RNAseq profiling of blood from patients with coronary artery disease: Signature of a T cell imbalance.

Background: Cardiovascular disease had a global prevalence of 523 million cases and 18.6 million deaths in 2019. The current standard for diagnosing coronary artery disease (CAD) is coronary angiography either by invasive catheterization (ICA) or computed tomography (CTA). Prior studies employed single-molecule, amplification-independent RNA sequencing of whole blood to identify an RNA signature in patients with angiographically confirmed CAD. The present studies employed Illumina RNAseq and network co-expression analysis to identify systematic changes underlying CAD. Methods: Whole blood RNA was depleted of ribosomal RNA (rRNA) and analyzed by Illumina total RNA sequencing (RNAseq) to identify transcripts associated with CAD in 177 patients presenting for elective invasive coronary catheterization. The resulting transcript counts were compared between groups to identify differentially expressed genes (DEGs) and to identify patterns of changes through whole genome co-expression network analysis (WGCNA). Results: The correlation between Illumina amplified RNAseq and the prior SeqLL unamplified RNAseq was quite strong (r = 0.87), but there was only 9 % overlap in the DEGs identified. Consistent with the prior RNAseq, the majority (93 %) of DEGs were down-regulated ~1.7-fold in patients with moderate to severe CAD (>20 % stenosis). DEGs were predominantly related to T cells, consistent with known reductions in Tregs in CAD. Network analysis did not identify pre-existing modules with a strong association with CAD, but patterns of T cell dysregulation were evident. DEGs were enriched for transcripts associated with ciliary and synaptic transcripts, consistent with changes in the immune synapse of developing T cells. Conclusions: These studies confirm and extend a novel mRNA signature of a Treg-like defect in CAD. The pattern of changes is consistent with stress-related changes in the maturation of T and Treg cells, possibly due to changes in the immune synapse.

Direct Comparison of Outcomes After Transcatheter Aortic Valve Replacement in Veterans and Non-Veterans Using the Transcatheter Valve Therapy Registry.

OBJECTIVES: This study aims to compare veterans and non-veterans undergoing transcatheter aortic valve replacement (TAVR) using data from the Society for Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy (STS/ACC TVT) registry. METHODS: Patients undergoing TAVR at George Washington University (GWU) and veterans treated at Washington DC Veterans Affairs Medical Center (VAMC) who underwent TAVR at GWU from 2014-2020 were included. All patients were reported in the TVT registry. Emergency and valve-in-valve TAVR were excluded. Cohorts were divided based on veteran status. Operators were the same for both groups. Outcomes were compared at 30 days and 1 year. The primary outcome was mortality and secondary outcomes were morbidity metrics. RESULTS: A total of 299 patients (91 veterans, 208 non-veterans) were included. Veterans had higher rates of hypertension (87.9% vs 77.9%; P=.04), diabetes (46.7% vs 28.9%; P<.01), and lung disease (2.4% vs 11.0%; P<.001). Outcomes were not significantly different between veterans and non-veterans, including 30-day mortality (0% vs 2.9%, respectively; P=.18), 1-year mortality (9.8% vs 10.7%, respectively; P=.61), stroke incidence (0% vs 2.5%, respectively; P=.73), median intensive care unit stay (24 hours in both groups), and overall hospital stay (2 days in both groups). CONCLUSIONS: The affiliation between a VAMC and an academic medical center allowed for direct comparison between veterans and non-veterans undergoing TAVR by the same operators using the TVT registry. Despite significantly higher rates of comorbidities, veterans had equivalent outcomes compared with non-veterans. This may be in part due to the comprehensive care that veterans receive in the VAMC and this institution's integrated heart center team.

RNA sequencing of blood in coronary artery disease: involvement of regulatory T cell imbalance.

