Serum phosphate is associated with aortic valve calcification in the Multi-ethnic Study of Atherosclerosis (MESA)

Differences in risk factors associated with the initiation and progression of mitral annular calcification in asymptomatic individuals

Mitral annular calcification (MAC) is hypothesized to be a representation of atherosclerosis and is associated with adverse outcomes. However, the pathophysiology and risk factors associated with MAC development are not fully understood. Using the KOrea Initiatives on Coronary Artery (KOICA) registry, 738 asymptomatic individuals who underwent health screening with echocardiography and serial cardiac computed tomography (CT) were included for analysis. MAC was identified on CT, and the severity was quantified using Agatston units (AU). Risk factors associated with prevalent MAC and the rate of MAC progression were identified using multivariable regression models. On initial CT, 52 (7.0%) participants showed prevalent MAC, and in this group the median MAC progression rate was 3.4 AU/year (interquartile range: 0.2-14.7) during a median interscan duration of 36.4 months. Factors associated with prevalent MAC were older age (p < 0.001), higher body-mass index (p = 0.04), diabetes (p < 0.01), higher systolic blood pressure (p < 0.01), and higher left atrial volume index (p = 0.02). Meanwhile, factors associated with faster MAC progression were initial MAC severity (p < 0.001), male sex (p < 0.01), and higher serum phosphate (p < 0.001). Traditional atherosclerotic risk factors have an important role in the initial process of MAC development. The association between left atrial volume index and prevalent MAC further suggests the implication of elevated left ventricular filling pressure in MAC initiation. Conversely, initial MAC severity and mineral metabolism were found to be major determinants in the later phase of MAC progression.

The association of bisphosphonates, calcium levels and PTH levels with bioprosthetic aortic valve degeneration

BACKGROUND

Bioprosthetic aortic valve (bAV) degeneration represents a major concern following aortic valve replacement (AVR). The association of bisphosphonates, serum calcium and serum parathyroid hormone (PTH) with native AV degeneration have been studied extensively. However, their association with structural valve degeneration (SVD) is yet to be elucidated.

METHODS

Patients who underwent AVR and had a baseline transthoracic echocardiogram (TTE) and at least one follow-up TTE spaced three months apart were included. SVD diagnosis was made according to American Society of Echocardiography guidelines. Patients' exposure to bisphosphonates and serum calcium and PTH levels were collected. A cutoff of 10.2 mg/dL for calcium and 65 pg/mL for PTH were used, respectively, to define pathological thresholds. Multivariable Cox proportional hazards regression models were built to evaluate the association between predictors and SVD.

RESULTS

Overall, 2002 patients were included, of whom 214 (10.7 %) had SVD, with median degeneration time of 4 (IQR: 1.9, 6.1) years. Among them, reintervention occurred in 82 (4.1 %) without significant differences according to bisphosphonate use (Log Rank p = 0.300), elevated PTH or calcium levels (Log Rank p = 0.702 and p = 0.703, respectively). In the multivariate analysis, neither bisphosphonates use (HR: 0.95, 95 % CI: 0.56-1.60; p = 0.862), elevated calcium levels >10.2 mg/dL (HR: 0.74, 95 % CI: 0.31-1.72; p = 0.489), nor elevated PTH levels >65 pg/mL (HR: 1.91, 95 % CI: 0.99-3.68; p = 0.052) was associated with SVD.

CONCLUSIONS

The use of bisphosphonates, elevated serum calcium levels and elevated serum PTH levels were not associated with SVD nor with reintervention on the bAV.

Advances in Pathophysiological Mechanisms of Degenerative Aortic Valve Disease

Degenerative aortic valve disease (DAVD) represents the most prevalent valvular ailment among the elderly population, which significantly impacts their physical well-being and potentially poses a lethal risk. Currently, the underlying mechanisms of DAVD remain incompletely understood. While the progression of this disease has traditionally been attributed to degenerative processes associated with aging, numerous recent studies have revealed that heart valve calcification may represent a response of valve tissue to a specific initiating factor, involving the interaction of various genes and signaling pathways. This calcification process is further influenced by a range of factors, including genetic predispositions, environmental exposures, metabolic factors, and hemodynamic considerations. Based on the identification of its biomarkers, potential innovative therapeutic targets are proposed for the treatment of this complex condition. The present article primarily delves into the underlying pathophysiological mechanisms and advancements in diagnostic and therapeutic modalities pertaining to this malady.

The Role of Serum Calcium Levels in the Progression of Arterial Stiffness: Cross-Sectional and Longitudinal Analyses in a Multicenter Cohort

Increased arterial stiffness measured by brachial-ankle pulse wave velocity (baPWV) is a well-known risk factor for hypertension and future cardiovascular events. The relationship between serum calcium levels and increased arterial stiffness is not well understood. Individuals undergoing baPWV measurements as part of a generalized health examination, with normal serum calcium (8.5-10.5 mg/dL) and phosphate levels and no significant renal dysfunction, were selected from the Korea Initiatives on Coronary Artery (KOICA) registry. The cross-sectional relationship between serum calcium levels and baPWV, and the longitudinal effect of baseline serum calcium levels on baPWV progression in those with repeated baPWV measurements, were analyzed using multivariable regression models. A total of 9150 individuals with baseline baPWV and 2329 individuals (5451 PWV measurements) with follow-up baPWV were selected for cross-sectional and longitudinal analyses, respectively. After adjustment for confounders, higher serum calcium levels were associated with increased baseline baPWV (β-coefficient per 1 mg/dL increase, 19.61; 95% CI 7.77-31.45; p = 0.001). Higher serum calcium was also independently associated with a greater annualized baPWV progression rate longitudinally (β-coefficient per 1 mg/dL increase, 5.17; 95% CI, 1.82-8.67; p = 0.004). Subgroup analysis showed that the effect of serum calcium on baPWV progression had a significant interaction with baseline baPWV, systolic blood pressure, and the presence of diabetes (interaction p < 0.001). In conclusion, higher serum calcium levels within the normal range were associated with faster arterial stiffness progression measured by baPWV. Further studies are required to explore the potential for modulating calcium metabolism to slow arterial stiffness progression.

Cardiovascular status in chronic hypoparathyroidism: a systematic cross-sectional assessment in 168 patients

OBJECTIVE

Long-term complications such as renal diseases are well known in patients with chronic hypoparathyroidism (hypoPT), but risk of cardiovascular comorbidity remains less clear. This study comprehensively assessed cardiovascular parameters in hypoPT compared to matched controls.

DESIGN

Cross-sectional cohort study involving 168 patients with chronic hypoPT.

METHODS

Patients underwent electrocardiograms, blood pressure measurements, and echocardiography. A 1:3 propensity score matching was performed with individuals from the German population-based Study of Health in Pomerania (SHIP-TREND) and the "Characteristics and Course of Heart Failure Stages A-B" (STAAB) cohort.

RESULTS

HypoPT showed significantly higher systolic (128 vs 125 mm Hg, P = .02) and diastolic blood pressures (83 vs 77 mm Hg, P < .01). Intake of antihypertensives was similar between groups. The QTc interval was markedly prolonged (438 vs 420 ms, P < .01) with QTc interval prolongation occurring significantly more frequently in hypoPT (24% vs 6%, P < .01). Interestingly, echocardiography revealed significantly lower left ventricular mass index (28 vs 43 g/m2.7, P < .01) and less frequent left ventricular hypertrophy (7%% vs 41%, P < .01) in hypoPT but comparable left ventricular ejection fraction (P = .48). HypoPT patients had higher prevalence of mitral (20 vs 0%, P < .01) and aortic valve stenoses (7 vs 2%, P < .01). Comparison with STAAB confirmed the increased prevalence of arterial hypertension and reduced myocardial mass indices.

CONCLUSIONS

Patients with hypoPT exhibit a higher prevalence of QTc interval prolongation despite established therapy and an increased incidence of hypertension. Conversely, echocardiography revealed lower left ventricular mass and less frequent left ventricular hypertrophy in hypoPT, but higher prevalence of valve stenosis. Regular monitoring of hypertension, QTc interval prolongation, and valve stenosis is recommended to reduce the risk of cardiovascular diseases.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05585593.

Inactive Matrix Gla Protein and Cardiovascular Outcomes: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

MGP (matrix Gla protein) inhibits arterial calcification. Higher inactive MGP, in its dephosphorylated-uncarboxylated (dp-uc) form, is positively associated with vascular calcification, possibly portending adverse cardiovascular events. The objective of this study was to determine the association of dp-ucMGP with incident cardiovascular disease (CVD) events and mortality in MESA (Multi-Ethnic Study of Atherosclerosis).

METHODS

MESA is a prospective cohort study of 45- to 84-year-old individuals enrolled between 2000 and 2002 with adjudicated outcomes through 2019. Dp-ucMGP was measured at baseline in n=2663 participants with cardiac computed tomography at Exams 1 (2000-2002) and 5 (2010-2012). Age-stratified Cox proportional hazard models were used to assess dp-ucMGP with risk of all CVD (mean follow-up 16±4 years), hard CVD (17±3 years), hard coronary heart disease (17±3 years), and all-cause mortality (18±2 years).

