Plasma N-terminal pro-B-type natriuretic peptide in the detection of aortic valve stenosis

BACKGROUND

Systolic murmur suggestive of aortic valve origin is a common accidental finding, particularly in the elderly. Usually, it is due to aortic stenosis (AS) or aortic sclerosis (ASc). Currently, echocardiography is used to differentiate AS from ASc. Plasma N-terminal (NT)-prohormone BNP (NT-proBNP) is known to correlate with the severity of AS. We assessed whether NT-proBNP separates AS from ASc.

METHODS

The study population consisted of three groups: AS (n = 87, age 77 ± 7 years), ASc (n = 76, age 72 ± 10 years), and healthy controls (n = 101, age 55 ± 10 years). All subjects underwent transthoracic echocardiography and measurement of plasma NT-proBNP. Patients with diseases known to increase NT-proBNP were excluded.

RESULTS

The crude plasma NT-proBNP (median; IQR) in AS patients (413; 165-1055 ng/l) was significantly higher compared to ASc patients (96; 53-237 ng/l, p < 0.001) and healthy controls (50; 29-76 ng/l, p < 0.001). After adjusting for the confounding factors (age, coronary artery disease, renal function and diastolic blood pressure), plasma NT-proBNP remained significantly higher in AS patients as compared to ASc (p < 0.002) and controls (p < 0.0001). In the receiver-operating characteristic curve for NT-proBNP to identify AS from ASc and controls, the area under the curve was 0.878 with optimal cutoff of 115 ng/l. In addition, using 115 ng/l to separate AS from ASc yielded sensitivity of 0.885, and negative predictive value of 0.808.

CONCLUSIONS

NT-proBNP was sensitive to identify AS and useful to rule out AS in patients with systolic murmur in the left ventricular outflow tract provided the patient does not have coexisting disease known to impact NT-proBNP.

Decreased expression of RPL15 and RPL18 exacerbated the calcification of valve interstitial cells during aortic valve calcification

Calcific aortic valve disease (CAVD) is the most common valvular heart disease, with an increasing prevalence due to an aging population. The pathobiology of CAVD is a multifaceted and actively regulated process, but the detailed mechanisms have not been elucidated. The present study aims to identify the differentially expressed genes (DEGs) in calcified aortic valve tissues, and to analyze the correlation between DEGs and clinical features in CAVD patients. The DEGs were screened by microarray in normal and CAVD groups (n = 2 for each group), and confirmed by quantitative real-time polymerase chain reaction in normal (n = 12) and calcified aortic valve tissues (n = 34). A total of 1048 DEGs were identified in calcified aortic valve tissues, including 227 upregulated mRNAs and 821 downregulated mRNAs. Based on multiple bioinformatic analyses, three 60S ribosomal subunit components (RPL15, RPL18, and RPL18A), and two 40S ribosomal subunit components (RPS15 and RPS21) were identified as the top 5 hub genes in the protein-protein interaction network of DEGs. The expression of RPL15 and RPL18 was also found significantly decreased in calcified aortic valve tissues (both p < .01), and negatively correlated with the osteogenic differentiation marker OPN in CAVD patients (both p < .01). Moreover, inhibition of RPL15 or RPL18 exacerbated the calcification of valve interstitial cells under osteogenic induction conditions. The present study proved that decreased expression of RPL15 and RPL18 was closely associated with aortic valve calcification, which provided valuable clues to find therapeutic targets for CAVD.

Prognostic role of tissue plasminogen activator in coronary artery disease with or without aortic valve sclerosis

AIMS

We sought to investigate the relationship between circulating tissue plasminogen activator (t-PA) level and long-term outcomes in stable coronary artery disease patients with or without aortic valve sclerosis (AVSc).

