndrome on plaque features and clinical outcomes in patients with acute coronary syndrome

BACKGROUND AND AIMS

Currently, the influence of metabolic syndrome (Mets) on the plaque characteristics and prognosis of patients with acute coronary syndrome (ACS) is poorly understood. Thus, the study aimed to characterize the pancoronay plaques of ACS patients with Mets using optical coherence tomography (OCT) and to evaluate the cohort's prognosis.

METHODS

Between February 2015 and September 2020, 745 ACS patients who underwent OCT imaging of the three coronary arteries were included, divided into Mets (n = 252) and non-Mets (n = 493) groups. The major adverse cardiovascular event (MACE) was a composite of cardiac death, non-fatal myocardial infarction (MI), and revascularization.

RESULTS

Compared to the non-Mets group, the Mets group exhibited a higher proportion of females and cases of multivessel disease. In the Mets group, culprit lesions were found to have a greater degree of stenosis, thinner fibrous cap thickness and more thin-cap fibroatheroma (TCFA). Additionally, nonculprit lesions were more likely to exhibit plaque rupture, high-risk plaque characteristics, TCFA, macrophage infiltration, cholesterol crystals, and layered plaque. After a median follow-up of 2 years, 8.3% of patients experienced MACE, a rate that was higher in the Mets group, primarily attributed to non-fatal myocardial infarction and cardiac death. Multivariate analysis showed that Mets (aHR 1.73, p = 0.037), high-risk plaque (aHR 2.63, p < 0.001), age (aHR 1.03, p = 0.020), and left ventricular ejection fraction (aHR 0.96, p = 0.002) were independent predictors of MACE.

CONCLUSIONS

The presence of Mets increased the vulnerability of the entire coronary tree and worsened the prognosis for patients with ACS.

Adjunctive PCSK9 Inhibitor Evolocumab in the Prevention of Early Neurological Deterioration in Non-cardiogenic Acute Ischemic Stroke: A Multicenter, Prospective, Randomized, Open-Label, Clinical Trial

BACKGROUND

Early neurological deterioration (END) is associated with a poor prognosis in acute ischemic stroke (AIS). Effectively lowering low-density lipoprotein cholesterol (LDL-C) can improve the stability of atherosclerotic plaque and reduce post-stroke inflammation, which may be an effective means to lower the incidence of END. The objective of this study was to determine the preventive effects of evolocumab on END in patients with non-cardiogenic AIS.

METHODS

This was a multicenter, prospective, open-label, blinded-endpoint clinical trial. Participants with AIS within 24 h were randomly assigned to either the group receiving combination therapy of evolocumab and atorvastatin, which is a 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase inhibitor, i.e., a "statin" (PI group), or the group receiving atorvastatin monotherapy (AT group). The primary outcome was END within 7 days, defined as a 2-point increase in the National Institutes of Health Stroke Scale (NIHSS) score or a 1-point increase in motor function within 24 h-7 days from the onset of AIS. Secondary outcomes included LDL-C target achievement rate on day 7 (≤ 1.8 mmol/L with a reduction exceeding 50% from baseline), inflammatory factors (interleukin [IL]-6, IL-8, and tumor necrosis factor [TNF]-α) before and after 7 days of treatment, and stroke-related death with 7 days. Safety endpoints included any adverse events.

RESULTS

Patients with AIS (n = 272) were randomly assigned to the PI (n = 136) or AT (n = 136) groups. Within 7 days, 18 (13.2%) and 33 (24.3%) patients experienced END in the PI and AT groups, respectively (relative risk [RR] -0.90; 95% confidence interval [CI]: -1.59 to -0.22; p = 0.010). On the seventh day, LDL-C target achievement rate in the PI and AT groups was 74.3% and 14.7%, respectively (RR 3.27; 95% CI: 2.40-4.15; p = 0.001). Changes in IL-6 over 7 days were significantly lower in the PI group compared with the AT group, respectively (median 1.02 [range -1.91, 5.47] versus 2.54 [-0.83, 15.20]; p = 0.033). On the 90th day of follow-up, 83.1% and 65.4% of patients had a modified Rankin Scale score ≤ 2 in the PI and AT groups, respectively (RR 0.51; 95% CI: 0.66-2.66; p = 0.001). There was no significant difference in stroke recurrence between the two groups within 90 days (RR -1.72; 95% CI: -4.57 to 1.13; p = 0.237). Regarding adverse events, 15 and 22 patients in the PI and AT groups, respectively, experienced slight abnormalities in liver and kidney function laboratory values during the 7-day treatment period (odds ratio 0.62; 95% CI: 0.30-1.29; p = 0.203), but no serious adverse events were observed in either group.

