Plaque rupture and sudden death related to exertion in men with coronary artery disease

Coronary atherosclerosis in athletes: emerging concepts and preventive strategies

There should be no assumption that an athlete is immune to coronary artery disease (CAD), even when traditional cardiovascular (CV) risk factors appear well-managed. Excelling in certain aspects of health does not equate to total CV protection. Recent data from cardiac imaging studies have raised the possibility that long-term, high-volume, high-intensity endurance exercise is associated with coronary atherosclerosis. Whilst the risk of CV events has not been shown to rise with athletic activity, the potential for CAD should not be overlooked as it is the leading cause of sudden cardiac death in athletes >35 years of age (i.e. 'Masters athletes'). Evaluating both traditional and non-traditional risk factors for CAD is the most important part of pre-participation evaluation in Masters athletes. When managing athletes at risk of CAD it is important to adopt a shared decision-making approach regarding lifestyle adaptation and lipid-lowering treatments. In the great majority of athletes, after excluding the presence of symptoms and inducible ischaemia, this advice should include encouragement to continue exercising as available data indicate that higher levels of fitness are associated with a markedly attenuated incidence of coronary events regardless of the severity of coronary disease. Future research is needed to establish the relationship between clinically relevant CAD outcomes and coronary artery calcification in Masters Athletes, the role of sex, as well as exploration of the mechanisms underpinning these unexpected CV adaptations.

Investigating the potential of catheter-assisted pulsed focused ultrasound ablation for atherosclerotic plaques

BACKGROUND

Atherosclerosis is a condition in which an adhesive substance called plaque accumulates over time inside the arteries. Plaque buildup results in the constriction of arteries, causing a shortage of blood supply to tissues and organs. Removing atherosclerotic plaques controls the development of acute ischemic stroke and heart diseases. It remains imperative for positive patient outcomes.

PURPOSE

This study sought to develop a minimally invasive technique for removing arterial plaques by applying focused ultrasound (FUS) energy on the metal surface of a nitinol catheter wire to induce inertial cavitation. The induced cavitation can deplete plaque mechanically inside the arteries, leading towards improved recanalization of blood vessels.

METHODS

The enhanced cavitation effect induced by combining FUS with a metal catheter was first verified by exposing agar phantom gels with or without a 0.9-mm diameter nitinol wire to an acoustic field produced by a 0.5-MHz FUS transducer. The phenomenon was further confirmed in pork belly fat samples with or without a 3-mm diameter nitinol catheter wire. Cavitation was monitored by detecting the peaks of emitted ultrasound signals from the samples using a passive cavitation detector (PCD). Cavitation threshold values were determined by observing the jump in the peak amplitude of signals received by the PCD when the applied FUS peak negative pressure (PNP) increased. To simulate arterial plaque removal, FUS with or without a catheter was used to remove tissues from pork belly fat samples and the lipid cores of human atherosclerotic plaque samples using 2500-cycle FUS bursts at 10% duty cycle and a burst repetition rate of 20 Hz. Treatment outcomes were quantified by subtracting the weight of samples before treatment from the weight of samples after treatment. All measurements were repeated 5 times (n = 5) unless otherwise indicated, and paired t-tests were used to compare the means of two groups. A p-value of <0.05 will be considered significant.

RESULTS

Our results showed that with a nitinol wire, the cavitation threshold in agar phantoms was reduced to 2.6 MPa from 4.3 MPa PNP when there was no nitinol wire in the focal region of FUS. For pork belly fat samples, cavitation threshold values were 1.0 and 2.0 MPa PNP, with and without a catheter wire, respectively. Pork belly fat tissues and lipid cores of atherosclerotic plaques were depleted at the interface between a catheter and the samples at 2 and 4 MPa FUS PNP, respectively. The results showed that with a catheter wire in the focal region of a 3-min FUS treatment session, 24.7 and 25.6 mg of lipid tissues were removed from pork belly fat and human atherosclerotic samples, respectively. In contrast, the FUS-only group showed no reduction in sample weight. The differences between FUS-only and FUS-plus-catheter groups were statistically significant (p < 0.001 for the treatment on pork belly samples, and p < 0.01 for the treatment on human atherosclerotic samples).

CONCLUSION

This study demonstrated the feasibility of catheter-assisted FUS therapy for removing atherosclerotic plaques.

Molecular Insight into Acute Limb Ischemia

Acute limb ischemia (ALI) is defined as a sudden reduction in blood flow to a limb, resulting in cessation of blood flow and, therefore, cessation of the delivery of nutrients and oxygen to the tissues of the lower limb. Despite optimal treatment to restore blood flow to ischemic tissues, some patients may suffer from ischemia/reperfusion (I/R) syndrome, the most severe complication after a revascularization procedure used to restore blood flow. There are multiple molecular and cellular factors that are involved in each phase of ALI. This review focuses firstly on molecular and cellular factors of arterial thrombosis, highlighting the role of atherosclerotic plaques, smooth muscle cells (SMCs), and cytokine which may alter key components of the extracellular matrix (ECM). Then, molecular and cellular factors of arterial embolism will be discussed, highlighting the importance of thrombi composition. Molecular and cellular factors of ischemia/reperfusion syndrome are analyzed in depth, highlighting several important mechanisms related to tissue damage, such as inflammation, apoptosis, autophagy, necrosis, and necroptosis. Furthermore, local and general complications of ALI are discussed in the context of molecular alterations. Ultimately, the role of novel biomarkers and targeted therapies is discussed.

Simulation of stress in a blood vessel due to plaque sediments in coronary artery disease

Atherosclerosis is a cardiovascular disease mainly caused by plaque deposition in blood vessels. Plaque comprises components such as thrombosis, fibrin, collagen, and lipid core. It plays an essential role in inducing rupture in a blood vessel. Generally, Plaque could be described as three kinds of elastic models: cellular Plaque, hypocellular Plaque, and calcified Plaque. The present study aimed to investigate the behavior of atherosclerotic plaque rupture according to different lipid cores using Fluid-Structure Interaction (FSI). The blood vessel was also varied with different thicknesses (0.05, 0.25, and 0.5 mm). In this study, FSI simulation with a cellular plaque model with various thicknesses was investigated to obtain information on plaque rupture. Results revealed that the blood vessel with Plaque having a lipid core represents higher stresses than those without a lipid core. Blood vessels' thin thickness, like a thin cap, results in more considerable than Von Mises stress. The result also suggests that even at low fracture stress, the risk of rupture due to platelet decomposition at the gap was more significant for cellular plaques.

Possible Mechanisms for Adverse Cardiac Events Caused by Exercise-Induced Hypertension in Long-Distance Middle-Aged Runners: A Review

Sudden cardiac death (SCD) is rare among athletes. However, hypertrophic cardiomyopathy is the leading cause of SCD among those <35 years of age. Meanwhile, coronary artery disease (CAD) is the primary SCD cause among those ≥35 years of age. CAD-induced plaque ruptures are believed to be a significant cause of cardiovascular diseases in middle-aged individuals who participate in extreme long-distance running activities such as marathons. A total of 1970 articles related to EIH were identified using search terms. Out of these, 1946 studies were excluded for reasons such as arterial hypertension, exercise-induced pulmonary hypertension, the absence of exercise stress testing (EST), and a lack of relevance to EIH. The study analyzed 24 studies related to both long-distance runners with exercise-induced hypertension (EIH) and the general public. Among these, 11 studies were quasi-experimentally designed studies used in randomized controlled trials (RCTs) on long-distance runners with EIH. Additionally, 12 studies utilized cohort designs, and one study with a quasi-experimental design was conducted among the general population. Recent studies suggest that an imbalance between oxygen demand and supply due to ventricular hypertrophy may be the actual cause of cardiovascular disease, regardless of CAD. Exercising excessively over an extended period can reduce endothelial function and increase arterial stiffness, which in turn increases afterload and leads to an excessive increase in blood pressure during exercise. Exercise-induced hypertension (EIH), which increases the morbidity rate of resting hypertension and is a risk factor for cardio-cerebro-vascular diseases, is more prevalent in middle-aged long-distance runners than in runners from other age groups, and it increases the prevalence of critical arrhythmias, such as atrial fibrillation or ventricular arrhythmias. EIH is associated with angiotensin II activity, and angiotensin II receptor blockers show promising effects in middle-aged runners. Further, guidelines for preventing excessive participation in races and restricting exercise intensity and frequency would be useful. This review identifies EIH as a potential risk factor for cardiovascular diseases and describes how EIH induces SCD.