METHODS AND RESULTS

Serum levels of t-PA were determined in 347 consecutive stable angina patients with (n = 183) or without (n = 164) AVSc. Outcomes were prospectively recorded as planned clinic evaluations every 6 months up to 7 years. The primary endpoint was a composite of cardiovascular death and rehospitalization due to heart failure. The secondary endpoint included all-cause mortality, cardiovascular death, and rehospitalization due to heart failure. Serum t-PA was significantly higher in AVSc than in non-AVSc patients (2131.22 pg/mL vs. 1495.85 pg/mL, P < 0.001). For patients with AVSc, those with t-PA level above the median (>1840.68 pg/mL) were more likely to meet the primary and secondary endpoints (all P < 0.001). After adjusting for potential confounding factors, serum t-PA level remained significantly predictive for each endpoint in the Cox proportional hazard models. The prognostic value of t-PA was good, with an AUC-ROC of 0.753 (P < 0.001). The combination of t-PA with traditional risk factors improved the risk reclassification of AVSc patients, with a net reclassification index of 0.857 and an integrated discrimination improvement of 0.217 (all P < 0.001). However, for patients without AVSc, both primary and secondary endpoints were similar, irrespective of t-PA levels.

CONCLUSIONS

Elevated circulating t-PA confers an increased risk for poor long-term clinical outcomes in stable coronary artery disease patients with AVSc.

Calcific aortic valve disease: from molecular and cellular mechanisms to medical therapy

Calcific aortic valve disease (CAVD) is a highly prevalent condition that comprises a disease continuum, ranging from microscopic changes to profound fibro-calcific leaflet remodelling, culminating in aortic stenosis, heart failure, and ultimately premature death. Traditional risk factors, such as hypercholesterolaemia and (systolic) hypertension, are shared among atherosclerotic cardiovascular disease and CAVD, yet the molecular and cellular mechanisms differ markedly. Statin-induced low-density lipoprotein cholesterol lowering, a remedy highly effective for secondary prevention of atherosclerotic cardiovascular disease, consistently failed to impact CAVD progression or to improve patient outcomes. However, recently completed phase II trials provide hope that pharmaceutical tactics directed at other targets implicated in CAVD pathogenesis offer an avenue to alter the course of the disease non-invasively. Herein, we delineate key players of CAVD pathobiology, outline mechanisms that entail compromised endothelial barrier function, and promote lipid homing, immune-cell infiltration, and deranged phospho-calcium metabolism that collectively perpetuate a pro-inflammatory/pro-osteogenic milieu in which valvular interstitial cells increasingly adopt myofibro-/osteoblast-like properties, thereby fostering fibro-calcific leaflet remodelling and eventually resulting in left ventricular outflow obstruction. We provide a glimpse into the most promising targets on the horizon, including lipoprotein(a), mineral-binding matrix Gla protein, soluble guanylate cyclase, dipeptidyl peptidase-4 as well as candidates involved in regulating phospho-calcium metabolism and valvular angiotensin II synthesis and ultimately discuss their potential for a future therapy of this insidious disease.

Trace elements in patients with aortic valve sclerosis

Background:

Aortic valve sclerosis (AVSc) is defined as the thickening and calcification of aortic valve cusps, in the absence of obstruction of ventricular outflow. AVSc is linked with a clear imbalance in some trace elements.

Aims:

The objective of this study was to investigate the relationship between AVSc and serum levels of iron (Fe), zinc (Zn), selenium (Se), and copper (Cu). Additionally, this research aimed to explore the clinical significance of human serum zinc, selenium, copper, and iron concentrations as a potential new biomarker for AVSc patients and to clarify the pathophysiological role in individuals at risk of developing AVSc.

Patients and methods:

The study included 40 subjects with AVSc (25% male and 75% female) who were compared with a healthy control group with the same gender ratio. AVSc was based on comprehensive echocardiographic assessments. Blood samples were taken and Zn and Cu concentrations were determined through the use of atomic absorption spectroscopy. Se was measured using an inductively coupled plasma mass spectrometry device and Fe was measured using a Beckman Coulter instrument.

Results:

There was a significant difference in the prevalence of diabetes, blood pressure levels, and body mass index between the patients and the healthy subjects (p < 0.05). The differences between the serum Fe, Se, and Cu levels of the AVSc patients and the healthy subjects (p > 0.05) were recorded. The serum Zn of AVSc patients when compared was significantly lower compared with that of the control group (p < 0.01).

