Comparison of thrombogenicity in different types of drug-eluting stents during transition from DAPT to SAPT

BACKGROUND

During the transition from dual antiplatelet therapy (DAPT) to single antiplatelet therapy (SAPT), previous studies have raised concerns about a rebound effect. We compared platelet and inflammatory cell adhesion on different types of stents in the setting of clopidogrel presence and withdrawal.

METHODS

In Experiment 1, three pigs were administered with DAPT, that is, clopidogrel and acetylsalicylic acid (ASA), for 7 days. Each animal underwent an extracorporeal carotid arteriovenous shunt model implanted with fluoropolymer-coated everolimus-eluting stent (FP-EES), biodegradable-polymer sirolimus-eluting stent (BP-SES), and biodegradable-polymer everolimus-eluting stents (BP-EES). In Experiment 2, two pigs were administered DAPT, clopidogrel was then withdrawn at day 7, and SAPT with ASA was continued for next 21 days. Then flow-loop experiments with the drawn blood from each time point were performed for FP-EES, BioLinx-polymer zotarolimus-eluting stents (BL-ZES), and BP-EES. The rebound effect was defined as the statistical increase of inflammation and platelet adhesion assessed with immunohistochemistry on the stent-strut level basis from baseline to day-14 or 28.

RESULTS

Both experiments showed platelet adhesion value was highest in BP-EES, while the least in FP-EES during DAPT therapy. There was no increase in platelet or inflammatory cell adhesion above baseline values (i.e., no therapy) due to the cessation of clopidogrel on the stent-strut level. Monocyte adhesion was the least for FP-EES with the same trend observed for neutrophil adhesion.

CONCLUSIONS

No evidence of rebound effect was seen after the transition from DAPT to SAPT. FP-EES demonstrated the most favorable antithrombotic and anti-inflammatory profile regardless of the different experimental designs.

Effect of EDTA with porous balloon on calcified lesion: An atherosclerotic cadaver study

BACKGROUND

Ethylene diamine tetra-acetic acid (EDTA) is a chelating agent used to dissolve calcium deposits but evidence in decalcifying atherosclerotic lesions is limited.

AIMS

We assessed the feasibility and efficacy of EDTA delivered via porous balloon to target calcified lesions in cadaveric below-the-knee (BTK) arteries.

METHODS

Using porcine carotid arteries, EDTA concentration was measured in the arterial wall and outside the artery at the 0-, 0.5-, 4-, and 24-h circulation after the injection through a porous balloon. In cadaver BTK samples, the proximal and distal anterior tibial artery (ATA) and distal posterior tibial artery (PTA) were studied. EDTA-2Na/H2O or EDTA-3Na/H2O were administrated using a porous balloon, then circulated for 6 h for EDTA-3Na/H2O and 24 h for EDTA-2Na/H2O and EDTA-3Na/H2O. Micro-CT imaging of the artery segments before and after the circulation and cross-sectional analyses were performed to evaluate calcium burden.

RESULTS

In the porcine carotid study, EDTA was delivered through a porous balloon present in the arterial wall and was retained there for 24 h. In BTK arteries, cross-sectional analyses of micro-CT revealed a significant decrease in the calcium area in the distal ATA segment under 24-h circulation with EDTA-2Na/H2O and in the distal ATA segment under 24-h circulation with EDTA-3Na/H2O. The proximal ATA segment under 6-h circulation with EDTA-3Na/H2O showed no significant change in any parameters of calcium CONCLUSION: EDTA-3Na/H2O or EDTA-2Na/H2O with longer circulation times resulted in greater calcium reduction in atherosclerotic lesion. EDTA may have a potential therapeutic option for the treatment of atherosclerotic calcified lesions.

Long-Term Effects of COVID-19 on the Cardiopulmonary System in Adults and Children: Current Status and Questions to be Resolved by the National Institutes of Health Researching COVID to Enhance Recovery Initiative

TOPIC IMPORTANCE

Long COVID may occur in at least 10% of patients recovering from SARS-CoV-2 infection and often is associated with debilitating symptoms. Among the organ systems that might be involved in its pathogenesis, the respiratory and cardiovascular systems may be central to common symptoms seen in survivors of COVID-19, including fatigue, dyspnea, chest pain, cough, and exercise intolerance. Understand the exact symptomatology, causes, and effects of long COVID on the heart and lungs may help us to discover new therapies. To that end, the National Institutes of Health is sponsoring a national study population of diverse volunteers to support large-scale studies on the long-term effects of COVID-19.

REVIEW FINDINGS

The National Institutes of Health Researching COVID to Enhance Recovery (RECOVER) initiative currently is recruiting participants in the United States to answer critical questions about long COVID. The study comprises adult and pediatric cohorts as well as an electronic health record cohort. Based on symptoms, individuals undergo prespecified medical testing to understand whether abnormalities can be detected and are followed up longitudinally. Herein, we outline current understanding of the clinical symptoms and pathophysiologic features of long COVID with respect to the cardiopulmonary system in adults and children and then determine how the clinical, electronic health record, and autopsy cohorts of the RECOVER initiative will attempt to answer the most pressing questions surrounding the long-term effects of COVID-19.

SUMMARY

Data generated from the RECOVER initiative will provide guidance about missing gaps in our knowledge about long COVID and how they might be filled by data gathered through the RECOVER initiative.

Recurrent Stent Thrombosis Following Myocardial Infarction Associated With VITT-Like Antibodies

Early stent thrombosis is a rare complication of percutaneous intervention and is associated with significant 30-day mortality. We present a novel case of multiple recurrent early stent thrombosis consistent with spontaneous vaccine-induced thrombotic thrombocytopenia. We were successfully able to manage this unusual condition through an interdisciplinary collaboration.

Spontaneous Coronary Artery Dissection Resulting in Acute Myocardial Infarction With Cardiac Rupture

Spontaneous coronary artery dissection occurs predominantly in women and is associated with fibromuscular dysplasia. We illustrate a rare case of sudden coronary death as a result of cardiac rupture from spontaneous coronary artery dissection in a 54-year-old man without fibromuscular dysplasia. Cardiac rupture has been previously reported in 6 cases, mostly in women.

Researching COVID to enhance recovery (RECOVER) tissue pathology study protocol: Rationale, objectives, and design

IMPORTANCE

SARS-CoV-2 infection can result in ongoing, relapsing, or new symptoms or organ dysfunction after the acute phase of infection, termed Post-Acute Sequelae of SARS-CoV-2 (PASC), or long COVID. The characteristics, prevalence, trajectory and mechanisms of PASC are poorly understood. The objectives of the Researching COVID to Enhance Recovery (RECOVER) tissue pathology study (RECOVER-Pathology) are to: (1) characterize prevalence and types of organ injury/disease and pathology occurring with PASC; (2) characterize the association of pathologic findings with clinical and other characteristics; (3) define the pathophysiology and mechanisms of PASC, and possible mediation via viral persistence; and (4) establish a post-mortem tissue biobank and post-mortem brain imaging biorepository.

METHODS

RECOVER-Pathology is a cross-sectional study of decedents dying at least 15 days following initial SARS-CoV-2 infection. Eligible decedents must meet WHO criteria for suspected, probable, or confirmed infection and must be aged 18 years or more at the time of death. Enrollment occurs at 7 sites in four U.S. states and Washington, DC. Comprehensive autopsies are conducted according to a standardized protocol within 24 hours of death; tissue samples are sent to the PASC Biorepository for later analyses. Data on clinical history are collected from the medical records and/or next of kin. The primary study outcomes include an array of pathologic features organized by organ system. Causal inference methods will be employed to investigate associations between risk factors and pathologic outcomes.

DISCUSSION

RECOVER-Pathology is the largest autopsy study addressing PASC among US adults. Results of this study are intended to elucidate mechanisms of organ injury and disease and enhance our understanding of the pathophysiology of PASC.