The interplay of collagen, macrophages, and microcalcification in atherosclerotic plaque cap rupture mechanics

The rupture of an atherosclerotic plaque cap overlying a lipid pool and/or necrotic core can lead to thrombotic cardiovascular events. In essence, the rupture of the plaque cap is a mechanical event, which occurs when the local stress exceeds the local tissue strength. However, due to inter- and intra-cap heterogeneity, the resulting ultimate cap strength varies, causing proper assessment of the plaque at risk of rupture to be lacking. Important players involved in tissue strength include the load-bearing collagenous matrix, macrophages, as major promoters of extracellular matrix degradation, and microcalcifications, deposits that can exacerbate local stress, increasing tissue propensity for rupture. This review summarizes the role of these components individually in tissue mechanics, along with the interplay between them. We argue that to be able to improve risk assessment, a better understanding of the effect of these individual components, as well as their reciprocal relationships on cap mechanics, is required. Finally, we discuss potential future steps, including a holistic multidisciplinary approach, multifactorial 3D in vitro model systems, and advancements in imaging techniques. The obtained knowledge will ultimately serve as input to help diagnose, prevent, and treat atherosclerotic cap rupture.

Effect of regular exercise training on platelet function in patients with cardiovascular disease and healthy individuals: A systematic review

INTRODUCTION

Regular exercise training is essential in prevention and treatment of cardiovascular disease (CVD), yet the beneficial effects of exercise remain only partly explained. Platelets play a key role in CVD and may be affected by regular exercise training. We aimed to systematically summarise studies investigating the effect of regular exercise training on platelet function in patients with CVD and in healthy individuals.

METHODS

Studies were identified by PubMed, Embase and Web of Science May 16, 2022. We selected studies investigating markers of platelet function in relation to regular exercise training in patients with CVD and in healthy individuals. Regular exercise was defined as exercise training for four weeks or more.

RESULTS

Of the included studies, 11 investigated patients with CVD and 29 were on healthy individuals. Studies were heterogeneous regarding design, study population and methodology, and the results were ambiguous. In total, 52 different markers of platelet function were investigated with platelet aggregation, soluble P-selectin, and thromboxane B2 (TXB2) as the most frequently examined. When evaluating between-group changes after regular exercise, two studies found a reduced platelet aggregation in the exercise group whilst three studies did not find a difference between groups. With respect to TXB2, three studies reported a reduction and two studies an increase in the exercise group. There were no between-group differences in the seven studies examining soluble P-selectin.

CONCLUSION

Regular exercise training has no clear impact on platelet function in patients with CVD or healthy individuals.

PROSPERO REGISTRATION

CRD42022350539.

The Lancet Commission to reduce the global burden of sudden cardiac death: a call for multidisciplinary action

Despite major advancements in cardiovascular medicine, sudden cardiac death (SCD) continues to be an enormous medical and societal challenge, claiming millions of lives every year. Efforts to prevent SCD are hampered by imperfect risk prediction and inadequate solutions to specifically address arrhythmogenesis. Although resuscitation strategies have witnessed substantial evolution, there is a need to strengthen the organisation of community interventions and emergency medical systems across varied locations and health-care structures. With all the technological and medical advances of the 21st century, the fact that survival from sudden cardiac arrest (SCA) remains lower than 10% in most parts of the world is unacceptable. Recognising this urgent need, the Lancet Commission on SCD was constituted, bringing together 30 international experts in varied disciplines. Consistent progress in tackling SCD will require a completely revamped approach to SCD prevention, with wide-sweeping policy changes that will empower the development of both governmental and community-based programmes to maximise survival from SCA, and to comprehensively attend to survivors and decedents' families after the event. International collaborative efforts that maximally leverage and connect the expertise of various research organisations will need to be prioritised to properly address identified gaps. The Commission places substantial emphasis on the need to develop a multidisciplinary strategy that encompasses all aspects of SCD prevention and treatment. The Commission provides a critical assessment of the current scientific efforts in the field, and puts forth key recommendations to challenge, activate, and intensify efforts by both the scientific and global community with new directions, research, and innovation to reduce the burden of SCD worldwide.

Sudden cardiac death in ischaemic heart disease: coronary thrombosis or myocardial fibrosis?

The mechanisms underlying sudden cardiac death (SCD) in patients with ischaemic heart disease (IHD) caused by coronary atherosclerosis are not yet clarified. For decades, acute coronary causes have been sought as the main triggers of SCD in these patients. In fact, angiographic and pathological studies in cardiac arrest survivors and SCD victims, respectively, consistently show that acute plaque events occur in ∼50% of SCD of patients with IHD. Among the acute events, plaque rupture and erosion triggering acute coronary thrombosis remain the main substrates; however, a significant percentage of plaque haemorrhage (20%) is identified by pathological studies. Its role in acute coronary thrombosis is unknown and deserves future intravascular imaging developments. In the remaining 50% of SCD, the atherosclerotic coronary disease shows the characteristics of structural stability. More recent studies have focused attention not only on the coronary tree and on the search for acute complications of atherosclerotic plaques but also on myocardial tissue, identifying replacement and patchy fibrosis as the most frequent findings in the post-mortem hearts of these patients, a feature followed by cardiac hypertrophy, as assessed by the heart weight, usually associated with fibrosis. The possibility of characterizing myocardial fibrosis in vivo, besides confirming the pathological data, now offers new risk stratification perspectives to prevent SCD in IHD, alongside the consolidated secondary prevention criteria based on left ventricular dysfunction.

Incidence of Cardiac Arrest During Sports Among Women in the European Union

BACKGROUND

Women represent a growing proportion of sports participants. Still, few original data regarding sudden cardiac arrest during sports (Sr-SCA) in women are available.

OBJECTIVES

The authors sought to assess the incidence, characteristics, and outcomes of women presenting with Sr-SCA.

METHODS

Data were analyzed from 3 population-based European registries (ESCAPE-NET 2020 Horizon Program) that prospectively and exhaustively collect every case of SCA: SDEC (Paris-Sudden Death Expertise Center), ARREST (AmsteRdam REsuscitation Studies), and SRCR (Swedish Register for Cardiopulmonary Resuscitation). Sr-SCA was defined as SCA during or ≤1 hour after cessation of sports activity.