CONCLUSION

These results suggest that the combination therapy of evolocumab and atorvastatin within 24 h of AIS onset may effectively reduce the incidence of END compared with atorvastatin monotherapy. Additionally, in the early stages of AIS, this combination therapy can reduce blood LDL-C levels, and inhibit IL-6 elevation, potentially improving the prognosis of patients with AIS within 90 days.

TRIAL REGISTRATION

China Clinical Trials Registry (No: ChicTR2200059445, 29 April 2022, https://www.chictr.org.cn/ ).

[Rationale for Increasing Doses of Statins in Everyday Clinical Practice]

HMG-CoA reductase inhibitors (statins) were discovered in the early 1970s in Japan and were originally used to treat patients with hereditary hyperlipidemia. In the late 1990s and early 2000s, clinical trials using statins for primary and secondary prevention showed the possibility of reducing cardiovascular (CV) and, in some cases, all-cause mortality. Intensive statin therapy (atorvastatin 80 mg/day and rosuvastatin 40 mg/day) compared to initial doses provides an additional 16% reduction in CV complications. Regression studies with the original rosuvastatin using intracoronary ultrasound and other modern methods have shown the possibility of stabilization and regression of atherosclerosis in the carotid and coronary arteries. High-dose statin therapy is generally well tolerated; the incidence of clinically significant adverse liver reactions does not exceed 2-3 per 100,000 people, and the incidence of myopathies with increased creatine kinase over 10 upper limits of normal is not higher than 1 per 10,000 people per year. Long-term statin treatment does not increase the risk of dementia and, in some studies, reduced the risk of Alzheimer's disease. Achieving target levels of low-density lipoprotein cholesterol (LDL-C) in routine practice does not exceed 5-11%; one of the main reasons for that is the rare (2-3%) prescription of high doses of statins. Increasing statin doses in routine clinical practice will optimize the treatment of patients with high CV risk and will contribute to further reduction of mortality in our country.

The impact of statins treatments for plaque characteristics in stable angina pectoris patients with very low and high low-density lipoprotein cholesterol levels: an intracoronary optical coherence tomography study

Low-density lipoprotein cholesterol (LDL-C) levels are recommended according to the patient's risk factors based on guidelines. In patients achieving low LDL-C levels, the need for statins is uncertain, and the plaque characteristics of patients not treated with statins are unclear. In addition, the difference in plaque characteristics with and without statins is unclear in similarly high LDL levels. We evaluate the impact of statins on plaque characteristics on optical coherence tomography (OCT) in patients with very low LDL-C levels and high LDL-C levels. A total of 173 stable angina pectoris patients with 173 lesions undergoing OCT before percutaneous coronary intervention were evaluated. We divided the LDL-C levels into three groups: < 70 mg/dL (n = 48), 70 mg/dL ≤ LDL-C < 100 mg/dL (n = 71), and ≥ 100 mg/dL (n = 54). Among patients with LDL-C < 70 mg/dL, patients not treated with statins showed a significantly higher C-reactive protein level (0.27 ± 0.22 mg/dL vs. 0.15 ± 0.19 mg/dL, p = 0.049), and higher incidence of thin-cap fibroatheromas (TCFAs; 44% [7/16] vs. 13% [4/32], p = 0.021) than those treated with statins. Among patients with LDL-C level ≥ 100 mg/dL, patients treated with statins showed a significantly higher prevalence of familial hypercholesterolemia (FH) (38% [6/16] vs. 5% [2/38], p = 0.004), lower incidence of TCFAs (6% [1/16] vs. 39% [15/38], p = 0.013), healed plaques (13% [2/16] vs. 47% [18/38], p = 0.015), and higher incidence of fibrous plaques (75% [12/16] vs. 42% [16/38], p = 0.027) than patients not treated with statins. While patients achieved a low LDL-C, patients not treated with statins had high plaque vulnerability and high systemic inflammation. While patients had a high LDL-C level with a high prevalence of FH, patients treated with statins had stable plaque characteristics.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

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

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

Effect of evolocumab on the progression of intraplaque neovascularization of the carotid based on contrast-enhanced ultrasonography (EPIC study): A prospective single-arm, open-label study

