Association of apolipoprotein B and apolipoprotein A1 levels with social determinants of health and coronary artery disease mortality in the United Kingdom Biobank - is there a need for consideration?

BACKGROUND: A higher prevalence of cardiovascular risk factors has previously been shown to be associated with adverse social determinants of health (SDoH) and to explain some of their impact on cardiovascular risk. Whether there is a relationship between lipid parameters, specifically apolipoprotein B (apoB), apolipoprotein A1 (apoA1), their ratio (apoB/apoA1), and SDoH, and whether coronary artery disease (CAD) mortality risk associated with circulating apoB and apoA1 is modified by SDoH was unclear. METHODS: We investigated associations of apoA1, apoB, and apoB/apoA1 with the level of education and household income and their joint impact on CAD mortality in participants of the UK Biobank (UKB) with and without prevalent CAD at enrollment. Hazard ratios for CAD mortality were estimated after adjusting for SDoH and clinical covariates. RESULTS: In 292 804 participants without established CAD, apoB, and the apoB/apoA1 ratio were inversely associated with level of education and household income, whereas apoA1 was positively associated with household income. Adjustment for education level and household income coupled with the number of people living in the household did not attenuate the association between the apolipoprotein levels and incident CAD mortality rates. In a cohort of 13 826 participants with prevalent CAD, apoA1 levels were inversely associated with level of education. Higher apoB levels were only associated with greater CAD mortality risk after adjustment for risk factors. Risk estimation for CAD death through circulating apoA1 levels requires accounting for significant differences by sex. CONCLUSION: Circulating lipid parameters are associated with SDoH in individuals without CAD. CAD mortality risk estimation through apoA1 and apoB levels does not require accounting for SDoH.

Circulating Progenitor Cells and Coronary Collaterals in Chronic Total Occlusion.

BACKGROUND: The role of circulating progenitor cells (CPC) in collateral formation that occurs in the presence of chronic total occlusions (CTO) of a coronary artery is not well established. In stable patients with a CTO, we investigated whether CPC levels are associated with (a) collateral development and (b) ischemic burden, as measured by circulating high sensitivity troponin-I (hsTn-I) levels. METHODS: CPCs were enumerated by flow cytometry as CD45med+ blood mononuclear cells expressing CD34 and both CD34 and CD133 epitopes. The association between CPC counts and both Rentrop collateral grade (0, 1, 2, or 3) and hsTn-I levels were evaluated using multivariate regression analysis, after adjusting for demographic and clinical characteristics. RESULTS: In 89 patients (age 65.5, 72% male, 27% Black), a higher CPC count was positively associated with a higher Rentrop collateral grade; [CD34+ adjusted odds ratio (OR) 1.49 95% confidence interval (CI) (0.95, 2.34) P = 0.082] and [CD34+/CD133+ OR 1.57 95% CI (1.05, 2.36) P = 0.028]. Every doubling of CPC counts was also associated with lower hsTn-I levels [CD34+ ß -0.35 95% CI (-0.49, -0.15) P = 0.002] and [CD34+/CD133+ ß -0.27 95% CI (-0.43, -0.08) P = 0.009] after adjustment. CONCLUSION: Individuals with higher CPC counts have greater collateral development and lower ischemic burden in the presence of a CTO.

Long-Term Outcomes in Patients With Chronic Total Occlusion.

Although a chronic total occlusion (CTO) in the setting of an acute coronary syndrome is associated with greater risk, the prognosis of patients with a CTO and stable coronary artery disease (CAD) remains unknown. This study aimed to investigate adverse event rates in patients with stable CAD with and without a CTO. In 3,597 patients with stable CAD (>50% coronary luminal stenosis) who underwent cardiac catheterization, all-cause mortality, cardiovascular mortality, and the composite major adverse cardiac event (MACE) rates for cardiovascular death, myocardial infarction, and heart failure hospitalization were evaluated. Cox proportional hazards and Fine and Gray subdistribution hazard models were used to compare event-free survival in patient subsets after adjustment for covariates. Event rates were higher in patients with CTOs than in those without CTOs after adjusting for demographic and clinical characteristics (cardiovascular death hazard ratio [HR] 1.29, 95% confidence interval [CI] 1.05 to 1.57, p = 0.012). Patients with CTO revascularization had lower event rates than those of patients without CTO revascularization (cardiovascular death HR 0.43, CI 0.26 to 0.70, p = 0.001). Those with nonrevascularized CTOs were at particularly great risk when compared with those without CTO (cardiovascular death HR 1.52, CI 1.25 to 1.84, p <0.001). Moreover, those with revascularized CTOs had similar event rates to those of patients with CAD without CTOs. Patients with CTO have higher rates of adverse cardiovascular events than those of patients with significant CAD without CTO. This risk is greatest in patients with nonrevascularized CTO.

