Diabetes mellitus, aortic stiffness, and cardiovascular mortality in end-stage renal disease

Arterial Stiffness and its Impact on Cardiovascular Health

PURPOSE OF REVIEW

Cardiovascular diseases are the leading cause of mortality globally. Identifying patients at risk is important to initiate preventive strategies. Over the last few decades, the role of the endothelium and its impact on arterial stiffness have been recognised as playing a pivotal role in cardiovascular disease. This review will focus on the effect of arterial stiffness in different patient cohorts with regard to cardiovascular morbidity and mortality, as well as its use in clinical practice.

RECENT FINDINGS

Arterial stiffness is associated with a range of cardiovascular risk factors and is an independent predictor of cardiovascular mortality. The gold standard for evaluating arterial stiffness is pulse wave velocity. Recently, cardio-ankle vascular index has been implemented as an easy and highly reproducible measure of arterial stiffness. Moreover, certain pharmacologic agents may modify arterial stiffness and alter progression of cardiovascular disease. The endothelium plays an important role in cardiovascular disease. Implementing assessment of arterial stiffness in clinical practice will improve stratification of patients at risk of cardiovascular disease and help modify disease progression.

Interpolation time-optimized aortic pulse wave velocity estimation by 4D flow MRI

Four-dimensional flow magnetic resonance imaging-based pulse wave velocity (4D flow PWV) estimation is a promising tool for measuring regional aortic stiffness for non-invasive cardiovascular disease screening. However, the effect of variations in the shape of flow waveforms on 4D flow PWV measurements remains unclear. In this study, 4D flow PWV values were compared using cross-correlation algorithm with different interpolation times (iTs) based on flow rate and beat frequency. A critical iT (iTCrit) was proposed from in vitro study using flexible and stiff phantom models to simultaneously achieve a low difference and a low computation time. In vivo 4D flow PWV values from six healthy volunteers were also compared between iTCrit and the conventionally used interpolation time of 1 ms (iT1 ms). The results indicated that iTCrit reduced the mean difference of in vitro 4D flow PWV values by 19%, compared to iT1 ms. In addition, iTCrit measured in vivo 4D flow PWV, showing differences similar to those obtained with iT1 ms. A difference estimation model was proposed to retrospectively estimate potential differences of 4D flow PWV using known values of PWV and the used iT. This study would be helpful for understanding the differences of PWV generated by physiological changes and time step of obtained flow waveforms.

[Renal insufficiency and cardiovascular risk]

Patients with chronic renal insufficiency often show symptoms that are atypical for cardiovascular problems. The correct interpretation of the symptoms is crucial in order to correctly assess the risk of a heart-related emergency and to take preventive measures and initiate the right therapy. Biomarkers such as NT-proBNP, troponin T or hsCRP (highly sensitive CRP) are independent predictors of mortality, but do not replace instrument-based diagnostics. Patients with renal insufficiency often have stiff vessels which, due to the premature reflection of the pulse wave, can lead to left ventricular dysfunction and ultimately to heart failure.

Association between zinc deficiency and aorta stiffness in non-diabetic hemodialysis patients

OBJECTIVES

Zinc deficiency (Zn < 60 μg/dL) is known to play an important role for vascular calcification. However, little data is available regarding the association between zinc deficiency and aorta stiffness in dialysis patients. Thus, we studied the relationship between zinc deficiency and aorta stiffness in non-diabetic hemodialysis (HD) patients.

METHODS

Of 150 patients receiving maintenance HD at our hospital, we included 79 non-diabetic HD patients (age: 70±11 years, 49 men) after excluding 71 diabetic HD patients. Zinc deficiency was defined as Zn <60 μg/dL during pre-HD blood sampling. The association between zinc deficiency and aorta stiffness was analyzed. Aorta stiffness was evaluated as brachial-ankle pulse wave velocity (baPWV). Other surrogate markers for cardiovascular complications were also measured.

RESULTS

The zinc deficiency group (ZD group) included 45 patients (57.0%). Compared to the zinc non-deficiency group (ZND group), patients with ZD group were significantly older, higher levels of CRP and hypoalbuminemia. Moreover, they had significantly higher levels of baPWV, and lower levels of ankle-brachial pressure index (ABI) (p<0.05). After adjusting for hypoalbuminemia, and CRP, multivariate analysis showed that age and zinc level were independent predictors of baPWV.

CONCLUSION

The study suggested that zinc deficiency may be an independent risk factor for aorta stiffness, even after adjusting for malnutrition and inflammation.

The association between baseline circulating progenitor cells and vascular function: The role of aging and risk factors

BACKGROUND

To investigate the cross-sectional and longitudinal relationships between vascular function and circulating progenitor cell (CPC) counts with respect to aging and exposure to risk factors.

METHODS

In 797 adult participants, CPCs were enumerated by flow cytometry as CD45med mononuclear cells expressing CD34 epitope and its subsets co-expressing CD133, and chemokine C-X-C motif receptor 4 (CXCR4+). Arterial stiffness was evaluated by tonometry-derived pulse wave velocity (PWV) and microvascular function was assessed as digital reactive hyperemia index (RHI).