Background and Purpose: The aim of this study was to explore the effect of half a year of evolocumab plus moderate-intensity statin treatment on carotid intraplaque neovascularization (IPN) and blood lipid levels. Methods: A total of 31 patients with 33 carotid plaques who received evolocumab plus statin treatment were included. Blood lipid levels, B-mode ultrasound and contrast-enhanced ultrasonography (CEUS) at baseline and after half a year of evolocumab plus statin therapy were collected. The area under the curve (AUC) reflected the total amount of acoustic developer entering the plaque or lumen within the 180 s measurement period. The enhanced intensity reflected the peak blood flow intensity during the monitoring period, and the contrast agent area reflected the area of vessels in the plaques. Results: Except for high-density lipoprotein cholesterol (HDL-c), all other lipid indices decreased. Compared with baseline, low-density lipoprotein cholesterol (LDL-c) decreased by approximately 57% (p < 0.001); total cholesterol (TC) decreased by approximately 34% (p < 0.001); small dense low-density lipoprotein (sd-LDL) decreased by approximately 52% (p < 0.001); and HDL-c increased by approximately 20% (p < 0.001). B-mode ultrasonography showed that the length and thickness of the plaque and the hypoechoic area ratio were reduced (p < 0.05). The plaque area, calcified area ratio, and lumen cross-sectional area changed little (p > 0.05). CEUS revealed that the area under the curve of plaque/lumen [AUC (P/L)] decreased from 0.27 ± 0.13 to 0.19 ± 0.11 (p < 0.001). The enhanced intensity ratio of plaque/lumen [intensity ratio (P/L)] decreased from 0.37 ± 0.16 to 0.31 ± 0.14 (p = 0.009). The contrast agent area in plaque/area of plaque decreased from 19.20 ± 13.23 to 12.66 ± 9.59 (p = 0.003). The neovascularization score decreased from 2.64 ± 0.54 to 2.06 ± 0.86 (p < 0.001). Subgroup analysis based on statin duration (<6 months and ≥6 months) showed that there was no significant difference in the AUC (P/L) or intensity ratio (P/L) at baseline or after half a year of evolocumab treatment. Conclusion: This study found that evolocumab combined with moderate-intensity statins significantly improved the blood lipid profile and reduced carotid IPN. Clinical Trial Registration: https://www.clinicaltrials.gov; identifier: NCT04423406.

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

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

Detection of Vulnerable Coronary Plaques Using Invasive and Non-Invasive Imaging Modalities

Acute coronary syndrome (ACS) mostly arises from so-called vulnerable coronary plaques, particularly prone for rupture. Vulnerable plaques comprise a specific type of plaque, called the thin-cap fibroatheroma (TFCA). A TCFA is characterized by a large lipid-rich necrotic core, a thin fibrous cap, inflammation, neovascularization, intraplaque hemorrhage, microcalcifications or spotty calcifications, and positive remodeling. Vulnerable plaques are often not visible during coronary angiography. However, different plaque features can be visualized with the use of intracoronary imaging techniques, such as intravascular ultrasound (IVUS), potentially with the addition of near-infrared spectroscopy (NIRS), or optical coherence tomography (OCT). Non-invasive imaging techniques, such as computed tomography coronary angiography (CTCA), cardiovascular magnetic resonance (CMR) imaging, and nuclear imaging, can be used as an alternative for these invasive imaging techniques. These invasive and non-invasive imaging modalities can be implemented for screening to guide primary or secondary prevention therapies, leading to a more patient-tailored diagnostic and treatment strategy. Systemic pharmaceutical treatment with lipid-lowering or anti-inflammatory medication leads to plaque stabilization and reduction of cardiovascular events. Additionally, ongoing studies are investigating whether modification of vulnerable plaque features with local invasive treatment options leads to plaque stabilization and subsequent cardiovascular risk reduction.

Plaque microstructures during metformin therapy in type 2 diabetic subjects with coronary artery disease: optical coherence tomography analysis

BACKGROUND

While metformin is recommended as a first-line cardioprotective therapy for type 2 diabetic patients, whether it exerts direct effects on atherosclerotic plaque remains uncertain. The current study characterized coronary plaque microstructures in type 2 diabetic patients who received metformin.

METHODS

We retrospectively analyzed 409 non-culprit lipid plaques in 313 type 2 diabetic patients with coronary artery disease (CAD) by using frequency-domain optical coherence tomography (FD-OCT) imaging. FD-OCT derived plaque microstructures were compared in patients stratified according to metformin use.