Conclusion:

Patients with AVSc had an imbalance in some of the trace elements in their blood. The patient group’s valves had higher serum Cu levels and lower serum Se, Zn, and Fe concentrations compared with the healthy group’s valves. In the valve patients as compared, AVSc had a high prevalence of obesity, hypertension, and diabetes.

Activated platelets promote an osteogenic programme and the progression of calcific aortic valve stenosis

AIMS

Calcific aortic valve stenosis (CAVS) is characterized by a fibrocalcific process. Studies have shown an association between CAVS and the activation of platelets. It is believed that shear stress associated with CAVS promotes the activation of platelets. However, whether platelets actively participate to the mineralization of the aortic valve (AV) and the progression of CAVS is presently unknown. To identify the role of platelets into the pathobiology of CAVS.

METHODS AND RESULTS

Explanted control non-mineralized and mineralized AVs were examined by scanning electron microscope (SEM) for the presence of activated platelets. In-depth functional assays were carried out with isolated human valve interstitial cells (VICs) and platelets as well as in LDLR-/- apoB100/100 IGFII (IGFII) mice. Scanning electron microscope and immunogold markings for glycoprotein IIb/IIIa (GPIIb/IIIa) revealed the presence of platelet aggregates with fibrin in endothelium-denuded areas of CAVS. In isolated VICs, collagen-activated platelets induced an osteogenic programme. Platelet-derived adenosine diphosphate induced the release of autotaxin (ATX) by VICs. The binding of ATX to GPIIb/IIIa of platelets generated lysophosphatidic acid (LysoPA) with pro-osteogenic properties. In IGFII mice with CAVS, platelet aggregates were found at the surface of AVs. Administration of activated platelets to IGFII mice accelerated the development of CAVS by 2.1-fold, whereas a treatment with Ki16425, an antagonist of LysoPA receptors, prevented platelet-induced mineralization of the AV and the progression of CAVS.

CONCLUSIONS

These findings suggest a novel role for platelets in the progression of CAVS.

Stenosis coexists with compromised α1-adrenergic contractions in the ascending aorta of a mouse model of Williams-Beuren syndrome

Williams-Beuren syndrome (WBS) is a rare disorder caused by a heterozygous deletion of 26–28 contiguous genes that affects the brain and cardiovascular system. Here, we investigated whether WBS affects aortic structure and function in the complete deletion (CD) mouse model harbouring the most common deletion found in WBS patients. Thoracic aortas from 3–4 months-old male CD mice and wild-type littermates were mounted in wire myographs or were processed for histomorphometrical analysis. Nitric oxide synthase (NOS) isoforms and oxidative stress levels were assessed. Ascending aortas from young adult CD mice showed moderate (50%) luminal stenosis, whereas endothelial function and oxidative stress were comparable to wild-type. CD mice showed greater contractions to KCl. However, α1-adrenergic contractions to phenylephrine, but not with a thromboxane analogue, were compromised. Decreased phenylephrine responses were not affected by selective inducible NOS blockade with 1400 W, but were prevented by the non-selective NOS inhibitor L-NAME and the selective neuronal NOS inhibitor SMTC. Consistently, CD mice showed increased neuronal NOS expression in aortas. Overall, aortic stenosis in CD mice coexists with excessive nNOS-derived NO signaling that compromises ascending aorta α1-adrenergic contractions. We suggest that increased neuronal NOS signaling may act as a physiological ‘brake’ against the detrimental effects of stenosis.