RESULTS

The youngest age quartile (45- to 53-years-old) with higher dp-ucMGP levels (520-2934 pmol/L) had an increased risk of all CVD (hazard ratio [HR], 3.05 [95% CI, 1.58-5.90], P=0.001), hard CVD (HR, 2.85 [95% CI, 1.30-6.23], P=0.009), hard coronary heart disease (HR, 3.79 [95% CI, 1.31-10.95], P=0.014), and all-cause mortality (HR, 2.73 [95% CI, 1.19-6.30], P=0.018) compared with those with dp-ucMGP levels between 150 and 519 pmol/L in maximally adjusted models.

CONCLUSIONS

Younger individuals 45 to 53 years old with elevated dp-ucMGP levels (≥520 pmol/L) had an increased risk of incident CVD, coronary heart disease, and all-cause mortality. No association was seen in older adults. Additional studies are needed to better delineate the relationship of inactive MGP with incident CVD, coronary heart disease, and all-cause mortality.

Valvular calcification in chronic kidney disease: new insights from recent clinical and preclinical studies

Valvular calcification, developing either in the mitral or the aortic valve, is highly prevalent in patients suffering from chronic kidney disease (CKD), in whom their presence correlates with higher cardiovascular and all-cause mortality risk. To date, the exact mechanisms that promote heart valve calcification remain unclear, and none of the treatments tested so far have shown efficacy in preventing valvular fibrocalcific remodelling. It is therefore essential to improve our understanding of the mechanisms involved in the pathological process if we are to find new, effective therapies. The purpose of this review is to (i) summarize our current knowledge of the mechanisms by which CKD and related therapies affect valvular cell activity, (ii) present the latest therapeutic targets identified in preclinical studies, and (iii) discuss the most recent clinical trials evaluating the efficacy of therapies aimed at preventing valvular calcification in CKD.

Fibroblast Growth Factors in Cardiovascular Disease

Despite advancements in managing traditional cardiovascular risk factors, many cardiovascular diseases (CVDs) persist. Fibroblast growth factors (FGFs) have emerged as potential diagnostic markers and therapeutic targets for CVDs. FGF1, FGF2, and FGF4 are primarily used for therapeutic angiogenesis. Clinical applications are being explored based on animal studies using approaches such as recombinant protein administration and adenovirus-mediated gene delivery, targeting patients with coronary artery disease and lower extremity arterial disease. Although promising results have been observed in animal models and early-stage clinical trials, further studies are required to assess their therapeutic potential. The FGF19 subfamily, consisting of FGF19, FGF21, and FGF23, act via endocrine signaling in various organs. FGF19, primarily expressed in the small intestine, plays important roles in glucose, lipid, and bile acid metabolism and has therapeutic potential for metabolic disorders. FGF21, found in various tissues, improves glucose metabolism and insulin sensitivity, suggesting potential for treating obesity and diabetes. FGF23, primarily secreted by osteocytes, regulates vitamin D and phosphate metabolism and serves as an important biomarker for chronic kidney disease and CVDs. Thus, FGFs holds promise for both therapeutic and diagnostic applications in metabolic and cardiovascular diseases. Understanding the mechanisms of FGF may pave the way for novel strategies to prevent and manage CVDs, potentially addressing the limitations of current treatments. This review explores the roles of FGF1, FGF2, FGF4, and the FGF19 subfamily in maintaining cardiovascular health. Further research and clinical trials are crucial to fully understand the therapeutic potential of FGFs in managing cardiovascular health.

Higher serum phosphate within the normal range is associated with the development of calcified aortic valve disease

Background

Despite the essential role of ectopic osteogenic calcium-phosphate metabolism in the development of calcific aortic valve disease (CAVD), the implications of high serum phosphate levels in CAVD development are not fully understood.

Methods

Asymptomatic individuals who underwent health screening using serial cardiac computed tomography (CT) and echocardiography were selected from a multicenter registry. CAVD was identified and quantified on CT images using the aortic valve calcification (AVC) score. The associations between initial serum phosphate levels and the presence of baseline CAVD, development of new CAVD, and the AVC score progression rate were investigated using multivariable regression models.

Results

A total of 736 individuals were selected for analysis, and the median interscan duration was 36.4 months. On initial CT, 83 (13.7%) participants had baseline CAVD, while 52 (7.0%) individuals developed new CAVD during follow-up. Serum phosphate levels were not associated with a higher probability of baseline CAVD but were predictive of newly developed CAVD (odds ratio per 1 mg/dl, 1.05; 95% confidence interval, 1.01-1.10; p = 0.02). Higher phosphate levels were also associated with a faster AVC score progression in those with baseline CAVD (regression coefficient per 1 mg/dl, 15.55 Agatston units/year; 95% confidence interval, 6.02-25.07; p < 0.01), an association which remained significant when the analysis was extended to include newly developed CAVD.

Conclusion

Even slight elevations in serum phosphate are associated with accelerated CAVD progression from an early stage. Further studies are needed to investigate whether the regulation of phosphate metabolism can slow the progression of CAVD to aortic stenosis.

Short-term therapy with R568 ameliorated secondary hyperparathyroidism but does not prevent aortic valve calcification in uremic rats

Introduction

Renal failure associated aortic valve calcification (AVC) is the result of hyperphosphatemia and hyperparathyroidism. Calcimimetics is an effective tool for management of secondary hyperparathyroidism. Our goal was to evaluate the effect of the medical intervention with calcimimetic R568 on the AVC process.

Methods and results

The experimental design consisted of administering a uremia-inducing phosphate-enriched diet to rats for six weeks. Rats received a daily R568 injection at different times. Biochemical analysis demonstrated increased urea (34.72 ± 3.57 vs. 5.18 ± 0.15 mmol/L, p<0.05) and creatinine (293.93 ± 79.6 vs. 12.82 ± 1.56 µmol/L, p<0.05). R568 treatment markedly reduced parathyroid hormone (PTH) levels in both treated groups (192.63 ± 26.85, 301.23 ± 101.79 vs. 3570 ± 986.63 pg/mL, p<0.05), with no impact on serum calcium and phosphate. von Kossa staining showed increase in AVC in uremic rats compared to control (1409 ± 159.5 vs. 27.33 ± 25.83, p<0.05). AVC was not affected by R568 in both groups (3343 ± 2462, 1593 ± 792 vs. 1409 ± 159.5, NS). Similarly, the inflammatory marker CD68 was elevated in uremic rats (15592 ± 3792 vs. 181.8 ± 15.29, p<0.01), and was not influenced by R568 treatment (8453 ± 818.5, 9318 ± 2232 vs. 15592 ± 3792, NS). Runt-related transcription factor 2 (Runx2), the regulator of osteoblast differentiation, was upregulated in uremic rats (23186 ± 9226 vs. 3184 ± 2495), that accompanied by elevated levels of Osteopontin (158395 ± 45911 vs. 237.7 ± 81.5, p<0.05) and Osteocalcin (22203 ± 8525 vs. 489.7 ± 200.6, p<0.05). R568 had no impact on osteoblastic markers (Runx2: 21743 ± 3193, 23004 ± 10871 vs. 23186 ± 9226, NS; osteopontin: 57680 ± 19522, 137116 ± 60103 vs. 158395 ± 45911, NS; osteocalcin: 10496 ± 5429, 8522 ± 5031 vs. 22203 ± 8525, NS).

Conclusion

In an adenine-induced uremic rat model, we showed that short-term R568 therapy had no effect on AVC. Treatment with R568 decreased PTH levels but had no effect on high phosphate levels. Regression of AVC necessitates not only a decrease in PTH levels, but also a decline in phosphate levels. To achieve improved outcomes, it is advisable to consider administering a combination of R568 with other medications, such as calcium supplements or phosphate binders. Additional studies are required for further evaluation of the potential treatment of chronic kidney disease (CKD)-associated AVC.

Pathological Mechanism and Treatment of Calcified Aortic Stenosis

Calcified aortic stenosis (AS) is one of the most common valvular heart diseases worldwide, characterized by progressive fibrocalcific remodeling and thickening of the leaflets, which ultimately leads to obstruction of blood flow. Its pathobiology is an active and complicated process, involving endothelial cell dysfunction, lipoprotein deposition and oxidation, chronic inflammation, phenotypic transformation of valve interstitial cells, neovascularization, and intravalvular hemorrhage. To date, no targeted drug has been proven to slow down or prevent disease progression. Aortic valve replacement is still the optimal treatment of AS. This article reviews the etiology, diagnosis, and management of calcified aortic stenosis and proposes novel potential therapeutic targets.

Matrix Gla protein and the long-term incidence and progression of coronary artery and aortic calcification in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

Matrix Gla protein (MGP) is an inhibitor of calcification that requires carboxylation by vitamin K for activity. The inactive form of MGP, dephosphorylated-uncarboxylated matrix Gla protein (dp-ucMGP), has been associated with increased calcification. However, it is not known whether there is a longitudinal relationship between dephosphorylated-uncarboxylated matrix Gla protein levels and coronary and aortic calcification in large population cohorts.