Nonbacterial Thrombotic Endocarditis Caused by Early-stage Lung Cancer: An Autopsy Case Report

Nonbacterial thrombotic endocarditis (NBTE) is a manifestation of prothrombotic status observed in patients with malignancy. Most cases are discovered only in the advanced stages. However, cancer in early stages may also induce NBTE development. We herein report an 87-year-old man with NBTE with multiple thromboembolization coexisting with lung cancer in early clinical stage. Autopsy findings revealed platelet- and fibrin-rich vegetations in both the tricuspid and mitral valves without evidence of bacterial infection. NBTE should be considered in cases with occult thromboembolization. Not only the presence of typical vegetation but irregular leaflet thickening should be monitored with careful echocardiographic examinations.

Subclinical Atherosclerosis: Part 1: What Is it? Can it Be Defined at the Histological Level?

While coronary artery disease remains a major cause of death, it is preventable. Therefore, the focus needs to shift to the early detection and prevention of atherosclerosis. Asymptomatic atherosclerosis is widely termed subclinical atherosclerosis, which is an early indicator of atherosclerotic burden, and understanding this disease is important because timely intervention could prevent future cardiovascular morbidity and mortality. We histologically recognize the earliest lesion of atherosclerosis as pathological intimal thickening, which is characterized by the presence of lipid pools. The difference between clinical atherosclerosis and subclinical atherosclerosis is whether the presence of atherosclerosis results in the clinical symptoms of ischemia, such as stroke, myocardial infarction, or chronic limb-threatening ischemia. In the absence of thrombosis, there are various types of histological plaque that encompass subclinical atherosclerosis: pathological intimal thickening, fibroatheroma, thin-cap fibroatheroma, plaque rupture, healed plaque ruptures, and fibrocalcific plaque. Plaque morphology that is most frequently responsible for acute coronary thrombosis is plaque rupture. Calcification of coronary arteries is the hallmark of atherosclerosis and is a predictor of future coronary events. Atherosclerosis occurs in other vascular beds and is most frequent in arteries of the lower extremity, followed by carotid, aorta, and coronary arteries, and the mechanisms leading to clinical symptoms are unique for each location.

Polygenic Risk Score Associates With Atherosclerotic Plaque Characteristics at Autopsy

BACKGROUND

Polygenic risk scores (PRSs) for coronary artery disease (CAD) potentially improve cardiovascular risk prediction. However, their relationship with histopathologic features of CAD has never been examined systematically.

METHODS

From 4327 subjects referred to CVPath by the State of Maryland Office Chief Medical Examiner for sudden death between 1994 and 2015, 2455 cases were randomly selected for genotyping. We generated PRS from 291 known CAD risk loci. Detailed histopathologic examination of the coronary arteries was performed in all subjects. The primary study outcome measurements were histopathologic plaque features determining severity of atherosclerosis, including %stenosis, calcification, thin-cap fibroatheromas, and thrombotic CAD.

RESULTS

After exclusion of cases with insufficient DNA sample quality or with missing data, 954 cases (mean age, 48.8±14.7 years; 75.7% men) remained in the final study cohort. Subjects in the highest PRS quintile exhibited more severe atherosclerosis compared with subjects in the lowest quintile, with greater %stenosis (80.3%±27.0% versus 50.4%±38.7%; adjusted P<0.001) and a higher frequency of calcification (69.6% versus 35.8%; adjusted P=0.004) and thin-cap fibroatheroma (26.7% versus 9.5%; adjusted P=0.007). Even after adjustment for traditional CAD risk factors, subjects within the highest PRS quintile had higher odds of severe atherosclerosis (ie, ≥75% stenosis; adjusted odds ratio, 3.77 [95% CI, 2.10-6.78]; P<0.001) and plaque rupture (adjusted odds ratio, 4.05 [95% CI, 2.26-7.24]; P<0.001). Moreover, subjects within the highest quintile had higher odds of CAD-associated cause of death, especially among those aged ≤50 years (adjusted odds ratio, 4.08 [95% CI, 2.01-8.30]; P<0.001). No statistically significant associations were observed with plaque erosion after adjusting for covariates.

CONCLUSIONS

This is the first autopsy study investigating associations between PRS and atherosclerosis severity at the histopathologic level in subjects with sudden death. Our pathological analysis suggests PRS correlates with plaque burden and features of advanced atherosclerosis and may be useful as a method for CAD risk stratification, especially in younger subjects.

First-in-human study of the CAPTIS embolic protection system during transcatheter aortic valve replacement

BACKGROUND

Stroke and other clinically significant embolic complications are well documented in the early period following transcatheter aortic valve replacement (TAVR). The CAPTIS device is an embolic protection system, designed to provide neurovascular and systemic protection by deflecting debris away from the brain's circulation, capturing the debris and thus avoiding systemic embolisation.

AIMS

We aimed to study the safety and feasibility study of the CAPTIS complete cerebral and full-body embolic protection system during TAVR.

METHODS

A first-in-human study investigated the safety, feasibility and debris capturing ability of CAPTIS during TAVR. Patients were followed for 30 days. The primary endpoints were device safety and cerebrovascular events at 72 hours.

RESULTS

Twenty patients underwent TAVR using balloon-expandable or self-expanding valve systems. CAPTIS was successfully delivered, positioned, deployed, and retrieved in all cases, and TAVR was successfully completed without device-related complications. No cerebrovascular events were observed. High numbers of debris particles were captured in all patients.

CONCLUSIONS

The use of the CAPTIS full-body embolic protection system during TAVR was safe, and it captured a substantial number of debris particles. No patient suffered from a cerebrovascular event. A randomised clinical trial is warranted to prove its efficacy.

Clonal Proliferation Within Smooth Muscle Cells in Unstable Human Atherosclerotic Lesions

BACKGROUND

Studies in humans and mice using the expression of an X-linked gene or lineage tracing, respectively, have suggested that clones of smooth muscle cells (SMCs) exist in human atherosclerotic lesions but are limited by either spatial resolution or translatability of the model.

METHODS

Phenotypic clonality can be detected by X-chromosome inactivation patterns. We investigated whether clones of SMCs exist in unstable human atheroma using RNA in situ hybridization (BaseScope) to identify a naturally occurring 24-nucleotide deletion in the 3'UTR of the X-linked BGN (biglycan) gene, a proteoglycan highly expressed by SMCs. BGN-specific BaseScope probes were designed to target the wild-type or deletion mRNA. Three different coronary artery plaque types (erosion, rupture, and adaptive intimal thickening) were selected from heterozygous females for the deletion BGN. Hybridization of target RNA-specific probes was used to visualize the spatial distribution of mutants. A clonality index was calculated from the percentage of each probe in each region of interest. Spatial transcriptomics were used to identify differentially expressed transcripts within clonal and nonclonal regions.

RESULTS

Less than one-half of regions of interest in the intimal plaque were considered clonal with the mean percent regions of interest with clonality higher in the intimal plaque than in the media. This was consistent for all plaque types. The relationship of the dominant clone in the intimal plaque and media showed significant concordance. In comparison with the nonclonal lesions, the regions with SMC clonality had lower expression of genes encoding cell growth suppressors such as CD74, SERF-2 (small EDRK-rich factor 2), CTSB (cathepsin B), and HLA-DPA1 (major histocompatibility complex, class II, DP alpha 1), among others.

CONCLUSIONS

Our novel approach to examine clonality suggests atherosclerosis is primarily a disease of polyclonally and to a lesser extent clonally expanded SMCs and may have implications for the development of antiatherosclerotic therapies.