RESULTS

Of 34,826 SCA between 2006 and 2017, 760 Sr-SCA (2.2%) were identified, including 54 in women. The average annual incidence of Sr-SCA in women in the 3 registries ranged from 0.10 per million (95% CI: 0.01-0.71 per million) to 0.38 per million (95% CI: 0.14-1.04 per million). Overall, the average annual incidence rate of Sr-SCA in women was 0.19 per million (95% CI: 0.14-0.24 per million), >10-fold lower compared with men (2.63 per million [95% CI: 2.45-2.83 per million]; P < 0.0001). When extrapolating to the total European population and accounting for age and sex, this yields 98 cases per year (95% CI: 72-123 cases per year) in women and 1,350 cases per year (95% CI: 1,256-1,451 cases per year) in men. Subject characteristics and circumstances of occurrence were similar in women vs men. Bystander response, time to defibrillation, and survival rate at hospital admission (58.8% vs 58.5%; P = 0.99) and 30 days did not differ significantly between women and men.

CONCLUSIONS

These findings emphasize the dramatically lower risk of Sr-SCA in women compared with men, despite similar subject characteristics. This should be considered in designing preparticipation screening strategies in the future.

Association of the time of day of peak physical activity with cardiovascular mortality: Findings from the UK Biobank study

Cardiovascular physiology and pathophysiology display pronounced circadian rhythms. The study is designed to examine whether the time of day of physical activity is associated with cardiovascular mortality. We analyzed 94,489 UK Biobank adults with objectively measured physical activity, including 53,328 morning-type participants and 30,962 evening-type participants based on self-reported chronotypes. The time of day of peak physical activity was categorized using a machine learning algorithm: early morning (n = 18,477), late morning (n = 25,700), midday (reference) (n = 27,803), and night (n = 22,509). Hazard ratios of cardiovascular mortality were examined using the Cox proportional hazards model. During a median follow-up of 6.9 years (interquartile range, 6.3-7.4 years), we identified 629 cardiovascular deaths. The hazard of cardiovascular mortality was elevated in the early morning group (hazard ratio = 1.56, 95% Confidence Interval [1.23-1.98]) and night group (1.49, [1.18-1.88]) but not in the late morning group (1.21, [0.98-1.47]) compared to the referent midday group. In the chronotype-stratified analysis, the increased cardiovascular mortality in the morning group was only observed in the evening-type participants, while the increased cardiovascular mortality in the night group was only observed in the morning-type participants. In conclusion, optimizing the timing of peak physical activity according to cardiovascular circadian rhythms and individual chronotypes could be a potential therapeutic target that brings additional health benefits.

Potential relationship between high wall shear stress and plaque rupture causing acute coronary syndrome

The relationship between high wall shear stress (WSS) and plaque rupture (PR) in longitudinal and circumferential locations remains uncertain. Overall, 100 acute coronary syndrome patients whose culprit lesions had PR, documented by optical coherence tomography (OCT), were enrolled. Lesion-specific three-dimensional coronary artery models were created using OCT data. WSS was computed with computational fluid dynamics analysis. PR was classified into upstream-PR, minimum lumen area-PR, and downstream-PR according to the PR's longitudinal location, and into central-PR and lateral-PR according to the disrupted fibrous cap circumferential location. In the longitudinal 3-mm segmental analysis, multivariate analysis demonstrated that higher WSS in the upstream segment was independently associated with upstream-PR, and thinner fibrous cap was independently associated with downstream-PR. In the PR cross-sections, the PR region had a significantly higher average WSS than non-PR region. In the cross-sectional analysis, the in-lesion peak WSS was frequently observed in the lateral (66.7%) and central regions (70%) in lateral-PR and central-PR, respectively. Multivariate analysis demonstrated that the presence of in-lesion peak WSS at the lateral region, thinner broken fibrous cap, and larger lumen area were independently associated with lateral-PR, while the presence of in-lesion peak WSS at the central region and thicker broken fibrous cap were independently associated with central-PR. In conclusion, OCT-based WSS simulation revealed that high WSS might be related to the longitudinal and circumferential locations of PR.

Sports-related sudden cardiac arrest in young adults

AIMS

Data on sports-related sudden cardiac arrest (SrSCA) among young adults in the general population are scarce. We aimed to determine the overall SrSCA incidence, characteristics, and outcomes in young adults.

METHODS AND RESULTS

Prospective cohort study of all cases of SrSCA between 2012 and 2019 in Germany and Paris area, France, involving subjects aged 18-35 years. Detection of SrSCA was achieved via multiple sources, including emergency medical services (EMS) reporting and web-based screening of media releases. Cases and aetiologies were centrally adjudicated. Overall, a total of 147 SrSCA (mean age 28.1 ± 4.8 years, 95.2% males) occurred, with an overall burden of 4.77 [95% confidence interval (CI) 2.85-6.68] cases per million-year, including 12 (8.2%) cases in young competitive athletes. While bystander cardiopulmonary resuscitation (CPR) was initiated in 114 (82.6%), automated external defibrillator (AED) use by bystanders occurred only in a minority (7.5%). Public AED use prior to EMS arrival (odds ratio 6.25, 95% CI 1.48-43.20, P = 0.02) was the strongest independent predictor of survival at hospital discharge (38.1%). Among cases that benefited from both immediate bystander CPR and AED use, survival rate was 90.9%. Coronary artery disease was the most frequent aetiology (25.8%), mainly through acute coronary syndrome (86.9%).

CONCLUSION

Sports-related sudden cardiac arrest in the young occurs mainly in recreational male sports participants. Public AED use remains disappointingly low, although survival may reach 90% among those who benefit from both bystander CPR and early defibrillation. Coronary artery disease is the most prevalent cause of SrSCA in young adults.

The Role of Fine Particles (PM 2.5) in the Genesis of Atherosclerosis and Myocardial Damage: Emphasis on Clinical and Epidemiological Data, and Pathophysiological Mechanisms

Due to the fact that atherosclerotic cardiovascular diseases (CVDs) dominate in the structure of morbidity, disability and mortality of the population, the study of the risk factors for the development of atherosclerotic CVDs, as well as the study of the underlying pathogenetic mechanisms thereof, is the most important area of scientific research in modern medicine. Understanding these aspects will allow to improve the set of treatment and preventive measures and activities. One of the important risk factors for the development of atherosclerosis, which has been actively studied recently, is air pollution with fine particulate matter (PM 2.5). According to clinical and epidemiological data, the level of air pollution with PM 2.5 exceeds the normative indicators in most regions of the world and is associated with subclinical markers of atherosclerosis and mortality from atherosclerotic CVDs. The aim of this article is to systematize and discuss in detail the role of PM 2.5 in the development of atherosclerosis and myocardial damage.

Plaque histology and myocardial disease in sudden coronary death: the Fingesture study

AIMS

At least 50% of deaths due to coronary artery disease (CAD) are sudden cardiac deaths (SCDs), but the role of acute plaque complications on the incidence of sudden death in CAD is somewhat unclear. The present study aimed to investigate plaque histology and concomitant myocardial disease in sudden coronary death.

METHODS AND RESULTS

The study population is derived from the Fingesture study, which has collected data from 5869 consecutive autopsy-verified SCD victims in Northern Finland (population ≈600 000) between 1998 and 2017. In this substudy, histological examination of culprit lesions was performed in 600 SCD victims whose death was due to CAD. Determination of the cause of death was based on the combination of medical records, police reports, and autopsy data. Plaque histology was classified as either (i) plaque rupture or erosion, (ii) intraplaque haemorrhage, or (iii) stable plaque. The mean age of the study subjects was 64.9 ± 11.2 years, and 82% were male. Twenty-four per cent had plaque rupture or plaque erosion, 24% had an intraplaque haemorrhage, and 52% had a stable plaque. Myocardial hypertrophy was present in 78% and myocardial fibrosis in 93% of victims. The presence of myocardial hypertrophy or fibrosis was not associated with specific plaque histology.

