Arterial stiffness in chronic kidney disease

Causes of Chronic Kidney Disease and Their Associations with Cardiovascular Risk and Disease in a Sub-Saharan Low-Income Population

Introduction

The causes of chronic kidney disease (CKD) in people living in Sub-Saharan Africa await identification. Also, whether cardiovascular risk and disease extent differ among patients with different CKD etiologies is uncertain.

Methods

In this prospective cross-sectional study, we examined the presumed causes of chronic kidney disease (CKD) and their relationships with cardiovascular risk and disease in 743 consecutive patients from a sub-Saharan low-income population.

Results

Hypertensive nephropathy (HNP) (60.2%), diabetic nephropathy (DNP) (24.4%), HIV associated CKD (20.0%) and glomerular disease (13.6%) comprised the major CKD etiologies upon enrolment at the hospital nephrology clinic. Pulse pressure was larger in patients with concurrent HNP and DNP than in those with HNP only (p<0.001). Pulse pressure and systolic blood pressure were larger in HNP or/and DNP patients than those with HIV associated CKD and glomerular disease (p=0.04 to <0.001). Cardiovascular disease was more prevalent in patients with HNP and concurrent HNP and DNP than those from other etiologic categories (p<0.05). HNP and DNP were associated with pulsatile pressures (pulse pressure and systolic blood pressure) independent of one another (p<0.01). In adjusted product of coefficient mediation analysis, mean arterial or distending pressure accounted fully for the potential impact of HNP on pulsatile pressures (103.9-115.7%) but not for that of DNP on the respective pressures (-2.0%-(-)7.5%).

Conclusion

HNP is by far the most prevalent presumed cause of CKD in this African population. Cardiovascular risk and disease differ markedly across CKD etiological categories.

Cardiovascular Consequences of Acute Kidney Injury: Treatment Options

Soon after haemodialysis was introduced into clinical practice, a high risk of cardiac death was noted in end-stage renal disease. However, only in the last decade has it become clear that any renal injury, acute or chronic, is associated with high overall and cardiovascular lethality. The need for early recognition of kidney damage in cardiovascular pathology to assess risk and develop tactics for patient management contributed to the emergence of the concept of the "cardiorenal syndrome" (CRS). CRS is a pathophysiological disorder of the heart and kidneys in which acute or chronic dysfunction of one of these organs leads to acute or chronic dysfunction of the other. The beneficial effect of ultrafiltration as a component of renal replacement therapy (RRT) is due to the elimination of hyperhydration, which ultimately affects the improvement in cardiac contractile function. This review considers the theoretical background, current status of CRS, and future potential of RRT, focusing on the benefits of ultrafiltration as a therapeutic option.

Hypertension and cardiomyopathy associated with chronic kidney disease: epidemiology, pathogenesis and treatment considerations

Chronic kidney disease (CKD) is a complex condition with a prevalence of 10-15% worldwide. An inverse-graded relationship exists between cardiovascular events and mortality with kidney function which is independent of age, sex, and other risk factors. The proportion of deaths due to heart failure and sudden cardiac death increase with progression of chronic kidney disease with relatively fewer deaths from atheromatous, vasculo-occlusive processes. This phenomenon can largely be explained by the increased prevalence of CKD-associated cardiomyopathy with worsening kidney function. The key features of CKD-associated cardiomyopathy are increased left ventricular mass and left ventricular hypertrophy, diastolic and systolic left ventricular dysfunction, and profound cardiac fibrosis on histology. While these features have predominantly been described in patients with advanced kidney disease on dialysis treatment, patients with only mild to moderate renal impairment already exhibit structural and functional changes consistent with CKD-associated cardiomyopathy. In this review we discuss the key drivers of CKD-associated cardiomyopathy and the key role of hypertension in its pathogenesis. We also evaluate existing, as well as developing therapies in the treatment of CKD-associated cardiomyopathy.

