Genetic testing in cardiovascular disease.

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally and is responsible for an estimated one-third of deaths as well as significant morbidity and health care utilisation. Technological and bioinformatic advances have facilitated the discovery of pathogenic germline variants for some specific CVDs, including familial hypercholesterolaemia, cardiomyopathies and arrhythmic syndromes. Use of these genetic tests for earlier disease identification is increasing due, in part, to decreasing costs, Medicare rebates, and consumer comfort with genetic testing. However, CVDs that occur more commonly, including coronary artery disease and atrial fibrillation, do not display monogenic inheritance patterns. Genetically, these diseases have generally been associated with many genetic variants each with a small effect size. This complexity can be expressed mathematically as a polygenic risk score. Genetic testing kits that provide polygenic risk scoring are becoming increasingly available directly to private-paying consumers outside the traditional clinical setting. An improved understanding of the evidence of genetics in CVD will offer clinicians new opportunities for individualised risk prediction and preventive therapy.

Incorporating a polygenic risk score-triaged coronary calcium score into cardiovascular disease examinations to identify subclinical coronary artery disease (ESCALATE): Protocol for a prospective, nonrandomized implementation trial.

BACKGROUND: Identifying and targeting established modifiable risk factors has been a successful strategy for reducing the burden of coronary artery disease (CAD) at the population-level. However, up to 1-in-4 patients who present with ST elevation myocardial infarction do so in the absence of such risk factors. Polygenic risk scores (PRS) have demonstrated an ability to improve risk prediction models independent of traditional risk factors and self-reported family history, but a pathway for implementation has yet to be clearly identified. The aim of this study is to examine the utility of a CAD PRS to identify individuals with subclinical CAD via a novel clinical pathway, triaging low or intermediate absolute risk individuals for noninvasive coronary imaging, and examining the impact on shared treatment decisions and participant experience. TRIAL DESIGN: The ESCALATE study is a 12-month, prospective, multicenter implementation study incorporating PRS into otherwise standard primary care CVD risk assessments, to identify patients at increased lifetime CAD risk for noninvasive coronary imaging. One-thousand eligible participants aged 45 to 65 years old will enter the study, which applies PRS to those considered low or moderate 5-year absolute CVD risk and triages those with CAD PRS ≥80% for a coronary calcium scan. The primary outcome will be the identification of subclinical CAD, defined as a coronary artery calcium score (CACS) >0 Agatston units (AU). Multiple secondary outcomes will be assessed, including baseline CACS ≥100 AU or ≥75th age-/sex-matched percentile, the use and intensity of lipid- and blood pressure-lowering therapeutics, cholesterol and blood pressure levels, and health-related quality of life (HRQOL). CONCLUSION: This novel trial will generate evidence on the ability of a PRS-triaged CACS to identify subclinical CAD, as well as subsequent differences in traditional risk factor medical management, pharmacotherapy utilization, and participant experience. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, ACTRN12622000436774. Trial was prospectively registered on March 18, 2022. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=383134.

High-Throughput Measure of Mitochondrial Superoxide Levels as a Marker of Coronary Artery Disease to Accelerate Drug Translation in Patient-Derived Endothelial Cells Using Opera Phenix® Technology.

Improved human-relevant preclinical models of coronary artery disease (CAD) are needed to improve translational research and drug discovery. Mitochondrial dysfunction and associated oxidative stress contribute to endothelial dysfunction and are a significant factor in the development and progression of CAD. Endothelial colony-forming cells (ECFCs) can be derived from peripheral blood mononuclear cells (PBMCs) and offer a unique potentially personalised means for investigating new potential therapies targeting important components of vascular function. We describe the application of the high-throughput and confocal Opera Phenix® High-Content Screening System to examine mitochondrial superoxide (mROS) levels, mitochondrial membrane potential, and mitochondrial area in both established cell lines and patient-derived ECFCs simultaneously. Unlike traditional plate readers, the Opera Phenix® is an imaging system that integrates automated confocal microscopy, precise fluorescent detection, and multi-parameter algorithms to visualize and precisely quantify targeted biological processes at a cellular level. In this study, we measured mROS production in human umbilical vein endothelial cells (HUVECs) and patient-derived ECFCs using the mROS production probe, MitoSOXTM Red. HUVECs exposed to oxidized low-density lipoprotein (oxLDL) increased mROS levels by 47.7% (p < 0.0001). A pooled group of patient-derived ECFCs from participants with CAD (n = 14) exhibited 30.9% higher mROS levels compared to patients with no CAD when stimulated with oxLDL (n = 14; p < 0.05). When tested against a small group of candidate compounds, this signal was attenuated by PKT-100 (36.22% reduction, p = 0.03), a novel P2X7 receptor antagonist. This suggests the P2X7 receptor as a valid target against excess mROS levels. As such, these findings highlight the potential of the MitoSOX-Opera Phenix technique to be used for drug discovery efforts in CAD.