RESULTS

In cross-sectional analyses, for every doubling in CD34+ cell counts, PWV was 15% higher and RHI was 9% lower, after adjusting for baseline characteristics and risk factors (p for all < 0.01). There were significant CPC-by-age-by-risk factor interactions (p <0.05) for both vascular measures. Among younger subjects (< 48 years), CPC counts were higher in those with risk factors and vascular function was better in those with higher compared to those with lower CPC counts (p for all < 0.0l). In contrast, in older participants, CPCs were not higher in those with risk factors, and vascular function was worse compared to the younger age group. A lower CPC count at baseline was an independent predictor of worsening vascular function during 2-year follow-up.

CONCLUSION

A higher CPC count in the presence of risk factors is associated with better vascular function among younger individuals. There is no increase in CPC count with risk factors in older individuals who have worse vascular function. Moreover, a higher CPC count is associated with less vascular dysfunction with aging.

Transplantation of bone marrow cells from miR150 knockout mice improves senescence-associated humoral immune dysfunction and arterial stiffness

BACKGROUND AND PURPOSE

The senescence-accelerated mouse P1 (SAMP1) suffers from humoral immune deficiency, arterial stiffness and accelerated aging. In contrast, the microRNA-150 knockout (miR-150-KO) mice show enhanced humoral immune function including increased B cell population and elevated serum immunoglobulin levels and enjoy extended lifespan. The purpose of this study was to investigate whether transplantation of bone marrow cells (BMCs) from miR-150-KO mice affects immune deficiency and arterial stiffening in SAMP1 mice.

METHODS AND RESULTS

Pulse wave velocity and blood pressure were increased significantly in SAMP1 mice (10 months), indicating arterial stiffening and hypertension. Interestingly, transplantation of BMCs from miR-150-KO mice significantly attenuated arterial stiffening and hypertension in SAMP1 mice within eight weeks. BMC transplantation from miR-150-KO mice partially rescued the downregulation of B lymphocytes, largely restored serum IgG and IgM levels, decreased inflammatory cytokine and chemokine expression, and attenuated macrophage and T cell infiltration in aortas in SAMP1 mice. BMC transplantation nearly abolished the upregulation of collagen 1, TGFβ1, Scleraxis, MMP-2 and MMP-9 expression and the downregulation of elastin levels in aortas in SAMP1 mice. FISH staining confirmed existence of the transplanted BMCs at end of the experiment. In cultured endothelial cells, IgG-deficient medium invoked upregulation of inflammatory cytokine/chemokine expression which can be rescued by treatment with IgG.

CONCLUSIONS

Accelerated senescence caused arterial stiffening via impairing the humoral immune function in SAMP1 mice. BMC transplantation from miR-150-KO mice attenuated arterial matrix remodeling and stiffening and hypertension in SAMP1 mice partly via improving the humoral immune function which attenuates vascular inflammation.

Diabetes mellitus type 2 does not influence carotid stiffness in patients on maintenance hemodialysis

Patients on maintenance hemodialysis are a group with high cardiovascular risk, characterized by high arterial stiffness, which is considered a novel cardiovascular risk factor. Diabetes mellitus is both one of the leading causes of end-stage renal disease and a determinant of poor outcome in this group. The aim of the study was to examine carotid stiffness with high resolution echo-tracking in order to assess the influence of diabetes mellitus on arterial stiffness in this group.

Ninety patients (47 F; 43 M) with end-stage renal disease on maintenance hemodialysis were divided into two subgroups: diabetic and nondiabetic (37 and 53 patients respectively). They underwent clinical examination, laboratory tests, and ultrasonographic carotid stiffness assessment both before and after hemodialysis. Local arterial stiffness parameters β, Ep, AC, and PWVβ were calculated. Patient survival was assessed after a 58-month-long follow-up. During the 58-month period 25 of these diabetic patients died, as did 18 non-diabetic patients. Diabetes mellitus was a risk factor for overall mortality among the group of hemodialysed patients. Patients who died from non-cardiovascular causes significantly more often suffered from diabetes mellitus than survivors. There were no statistically significant differences in local arterial stiffness between the groups.

Local arterial stiffness in hemodialysed patients, assessed with high resolution echo-tracking, is not influenced by the presence of diabetes.

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.

Arterial Stiffness as a Cardiovascular Risk Factor for the Development of Preeclampsia and Pharmacopreventive Options

Arterial stiffness (AS) describes the rigidity of the arterial walls. Epidemiological studies have shown that increased AS is an independent predictive marker of cardiovascular (CV) morbidity and mortality in both pregnant and non-pregnant women. Preeclampsia (PE), a form of pregnancy-induced hypertension, affects approximately 5% of pregnancies worldwide. Preeclamptic women have a higher risk of CV disease (CVD), mainly because PE damages the heart's ability to relax between contractions. Different pharmacological approaches for the prevention of PE have been tested in clinical trials (e.g. aspirin, enoxaparin, metformin, pravastatin, and sildenafil citrate). In current clinical practice, only low-dose aspirin is used for PE pharmacoprevention. However, low-dose aspirin does not prevent term PE, which is the most common form of PE. Compromised vascular integrity precedes the onset of PE and therefore, AS assessment may constitute a promising predictive marker of PE. Several non-invasive techniques have been developed to assess AS. Compared with normotensive pregnancies, both carotid-femoral pulse wave velocity (cfPWV) and augmentation index (AIx) are increased in PE. In view of simplicity, reliability, and reproducibility, there is an interest in oscillometric AS measurements in pregnancies complicated by PE.