CONCLUSION

Less than half of sudden deaths due to CAD had evidence of acute plaque complication, an observation which is contrary to historical perceptions. The prevalence of concomitant myocardial disease was high and independent of associated plaque morphology.

Coronary Artery Disease, Cardiac Arrest, and Shared Decision Making in a Recreational Athlete

A highly active 59-year-old-man with a history of cardiac arrest and myocardial infarction presented for exercise recommendations. Multimodality risk stratification led to ventricular fibrillation cardiac arrest at the completion of a maximal effort cardiopulmonary exercise test. Using shared decision making, the safety and feasibility of returning to exercise were discussed. (Level of Difficulty: Intermediate.).

Early versus late acute coronary syndrome risk patterns of coronary atherosclerotic plaque

AIMS

The temporal instability of coronary atherosclerotic plaque preceding an incident acute coronary syndrome (ACS) is not well defined. We sought to examine differences in the volume and composition of coronary atherosclerosis between patients experiencing an early (≤90 days) versus late ACS (>90 days) after baseline coronary computed tomography angiography (CCTA).

METHODS AND RESULTS

From a multicenter study, we enrolled patients who underwent a clinically indicated baseline CCTA and experienced ACS during follow-up. Separate core laboratories performed blinded adjudication of ACS events and quantification of CCTA including compositional plaque volumes by Hounsfield units (HU): calcified plaque >350 HU, fibrous plaque 131-350 HU, fibrofatty plaque 31-130 HU and necrotic core <30 HU. In 234 patients (mean age 62 ± 12 years, 36% women), early and late ACS occurred in 129 and 105 patients after a mean of 395 ± 622 days, respectively. Patients with early ACS had a greater maximal diameter stenosis and maximal cross-sectional plaque burden as compared to patients with late ACS (P < 0.05). Larger total, fibrous, fibrofatty, and necrotic core volumes were observed in the early ACS group (P < 0.05). Findings for total, fibrous, fibrofatty, and necrotic core volumes were reproduced in an external validation cohort (P < 0.05).

CONCLUSIONS

Volumetric differences in composition of coronary atherosclerosis exist between ACS patients according to their timing antecedent to the acute event. These data support that a large burden of non-calcified plaque on CCTA is strongly associated with near-term plaque instability and ACS risk.

Lack of Early Etiologic Investigations in Young Sudden Cardiac Death

BACKGROUND

Since majority of sudden cardiac arrest (SCA) victims die in the intensive care unit (ICU), early etiologic investigations may improve understanding of SCA and targeted prevention.

METHODS

In this prospective, population-based registry all SCA admitted alive across the 48 hospitals of the Paris area were enrolled. We investigated the extent of early etiologic work-up among young SCD cases (<45 years) eventually dying within the ICU.

RESULTS

From May 2011 to May 2018, 4,314 SCA patients were admitted alive. Among them, 3,044 died in ICU, including 484 (15.9%) young patients. SCA etiology was established in 233 (48.1%) and remained unexplained in 251 (51.9%). Among unexplained (compared to explained) cases, coronary angiography (17.9 vs. 49.4%, P<0.001), computed tomography scan (24.7 vs. 46.8%, P<0.001) and trans-thoracic echocardiography (31.1 vs. 56.7%, P<0.001) were less frequently performed. Only 22 (8.8%) patients with unexplained SCD underwent all three investigations. SCDs with unexplained status decreased significantly over the 7 years of the study period (from 62.9 to 35.2%, P=0.005). While specialized TTE and CT scan performances have increased significantly, performance of early coronary angiography did not change. Autopsy, genetic analysis and family screening were performed in only 48 (9.9%), 5 (1.0%) and 14 cases (2.9%) respectively.

CONCLUSIONS

More than half of young SCD dying in ICU remained etiologically unexplained; this was associated with a lack of early investigations. Improving early diagnosis may enhance both SCA understanding and prevention, including for relatives. Failure to identify familial conditions may result in other preventable deaths within these families.

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.

Investigating the effects of external pressure on coronary arteries with plaques and its role in coronary artery disease

The risk of an acute coronary event stems from the amount and type of plaque present, as well as the fluid and structural dynamics in the coronary artery. If the plaque's structural stress exceeds the mechanical strength, the fibrous cap may rupture and lead to thrombosis. The patient is then likely to face a sudden myocardial infarction. An association between Coronary Heart Disease (CHD) and Sudden Cardiac Death (SCD) has been long recognised. For the first time, we are reporting a correlation between applied external pressure, such as Cardiopulmonary Resuscitation (CPR), coughing, sneezing, blowing one's nose, etc., and diseased coronary artery plaque via 3 D coronary artery models and two-way Fluid-Solid Interaction (FSI) models. Shear and von Mises stresses inside arteries and plaques have been shown to play a major role in plaque development, progression of disease, and the likelihood of plaque rupture. Our results show a drastic change in maximum shear (300%) and von Mises stresses (500%) with increasing external pressure. This change may indicate an onset of imminent plaque rupture. Furthermore, FSI modelling indicates a strong correlation between plaque thickness, location, and external pressure. With further clinical and simulation studies, this information could be helpful in understanding potential limit pressure in the CPR process for patients with CHD.

Tissue-engineered collagenous fibrous cap models to systematically elucidate atherosclerotic plaque rupture

A significant amount of vascular thrombotic events are associated with rupture of the fibrous cap that overlie atherosclerotic plaques. Cap rupture is however difficult to predict due to the heterogenous composition of the plaque, unknown material properties, and the stochastic nature of the event. Here, we aim to create tissue engineered human fibrous cap models with a variable but controllable collagen composition, suitable for mechanical testing, to scrutinize the reciprocal relationships between composition and mechanical properties. Myofibroblasts were cultured in 1 × 1.5 cm-sized fibrin-based constrained gels for 21 days according to established (dynamic) culture protocols (i.e. static, intermittent or continuous loading) to vary collagen composition (e.g. amount, type and organization). At day 7, a soft 2 mm ∅ fibrin inclusion was introduced in the centre of each tissue to mimic the soft lipid core, simulating the heterogeneity of a plaque. Results demonstrate reproducible collagenous tissues, that mimic the bulk mechanical properties of human caps and vary in collagen composition due to the presence of a successfully integrated soft inclusion and the culture protocol applied. The models can be deployed to assess tissue mechanics, evolution and failure of fibrous caps or complex heterogeneous tissues in general.

Optical Coherence Tomographic Features of Pancoronary Plaques in Patients With Acute Myocardial Infarction Caused by Layered Plaque Rupture Versus Layered Plaque Erosion

Atherosclerotic plaque instability could occur on the basis of healed plaque which has a layered appearance on optical coherence tomography. This study aimed to investigate pancoronary plaque features of layered plaque rupture (LPR) and layered plaque erosion (LPE) in patients with acute myocardial infarction. Among 388 patients with acute myocardial infarction who underwent preintervention optical coherence tomography imaging of three coronary arteries, 190 patients with layered culprit plaque (49.0%) were identified and further divided into 2 groups: LPR group and LPE group. Clinical characteristics, pancoronary plaque features and clinical outcomes were compared between the 2 groups. Patients with LPR were older, less often male and current smoker, and had a lower coronary flow grade than those with LPE. At the culprit lesion, LPR group had a higher prevalence of lipid plaque, thin-cap fibroatheroma (TCFA), macrophage, and microchannel, and presented with more severe lumen area stenosis than LPE group. At nonculprit lesions, LPR group had a higher prevalence of TCFA and had greater layered tissue thickness and area than LPE group. The ischemia-driven revascularization rate was higher in LPR group. Moreover, we found that TCFA, diameter stenosis >56.5%, and mean lipid arc >179.1° were predictors for layered culprit plaque. In conclusion, patients with LPR had more vulnerable plaque features at culprit and nonculprit lesions and had higher incidence of ischemia-driven revascularization than those with LPE. TCFA, diameter stenosis >56.5%, and mean lipid arc >179.1° were predictors of layered culprit plaque.