EmPHasis-10 as a measure of health-related quality of life in pulmonary arterial hypertension: data from PHAR.

INTRODUCTION: While the performance of the emPHasis-10 (e10) score has been evaluated against limited patient characteristics within the United Kingdom, there is an unmet need for exploring the performance of the e10 score among pulmonary arterial hypertension (PAH) patients in the United States. METHODS: Using the Pulmonary Hypertension Association Registry, we evaluated relationships between the e10 score and demographic, functional, haemodynamic and additional clinical characteristics at baseline and over time. Furthermore, we derived a minimally important difference (MID) estimate for the e10 score. RESULTS: We analysed data from 565 PAH (75% female) adults aged mean±sd 55.6±16.0 years. At baseline, the e10 score had notable correlation with factors expected to impact quality of life in the general population, including age, education level, income, smoking status and body mass index. Clinically important parameters including 6-min walk distance and B-type natriuretic peptide (BNP)/N-terminal proBNP were also significantly associated with e10 score at baseline and over time. We generated a MID estimate for the e10 score of -6.0 points (range -5.0--7.6 points). CONCLUSIONS: The e10 score was associated with demographic and clinical patient characteristics, suggesting that health-related quality of life in PAH is influenced by both social factors and indicators of disease severity. Future studies are needed to demonstrate the impact of the e10 score on clinical decision-making and its potential utility for assessing clinically important interventions.

Enhancing Insights into Pulmonary Vascular Disease through a Precision Medicine Approach. A Joint NHLBI-Cardiovascular Medical Research and Education Fund Workshop Report.

The Division of Lung Diseases of the NHLBI and the Cardiovascular Medical Education and Research Fund held a workshop to discuss how to leverage the anticipated scientific output from the recently launched "Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics" (PVDOMICS) program to develop newer approaches to pulmonary vascular disease. PVDOMICS is a collaborative, protocol-driven network to analyze all patient populations with pulmonary hypertension to define novel pulmonary vascular disease (PVD) phenotypes. Stakeholders, including basic, translational, and clinical investigators; clinicians; patient advocacy organizations; regulatory agencies; and pharmaceutical industry experts, joined to discuss the application of precision medicine to PVD clinical trials. Recommendations were generated for discussion of research priorities in line with NHLBI Strategic Vision Goals that include: (1) A national effort, involving all the stakeholders, should seek to coordinate biosamples and biodata from all funded programs to a web-based repository so that information can be shared and correlated with other research projects. Example programs sponsored by NHLBI include PVDOMICS, Pulmonary Hypertension Breakthrough Initiative, the National Biological Sample and Data Repository for PAH, and the National Precision Medicine Initiative. (2) A task force to develop a master clinical trials protocol for PVD to apply precision medicine principles to future clinical trials. Specific features include: (a) adoption of smaller clinical trials that incorporate biomarker-guided enrichment strategies, using adaptive and innovative statistical designs; and (b) development of newer endpoints that reflect well-defined and clinically meaningful changes. (3) Development of updated and systematic variables in imaging, hemodynamic, cellular, genomic, and metabolic tests that will help precisely identify individual and shared features of PVD and serve as the basis of novel phenotypes for therapeutic interventions.

Vascular Cytokines and Atherosclerosis: Differential Serum Levels of TRAIL, IL-18, and OPG in Obstructive Coronary Artery Disease.