BACKGROUND: Cardiovascular disease had a global prevalence of 523 million cases and 18.6 million deaths in 2019. The current standard for diagnosing coronary artery disease (CAD) is coronary angiography. Surprisingly, despite well-established clinical indications, up to 40% of the one million invasive cardiac catheterizations return a result of 'no blockage'. The present studies employed RNA sequencing of whole blood to identify an RNA signature in patients with angiographically confirmed CAD. METHODS: Whole blood RNA was depleted of ribosomal RNA (rRNA) and analyzed by single-molecule sequencing of RNA (RNAseq) to identify transcripts associated with CAD (TRACs) in a discovery group of 96 patients presenting for elective coronary catheterization. The resulting transcript counts were compared between groups to identify differentially expressed genes (DEGs). RESULTS: Surprisingly, 98% of DEGs/TRACs were down-regulated ~ 1.7-fold in patients with mild to severe CAD (> 20% stenosis). The TRACs were independent of comorbid risk factors for CAD, such as sex, hypertension, and smoking. Bioinformatic analysis identified an enrichment in transcripts such as FoxP1, ICOSLG, IKZF4/Eos, SMYD3, TRIM28, and TCF3/E2A that are likely markers of regulatory T cells (Treg), consistent with known reductions in Tregs in CAD. A validation cohort of 80 patients confirmed the overall pattern (92% down-regulation) and supported many of the Treg-related changes. TRACs were enriched for transcripts associated with stress granules, which sequester RNAs, and ciliary and synaptic transcripts, possibly consistent with changes in the immune synapse of developing T cells. CONCLUSIONS: These studies identify a novel mRNA signature of a Treg-like defect in CAD patients and provides a blueprint for a diagnostic test for CAD. The pattern of changes is consistent with stress-related changes in the maturation of T and Treg cells, possibly due to changes in the immune synapse.

Cardiovascular Disease Risk Factors and Myocardial Infarction in the Transgender Population.

BACKGROUND: As of 2016, ≈1.4 million people in the United States identify as transgender. Despite their growing number and increasing specific medical needs, there has been a lack of research on cardiovascular disease (CVD) and CVD risk factors in this population. Recent studies have reported that the transgender population had a significantly higher rate of CVD risk factors without a significant increase in overall CVD morbidity and mortality. These studies are limited by their small sample sizes and their predominant focus on younger transgender populations. With a larger sample size and inclusion of broader age range, our study aims to provide insight into the association between being transgender and cardiovascular risk factors, as well as myocardial infarction. METHODS AND RESULTS: The Behavioral Risk Factor Surveillance System data from 2014 to 2017 were used to evaluate the cross-sectional association between being transgender and the reported history of myocardial infarction and CVD risk factors. A logistic regression model was constructed to study the association between being transgender and myocardial infarction after adjusting for CVD risk factors including age, diabetes mellitus, hypertension, hypercholesterolemia, chronic kidney disease, smoking, and exercise. Multivariable analysis revealed that transgender men had a >2-fold and 4-fold increase in the rate of myocardial infarction compared with cisgender men (odds ratio, 2.53; 95% CI, 1.14-5.63; P=0.02) and cisgender women (odds ratio, 4.90; 95% CI, 2.21-10.90; P<0.01), respectively. Conversely, transgender women had >2-fold increase in the rate of myocardial infarction compared with cisgender women (odds ratio, 2.56; 95% CI, 1.78-3.68; P<0.01) but did not have a significant increase in the rate of myocardial infarction compared with cisgender men. CONCLUSIONS: The transgender population had a higher reported history of myocardial infarction in comparison to the cisgender population, except for transgender women compared with cisgender men, even after adjusting for cardiovascular risk factors.

Outcomes of Acute Conduction Abnormalities Following Transcatheter Aortic Valve Implantation With a Balloon Expandable Valve and Predictors of Delayed Conduction System Abnormalities in Follow-up.

