Impact of chronic kidney disease on the presence and severity of aortic stenosis in patients at high risk for coronary artery disease

Impact of Uremic Toxins on Endothelial Dysfunction in Chronic Kidney Disease: A Systematic Review

Patients with chronic kidney disease (CKD) are at a highly increased risk of cardiovascular complications, with increased vascular inflammation, accelerated atherogenesis and enhanced thrombotic risk. Considering the central role of the endothelium in protecting from atherogenesis and thrombosis, as well as its cardioprotective role in regulating vasorelaxation, this study aimed to systematically integrate literature on CKD-associated endothelial dysfunction, including the underlying molecular mechanisms, into a comprehensive overview. Therefore, we conducted a systematic review of literature describing uremic serum or uremic toxin-induced vascular dysfunction with a special focus on the endothelium. This revealed 39 studies analyzing the effects of uremic serum or the uremic toxins indoxyl sulfate, cyanate, modified LDL, the advanced glycation end products N-carboxymethyl-lysine and N-carboxyethyl-lysine, p-cresol and p-cresyl sulfate, phosphate, uric acid and asymmetric dimethylarginine. Most studies described an increase in inflammation, oxidative stress, leukocyte migration and adhesion, cell death and a thrombotic phenotype upon uremic conditions or uremic toxin treatment of endothelial cells. Cellular signaling pathways that were frequently activated included the ROS, MAPK/NF-κB, the Aryl-Hydrocarbon-Receptor and RAGE pathways. Overall, this review provides detailed insights into pathophysiological and molecular mechanisms underlying endothelial dysfunction in CKD. Targeting these pathways may provide new therapeutic strategies reducing increased the cardiovascular risk in CKD.

Associations between aortic regurgitation severity and risk of incident myocardial infarction and stroke among patients with degenerative aortic valve disease: insights from a large Chinese population-based cohort study

OBJECTIVES

Few studies have explored whether the risk of myocardial infarction (MI) or stroke varies among patients with degenerative aortic valve disease (DAVD) with different severity of aortic regurgitation (AR) or not. Thus, a prospective study was conducted to elucidate the causal relationship between AR severity and risk of incident MI and stroke among patients with DAVD recruited from a general population in Northeast China.

DESIGN

Prospective cohort study.

SETTING

Community-based study carried out in rural areas of Northeast China.

METHODS

There were 3675 patients with DAVD aged ≥45 years eligible for the prospective study. During a median follow-up time of 4.64 years, 99 participants lost to follow-up. Cox regression analyses were used to investigate the association between baseline AR severity and the risk of incident MI or stroke.

RESULTS

In the final cohort of 3576 patients with DAVD, there were 3153 patients without AR (88.2%), 386 patients with mild AR (10.8%) and 37 patients with moderate or severe AR (1.0%). Multivariate analyses showed that, compared with participants without AR, those with moderate/severe AR were associated with 8.33 and 6.22-fold increased risk of MI and MI mortality, respectively. However, no significant associations between AR and the risk of stroke or stroke mortality were observed.

CONCLUSIONS

As compared with no AR, moderate/severe AR but not mild AR was an independent predictor for the risk of MI and MI mortality. AR was not significantly associated with stroke or stroke mortality, irrespective of AR severity. Secondary prevention strategies should be taken to delay the progression of DAVD and thus reduce the incidence of MI.

Uremic Toxins Affecting Cardiovascular Calcification: A Systematic Review

Cardiovascular calcification is highly prevalent and associated with increased morbidity in chronic kidney disease (CKD). This review examines the impact of uremic toxins, which accumulate in CKD due to a failing kidney function, on cardiovascular calcification. A systematic literature search identified 41 uremic toxins that have been studied in relation to cardiovascular calcification. For 29 substances, a potentially causal role in cardiovascular calcification was addressed in in vitro or animal studies. A calcification-inducing effect was revealed for 16 substances, whereas for three uremic toxins, namely the guanidino compounds asymmetric and symmetric dimethylarginine, as well as guanidinosuccinic acid, a calcification inhibitory effect was identified in vitro. At a mechanistic level, effects of uremic toxins on calcification could be linked to the induction of inflammation or oxidative stress, smooth muscle cell osteogenic transdifferentiation and/or apoptosis, or alkaline phosphatase activity. For all middle molecular weight and protein-bound uremic toxins that were found to affect cardiovascular calcification, an increasing effect on calcification was revealed, supporting the need to focus on an increased removal efficiency of these uremic toxin classes in dialysis. In conclusion, of all uremic toxins studied with respect to calcification regulatory effects to date, more uremic toxins promote rather than reduce cardiovascular calcification processes. Additionally, it highlights that only a relatively small part of uremic toxins has been screened for effects on calcification, supporting further investigation of uremic toxins, as well as of associated post-translational modifications, on cardiovascular calcification processes.