RESULTS

A proportion of 38.6% of study subjects received metformin. Patients receiving metformin more likely exhibited a history of hypertension (79.3% vs. 67.1%, P=0.03) and metabolic syndrome (52.8% vs. 36.4%, P=0.01). On FD-OCT imaging, the prevalence of lipid plaque was lower in the metformin group (66.2% vs. 77.9%, P=0.03). Furthermore, the metformin group demonstrated plaques with a smaller lipid arc (median: 168.7° vs. 208.5°, P=0.008), shorter longitudinal length (media: 5.1 vs. 9.1 mm, P=0.04), and a lower frequency of cholesterol crystal (3.9% vs. 18.2%, P=0.01) and spotty calcification (3.9% vs. 34.8%, P=0.008). These differences remained significant after adjusting for clinical characteristics and glycemic control. However, in patients who received insulin, the favourable effect of metformin on lipid arc was not observed (insulin user: P=0.87; insulin non-user: P=0.009; P value for interaction between two groups, P=0.02).

CONCLUSIONS

Metformin use was associated with a lower prevalence of vulnerable plaque features in type 2 diabetic patients with CAD, especially insulin non-user. These findings suggest the potential of metformin to exert direct plaque stabilization effects in type 2 diabetic subjects.

Potential of optical coherence tomography and intravascular ultrasound in the detection of vulnerable plaques in coronary arteries

Intravascular imaging of vulnerable plaques in vivo has great potential for predicting coronary events. Currently, there are several methods of intravascular imaging, which make it possible to verify the components of the plaque and, accordingly, its vulnerability. The most common are virtual-histology intravascular ultrasound and optical coherence tomography. Several studies have shown that these imaging techniques can stratify the risk of adverse cardiovascular events, as well as assess the effectiveness of drug therapy. This article will describe the advantages and disadvantages of intravascular ultrasound and optical coherence tomography in identifying vulnerable coronary lesions.

Lower levels of low-density lipoprotein cholesterol are associated with a lower prevalence of thin-cap fibroatheroma in statin-treated patients with coronary artery disease

BACKGROUND

Reducing low-density lipoprotein cholesterol (LDL-C) levels with statins slows the progression of atherosclerotic plaques and reduces cardiovascular events. The 2019 European Society of Cardiology/European Atherosclerosis Society guidelines recommend absolute LDL-C treatment targets of <100 mg/dL, <70 mg/dL and <55 mg/dL according to coexisting patient risk factors.

OBJECTIVE

To clarify the difference in the plaque characteristics of coronary lesions associated with these LDL-C levels in statin-treated patients.

METHODS

A total of 685 consecutive statin-treated patients with coronary artery disease (CAD) who underwent optical coherence tomography (OCT) imaging of culprit lesions were enrolled. The characteristics of culprit plaques evaluated by OCT were compared among the high LDL-C group (≥100 mg/dL, n=247), the moderate LDL-C group (70-100 mg/dL, n=289), the low LDL-C group (55-70 mg/dL, n=106) and the very low LDL-C group (<55 mg/dL, n=43).

RESULTS

A significant trend toward a lower prevalence of thin-cap fibroatheroma (TCFA) associated with the LDL-C groups was observed (23.1, 18.3, 9.4 and 11.6%, respectively, in each group; p=0.002). A trend toward a lower prevalence of TCFAs associated with the LDL-C groups was also observed among patients with lower hemoglobin A1c (<6.2%; p=0.003). LDL-C <70 mg/dL (the low/very low group) was independently associated with the lack of TCFAs (odds ratio, 0.50; 95% confidence interval, 0.27-0.87, p=0.014).

CONCLUSIONS

Lower LDL-C levels were associated with a lower prevalence of TCFAs in culprit plaques among statin-treated patients with CAD.

The impact of lipid-lowering medications on coronary artery plaque characteristics

Atherosclerosis is the predominant cause of coronary artery disease. The last several decades have witnessed significant advances in lipid-lowering therapies, which comprise a central component of atherosclerotic cardiovascular disease prevention. In addition to cardiovascular risk reduction with dyslipidemia management, some lipid-based therapies show promise at the level of the atherosclerotic plaque itself through mechanisms governing lipid accumulation, plaque stability, local inflammation, endothelial dysfunction, and thrombogenicity. The capacity of lipid-lowering therapies to modify atherosclerotic plaque burden, size, composition, and vulnerability should correlate with their ability to reduce disease progression. This review discusses plaque characteristics, diagnostic modalities to evaluate these characteristics, and how they are altered by current and emerging lipid-lowering therapies, all in human coronary artery disease.