METHODS

The Multi-Ethnic Study of Atherosclerosis (MESA) followed participants with serial cardiac computed tomography (CT) measures of vascular calcification. Dp-ucMGP was measured at baseline in a subset of participants who completed baseline and follow-up CTs approximately 10 years later and had available plasma specimens (n = 2663). Linear mixed effects models (LMMs) were used to determine the association of dp-ucMGP with the simultaneous incidence and progression of coronary artery, ascending thoracic aortic, or descending thoracic aortic calcification (CAC, ATAC, DTAC)].

RESULTS

For every one standard deviation (SD, 178 pmol/L) increment in dp-ucMGP, CAC increased by 3.44 ([95% CI = 1.68, 5.21], p < 0.001) Agatston units/year (AU/year), ATAC increased by 0.63 ([95% CI = 0.27, 0.98], p = 0.001) AU/year, and DTAC increased by 8.61 ([95% CI = 4.55, 12.67], p < 0.001) AU/year. The association was stronger for DTAC in those ≥65 years and with diabetes.

CONCLUSIONS

We found a positive association of the inactive form of matrix Gla protein, dp-ucMGP, and long-term incidence/progression of CAC, ATAC, and DTAC. Future studies should investigate dp-ucMGP as a calcification regulator and MGP as a possible therapeutic target to slow progression of calcification in the vasculature.

Role of klotho and fibroblast growth factor 23 in arterial calcification, thickness, and stiffness: a meta-analysis of observational studies

This meta-analysis was conducted to clarify the role of klotho and fibroblast growth factor 23 (FGF-23) in human arterial remodeling across recent studies, in terms of arterial calcification, thickness, and stiffness. A systematic literature search was conducted on five databases for articles up to December 2023. Arterial calcification, thickness, and stiffness were determined using the calcification score and artery affected, carotid intima-media thickness (CIMT), and pulse wave velocity (PWV), respectively. Sixty-two studies with a total of 27,459 individuals were included in this meta-analysis. Most studies involved chronic kidney disease patients. Study designs were mostly cross-sectional with only one case-control and nine cohorts. FGF-23 was positively correlated with arterial calcification (r = 0.446 [0.254-0.611], p < 0.0001 and aOR = 1.36 [1.09-1.69], p = 0.006), CIMT (r = 0.188 [0.02-0.354], p = 0.03), and PWV (r = 0.235 [0.159-0.310], p < 0.00001). By contrast, Klotho was inversely correlated with arterial calcification (r = - 0.388 [- 0.578 to - 0.159], p = 0.001) and CIMT (r = - 0.38 [- 0.53 to - 0.207], p < 0.00001). In conclusion, FGF-23 and Klotho were associated with arterial calcification, thickness, and stiffness, clarifying their role in arterial remodeling processes.

Clinical Implication of Consistently Strict Phosphate Control for Coronary and Valvular Calcification in Incident Patients Undergoing Hemodialysis

AIMS

Serum phosphate control is crucial for the progression of vascular and valvular calcifications. Strict phosphate control is recently suggested; however, there is a lack of convincing evidence. Therefore, we explored the effects of strict phosphate control on vascular and valvular calcifications in incident patients undergoing hemodialysis.

METHODS

A total of 64 patients undergoing hemodialysis from our previous randomized controlled trial were included in this study. Coronary artery calcification score (CACS) and cardiac valvular calcification score (CVCS) were evaluated using computed tomography and ultrasound cardiography at baseline and 18 months after the initiation of hemodialysis. The absolute changes in CACS (ΔCACS) and CVCS (ΔCVCS) and the percent change in CACS (%ΔCACS) and CVCS (%ΔCVCS) were calculated. Serum phosphate level was measured at 6, 12, and 18 months after the initiation of hemodialysis. Moreover, phosphate control status was evaluated using the area under the curve (AUC) by the amount of time spent with a serum phosphate level of ≥ 4.5 mg/dL and the extent to which this threshold exceeded over the observation period.

RESULTS

ΔCACS, %ΔCACS, ΔCVCS, and %ΔCVCS were significantly lower in the low AUC group than in the high AUC group. ΔCACS and %ΔCACS were also significantly lower. ΔCVCS and %ΔCVCS tended to be lower in patients whose serum phosphate level never exceeded 4.5 mg/dL than in those whose serum phosphate level continuously exceeded 4.5 mg/dL. AUC significantly correlated with ΔCACS and ΔCVCS.

CONCLUSION

Consistently strict phosphate control may slow the progression of coronary and valvular calcifications in incident patients undergoing hemodialysis.

Kidney function, bone-mineral metabolism markers, and calcification of coronary arteries, aorta, and cardiac valves in older adults

BACKGROUND AND AIMS

The contribution of kidney dysfunction, especially at mild-to-moderate stages, and bone-mineral metabolism (BMM) markers to vascular calcification remains controversial or unclear. We comprehensively evaluated the association of kidney and BMM markers with coronary artery calcification (CAC) and extra-coronary calcification (ECC).

METHODS

In 1931 ARIC participants (age 73-95 years) without coronary heart disease at visit 7 (2018-19), we investigated the associations of estimated glomerular filtration rate (eGFR) (with creatinine, cystatin C, and both) and five serum BMM markers (calcium, fibroblast growth factor 23, magnesium, parathyroid hormone, and phosphorus) with high CAC and ECC (sex-race specific ≥75th vs. <75th percentile Agatston score) or any vs. zero CAC and ECC using multivariable logistic regression. For eGFR and BMM markers, we took their weighted cumulative averages from visit 1 (1987-89) to visit 5 (2011-13).

RESULTS

Lower eGFR, regardless of equations used, was not robustly associated with high CAC or ECC. Among BMM markers, only higher phosphorus levels, even within the normal range, showed robust associations with high CAC (only when modeled continuously) and ECC, independently of kidney function (e.g., odds ratio 1.94 [95%CI 1.38-2.73] for high aortic valve calcification, in the highest vs. lowest quartile). Results were generally consistent when analyzing any CAC or ECC, although cystatin C-based eGFR <60 mL/min/1.73 m2 became significantly associated with mitral valve calcification (odds ratio 1.69 [1.10-2.60]).

CONCLUSIONS

Among kidney and BMM measures tested, only serum phosphorus demonstrated robust associations with both CAC and ECC, supporting a key role of phosphorus in the pathophysiology of vascular calcification.

Vitamin D, parathyroid hormone, glucose metabolism and incident diabetes in the multiethnic study of atherosclerosis

INTRODUCTION

Higher concentrations of serum 25-hydroxyvitamin D (25(OH)D) and lower concentrations of parathyroid hormone (PTH) are associated with lower insulin resistance and incident diabetes in non-Hispanic White and Hispanic Americans. Results are mixed in other populations, with no observational studies in a large multiethnic cohort. The association of serum 25(OH)D with diabetes may vary by adiposity level.

RESEARCH DESIGN AND METHODS

Among 5611 participants in the Multi-Ethnic Study of Atherosclerosis without diabetes at baseline, cross-sectional associations of serum 25(OH)D with homeostasis model assessment of insulin resistance (HOMA-IR) and HOMA-β were examined using linear regressions. The association of 25(OH)D with incident diabetes over 9 years was examined using Cox proportional hazard regression.

RESULTS

Black Americans had the highest proportion of individuals with 25(OH)D<20 ng/mL (61%) and White Americans had the least (17%). Serum 25(OH)D was inversely associated with HOMA-IR in fully adjusted models (-0.34% difference in HOMA-IR per ng/mL higher 25(OH)D, p<0.0001). Longitudinally, a 1 ng/mL higher serum 25(OH)D was associated with 2% lower risk of incident diabetes (HR 0.982, CI 0.974 to 0.991), and a 1 pg/mL higher serum PTH was associated with 1% higher risk of incident diabetes (HR 1.007, CI 1.004 to 1.010), both prior to adjustment for waist circumference. After adjusting for waist circumference, a 1 ng/mL higher 25(OH)D was associated with 1% lower risk of incident diabetes (HR 0.991, CI 0.983 to 1.000). The magnitude of association of serum 25(OH)D with incident diabetes was largest at lower waist circumference (p for interaction=0.025). There was no heterogeneity by race/ethnicity (p=0.317).

CONCLUSIONS

Serum 25(OH)D is inversely associated with insulin resistance and incident diabetes in a diverse cohort, including non-Hispanic White, Black, Hispanic and Chinese Americans. Future research should explore mechanisms for the interaction between serum 25(OH)D and adiposity in this relationship.

Association of serum levels of calcium, phosphate, and vitamin D with risk of developing aortic stenosis: the UK Biobank cohort

AIMS

This study was aimed to investigate the associations of serum calcium, phosphate, and vitamin D levels with the risk of developing aortic stenosis (AS).