Transcatheter aortic valve implantation (TAVI) is an acceptable treatment for severe aortic stenosis in high or intermediate risk patients. Conduction abnormalities are a known complication of TAVI. Most abnormalities occur perioperatively but can develop later. The predictors of delayed conduction abnormalities are unknown. Patients who underwent TAVI at our institution were reviewed. Patients with a pre-existing pacemaker were excluded. Baseline, in-hospital, and 30-day follow-up ECGs were reviewed. Patient and procedural characteristics were analyzed to look for predictors of acute and delayed abnormalities. Ninety-eight patients were included. All valves implanted were balloon expandable, most commonly SAPIEN S3 (78%). Thirty-seven (37.7%) patients developed abnormalities before discharge. Of these patients, 20 (57.1%) had complete resolution at 30-day follow-up. No patients with new conduction abnormalities during hospitalization had additional abnormalities at 30-day follow-up. Five (5.1%) patients developed new conduction abnormalities following discharge. Overall, 22 (22.4%) patients had conduction abnormalities at 30-day follow-up which were not present at baseline. Predilatation (p = 0.003), higher ratios of balloon (p = 0.03) or valve (p = 0.05) size to left ventricular outflow tract, and previous myocardial infarction (p = 0.034) were predictive of acute conduction abnormalities. Baseline right bundle branch block (p = 0.002), longer baseline (p <0.001) and discharge (p = 0.004) QRS duration, moderate, or severe aortic insufficiency (p = 0.002) and atrial fibrillation (p = 0.031) were predictors of new conduction abnormalities after discharge. In conclusion, most new in-hospital conduction abnormalities resolve by 30-day follow-up. In-hospital conduction abnormalities are related to technical aspects of TAVI while delayed conduction abnormalities are related to baseline conduction system disease.

Percutaneous management of ostial stenosis of the left internal mammary artery graft.

A 61-year-old man, who had undergone coronary artery bypass surgery 10 years earlier, presented with a non-ST segment elevation myocardial infarction. He was treated with medical therapy and taken to the Cardiac Catheterization Laboratory. A left heart catheterization demonstrated an ostial stenosis in the left internal mammary artery graft, which was felt to be the culprit lesion. This was successfully repaired with a drug eluting stent. This case is presented as an unusual location for a de novo coronary stenosis. The pathophysiology of these lesions is not well understood.

Seeing the Invisible: Revealing Atrial Ablation Lesions Using Hyperspectral Imaging Approach.

BACKGROUND: Currently, there are limited means for high-resolution monitoring of tissue injury during radiofrequency ablation procedures. OBJECTIVE: To develop the next generation of visualization catheters that can reveal irreversible atrial muscle damage caused by ablation and identify viability gaps between the lesions. METHODS: Radiofrequency lesions were placed on the endocardial surfaces of excised human and bovine atria and left ventricles of blood perfused rat hearts. Tissue was illuminated with 365nm light and a series of images were acquired from individual spectral bands within 420-720nm range. By extracting spectral profiles of individual pixels and spectral unmixing, the relative contribution of ablated and unablated spectra to each pixel was then displayed. Results of spectral unmixing were compared to lesion pathology. RESULTS: RF ablation caused significant changes in the tissue autofluorescence profile. The magnitude of these spectral changes in human left atrium was relatively small (< 10% of peak fluorescence value), yet highly significant. Spectral unmixing of hyperspectral datasets enabled high spatial resolution, in-situ delineation of radiofrequency lesion boundaries without the need for exogenous markers. Lesion dimensions derived from hyperspectral imaging approach strongly correlated with histological outcomes. Presence of blood within the myocardium decreased the amplitude of the autofluorescence spectra while having minimal effect on their overall shapes. As a result, the ability of hyperspectral imaging to delineate ablation lesions in vivo was not affected. CONCLUSIONS: Hyperspectral imaging greatly increases the contrast between ablated and unablated tissue enabling visualization of viability gaps at clinically relevant locations. Data supports the possibility for developing percutaneous hyperspectral catheters for high-resolution ablation guidance.

Estimation of cardiac output and pulmonary vascular resistance by contrast echocardiography transit time measurement: a prospective pilot study.