Does Elevated High-Density Lipoprotein Cholesterol Protect Against Cardiovascular Disease?

High-density lipoprotein (HDL) contributes to reverse cholesterol transport, which is 1 of the main explanations for the described inverse association between HDL-cholesterol (HDL-C) and atherosclerotic cardiovascular disease (ASCVD) risk. However, efforts to therapeutically raise HDL-C levels with niacin, fibrates, or cholesteryl ester transfer protein inhibitors have not demonstrated a reduction in ASCVD events when compared with placebo among individuals treated with statins. Furthermore, mendelian randomization studies suggest that HDL-C is unlikely to be a direct biologic variable impacting ASCVD risk. More recently, observations from well-conducted epidemiologic studies have indicated a nonlinear U-shaped relationship between HDL-C and subclinical atherosclerosis, and that very high HDL-C (≥80 mg/dL in men, ≥100 mg/dL in women) is paradoxically associated with higher all-cause and ASCVD-related mortality. These observations suggest that HDL-C is not a universal protective factor for atherosclerosis. Thus, there are several opportunities for reframing the contribution of HDL-C to ASCVD risk and related clinical calculators. Here, we examine our growing understanding of HDL-C and its role in ASCVD risk assessment, treatment, and prevention. We discuss the biological functions of HDL-C and its normative values in relation to demographics and lifestyle markers. We then summarize original studies that observed a protective association between HDL-C and ASCVD risk and more recent evidence indicating an elevated ASCVD risk at very high HDL-C levels. Through this process, we advance the discussion regarding the future role of HDL-C in ASCVD risk assessment and identify knowledge gaps pertaining to the precise role of HDL-C in atherosclerosis and clinical ASCVD.

Soluble urokinase Plasminogen Activator Receptor (suPAR) mediates the effect of a lower education level on adverse outcomes in patients with coronary artery disease.

AIMS: To investigate whether the adverse impact of lower educational attainment on mortality risk in patients with coronary artery disease (CAD) is mediated by the activation of inflammatory and immune pathways, estimated as elevated soluble urokinase plasminogen activator receptor levels. METHODS AND RESULTS: In 3164 patients undergoing coronary angiography, we investigated multivariable associations between suPAR and educational attainment and assessed the relationship between a lower educational level (defined as a high-school degree or less as the highest educational qualification) and outcomes using Cox proportional hazard and Fine and Gray's subdistribution competing risk models. The potential mediating effect through suPAR and high-sensitivity C-reactive protein (hs-CRP) was assessed using mediation analysis. A total of 1814 patients (57.3%) had achieved a higher (≥college) education level and 1350 patients (42.7%) a lower (≤high school) education level. Soluble urokinase plasminogen activator receptor levels were 9.0% [95% confidence interval (CI) 6.3-11.8, P ≤ 0.0001] higher in patients with lower educational qualifications than in those with higher educational qualifications after covariate adjustment. Lower educational attainment was associated with a higher risk of cardiovascular death after adjustment for demographic, clinical, and behavioural covariates, including CAD severity and heart failure history, medication use, and hs-CRP levels [hazard ratio 1.26 (95% CI 1.02-1.55, P = 0.03)]. However, after adjustment for suPAR levels, the effect of a lower educational level on cardiovascular death became insignificant. Values were similar for all-cause death. Soluble urokinase plasminogen activator receptor levels mediated 49% and hs-CRP levels 17% of the cardiovascular death risk attributable to lower educational attainment. CONCLUSION: Circulating suPAR levels importantly mediate the effects of lower educational attainment on mortality, indicating the importance of systemic inflammation and immune dysregulation as biologic mediators of adverse social determinants of health.

In patients with coronary artery disease (CAD), we demonstrate that nearly half of the higher risk of all-cause and cardiovascular mortality associated with lower educational attainment as a measure of socioeconomic status is mediated by systemic inflammation and immune dysregulation, which can be estimated by measuring the circulating soluble urokinase plasminogen activator receptor (suPAR) levels. Even after accounting for differences in cardiovascular risk factors, lower educational attainment is associated with higher mortality risk in patients with CAD and there is activation of inflammatory pathways and immune dysregulation in those with lower (≤high school) educational attainment than in those with higher (≥college) educational attainment, estimated as higher circulating suPAR levels.Almost half of the higher risk for adverse outcomes observed in those with lower educational attainment appears to be due to systemic inflammation and immune dysregulation and can be estimated from measuring suPAR levels.