METHODS AND RESULTS

We included 296 415 participants who were free of prior diagnosis of any valvular heart disease from the UK Biobank. Serum levels of phosphate, calcium, and vitamin D were measured. Incidental AS was determined by the records of hospital data. Cox regression was used to examine the association of serum mineral levels with incidental AS after adjustment for potential confounders. The mean age was 56.4 years (SD 8.14) and 53.3% of participants were women. During an average follow-up of 8.1 years, 1232 individuals developed AS. After adjustment, each 0.5-unit increase in serum phosphate level was associated with a 50% increase of AS risk (hazard ratio 1.50, 95% confidence interval 1.26-1.80). We observed no association of serum calcium and vitamin D levels with AS.

CONCLUSION

Increased serum phosphate level, but not calcium or vitamin D, was associated with a higher risk of incident AS, this association did not differed substantially between patients with and without decreased kidney function. This finding implied that phosphate may be a potential interventional target for AS.

Association of ambulatory blood pressure with aortic valve and coronary artery calcification

OBJECTIVE

We aimed to investigate the effect of ambulatory blood pressure (BP) on aortic valve calcification (AVC) and coronary artery calcification (CAC), which are subclinical atherosclerotic diseases.

METHODS

In this population-based, cross-sectional study, we assessed office BP, mean ambulatory BP (24-h, awake, and asleep), and variability of ambulatory BP, as determined by the coefficient of variation (awake and asleep). AVC and CAC were quantified using an Agatston score (>0) based on computed tomography scanning. We calculated relative risks (RRs) and 95% confidence intervals (CIs) with a 1-standard deviation increment in each BP index for the presence of AVC and CAC using a multivariate-adjusted Poisson regression with robust error variance.

RESULTS

Of 483 participants (mean age: 66.8 years), 154 (31.9%) and 310 (64.2%) had AVC and CAC, respectively. The presence of AVC was associated with office systolic BP (SBP; RR, 1.15; 95% CI, 1.03-1.28), awake diastolic BP (DBP) variability (RR, 1.12; 95% CI, 1.01-1.25), and asleep SBP variability (RR, 1.14; 95% CI, 1.03-1.27). The presence of CAC was associated with office SBP (RR, 1.08; 95% CI, 1.01-1.15), mean 24-h SBP (RR, 1.10; 95% CI, 1.04-1.16), mean awake SBP (RR, 1.11; 95% CI, 1.04-1.17), mean asleep SBP (RR, 1.07; 95% CI, 1.01-1.13), and asleep SBP variability (RR, 1.07; 95% CI, 1.01-1.13).

CONCLUSION

These findings highlight the association of ambulatory BP indices with both AVC and CAC, but with different effects on their presences.

Hyperphosphatemia is associated with cardiac valve calcification in chronic hypoparathyroidism

PURPOSE

To evaluate the association between metabolic abnormalities and cardiovascular risk factors in patients with chronic hypoparathyroidism (HPP).

PATIENTS AND METHODS

Patients 18 years and older, glomerular filtration > 30 mL/min/1.73 m² and no documented coronary artery disease were selected. Serum calcium, phosphorus, glucose, lipids, PTH, 25(OH)D and FGF23 were measured. Cardiovascular risk was estimated by the European Society of Cardiology (ESC) calculator. Transthoracic echocardiogram and carotid ultrasound were performed to detect carotid plaques (CP), carotid intima-media thickness (IMT), cardiac valve calcification (CVC), and left ventricular hypertrophy (LVH).

RESULTS

Thirty-seven patients (94.6% female), aged 56.0 ± 13.5 years and HPP duration 7.0 (4.0; 11.3) years, were included. Fifteen were classified as low cardiovascular risk, 9 as intermediate risk, 9 as high risk and none as very high risk. The prevalence of CP, CVC and LVH was 24.3%, 24.3% and 13.5%, respectively. IMT values were within normal ranges in all cohort. FGF23 were not associated with CP, IMT, CVC or LVH. After logistic regression, phosphorus was the only significant metabolic variable impacting CVC in univariate analysis (OR 2.795; 95% CI 1.132-6.905; p = 0.026), as well as in the multivariate analysis (OR 3.572; 95% CI 1.094-11.665; p = 0.035). Analysis by ROC curve showed serum phosphorus > 5.05 mg/dL (AUC 0.748; CI 0.584-0.877; p = 0.05) as the best cutoff point associated with valve heart calcification (sensitivity 78%; negative predictive value 91.3%).

CONCLUSION

Hyperphosphatemia was associated with CVC in HPP patients. Further studies are needed to investigate whether the control of hyperphosphatemia may reduce cardiovascular risk in this population.

Sex Differences in Factors Associated With Progression of Aortic Valve Calcification in the General Population

BACKGROUND

Guidelines recommend measurement of the aortic valve calcification (AVC) score to help differentiate between severe and nonsevere aortic stenosis, but a paucity exists in data about AVC in the general population. The aim of this study was to describe the natural history of AVC progression in the general population and to identify potential sex differences in factors associated with this progression rate.

METHODS

Noncontrast cardiac computed tomography was performed in 1298 randomly selected women and men aged 65 to 74 years who participated in the DANCAVAS trial (Danish Cardiovascular Screening). Participants were invited to attend a reexamination after 4 years. The AVC score was measured at the computed tomography, and AVC progression (ΔAVC) was defined as the difference between AVC scores at baseline and follow-up. Multivariable regression analyses were performed to identify factors associated with ΔAVC.

RESULTS

Among the 1298 invited citizens, 823 accepted to participate in the follow-up examination. The mean age at follow-up was 73 years. Men had significantly higher AVC scores at baseline (median AVC score 13 Agatston Units [AU; interquartile range, 0-94 AU] versus 1 AU [interquartile range, 0-22 AU], P<0.001) and a higher ΔAVC (median 26 AU [interquartile range, 0-101 AU] versus 4 AU [interquartile range, 0-37 AU], P<0.001) than women. In the fully adjusted model, the most important factor associated with ΔAVC was the baseline AVC score. However, hypertension was associated with ΔAVC in women (incidence rate ratios, 1.58 [95% CI, 1.06-2.34], P=0.024) but not in men, whereas dyslipidemia was associated with ΔAVC in men (incidence rate ratio: 1.66 [95% CI, 1.18-2.34], P=0.004) but not in women.

CONCLUSIONS

The magnitude of the AVC score was the most important marker of AVC progression. However, sex differences were significant; hence, dyslipidemia was associated with AVC progression only among men; hypertension with AVC progression only among women. Registration: URL: https://www.isrctn.com; Unique identifier: ISRCTN12157806.

Risk Markers for Limited Coronary Artery Calcium in Persons With Significant Aortic Valve Calcium (From the Multi-ethnic Study of Atherosclerosis)

The early stages of aortic valve calcification (AVC) and coronary artery calcification (CAC) include shared ASCVD risk factors, yet there is considerable heterogeneity between the burden of AVC, and CAC. We sought to identify the markers associated with limited CAC among persons with significant AVC. There were 325 participants from the Multi-Ethnic Study of Atherosclerosis without clinical ASCVD and with AVC ≥100 Agatston units (AU) at Visit 1. Multivariable-adjusted prevalence ratios for limited CAC (0 to 99 AU) were calculated using modified Poisson regression. Participants had a mean age of 72.1 years, median AVC score of 209, and 34% were women. A total of 133 (41%) participants had CAC <100, of whom 46/133 had CAC = 0. Younger age (PR = 1.40, 95% CI: 1.22 to 1.62, per 10-years), female gender (PR = 1.68, 95% CI: 1.28 to 2.20), and low 10-year ASCVD risk (PR = 2.30, 95% CI: 1.85 to 2.85) were most strongly associated with limited CAC. Neither a normal lipoprotein(a) nor normal measures of inflammation were significantly associated with limited CAC. Lower serum phosphate (PR = 1.15, 95% CI: 1.01 to 1.31; per 0.5 mg/dl lower) and calcium-phosphate product (PR = 1.16, 95% CI: 1.02 to 1.34; per SD lower) were associated with an approximately 15% higher prevalence of limited CAC. In conclusion, more than 40% of persons with significant AVC had CAC. Beyond traditional risk factors, lower serum phosphate, and lower calcium-phosphate product were associated with a higher prevalence of limited CAC.

Serum phosphate and chronic kidney and cardiovascular disease: Phosphorus potential implications in general population

It has already been established that in end-stage renal disease, hyperphosphatemia causes soft tissue calcification including vascular calcifications. It has also been supported that there is a connection between increased serum phosphate and morbidity in subjects, who suffer from renal disease. However, studies in these populations conferred mixed results. Several warnings are included in the role of serum phosphorus on cardiovascular disease in normal populations. Homeostasis of serum phosphate is obtained by the cooperation between regulatory hormones, cellular receptors and bone metabolic factors. There is the probability that one or more phosphate regulatory factors, rather than phosphate directly, may be responsible for observed associations with calcification and cardiovascular events in normal populations. Experimental studies have shown that the restriction of dietary phosphate prevents the progression of kidney dysfunction, although high dietary phosphate aggravates the renal function. In the current review, we discuss the role of serum phosphorus on progression of renal dysfunction and cardiovascular outcomes in chronic kidney disease patients and its involvement in important health risks in the general population.