Treatment effect of medial arterial calcification in below-knee after Auryon laser atherectomy using micro-CT and histologic evaluation

PURPOSE

To determine the frequency of medial arterial calcification (MAC) fracture following Auryon laser atherectomy using micro-CT and histologic evaluation in an atherosclerotic human cadaveric limb model.

METHODS

Two below-the-knee calcified arterial segments from human cadaver limbs underwent treatment with the Auryon laser system with or without plain old balloon angioplasty (POBA). Micro-CT and angiography were performed before and after treatment followed by histological evaluation of regions showing calcium disruption.

RESULTS

All treatment zones were successfully treated with the Auryon laser (n = 9). Six of 9 treatment zones showed calcium fracture on micro-CT. Each treatment zone was further subdivided using micro-CT analysis (36 evaluated sections) of which 18 sections revealed calcium fracture. Sections with calcium fracture had significantly more confluent and uninterrupted circumferential calcification than sections without calcium fracture (arc of calcification 360.0 [323.7-360.0] vs 312.8 [247.4-314.2] degree, p = 0.007), whereas there were no differences in size of calcium burden (3.4 [2.8-3.9] vs 2.8 [1.3-4.6] mm2, p = 0.46). No arterial dissection or rupture was seen.

CONCLUSIONS

Auryon laser atherectomy produced fractures of medial arterial calcification in this cadaveric human atherosclerotic peripheral artery model. This effect was observed in arterial segments with a pattern of circumferential uninterrupted calcification (i.e. larger arc of calcification) regardless of calcium burden. Our pilot data suggests Auryon laser may be a promising therapy for calcified lesions.

Plaque histological characteristics in individuals with sudden coronary death

Coronary artery disease (CAD) remains the leading cause of death in the Western world in individuals >20 years of age. CAD is the most common substrate underlying sudden cardiac death (SCD) in the Western world, being responsible for 50-75% of SCDs. In individuals dying suddenly with coronary thrombosis, plaque rupture occurs in 65%, plaque erosion in 30% and calcified nodule in 5%. We evaluated the extent of calcification in radiographs of hearts from patients dying of SCD and showed that calcification is absent in nearly 50% of erosion cases whereas only 10% of plaque rupture show no calcification. Conversely, stable plaques with >75% cross-sectional area luminal narrowing show the severest calcification (moderate to severe) in nearly 50% of cases. Identifying individuals who are susceptible to atherosclerosis may help reduce the incidence of SCD. The identification of coronary calcifications by noninvasive tools, however, only captures a fraction of complicating coronary lesions.

Integrative single-cell meta-analysis reveals disease-relevant vascular cell states and markers in human atherosclerosis

Coronary artery disease (CAD) is characterized by atherosclerotic plaque formation in the arterial wall. CAD progression involves complex interactions and phenotypic plasticity among vascular and immune cell lineages. Single-cell RNA-seq (scRNA-seq) studies have highlighted lineage-specific transcriptomic signatures, but human cell phenotypes remain controversial. Here, we perform an integrated meta-analysis of 22 scRNA-seq libraries to generate a comprehensive map of human atherosclerosis with 118,578 cells. Besides characterizing granular cell-type diversity and communication, we leverage this atlas to provide insights into smooth muscle cell (SMC) modulation. We integrate genome-wide association study data and uncover a critical role for modulated SMC phenotypes in CAD, myocardial infarction, and coronary calcification. Finally, we identify fibromyocyte/fibrochondrogenic SMC markers (LTBP1 and CRTAC1) as proxies of atherosclerosis progression and validate these through omics and spatial imaging analyses. Altogether, we create a unified atlas of human atherosclerosis informing cell state-specific mechanistic and translational studies of cardiovascular diseases.

The accumulation of erythrocytes quantified and visualized by Glycophorin C in carotid atherosclerotic plaque reflects intraplaque hemorrhage and pre-procedural neurological symptoms

The accumulation of erythrocyte membranes within an atherosclerotic plaque may contribute to the deposition of free cholesterol and thereby the enlargement of the necrotic core. Erythrocyte membranes can be visualized and quantified in the plaque by immunostaining for the erythrocyte marker glycophorin C. Hence, we theorized that the accumulation of erythrocytes quantified by glycophorin C could function as a marker for plaque vulnerability, possibly reflecting intraplaque hemorrhage (IPH), and offering predictive value for pre-procedural neurological symptoms. We employed the CellProfiler-integrated slideToolKit workflow to visualize and quantify glycophorin C, defined as the total plaque area that is positive for glycophorin C, in single slides of culprit lesions obtained from the Athero-Express Biobank of 1819 consecutive asymptomatic and symptomatic patients who underwent carotid endarterectomy. Our assessment included the evaluation of various parameters such as lipid core, calcifications, collagen content, SMC content, and macrophage burden. These parameters were evaluated using a semi-quantitative scoring method, and the resulting data was dichotomized as predefined criteria into categories of no/minor or moderate/heavy staining. In addition, the presence or absence of IPH was also scored. The prevalence of IPH and pre-procedural neurological symptoms were 62.4% and 87.1%, respectively. The amount of glycophorin staining was significantly higher in samples from men compared to samples of women (median 7.15 (IQR:3.37, 13.41) versus median 4.06 (IQR:1.98, 8.32), p < 0.001). Glycophorin C was associated with IPH adjusted for clinical confounders (OR 1.90; 95% CI 1.63, 2.21; p =  < 0.001). Glycophorin C was significantly associated with ipsilateral pre-procedural neurological symptoms (OR:1.27, 95%CI:1.06-1.41, p = 0.005). Sex-stratified analysis, showed that this was also the case for men (OR 1.37; 95%CI 1.12, 1.69; p = 0.003), but not for women (OR 1.15; 95%CI 0.77, 1.73; p = 0.27). Glycophorin C was associated with classical features of a vulnerable plaque, such as a larger lipid core, a higher macrophage burden, less calcifications, a lower collagen and SMC content. There were marked sex differences, in men, glycophorin C was associated with calcifications and collagen while these associations were not found in women. To conclude, the accumulation of erythrocytes in atherosclerotic plaque quantified and visualized by glycophorin C was independently associated with the presence of IPH, preprocedural symptoms in men, and with a more vulnerable plaque composition in both men and women. These results strengthen the notion that the accumulation of erythrocytes quantified by glycophorin C can be used as a marker for plaque vulnerability.

Histology, OCT, and Micro-CT Evaluation of Coronary Calcification Treated With Intravascular Lithotripsy: Atherosclerotic Cadaver Study

BACKGROUND

Although intravascular lithotripsy (IVL) has been an emerging novel option to treat vascular calcification, the specific effects on histology have not been systematically examined.

OBJECTIVES

The authors examined the histologic effects of IVL on coronary calcified lesions from human autopsy hearts and evaluated the diagnostic ability of optical coherence tomography (OCT) and micro-computed tomography (CT) to detect calcium fracture as identified by the gold standard histology.

METHODS

Eight coronary lesions were treated with IVL, and 7 lesions were treated with 10 atm inflation using an IVL catheter balloon without lithotripsy pulses (plain old balloon angioplasty [POBA]). OCT and micro-CT imaging were performed before and after treatment, and the presence of calcium fracture was assessed. The frequency and size of fractures were measured and compared with the corresponding histology.

RESULTS

All 15 treated lesions were diagnosed as sheet calcium by histology. Histological evidence of calcium fracture was significantly greater in the IVL group compared with the POBA group (62.5% vs 0.0%; P = 0.01). Calcified lesions with fracture had a larger maximum arc degree of calcification (median 145.6 [IQR: 134.4-300.4] degrees vs 107.0 [IQR: 88.9-129.1] degrees; P = 0.01). Micro-CT and histology showed an excellent correlation for fracture depth (R2 = 0.83; P < 0.0001), whereas OCT showed less correlation (R2 = 0.37; P = 0.11). The depth of fractures measured by OCT were significantly shorter than with those measured by histology (0.49 [IQR: 0.29-0.77] mm vs 0.88 [IQR: 0.64-1.07] mm; P = 0.008).