Vulnerable atherosclerotic plaque features: findings from coronary imaging

Pathological studies have suggested that features of vulnerable atherosclerotic plaques likely to progress and lead to acute cardiovascular events have specific characteristics. Given the progress of intravascular coronary imaging technology, some large prospective studies have detected features of vulnerable atherosclerotic plaques using these imaging modalities. However, the rate of cardiovascular events, such as acute coronary syndrome, has been found to be considerably reduced in the limited follow-up period available in the statin era. Additionally, not all disrupted plaques lead to thrombus formation with clinical presentation. If sub-occlusive or occlusive thrombus formation does not occur, a thrombus on a disrupted plaque will organize without any symptoms, forming a "healed plaque". Although vulnerable plaque detection using intracoronary imaging is focused on "thin-cap fibroatheroma" leading to plaque rupture, superficial plaque erosion is increasingly recognized; however, the underlying mechanism of thrombus formation on eroded plaques is not well understood. One of intravascular imaging, optical coherence tomography (OCT) has the highest image resolution and has enabled detailed characterization of the plaque in vivo. Here, we reviewed the status and limitations of intravascular imaging in terms of detecting vulnerable plaque through mainly OCT studies. We suggested that vulnerable plaque should be reconsidered in terms of eroded plaque and healed plaque and that both plaque and circulating blood should be assessed in greater detail accordingly.

Low-density lipoproteins cause atherosclerotic cardiovascular disease: pathophysiological, genetic, and therapeutic insights: a consensus statement from the European Atherosclerosis Society Consensus Panel

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Intensive statin versus low-dose statin + ezetimibe treatment for fibrous cap thickness of coronary vulnerable plaques

BACKGROUND

Acute coronary syndromes mainly result from abrupt thrombotic occlusion caused by atherosclerotic vulnerable plaques (VPs) that suddenly rupture or erosion. Fibrous cap thickness (FCT) is a major determinant of the propensity of a VP to rupture and is recognized as a key factor. The intensive use of statins is known to have the ability to increase FCT; however, there is a risk of additional adverse effects. However, lower dose statin with ezetimibe is known to be tolerable by patients. The present study aimed to investigate the effect of intensive statin vs. low-dose stain + ezetimibe therapy on FCT, as evaluated using optical coherence tomography.

METHOD

Patients who had VPs (minimum FCT <65 μm and lipid core >90°) and deferred from intervention in our single center from January 2014 to December 2018 were included in the trial. They were divided into the following two groups: intensive statin group (rosuvastatin 15-20 mg or atorvastatin 30-40 mg) and combination therapy group (rosuvastatin 5-10 mg or atorvastatin 10-20 mg + ezetimibe 10 mg). At the 12-month follow-up, we compared the change in the FCT (ΔFCT%) between the two groups and analyzed the association of ΔFCT% with risk factors. Fisher exact test was used for all categorical variables. Student's t test or Mann-Whitney U-test was used for analyzing the continuous data. The relationship between ΔFCT% and risk factors was analyzed using linear regression analysis.

RESULT

Total 53 patients were finally enrolled, including 26 patients who were in the intensive statin group and 27 who were in the combination therapy group. At the 12-month follow-up, the serum levels of total cholesterol (TC), total triglyceride, low-density lipoprotein (LDL-C), hypersensitive C-reactive protein (hs-CRP), and lipoprotein-associated phospholipase A2 (Lp-PLA2) levels were reduced in both the groups. The ΔTC%, ΔLDL-C%, and ΔLp-PLA2% were decreased further in the combination therapy group. FCT was increased in both the groups (combination treatment group vs. intensive statin group: 128.89 ± 7.64 vs. 110.19 ± 7.00 μm, t = -9.282, P < 0.001) at the 12-month follow-up. The increase in ΔFCT% was more in the combination therapy group (123.46% ± 14.05% vs. 91.14% ± 11.68%, t = -9.085, P < 0.001). Based on the multivariate linear regression analysis, only the serum Lp-PLA2 at the 12-month follow-up (B = -0.203, t = -2.701, P = 0.010), ΔTC% (B = -0.573, t = -2.048, P = 0.046), and Δhs-CRP% (B = -0.302, t = -2.963, P = 0.005) showed an independent association with ΔFCT%.

CONCLUSIONS

Low-dose statin combined with ezetimibe therapy maybe provide a profound and significant increase in FCT as compared to intensive statin monotherapy. The reductions in Lp-PLA2, ΔTC%, and Δhs-CRP% are independently associated with an increase in FCT.