BACKGROUND: Studies with other imaging modalities have demonstrated a relationship between contrast transit and cardiac output (CO) and pulmonary vascular resistance (PVR). We tested the hypothesis that the transit time during contrast echocardiography could accurately estimate both CO and PVR compared to right heart catheterization (RHC). METHODS: 27 patients scheduled for RHC had 2D-echocardiogram immediately prior to RHC. 3 ml of DEFINITY contrast followed by a 10 ml saline flush was injected, and a multi-cycle echo clip was acquired from the beginning of injection to opacification of the left ventricle. 2D-echo based calculations of CO and PVR along with the DEFINITY-based transit time calculations were subsequently correlated with the RHC-determined CO and PVR. RESULTS: The transit time from full opacification of the right ventricle to full opacification of the left ventricle inversely correlated with CO (r=-0.61, p<0.001). The transit time from peak opacification of the right ventricle to first appearance in the left ventricle moderately correlated with PVR (r=0.46, p<0.01). Previously described echocardiographic methods for the determination of CO (Huntsman method) and PVR (Abbas and Haddad methods) did not correlate with RHC-determined values (p = 0.20 for CO, p = 0.18 and p = 0.22 for PVR, respectively). The contrast transit time method demonstrated reliable intra- (p<0.0001) and inter-observer correlation (p<0.001). CONCLUSIONS: We describe a novel method for the quantification of CO and estimation of PVR using contrast echocardiography transit time. This technique adds to the methodologies used for noninvasive hemodynamic assessment, but requires further validation to determine overall applicability.

Translational findings from cardiovascular stem cell research.

The possibility of using stem cells to regenerate damaged myocardium has been actively investigated since the late 1990s. Consistent with the traditional view that the heart is a "postmitotic" organ that possesses minimal capacity for self-repair, much of the preclinical and clinical work has focused exclusively on introducing stem cells into the heart, with the hope of differentiation of these cells into functioning cardiomyocytes. This approach is ongoing and retains promise but to date has yielded inconsistent successes. More recently, it has become widely appreciated that the heart possesses endogenous repair mechanisms that, if adequately stimulated, might regenerate damaged cardiac tissue from in situ cardiac stem cells. Accordingly, much recent work has focused on engaging and enhancing endogenous cardiac repair mechanisms. This article reviews the literature on stem cell-based myocardial regeneration, placing emphasis on the mutually enriching interaction between basic and clinical research.

Multimodality imaging to diagnose pulmonary vein stenosis following atrial fibrillation ablation.

BACKGROUND: Atrial fibrillation (AF) is increasing in prevalence. Although experienced centers performing radiofrequency pulmonary vein isolation procedures have reported success rates approaching 72%, in rare instances it is complicated by stenosis of one or more pulmonary veins. In this report we present a case of recurrent pulmonary vein stenosis (PVS) following radiofrequency ablation for AF.

Positron emission tomography for the evaluation and treatment of cardiomyopathy.

Congestive heart failure accounts for tremendous morbidity and mortality worldwide. There are numerous causes of cardiomyopathy, the most common of which is coronary artery disease. Positron emission tomography (PET) has an established and expanding role in the evaluation of patients with cardiomyopathy. The specific application of PET to hypertrophic cardiomyopathy, cardiac sarcoidosis, and diabetic cardiomyopathy has been studied extensively and promises to be a useful tool for managing these patients. Furthermore, evaluating the efficacy of standard treatments for congestive heart failure is important as health care costs continue to rise. Recently, there have been significant developments in the field of cardiovascular stem cell research. Familiarity with the mechanisms by which stem cells benefit patients with cardiovascular disease is the key to understanding these advances. Molecular imaging techniques including PET/CT imaging play an important role in monitoring stem cell therapy in both animals and humans. These noninvasive imaging techniques will be highlighted in this paper.

Bone marrow mesenchymal stem cells stimulate cardiac stem cell proliferation and differentiation.