The risk-factor-based prediction of atherosclerotic coronary artery disease (CAD) remains suboptimal, particularly in the absence of any of the standard modifiable cardiovascular risk factors (SMuRFs), making the discovery of biomarkers that correlate with atherosclerosis burden critically important. We hypothesized that cytokines and receptors associated with inflammation in CAD-tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), interleukin-18 (IL-18), and osteoprotegerin (OPG)-would be independently associated with CAD. To determine this, we measured the serum biomarker levels of 993 participants from the BioHEART study who had CT coronary angiograms that were scored for severity of stenosis and plaque composition. We found that the quartiles of TRAIL, OPG, and IL-18 were significantly associated with disease scores, and that the IL-18/TRAIL and OPG/TRAIL ratios demonstrated significant differences between no CAD vs. STEMI whereas only the OPG/TRAIL ratio showed differences between no CAD and obstructive CAD (stenosis > 50%). However, these associations did not persist after adjustment for age, sex, SMuRFs, and a family history of CAD. In conclusion, TRAIL, IL-18, and OPG and the derived ratios of IL-18/TRAIL and OPG/TRAIL demonstrate significant associations with raw disease scores and risk factors, but these markers are not discriminatory biomarkers for the prediction of CAD when incorporated into multi-variable risk models.

Expression of Myeloperoxidase in Patient-Derived Endothelial Colony-Forming Cells-Associations with Coronary Artery Disease and Mitochondrial Function.

BACKGROUND AND AIMS: Myeloperoxidase (MPO) plays a critical role in the innate immune response and has been suggested to be a surrogate marker of oxidative stress and inflammation, with elevated levels implicated in cardiovascular diseases, such as atherosclerosis and heart failure, as well as in conditions like rheumatoid arthritis and cancer. While MPO is well-known in leukocytes, its expression and function in human endothelial cells remain unclear. This study investigates MPO expression in patient-derived endothelial colony-forming cells (ECFCs) and its potential association with CAD and mitochondrial function. METHODS: ECFCs were cultured from the peripheral blood of 93 BioHEART-CT patients. MPO expression and associated functions were examined using qRT-PCR, immunochemistry, flow cytometry, and MPO activity assays. CAD presence was defined using CT coronary angiography (CACS > 0). RESULTS: We report MPO presence in patient-derived ECFCs for the first time. MPO protein expression occurred in 70.7% of samples (n = 41) which had nuclear co-localisation, an atypical observation given its conventional localisation in the granules of neutrophils and monocytes. This suggests potential alternative roles for MPO in nuclear processes. MPO mRNA expression was detected in 66.23% of samples (n = 77). CAD patients had a lower proportion of MPO-positive ECFCs compared to non-CAD controls (57.45% vs. 80%, p = 0.04), a difference that persisted in the statin-naïve sub-cohort (53.85% vs. 84.62%, p = 0.02). Non-CAD patients with MPO expression showed upregulated mitochondrial-antioxidant genes (AIFM2, TXNRD1, CAT, PRDX3, PRDX6). In contrast, CAD patients with MPO gene expression had heightened mROS production and mitochondrial mass and decreased mitochondrial function compared to that of CAD patients without MPO gene expression. CONCLUSIONS: MPO is present in the nucleus of ECFCs. In non-CAD ECFCs, MPO expression is linked to upregulated mitochondrial-antioxidant genes, whereas in CAD ECFCs, it is associated with greater mitochondrial dysfunction.

Health economic analysis of polygenic risk score use in primary prevention of coronary artery disease - A system dynamics model.