Influence of cardiopulmonary exercise test on platelet function in patients with coronary artery diseases on antiplatelet therapy

Background

Cardiac rehabilitation reduces mortality and morbidity rate of patients with coronary artery diseases (CAD); however, acute exercise stimulation may also increase the thrombotic risk through platelet activation. Studies on the effects of cardiac rehabilitation on platelet function have been sparse.

Methods

A total of 28 patients (24 men and 4 women; average age = 54.6 ± 8 years old) with stable CAD were enrolled in this study and divided into Aspirin-treated (n = 11; Aspirin group) and dual-antiplatelet-treated group (DAPT group; n = 17). Symptom-limited cardiopulmonary exercise test (CPET) with a cycle ergometer was performed on all the patients. Before and after CPET, platelet function was evaluated using light transmission aggregometry and whole blood flow cytometry.

Results

All patients completed the CPET without provoked cardiac events, and the mean value of peak oxygen uptake (Peak Vo₂) was 19.3 ± 3 ml/(kg min). Prior to CPET, platelet aggregation was significantly suppressed in DAPT group compared to Aspirin group (43.0 ± 21.5 vs. 72.9 ± 7.5, p < 0.001). CPET promoted platelet aggregation in Aspirin group (72.9 ± 7.5 vs. 80.9 ± 7.6, p = 0.005) and DAPT group (43.0 ± 21.5 vs. 50.1 ± 20.9, p = 0.010), and platelet count was increased in Aspirin (210.9 ± 54.6 vs. 227.5 ± 58.1, p = 0.001) and DAPT group (217.5 ± 63.8 vs. 229.7 ± 63.7, p = 0.001). However, the expression levels of CD62p and PAC-1 were not affected by CPET in both groups.

Conclusion

Symptom-limited CPET enhanced platelet aggregation in patients with CAD despite treatment with antiplatelet, mainly via platelet count augmentation, but not through single platelet activation.

Trial registration: Effects of high intensity interval training versus moderate intensity continue training in cardiac rehabilitation on platelet function of patients with coronary heart diseases: a exploratory randomized controlled trial.

ChiCTR-INR-17010717. Registered 23 February 2017, https://www.chictr.org.cn/edit.aspx?pid=18206&htm=4.

The Correlation Between Wall Shear Stress and Plaque Composition in Advanced Human Carotid Atherosclerosis

The role of wall shear stress (WSS) in atherosclerotic plaque development is evident, but the relation between WSS and plaque composition in advanced atherosclerosis, potentially resulting in plaque destabilization, is a topic of discussion. Using our previously developed image registration pipeline, we investigated the relation between two WSS metrics, time-averaged WSS (TAWSS) and the oscillatory shear index (OSI), and the local histologically determined plaque composition in a set of advanced human carotid plaques. Our dataset of 11 carotid endarterectomy samples yielded 87 histological cross-sections, which yielded 511 radial bins for analysis. Both TAWSS and OSI values were subdivided into patient-specific low, mid, and high tertiles. This cross-sectional study shows that necrotic core (NC) size and macrophage area are significantly larger in areas exposed to high TAWSS or low OSI. Local TAWSS and OSI tertile values were generally inversely related, as described in the literature, but other combinations were also found. Investigating the relation between plaque vulnerability features and different combinations of TAWSS and OSI tertile values revealed a significantly larger cap thickness in areas exposed to both low TAWSS and low OSI. In conclusion, our study confirmed previous findings, correlating high TAWSS to larger macrophage areas and necrotic core sizes. In addition, our study demonstrated new relations, correlating low OSI to larger macrophage areas, and a combination of low TAWSS and low OSI to larger cap thickness.

Vulnerable Plaque in Patients with Acute Coronary Syndrome: Identification, Importance, and Management

MI is a leading cause of morbidity and mortality worldwide. Coronary artery thrombosis is the final pathologic feature of the most cases of acute MI primarily caused by atherosclerotic coronary artery disease. The concept of vulnerable plaque has evolved over the years but originated from early pioneering work unveiling the crucial role of plaque rupture and subsequent coronary thrombosis as the dominant cause of MI. Along with systemic cardiovascular risk factors, developments of intravascular and non-invasive imaging modalities have allowed us to identify coronary plaques thought to be at high risk for rupture. However, morphological features alone may only be one of many factors which promote plaque progression. The current vulnerable-plaque-oriented approaches to accomplish personalized risk assessment and treatment have significant room for improvement. In this review, the authors discuss recent advances in the understanding of vulnerable plaque and its management strategy from pathology and clinical perspectives.

Optimization Study of the Hemodynamics of Saline Flushing in Endoscopic Imaging of Chronic Total Occlusions (CTOs)

PURPOSE

In this study, in vitro experiments and computational fluid dynamic (CFD) simulations are used to expand the understand of the physics of saline flushing of a blocked artery to enable optical imaging. This process involves saline injection, mixing with blood, and advection of the mixture away from the region of interest to provide a clear optical path for imaging.

METHODS

CFD simulations are used as a rapid turn-around tool for the evolutionary design process of an endovascular catheter that combines imaging forward-viewing element with saline flushing lumens.

RESULTS

A novel design and control technique is developed that provides the method to regulate the pressure in a blocked artery during saline flushing, so only small deviations from physiological pressure values are exerted on the damaged artery wall at any time, minimizing risk of rupture. In vitro experiments demonstrate the optical clearing process in phantoms simulating chronic total occlusions (CTOs) in coronary arteries with an opaque blood surrogate being removed by saline flushing. With the CFD compared by the experiments, parametric analyses of artery diameter and curvature, and flushing lumen diameter size were conducted to understand their impact on flushing times and pressures. Different plaque morphologies were studied to explore the feasibility of saline flushing in different CTO conditions.

CONCLUSIONS

A new catheter design is demonstrated to safely and effectively produce saline flushing, leading to a clear optical imaging field, and an improved technique is outlined that overcomes some practical challenges and limitations commonly encountered in angioscopy.

Thin-cap fibroatheroma predicts clinical events in diabetic patients with normal fractional flow reserve: the COMBINE OCT-FFR trial

AIMS

The aim of this study was to understand the impact of optical coherence tomography (OCT)-detected thin-cap fibroatheroma (TCFA) on clinical outcomes of diabetes mellitus (DM) patients with fractional flow reserve (FFR)-negative lesions.

METHODS AND RESULTS

COMBINE OCT-FFR study was a prospective, double-blind, international, natural history study. After FFR assessment, and revascularization of FFR-positive lesions, patients with ≥1 FFR-negative lesions (target lesions) were classified in two groups based on the presence or absence of ≥1 TCFA lesion. The primary endpoint compared FFR-negative TCFA-positive patients with FFR-negative TCFA-negative patients for a composite of cardiac mortality, target vessel myocardial infarction, clinically driven target lesion revascularization or unstable angina requiring hospitalization at 18 months. Among 550 patients enrolled, 390 (81%) patients had ≥1 FFR-negative lesions. Among FFR-negative patients, 98 (25%) were TCFA positive and 292 (75%) were TCFA negative. The incidence of the primary endpoint was 13.3% and 3.1% in TCFA-positive vs. TCFA-negative groups, respectively (hazard ratio 4.65; 95% confidence interval, 1.99-10.89; P < 0.001). The Cox regression multivariable analysis identified TCFA as the strongest predictor of major adverse clinical events (MACE) (hazard ratio 5.12; 95% confidence interval 2.12-12.34; P < 0.001).