Impact of Oxidative Stress and Protein S-Glutathionylation in Aortic Valve Sclerosis Patients with Overt Atherosclerosis

Aortic valve sclerosis (AVSc) is characterized by non-uniform thickening of the leaflets without hemodynamic changes. Endothelial dysfunction, also caused by dysregulation of glutathione homeostasis expressed as ratio between its reduced (GSH) and its oxidised form (GSSG), could represent one of the pathogenic triggers of AVSc. We prospectively enrolled 58 patients with overt atherosclerosis and requiring coronary artery bypass grafting (CABG). The incidence of AVSc in the studied population was 50%. The two groups (No-AVSc and AVSc) had similar clinical characteristics. Pre-operatively, AVSc group showed significantly lower GSH/GSSG ratio than No-AVSc group (p = 0.02). Asymmetric dimethylarginine (ADMA) concentration was significantly higher in AVSc patients compared to No-AVSc patients (p < 0.0001). Explanted sclerotic aortic valves presented a significantly increased protein glutathionylation (Pr-SSG) than No-AVSc ones (p = 0.01). In vitro, inhibition of glutathione reductase caused β-actin glutathionylation, activation of histone 2AX, upregulation of α2 smooth muscle actin (ACTA2), downregulation of platelet and endothelial cell adhesion molecule 1 (PECAM1) and cadherin 5 (CDH5). In this study, we showed for the first time that the dysregulation of glutathione homeostasis is associated with AVSc. We found that Pr-SSG is increased in AVSc leaflets and it could lead to EndMT via DNA damage. Further studies are warranted to elucidate the causal role of Pr-SSG in aortic valve degeneration.

Vitamin D supplementation lowers thrombospondin-1 levels and blood pressure in healthy adults

INTRODUCTION

Vitamin D insufficiency, defined as 25-hydroxyvitamin D (25(OH)D) levels < 75nmol/L is associated with cardio-metabolic dysfunction. Vitamin D insufficiency is associated with inflammation and fibrosis, but it remains uncertain whether these anomalies are readily reversible. Therefore, we aimed to determine the effects of vitamin D supplementation on markers of: 1) nitric oxide (NO) signaling, 2) inflammation, and 3) fibrosis, in healthy volunteers with mild hypovitaminosis.

METHODS

Healthy volunteers (n = 35) (mean age: 45 ± 11 years) with 25(OH)D levels <75nmol/L, received vitamin D supplementation (Ostelin ® capsules 2000IU) for 12 weeks. Resting systolic and diastolic blood pressures (BP) were assessed. Routine biochemistry was examined. Plasma concentrations of asymmetric dimethylarginine (ADMA), thrombospondin-1 (TSP-1), plasminogen activator inhibitor-1 (PAI-1), hs-CRP, activin-A, and follistatin-like 3 (FSTL3) were quantitated.

RESULTS

Vitamin D administration for 12 weeks significantly increased 25-(OH)D levels (48.8 ± 16 nmol/L to 100.8 ± 23.7 nmol/L, p<0.001). There was significant lowering of systolic and diastolic BP, while there was no significant change in lipid profiles, or fasting insulin. Plasma concentrations of ADMA, hs-CRP, PAI-1, activin A, and FSTL-3 did not change with vitamin D supplementation. However, there was a marked reduction of TSP-1 (522.7 ± 379.8 ng/mL vs 206.7 ± 204.5 ng/mL, p<0.001).

CONCLUSIONS

Vitamin D supplementation in vitamin D insufficient, but otherwise healthy individuals markedly decreased TSP-1 levels and blood pressure. Since TSP-1 suppresses signaling of NO, it is possible that the fall in BP is engendered by restoration of NO effect.

Effect of End-Stage Renal Disease on Rate of Progression of Aortic Stenosis

This study aimed to investigate the progression of mild-to-moderate aortic stenosis (AS) in patients with end-stage renal disease (ESRD) and determine its metabolic and hemodynamic contributors and clinical outcomes. A total of 74 patients with ESRD (50 men, age 72 ± 11 years) with mild-to-moderate AS were compared with 79 age- and gender-matched controls with normal kidney function. Clinical, laboratory, and echocardiographic features and clinical outcomes including aortic valve (AV) intervention, hospitalization due to heart failure, and cardiovascular death were analyzed. Patients with ESRD were divided into 2 subgroups according to their rate of AV area changes (group 1 [n = 28], rapid progression; and group 2 [n = 46], slow progression). Progression in the degree of AS was noted in 38% of patients with ESRD and 18% of controls (p <0.01) during comparable echocardiographic follow-up durations (29 ± 15 vs 27 ± 24 months, respectively, p = 0.57). In ESRD, patients in group 1 were older (p <0.01) with higher baseline log parathyroid hormone (p <0.01) and larger stroke volume (p = 0.03) than those in group 2. During clinical follow-up (48 ± 23 months), patients in group 1 showed poorer clinical outcomes than those in group 2 and controls (log-rank p <0.01). Age, left atrial volume index ≥42 ml/m(2), and annual increases of peak pressure gradient across the AV (mm Hg/year) demonstrated additive predictive values for prognosis. AS in ESRD progresses in an accelerated manner along with higher metabolic and hemodynamic loads on AV compared with those with normal kidney function. Accelerated progression of mild-to-moderate AS in ESRD results in poor prognosis.