CONCLUSIONS

IVL demonstrated a histologically superior fracturing effect on coronary calcified lesions compared with POBA. OCT failed to identify the presence of some calcium fractures and underestimated the depth of fracture when compared with micro-CT.

Significance of Intra-plaque Hemorrhage for the Development of High-Risk Vulnerable Plaque: Current Understanding from Basic to Clinical Points of View

Acute coronary syndromes due to atherosclerotic coronary artery disease are a leading cause of morbidity and mortality worldwide. Intra-plaque hemorrhage (IPH), caused by disruption of intra-plaque leaky microvessels, is one of the major contributors of plaque progression, causing a sudden increase in plaque volume and eventually plaque destabilization. IPH and its healing processes are highly complex biological events that involve interactions between multiple types of cells in the plaque, including erythrocyte, macrophages, vascular endothelial cells and vascular smooth muscle cells. Recent investigations have unveiled detailed molecular mechanisms by which IPH leads the development of high-risk "vulnerable" plaque. Current advances in clinical diagnostic imaging modalities, such as magnetic resonance image and intra-coronary optical coherence tomography, increasingly allow us to identify IPH in vivo. To date, retrospective and prospective clinical trials have revealed the significance of IPH as detected by various imaging modalities as a reliable prognostic indicator of high-risk plaque. In this review article, we discuss recent advances in our understanding for the significance of IPH on the development of high-risk plaque from basic to clinical points of view.

Enhanced Thromboresistance and Endothelialization of a Novel Fluoropolymer-Coated Left Atrial Appendage Closure Device

BACKGROUND

Device-related thrombus (DRT) after left atrial appendage closure (LAAC) procedures is a rare but potentially serious event. Thrombogenicity and delayed endothelialization play a role in the development of DRT. Fluorinated polymers are known to have thromboresistant properties that may favorably modulate the healing response to an LAAC device.

OBJECTIVES

The goal of this study was to compare the thrombogenicity and endothelial coverage (EC) after LAAC between the conventional uncoated WATCHMAN FLX (WM) and a novel fluoropolymer-coated WATCHMAN FLX (FP-WM).

METHODS

Canines were randomized for implantation with WM or FP-WM devices and given no postimplant antithrombotic/antiplatelet agents. The presence of DRT was monitored by using transesophageal echocardiography and verified histologically. The biochemical mechanisms associated with coating were assessed by using flow loop experiments to quantify albumin adsorption, platelet adhesion, and porcine implants to quantify EC and the expression of markers of endothelial maturation (ie, vascular endothelial-cadherin/p120-catenin).

RESULTS

Canines implanted with FP-WM exhibited significantly less DRT at 45 days than those implanted with WM (0% vs 50%; P < 0.05). In vitro experiments showed significantly greater albumin adsorption (52.8 [IQR: 41.0-58.3] mm2 vs 20.6 [IQR: 17.2-26.6] mm2; P = 0.03) and significantly less platelet adhesion (44.7% [IQR: 27.2%-60.2%] vs 60.9% [IQR: 39.9%-70.1%]; P < 0.01) on FP-WM. Porcine implants showed significantly greater EC by scanning electron microscopy (87.7% [IQR: 83.4%-92.3%] vs 68.2% [IQR: 47.6%-72.8%]; P = 0.03), and higher vascular endothelial-cadherin/p120-catenin expression after 3 months on FP-WM compared with WM.

CONCLUSIONS

The FP-WM device showed significantly less thrombus and reduced inflammation in a challenging canine model. Mechanistic studies indicated that the fluoropolymer-coated device binds more albumin, leading to reduced platelet binding, less inflammation, and greater EC.

Polygenic Risk Score Associates with Atherosclerotic Plaque Characteristics at Autopsy

Background

Polygenic risk scores (PRS) for coronary artery disease (CAD) potentially improve cardiovascular risk prediction. However, their relationship with histopathologic features of CAD has never been examined systematically.

Methods

From 4,327 subjects referred to CVPath by the State of Maryland Office Chief Medical Examiner (OCME) for sudden death between 1994 and 2015, 2,455 cases were randomly selected for genotyping. We generated PRS from 291 known CAD risk loci. Detailed histopathologic examination of the coronary arteries was performed in all subjects. The primary study outcome measurements were histopathologic plaque features determining severity of atherosclerosis, including %stenosis, calcification, thin-cap fibroatheromas (TCFA), and thrombotic CAD.

Results

After exclusion of cases with insufficient DNA sample quality or with missing data, 954 cases (mean age 48.8±14.7; 75.7% men) remained in the final study cohort. Subjects in the highest PRS quintile exhibited more severe atherosclerosis compared to subjects in the lowest quintile, with greater %stenosis (80.3%±27.0% vs. 50.4%±38.7%; adjusted p<0.001) and a higher frequency of calcification (69.6% vs. 35.8%; adjusted p=0.004) and TCFAs (26.7% vs. 9.5%; adjusted p=0.007). Even after adjustment for traditional CAD risk factors subjects within the highest PRS quintile had higher odds of severe atherosclerosis (i.e., ≥75% stenosis; adjusted OR 3.77; 95%CI 2.10-6.78; p<0.001) and plaque rupture (adjusted OR 4.05; 95%CI 2.26-7.24; p<0.001). Moreover, subjects within the highest quintile had higher odds of CAD-associated cause of death, especially among those aged 50 years and younger (adjusted OR 4.08; 95%CI 2.01-8.30; p<0.001). No associations were observed with plaque erosion.

Conclusions

This is the first autopsy study investigating associations between PRS and atherosclerosis severity at the histopathologic level in subjects with sudden death. Our pathological analysis suggests PRS correlates with plaque burden and features of advanced atherosclerosis and may be useful as a method for CAD risk stratification, especially in younger subjects.

Highlights

In this autopsy study including 954 subjects within the CVPath Sudden Death Registry, high PRS correlated with plaque burden and atherosclerosis severity.The PRS showed differential associations with plaque rupture and plaque erosion, suggesting different etiologies to these two causes of thrombotic CAD.PRS may be useful for risk stratification, particularly in the young. Further examination of individual risk loci and their association with plaque morphology may help understand molecular mechanisms of atherosclerosis, potentially revealing new therapy targets of CAD.

Graphic Abstract

A polygenic risk score, generated from 291 known CAD risk loci, was assessed in 954 subjects within the CVPath Sudden Death Registry. Histopathologic examination of the coronary arteries was performed in all subjects. Subjects in the highest PRS quintile exhibited more severe atherosclerosis as compared to subjects in the lowest quintile, with a greater plaque burden, more calcification, and a higher frequency of plaque rupture.

Local, Downstream, and Systemic Evaluation after Femoral Artery Angioplasty with Kanshas Drug-Coated Balloons In Vitro and in a Healthy Swine Model

PURPOSE

To evaluate the incidence of distal embolism and local vascular responses after treatment with the Kanshas drug-coated balloon (DCB) in a preclinical model.

MATERIALS AND METHODS

A total of 90 femoral arteries from 35 healthy swine were treated with a single-dose (×1) or triple-dose (×3) Kanshas DCB that applies the Unicoat technology with 3.2 μg/mm2 of paclitaxel. An uncoated Kanshas balloon was used as a control. The arterial wall, downstream skeletal muscle, and nontarget organs (kidneys, lungs, lymph nodes, liver, spleen, and heart) were histologically evaluated. For pharmacokinetic evaluation, a total of 40 healthy swine were treated with ×1 Kanshas DCB, and treated vessels were evaluated ex vivo with high-performance liquid chromatography-mass spectrometry.