Pulse Wave Velocity Assessment for Cardiovascular Risk Prognostication in ESKD: Weighting Recent Evidence

BACKGROUND

Among patients with end-stage kidney disease (ESKD), arterial stiffness is considered as a powerful predictor of cardiovascular (CV) morbidity and mortality. However, the relevance of aortic pulse wave velocity (PWV) as a prognostic biomarker for CV risk estimation is not yet fully clear.

METHODS

We performed a systematic search of Medline/PubMed database from inception through August 21, 2019 to identify observational cohort studies conducted in ESKD patients and exploring the association of PWV with CV events and mortality.

RESULTS

Whereas "historical" cohort studies showed aortic PWV to be associated with higher risk of CV and all-cause mortality, recent studies failed to reproduce the independent predictive value of aortic PWV in older ESKD patients. Studies using state-of-the-art prognostic tests showed that the addition of aortic PWV to standard clinical risk scores could only modestly improve CV risk reclassification. Studies associating improvement in PWV in response to blood pressure (BP)-lowering with improvement in survival cannot demonstrate direct cause-and-effect associations due to their observational design and absence of accurate methodology to assess the BP burden.

CONCLUSION

Despite the strong pathophysiological relevance of arterial stiffness as a mediator of CV disease in ESKD, the assessment of aortic PWV for CV risk stratification in this population appears to be of limited value. Whether aortic PWV assessment is valuable in guiding CV risk factor management and whether such a therapeutic approach is translated into improvement in clinical outcomes, is an issue of clinical relevance that warrants investigation in properly-designed randomized trials.

PTH suppression by calcitriol does not predict off-target actions in experimental CKD

Vitamin D receptor agonist (VDRA) therapy for PTH suppression is a mainstay for patients with severe CKD. Calcitriol (1,25‐(OH)₂D₃) is a former first‐line VDRA in CKD treatment. However, a consequence of its use in CKD is accelerated vascular calcification (VC). An experimental CKD model was used to determine whether altering the calcitriol delivery profile to obtain different PTH suppression levels could improve vascular health outcomes. High adenine diet (0.25%) was used to generate experimental CKD in rats. CKD rats were treated using different calcitriol dosing strategies: (a) 20 ng/kg SD (n = 8), (b) 80 ng/kg SD (n = 8), (c) 5 ng/kg QID (n = 9), or (d) 20 ng/kg QID (n = 9). Multiple targets of calcitriol were assessed which include arterial calcium and phosphate as well as circulating calcium, phosphate, PTH, FGF‐23, VWF, and vitamin D metabolome. PTH suppression occurred dose‐dependently after 1‐week calcitriol treatment (P < .01), but the suppressive effect was lost over time. Both VC and circulating FGF‐23 increased > 10× in all calcitriol‐treated rats (P < .05 and P < .001, respectively); similarly, circulating VWF increased at all time points (P < .05). Ad‐hoc analysis of CKD morbidities in treated rats indicated no differences in negative outcomes based on PTH suppression level (minimal‐, target‐, and over‐). Comparing different calcitriol dosing strategies revealed the following: (a) despite initial calcitriol‐influenced PTH suppression across all treatments, the ability to continually suppress PTH was markedly reduced by study conclusion and (b) PTH suppression level is not an adequate proxy for improvements in overall CKD morbidity. These findings show (a) a more holistic approach to evaluate CKD treatment efficacy aside from PTH suppression is needed and (b) that other VDRA therapies should be examined in CKD treatment.

Pilot study of contrast-free MRI reveals significantly impaired calf skeletal muscle perfusion in diabetes with incompressible peripheral arteries

Patients with diabetes mellitus (DM) are more likely to have densely calcified lesions in the below-the-knee tibial arteries. However, the relationship between peripheral arterial calcification and local skeletal muscle perfusion has not been explored. Thirty subjects were prospectively recruited into three groups in this pilot study: (1) Non-DM: 10 people without DM; (2) DM, ABI < 1.3: 10 people with DM and normal ankle-brachial index (ABI) (0.9-1.3); and (3) DM, ABI ⩾ 1.3: 10 people with DM and ABI ⩾ 1.3. All subjects underwent calf perfusion measurements at rest and during an isometric plantarflexion contraction exercise within the magnetic resonance imaging (MRI) system. The noncontrast MRI techniques were applied to quantitatively assess skeletal muscle blood flow (SMBF) and oxygen extraction fraction (SMOEF) in medial gastrocnemius and soleus muscles. Both SMBF and SMOEF reserves were calculated as the ratio of the exercise value to the resting value. Exercise SMBF and SMOEF values in the medial gastrocnemius muscle were lower in the two DM groups than in the non-DM group (p < 0.05). The SMBF reserve in medial gastrocnemius was significantly lower in the DM, ABI ⩾ 1.3 group compared to the DM, ABI < 1.3 group (p < 0.05). This study demonstrates that people with DM and calcified arteries had lower perfusion in gastrocnemius muscle compared to those without DM and those with DM and a normal ABI.

Positive Associations between Adipocyte Fatty Acid-Binding Protein Level and Central Arterial Stiffness in Peritoneal Dialysis Patients

Background

Adipocyte fatty acid-binding protein (A-FABP) plays essential roles in lipolysis, insulin resistance, and atherosclerosis. This study aimed to evaluate the relationship between serum A-FABP levels and carotid-femoral pulse wave velocity (cfPWV) in peritoneal dialysis (PD) patients.