Gut Microbiome, Functional Food, Atherosclerosis, and Vascular Calcifications-Is There a Missing Link?

The gut microbiome is represented by the genome of all microorganisms (symbiotic, potential pathogens, or pathogens) residing in the intestine. These ecological communities are involved in almost all metabolic diseases and cardiovascular diseases are not excluded. Atherosclerosis, with a continuously increasing incidence in recent years, is the leading cause of coronary heart disease and stroke by plaque rupture and intraplaque hemorrhage. Vascular calcification, a process very much alike with osteogenesis, is considered to be a marker of advanced atherosclerosis. New evidence, suggesting the role of dietary intake influence on the diversity of the gut microbiome in the development of vascular calcifications, is highly debated. Gut microbiota can metabolize choline, phosphatidylcholine, and L-carnitine and produce vasculotoxic metabolites, such as trimethylamine-N-oxide (TMAO), a proatherogenic metabolite. This review article aims to discuss the latest research about how probiotics and the correction of diet is impacting the gut microbiota and its metabolites in the atherosclerotic process and vascular calcification. Further studies could create the premises for interventions in the microbiome as future primary tools in the prevention of atherosclerotic plaque and vascular calcifications.

Cross-sectional study of aortic valve calcification and cardiovascular risk factors in older Danish men

OBJECTIVE

Aortic valve calcification (AVC) and coronary artery calcification (CAC) are predictors of cardiovascular disease (CVD), presumably sharing risk factors. Our objectives were to determine the prevalence and extent of AVC in a large population of men aged 60-74 years and to assess the association between AVC and cardiovascular risk factors including CAC and biomarkers.

METHODS

Participants from the DANish CArdioVAscular Screening and intervention trial (DANCAVAS) with AVC and CAC scores and without previous valve replacement were included in the study. Calcification scores were calculated on non-contrast CT scans. Cardiovascular risk factors were self-reported, measured or both, and further explored using descriptive and regression analysis for AVC association.

RESULTS

14 073 men aged 60-74 years were included. The AVC scores ranged from 0 to 9067 AU, with a median AVC of 6 AU (IQR 0-82). In 8156 individuals (58.0%), the AVC score was >0 and 215 (1.5%) had an AVC score ≥1200. In the regression analysis, all cardiovascular risk factors were associated with AVC; however, after inclusion of CAC ≥400, only age (ratio of expected counts (REC) 1.07 (95% CI 1.06 to 1.09)), hypertension (REC 1.24 (95% CI 1.09 to 1.41)), obesity (REC 1.34 (95% CI 1.20 to 1.50)), known CVD (REC 1.16 (95% CI 1.03 to 1.31)) and serum phosphate (REC 2.25 (95% CI 1.66 to 3.10) remained significantly associated, while smoking, diabetes, hyperlipidaemia, estimated glomerular filtration rate and serum calcium were not.

CONCLUSIONS

AVC was prevalent in the general population of men aged 60-74 years and was significantly associated with all modifiable cardiovascular risk factors, but only selectively after adjustment for CAC ≥400 AU.

TRIAL REGISTRATION NUMBER

NCT03946410 and ISRCTN12157806.

Lipoprotein Particle Profiles Compared With Standard Lipids in the Association With Subclinical Aortic Valve Calcification in Apparently Healthy Japanese Men

BACKGROUND

Risk factors for atherosclerotic disease including dyslipidemia have been shown to be associated with aortic valve calcification (AVC). Nuclear magnetic resonance (NMR)-measured lipoprotein particles, low-density and high-density lipoprotein particles (LDL-p, HDL-p) in particular, have emerged as novel markers of atherosclerotic disease; however, whether NMR-measured particles are associated with AVC remains to be determined. This study aimed to examine the association between NMR-based lipoprotein particle measurements and standard lipids with AVC. The primary variables of interest were LDL-p (nmol/L), HDL-p (μmol/L), LDL-cholesterol, and HDL-cholesterol (both in mg/dL).

METHODS AND RESULTS

A community-based random sample of Japanese men aged 40-79 years examined in 2006-2008, in Shiga, Japan was studied. Presence of AVC was defined as an Agatston score >0. Lipoprotein particles were measured using NMR spectroscopy. In the main analysis, multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for the prevalence of AVC across the higher quartiles of lipids in reference to the lowest ones were obtained. Of 874 participants analyzed, 153 men had AVC. Multivariable-adjusted ORs of prevalent AVC for the highest vs. the lowest quartile were significantly elevated for LDL-p (OR, 2.20; 95% CI: 1.23-3.93) and LDL-cholesterol (OR, 2.16; 95% CI: 1.23-3.78). In contrast, neither HDL-p nor HDL-cholesterol was associated with AVC.

CONCLUSIONS

The association of prevalent AVC with NMR-based LDL-p was comparable to that with LDL-cholesterol.

Early Contributors to Healthy Arterial Aging Versus Premature Atherosclerosis in Young Adults: The Bogalusa Heart Study

Background

Early identification of healthy arterial aging versus premature atherosclerosis is important for optimal atherosclerotic cardiovascular disease risk stratification and prevention. We sought to identify predictors for the long‐term absence of carotid plaque among young adults.

Methods and Results

We included 508 participants from the Bogalusa Heart Study without clinical atherosclerotic cardiovascular disease who were free of carotid plaque at baseline (2001–2002) and underwent ultrasound imaging at follow‐up (2013–2016). Modified Poisson regression estimated the persistent absence of plaque over 12.8 years. Participants were on average age 36.2 years at baseline, 64% were women, and 29% were Black. Although nearly all participants (97%) had a 10‐year atherosclerotic cardiovascular disease risk <7.5%, there were 162 people (32%) who developed premature atherosclerosis. Aside from younger age (risk ratio [RR], 1.21; 95% CI, 1.07–1.36, per 10 years) and a total cholesterol/high‐density lipoprotein cholesterol ratio <3.5 (RR, 1.15; 95% CI, 1.01–1.30), normal values of traditional risk factors did not predict long‐term absence of plaque. Independent from traditional markers including glomerular filtration rate, serum calcium‐phosphate product (RR, 1.07; 95% CI, 1.01–1.14, per 1‐SD lower), phosphate (RR, 1.15; 95% CI, 1.03–1.29, per 1 mg/dL lower), and dietary sodium <2300 mg/day (RR, 1.20; 95% CI, 1.02–1.41) were significantly associated with the non‐development of plaque.

Conclusions

Nearly one third of young adults with a low burden of traditional risk factors developed premature atherosclerosis. Beyond younger age and an ideal lipoprotein profile, lower calcium‐phosphate homeostasis and low sodium intake were associated with long‐term absence of carotid plaque. These results suggest that dietary and intrinsic minerals are early contributors to the development of arterial aging phenotypes.

Serum levels of C-terminal FGF23 (cFGF23) are associated with 1-year-mortality in patients undergoing transcatheter aortic valve replacement (TAVR)

INTRODUCTION

Serum levels of FGF23 have been associated with adverse outcomes in cardiovascular diseases in patients with and without impaired renal function. Hence, this study aimed to explore the prognostic relevance of intact FGF23 (iFGF23) and its derivate C-terminal FGF23 (cFGF23) in patients undergoing transcatheter aortic valve replacement (TAVR) with regard to renal function.

METHODS

A total of 274 patients undergoing transfemoral TAVR were enrolled in this study. Blood samples were obtained preinterventionally and analyzed for iFGF23 and cFGF23 by means of enzyme linked immunosorbent assay (ELISA). Follow-up was obtained for 12 months.

RESULTS

Serum levels of cFGF23 and iFGF23 both correlated positively with serum creatinine and inversely with estimated glomerular filtration rate (eGFR). Cox regression analysis revealed a significant association of cFGF23 with 1-year-mortality in patients with eGFR ≥45ml/min/1.73m², but not in patients with an eGFR <45ml/min/1.73m². A cut-off was calculated for cFGF23 (6.82 pmol/l) and patients with eGFR ≥45ml/min/1.73m² were retrospectively divided into two groups (above/below cut-off). Patients above the cut-off had a significantly worse 1-year-mortality than patients below the cut-off (33.3% vs. 19.6%; OR 2.05 (95%CI 1.03-4.07), p= 0.038). The association of cFGF23 with 1-year-mortality in patients with eGFR ≥45ml/min/1.73m² remained statistically significant even after correction for possible confounders in a multivariate Cox regression analysis.

CONCLUSION

cFGF23 could be an individual risk factor for mortality in patients undergoing TAVR with an eGFR ≥45ml/min/1.73m².

Association of aortic valve calcification with carotid artery lesions and peripheral artery disease in patients with chronic kidney disease: a cross-sectional study

Background

Patients with chronic kidney disease (CKD) reportedly have a high prevalence of aortic valve calcification (AVC). In population-based studies, AVC is considered a manifestation of systemic atherosclerosis. The association of AVC with atherosclerotic lesions has not been fully investigated in predialysis patients. The present study was performed to determine whether carotid artery lesions and peripheral artery disease (PAD) are associated with AVC in patients with CKD not on dialysis.