Does aortic valve sclerosis predicts the severity and complexity of coronary artery disease?

AIM

We assessed the association of aortic valve sclerosis (AVS) with atherosclerotic risk factors and severity and complexity of coronary artery disease (CAD).

METHODS

In this retrospective study, a total of 482 eligible patients were divided into 2 groups: AVS present and AVS absent. All major cardiovascular risk factors and coronary lesion characteristics were included.

RESULTS

Age was the only independent predictor of AVS. AVS was not independently associated with the number of obstructive vessels, degree of lesion obstruction and SYNTAX score.

CONCLUSION

AVS is probably a benign marker of age-related degenerative changes in the heart independent of the severity and complexity of CAD.

Arterial wave reflection and aortic valve calcification in an elderly community-based cohort

BACKGROUND

Aortic valve calcification (AVC) without stenosis is common in the elderly, is associated with cardiovascular morbidity and mortality, and may progress to aortic valve stenosis. Arterial stiffness and pulse-wave reflection are important components of proximal aortic hemodynamics, but their relationship with AVC is not established.

METHODS

To investigate the relationship of arterial wave reflection and stiffness with AVC, pulse wave analysis and AVC evaluation by echocardiography were performed in 867 participants from the Cardiovascular Abnormalities and Brain Lesions study. Participants were divided into four categories on the basis of the severity and extent of AVC: (1) none or mild focal AVC, (2) mild diffuse AVC, (3) moderate to severe focal AVC, and (4) moderate to severe diffuse AVC. Central blood pressures and pulse pressure, total arterial compliance, augmentation index, and time to wave reflection were assessed using applanation tonometry.

RESULTS

Indicators of arterial stiffness and wave reflection were significantly associated with AVC severity, except for central systolic and diastolic pressures and time to reflection. After adjustment for pertinent covariates (age, sex, race/ethnicity, and estimated glomerular filtration rate), only augmentation pressure (P = .02) and augmentation index (P = .002) were associated with the severity of AVC. Multivariate logistic regression analysis revealed that augmentation pressure (odds ratio per mm Hg, 1.14; 95% confidence interval, 1.02-1.27; P = .02) and augmentation index (odds ratio per percentage point, 1.07; 95% confidence interval, 1.01-1.13; P = .02) were associated with an increased risk for moderate to severe diffuse AVC, even when central blood pressure value was included in the same model.

CONCLUSIONS

Arterial wave reflection is associated with AVC severity, independent of blood pressure values. Increased contribution of wave reflection to central blood pressure could be involved in the process leading to AVC.

The prevalence of aortic stenosis in the elderly in Iceland and predictions for the coming decades: the AGES-Reykjavík study

AIMS

To evaluate the prevalence of significant aortic valve stenosis (AS) in a randomly selected study population of elderly individuals representing the general population of Iceland. Furthermore, to predict the number of individuals likely to have severe AS in the future.

METHODS AND RESULTS

Echocardiography and computed tomography (CT) data from individuals who participated in the AGES-Reykjavik study were used. Echocardiography data from 685 individuals (58% females) aged 67-95 years were available. In both sexes combined, the prevalence for severe AS, defined as an aortic valve area index of <0.6 cm2/m2, in the age groups<70, 70-79 and ≥80 years was 0.92%, 2.4% and 7.3%, respectively. A ROC analysis on the relation between the echocardiography data and the aortic valve calcium score on CT defined a score≥500 to be indicative of severe AS. Subsequently, in a CT study cohort of 5256 individuals the prevalence of severe AS in the same age groups was 0.80%, 4.0% and 9.5%, respectively. Overall, the prevalence of severe AS by echocardiography and CT in individuals≥70 years was 4.3% and 5.9%, respectively. A prediction on the number of elderly≥70 years for the coming decades demonstrated that patients with severe AS will have increased 2.4 fold by the year 2040 and will more than triple by the year 2060.