Methods

This study obtained fasting blood samples from 76 PD patients. A validated tonometry system was used to measure cfPWV. Patients with cfPWV values >10 m/s were classified into the high arterial stiffness group, whereas patients with values ≤10 m/s were classified into the low arterial stiffness group, according to the ESH-ESC 2013 guidelines. Serum A-FABP levels were measured using a commercial enzyme-linked immunosorbent assay kit.

Results

Twenty-five (32.9%) of the 76 PD patients were classified in the high arterial stiffness group. Compared with the patients in the low arterial stiffness group, the high arterial stiffness group was older (P = 0.002) and had a longer PD vintage (P = 0.011), higher diastolic blood pressure (DBP, P = 0.036), higher fasting glucose levels (P = 0.012), higher serum C reactive protein levels (P = 0.001), and higher serum A-FABP levels (P < 0.001). A multivariate logistic regression analysis of the factors significantly associated with central arterial stiffness revealed that A-FABP (odds ratio (OR): 1.165, 95% confidence interval (CI): 1.056–1.284, P = 0.002), age (OR: 1.423, 95% CI: 1.153–1.757, P = 0.001), PD vintage (OR: 1.049, 95% CI: 1.015–1.085, P = 0.005), and DBP (OR: 1.152, 95% CI: 1.033–1.285, P = 0.011) were independent predictors of central arterial stiffness in PD patients. Furthermore, serum A-FABP levels (β = 0.476, adjusted R² change: 0.197, P < 0.001) were significantly positively correlated with cfPWV according to the multivariable forward stepwise linear regression analysis.

Conclusions

A-FABP levels are an independent marker of central arterial stiffness in PD patients.

Regional functional and structural abnormalities within the aorta as a potential driver of vascular disease in metabolic syndrome

NEW FINDINGS

What is the central question of this study? Is aortic dysfunction, a significant contributor to cardiovascular disease in metabolic syndrome, expressed uniformly across both the thoracic and abdominal aorta? What is the main finding and its importance? Our study shows that, in the setting of metabolic syndrome, functional and structural deficits in the aorta are differentially expressed along its length, with the abdominal portion displaying more extensive vascular abnormalities. It is, therefore, likely that early interventional strategies targeting the abdominal aorta might alleviate cardiovascular pathologies driven by the metabolic syndrome.

ABSTRACT

The extent of vascular dysfunction associated with metabolic syndrome might vary along the length of the aorta. In this study, we investigated regional functional and structural changes in the thoracic and abdominal aorta of a rat model of metabolic syndrome, namely, high-fat diet (HFD) streptozotocin-induced diabetes mellitus (HFD-D). Four-week-old male Wistar albino rats were fed with either HFD or control diet (CD) for 10 weeks. At week 6, 40 mg/kg streptozotocin and its vehicle were injected i.p. into HFD and CD groups, respectively. At the end of the feeding period, rats were euthanised and aortic segments collected for assessment of vascular functional responses and histomorphometry. Tail-cuff systolic blood pressures (154 ± 6  vs. 110 ± 4 mmHg) and areas under the curve for oral glucose and i.p. insulin tolerance tests were greater in HFD-D versus CD rats. Abdominal aortic vasoconstriction in response to noradrenaline and KCl was greater in HFD-D compared with CD rats. Thoracic vasoconstrictor responses to noradrenaline, but not KCl, were greater in the HFD-D group. Abdominal, but not thoracic, endothelium-dependent vasorelaxation in response to acetylcholine was blunted in HFD-D relative to CD rats; however, nitric oxide-dependent vasorelaxation in HFD-D rats was impaired in both thoracic and abdominal segments. The abdominal aorta of HFD-D rats showed deranged interlamellar spacing and increased lipid plaque deposition. In conclusion, vascular dysfunction in metabolic syndrome is expressed differentially along the length of the aorta, with the abdominal aorta exhibiting increased susceptibility to vasoconstrictors and greater deficits in endothelium-dependent relaxation. These vascular functional abnormalities could potentially underlie the development of hypertensive cardiovascular disease associated with the metabolic syndrome.

The effects of mutation and modification on the structure and stability of human lysozyme: A molecular link between carbamylation and atherosclerosis

Amino acid mutations in some proteins such as lysozyme lead to genetically disorder variants and adverse pathogenic consequences. Recently, amino acid modifications were known as a risk factor in many related diseases such as uremia and atherosclerosis, showing the importance of these surface-structure changes. Although the structural consequences of the hereditary proteins have been examined extensively, such effects for the protein modifications are known to a lesser extent. One drawback in the examination of protein modifications is hardness in experimental detection of modifications by techniques such as NMR and crystallography. Molecular modeling and simulation can help to understand such phenomena at the molecular levels. It is more rational that the effects of both mutation and modification can be compared in a single protein model. Here, molecular dynamics simulation is used to compare the effects of a disease-related carbamylation modification and an amyloidogenic mutation (D67H) in human lysozyme as a model protein. The results show that the carbamylation adversely effects on the tertiary structure, leading to the similar unfolding pathway to the hereditary amyloidogenic form. The carbamylation leads to the instability of the overall protein conformation, especially on the β-domain, which is a characteristic of hereditary amyloidosis in human lysozymes. The aggregation behaviors of both modified and mutant lysozyme were examined by molecular docking calculations. The results showed that the partially unfolded lysozyme might form tight protein aggregates upon carbamylation similar to the amyloidogenic variant. Both single and all-residues carbamylations impose serious conformational changes to the tertiary structure of lysozyme. It was obtained that carbamylation of lysozyme strongly effects on the stability of N-terminal β-sheet, which can produce a highly unstable conformation. The results of this study not only show the adverse structural consequences of a disease-associated post-translational modification, but it also may be very helpful to understand the molecular basis for many carbamylation-related diseases such as atherosclerosis in ESRD patients. The results show that non-native post-translational modifications may be as structurally important as hereditary mutations.