RESULTS

Arteries treated with the Kanshas DCB showed mild proteoglycan deposition accompanied by the loss of smooth muscle cells (SMCs). These changes increased in a dose-dependent manner (medial SMC loss at 28 days in the ×1 vs ×3 groups, in depth, 1 (0.75-1.38) vs 2 (1.63-2.44); P = .0008; in circumference, 0.83 (0.67-1) vs 1.5 (1.19-1.81); P = .0071). No evidence of distal embolization in skeletal muscles (0 of 210 histological sections) and nontarget organs (0 of 345 sections) was observed. The pharmacokinetic evaluation showed high paclitaxel concentration in the treated artery (912 ng/mg, peaking at 3 minutes), which remained detectable at up to 180 days (0.04 ng/mg).

CONCLUSIONS

The Kanshas DCB showed a local drug effect in treated arteries up to 180 days with a high concentration of paclitaxel and no histological evidence of distal embolization.

Researching COVID to Enhance Recovery (RECOVER) adult study protocol: Rationale, objectives, and design

IMPORTANCE

SARS-CoV-2 infection can result in ongoing, relapsing, or new symptoms or other health effects after the acute phase of infection; termed post-acute sequelae of SARS-CoV-2 infection (PASC), or long COVID. The characteristics, prevalence, trajectory and mechanisms of PASC are ill-defined. The objectives of the Researching COVID to Enhance Recovery (RECOVER) Multi-site Observational Study of PASC in Adults (RECOVER-Adult) are to: (1) characterize PASC prevalence; (2) characterize the symptoms, organ dysfunction, natural history, and distinct phenotypes of PASC; (3) identify demographic, social and clinical risk factors for PASC onset and recovery; and (4) define the biological mechanisms underlying PASC pathogenesis.

METHODS

RECOVER-Adult is a combined prospective/retrospective cohort currently planned to enroll 14,880 adults aged ≥18 years. Eligible participants either must meet WHO criteria for suspected, probable, or confirmed infection; or must have evidence of no prior infection. Recruitment occurs at 86 sites in 33 U.S. states, Washington, DC and Puerto Rico, via facility- and community-based outreach. Participants complete quarterly questionnaires about symptoms, social determinants, vaccination status, and interim SARS-CoV-2 infections. In addition, participants contribute biospecimens and undergo physical and laboratory examinations at approximately 0, 90 and 180 days from infection or negative test date, and yearly thereafter. Some participants undergo additional testing based on specific criteria or random sampling. Patient representatives provide input on all study processes. The primary study outcome is onset of PASC, measured by signs and symptoms. A paradigm for identifying PASC cases will be defined and updated using supervised and unsupervised learning approaches with cross-validation. Logistic regression and proportional hazards regression will be conducted to investigate associations between risk factors, onset, and resolution of PASC symptoms.

DISCUSSION

RECOVER-Adult is the first national, prospective, longitudinal cohort of PASC among US adults. Results of this study are intended to inform public health, spur clinical trials, and expand treatment options.

REGISTRATION

NCT05172024.

Histologic Assessment of Thromboemboli Due to Plaque Rupture, Plaque Erosion, or COVID-19 Microthrombi

Plaque rupture, plaque erosion, and COVID-19 infection can cause acute coronary syndromes (ACS). We illustrate case examples demonstrating the distinctive and characteristic pathologic findings underlying each of these various causes of acute myocardial infarction. A deeper understanding of the pathophysiology of ACS is necessary for the development of newer agents and techniques to improve outcomes after ACS. (Level of Difficulty: Advanced.).

Impaired Reorganization of Centrosome Structure Underlies Human Infantile Dilated Cardiomyopathy

BACKGROUND

During cardiomyocyte maturation, the centrosome, which functions as a microtubule organizing center in cardiomyocytes, undergoes dramatic structural reorganization where its components reorganize from being localized at the centriole to the nuclear envelope. This developmentally programmed process, referred to as centrosome reduction, has been previously associated with cell cycle exit. However, understanding of how this process influences cardiomyocyte cell biology, and whether its disruption results in human cardiac disease, remains unknown. We studied this phenomenon in an infant with a rare case of infantile dilated cardiomyopathy (iDCM) who presented with left ventricular ejection fraction of 18% and disrupted sarcomere and mitochondria structure.

METHODS

We performed an analysis beginning with an infant who presented with a rare case of iDCM. We derived induced pluripotent stem cells from the patient to model iDCM in vitro. We performed whole exome sequencing on the patient and his parents for causal gene analysis. CRISPR/Cas9-mediated gene knockout and correction in vitro were used to confirm whole exome sequencing results. Zebrafish and Drosophila models were used for in vivo validation of the causal gene. Matrigel mattress technology and single-cell RNA sequencing were used to characterize iDCM cardiomyocytes further.

RESULTS

Whole exome sequencing and CRISPR/Cas9 gene knockout/correction identified RTTN, the gene encoding the centrosomal protein RTTN (rotatin), as the causal gene underlying the patient's condition, representing the first time a centrosome defect has been implicated in a nonsyndromic dilated cardiomyopathy. Genetic knockdowns in zebrafish and Drosophila confirmed an evolutionarily conserved requirement of RTTN for cardiac structure and function. Single-cell RNA sequencing of iDCM cardiomyocytes showed impaired maturation of iDCM cardiomyocytes, which underlie the observed cardiomyocyte structural and functional deficits. We also observed persistent localization of the centrosome at the centriole, contrasting with expected programmed perinuclear reorganization, which led to subsequent global microtubule network defects. In addition, we identified a small molecule that restored centrosome reorganization and improved the structure and contractility of iDCM cardiomyocytes.

CONCLUSIONS

This study is the first to demonstrate a case of human disease caused by a defect in centrosome reduction. We also uncovered a novel role for RTTN in perinatal cardiac development and identified a potential therapeutic strategy for centrosome-related iDCM. Future study aimed at identifying variants in centrosome components may uncover additional contributors to human cardiac disease.

Early vascular responses to abluminal biodegradable polymer-coated versus circumferential durable polymer-coated newer-generation drug-eluting stents in humans: a pathological study

BACKGROUND

Recent clinical studies are testing strategies for short (1-3 months) dual antiplatelet therapy following newer-generation drug-eluting stent (DES) placement. However, detailed biological responses to newer-generation DES remain unknown in humans.

AIMS

We sought to evaluate early pathologic responses to abluminal biodegradable polymer-coated (BP-) DES compared with circumferential durable polymer-coated (DP-) DES in human autopsy cases.

METHODS

The study included 38 coronary lesions with newer-generation DES implanted for <90 days (DP-DES=24, BP-DES=14) in 26 autopsy cases. The degree of strut coverage was defined as follows: grade 0 (bare), grade 1 (with fibrin or tissues/cells without endothelium), grade 2 (with single-layered endothelium), and grade 3 (with endothelium and underlying smooth muscle cell layers).

RESULTS

 The duration following implantation was similar in DP- and BP-DES (median=20 vs 17 days). A total of 2,022 struts (DP-DES=1,297, BP-DES=725) were pathologically analysed. Focal grade 2 coverage was observed as early as 5 days after the implantation in both stents. The multilevel mixed-effects ordered logistic regression model demonstrated that BP-DES exhibited greater strut coverage compared with DP-DES (odds ratio [OR]: 3.64, 95% confidence interval [CI]: 1.37-9.67; p=0.009), which remained significant after adjustment for the duration following implantation and underlying tissue characteristics (OR: 2.74, 95% CI: 1.10-6.80; p=0.030). The predictive probability of grade 2 and 3 coverage was comparably limited at 30 days (DP-DES=17.1%, BP-DES=28.7%) and increased at 90 days (DP-DES=76.5%, BP-DES=86.6%). Both stents showed low inflammation and a similar degree of fibrin deposition.