RATIONALE: The regenerative potential of the heart is insufficient to fully restore functioning myocardium after injury, motivating the quest for a cell-based replacement strategy. Bone marrow-derived mesenchymal stem cells (MSCs) have the capacity for cardiac repair that appears to exceed their capacity for differentiation into cardiac myocytes. OBJECTIVE: Here, we test the hypothesis that bone marrow derived MSCs stimulate the proliferation and differentiation of endogenous cardiac stem cells (CSCs) as part of their regenerative repertoire. METHODS AND RESULTS: Female Yorkshire pigs (n=31) underwent experimental myocardial infarction (MI), and 3 days later, received transendocardial injections of allogeneic male bone marrow-derived MSCs, MSC concentrated conditioned medium (CCM), or placebo (Plasmalyte). A no-injection control group was also studied. MSCs engrafted and differentiated into cardiomyocytes and vascular structures. In addition, endogenous c-kit(+) CSCs increased 20-fold in MSC-treated animals versus controls (P<0.001), there was a 6-fold increase in GATA-4(+) CSCs in MSC versus control (P<0.001), and mitotic myocytes increased 4-fold (P=0.005). Porcine endomyocardial biopsies were harvested and plated as organotypic cultures in the presence or absence of MSC feeder layers. In vitro, MSCs stimulated c-kit(+) CSCs proliferation into enriched populations of adult cardioblasts that expressed Nkx2-5 and troponin I. CONCLUSIONS: MSCs stimulate host CSCs, a new mechanism of action underlying successful cell-based therapeutics.

Quantitative automated assessment of myocardial perfusion at cardiac catheterization.

Perfusion assessed in the cardiac catheterization laboratory predicts outcomes after myocardial infarction. The aim of this study was to investigate a novel method of assessing perfusion using digital subtraction angiography to generate a time-density curve (TDC) of myocardial blush, incorporating epicardial and myocardial perfusion. Seven pigs underwent temporary occlusion of the left anterior descending coronary artery for 60 minutes. Angiography was performed in the same projections before, during, and after occlusion. Perfusion parameters were obtained from the TDC and compared with Thrombolysis In Myocardial Infarction (TIMI) frame count and myocardial perfusion grade. In addition, safety and feasibility were tested in 8 patients after primary percutaneous coronary intervention. The contrast density differential between the proximal artery and the myocardium derived from the TDC correlated well with TIMI myocardial perfusion grade (R = 0.54, p <0.001). The arterial transit time derived from the TDC correlated with TIMI frame count (R = 0.435, p = 0.011). Using a cutoff of 2.4, the density/time ratio, a ratio of density differential to transit time, had sensitivity and specificity of 100% for coronary arterial occlusion. The positive and negative predictive values were 100%. The generation of a TDC was safe and feasible in 7 patients after acute myocardial infarctions, but the correlation between TDC-derived parameters and TIMI parameters did not reach statistical significance. In conclusion, this novel method of digital subtraction angiography with rapid, automated, quantitative assessment of myocardial perfusion in the cardiac catheterization laboratory correlates well with established angiographic measures of perfusion. Further studies to assess the prognostic value of this technique are warranted.

Advances in cell-based therapy for structural heart disease.

Congestive heart failure and coronary artery disease are the leading causes of morbidity and mortality in the United States despite substantial therapeutic advances in the last half century. Only very recently have studies arisen that support possibility of regenerating tissue of damaged human organs including the heart. In this regard, there is growing pre-clinical and clinical evidence demonstrating the safety and efficacy of cell-based myocardial regeneration using a variety of cell lines. Although the data on the exact mechanism of action and the fate of the administered cells is controversial, there is consistent evidence for improved cardiac function and myocardial regeneration using different cell types. This extraordinarily exciting scientific advance has forced cardiovascular scientists to re-evaluate the long-held paradigm of cardiac myocyte terminal differentiation and life-long longevity of the cardiac myocytes that comprise the heart. Whereas, these new ideas originated with attempts to perform cellular transplantation using exogenous stem or precursor cells, mechanistic insights have rapidly evolved to the realization that adult organs harbor stem cells with significant plasticity, capable of repopulating their respective organ. Indeed these cells may be harnessed as a therapeutic agent or may represent the target of regenerative therapeutic strategies.