Background: Primary prevention programs utilising traditional risk scores fail to identify all individuals who suffer acute cardiovascular events. We aimed to model the impact and cost effectiveness of incorporating a Polygenic risk scores (PRS) into the cardiovascular disease CVD primary prevention program in Australia, using a whole-of-system model. Methods: System dynamics models, encompassing acute and chronic CVD care in the Australian healthcare setting, assessing the cost-effectiveness of incorporating a CAD-PRS in the primary prevention setting. The time horizon was 10-years. Results: Pragmatically incorporating a CAD-PRS in the Australian primary prevention setting in middle-aged individuals already attending a Heart Health Check (HHC) who are determined to be at low or moderate risk based on the 5-year Framingham risk score (FRS), with conservative assumptions regarding uptake of PRS, could have prevented 2, 052 deaths over 10-years, and resulted in 24, 085 QALYs gained at a cost of $19, 945 per QALY with a net benefit of $724 million. If all Australians overs the age of 35 years old had their FRS and PRS performed, and acted upon, 12, 374 deaths and 60, 284 acute coronary events would be prevented, with 183, 682 QALYs gained at a cost of $18, 531 per QALY, with a net benefit of $5, 780 million. Conclusions: Incorporating a CAD-PRS in a contemporary primary prevention setting in Australia would result in substantial health and societal benefits and is cost-effective. The broader the uptake of CAD-PRS in the primary prevention setting in middle-aged Australians, the greater the impact and the more cost-effective the strategy.

Lipidomic Risk Score to Enhance Cardiovascular Risk Stratification for Primary Prevention.

BACKGROUND: Accurate risk stratification is vital for primary prevention of cardiovascular disease (CVD). However, traditional tools such as the Framingham Risk Score (FRS) may underperform within the diverse intermediate-risk group, which includes individuals requiring distinct management strategies. OBJECTIVES: This study aimed to develop a lipidomic-enhanced risk score (LRS), specifically targeting risk prediction and reclassification within the intermediate group, benchmarked against the FRS. METHODS: The LRS was developed via a machine learning workflow using ridge regression on the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab; n = 10,339). It was externally validated with the Busselton Health Study (n = 4,492), and its predictive utility for coronary artery calcium scoring (CACS)-based outcomes was independently validated in the BioHEART cohort (n = 994). RESULTS: LRS significantly improved discrimination metrics for the intermediate-risk group in both AusDiab and Busselton Health Study cohorts (all P < 0.001), increasing the area under the curve for CVD events by 0.114 (95% CI: 0.1123-0.1157) and 0.077 (95% CI: 0.0755-0.0785), with a net reclassification improvement of 0.36 (95% CI: 0.21-0.51) and 0.33 (95% CI: 0.15-0.49), respectively. For CACS-based outcomes in BioHEART, LRS achieved a significant area under the curve improvement of 0.02 over the FRS (0.76 vs 0.74; P < 1.0 × 10-5). A simplified, clinically applicable version of LRS was also created that had comparable performance to the original LRS. CONCLUSIONS: LRS, augmenting the FRS, presents potential to improve intermediate-risk stratification and to predict atherosclerotic markers using a simple blood test, suitable for clinical application. This could facilitate the triage of individuals for noninvasive imaging such as CACS, fostering precision medicine in CVD prevention and management.

Palliative care referrals in patients with pulmonary arterial hypertension: The Pulmonary Hypertension Association Registry.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a life limiting disease with substantial symptom burden and healthcare utilization. Palliative care alleviates physical and emotional symptoms for patients with serious illness, and has been underutilized for these patients. OBJECTIVE: To characterize patients with PAH referred to palliative care and identify predictors of referral. METHODS: We conducted an observational study of adult patients enrolled in the Pulmonary Hypertension Association Registry from January 2015 through June 2021, performing descriptive statistics on patient characteristics at baseline for all patients and the subset referred to palliative care. These characteristics were modeled in a backwards elimination Cox regression with time to referral to palliative care as the primary outcome. RESULTS: 92 of 1,578 patients were referred to palliative care (5.8%); 43% were referred at their last visit prior to death. Referrals were associated with increasing age per decade (hazard ratio 1.35 [95% confidence interval 1.16-1.58]), lower body mass index (hazard ratio 0.97 [95% confidence interval 0.94-0.998]), supplemental oxygen use (hazard ratio 2.01 [95% confidence interval 1.28-3.16]), parenteral prostanoid use (hazard ratio 2.88 [95% confidence interval 1.84-4.51]), and worse quality of life, measured via lower physical (hazard ratio 0.97 [95% confidence interval 0.95-0.99]) and mental (hazard ratio 0.98 [95% confidence interval 0.96-0.995]) scores on the 12-item Short Form Health Survey. CONCLUSION: Patients with PAH are infrequently referred to palliative care, even at centers of excellence. Referrals occur in sicker patients with lower quality of life scores, often close to the end of life.