CONCLUSIONS

Among DM patients with ≥1 FFR-negative lesions, TCFA-positive patients represented 25% of this population and were associated with a five-fold higher rate of MACE despite the absence of ischaemia. This discrepancy between the impact of vulnerable plaque and ischaemia on future adverse events may represent a paradigm shift for coronary artery disease risk stratification in DM patients.

Nonlinear multiscale analysis of coronary atherosclerotic vulnerable plaque artery: fluid-structural modeling with micromechanics

A unique three-dimensional (3D) computational multiscale modeling approach is proposed to investigate the influence of presence of microcalcification particles on the stress field distribution in the thin cap layer of a coronary atherosclerotic vulnerable plaque system. A nested 3D modeling analysis framework spanning the multiscale nature of a coronary atherosclerotic vulnerable plaque is presented. At the microscale level, a micromechanical modeling approach, which is based on computational finite-element (FE) representative unit cell, is applied to obtain the homogenized nonlinear response of the calcified tissue. This equivalent response effectively allows the integration of extremely small microcalcification inclusions in a global biomechanical FE model. Next, at the macroscale level, a 3D patient-based fluid-structure interaction FE model, reconstructing a refined coronary artery geometry with calcified plaque lesion, is generated to study the mechanical behavior of such multi-component biomechanical system. It is shown that the proposed multiscale modeling approach can generate a higher resolution of stress and strain field distributions within the coronary atherosclerotic vulnerable plaque system and allow the assessment of the local concentration stress around the microcalcifications in plaque cap layers. A comparison of stress field distributions within cap layers with and without inclusion of microcalcifications is also presented.

Cardiac Biomarkers and Autoantibodies in Endurance Athletes: Potential Similarities with Arrhythmogenic Cardiomyopathy Pathogenic Mechanisms

The “Extreme Exercise Hypothesis” states that when individuals perform training beyond the ideal exercise dose, a decline in the beneficial effects of physical activity occurs. This is due to significant changes in myocardial structure and function, such as hemodynamic alterations, cardiac chamber enlargement and hypertrophy, myocardial inflammation, oxidative stress, fibrosis, and conduction changes. In addition, an increased amount of circulating biomarkers of exercise-induced damage has been reported. Although these changes are often reversible, long-lasting cardiac damage may develop after years of intense physical exercise. Since several features of the athlete’s heart overlap with arrhythmogenic cardiomyopathy (ACM), the syndrome of “exercise-induced ACM” has been postulated. Thus, the distinction between ACM and the athlete’s heart may be challenging. Recently, an autoimmune mechanism has been discovered in ACM patients linked to their characteristic junctional impairment. Since cardiac junctions are similarly impaired by intense physical activity due to the strong myocardial stretching, we propose in the present work the novel hypothesis of an autoimmune response in endurance athletes. This investigation may deepen the knowledge about the pathological remodeling and relative activated mechanisms induced by intense endurance exercise, potentially improving the early recognition of whom is actually at risk.

Cardiac-CT with the newest CT scanners: An incoming screening tool for competitive athletes?

Competitive athletes of all skill levels are at risk of sudden cardiac death (SCD) due to certain heart conditions. Prior to engagement in high-intensity athletics, it is necessary to screen for these conditions in order to prevent sudden cardiac death. Cardiac-CT angiography (CCTA) is a reliable tool to rule out the leading causes of SCD by providing an exceptional overview of vascular and cardiac morphology. This allows CCTA to be a powerful resource in identifying cardiac anomalies in selected patients (i.e. unclear symptoms or findings at ECG or echocardiography) as well as to exclude significant coronary artery disease (CAD). With the advancement of technology over the last few years, the latest generations of computed tomography (CT) scanners provide better image quality at lower radiation exposures. With the amount of radiation exposure per scan now reaching the sub-millisievert range, the number of CT examinations it is supposed to increase greatly, also in the athlete's population. It is thus necessary for radiologists to have a clear understanding of how to make and interpret a CCTA examination so that these studies may be performed in a responsible and radiation conscious manner especially when used in the younger populations. Our work aims to illustrate the main radiological findings of CCTAs and highlight their clinical impact with some case studies. We also briefly describe critical features of state-of-the-art CT scanners that optimize different acquisitions to obtain the best quality at the lowest possible dose.

The role of cardiac computed tomography in pre-participation screening of mature athletes

The overwhelming majority of sports-related sudden cardiac deaths in mature athletes is attributed to coronary artery disease (CAD). Coronary plaques of mature athletes appear to be more calcified compared to sedentary individuals and thus may be more stable and less likely to be associated with an acute coronary event. Cardiac computed tomography (CT), including unenhanced CT for coronary artery calcium scoring (CACS) and contrast-enhanced coronary CT angiography, is characterized by very high negative predictive value to rule out CAD. Cardiac CT has been shown to have additional diagnostic value for detection of CAD in athletes over and above exercise electrocardiogram. Moreover, measurement of CACS possibly enables a more precise cardiovascular risk stratification of mature athletes. The main advantage of cardiac CT is its noninvasive nature. Although cardiac CT appears to increase the overall cost of cardiac examinations, this additional cost is much lower than the cost of unnecessary invasive coronary angiographies that would be performed in case of false positive results of exercise electrocardiograms. Radiation exposure may not be a major concern for the application of this modality to pre-participation screening of athletes, since recent technical advancements have resulted in low radiation dose of cardiac CT.Highlights Coronary computed tomography angiography can be used in pre-participation screening of mature athletes to increase the negative predictive value for excluding coronary artery disease.The identification of coronary artery calcium score = 0 in an athlete can improve risk stratification, since this athlete can be reasonably managed as an individual with low cardiovascular risk.

Influence of exercise test on platelet function in patients with coronary arterial disease: A systematic review

BACKGROUND

Exercise test (ET) may have adverse effects on platelet function and induce acute thrombotic events in patients with coronary artery disease (CAD). The aim of this study is to investigate the platelet function and evaluate the risk of thrombotic events in CAD patients during ET.

METHODS

Pubmed, Embase, Cochrane Library, and Web of Science were searched for a systematic review from initiation to October 2019. The inclusion criteria were controlled clinical trails as study design; investigating platelet function in CAD patients during ET; with ET carried out by treadmill or bicycle ergometer; written in English. Included articles were screened based on title/abstract and full-text review by 2 independent reviewers. Platelet aggregation (PA), platelet surface expression of CD62p and PAC-1, plasma levels of platelet factor 4 (PF4) and beta-thromboglobulin (β-TG) were evaluated before and after ET.

RESULTS

Eighteen articles were included out of the 427 references initially identified. In most of the studies included ET was terminated because of limited symptoms. Prior to ET, no difference in platelet aggregation was observed in CAD patients compared with healthy controls in majority of the studies, with or without the treatment with Aspirin. Dual anti-platelet therapy suppressed adenosine diphosphate (ADP)-induced platelet aggregation at rest. After ET, platelet aggregation, the serum levels of β-thromboglobulin were found unchanged in majority of studies and platelet factor-4 were found unchanged in half of studies. The expression of platelet surface markers were elevated by ET in a few study.

CONCLUSION

Symptom-limited exercise test did not affect platelet function in patients with coronary artery disease; however exercise to higher intensity may induce platelet activation.