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

Background

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

Methods

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

Results

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

Conclusions

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

Trial registration

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

In vivo imaging of vulnerable plaque with intravascular modalities: its advantages and limitations

In vivo imaging of plaque instability has been considered to have a great potential to predict future coronary events and evaluate the stabilization effect of novel anti-atherosclerotic medical therapies. Currently, there are several intravascular imaging modalities which enable to visualize plaque components associated with its vulnerability. These include virtual histology intravascular ultrasound (VH-IVUS), integrated backscatter IVUS (IB-IVUS), optical coherence tomography (OCT), near-infrared spectroscopy and coronary angioscopy. Recent studies have shown that these tools are applicable for risk stratification of cardiovascular events as well as drug efficacy assessment. However, several limitation exists in each modality. The current review paper will outline advantages and limitation of VH-IVUS, IB-IVUS, OCT, NIRS and coronary angioscopy imaging.

The efficacy of glycemic control with continuous glucose monitoring on atheroma progression: rationale and design of the Observation of Coronary Atheroma Progression under Continuous Glucose Monitoring Guidance in Patients with Type 2 Diabetes Mellitus (OPTIMAL)

Background

Patients with type 2 diabetes mellitus (T2DM) are high-risk subjects who more frequently have micro- and macrovascular diseases including coronary artery disease (CAD). Since impaired glycemic homeostasis directly influences the formation and propagation of atherosclerotic plaques, optimal management of glycemic status is required for the prevention of diabetic atherosclerosis. Continuous glucose monitoring (CGM) provides not only average glucose level but also the degree of glucose fluctuation and hypoglycemia. Given the association of glycemic variability with diabetic macrovascular diseases, CGM-based glycemic management could favorably modulate glycemic fluctuation, thereby potentially modifying atheroma burden in T2DM subjects. To test this hypothesis, the Observation of Coronary Atheroma Progression under Continuous Glucose Monitoring Guidance in Patients with Type 2 Diabetes Mellitus (OPTIMAL) study has been designed (Japan Registry of Clinical Trials: jRCT1052180152, University Hospital Medical Information Network Clinical Trial Registry UMIN000036721).

Methods

The OPTIMAL is a single-center, randomized trial to evaluate the efficacy of CGM-based glycemic control on atheroma progression in T2DM patients with CAD by using serial intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) imaging. A total of 90 eligible subjects will be randomized 1:1 into two groups to receive either CGM-based glycemic control or HbA1c-baded glycemic management. Coronary angiography and NIRS/IVUS imaging is repeated at the end of the assigned treatment period.

Results

The primary endpoint is the normalized absolute change in total atheroma volume (TAV) from baseline to 12 months. The secondary endpoints include (I) the absolute change in percent atheroma volume, (II) the percent change in lipid core burden index, (III) the change in coefficient variance measured by CGM, (IV) the change in atherogenic markers (high-density lipoprotein functionality, proprotein convertase subxilisin/kexin type 9 and fatty-acid binding proteins), and (V) the frequency of hypoglycemia. Safety will also be evaluated.

Conclusions

The collaboration of CGM use with serial NIRS/IVUS imaging will enable to compare atheroma progression rate under CGM-based glycemic management and HbA1c-based approach.

A transcriptomic model to predict increase in fibrous cap thickness in response to high-dose statin treatment: Validation by serial intracoronary OCT imaging

Background

Fibrous cap thickness (FCT), best measured by intravascular optical coherence tomography (OCT), is the most important determinant of plaque rupture in the coronary arteries. Statin treatment increases FCT and thus reduces the likelihood of acute coronary events. However, substantial statin-related FCT increase occurs in only a subset of patients. Currently, there are no methods to predict which patients will benefit. We use transcriptomic data from a clinical trial of rosuvastatin to predict if a patient's FCT will increase in response to statin therapy.

Methods

FCT was measured using OCT in 69 patients at (1) baseline and (2) after 8–10 weeks of 40  mg rosuvastatin. Peripheral blood mononuclear cells were assayed via microarray. We constructed machine learning models with baseline gene expression data to predict change in FCT. Finally, we ascertained the biological functions of the most predictive transcriptomic markers.

Findings

Machine learning models were able to predict FCT responders using baseline gene expression with high fidelity (Classification AUC = 0.969 and 0.972). The first model (elastic net) using 73 genes had an accuracy of 92.8%, sensitivity of 94.1%, and specificity of 91.4%. The second model (KTSP) using 18 genes has an accuracy of 95.7%, sensitivity of 94.3%, and specificity of 97.1%. We found 58 enriched gene ontology terms, including many involved with immune cell function and cholesterol biometabolism.