Methods

In total, 749 patients were included in this cross-sectional study. AVC was evaluated using echocardiography. Carotid artery lesions including carotid artery plaque (CAP) and PAD were simultaneously examined in each patient. A logistic regression analysis was applied to determine the factors associated with AVC.

Results

AVC, CAP, and PAD were found in 201, 583, and 123 patients, respectively. In the multivariable analyses adjusted for covariates including the estimated glomerular filtration rate and makers of mineral metabolism (serum calcium, serum phosphorus, parathyroid hormone, 1,25-dihydroxyvitamin D, and fibroblast growth factor 23), AVC was significantly associated with the presence of CAP [odds ratio (OR), 3.37; 95% confidence interval (CI), 1.43–7.95], the presence of PAD (OR, 1.76; 95% CI, 1.10–2.81), the CAP score (per 1.0-point increase) (OR, 1.06; 95% CI, 1.02–1.11), and the ankle-brachial blood pressure index (per 0.1-point increase) (OR, 0.83; 95% CI, 0.72–0.95).

Conclusions

AVC was associated with atherosclerotic lesions independent of kidney function and mineral metabolism. We consider that this association between AVC and atherosclerosis might reflect the burden of shared atherosclerotic risk factors.

Identification of key genes and pathways in calcific aortic valve disease by bioinformatics analysis

Background

Calcific aortic valve disease (CAVD) is the most common type of valvular heart disease in the elderly. This study is aimed to explore molecular mechanism of CAVD via bioinformatics analysis.

Methods

The gene expression profiles of GSE51472 (including 5 normal aortic valve and 5 calcified aortic valve) and GSE83453 (including 8 normal aortic valve and 19 calcified aortic valve) were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were screened using the MetaDE package in R software. Functional and pathway enrichment analysis were performed based on Gene ontology (GO) and KEGG pathway database. Then, STRING database, Cytoscape and MCODE were applied to construct the protein-protein interaction (PPI) network and screen hub genes. Pathway enrichment analysis was further performed for hub genes and gene clusters identified via module analysis.

Results

A total of 107 DEGs were identified in CAVD (53 up-regulated genes, and 54 down-regulated genes), and they were mainly enriched in the terms of immune response, extracellular matrix organization, leukocyte transendothelial migration, cell adhesion molecules (CAMs), and fatty acid metabolism. Five hub genes including VCAM1, MMP9, ITGB2, RAC2, and vWF were identified via PPI network, which were mainly enriched in terms of leukocyte transendothelial migration and cell adhesion. An independently down-regulated protein cluster containing ALDH2, HIBCH, ACADVL, ECHDC2, VAT1L, and MAOA was also identified via PPI network.

Conclusions

The present study identified VCAM1, MMP9, ITGB2, RAC2, vWF and ALDH2 as key genes in the progression of CAVD. Immune cells infiltration might play a key role in the progression of CAVD, while ALDH2-mediated detoxification effect might play a protective role in CAVD. Further studies are needed to elucidate the pathogenesis of CAVD.

Kidney Dysfunction and the Risk of Developing Aortic Stenosis

BACKGROUND

Chronic kidney disease (CKD) and aortic stenosis (AS) share many risk factors.

OBJECTIVES

This study sought to evaluate whether kidney dysfunction is associated with the development of AS in the community.

METHODS

The study included 1,121,875 Stockholm citizens without a prior diagnosis of AS from the SCREAM (Stockholm CREAtinine Measurements) project. Estimated glomerular filtration rate (eGFR) (ml/min/1.73 m²) was calculated from serum creatinine. AS incidence during follow-up was ascertained by clinical diagnostic codes. The association between eGFR and AS incidence was estimated with multivariable Cox proportional hazards models. Sensitivity analyses included analysis of possible reverse causation bias by excluding the first 6 months to 2 years after enrollment and excluding individuals with comorbid heart failure.

RESULTS

The median age was 50 years (interquartile range [IQR]: 36 to 64 years), and 54% of participants were women. Median eGFR was 96 ml/min/1.73 m² (IQR: 82 to 109 ml/min/1.73 m²), and 66,949 (6.0%) participants had CKD (eGFR <60 ml/min/1.73 m²). During a median follow-up of 5.1 years (IQR: 3.3 to 6.1 years), 5,858 (0.5%) individuals developed AS (incidence rate [IR] 1.13/1,000 person-years). Compared with eGFR >90 (IR 0.34/1,000 person-years), lower eGFR strata were associated with higher hazards of AS: eGFR 60 to 90 ml/min/1.73 m²; IR: 1.88; hazard ratio (HR): 1.14; 95% confidence interval (CI): 1.05 to 1.25; eGFR 45 to 59 ml/min/1.73 m²; IR: 4.61; HR: 1.17; 95% CI: 1.05 to 1.30; eGFR 30 to 44 ml/min/1.73 m²; IR: 6.62; HR: 1.22; 95% CI: 1.07 to 1.39; and eGFR 30 ml/min/1.73 m²; IR: 8.27; HR: 1.56; 95% CI: 1.29 to 1.87. Sensitivity analysis attenuated only slightly the magnitude of the association; individuals with eGFR ≤44 ml/min/1.73 m² remained at an approximate 20% risk of AS both when excluding events within the 2 years after baseline (HR: 1.22; 95% CI: 1.06 to 1.42) and when excluding participants with heart failure (HR: 1.20; 95% CI: 1.03 to 1.39).

CONCLUSIONS

CKD, even in moderate to severe stages, is associated with an increased risk of AS.

Re-evaluation of phosphoric acid-phosphates - di-, tri- and polyphosphates (E 338-341, E 343, E 450-452) as food additives and the safety of proposed extension of use

The Panel on Food Additives and Flavourings added to Food (FAF) provided a scientific opinion re-evaluating the safety of phosphates (E 338-341, E 343, E 450-452) as food additives. The Panel considered that adequate exposure and toxicity data were available. Phosphates are authorised food additives in the EU in accordance with Annex II and III to Regulation (EC) No 1333/2008. Exposure to phosphates from the whole diet was estimated using mainly analytical data. The values ranged from 251 mg P/person per day in infants to 1,625 mg P/person per day for adults, and the high exposure (95th percentile) from 331 mg P/person per day in infants to 2,728 mg P/person per day for adults. Phosphate is essential for all living organisms, is absorbed at 80-90% as free orthophosphate excreted via the kidney. The Panel considered phosphates to be of low acute oral toxicity and there is no concern with respect to genotoxicity and carcinogenicity. No effects were reported in developmental toxicity studies. The Panel derived a group acceptable daily intake (ADI) for phosphates expressed as phosphorus of 40 mg/kg body weight (bw) per day and concluded that this ADI is protective for the human population. The Panel noted that in the estimated exposure scenario based on analytical data exposure estimates exceeded the proposed ADI for infants, toddlers and other children at the mean level, and for infants, toddlers, children and adolescents at the 95th percentile. The Panel also noted that phosphates exposure by food supplements exceeds the proposed ADI. The Panel concluded that the available data did not give rise to safety concerns in infants below 16 weeks of age consuming formula and food for medical purposes.

Development of calcific aortic valve disease: Do we know enough for new clinical trials?

Calcific aortic valve disease (CAVD), previously thought to represent a passive degeneration of the valvular extracellular matrix (VECM), is now regarded as an intricate multistage disorder with sequential yet intertangled and interacting underlying processes. Endothelial dysfunction and injury, initiated by disturbed blood flow and metabolic disorders, lead to the deposition of low-density lipoprotein cholesterol in the VECM further provoking macrophage infiltration, oxidative stress, and release of pro-inflammatory cytokines. Such changes in the valvular homeostasis induce differentiation of normally quiescent valvular interstitial cells (VICs) into synthetically active myofibroblasts producing excessive quantities of the VECM and proteins responsible for its remodeling. As a result of constantly ongoing degradation and re-deposition, VECM becomes disorganised and rigid, additionally potentiating myofibroblastic differentiation of VICs and worsening adaptation of the valve to the blood flow. Moreover, disrupted and excessively vascularised VECM is susceptible to the dystrophic calcification caused by calcium and phosphate precipitating on damaged collagen fibers and concurrently accompanied by osteogenic differentiation of VICs. Being combined, passive calcification and biomineralisation synergistically induce ossification of the aortic valve ultimately resulting in its mechanical incompetence requiring surgical replacement. Unfortunately, multiple attempts have failed to find an efficient conservative treatment of CAVD; however, therapeutic regimens and clinical settings have also been far from the optimal. In this review, we focused on interactions and transitions between aforementioned mechanisms demarcating ascending stages of CAVD, suggesting a predisposing condition (bicuspid aortic valve) and drug combination (lipid-lowering drugs combined with angiotensin II antagonists and cytokine inhibitors) for the further testing in both preclinical and clinical trials.

Biomarkers of mineral metabolism and progression of aortic valve and mitral annular calcification: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

Previous research has implicated dysregulation of phosphate metabolism and calcium-phosphate solubilization in cardiovascular calcification, but epidemiologic studies evaluating longitudinal associations with valvular or annular calcification by computed tomography (CT), a highly sensitive imaging modality, are lacking. Our primary aim was to investigate the associations of mineral biomarkers with incidence and progression of aortic valve calcification (AVC) and mitral annular calcification (MAC).