Vascular imaging of atherosclerosis: Strengths and weaknesses

Atherosclerosis is an inflammatory disease that can lead to several complications such as ischemic heart disease, stroke, and peripheral vascular disease. Therefore, researchers and clinicians rely heavily on the use of imaging modalities to identify, and more recently, quantify the burden of atherosclerosis in the aorta, carotid arteries, coronary arteries, and peripheral vasculature. These imaging techniques vary in invasiveness, cost, resolution, radiation exposure, and presence of artifacts. Consequently, a detailed understanding of the risks and benefits of each technique is crucial prior to their introduction into routine cardiovascular screening. Additionally, recent research in the field of microvascular imaging has proven to be important in the field of atherosclerosis. Using techniques such as contrast-enhanced ultrasound and superb microvascular imaging, researchers have been able to detect blood vessels within a plaque lesion that may contribute to vulnerability and rupture. This paper will review the strengths and weaknesses of the various imaging techniques used to measure atherosclerotic burden. Furthermore, it will discuss the future of advanced imaging modalities as potential biomarkers for atherosclerosis.

Factors associated with long-term major adverse cardiac events of coronary bioresorbable vascular scaffold

The long-term clinical outcomes after implantation of bioresorbable vascular scaffolds (BVS) in a real-world cohort were not well described. To identify factors associated with major adverse cardiovascular events (MACE) on long-term follow-up after implantation of BVS in patients undergoing elective percutaneous coronary intervention (PCI). This was an observational study based on a hospital registry of percutaneous coronary intervention. Participants were consecutive patients who underwent PCI and implanted with at least one everolimus-eluting BVS (Absorb^®) in a single center between 2014 and 2017. Among the 170 cases analyzed (mean age 60.4 ± 10.7), a total of 203 Absorb BVS were implanted. MACE developed in 33 (19.4%) patients over a median follow-up period of 61 months, including 9 (5.3%) deaths, 13 (7.6%) non-fatal myocardial infarction and 19 (11.2%) ischemia driven target vessel revascularization. Definite or probable stent thrombosis developed in 4 (2.4%) patients. In crude analysis, history of smoking and initial presentation of non-ST elevation-acute coronary syndrome (NSTE-ACS) were predictors of long-term MACE. In adjusted analysis, presentation with NSTE-ACS was an independent predictor of long-term MACE [adjusted odds ratio (OR) 4.52; 95% confidence interval (95% CI) 1.50 to 13.6, P = 0.007]. Among patients receiving implantation of ABSORB BVS, presentation with NSTE-ACS was an independent predictor of MACE after a median follow-up period of 61 months. Future research is needed to confirm these findings and to determine the long-term safety of BVS in patients with NSTE-ACS.

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.

The role of intracoronary imaging in translational research

Atherosclerotic cardiovascular disease is a key public health concern worldwide and leading cause of morbidity, mortality and health economic costs. Understanding atherosclerotic plaque microstructure in relation to molecular mechanisms that underpin its initiation and progression is needed to provide the best chance of combating this disease. Evolving vessel wall-based, endovascular coronary imaging modalities, including intravascular ultrasound (IVUS), optical coherence tomography (OCT) and near-infrared spectroscopy (NIRS), used in isolation or as hybrid modalities, have been advanced to allow comprehensive visualization of the pathological substrate of coronary atherosclerosis and accurately measure temporal changes in both the vessel wall and plaque characteristics. This has helped further our appreciation of the natural history of coronary artery disease (CAD) and the risk for major adverse cardiovascular events (MACE), evaluate the responsiveness to conventional and experimental therapeutic interventions, and assist in guiding percutaneous coronary intervention (PCI). Here we review the use of different imaging modalities for these purposes and the lessons they have provided thus far.

Inflammation in Coronary Atherosclerosis and Its Therapeutic Implications

Atherosclerotic coronary artery disease has a complex pathogenesis which extends beyond cholesterol intimal infiltration. It involves chronic inflammation of the coronary artery wall driven by systemic and local activation of both the adaptive and innate immune systems, which can ultimately result in the rupture or erosion of atherosclerotic plaque, leading to thrombosis and myocardial infarction (MI). Despite current best practice care, including the widespread use of cholesterol-lowering statins, atherothrombotic cardiovascular events recur at alarming rates post-MI. To a large extent, this reflects residual inflammation that is not adequately controlled by contemporary treatment. Consequently, there has been increasing interest in the pharmacological targeting of inflammation to improve outcomes in atherosclerotic cardiovascular disease. This has comprised both novel pathway-specific agents, most notably the anti-interleukin-1 beta monoclonal antibody, canakinumab, and the repurposing of established, broad-acting drugs, such as colchicine, that are already approved for the management of other inflammatory conditions. Here we discuss the importance of inflammation in mediating atherosclerosis and its complications and provide a timely update on "new" and "old" anti-inflammatory therapies currently being investigated to target it.

Change in matrix metalloproteinase 2, 3, and 9 levels at the time of and after acute atherothrombotic myocardial infarction

Elevated measures of matrix metalloproteinases (MMPs) are associated with acute myocardial infarction (MI), but it is not known how long these changes persist post-MI or if these measures differ between atherothrombotic versus non-atherothrombotic MI. MMPs-2, 3, and 9 were measured in 80 subjects with acute MI (atherothrombotic and non-atherothrombotic MI) or stable coronary artery disease (CAD). Measurements were made at, the time of acute MI, and > 3-month following acute MI (quiescent phase). Outcome measures were compared between groups and between time of acute MI and quiescent post-MI follow-up using Wilcoxon's and repeated measures analysis of variance. Forty-nine subjects met the criteria for acute MI with clearly defined atherothrombotic (n = 22) and non-atherothrombotic (n = 12) subsets. Fifteen subjects met criteria for stable CAD. MMP-3 was higher in acute MI versus stable CAD subjects at the time of acute MI: (453 vs. 217 pg/mL, p = 0.010) but not at quiescent phase follow-up (p > 0.05). MMP-9 was higher in acute MI versus stable CAD subjects at the time of acute MI: (412 vs. 168 pg/mL, p = 0.002) but not at the quiescent phase follow-up (p > 0.05). MMP-9 was higher at the time of acute MI versus quiescent phase follow-up in acute MI (412 vs. 213 pg/mL, p = 0.001) and atherothrombotic MI specifically (458 vs. 212 pg/mL, p = 0.001). No difference in MMP-2, 3, or 9 was observed between atherothrombotic versus non-atherothrombotic MI subgroups. MMPs-3 and 9 are significantly elevated in acute MI verses stable CAD subjects at time of acute MI but not different at quiescent phase follow-up. MMP-9 is elevated at the time of acute MI and specifically in acute atherothrombotic MI at time of MI versus quiescent phase follow-up.

In-hospital morality associated with acute myocardial infarction was inversely related with the number of coronary risk factors in patients from a Japanese nation-wide real-world database

BACKGROUND

Hypertension, diabetes, dyslipidemia and smoking are established coronary risk factors for coronary heart disease in the general population. However, in Japanese patients with acute myocardial infarction (AMI), the impact of the number of coronary risk factors on in-hospital morality remains unclear.

METHODS

The Japan Acute Myocardial Infarction Registry (JAMIR) is a nationwide real-world database. We examined the association between the number of coronary risk factors and in-hospital mortality.