Immune Activation Mediates the Association of Advanced Hepatic Fibrosis With Adverse Outcomes in Patients With Coronary Artery Disease.

BACKGROUND: Literature suggests a bidirectional association between advanced hepatic fibrosis (AHF) and coronary artery disease (CAD). We evaluated the association of AHF with immune activation, systemic inflammation, and adverse outcomes in patients with CAD. METHODS AND RESULTS: A fibrosis-4 index cutoff value ≥2.67 was used to define AHF. Circulating levels of soluble urokinase plasminogen activator receptor and hsCRP (high-sensitivity C-reactive protein) were measured as markers for immune activation and systemic inflammation, respectively. The relationship of AHF with soluble urokinase plasminogen activator receptor, hsCRP, and adverse cardiovascular outcomes was evaluated. Among 3406 participants with CAD, 479 had AHF. Participants with AHF were older; were less likely to be Black individuals; and had a lower body mass index, worse renal function, and a prior history of heart failure. In multivariable linear regression models adjusted for clinical and demographic confounders, participants with AHF had 15.6% higher soluble urokinase plasminogen activator receptor and 24.0% higher hsCRP levels. They were more likely to experience the following adverse outcomes: all-cause death (adjusted hazard ratio [HR], 1.57 ([95% CI, 1.29-1.92]; P<0.001) and cardiovascular death: (subdistribution HR, 1.50 [95% CI, 1.14-1.95]; P=0.003). Mediation analysis showed that 47.0% (95% CI, 13.6%-81.2%]; P=0.006) of the indirect effect of AHF on cardiovascular death was mediated by circulating soluble urokinase plasminogen activator receptor levels. CONCLUSIONS: AHF is independently associated with immune activation, systemic inflammation, and adverse cardiovascular outcomes in patients with CAD. The association of AHF with adverse outcomes is partly mediated by immune activation, and targeting this pathway may help reduce the residual risk in patients with CAD.

High Sensitivity Troponin Level and Benefits of Chronic Total Occlusion Revascularization.

Background The survival benefit of revascularization of chronic total occlusion (CTO) of the coronary arteries remains a subject of controversy. We measured high sensitivity troponin-I (hsTn-I) levels as an estimate of myocardial ischemia in patients with stable coronary artery disease, with the hypothesis that (1) patients with CTO have higher levels of hsTn-I than patients without CTO, (2) hsTn-I levels will predict adverse cardiovascular events in patients with CTO, and (3) patients with elevated hsTn-I levels will have a survival benefit from CTO revascularization. Methods and Results In 428 patients with stable coronary artery disease and CTO undergoing coronary angiography, adverse event rates were investigated. Cox proportional hazards models and Fine and Gray subdistribution hazard models were performed to determine the association between hsTn-I level and incident event rates in patients with CTO. HsTn-I levels were higher in patients with compared with those without CTO (median 6.7 versus 5.6 ng/L, P=0.002). An elevated hsTn-I level was associated with higher adverse event rates (adjusted all-cause mortality hazard ratio, 1.19 [95% CI, 1.08-1.32]; P=0.030) for every doubling of hsTn-I level. CTO revascularization was performed in 28.3% of patients. In patients with a high (>median) hsTn-I level, CTO revascularization was associated with substantially lower all-cause mortality (adjusted hazard ratio, 0.26 [95% CI, 0.08-0.88]; P=0.030) compared with those who did not undergo revascularization. In patients with a low (

Aggregate Clinical and Biomarker-Based Model Predicts Adverse Outcomes in Patients With Coronary Artery Disease.