Urea level is an independent predictor of mortality in patients with severe aortic valve stenosis

Introduction

Severe aortic stenosis (AS) is the most common valvular heart disease in the western world. Various factors are related to severe AS prognosis, including chronic kidney disease. The aim of this study was to evaluate the prognostic value of urea level in patients with severe AS.

Methods

We prospectively enrolled 142 patients (79.1±9.4 years, 88 women) with severe AS (mean valve area 0.67± 0.17 cm²). Clinical assessment, blood tests and echocardiography were performed at enrollment and follow up. The patient population was divided into low and high urea level groups, according to the median urea level at enrollment (72 patients, mean urea 35.5±6.2 mg/dL and 70 patients, mean urea 61.1±17.8 mg/dL, respectively). Hundred and twelve patients (79%) underwent aortic valve intervention. The primary endpoint was all-cause and cardiovascular mortality.

Outcomes

During follow-up of 37±19.5 months, 56 (37.1%) patients died, 39 due to cardiovascular causes. In univariate analysis, age, urea level, creatinine, New York Heart Association (NYHA) class and aortic valve intervention were associated with all-cause mortality. However, in multivariate analysis only aortic valve intervention and blood urea were independent predictors of all-cause mortality (HR 0.494; 95% CI 0.226–0.918, P = 0.026 and HR 1.015; 95% CI 1.003–1.029, P = 0.046 respectively). Urea level, NYHA class and age were also significant predictors of cardiovascular mortality. Whereas, in multivariate analysis, only urea level predicted cardiovascular mortality in these patients (HR 1.017; CI 1.003–1.031 P = 0.019).

Conclusions

Blood urea, a generally readily available and routinely determined marker of renal function, is an independent prognostic factor in patients with severe AS.

[The renin-angiotensin-aldosterone system as a potential target for therapy in patients with calcific aortic stenosis: a literature review]

Calcific aortic valve stenosis (CAVS) is a serious socio-economic problem in developed countries because this disease is the most common indication for aortic valve replacement. Currently, there are no methods for non-invasive treatment of CAVS. Nevertheless, it is assumed that effective drug therapy for CAVS can be developed on the basis of modulators of the renin-angiotensin-aldosterone system (RAAS), which is involved in the pathogenesis of this disease. The purpose of this paper is to compile and analyze current information on the role of RAAS in the CAVS pathophysiology. Recent data on the effectiveness of RAAS inhibition are reviewed.

Prevalence and Outcomes of Left-Sided Valvular Heart Disease Associated With Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is an adverse prognostic marker for valve intervention patients; however, the prevalence and related outcomes of valvular heart disease in CKD patients is unknown.

METHODS AND RESULTS

Included patients underwent echocardiography (1999-2013), had serum creatinine values within 6 months before index echocardiogram, and had no history of valve surgery. CKD was defined as diagnosis based on the International Classification of Diseases, Ninth Revision or an estimated glomerular filtration rate <60 mL/min per 1.73 m2. Qualitative assessment determined left heart stenotic and regurgitant valve lesions. Cox models assessed CKD and aortic stenosis (AS) interaction for subsequent mortality; analyses were repeated for mitral regurgitation (MR). Among 78 059 patients, 23 727 (30%) had CKD; of these, 1326 were on hemodialysis. CKD patients were older; female; had a higher prevalence of hypertension, hyperlipidemia, diabetes, history of coronary artery bypass grafting/percutaneous coronary intervention, atrial fibrillation, and heart failure ≥mild AS; and ≥mild MR (all P<0.001). Five-year survival estimates of mild, moderate, and severe AS for CKD patients were 40%, 34%, and 42%, respectively, and 69%, 54%, and 67% for non-CKD patients. Five-year survival estimates of mild, moderate, and severe MR for CKD patients were 51%, 38%, and 37%, respectively, and 75%, 66%, and 65% for non-CKD patients. Significant interaction occurred among CKD, AS/MR severity, and mortality in adjusted analyses; the CKD hazard ratio increased from 1.8 (non-AS patients) to 2.0 (severe AS) and from 1.7 (non-MR patients) to 2.6 (severe MR).

CONCLUSIONS

Prevalence of at least mild AS and MR is substantially higher and is associated with significantly lower survival among patients with versus without CKD. There is significant interaction among CKD, AS/MR severity, and mortality, with increasingly worse outcomes for CKD patients with increasing AS/MR severity.