RESULTS

Data were obtained from total of 20462 AMI patients (mean age, 68.8 ± 13.3 years old; 15281 men, 5181 women). The prevalence of hypertension increased with advancing age, while the prevalence of smoking decreased with advancing age. The prevalence of diabetes and dyslipidemia were highest in middle age. A majority (76.9%) of the patients with AMI had at least 1 of these coronary risk factors. Overall, the number of coronary risk factor was relatively less in older subjects and women under 50 years old. Crude in-hospital mortality rates were 10.7%, 10.5%, 7.2%, 5.0% and 4.5% with 0, 1, 2, 3 and 4 risk factors, respectively. After adjusting for age and sex, there was an inverse association between the number of coronary risk factors and the in-hospital mortality (adjusted odds ratio [1.68; 95% confidence interval, 1.20-2.35] among individuals with 0 vs. 4 risk factors).

CONCLUSION

In the present study of Japanese patients with AMI, who received modern medical treatment, in-hospital mortality was inversely related to the number of coronary risk factors. To investigate the underlying reasons for these findings, further studies are needed.

Insight from imaging on plaque vulnerability: similarities and differences between coronary and carotid arteries-implications for systemic therapies

Nowadays it is widely accepted that the rupture of the atherosclerotic plaque in coronary and carotid arteries plays a fundamental role in the development of acute myocardial infarctions or cerebrovascular events. In recent years, imaging techniques have explored, with a new level of detail, the atherosclerotic disease generating new evidences that some plaque characteristics are significantly associated to the risk of rupture and subsequent thrombosis or embolization. Moreover, the recent evidence of the anti-atherosclerotic effects determined by lipid-lowering and anti-inflammatory therapies poses a challenge for the choice of therapeutic approaches (best/optimal medical therapy vs. revascularization), maximized by the evidence that coronary and carotid atherosclerosis share common patterns but also differ regarding some important features. In this Review, we discuss the similarities and differences between coronary and carotid artery vulnerable plaque from the imaging point of view and the potential implications for systemic therapies according to the emerging evidence.

Snowfall, Temperature, and the Risk of Death From Myocardial Infarction: A Case-Crossover Study

Previous research has associated snowfall with risk of myocardial infarction (MI). Most studies have been conducted in regions with harsh winters; it remains unclear whether snowfall is associated with risk of MI in regions with milder or more varied climates. A case-crossover design was used to investigate the association between snowfall and death from MI in British Columbia, Canada. Deaths from MI among British Columbia residents between October 15 and March 31 from 2009 to 2017 were identified. The day of each death from MI was treated as the case day, and each case day was matched to control days drawn from the same day of the week during the same month. Daily snowfall amount was assigned to case and control days at the residential address, using weather stations within 15 km of the residence and 100 m in elevation. In total, 3,300 MI case days were matched to 10,441 control days. Compared with days that had no snowfall, odds of death from MI increased 34% (95% confidence interval: 0%, 80%) on days with heavy snowfall (≥5 cm). In stratified analysis of deaths from MI as a function of both maximum temperature and snowfall, risk was significantly increased on snowfall days when the temperature was warmer.

Optical Coherence Tomography for the Diagnosis of Exercise-Related Acute Cardiovascular Events and Inconclusive Coronary Angiography

Objectives

The aim of this study is to assess the utility of optical coherence tomography (OCT) in patients with exercise-related acute coronary syndrome (ACS) presenting with inconclusive angiographic findings.

Background

Regular physical activity reduces the incidence of cardiovascular events. Nevertheless, the risk of ACS or sudden cardiac death (SCD) increases during sport. In adults older than 35 years, exercise-related ACS or SCD is associated with plaque rupture, but not infrequently patients present ambiguous angiographic findings.

Methods

Between September 2015 and January 2020, patients admitted for ACS or SCD triggered by physical exertion and with coronary stenosis ≤50% were included in this prospective observational study. OCT was performed on the artery deemed to be responsible of the event.

Results

Ten patients were enrolled, predominantly men (80%) of middle age (51 years old, IQR 41–63) with low cardiovascular risk burden. Cycling was the most frequent (50%) exercise-related trigger, 8 patients were regular sport practitioners, and 7 had the clinical event during strenuous exertion. Five patients presented with non-ST-elevation ACS, two with ST-elevation ACS, and three with SCD. Angiographic analysis showed nonsignificant stenosis in all patients (42% stenosis, IQR 36–46). OCT identified the etiology of the event in 9 patients (4 plaque erosion, 3 plaque rupture, 1 eruptive calcific nodule, and 1 coronary dissection). Treatment was adjusted according to OCT findings.

Conclusions

OCT is a valuable technique to identify the etiology of exercise-related ACS or SCD in patients with nonobstructive coronary arteries and, as a result, may lead to a more specific treatment.

Exploring the relationship between biomechanical stresses and coronary atherosclerosis

The pathophysiology of coronary atherosclerosis is multifaceted. Plaque initiation and progression are governed by a complex interplay between genetic and environmental factors acting through processes such as lipid accumulation, altered haemodynamics and inflammation. There is increasing recognition that biomechanical stresses play an important role in atherogenesis, and integration of these metrics with clinical imaging has potential to significantly improve cardiovascular risk prediction. In this review, we present the calculation of coronary biomechanical stresses from first principles and computational methods, including endothelial shear stress (ESS), plaque structural stress (PSS) and axial plaque stress (APS). We discuss the current experimental and human data linking these stresses to the natural history of coronary artery disease and explore the future potential for refining treatment options and predicting future ischaemic events.

Accelerated miniature swine models of advanced atherosclerosis: A review based on morphology

In order to accelerate development of atherosclerosis(AS) in miniature swine models, varieties of strategies and methods have been explored. In addition to traditional methods such as high cholesterol feeding and balloon injury, new methods such as familial hypercholesterolemia induced by gene editing and intramural injection have been applied in recent years. Although it has been claimed that these methods have successfully aggravated lesion areas and stenosis, lesion features induced by different strategies have shown heterogeneity in morphology. In addition, time consumption, high cost, and unavailability are problems that restrict application of these AS models. Here, we summarize strategies and methods to accelerate AS models and further analyze their values, advantages, and shortcomings.

Should fractional flow reserve follow angiographic visual inspection to guide preventive percutaneous coronary intervention in ST-elevation myocardial infarction?

Aims

We aimed to quantify the effect of preventive percutaneous coronary intervention (PCI to non-infarct arteries) on cardiac death and non-fatal myocardial infarction (MI) in patients with ST-elevation myocardial infarction (STEMI) according to whether the decision to carry out preventive PCI was based on angiographic visual inspection (AVI alone) or AVI plus fractional flow reserve (FFR) if AVI showed significant stenosis (AVI plus FFR).

Methods and results

Randomized trials comparing preventive PCI with no preventive PCI in STEMI without shock were identified by a systematic literature search and categorized according to whether they used AVI alone or AVI plus FFR to select patients for preventive PCI. Random effects meta-analyses and tests of heterogeneity were used to compare the two categories in respect of cardiac death and MI as a combined outcome and individually. Eleven eligible trials were identified. For cardiac death and MI, the relative risk estimates for AVI alone vs. AVI plus FFR were 0.39 (0.25–0.61) and 0.85 (0.57–1.28), respectively (P = 0.01 for difference), for cardiac death, alone the estimates were 0.36 (0.19–0.71) and 0.79 (0.36–1.77), respectively (P = 0.15 for difference), and for MI alone, 0.41 (0.23–0.73) and 0.98 (0.62–1.56), respectively (P = 0.04 for difference).

Conclusion

In preventive PCI among STEMI patients, AVI alone achieves a ∼60% reduction in cardiac death and MI but selecting patients using FFR in AVI positive patients loses much of the benefit. Angiographic visual inspection is best used without FFR in this group of patients.