Mechanisms of action of mesenchymal stem cells in cardiac repair: potential influences on the cardiac stem cell niche.

Clinical and basic studies of cell-based myocardial therapy have proceeded at a rapid pace. Cell therapy could lead to successful cardiac regeneration or repair by any of three general mechanisms: differentiation of the administered cells into all of the cellular constituents of the heart; release of factors capable of paracrine signaling from the administered cells; and fusion of the administered cells with the existing constituents of the heart. Here, we argue that a fourth general mechanism could be operative: stimulation of endogenous repair by injected cells, which and might cause the regeneration of stem cell niches. In a porcine model of myocardial infarction, allogeneic mesenchymal stem cells stimulated substantial improvement in the ejection fraction, reduction of infarct size, and the growth of a rim of new cardiac tissue in the region in which the mesenchymal stem cells were injected. These effects occurred in the absence of definitive cardiac myocyte differentiation. After myocardial infarction, porcine hearts exhibit evidence of cardiac myocytes that have entered the cell cycle, neovascularization, and reduced levels of apoptosis. These data, in addition to new insights regarding the presence of endogenous cardiac stem cells, strongly support the concept that the heart could contain stem cell niches. Effective cell therapy could lead to restoration of these niches through multifaceted cell-cell interactions.

Aging impairs the beneficial effect of granulocyte colony-stimulating factor and stem cell factor on post-myocardial infarction remodeling.

Granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) are potential new therapies to ameliorate post-myocardial infarction (post-MI) remodeling, as they enhance endogenous cardiac repair mechanisms and decrease cardiomyocyte apoptosis. Because both of these pathways undergo alterations with increasing age, we hypothesized that therapeutic efficacy of G-CSF and SCF is impaired in old versus young adult rats. MI was induced in 6- and 20-month-old rats by permanent ligation of the left coronary artery. In young animals, G-CSF/SCF therapy stabilized and reversed a decline in cardiac function, attenuated left ventricular dilation, decreased infarct size, and reduced cardiomyocyte hypertrophy. Remarkably, these effects on cardiac structure and function were absent in aged rodents. This could not be attributed to ineffective mobilization of bone marrow cells or decreased quantity of c-Kit(+) cells within the myocardium with aging. However, whereas the G-CSF/SCF cocktail reduced cardiac myocyte apoptosis in old as well as in young hearts, the degree of reduction was substantially less with age and the rate of cardiomyocyte apoptosis in old animals remained high despite cytokine treatment. These findings demonstrate that G-CSF/SCF lacks therapeutic efficacy in old animals by failing to offset periinfarct apoptosis and therefore raise important concerns regarding the efficacy of novel cytokine therapies in elderly individuals at greatest risk for adverse consequences of MI.

Prevalence, clinical significance, and management of peripheral arterial disease in women: is there a role for postmenopausal hormone therapy?

Peripheral arterial disease (PAD), like coronary heart disease, is a clinical manifestation of atherosclerosis and is associated with increased mortality. Although atherosclerotic cardiovascular disease is the leading cause of death for women as well as for men, PAD in women has received less attention than coronary heart disease or stroke. This paper reviews the prevalence of PAD, its risk factors, clinical significance, and management in women. One gender-specific therapeutic issue of particular interest to practitioners and the lay public is the role of postmenopausal hormone therapy. Prior to completion of the Heart and Estrogen/Progestin Replacement Study and the Women's Health Initiative Hormone Trials, postmenopausal hormone therapy was believed to exert antiatherosclerotic effects and to thereby reduce coronary heart disease risk in women on the basis of case-control and cohort studies. This review particularly focuses on the role, if any, of postmenopausal hormone therapy for prevention or treatment of PAD, which was a pre-specified secondary outcome for these three randomized trials.

Hematuria: an algorithmic approach to finding the cause.

Many conditions can cause hematuria, but the differential diagnosis can be simplified with a systematic approach. We discuss the common causes of hematuria and how to evaluate it.