Association of CKD with Outcomes Among Patients Undergoing Transcatheter Aortic Valve Implantation

BACKGROUND AND OBJECTIVES

Despitethe multiple depicted associations of CKD with reduced cardiovascular and overall prognoses, the association of CKD with outcome of patients undergoing transcatheter aortic valve implantation has still not been well described.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data from all hospitalized patients who underwent transcatheter aortic valve implantation procedures between January 1, 2010 and December 31, 2013 in Germany were evaluated regarding influence of CKD, even in the earlier stages, on morbidity, in-hospital outcomes, and costs.

RESULTS

A total of 28,716 patients were treated with transcatheter aortic valve implantation. A total of 11,189 (39.0%) suffered from CKD. Patients with CKD were predominantly women; had higher rates of comorbidities, such as coronary artery disease, heart failure at New York Heart Association 3/4, peripheral artery disease, and diabetes; and had a 1.3-fold higher estimated logistic European System for Cardiac Operative Risk Evaluation value. In-hospital mortality was independently associated with CKD stage ≥3 (up to odds ratio, 1.71; 95% confidence interval, 1.35 to 2.17; P<0.05), bleeding was independently associated with CKD stage ≥4 (up to odds ratio, 1.82; 95% confidence interval, 1.47 to 2.24; P<0.001), and AKI was independently associated with CKD stages 3 (odds ratio, 1.83; 95% confidence interval, 1.62 to 2.06) and 4 (odds ratio, 2.33; 95% confidence interval, 1.92 to 2.83 both P<0.001). The stroke risk, in contrast, was lower for patients with CKD stages 4 (odds ratio, 0.23; 95% confidence interval, 0.16 to 0.33) and 5 (odds ratio, 0.24; 95% confidence interval, 0.15 to 0.39; both P<0.001). Lengths of hospital stay were, on average, 1.2-fold longer, whereas reimbursements were, on average, only 1.03-fold higher in patients who suffered from CKD.

CONCLUSIONS

This analysis illustrates for the first time on a nationwide basis the association of CKD with adverse outcomes in patients who underwent transcatheter aortic valve implantation. Thus, classification of CKD stages before transcatheter aortic valve implantation is important for appropriate risk stratification.

Mean Transaortic Gradient is an Emerging Predictor of Chronic Kidney Disease in Elderly Patients

Arterial hypertension (AH) is a major risk factor for chronic kidney disease (CKD). However, whether AH maintains this role in the development of CKD in elderly patients with aortic stenosis (AS) or whether transaortic gradient influences CKD remains unclear. Consecutive hospitalized patients were prospectively recruited to evaluate the relationship between AS and CKD. In all patients, transthoracic 2-dimensional echocardiography was performed to evaluate AS; renal function was evaluated using the Chronic Kidney Disease Epidemiology Collaboration formula. A total of 346 patients were included in the study (mean age: 79.5 ± 7.4 years): 104 had diabetes mellitus (DM), 298 had AH, and 59 (moderate: 52; severe: 7) showed AS. After multivariate analysis, age ( P <.01), DM ( P = .02), and mean transaortic gradient ( P = .03), but not AH, were independent predictors of CKD. Both in the presence (n = 59) or absence (n = 287) of AS, the estimated glomerular filtration rate did not differ in patients with (51 ± 24 mL/min/1.73 m2 and 59 ± 25 mL/min/1.73 m2, respectively) and those without AH (50 ± 21 mL/min/1.73 m2 and 65 ± 24 mL/min/1.73 m2, respectively). In the whole population, for each mm Hg of mean transaortic gradient, the risk of CKD increased by 2.5 times.

Impact of chronic kidney disease on the outcomes of transcatheter aortic valve implantation: results from the FRANCE 2 registry

AIMS

The aim of this study was to assess the influence of chronic kidney disease (CKD) classification on clinical outcomes in patients undergoing transcatheter aortic valve implantation (TAVI).

METHODS AND RESULTS

Data of 2,929 consecutive patients undergoing TAVI in the FRANCE 2 registry were analysed. Patients were divided into five groups: CKD 1+2, 3a, 3b, 4, and 5. Both 30-day and one-year mortality rates were significantly increased and positively correlated with CKD severity in all groups. After adjusting for significant influential confounders in a Cox regression multivariate model, CKD 4 and 5 were associated with increased risk of both 30-day mortality and one-year mortality when compared with CKD 1+2 as the reference. This higher mortality was predominantly driven by renal failure and infection in patients with CKD 4 and 5, respectively. Procedural success rate in CKD 5 was significantly lower than that in other groups. All CKD patients trended towards a higher incidence of acute kidney injury (AKI), in parallel with the degree of CKD severity.