Despite guideline-based therapy, patients with coronary artery disease (CAD) are at widely variable risk for cardiovascular events. This variability demands a more individualized risk assessment. Herein, we evaluate the prognostic value of 6 biomarkers: high-sensitivity C-reactive protein, heat shock protein-70, fibrin degradation products, soluble urokinase plasminogen activator receptor, high-sensitivity troponin I, and B-type natriuretic peptide. We then develop a multi-biomarker-based cardiovascular event prediction model for patients with stable CAD. In total, 3,115 subjects with stable CAD who underwent cardiac catheterization at Emory (mean age 62.8 years, 17% Black, 35% female, 57% obstructive CAD, 31% diabetes mellitus) were randomized into a training cohort to identify biomarker cutoff values and a validation cohort for prediction assessment. Main outcomes included (1) all-cause death and (2) a composite of cardiovascular death and nonfatal myocardial infarction (MI) within 5 years. Elevation of each biomarker level was associated with higher event rates in the training cohort. A biomarker risk score was created using optimal cutoffs, ranging from 0 to 6 for each biomarker exceeding its cutoff. In the validation cohort, each unit increase in the biomarker risk score was independently associated with all-cause death (hazard ratio 1.62, 95% confidence interval [CI] 1.45 to 1.80) and cardiovascular death/MI (hazard ratio 1.52, 95% CI 1.35 to 1.71). A biomarker risk prediction model for cardiovascular death/MI improved the c-statistic (∆ 6.4%, 95% CI 3.9 to 8.8) and net reclassification index by 31.1% (95% CI 24 to 37), compared with clinical risk factors alone. Integrating multiple biomarkers with clinical variables refines cardiovascular risk assessment in patients with CAD.

A Pilot Study of Neurobiological Mechanisms of Stress and Cardiovascular Risk.

Objective: Coronary heart disease is a leading cause of death and disability. Although psychological stress has been identified as an important potential contributor, mechanisms by which stress increases risk of heart disease and mortality are not fully understood. The purpose of this study was to assess mechanisms by which stress acts through the brain and heart to confer increased CHD risk. Methods: Coronary Heart Disease patients (N=10) underwent cardiac imaging with [Tc-99m] sestamibi single photon emission tomography at rest and during a public speaking mental stress task. Patients returned for a second day and underwent positron emission tomography imaging of the brain, heart, bone marrow, aorta (indicating inflammation) and subcutaneous adipose tissue, after injection of [18F]2-fluoro-2-deoxyglucose for assessment of glucose uptake followed mental stress. Patients with (N=4) and without (N=6) mental stress-induced myocardial ischemia were compared for glucose uptake in brain, heart, adipose tissue and aorta with mental stress. Results: Patients with mental stress-induced ischemia showed a pattern of increased uptake in the heart, medial prefrontal cortex, and adipose tissue with stress. In the heart disease group as a whole, activity increase with stress in the medial prefrontal brain and amygdala correlated with stress-induced increases in spleen (r=0.69, p=0.038; and r=0.69, p=0.04 respectfully). Stress-induced frontal lobe increased uptake correlated with stress-induced aorta uptake (r=0.71, p=0.016). Activity in insula and medial prefrontal cortex was correlated with post-stress activity in bone marrow and adipose tissue. Activity in other brain areas not implicated in stress did not show similar correlations. Increases in medial prefrontal activity with stress correlated with increased cardiac glucose uptake with stress, suggestive of myocardial ischemia (r=0.85, p=0.004). Conclusions: These findings suggest a link between brain response to stress in key areas mediating emotion and peripheral organs involved in inflammation and hematopoietic activity, as well as myocardial ischemia, in Coronary Heart Disease patients.

Circulating progenitor cells and outcomes in patients with coronary artery disease.

BACKGROUND: Low quantities of circulating progenitor cells (CPCs), specifically CD34+ populations, reflect impairment of intrinsic regenerative capacity. This study investigates the relationship between subsets of CPCs and adverse outcomes. METHODS: 1366 individuals undergoing angiography for evaluation of coronary artery disease (CAD) were enrolled into the Emory Cardiovascular Biobank. Flow cytometry identified CPCs as CD45med blood mononuclear cells expressing the CD34 epitope, with further enumeration of hematopoietic CPCs as CD133+/CXCR4+ cells and endothelial CPCs as vascular endothelial growth factor receptor-2 (VEGFR2+) cells. Adjusted Cox or Fine and Gray's sub-distribution hazard regression models analyzed the relationship between CPCs and 1) all-cause death and 2) a composite of cardiovascular death and non-fatal myocardial infarction (MI). RESULTS: Over a median 3.1-year follow-up period (IQR 1.3-4.9), there were 221 (16.6%) all-cause deaths and 172 (12.9%) cardiovascular deaths/MIs. Hematopoietic CPCs were highly correlated, and the CD34+/CXCR4+ subset was the best independent predictor. Lower counts (≤median) of CD34+/CXCR4+ and CD34+/VEGFR2+ cells independently predicted all-cause mortality (HR 1.46 [95% CI 1.06-2.01], p = 0.02 and 1.59 [95% CI 1.15-2.18], p = 0.004) and cardiovascular death/MI (HR 1.50 [95% CI 1.04-2.17], p = 0.03 and 1.47 [95% CI 1.01-2.03], p = 0.04). A combination of low CD34+/CXCR4+ and CD34+/VEGFR2+ CPCs predicted all-cause death (HR 2.1, 95% CI 1.4-3.0; p = 0.0002) and cardiovascular death/MI (HR 2.0, 95% CI 1.3-3.2; p = 0.002) compared to those with both lineages above the cut-offs. CONCLUSIONS: Lower levels of hematopoietic and endothelial CPCs indicate diminished endogenous regenerative capacity and independently correlate with greater mortality and cardiovascular risk in patients with CAD.