CONCLUSIONS

Single-layered endothelial coverage begins in the days after newer-generation DES placement, and BP-DES potentially exhibit faster strut coverage with smooth muscle cell infiltration than DP-DES in humans. Nevertheless, vessel healing remains suboptimal in both stents at 30 days.

CD163+ macrophages restrain vascular calcification, promoting the development of high-risk plaque

Vascular calcification (VC) is concomitant with atherosclerosis, yet it remains uncertain why rupture-prone high-risk plaques do not typically show extensive calcification. Intraplaque hemorrhage (IPH) deposits erythrocyte-derived cholesterol, enlarging the necrotic core and promoting high-risk plaque development. Pro-atherogenic CD163+ alternative macrophages engulf hemoglobin:haptoglobin (HH) complexes at IPH sites. However, their role in VC has never been examined to our knowledge. Here we show, in human arteries, the distribution of CD163+ macrophages correlated inversely with VC. In vitro experiments using vascular smooth muscle cells (VSMCs) cultured with HH-exposed human macrophage - M(Hb) - supernatant reduced calcification, while arteries from ApoE-/- CD163-/- mice showed greater VC. M(Hb) supernatant-exposed VSMCs showed activated NF-κB, while blocking NF-κB attenuated the anticalcific effect of M(Hb) on VSMCs. CD163+ macrophages altered VC through NF-κB-induced transcription of hyaluronan synthase (HAS), an enzyme that catalyzes the formation of the extracellular matrix glycosaminoglycan, hyaluronan, within VSMCs. M(Hb) supernatants enhanced HAS production in VSMCs, while knocking down HAS attenuated its anticalcific effect. NF-κB blockade in ApoE-/- mice reduced hyaluronan and increased VC. In human arteries, hyaluronan and HAS were increased in areas of CD163+ macrophage presence. Our findings highlight an important mechanism by which CD163+ macrophages inhibit VC through NF-κB-induced HAS augmentation and thus promote the high-risk plaque development.

Intervention with selution SLR™ Agent Balloon for Endovascular Latent Limus therapy for failing AV Fistulas (ISABELLA) Trial: Protocol for a pilot clinical study and pre-clinical results

BACKGROUND

The aim of this pilot clinical study is to evaluate the safety and efficacy of the Selution Sustained Limus Release (SLR)™ sirolimus-coated balloon (M.A. MedAlliance SA, Nyon, Switzerland) for improving the patency of failing arterio-venous fistulas (AVF) in hemodialysis patients. We also present herein a pre-clinical pharmacokinetic and safety evaluation of Selution™ to justify its first use in hemodialysis patients for endovascular access salvage.

METHODS AND RESULTS

This is an investigator-initiated prospective single-center, non-blinded single-arm trial. Forty patients with clinically significant de novo or recurrent stenoses in a mature AVF circuit will be recruited. All stenotic lesions will be prepared with high pressure non-compliant conventional balloon angioplasty (CBA) prior to deployment of the Sustained-Release Selution™ sirolimus drug-eluting balloon. The primary efficacy endpoint is 6-month target lesion primary patency and the primary safety endpoint is freedom from localized or systemic serious adverse events through 30 days. Secondary endpoints of interest include technical and clinical success rates and circuit access patency at 3 and 6 months. Follow-up will occur for 2 years for those patients whose AVFs remain patent. Pharmacokinetic and histological animal safety studies performed with the Selution™ coating formulation showed prolonged arterial tissue retention of sirolimus with therapeutic levels up to 60 days and non-toxic and rapidly declining blood levels. Histological results in animal models demonstrated safety, freedom from intraluminal thrombus, reduction in restenosis by sirolimus elution compared to CBA, and no evidence of embolic phenomena indicative of adverse particulate effects.

DISCUSSION

Long release sirolimus coated balloons may serve as a promising novel alternative therapy to paclitaxel-based technology for treating conduit stenosis secondary to neointimal hyperplasia. Pre-clinical pharmacokinetic and histological animal data are encouraging and provide suggestion of safety and efficacy in this setting. This single-center trial will provide a first step toward demonstration of efficacy and safety of this device for treatment of stenotic fistulas.

Translational value of preclinical models for renal denervation: a histological comparison of human versus porcine renal nerve anatomy

BACKGROUND

Preclinical models have provided key insights into the response of local tissues to radiofrequency (RF) renal denervation (RDN) that is unobtainable from human studies. However, the anatomic translatability of these models to the procedure in humans is incompletely understood.  Aims: We aimed to compare the renal arterial anatomy in normotensive pigs treated with RF-RDN to that of human cadavers to evaluate the suitability of normotensive pigs for determining the safety of RF-RDN.

METHODS

Histopathologic analyses were performed on RF-treated renal arteries in a porcine model and untreated control renal arteries. Similar analyses were performed on untreated renal arteries from human cadavers.  Results: In both human and porcine renal arteries, the median number of nerves was lower in the more distal sections (the numbers in the proximal, middle, distal, 1st bifurcation, and 2nd bifurcation sections were 65, 58, 47, 22.5, and 14.7 in humans, respectively, and 39, 26, 29, 16.5, and 9.3 in the porcine models, respectively). Renal nerves were common in the regions between arteries and adjacent veins, but only 3% and 13% of the renal nerves in humans and pigs, respectively, were located behind the renal vein. The semiquantitative score of RF-induced renal arterial nerve necrosis was significantly greater at 7 days than 28 days (0.98 vs 0.75; p=0.01), and injury to surrounding organs was rarely observed.

CONCLUSIONS

The distribution of nerve tissue and the relative distribution of extravascular anatomic structures along the renal artery was similar between humans and pigs, which validates the translational value of the normotensive porcine model for RDN.

Relationships between neighborhood disadvantage and cardiovascular findings at autopsy in subjects with sudden death

BACKGROUND

Neighborhood disadvantage is associated with a higher risk of sudden cardiac death. However, autopsy findings have never been investigated in this context. Here, we sought to explore associations between neighborhood disadvantage and cardiovascular findings at autopsy in cases of sudden death in the State of Maryland.

METHODS

State of Maryland investigation reports from 2,278 subjects within the CVPath Sudden Death Registry were screened for street addresses and 9-digit zip codes. Area deprivation index (ADI), used as metric for neighborhood disadvantage, was available for 1,464 subjects; 650 of whom self-identified as Black and 814 as White. The primary study outcome measurements were causes of death and gross and histopathologic findings of the heart.

RESULTS

Subjects from most disadvantaged neighborhoods (i.e., ADI ≥ 8; n = 607) died at younger age compared with subjects from less disadvantaged neighborhoods (i.e., ADI ≤ 7; n = 857; 46.07 ± 14.10 vs 47.78 ± 13.86 years; P = 0.02) and were more likely Black or women. They were less likely to die from cardiac causes of death (61.8% vs 67.7%; P = 0.02) and had less severe atherosclerotic plaque features, including plaque burden, calcification, intraplaque hemorrhage, and thin-cap fibroatheromas. In addition, subjects from most disadvantaged neighborhoods had lower frequencies of plaque rupture (18.8% vs 25.1%, P = 0.004). However, these associations were omitted after adjustment for traditional risk factors and race.

CONCLUSION

Neighborhood disadvantage did not associate with cause of death or coronary histopathology after adjustment for cardiovascular risk factors and race, implying that social determinants of health other than neighborhood disadvantage play a more prominent role in sudden cardiac death.

Pulsatile intravascular lithotripsy: A novel mechanism for peripheral artery calcium fragmentation and luminal expansion

OBJECTIVE

To assess the feasibility and treatment effect of pulsatile intravascular lithotripsy (PIVL) on calcified lesions in a cadaveric model of peripheral artery disease.