CONCLUSION

This study, in a cohort of elderly individuals representative of the general population in a Nordic country, predicts that AS will be a large health problem in the coming decades.

Aging of the nitric oxide system: are we as old as our NO?

Background

Impaired generation and signaling of nitric oxide (NO) contribute substantially to cardiovascular (CV) risk (CVR) associated with hypertension, hyperlipidemia, and diabetes mellitus. In our rapidly aging society, advanced age is, in itself, a consistent and independent CVR factor. Many processes involved in aging are modulated by NO. We therefore postulated that aging might be independently associated with impaired NO signaling.

Methods and Results

In a prospective cohort study of 204 subjects (mean age 63±6 at study entry), we evaluated the effects of 4 years of aging on parameters of NO generation and effect, including platelet aggregability and responsiveness to NO, and plasma concentrations of the NO synthase inhibitor, asymmetric dimethylarginine (ADMA). Clinical history, lipid profile, high‐sensitivity C‐reactive protein, routine biochemistry, and 25‐hydroxyvitamin D levels were obtained at study entry and after 4 years of follow‐up. Aging was associated with marked deterioration of responsiveness of platelets to NO (P<0.0001) and increases in plasma ADMA concentrations (P<0.0001). There was a significant correlation between changes in these parameters over time (r=0.2; P=0.013). On multivariable analyses, the independent correlates of deterioration of responsiveness of platelets to NO were female gender (β=0.17; P=0.034) and low vitamin D concentrations (β=0.16; P=0.04), whereas increases in ADMA were associated with presence of diabetes (β=0.16; P=0.03) and impaired renal function (β=0.2; P=0.004).

Conclusions

Aging is associated with marked impairment of determinants of NO generation and effect, to an extent which is commensurate with adverse impact on CV outcomes. This deterioration represents a potential target for therapeutic interventions.

The prevalence, incidence, progression, and risks of aortic valve sclerosis: a systematic review and meta-analysis

OBJECTIVES

The aim of this study was to comprehensively review the epidemiology of aortic sclerosis (ASc) and its association with cardiovascular events.

BACKGROUND

ASc, which is defined as thickening or calcification of the aortic valve without significant obstruction of blood flow, is a common finding on cardiac imaging.

METHODS

We searched MEDLINE and EMBASE from inception to April 2013 for studies describing the epidemiology of ASc and performed a meta-analysis of the risk of adverse events using a random effects model.

RESULTS

Twenty-two studies were identified from the systematic review. The prevalence of ASc increased in proportion to the average age of study participants, ranging from 9% in a study in which the mean age was 54 years to 42% in a study in which the mean age was 81 years. In total, 1.8% to 1.9% of participants with ASc had progression to clinical aortic stenosis per year. There was a 68% increased risk of coronary events in subjects with ASc (hazard ratio [HR]: 1.68; 95% confidence interval [CI]: 1.31 to 2.15), a 27% increased risk of stroke (HR: 1.27; 95% CI: 1.01 to 1.60), a 69% increased risk of cardiovascular mortality (HR: 1.69; 95% CI: 1.32 to 2.15), and a 36% increased risk of all-cause mortality (HR: 1.36; 95% CI: 1.17 to 1.59).

CONCLUSIONS

ASc is a common finding that is more prevalent with older age. Despite low rates of progression to ASc, there is an independent increase in morbidity and mortality associated with the condition.

Impact of hypertension and renin-angiotensin system inhibitors in aortic stenosis

BACKGROUND

Experimental studies revealed that renin-angiotensin system (RAS) could play a crucial role in the pathophysiology of aortic stenosis (AS). The objectives of this study were to examine (i) the impact of hypertension on AS progression and clinical events and (ii) the effect of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-receptor blockers (ARBs).