Physiological and pathophysiological functions of NLRP6: pro- and anti-inflammatory roles

The nucleotide-binding oligomerization and leucine-rich repeat receptor (NLR) protein family consists of important immune sensors that form inflammasomes, a cytosolic multi-protein platform that induces caspase-1 activation and is involved in different inflammatory pathologies. The NLR family pyrin domain containing 6 (NLRP6) is a receptor that can signal by forming inflammasomes, but which can also play an important role without forming inflammasomes. NLRP6 regulates intestinal homeostasis and inflammation, but also is involved in cancer, the nervous system or liver diseases, with both protective and deleterious consequences. In the present article, we review the different roles of NLRP6 in these processes and offer new insights into NLRP6 activation.

This review discusses emerging roles for the NLR family pyrin domain containing 6 receptor (NLRP6) in intestinal homeostasis, inflammation, cancer, the nervous system and liver disease.

Risk for subsequent hypertension and cardiovascular disease after living kidney donation: is it clinically relevant?

The first successful live donor kidney transplant was performed in 1954. Receiving a kidney transplant from a live kidney donor remains the best option for increasing both life expectancy and quality of life in patients with end-stage kidney disease. However, ever since 1954, there have been multiple questions raised on the ethics of live kidney donation in terms of negative impacts on donor life expectancy. Given the close relationship between reduced kidney function in patients with chronic kidney disease (CKD) and hypertension, cardiovascular disease and cardiovascular mortality, information on the impact of kidney donation on these is particularly relevant. In this article, we review the existing evidence, focusing on the more recent studies on the impact of kidney donation on all-cause mortality, cardiovascular mortality, cardiovascular disease and hypertension, as well as markers of cardiovascular damage including arterial stiffness and uraemic cardiomyopathy. We also discuss the similarities and differences between the pathological reduction in renal function that occurs in CKD, and the reduction in renal function that occurs because of a donor nephrectomy. Kidney donors perform an altruistic act that benefits individual patients as well as the wider society. They deserve to have high-quality evidence on which to make informed decisions.

Low serum 3-methyl histidine level is associated with aortic stiffness in maintenance hemodialysis patients

3-Methylhistidine (3MH) is an indicator of muscle catabolism. Subclinical protein malnutrition is an independent predictor of aortic stiffness (AS). We aimed to study the relationship between serum 3MH level and AS among patients undergoing maintenance hemodialysis (MHD). Carotid-femoral pulse wave velocity was applied to measure AS of 110 MHD patients. Serum 3MH levels were analyzed using high-performance liquid chromatography and mass spectrometry. AS was defined as cfPWV >10 m/s. Forty-five (40.9%) patients were categorized as having AS. Multivariable logistic (odds ratio: 0.792, p < 0.001) and linear (β = -0.322, p < 0.001) regression analysis revealed that serum 3MH is an independent factor associated with AS among MHD patients. The diagnostic power of 3MH for AS in patients undergoing MHD was 0.691 (95% CI: 0.595-0.775, p = 0.0002). Low serum 3MH levels could be a potential biomarker related to AS among MHD patients.

The relationship between hepatic fibrosis and arterial stiffness in hemodialysis patients

INTRODUCTION

The main cause of death in hemodialysis patients is cardiovascular diseases. Increased arterial stiffness is a predictor of cardiovascular events for hemodialysis patients. Among the nondialysis patient population, arterial stiffness increases in those with hepatic fibrosis and nonalcoholic fatty liver disease. This study aims to examine the relationship between hepatic fibrosis and arterial stiffness in hemodialysis patients for the first time in the literature.

MATERIAL AND METHOD

The study includes chronic hemodialysis patients over 18 years of age who had been treated for hemodialysis for at least 6 months. Patients with chronic liver disease, chronic viral hepatitis (HBV and HCV), alcohol use, or liver disease accompanied by polycystic kidney disease and active infection were excluded. Hepatic fibrosis scores were measured using the FibroScan device. Single-cuff Mobil-o-Graph was used for measurement of arterial stiffness.

RESULTS

Fifty-nine patients were enrolled; 54.2% of the patients were male, and the mean age was 53.9 ± 12.9 years. Thirty-nine percent of the patients had diabetes. Average pulse wave velocity (PWV) value of the patients was 8.3 ± 1.6 m/s, and it had positive correlation with age, CAP score, fibrosis score, and body mass index and showed negative correlation to albumin. It was seen that the patients with a PWV value ≥ 10 m/s have significantly higher CAP score compared with the patients with a PWV < 10 m/s. When the factors predicting PWV were examined in the regression analysis, age and systolic blood pressure were found to be determinants.