Oxidative Stress and Inflammation as Predictors of Mortality and Cardiovascular Events in Hemodialysis Patients: The DREAM Cohort

Aim: Both oxidative stress and inflammation are involved in the pathogenesis of cardiovascular disease (CVD). The serum level of derivatives of reactive oxygen metabolites (d-ROMs) is a measure of the total amount of hydroperoxides serving as a marker of oxidative stress. We investigated whether d-ROMs could predict the clinical outcomes in hemodialysis patients and whether the associations of d-ROMs with the outcomes are independent of a marker of inflammation, C-reactive protein (CRP).

Methods: This was a prospective cohort study in hemodialysis patients. The key exposures were the serum levels of d-ROMs and CRP. The outcome measures were all-cause mortality and new CVD events.

Results: A total of 517 patients were analyzed. d-ROMs correlated positively with CRP. During follow-up for 5 years, 107 patients died, and 190 patients experienced new CVD events. In the Kaplan–Meier analyses, both higher d-ROMs and higher CRP levels predicted higher risks for mortality and CVD events. By Cox proportional-hazard regression analysis adjusted for potential confounders excluding CRP, d-ROMs exhibited a significant association with all-cause mortality, but this association was no longer significant after further adjustment for CRP. Using the same model, CRP exhibited a significant association with all-cause mortality, but this association was no longer significant after further adjustment for d-ROMs. When we analyzed new CVD events as the outcome, CRP was a significant predictor, whereas the level of d-ROMs was not.

Conclusions: Although d-ROMs predicted mortality and CVD events in unadjusted models, the associations of d-ROMs with these outcomes were not independent of CRP. Oxidative stress and inflammation appear to share common causal pathways.

Arterial Stiffness and Blood Pressure in Patients Newly Diagnosed with Graves' Disease Compared with Euthyroid Controls

INTRODUCTION AND OBJECTIVE

The excess cardiovascular morbidity and mortality in hyperthyroidism and Graves' disease (GD) is inadequately understood. We aimed to elucidate whether well-established cardiovascular risk factors such as arterial stiffness in terms of pulse wave velocity (PWV) and blood pressure differ in GD and controls.

METHODS

This was a cross-sectional study comparing 55 hyperthyroid patients with newly diagnosed GD and 55 euthyroid, population-based controls matched for age, sex and menopausal status. PWV and blood pressure were measured in office (SphygmoCor Xcel) and 24-h ambulatory settings (Arteriograph). Differences between groups were assessed using adjusted linear regression analysis.

RESULTS

Compared to controls, GD patients showed higher PWV in the 24-h but not in the office setting with an adjusted 24-h PWV difference of 1.0 (95% CI: 0.6-1.5) m/s. PWV was higher in GD at both day and night, and nightly PWV dipping was lower (-5.5, 95% CI: -10.4 to -0.6%). Furthermore, central and brachial pulse pressure was significantly higher in both the office and 24-h setting, whereas nightly central pulse pressure dipping was significantly lower in GD (-5.4, 95% CI: -10.5 to -0.2%). Mean arterial pressure did not differ between the groups.

CONCLUSIONS

Despite comparable blood pressure, GD is associated with a higher 24-h PWV that was not detected in the office setting. Pulse pressure was higher in GD, whereas mean arterial pressure did not differ between the groups. Longitudinal studies should pursue whether higher PWV might be a piece to the puzzle of understanding the increased risk of cardiovascular disease in hyperthyroidism and GD.

The Influence of Dialytic Modality on Arterial Stiffness, Pulse Wave Reflections, and Vasomotor Function

Background

Measurements of aortic stiffness [aortic pulse wave velocity (PWV) and augmentation index (AIx)] have been established as powerful predictors of survival on hemodialysis (HD). Abnormal endothelial-dependent and endothelial-independent vascular reactivity and increased arterial stiffness are commonly described in HD patients. There is, however, a lack of information on the comparative impact of different renal replacement therapies (RRTs) on PWV and AIx, and how these different methods might influence endothelial-dependent abnormal vasodilatation.

Objective

To describe in a cross-sectional design arterial compliance and distensibility in continuous ambulatory peritoneal dialysis (CAPD) versus HD versus renal transplant (RTx) patients, compared with age- and blood pressure-matched essential hypertensive controls. The PWV and aortic AIx were determined from contour analysis of arterial waveforms recorded by applanation tonometry in 40 CAPD, 41 HD, 20 RTx patients (with normal serum creatinine), and 20 controls with essential hypertension (all normotensive under treatment). Endothelial-dependent and endothelial-independent vascular reactivities were assessed by changes in AIx following challenges with inhaled salbutamol and sublingual nitroglycerin respectively.