METHODS

We evaluated the associations of serum FGF-23 (n = 6547 participants), phosphate (n = 6547), and fetuin-A (n = 2550) measured at baseline in the community-based Multi-Ethnic Study of Atherosclerosis with AVC and MAC on CT performed at baseline and at a median of 2.4 (1.6, 3.1) years later. We used linear mixed-effects models to account simultaneously for prevalence, incidence and progression of AVC and MAC.

RESULTS

After adjustment for demographic and clinical characteristics, a significant association was documented for FGF-23 with accelerated annual progression of MAC (2.83 Agatston units (AU), 95% CI = 0.49, 5.17 AU, per standard deviation (18.46 pg/mL) of FGF-23), but this was not seen for phosphate or fetuin-A. None of these biomarkers was associated with accelerated annual progression of AVC.

CONCLUSIONS

This study provides evidence relating serum FGF-23 to accelerated annual MAC progression. Whether this mineral regulator is a risk marker or is involved in pathogenesis merits further investigation.

Risk factors for valvular calcification

PURPOSE OF REVIEW

Recent literature is examined to identify established and emerging risk factors for valvular calcification, specifically calcific aortic valve disease and mitral annular calcification.

RECENT FINDINGS

Strong evidence implicates older age, male sex, cigarette smoking, elevated blood pressure, dyslipidaemia, adiposity, and mineral metabolism as risk factors for calcific aortic valve disease. Emerging evidence suggests family history and lipoprotein(a) are additional risk factors. Recently, large-scale genome-wide analyses have identified robust associations for LPA, PALMD, and TEX41 with aortic stenosis. Factors predisposing to mitral annular calcification are less well characterized. Older age, cigarette smoking, increased BMI, kidney dysfunction, and elevated triglycerides are associated with greater risk of mitral annular calcification, but conflicting evidence exists for sex and C-reactive protein.

SUMMARY

Established and emerging risk factors for calcific aortic valve disease, including some that overlap with atherosclerosis, may represent targets for pharmacological intervention. Mitral annular calcification is comparatively less well understood though some atherosclerosis risk factors do appear to increase risk.

Serum magnesium, phosphorus, and calcium levels and subclinical calcific aortic valve disease: A population-based study

BACKGROUND AND AIMS

Calcific aortic valve disease (CAVD) is the most common valve disease. Although micronutrients are known to contribute to cardiovascular disease, the relationship with CAVD remains poorly evaluated. We examined the association of serum levels of magnesium, phosphorus, and calcium with prevalence, incidence, and progression of aortic valve calcification (AVC).

METHODS

We conducted a prospective study in a population-based sample of Japanese men aged 40-79 years without known cardiovascular disease and chronic kidney disease at baseline, and quantified AVC from serial computed tomographic images with the Agatston method.

RESULTS

Of 938 participants at baseline (mean age, 63.7 ± 9.9 years), AVC prevalence was observed in 173 (18.4%). Of 596 participants without baseline AVC at follow-up (median duration, 5.1 years), AVC incidence was observed in 138 (23.2%). After adjustment for demographics, behaviors and cardiovascular risk factors, relative risks (95% confidence intervals) in the highest versus lowest categories of serum magnesium, phosphorus, and calcium were 0.62 (0.44-0.86), 1.45 (1.02-2.04), and 1.43 (0.95-2.15), respectively, for AVC prevalence and 0.62 (0.42-0.92), 1.93 (1.28-2.91), and 1.09 (0.77-1.55), respectively, for AVC incidence. Their linear trends of serum magnesium and phosphorus were also all statistically significant. Of 131 participants with baseline AVC, there was no association of any serum micronutrients with AVC progression.

CONCLUSIONS

Serum magnesium was inversely associated, while serum phosphorus was positively associated with AVC prevalence and incidence, suggesting that these serum micronutrients may be potential candidates for risk prediction or prevention of CAVD, and warranting further studies.

Serum Phosphate and Retinal Microvascular Changes: The Multi-Ethnic Study of Atherosclerosis and the Beaver Dam Eye Study

PURPOSE

Higher levels of serum phosphate are strongly linked to increased risk of cardiovascular disease and therapies aimed to lower serum phosphate are employed in the management of patients with chronic kidney disease (CKD). Data are limited, however, on serum phosphate as a risk factor for microvascular disease in community-based populations. It is important to determine the impact of novel risk factors, such as phosphate, on the microvasculature.

METHODS

We conducted a prospective study of 3919 individuals in the Multi-Ethnic Study of Atherosclerosis (MESA) and 3544 individuals in the Beaver Dam Eye Study (BDES) to test the associations of serum phosphate with retinopathy and retinal vessel caliber, and change in retinopathy severity and change in retinal vessel caliber.

RESULTS

Mean (standard deviation) serum phosphate was 3.66 (0.52) mg/dl in the MESA and 3.77 (0.55) mg/dl in the BDES. In multivariable adjusted models, phosphate was significantly associated with prevalent retinopathy in the MESA (Odds Ratio [OR] per 1 mg/dl increase in phosphate, 1.22; Confidence Interval [CI] 1.02-1.47) and the BDES (OR 1.06; CI 1.01-1.11). In stratified analyses, these relationships were even stronger and only seen in individuals with diabetes in both the MESA (OR 1.81; CI 1.30-2.53) and the BDES (OR 1.16; CI 1.05-1.29). Phosphate was not associated with incident or change in retinopathy severity, nor any retinal caliber outcome.

CONCLUSIONS

Among community-living individuals with low prevalence of CKD, higher serum phosphate was associated with prevalent retinopathy in individuals with diabetes. Further longitudinal assessments in patients with diabetes necessitate further investigation.

Effects of serum phosphorus on vascular calcification in a healthy, adult population: A systematic review

Cardiovascular disease has been associated with elevated serum phosphorus levels, which have been associated with cardiovascular mortality. This is commonly seen in the chronic kidney disease (CKD) population where studies have shown that high phosphorus levels cause coronary artery calcification. Although studies have independently associated vascular stiffness and serum phosphorus in those with and without CKD, there are fewer data in individuals without CKD. Therefore, the aim of this systematic review was to analyze whether serum phosphorus levels are associated with cardiovascular calcification in healthy individuals. A systematic review of the literature that was conducted revealed 10 articles, all cross-sectional studies, that met eligibility criteria. These criteria were peer-reviewed studies on a healthy, adult population written in the English language. Studies lacking data on serum phosphorus and measured to assess its association with vascular calcification were excluded. Studies on subjects with CKD, other chronic diseases, or on children were also excluded. Of the 10 studies located, 8 indicated an association between serum phosphorus and vascular calcification. One study did not indicate an association. One study indicated a statistically significant association between serum phosphorus and vascular calcification prevalence, but not incidence. Studies were limited since no randomized controlled trials were available. This systematic review generates gaps in research. Due to considerable amounts of phosphorus additives in the food supply, there may be a connection to dietary phosphorus and vascular calcification. Additionally, phosphorus binders may assist in the prevention of vascular calcification but have not been studied in a healthy population. Further study on both dietary phosphorus restriction and phosphorus binders is needed. While 8 out of 10 cross-sectional studies found an association in this systematic review, the topic of vascular calcification and serum phosphorus needs further study if a cause and effect relationship is to be detected.

Relation of Serum Vitamin D to Risk of Mitral Annular and Aortic Valve Calcium (from the Multi-Ethnic Study of Atherosclerosis)

Serum 25-hydroxyvitamin D [25(OH)D] concentration has been identified as a possible modifiable risk factor for cardiovascular disease (CVD). We hypothesized that serum 25(OH)D concentration would be associated with calcifications of the left-sided heart valves, which are markers of CVD risk. Aortic valve calcium (AVC) and mitral annular calcium (MAC) were quantified from cardiac computed tomography scans performed on 5,530 Multi-Ethnic Study of Atherosclerosis participants at the baseline examination (2000 to 2002) and at a follow-up visit at either Examination 2 (2002 to 2004) or Examination 3 (2004 to 2005). 25(OH)D was measured from serum samples collected at the baseline examination. Using relative risk regression, we evaluated the multivariable-adjusted risk of prevalent and incident AVC and MAC in this ethnically diverse population free of clinical CVD at baseline. The mean age of participants was 62 ± 10 years; 53% were women, 40% white, 26% black, 21% Hispanic, and 12% Chinese. Prevalent AVC and MAC were observed in 12% and 9% of study sample, respectively. There were no significant associations between 25(OH)D and prevalent AVC or MAC. Over a mean follow-up of 2.5 years, 4% developed incident AVC and 5% developed incident MAC. After adjusting for demographic variables, each 10 ng/ml higher serum 25(OH)D was associated with a 15% (relative risk 0.85, 95% confidence interval 0.74 to 0.98) lower risk of incident MAC but not AVC. However, this association was no longer significant after adjusting for lifestyle and CVD risk factors. Results suggest a possible link between serum 25(OH)D and the risk for incident MAC, but future studies with longer follow-up are needed to further test this association.