MATERIALS AND METHODS

In this observational study, we retrospectively analysed clinical and Doppler echocardiographic data prospectively collected in 338 patients with AS. Patients were separated into four groups: patients without hypertension and not treated by RAS medication (Ctrl group), patients with hypertension but not treated by RAS medication (HTN group), patients treated with ACEIs, and patients treated with ARBs. AS progression rate was assessed by the annualized increase in peak aortic jet velocity.

RESULTS

Compared with Ctrl group, patients in HTN group had faster stenosis progression (P = 0·01). Patients on ARBs had slower AS progression compared with Ctrl (trend P = 0·10) and HTN (P = 0·002) groups, whereas patients on ACEIs had similar progression rate compared with Ctrl group (P = NS) but lower compared with HTN group (P = 0·02). On multivariable analysis, compared with Ctrl group, HTN group was associated with faster AS progression rate (P = 0·002), whereas ARBs with slower progression (P = 0·0008). During a mean follow-up of 6·2 ± 2·4 years, HTN (hazard ratio [HR] = 2·45; P = 0·006) and ACEI (HR = 2·30; P = 0·01) groups were associated with a significant increase in all-cause mortality compared with Ctrl group, whereas ARB group (HR: 0·89; P = 0·80) not. In multivariable analysis, HTN and ACEI groups remained associated with increased mortality.

CONCLUSIONS

Hypertension is associated with significantly faster stenosis progression and higher incidence of clinical events in patients with AS. ARBs but not ACEs were found to abolish the increased risk of mortality associated with hypertension.

Oxidative stress and nitric oxide pathway in adult patients who are candidates for cardiac surgery: patterns and differences

OBJECTIVES

We investigated whether oxidative stress and the arginine/nitric oxide pathway differ in control subjects and in adult patients who are candidates for the three most common cardiac surgical operations: coronary bypass surgery, aortic valve replacement for calcific non-rheumatic aortic stenosis or mitral valve repair for degenerative mitral insufficiency.

METHODS

In this prospective observational study, we studied 165 consecutive patients undergoing surgery from January to June 2011 (coronary bypass surgery, n = 63; aortic valve replacement for calcific non-rheumatic aortic stenosis, n = 51; mitral valve repair for degenerative mitral insufficiency, n = 51). Thirty-three healthy subjects with cardiovascular risk factors similar to surgery patients were also studied (Controls). Oxidative stress (the ratio of reduced and oxidized glutathione and urinary isoprostane), antioxidants (alpha- and gamma tocopherol) and factors involved in nitric oxide synthesis (arginine, symmetric and asymmetric dimethylarginine) were measured before surgery. Analysis of variance general linear models and principal component analysis were used for statistical analysis.

RESULTS

Surgical patients had increased levels of oxidative stress and decreased levels of antioxidants. Increased levels of nitric oxide inhibitor asymmetric dimethylarginine were detected in surgical candidates, suggesting arginine/nitric oxide pathway impairment. Concerning the differences among surgical procedures, higher oxidative stress and a major imbalance of the ratio between substrate and inhibitors of nitric oxide synthesis were evidenced in patients who were candidates for mitral valve repair with respect to coronary bypass surgery patients and patients with calcific non-rheumatic aortic stenosis.

CONCLUSIONS

Patients undergoing cardiac surgery have increased oxidative stress and a trend towards an impaired arginine/nitric oxide pathway with respect to Controls. Patients affected by mitral valve regurgitation show more pronounced perturbations in these pathways. The clinical implications of these findings need to be investigated.

Reciprocal regulation of NO signaling and TXNIP expression in humans: impact of aging and ramipril therapy

BACKGROUND

Impaired tissue responsiveness to nitric oxide (NO) occurs in many cardiovascular diseases as well as with advanced age and is a correlate of poor outcomes. This phenomenon results from oxidative stress, with NO "scavenging" and dysfunction of soluble guanylate cyclase (sGC). Thioredoxin-interacting protein (TXNIP) is a major intracellular regulator of inflammatory activation and redox stress, but its interactions with NO/sGC are poorly understood. We have now evaluated the relationship between platelet TXNIP expression and function of the NO/sGC axis in subjects of varying age and during therapy with ramipril.