Results

CAPD patients had significantly stiffer arteries than all other categories. The PWV was 8.29 ± 1.09 m/second in CAPD patients, significantly higher ( p < 0.05) compared to HD subjects (7.19 ± 1.87 m/s). Both dialysis subgroups had significantly higher PWV values compared to RTx patients (6.59 ± 1.62 m/s) and essential hypertensive controls (6.34 ± 1.32 m/s), p < 0.05. The AIx had a profile similar to PWV in different RRTs. All groups with the exception of CAPD subjects had a significant decrease in AIx following salbutamol. Moreover, the vasodilatation induced by either nitroglycerin or salbutamol was significantly blunted compared to HD. Overall, both dialysis categories had more abnormal responses compared to RTx patients and essential hypertensive controls.

Conclusion

CAPD is associated with stiffer arteries and more profoundly abnormal endothelial-dependent vasomotor function, compared to matched HD subjects. These differences in arterial physical properties might explain differences seen in cardiac structure and function between the RRTs.

Application of Non-invasive Imaging in Inflammatory Disease Conditions to Evaluate Subclinical Coronary Artery Disease

PURPOSE OF REVIEW

Traditional risk models, such as the Framingham risk score, fail to capture the increased cardiovascular disease risk seen in patients with chronic inflammatory diseases. This review will cover imaging modalities and their emerging applications in assessing subclinical cardiovascular disease for both research and clinical care in patients with chronic inflammatory diseases.

RECENT FINDINGS

Multiple imaging modalities have been studied to assess for subclinical cardiovascular disease via functional/physiologic, inflammatory, and anatomic assessment in patients with chronic inflammatory diseases. The use of imaging to evaluate subclinical cardiovascular disease in patients with chronic inflammatory diseases has the potential to capture early sub-clinical atherosclerosis, to improve risk stratification of future cardiovascular events, and to guide effective disease management.

Characterising recovery from renal transplantation and live-related donation using cardiopulmonary exercise testing

BACKGROUND

An association between end-stage renal failure and exercise intolerance exists. Whether live kidney donation impacts on exercise tolerance is unknown. Here recovery post renal transplant and donation using cardiopulmonary exercise testing is investigated.

METHODS

Renal donors (n = 28) and recipients (n = 24) undertook a cardiopulmonary exercise test, Duke activity score index and patient reported health score questionnaires pre-operatively and in the 7th and 14th week post-operatively. Anaerobic threshold, peak oxygen uptake and ventilatory equivalents were measured in relation to activity and reported health scores. Haemoglobin and renal function was recorded.

RESULTS

Recipients showed impaired cardiopulmonary function compared to donors with lower anaerobic threshold (10.5 vs. 14.4 ml/kg/min) and peak oxygen uptake (18.5 vs 23.0 ml/kg/min). Post-operatively the anaerobic threshold of recipients improved and normalised by the 14th week, whereas that in donors fell by ∼20% by the 7th (mean 11.4 ml/kg/min), recovering by the 14th (mean 15.6 ml/kg/min). Reported health but not activity scores showed similar changes.

CONCLUSIONS

Recovery following renal transplantation and donation differ. Transplantation improves renal function resulting in an increase in anaerobic threshold and peak oxygen uptake which essentially normalise by the 14th week post-operatively. Donors suffer a 20% reduction in cardiopulmonary reserve post-operatively, which recovers by the 14th week, suggesting no associated chronic exercise intolerance.IMPLICATIONS FOR REHABILITATIONCardiopulmonary exercise testing is a real-time predictor of functional capacity and thus is used as a pre-operative tool to measure physiological fitness and predict outcomes.Renal failure is associated with exercise intolerance and transplantation is transformational in terms of quality of life, longevity and healthcare cost.Live - related renal donation is increasingly available but whether donation itself carries a long-term health burden has not been previously well established.This study suggests that renal donation is not associated with long-term cardiopulmonary compromise and patients who donate their kidneys recover their previous fitness within 14 weeks.

Aortic distensibility is associated with both resting and hyperemic coronary blood flow

A large body of evidence demonstrates an independent association between arterial stiffness and prospective risk of cardiovascular events. A reduction in coronary perfusion is presumed to underscore this association; however, studies confirming this are lacking. This study compared invasive measures of coronary blood flow (CBF) with cardiac magnetic resonance (CMR)-derived aortic distensibility (AD). Following coronary angiography, a Doppler FloWire and infusion microcatheter were advanced into the study vessel. Average peak velocity (APV) was acquired at baseline and following intracoronary adenosine to derive coronary flow velocity reserve (CFVR = hyperemic APV/resting APV) and CBF [π × (diameter)2 × APV × 0.125]. Following angiography, patients underwent CMR to evaluate distensibility at the ascending aorta (AA), proximal descending aorta (PDA) and distal descending aorta (DDA). Fifteen participants (53 ± 13 yr) with minor epicardial disease (maximum stenosis <30%) were enrolled. Resting CBF was 44.1 ± 11.9 mL/min, hyperemic CBF was 143.8 ± 37.4 mL/min, and CFVR was 3.15 ± 0.48. AD was 3.89 ± 1.72·10−3mmHg−1 at the AA, 4.08 ± 1.80·10−3mmHg−1 at the PDA, and 4.42 ± 1.67·10−3mmHg−1 at the DDA. All levels of distensibility correlated with resting CBF ( R2 = 0.350–0.373, P < 0.05), hyperemic CBF ( R2 = 0.453–0.464, P < 0.01), and CFVR ( R2 = 0.442–0.511, P < 0.01). This study demonstrates that hyperemic and, to a lesser extent resting CBF, are significantly associated with measures of aortic stiffness in patients with only minor angiographic disease. These findings provide further in vivo support for the observed prognostic capacity of large artery function in cardiovascular event prediction.