CONCLUSION

Increased hepatic fibrosis in hemodialysis patients is associated with increased arterial stiffness, but this relationship is not independent.

Determinants of arterial stiffness in patients with atrial fibrillation

BACKGROUND

Arterial stiffness has emerged as a strong predictor of cardiovascular disease, end-organ damage and all-cause mortality. Although increased arterial stiffness has been described as a predictor of atrial fibrillation, the relationship between arterial stiffness and atrial fibrillation is uncertain.

AIM

We assessed arterial stiffness in patients with atrial fibrillation compared with that in a control group.

METHODS

We enrolled 151 patients with atrial fibrillation who underwent pulmonary vein isolation (mean age 71.1±9.8 years) and 54 control patients with similar cardiovascular risk profiles and sinus rhythm, matched for age (mean age 68.6±15.7 years) and sex. Aortic distensibility as a measure of arterial stiffness was assessed by transoesophageal echocardiography. Patients with atrial fibrillation were followed over a median of 21 (15 to 31) months.

RESULTS

Compared with control patients, patients with atrial fibrillation had significantly lower aortic distensibility (1.8±1.1 vs. 2.1±1.1 10^-3mmHg^-1; P=0.02). Age (hazard ratio 0.67, 95% confidence interval 0.003 to 0.03; P=0.02) and pulse pressure (hazard ratio -1.35, 95% confidence interval -0.07 to -0.03; P<0.0001) were the strongest predictors of decreased aortic distensibility in the study cohort. This effect was independent of the type of atrial fibrillation (paroxysmal/persistent). During follow-up, decreased aortic distensibility was a predictor of cardiovascular and all-cause hospitalizations, as well as recurrences of atrial fibrillation, with a higher incidence rate of events in patients in the lowest aortic distensibility quartile (P=0.001).

CONCLUSIONS

Aortic distensibility was significantly reduced in patients with atrial fibrillation, with age and pulse pressure showing the strongest correlation, independent of the type of atrial fibrillation. Additionally, decreased aortic distensibility was associated with cardiovascular and all-cause hospitalizations, as well as recurrences of atrial fibrillation, which showed a quartile-dependent occurrence.

A Randomized, Double-Blind, Placebo-Controlled Clinical Trial of an Omega-3 Fatty Acid Supplement in Patients With Predialysis Chronic Kidney Disease

OBJECTIVE

Omega-3 fatty acids may reduce albuminuria and cardiovascular risk factors in patients with chronic kidney disease (CKD). We aimed to assess the effects of omega-3 fatty acid supplementation on albuminuria, blood pressure, pulse wave velocity, and inflammatory markers in patients with CKD.

METHODS

Patients with CKD and a urine albumin excretion of at least 30 mg/g creatinine were supplemented for 3 months with 3,666 mg/day of docosahexaenoic and eicosapentaenoic acids or a corn oil supplement. The study was double blind. At baseline, 6 weeks, and 12 weeks, fasting blood and morning spot urine samples were obtained. Blood pressure, carotid intima media thickness, and pulse wave velocity were measured. The main outcome measure was a reduction of ≥20% in urine albumin.

RESULTS

One hundred patients were randomized (50 received omega-3 fatty acids and 50 received corn oil). Four patients who received omega-3 fatty acids and 5 who received vegetable oil were lost to follow-up. In patients receiving omega-3 fatty acids, the omega-3 index increased from 3.08 (2.32-3.81) to 5.48 (3.045-7.04) percent. A 20% reduction in urine albumin excretion was observed in 13 participants of the control group and 19 participants of omega-3 group (Fisher's exact P = .274). However, the supplement had a significant and positive effect on pulse wave velocity and triglyceride level.

CONCLUSION

An omega-3 fatty acid supplement of 3,666 mg/day did not modify urine albumin excretion in patients with CKD but did improve pulse wave velocity and serum triglyceride levels.