CONCLUSIONS

Classification of CKD stages before TAVI allows risk stratification for 30-day and one-year clinical outcomes. CKD 3b, 4 and 5 correlate with poor outcome and are considered a significant risk for TAVI.

Mid-term prognostic value of coronary artery disease in patients undergoing transcatheter aortic valve implantation: a meta-analysis of adjusted observational results

AIMS

Coronary artery disease (CAD) negatively affects prognosis in patients undergoing surgical aortic valve replacement, being currently evaluated in the most common used risk score. Our meta-analysis aims to clarify the prognostic role of CAD on mid-term survival in patients undergoing TAVI.

METHODS AND RESULTS

Studies reporting multivariate predictors of adverse outcomes in patients undergoing TAVI were systematically searched for and pooled, when appropriate, using a random-effect method. 960 citations were first screened and finally 7 studies (2472 patients) were included. Diagnosis of CAD was reported in 52%(42-65) of patients and 1169 Edwards SAPIEN and 1303 CoreValve prostheses were implanted. After a median follow up of 452 days (357-585) 24% of patients (19-33) died, and 23 (14-32) for cardiovascular death. At pooled analysis of multivariate approach, diagnosis of coronary artery disease did not increase risk of death (OR 1.0, 95% CI, confidence interval, 0.67-1.50 I(2) 0%).

CONCLUSION

CAD does not affect mid-term TAVI outcome: this finding should be weighted to accurately evaluate risk and strategies for patients with severe aortic stenosis.

Echocardiographic integrated backscatter for detecting progression and regression of aortic valve calcifications in rats

Background

Calcification is an independent predictor of mortality in calcific aortic valve disease (CAVD). The aim of this study was to evaluate the use of non-invasive, non-ionizing echocardiographic calibrated integrated backscatter (cIB) for monitoring progression and subsequent regression of aortic valvular calcifications in a rat model of reversible renal failure with CAVD, compared to histology.

Methods

28 male Wistar rats were prospectively followed during 21 weeks. Group 1 (N=14) was fed with a 0.5% adenine diet for 9 weeks to induce renal failure and CAVD. Group 2 (N=14) received a standard diet. At week 9, six animals of each group were killed. The remaining animals of group 1 (N=8) and group 2 (N=8) were kept on a standard diet for an additional 12 weeks. cIB of the aortic valve was calculated at baseline, 9 and 21 weeks, followed by measurement of the calcified area (Ca Area) on histology.

Results

At week 9, cIB values and Ca Area of the aortic valve were significantly increased in the adenine-fed rats compared to baseline and controls. After 12 weeks of adenine diet cessation, cIB values and Ca Area of group 1 decreased compared to week 9, while there was no longer a significant difference compared to age-matched controls of group 2.

Conclusions

cIB is a non-invasive tool allowing quantitative monitoring of CAVD progression and regression in a rat model of reversible renal failure, as validated by comparison with histology. This technique might become useful for assessing CAVD during targeted therapy.

Global left ventricular load in asymptomatic aortic stenosis: covariates and prognostic implication (the SEAS trial)

Introduction

Valvuloarterial impedance (Zva) is a measure of global (combined valvular and arterial) load opposing left ventricular (LV) ejection in aortic stenosis (AS). The present study identified covariates and tested the prognostic significance of global LV load in patients with asymptomatic AS.

Methods

1418 patients with mild-moderate, asymptomatic AS in the Simvastatin Ezetimibe in Aortic Stenosis (SEAS) study were followed for a mean of 43±14 months during randomized, placebo-controlled treatment with combined simvastatin 40 mg and ezetimibe 10 mg daily. High global LV load was defined as Zva >5 mm Hg/ml/m². The impact of baseline global LV load on rate of major cardiovascular (CV) events, aortic valve events and total mortality was assessed in Cox regression models reporting hazard ratio (HR) and 95% Confidence Intervals (CI).

Results

High global LV load was found in 18% (n=252) of patients and associated with female gender, higher age, hypertension, more severe AS and lower ejection fraction (all p<0.05). A total of 476 major CV events, 444 aortic valve events and 132 deaths occurred during follow-up. In multivariate Cox regression analyses, high global LV load predicted higher rate of major CV events (HR 1.35 [95% CI 1.08-1.71], P=0.010) and aortic valve events (HR 1.41 [95% CI 1.12-1.79], P=0.004) independent of hypertension, LV ejection fraction, female gender, age, abnormal LV geometry and AS severity, but failed to predict mortality.

Conclusion

In asymptomatic AS, assessment of global LV load adds complementary information on prognosis to that provided by hypertension or established prognosticators like AS severity and LV ejection fraction.