Serum Soluble Lectin-like Oxidized Low-Density Lipoprotein Receptor-1 (sLOX-1) Is Associated with Atherosclerosis Severity in Coronary Artery Disease.

Risk-factor-based scoring systems for atherosclerotic coronary artery disease (CAD) remain concerningly inaccurate at the level of the individual and would benefit from the addition of biomarkers that correlate with atherosclerosis burden directly. We hypothesized that serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) would be independently associated with CAD and investigated this in the BioHEART study using 968 participants with CT coronary angiograms, which were scored for disease burden in the form of coronary artery calcium scores (CACS), Gensini scores, and a semi-quantitative soft-plaque score (SPS). Serum sLOX-1 was assessed by ELISA and was incorporated into regression models for disease severity and incidence. We demonstrate that sLOX-1 is associated with an improvement in the prediction of CAD severity when scored by Gensini or SPS, but not CACS. sLOX-1 also significantly improved the prediction of the incidence of obstructive CAD, defined as stenosis in any vessel >75%. The predictive value of sLOX-1 was significantly greater in the subgroup of patients who did not have any of the standard modifiable cardiovascular risk factors (SMuRFs). sLOX-1 is associated with CAD severity and is the first biomarker shown to have utility for risk prediction in the SMuRFless population.

Lipidomics Profiling and Risk of Coronary Artery Disease in the BioHEART-CT Discovery Cohort.

The current coronary artery disease (CAD) risk scores for predicting future cardiovascular events rely on well-recognized traditional cardiovascular risk factors derived from a population level but often fail individuals, with up to 25% of first-time heart attack patients having no risk factors. Non-invasive imaging technology can directly measure coronary artery plaque burden. With an advanced lipidomic measurement methodology, for the first time, we aim to identify lipidomic biomarkers to enable intervention before cardiovascular events. With 994 participants from BioHEART-CT Discovery Cohort, we collected clinical data and performed high-performance liquid chromatography with mass spectrometry to determine concentrations of 683 plasma lipid species. Statin-naive participants were selected based on subclinical CAD (sCAD) categories as the analytical cohort (n = 580), with sCAD+ (n = 243) compared to sCAD- (n = 337). Through a machine learning approach, we built a lipid risk score (LRS) and compared the performance of the existing Framingham Risk Score (FRS) in predicting sCAD+. We obtained individual classifiability scores and determined Body Mass Index (BMI) as the modifying variable. FRS and LRS models achieved similar areas under the receiver operating characteristic curve (AUC) in predicting the validation cohort. LRS enhanced the prediction of sCAD+ in the healthy-weight group (BMI < 25 kg/m2), where FRS performed poorly and identified individuals at risk that FRS missed. Lipid features have strong potential as biomarkers to predict CAD plaque burden and can identify residual risk not captured by traditional risk factors/scores. LRS compliments FRS in prediction and has the most significant benefit in healthy-weight individuals.

Clinical Pathway for Coronary Atherosclerosis in Patients Without Conventional Modifiable Risk Factors: JACC State-of-the-Art Review.

Reducing the incidence and prevalence of standard modifiable cardiovascular risk factors (SMuRFs) is critical to tackling the global burden of coronary artery disease (CAD). However, a substantial number of individuals develop coronary atherosclerosis despite no SMuRFs. SMuRFless patients presenting with myocardial infarction have been observed to have an unexpected higher early mortality compared to their counterparts with at least 1 SMuRF. Evidence for optimal management of these patients is lacking. We assembled an international, multidisciplinary team to develop an evidence-based clinical pathway for SMuRFless CAD patients. A modified Delphi method was applied. The resulting pathway confirms underlying atherosclerosis and true SMuRFless status, ensures evidence-based secondary prevention, and considers additional tests and interventions for less typical contributors. This dedicated pathway for a previously overlooked CAD population, with an accompanying registry, aims to improve outcomes through enhanced adherence to evidence-based secondary prevention and additional diagnosis of modifiable risk factors observed.