METHODS & RESULTS

Young (n=42) and aging (n=49) subjects underwent evaluation of platelet TXNIP content. Aging subjects additionally had measurements of platelet NO responsiveness and routine biochemistry. Platelet TXNIP content was greater (376±33 units) in the aging compared to younger subjects (289±13 units; p<0.05). In the aging subjects there was a significant negative correlation (r=-0.50, p<0.001) between platelet TXNIP content and NO responsiveness. In a separate cohort of 15 subjects two week treatment with ramipril, which reversed platelet NO resistance and potentiated sGC activity, also decreased platelet TXNIP content by 40% (p=0.011).

CONCLUSIONS

Platelet TXNIP content increases with aging, varies inversely with responsiveness to NO, and diminishes rapidly following treatment with ramipril. These data suggest that TXNIP-induced oxidative stress may be a critical modulator of tissue resistance to NO, a fundamental basis for cardiovascular disease. Analogously suppression of TXNIP expression can potentially be utilized as an index of restoration of cardiovascular homeostasis.

Imaging of valvular heart disease

Imaging plays a fundamental role in the current diagnosis and treatment of valvular heart disease (VHD) and in the preclinical and clinical research aiming at the development of novel pharmacologic or interventional therapies. Doppler echocardiography remains the primary imaging technique for the clinical management of VHD. However, the multifaceted and complex nature of VHD and the rapid development of transcatheter valve therapies has led to a spectacular increase in the use of multimodality imaging in the past decade. The purpose of this article is to review the current and emerging roles of the different imaging modalities in the diagnosis and treatment of VHD and to present the new directions for future research and clinical applications.

Progression of aortic valve stenosis is associated with bone remodelling and secondary hyperparathyroidism in elderly patients--the COFRASA study

AIMS

There is currently no medical therapy that can prevent the progression of aortic valve stenosis (AS). Recent data highlight a possible relationship between bone metabolism and AS progression but prospective data are lacking.

METHODS AND RESULTS

Serum levels of calcium, phosphorus, creatinine, 25-OH vitamin D, intact parathyroid hormon (iPTH), C-terminal-telopeptide of type-1-collagen (CTX) and osteocalcin were assessed at baseline in 110 elderly patients (age ≥70 years) with at least mild AS. CTX/osteocalcin ratio was calculated as a marker of bone remodelling balance. AS severity was assessed at baseline and 1-year based on the mean gradient. Two-thirds of patients had low 25-OH vitamin D and 20% had secondary hyperparathyroidism. AS progression was not associated with age, glomerular filtration rate (GFR), calcium and phosphorus levels, calcium-phosphorus product, but significantly with iPTH, CTX/osteocalcin and vitamin D status (all P < 0.01). There was no correlation between iPTH and CTX/osteocalcin (R = 0.04, P = 0.70) and AS progression was associated with CTX/osteocalcin (R = 0.42, P = 0.009), but not with iPTH (R = 0.10, P = 0.55) in patients with normal vitamin D levels, whereas it was associated with iPTH (R = 0.47, P < 0.001) and not with CTX/osteocalcin (R = 0.04, P = 0.73) in those with low vitamin D levels, especially if mild renal insufficiency was present (R = 0.61, P < 0.001).

CONCLUSION

In elderly patients with AS, we observed an association between AS progression and vitamin D, iPTH and CTX/osteocalcin ratio and their respective influence varied according to the vitamin D status. In patients with normal vitamin D levels, AS progression was associated with a bone resorptive balance, whereas in patients with low vitamin D levels, AS progression was associated with iPTH and secondary hyperparathyroidism, especially if mild renal insufficiency was present. These findings may have important prognostic and therapeutic implications. Trial registration information: Clinicaltrials.gov identifier number: NCT00338676, funded by AP-HP, the COFRASA study.