NEW & NOTEWORTHY Cardiac magnetic resonance-derived aortic distensibility is associated with invasive measures of coronary blood flow. Large artery function is more strongly correlated with hyperemic than resting blood flow. Increased stiffness may represent a potential target for novel antianginal medications.

Association of non-invasive measures of subclinical atherosclerosis and arterial stiffness with mortality and major cardiovascular events in chronic kidney disease: systematic review and meta-analysis of cohort studies

Background

Non-invasive cardiovascular disease (CVD) risk prediction, in subclinical stages, aiming to stratify patients and tailor interventions remains an unmet need in chronic kidney disease (CKD). In this meta-analysis, we summarize the association of carotid intima-media thickness (cIMT), coronary artery calcium score (CACS) and pulse wave velocity (PWV) with all-cause mortality, cardiovascular (CV) mortality and CV events in non-dialysis CKD and patients on haemodialysis.

Methods

Systematic review and meta-analysis of prospective cohort studies.

Results

Out of 27 984 records, a total of 45 studies were eligible for quantitative synthesis; 11 for cIMT, 18 for CACS and 16 for PWV involving 2235, 4904 and 5717 patients, respectively. Meta-analysis was possible from pooled data of five cIMT studies (708 subjects), eight CACS studies (862 subjects) and nine PWV studies (1508 subjects). In dialysis patients, cIMT was associated with all-cause mortality [relative risk (RR) per unit increase: 1.08, 95% confidence interval (CI) 1.00-1.17, I ²: 68%] and CV mortality (RR: 1.29, 95% CI 1.14-1.47, I ²: 0%). High versus low CACS was associated with all-cause mortality (RR: 2.51, 95% CI 1.66-3.79, I ²: 5.7%) and CV events (RR: 3.77 95% CI 2.16-6.58, I ²: 20.2%). High versus low PWV was associated with all-cause (RR: 5.34, 95% CI 3.01-9.47, I ²: 0%) and CV mortality (RR: 8.55, 95% CI 4.37-16.73, I ²: 0%). The combined estimated for all-cause mortality per 1 m/s increment unit in PWV was 1.25 (95% CI 1.17-1.34, I ²: 0%) and for CV mortality was 1.24 (95% CI 1.16-1.34, I ²: 15.5%). In non-dialysis patients, CACS was associated with CV events (RR: 4.02, 95% CI 1.57-10.29, I ²: 63.4%). High versus low PWV was associated with all-cause mortality (RR: 2.52, 95% CI 1.40-4.55, I ²: 62.6%).

Conclusions

Non-invasive measures of atherosclerosis and arterial stiffening are associated with all-cause and CV mortality as well as CV events among patients with all stages of CKD. These markers could be considered for the evaluation of CV morbidity and mortality risks. Moreover, the results of this meta-analysis support the study of interventions, with effect on these markers of vascular disease, on long-term CVD outcomes.

Establishing the interchangeability of arterial stiffness but not endothelial function parameters in healthy individuals

Background

Development of instruments capable of detecting early stage vascular disease has increased interest in employing arterial stiffness (e.g. pulse wave velocity (PWV), augmentation index (AIx)) and endothelial dysfunction (e.g. reactive hyperemia index (RHI)) to diagnose atherosclerotic disease before occurrence of a cardiovascular event. However, amongst the equipment designed for this purpose, there is insufficient information regarding each of these parameters to establish appropriate cutoffs to distinguish between healthy and unhealthy blood vessels. To address these limitations, the study was designed to establish the upper arterial stiffness and endothelial function thresholds in a healthy population, by comparing the outputs from different instruments capable of measuring PWV, AIx and RHI.

Methods

A systematic comparison of PWV, AIx and RHI was conducted to determine the inter-relationships between these parameters of vascular functionality. Outputs were obtained non-invasively using three instruments, the VP-1000 (VP), SphygmoCor (SC), and EndoPAT (EP), in 40 apparently healthy males and females.

Results

Correlations were found between the brachial-ankle PWV and radial-ankle PWV (by VP and SC), and PWV (VP) with AIx (SC). The interchangeability of these outputs was demonstrated by the Bland Altman test, making it feasible to extrapolate cut-offs for radial-ankle PWV and AIx equivalent to brachial-ankle PWV that signify healthy vessels. In contrast, RHI showed no association with AIx, suggesting these endothelial and arterial parameters are functionally distinct.

Conclusions

It was concluded that it is possible to compare the vascular function outputs of different instruments and identify healthy from unhealthy vessels, even though the approaches for quantifying the underlying physiological processes may differ. In this way, non-invasive determination of arterial function could be a new paradigm for detecting existing early stage asymptomatic atherosclerotic disease in individuals using techniques that are amenable to the clinical setting.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1167-3) contains supplementary material, which is available to authorized users.