BACKGROUND

PIVL represents a novel potential approach to intravascular lithotripsy for the treatment of vascular calcification.

METHODS

In this preclinical device-feasibility study, technical success, calcium morphology and luminal expansion before and after PIVL treatment were evaluated in surgically isolated, perfused atherosclerotic lower-leg arteries and in perfused whole cadaveric lower legs. Analytical methods included micro-computed tomography (μCT), intravascular optical coherence tomography, digital subtraction angiography, and quantitative coronary analysis.

RESULTS

Treatment delivery was successful in all whole-leg specimens (N = 6; mean age 74.2, 66 % female) and in the 8 excised vessels with diameter appropriate to the PIVL balloon (2 vessels exceeding diameter specifications were excluded). There were no vessel perforations. After PIVL, excised vessels showed extensive evidence of new, full-thickness fractures in lesions with calcium arc exceeding 152° and with calcium wall thickness between 0.24 mm and 1.42 mm. PIVL fractures were observed in intimal nodules, sheets, shingles, and medial plates. Vessels within whole-leg specimens also showed full-thickness fracturing and a mean of 1.9 ± 0.9 mm in acute luminal gain, 101.6 ± 99.5 % gain in total minimum cross-sectional area, and a 31.7 ± 13.4 % relative reduction in stenosis (P < 0.001 for all analyses).

CONCLUSIONS

In a cadaveric model, PIVL treatment was technically feasible, fractured both circumferential and eccentric calcium lesions, and resulted in acute luminal gain. A clinical feasibility study of PIVL is currently enrolling.

The histological analysis of the coronary medial thickness: Implications for percutaneous coronary intervention

BACKGROUND

A deeper understanding of coronary medial thickness is important for coronary intervention because media thickness can limit the safety and effectiveness of interventional techniques. However, there is a paucity of detailed data on human coronary medial thickness so far.

MATERIALS AND METHODS

We investigated the thickness of the media by histologic analysis. A total of 230 sections from 10 individuals from the CVPath autopsy registry who died from non-coronary deaths were evaluated. We performed pathological analysis on 13 segments of the following primary vessels from coronary arteries: the left main trunk, proximal left anterior descending artery (LAD), mid LAD, distal LAD, proximal left circumflex artery (LCX), mid LCX, distal LCX, proximal right coronary artery (RCA), mid RCA, and the distal RCA. The following side branches were also evaluated: diagonal, obtuse margin, and posterior descending artery branches.

RESULTS

The average age of the studied individuals was 60.4±12.3 years. The median medial thickness for all sections was 0.202 (0.149-0.263) mm. The median medial thickness of the main branches was significantly higher compared to that of the side branches (p<0.001). Although the medial thicknesses of the main branch of LAD and LCX were significantly decreased from proximal to distal segments (p = 0.010, p = 0.006, respectively), the medial thickness of the main branch of RCA was not significantly decreased from proximal to distal (p = 0.170). The thickness of the media was positively correlated with vessel diameter, while it was negatively correlated with luminal narrowing (p<0.001 and p<0.001, respectively).

CONCLUSIONS

The human coronary arteries demonstrate variation in medial thickness which tends to vary depending upon an epicardial coronary artery itself, as well as its segments and branches. Understanding these variations in medial thickness can be useful for both the interventionalists and interventional product development teams.

Transcriptomic-based clustering of human atherosclerotic plaques identifies subgroups with different underlying biology and clinical presentation

Histopathological studies have revealed key processes of atherosclerotic plaque thrombosis. However, the diversity and complexity of lesion types highlight the need for improved sub-phenotyping. Here we analyze the gene expression profiles of 654 advanced human carotid plaques. The unsupervised, transcriptome-driven clustering revealed five dominant plaque types. These plaque phenotypes were associated with clinical presentation and showed differences in cellular compositions. Validation in coronary segments showed that the molecular signature of these plaques was linked to coronary ischemia. One of the plaque types with the most severe clinical symptoms pointed to both inflammatory and fibrotic cell lineages. Further, we did a preliminary analysis of potential circulating biomarkers that mark the different plaques phenotypes. In conclusion, the definition of the plaque at risk for a thrombotic event can be fine-tuned by in-depth transcriptomic-based phenotyping. These differential plaque phenotypes prove clinically relevant for both carotid and coronary artery plaques and point to distinct underlying biology of symptomatic lesions.

Polygenic risk score associates with atherosclerosis severity at autopsy

Background

Polygenic risk scores (PRS) for coronary artery disease (CAD) are emerging as a potential method to improve cardiovascular risk prediction. Questions remain about their applicability to diverse populations as well as their correlation with coronary histopathology.

Purpose

To assess whether high genetic risk associates with histopathologic coronary plaque morphology.

Methods

We assessed 122 known CAD risk loci in 954 Black and White subjects within our sudden death registry to generate a PRS. The cohort was divided into quintiles according to z-score-standardized PRS, both in a race-stratified fashion and in the pooled sample. Detailed histopathologic examination of the coronary arteries was performed in all subjects.

Results

Subjects in the highest PRS quintile exhibited more severe atherosclerosis compared to subjects in the lowest quintile, with greater mean cross-sectional luminal narrowing (71.5% (95% CI, 66.6%-76.5%) vs. 56.6% (95% CI, 51.1%-62.1%); adjusted p&lt;0.001; Figure 1) and a higher frequency of calcification (adjusted OR 2.19; 95% CI 1.31–3.68; p=0.003) after adjustment for the first 10 principal components, age, sex, and race. Higher z-score-standardized PRS was predictive for the finding of severe atherosclerosis (i.e., ≥75% cross-sectional luminal narrowing) even after additional controlling for traditional CAD risk factors including hypertension, smoking, diabetes mellitus, and hyperlipidemia (adjusted OR 1.39; 95% CI 1.19–1.63; p&lt;0.001; Figure 2). Among Black subjects, higher PRS was associated with higher odds of plaque rupture (adjusted OR 1.31; 95% CI 1.03–1.66; p=0.03) and predicted CAD-associated cause of death among subjects younger than 50 years old (adjusted OR 1.26; 95% CI 1.01–1.58; p=0.04).

Conclusions

This is the first autopsy study investigating associations between PRS and atherosclerotic plaque morphology at a histopathologic level. Our pathological analysis suggests PRS correlates with plaque burden and coronary artery calcification and may be useful as a method for CAD risk stratification, especially in younger subjects.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): R01 HL141425 Leducq Foundation Grant

Optical coherence tomography in coronary atherosclerosis assessment and intervention

Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing with the rapid progression of atherosclerosis. Accurate detection by OCT of sequelae from percutaneous coronary interventions that might be missed by angiography could improve clinical outcomes. In addition, OCT has become an essential diagnostic modality for myocardial infarction with non-obstructive coronary arteries. Insight into neoatherosclerosis from OCT could improve our understanding of the mechanisms of very late stent thrombosis. The appropriate use of OCT depends on accurate interpretation and understanding of the clinical significance of OCT findings. In this Review, we summarize the state of the art in cardiac OCT and facilitate the uniform use of this modality in coronary atherosclerosis. Contributions have been made by clinicians and investigators worldwide with extensive experience in OCT, with the aim that this document will serve as a standard reference for future research and clinical application.

In-Stent Restenosis

In-stent restenosis (ISR) remains a potential complication after percutaneous coronary intervention, even in the era of drug-eluting stents, and its treatment remains suboptimal. Neoatherosclerosis is an important component of the pathology of ISR and is accelerated in drug-eluting stents compared with bare-metal stents. Coronary angiography is the gold standard for evaluating the morphology of ISR, although computed tomography angiography is emerging as an alternative noninvasive modality to evaluate the presence of ISR. Drug-coated balloons and stent reimplantation are the current mainstays of treatment for ISR, and the choice of treatment should be based on clinical background and lesion morphology.