Biomarkers of Calcific Aortic Valve Disease

Calcific aortic valve disease (CAVD) is a highly prevalent cardiovascular disorder accounting for a rising economic and social burden on aging populations. In spite of continuing study on the pathophysiology of disease, there remain no medical therapies to prevent the progression of CAVD. The discovery of biomarkers represents a potentially complementary approach in stratifying risk and timing of intervention in CAVD and has the advantage of providing insight into causal factors for the disease. Biomarkers have been studied extensively in atherosclerotic cardiovascular disease, with success as additive for clinical and scientific purposes. Similar research in CAVD is less robust; however, the available studies of biomarkers in CAVD show promise for enhanced clinical decision making and identification of causal factors for the disease. This comprehensive review summarizes available established and novel biomarkers in CAVD, their contributions toward an understanding of pathophysiology, their potential clinical utility, and provides an outline to direct future research in the field.

Mineral metabolism and cardiovascular disease in CKD

The mineral bone disorder of CKD, called Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD), has a major role in the etiology and progression of cardiovascular disease in CKD patients. Since the main emphasis in CKD-MBD is on three categories (bone abnormalities, laboratory abnormalities, and vascular calcifications), we have routinely accepted ectopic cardiovascular calcifications as a central risk factor in the pathophysiology of CKD-MBD for cardiac events. However, recent compelling evidence suggests that some CKD-MBD-specific factors other than vascular calcification might contribute to the onset of cardiovascular disease. Most notable is fibroblast growth factor-23 (FGF23), which is thought to be independently associated with cardiac remodeling. Slow progression of cardiac disorders, such as vascular calcification and cardiac remodeling, characterizes cardiac disease due to CKD-MBD. In contrast, fatal arrhythmia may be induced when QT prolongation occurs with CKD-MBD treatment, such as with lower Ca dialysate or the use of calcimimetics. Sudden onset of fatal cardiac events, such as heart failure and sudden cardiac death, due to fatal arrhythmia would be another distinctive phenomenon of CKD-MBD. This may be defined as CKD-MBD-specific cardiac complex syndrome.

Con: Phosphate binders in chronic kidney disease

Phosphate binders are prescribed to chronic kidney disease (CKD) patients based on associations of serum phosphate concentrations with mortality and calcification, experimental evidence for direct calcifying effects of phosphate on vascular smooth muscle tissue and the central importance of phosphate retention in CKD-mineral and bone disorder (CKD-MBD). Current knowledge regarding phosphate metabolism in CKD provides important insight into disease mechanisms and supports future clinical trials of phosphate binders in CKD patients to determine the impact of these medications on clinically relevant outcomes. The risks and benefits of phosphate binders cannot be inferred from association studies of serum phosphate concentrations, which are inconsistent and subject to confounding, animal-experimental data, which are based on conditions that differ from human disease, or physiological arguments, which are limited to known regulatory factors. Many interventions that targeted biochemical pathways suggested by association studies and suspected biological importance have yielded null or harmful results. Clinical trials of phosphate binders are of high clinical and scientific importance to nephrology. Demonstration of reduced rates of clinical disease in such trials could lead to important health benefits for CKD patients, whereas negative results would refocus efforts to understand and treat CKD-MBD. Clinical trials that employ highly practical or 'pragmatic' designs represent an optimal approach for determining the safety and effectiveness of phosphate binders in real-world settings. Absent clinical trial data, observational studies of phosphate binders in large CKD populations could provide important information regarding the benefits, risks and/or unintended side effects of these medications.

Serum phosphate is an independent predictor of the total aortic calcification volume in non-hemodialysis patients undergoing cardiovascular surgery

BACKGROUND

A high serum phosphate level is a well-known risk factor for vascular calcification (VC) in patients on hemodialysis (HD). However, the association between the serum phosphate level and VC in non-HD patients is unclear. Our aim was to assess the impact of serum phosphate level on aortic calcification (AC) volume in non-HD patients undergoing cardiovascular surgery.

METHODS

A total of 117 patients who underwent thoracoabdominal computed tomography as a preoperative general evaluation before cardiovascular surgery were enrolled. The total AC volume was quantified using the volume-rendering method by extracting the area ≥130HU within the entire aorta. The total AC volume index (AC-VI) was estimated as the total AC volume divided by the body surface area.

RESULTS

In the 117 patients (64.7±13.1 years, 39% women), the median total AC-VI was 1.23mL/m(2). The mean estimated glomerular filtration rate (eGFR), adjusted serum calcium levels, and serum phosphate levels were 63.8±19.9mL/min/1.73m(2), 9.1±0.4mg/dL, and 3.6±0.6mg/dL, respectively. When the patients were classified into four quartiles based on their total AC-VI value, the serum phosphate level showed a positive correlation with a probability of being in the highest AC-VI quartile (R(2)=0.0146, p=0.0383) whereas the adjusted serum calcium level did not show a significant correlation (R(2)=0.0040, p=0.2615). A similar relationship between the serum phosphate level, adjusted serum calcium level, and AC-VI was confirmed when the total AC-VI was divided into the thoracic AC-VI and abdominal AC-VI. Multivariate analysis indicated that the serum phosphate level was an independent positive predictor of higher total AC-VI quartiles (β=0.8013, p=0.0160).

CONCLUSIONS

An increase in serum phosphate level was associated with an increased AC burden in non-HD patients undergoing cardiovascular surgery.

A review of the effect of diet on cardiovascular calcification

Cardiovascular (CV) calcification is known as sub-clinical atherosclerosis and is recognised as a predictor of CV events and mortality. As yet there is no treatment for CV calcification and conventional CV risk factors are not consistently correlated, leaving clinicians uncertain as to optimum management for these patients. For this reason, a review of studies investigating diet and serum levels of macro- and micronutrients was carried out. Although there were few human studies of macronutrients, nevertheless transfats and simple sugars should be avoided, while long chain ω-3 fats from oily fish may be protective. Among the micronutrients, an intake of 800 μg/day calcium was beneficial in those without renal disease or hyperparathyroidism, while inorganic phosphorus from food preservatives and colas may induce calcification. A high intake of magnesium (≥380 mg/day) and phylloquinone (500 μg/day) proved protective, as did a serum 25(OH)D concentration of ≥75 nmol/L. Although oxidative damage appears to be a cause of CV calcification, the antioxidant vitamins proved to be largely ineffective, while supplementation of α-tocopherol may induce calcification. Nevertheless other antioxidant compounds (epigallocatechin gallate from green tea and resveratrol from red wine) were protective. Finally, a homocysteine concentration >12 µmol/L was predictive of CV calcification, although a plasma folate concentration of >39.4 nmol/L could both lower homocysteine and protect against calcification. In terms of a dietary programme, these recommendations indicate avoiding sugar and the transfats and preservatives found in processed foods and drinks and adopting a diet high in oily fish and vegetables. The micronutrients magnesium and vitamin K may be worthy of further investigation as a treatment option for CV calcification.

Advances in the treatment of aortic valve disease: is it time for companion diagnostics?

PURPOSE OF REVIEW

Aortic valve disease (AVD) is a growing public health problem, and the pathogenesis underlying AVD is complex. The lack of durable bioprostheses and pharmacologic therapies remain central needs in care. The purpose of this review is to highlight recent clinical studies that impact the care of children with AVD and is to explore ongoing translational research efforts.

RECENT FINDINGS

Clinical studies have evaluated the durability of bioprosthetics and surgical strategies, tested statins during early disease, and identified new predictive biomarkers. Large animal models have demonstrated the effectiveness of a novel bioprosthetic scaffold. Mouse models of latent AVD have advanced our ability to elucidate natural history and perform preclinical studies that test new treatments in the context of early disease.

SUMMARY

Current priorities for AVD patients include identifying new pharmacologic treatments and developing durable bioprostheses. Multidisciplinary efforts are needed that bridge pediatric and adult programs, and bring together different types of expertise and leverage network and consortium resources. As our understanding of the underlying complex genetics is better defined, companion diagnostics may transform future clinical trials and ultimately improve the care of patients with AVD by promoting personalized medicine and early intervention.

Molecular biology of calcific aortic valve disease: towards new pharmacological therapies

Calcific aortic valve disease (CAVD) is a chronic process leading to fibrosis and mineralization of the aortic valve. Investigations in the last several years have emphasized that key underlying molecular processes are involved in the pathogenesis of CAVD. In this regard, the processing of lipids and their retention has been underlined as an important mechanism that triggers inflammation. In turn, inflammation promotes/enhances the mineralization of valve interstitial cells, the main cellular component of the aortic valve. On the other hand, transformation of valve interstitial cells into myofibroblasts and osteoblast-like cells is determined by several signaling pathways having reciprocal cross-talks. In addition, the mineralization of the aortic valve has been shown to rely on ectonucleotidase and purinergic signaling. In this review, the authors have highlighted key molecular underpinnings of CAVD that may have significant relevance for the development of novel pharmaceutical therapies.