Clinical Characteristics and Transplant-Free Survival Across the Spectrum of Pulmonary Vascular Disease.

BACKGROUND: PVDOMICS (Pulmonary Vascular Disease Phenomics) is a precision medicine initiative to characterize pulmonary vascular disease (PVD) using deep phenotyping. PVDOMICS tests the hypothesis that integration of clinical metrics with omic measures will enhance understanding of PVD and facilitate an updated PVD classification. OBJECTIVES: The purpose of this study was to describe clinical characteristics and transplant-free survival in the PVDOMICS cohort. METHODS: Subjects with World Symposium Pulmonary Hypertension (WSPH) group 1-5 PH, disease comparators with similar underlying diseases and mild or no PH and healthy control subjects enrolled in a cross-sectional study. PH groups, comparators were compared using standard statistical tests including log-rank tests for comparing time to transplant or death. RESULTS: A total of 1,193 subjects were included. Multiple WSPH groups were identified in 38.9% of PH subjects. Nocturnal desaturation was more frequently observed in groups 1, 3, and 4 PH vs comparators. A total of 50.2% of group 1 PH subjects had ground glass opacities on chest computed tomography. Diffusing capacity for carbon monoxide was significantly lower in groups 1-3 PH than their respective comparators. Right atrial volume index was higher in WSPH groups 1-4 than comparators. A total of 110 participants had a mean pulmonary artery pressure of 21-24 mm Hg. Transplant-free survival was poorest in group 3 PH. CONCLUSIONS: PVDOMICS enrolled subjects across the spectrum of PVD, including mild and mixed etiology PH. Novel findings include low diffusing capacity for carbon monoxide and enlarged right atrial volume index as shared features of groups 1-3 and 1-4 PH, respectively; unexpected, frequent presence of ground glass opacities on computed tomography; and sleep alterations in group 1 PH, and poorest survival in group 3 PH. PVDOMICS will facilitate a new understanding of PVD and refine the current PVD classification. (Pulmonary Vascular Disease Phenomics Program PVDOMICS [PVDOMICS]; NCT02980887).

Protocol for the Stimulating ß3-Adrenergic Receptors for Peripheral Artery Disease (STAR-PAD) trial: a double-blinded, randomised, placebo-controlled study evaluating the effects of mirabegron on functional performance in patients with peripheral arterial disease.

INTRODUCTION: There is currently only one approved medication effective at improving walking distance in people with intermittent claudication. Preclinical data suggest that the ß3-adrenergic receptor agonist (mirabegron) could be repurposed to treat intermittent claudication associated with peripheral artery disease. The aim of the Stimulating ß3-Adrenergic Receptors for Peripheral Artery Disease (STAR-PAD) trial is to test whether mirabegron improves walking distance in people with intermittent claudication. METHODS AND ANALYSIS: The STAR-PAD trial is a Phase II, multicentre, double-blind, randomised, placebo-controlled trial of mirabegron versus placebo on walking distance in patients with PAD. A total of 120 patients aged ≥40 years with stable PAD and intermittent claudication will be randomly assigned (1:1 ratio) to receive either mirabegron (50 mg orally once a day) or matched placebo, for 12 weeks. The primary endpoint is change in peak walking distance as assessed by a graded treadmill test. Secondary endpoints will include: (i) initial claudication distance; (ii) average daily step count and total step count and (iii) functional status and quality of life assessment. Mechanistic substudies will examine potential effects of mirabegron on vascular function, including brachial artery flow-mediate dilatation; MRI assessment of lower limb blood flow, tissue perfusion and arterial stiffness and numbers and angiogenesis potential of endothelial progenitor cells. Given that mirabegron is safe and clinically available for alternative purposes, a positive study is positioned to immediately impact patient care. ETHICS AND DISSEMINATION: The STAR-PAD trial is approved by the Northern Sydney Local Health District Human Research Ethics Committee (HREC/18/HAWKE/50). The study results will be published in peer-reviewed medical or scientific journals and presented at scientific meetings, regardless of the study outcomes. TRIAL REGISTRATION NUMBER: ACTRN12619000423112; Results.