Understanding the role of alternative macrophage phenotypes in human atherosclerosis

INTRODUCTION

Atherosclerosis-based ischemic heart disease is still the primary cause of death throughout the world. Over the past decades there has been no significant changes in the therapeutic approaches to atherosclerosis, which are mainly based on lipid lowering therapies and management of comorbid conditions such as diabetes and hypertension. The involvement of macrophages in atherosclerosis has been recognized for decades. More recently, a more detailed and sophisticated understanding of their various phenotypes and roles in the atherosclerotic process has been recognized. This new data is revealing how specific subtypes of macrophage-induced inflammation may have distinct effects on atherosclerosis progression and may provide new approaches for treatment, based upon targeting of specific macrophage subtypes.

AREAS COVERED

We will comprehensively review the spectrum of macrophage phenotypes and how they contribute to atherosclerotic plaque development and progression.

EXPERT OPINION

Various signals derived from atherosclerotic lesions drive macrophages into complex subsets with different gene expression profiles, phenotypes, and functions, not all of which are understood. Macrophage phenotypes include those that enhance, heal, and regress the atherosclerotic lesions though various mechanisms. Targeting of specific macrophage phenotypes may provide a promising and novel approach to prevent atherosclerosis progression.

Monoclonal Autoantibody Against a Cryptic Epitope on Tissue-Adherent Low-Density Lipoprotein for Molecular Imaging in Atherosclerosis

BACKGROUND

Antibody-based constructs for molecular imaging and therapeutic delivery provide promising opportunities for the diagnosis and treatment of atherosclerosis.

OBJECTIVES

The authors aimed to generate and characterize immunoglobulin (Ig)G monoclonal autoantibodies in atherosclerosis for targeting of novel molecular determinants.

METHODS

The authors created hybridomas from an unimmunized low-density lipoprotein (LDL) receptor-deficient (Ldlr-/-) mouse and selected an IgG2b isotype autoantibody, LO9, for further characterization.

RESULTS

LO9 reacted well with native LDL bound to immobilized matrix components and less well to oxidized LDL. LO9 binding to immobilized native LDL was not neutralized by fluid-phase native LDL, indicating an adhesion-dependent epitope. The authors localized the epitope to a 20 amino-acid peptide sequence (P5) in the globular amino-terminus of apolipoprotein B. LO9 reacted with antigen in mouse atherosclerosis and in both human stable and ruptured coronary atherosclerosis. Furthermore, in vivo near-infrared fluorescence molecular tomographic imaging, and ex vivo confocal microscopy showed that intravenously injected LO9 localized beneath endothelium of the aortic arch in Ldlr-/- mice, in the vicinity of macrophages.

CONCLUSIONS

The authors believe LO9 is the first example of an IgG autoantibody that reacts with a native LDL epitope revealed by adherence to tissue matrix. Antibodies against adherent native LDL have potential as molecular targeting agents for imaging of and therapeutic delivery to atherosclerosis.

Opportunities and Challenges in Understanding Atherosclerosis by Human Biospecimen Studies

Over the last few years, new high-throughput biotechnologies and bioinformatic methods are revolutionizing our way of deep profiling tissue specimens at the molecular levels. These recent innovations provide opportunities to advance our understanding of atherosclerosis using human lesions aborted during autopsies and cardiac surgeries. Studies on human lesions have been focusing on understanding the relationship between molecules in the lesions with tissue morphology, genetic risk of atherosclerosis, and future adverse cardiovascular events. This review will highlight ways to utilize human atherosclerotic lesions in translational research by work from large cardiovascular biobanks to tissue registries. We will also discuss the opportunities and challenges of working with human atherosclerotic lesions in the era of next-generation sequencing.

Generalized Arterial Calcification of Infancy (GACI): Optimizing Care with a Multidisciplinary Approach

It is very unusual to see evidence of arterial calcification in infants and children, and when detected, genetic disorders of calcium metabolism should be suspected. Generalized arterial calcification of infancy (GACI) is a hereditary disease, which is characterized by severe arterial calcification of medium sized arteries, mostly involving the media with marked intimal proliferation and ectopic mineralization of the extravascular tissues. It is caused by inactivating variants in genes encoding either ENPP1, in a majority of cases (70–75%), or ABCC6, in a minority (9–10%). Despite similar histologic appearances between ENPP1 and ABCC6 deficiencies, including arterial calcification, organ calcification, and cardiovascular calcification, mortality is higher in subjects carrying the ENPP1 versus ABCC6 variants (40% vs 10%, respectively). Overall mortality in individuals with GACI is high (55%) before the age of 6 months, with 24.4% dying in utero or being stillborn. Rare cases show spontaneous regression with age, while others who survive into adulthood often manifest musculoskeletal complications (osteoarthritis and interosseous membrane ossification), enthesis mineralization, and cervical spine fusion. Despite recent advances in the understanding of the genetic mechanisms underlying this disease, there is still no ideal therapy for the resolution of vascular calcification in GACI. Although bisphosphonates with anti-calcification properties have been commonly used for the treatment of CAGI, their benefit is controversial, with favorable results reported at one year and questionable benefit with delayed initiation of treatment. Enzyme replacement therapy with administration of recombinant form of ENPP1 prevents calcification and mortality, improves hypertension and cardiac function, and prevents intimal proliferation and osteomalacia in mouse models of ENPP1 deficiency. Therefore, newer treatments targeting genes are on the horizon. In this article, we review up to date knowledge of the understanding of GACI, its clinical, pathologic, and etiologic understanding and treatment in support of more comprehensive care of GACI patients.

Single-nucleus chromatin accessibility profiling highlights regulatory mechanisms of coronary artery disease risk

Coronary artery disease (CAD) is a complex inflammatory disease involving genetic influences across cell types. Genome-wide association studies (GWAS) have identified over 200 loci associated with CAD, where the majority of risk variants reside in noncoding DNA sequences impacting cis-regulatory elements (CREs). Here, we applied single-nucleus ATAC-seq to profile 28,316 nuclei across coronary artery segments from 41 patients with varying stages of CAD, which revealed 14 distinct cellular clusters. We mapped ~320,000 accessible sites across all cells, identified cell type-specific elements, transcription factors, and prioritized functional CAD risk variants. . We identified elements in smooth muscle cell (SMC) transition states (e.g. fibromyocytes) and functional variants predicted to alter SMC and macrophage-specific regulation of MRAS (3q22) and LIPA (10q23), respectively. We further nominated key driver transcription factors such as PRDM16 and TBX2. Together, this single nucleus atlas provides a critical step towards interpreting regulatory mechanisms across the continuum of CAD risk.

Clinical Trial Design Principles and Outcomes Definitions for Device-Based Therapies for Hypertension: A Consensus Document From the Hypertension Academic Research Consortium

The clinical implications of hypertension in addition to a high prevalence of both uncontrolled blood pressure and medication nonadherence promote interest in developing device-based approaches to hypertension treatment. The expansion of device-based therapies and ongoing clinical trials underscores the need for consistency in trial design, conduct, and definitions of clinical study elements to permit trial comparability and data poolability. Standardizing methods of blood pressure assessment, effectiveness measures beyond blood pressure alone, and safety outcomes are paramount. The Hypertension Academic Research Consortium (HARC) document represents an integration of evolving evidence and consensus opinion among leading experts in cardiovascular medicine and hypertension research with regulatory perspectives on clinical trial design and methodology. The HARC document integrates the collective information among device-based therapies for hypertension to better address existing challenges and identify unmet needs for technologies proposed to treat the world’s leading cause of death and disability. Consistent with the Academic Research Consortium charter, this document proposes pragmatic consensus clinical design principles and outcomes definitions for studies aimed at evaluating device-based hypertension therapies.