U-shaped relationship between apolipoprotein A1 levels and mortality risk in men and women.

BACKGROUND: Apolipoprotein A1 (ApoA1) is the principal protein component of high-density lipoprotein (HDL). Although low HDL cholesterol (HDL-C) levels are known to be associated with greater cardiovascular risk, recent studies have also shown heightened mortality risk at very high HDL-C levels. AIMS: To investigate the sex-specific association between elevated ApoA1 levels and adverse outcomes, and their genetic basis. METHODS: A prospective cohort study of United Kingdom Biobank participants without coronary artery disease at enrollment was performed. The primary exposure was serum ApoA1 levels. The primary and secondary outcome measures were cardiovascular and all-cause death, respectively. RESULTS: In 402 783 participants followed for a median of 12.1 years, there was a U-shaped relationship between ApoA1 levels and both cardiovascular as well as all-cause mortality, after adjustment for traditional cardiovascular risk factors. Individuals in the highest decile of ApoA1 levels (1.91-2.50 g/L) demonstrated higher cardiovascular (HR 1.21, 95% CI 1.07-1.37, P < 0.0022) and all-cause mortality (HR 1.14, 95% CI 1.07-1.21, P < 0.0001) compared with those within the lowest risk eighth decile (1.67-1.75 g/L). The U-shaped relationship was present in both sexes, though more pronounced in men. Sensitivity analyses showed that cardiovascular mortality rates were higher in those with greater alcohol intake (P < 0.004). Adjustment for polygenic variation associated with higher ApoA1 levels did not attenuate the effect of very high ApoA1 levels on mortality. In the sub-group with very elevated HDL-C levels (> 80 mg/dL in men, > 100 mg/dL in women), there was no association between ApoA1 levels and mortality. CONCLUSION: Both very low and very elevated ApoA1 levels are associated with higher cardiovascular and all-cause mortality.

Vascular Regenerative Capacity and the Obesity Paradox in Coronary Artery Disease.

[Figure: see text].

Sex Differences in Circulating Soluble Urokinase-Type Plasminogen Activator Receptor (suPAR) Levels and Adverse Outcomes in Coronary Artery Disease.

Background Women have higher circulating levels of soluble urokinase-type plasminogen activator receptor (suPAR), and elevated suPAR is associated with cardiovascular risk. The independent association of sex with suPAR and the impact of sex on its association with cardiovascular risk are unknown. Methods and Results Plasma suPAR was measured using ELISA in 2 cohorts of 666 asymptomatic individuals (49 years, 65% women) and 4184 patients with coronary artery disease (63 years, 37% women). Independent association of sex with suPAR was studied using linear regression models adjusted for demographics, risk factors, and visceral adiposity in asymptomatic participants. Impact of sex on association of suPAR with all-cause mortality was studied in patients with coronary artery disease using multivariable-adjusted Cox models. Sex-specific suPAR cutoffs for predicting all-cause mortality were calculated. Asymptomatic women had 10% higher suPAR compared with men after adjusting for confounders, and visceral adiposity partly accounted for this association. Over a median follow-up of 5.2 years, 795 deaths were recorded in patients with coronary artery disease. Log2-transformed suPAR was independently associated with mortality (hazard ratio per 1-SD 1.72, 95% CI 1.60-1.85) and an interaction with sex was noted (P=0.005). Association of suPAR with mortality was slightly weaker in women (hazard ratio 1.61, 95% CI 1.41-1.83) compared with men (hazard ratio 1.83, 95% CI 1.67-2.00). However, using sex-specific suPAR cut-offs (4392 pg/mL for women and 3187 pg/mL for men), a similar mortality incidence was observed for both sexes (38.5% and 35.5%, respectively, P=0.3). Conclusions Women have 10% higher plasma suPAR levels compared with men. Elevated sex-specific plasma suPAR levels are equally predictive of risk of adverse events in both sexes.