Interpretation

In this pilot study, transcriptomic models could predict if FCT increased following 8–10 weeks of rosuvastatin. These findings may have significance for therapy selection and could supplement invasive imaging modalities.

Combining cholesterol-lowering strategies with imaging data: a visible benefit?

Coronary artery disease is characterised by the development of atherosclerotic plaques and is associated with significant morbidity and mortality on a global level. However, many patients with atherosclerosis are asymptomatic and the prediction of acute coronary events is challenging. The role of imaging studies in characterising plaque morphology and stability is emerging as a valuable prognostic tool, while providing evidence for the beneficial effects of cholesterol-lowering therapy on plaque burden. This review provides an overview of contemporary studies describing the value of imaging strategies for atherosclerotic plaques. Coronary angiography is commonly used in the clinical setting, but requires a significant radiation dose (similar to computed tomography). Magnetic resonance imaging evaluation of coronary vessels would avoid exposure to ionising radiation, but is not yet feasible due to motion artefacts. The roles of alternative imaging techniques, including grey-scale intravascular ultrasound, optical coherence tomography and near-infrared spectroscopy have emerged in recent years. In particular, grey-scale intravascular ultrasound has been effectively applied to detect changes in plaque burden and features of plaques predictive of rupture, as well as plaque characteristics during cholesterol-lowering therapy, providing novel insights into factors that may contribute to treatment effectiveness. Challenges and limitations to the use of imaging techniques are considered in this context, along with future imaging strategies.

Relationship Between Preoperative Low-Density Lipoprotein Cholesterol and Periprocedural Myocardial Injury in Patients Following Elective Percutaneous Coronary Intervention in Southern China

BACKGROUND Periprocedural myocardial injury (PMI) is known to be a predictor of postprocedural cardiovascular morbidity and mortality following a percutaneous coronary intervention (PCI). However, the correlation between low-density lipoprotein cholesterol and periprocedural myocardial injury in patients following elective PCI in southern China remains unclear. Therefore, we aimed to investigate the association of preoperative low-density lipoprotein cholesterol (LDL-C) levels with PMI in patients following elective PCI. MATERIAL AND METHODS This study included 1942 consecutive patients who received elective PCI. Cardiac troponin I (cTnI) was used to assess perioperative myocardial injury. The peak cTnI was measured within 24 h after PCI, and the correlation between the cTnI value and the preoperative LDL level was studied. RESULTS The data suggest that the PCI patients with preprocedural LDL-C <100 mg/dl were strongly and independently correlated with less risk of PMI. Univariate logistic regression indicated that patients with preprocedural LDL-C of 70~99 mg/dl were correlated with lower risk of postprocedural cTnI elevation above 3×ULN (odds ratio [OR]: 0.762; 95% [CI]: 0.603-0.965; P<0.024) up to 20×ULN (OR: 0.730; 95% CI: 0.576-0.924; P<0.000) compared to those with preprocedural LDL-C ≥100 mg/dl. Moreover, patients with preprocedural LDL-C of <70 mg/dl were more strongly correlated with lower risk of postprocedural cTnI elevation above 3×ULN (OR: 0.641; 95% CI: 0.436-0.936; P<0.021) up to 20×ULN (OR: 0.476; 95% CI: 0.316-0.717; P<0.000). CONCLUSIONS Our study demonstrated that PCI patients with lower preprocedural LDL-C were correlated with a lower risk of PMI in southern China.

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

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

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

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

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

Regression of coronary atherosclerosis with infusions of the high-density lipoprotein mimetic CER-001 in patients with more extensive plaque burden

BACKGROUND

CER-001 is an engineered pre-beta high-density lipoprotein (HDL) mimetic, which rapidly mobilizes cholesterol. Infusion of CER-001 3 mg/kg exhibited a potentially favorable effect on plaque burden in the CHI-SQUARE (Can HDL Infusions Significantly Quicken Atherosclerosis Regression) study. Since baseline atheroma burden has been shown as a determinant for the efficacy of HDL infusions, the degree of baseline atheroma burden might influence the effect of CER-001.

METHODS

CHI-SQUARE compared the effect of 6 weekly infusions of CER-001 (3, 6 and 12 mg/kg) vs. placebo on coronary atherosclerosis in 369 patients with acute coronary syndrome (ACS) using serial intravascular ultrasound (IVUS). Baseline percent atheroma volume (B-PAV) cutoff associated with atheroma regression following CER-001 infusions was determined by receiver-operating characteristics curve analysis. 369 subjects were stratified according to the cutoff. The effect of CER-001 at different doses was compared to placebo in each group.

RESULTS

A B-PAV ≥30% was the optimal cutoff associated with PAV regression following CER-001 infusions. CER-001 induced PAV regression in patients with B-PAV ≥30% but not in those with B-PAV <30% (-0.45%±2.65% vs. +0.34%±1.69%, P=0.01). Compared to placebo, the greatest PAV regression was observed with CER-001 3mg/kg in patients with B-PAV ≥30% (-0.96%±0.34% vs. -0.25%±0.31%, P=0.01), whereas there were no differences between placebo (+0.09%±0.36%) versus CER-001 in patients with B-PAV <30% (3 mg/kg; +0.41%±0.32%, P=0.39; 6 mg/kg; +0.27%±0.36%, P=0.76; 12 mg/kg; +0.32%±0.37%, P=0.97).

CONCLUSIONS

Infusions of CER-001 3 mg/kg induced the greatest atheroma regression in ACS patients with higher B-PAV. These findings identify ACS patients with more extensive disease as most likely to benefit from HDL mimetic therapy.

Lipid Lowering Therapy to Modify Plaque Microstructures

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

Plaque burden, microstructures and compositions underachieving very low LDL-C levels

PURPOSE OF REVIEW

To summarize the impact of lowering LDL-C on plaque progression, microstructures and compositions.

RECENT FINDINGS

Low-density lipoprotein cholesterol (LDL-C) is a major therapeutic target to prevent atherosclerotic cardiovascular disease. Intravascular imaging has elucidated antiatherosclerotic effects of lowering LDL-C in vivo. Intensive control of LDL-C with a statin has been shown to slow plaque progression and induce its regression if very low LDL-C level is achieved. This therapeutic approach has been also demonstrated to modulate plaque microstructures and compositions. These mechanistic insights on intravascular imaging support the benefit of lowering LDL-C in achieving better cardiovascular outcomes.

SUMMARY

Lowering LDL-C level has become the first-line therapy in the primary and secondary prevention settings. The effects of lowering LDL-C on plaque progression, microstructures and compositions will be reviewed in this article.

[LDL-cholesterol and cardiovascular events: the lower the better?]

For over 30 years, intensive research efforts investigated the role of LDL cholesterol in the pathogenesis of cardiovascular disease. In various settings, large statin trials showed an association between LDL cholesterol levels and cardiovascular event rates. This association is often referred to as the 'LDL cholesterol hypothesis'. More recent trials on agents with totally different modes of action confirmed this association and indicated a causal relationship between lower LDL cholesterol levels and improved cardiovascular outcomes. It has been proposed to term this causal relationship the 'LDL cholesterol principle'. It is to be expected that currently ongoing outcomes trials will further support the assumption of a causal relationship and will finally offer an armamentarium to therapists that will enable individualized treatment of dyslipidemias and their sequelae.

Outcome after Elective Percutaneous Coronary Intervention Depends on Age in Patients with Stable Coronary Artery Disease - An Analysis of Relative Survival in a Multicenter Cohort and an OCT Substudy

Background

Age is a strong predictor of survival in patients with coronary artery disease. In elder patients with increasing co-morbidities percutaneous coronary intervention (PCI) is associated with more complications and worse outcome. The calculation of relative survival rates adjusts for the “background” mortality in the general population by correcting for age and gender. We analyzed if elder patients after elective PCI have a worse relative survival compared to younger patient groups.

Methods

A total of 8,342 patients who underwent elective PCI at two high volume centers between 1998 and 2009 were analyzed.

Results

The survival of our patients after PCI (observed survival) was slightly lower compared to the general population (expected survival) resulting in a slightly decreasing relative survival curve. In a multivariate Cox regression model age amongst others was a strong predictor of survival. Stratifying patients according to their age the relative survival curves of younger patients (Quartile 1: <58 years; 2,046 patients), elder patients (Quartile 3: 66–73 years; 2,090 patients) and very old patients (Quartile 4: >73 years; 2,307 patients) were similar. The relative survival of mid-aged patients (Quartile 2: 58–65 years; 1,899 patients) was better than that of all other patient groups. The profile of cardiovascular risk factors differs between the various groups resulting in different composition and burden of coronary plaques in an optical coherence tomography sub-study.

Conclusion

Patients after elective PCI have a slightly worse long-term survival compared to the age- and sex-matched general population. This is also true for different groups of age except for mid-aged patients between 58 and 63 years. Elder patients between 66 and 73 years and above 73 years have a similar relative survival compared to younger patients below 58 years, and might therefore have similar benefit from elective PCI.