Risk Factors Before Dialysis Predominate as Mortality Predictors in Diabetic Maintenance Dialysis patients

Diabetic patients undergoing maintenance dialysis (MD) have a particularly high mortality rate. Many of the risk factors for mortality have been identified in diabetics who die before reaching end stage renal disease (ESRD), i.e. before dialysis (BD). In addition, many risk factors for mortality have been identified in diabetics after dialysis onset (AD). However, whether in the BD period there are long-term risk factors for AD mortality in diabetics is unknown. We therefore investigated a new concept, i.e. that clinical and biochemical risk factors during the BD stage affect long-term AD mortality. We performed a population based retrospective cohort study, in diabetic CKD patients in a single center in south Israel who initiated MD between the years 2003 and 2015. Clinical and biochemical data 12 months BD and 6 months AD were collected and evaluated for association with mortality AD using Cox’s proportional-hazards model. BD parameters that were found to be significant were adjusted for significant parameters AD, thus generating a “combined” regression model in order to isolate the contribution of BD factors on long term mortality. Six hundred and fifty two diabetic MD patients were included in the final analysis. Four independent BD parameters were found in the multivariate model to significantly predict AD mortality: age, BMI (inversely), pulse pressure (U-shaped) and cardiovascular comorbidity. AD independent risk factors for mortality were age, BMI (inversely) and albumin (inversely). Of note, BD factors remained dominantly significant even after additionally adjusting for AD factors. No association was found between either BD HbA1C levels or BD proteinuria and AD mortality. In diabetics who reach ESRD, BD parameters can predict long term AD mortality. Thus, some of the factors affecting the poor survival of diabetic MD patients appear to begin already in the BD period.

Vascular age is associated with the risk of dialysis or death in chronic kidney disease

AIM

Increased arterial stiffness is associated with progressive renal deterioration and poor clinical outcomes in patients with chronic kidney disease (CKD). Assessment of vascular age as derived from arterial stiffness parameters might be an important clinical marker of cardiovascular risks. The aim of the present study is to evaluate whether the difference (△age) between vascular age and chronological age can predict the risk of reaching dialysis or death in patients with known CKD.

METHODS

This longitudinal study enrolled 94 male Chinese CKD patients, aged 40-62 years. Vascular age was calculated by brachial-ankle pulse wave velocity, and measured by an ankle-brachial index-form device. The study endpoints were the commencement of renal replacement therapy or death.

RESULTS

After a stepwise multivariate analysis, △age was associated independently with increased urine protein-to-creatinine ratio (β = 0.32; P = 0.001) and decreased baseline estimated glomerular filtration rate (β = -0.24; P = 0.008). During a median follow-up period of 62 (interquartile range = 55-66) months, the 4-year cumulative incidence of reaching the study endpoint in patients with △age = 0 and △age > 0 year was 4.9% and 25%, respectively (log-rank test, P = 0.009). Multivariate forward Cox regression analysis identified that higher △age (hazard ratio (HR) = 1.05; P = 0.027), lower baseline estimated glomerular filtration rate (HR = 0.93; P < 0.001), and history of cardiovascular disease (HR = 5.90; P = 0.031) were independently associated with progression to commencement of dialysis or death.

CONCLUSION

Thus, the assessment of the difference between vascular age and chronological age may provide an alternative method to identify CKD patients at a high risk of progression to dialysis or death.

The Hardest Part

Aging has a significant impact not only on every single individual but on society as a whole. Today, people throughout the world exhibit an extended lifespan. Therefore, it becomes increasingly important to develop novel concepts that encourage a modern understanding of the aging process. The concept of healthy aging shifts the perception of aging as a burden towards aging as an opportunity for an extended healthy phase in later life. Morbidity and mortality in the elderly population are greatly defined by a raise in the incidence and prevalence of cardiovascular diseases. Consequently, it is critical to identify risk factors and underlying mechanisms that render the aging (cardio)vascular system prone to disease. In this review, we focus on structural mechanisms of arterial stiffening as a major manifestation of vascular aging and its functional implications for the concept of healthy aging.

Ambulatory blood pressures and central blood pressures are associated with cardiovascular morbidity in adolescent and young adult patients receiving chronic hemodialysis

BACKGROUND

Left ventricular hypertrophy (LVH) and arterial stiffness measured by pulse wave velocity (PWV) are independent predictors of cardiovascular (CV) mortality in adults receiving chronic dialysis. Hypertension strongly associates with elevated left ventricular mass index (LVMI) and PWV, with ambulatory blood pressure monitoring (ABPM), and central blood pressure (CBP) superior to office blood pressures (BP) in predicting CV morbidity. Few studies have described associations of office BP, ABPM, and CBP with LVMI and PWV in adolescent and young adult patients receiving hemodialysis (HD).

METHODS

Cross-sectional study of 22 adolescents and young adults receiving chronic HD. Pre- and post-dialysis office BP and CBP using applanation tonometry were obtained. Twenty-four-hour ABPM was obtained midweek post-dialysis. Pre- and post-dialysis carotid-brachial PWV were obtained same day as BP measurements. Annual echocardiograms for standard care were reviewed for LVH.

RESULTS

Pre-dialysis CBP index correlated with LVMI (r = 0.3, p = 0.04) and PWV (r = 0.48, p = 0.02). Hypertensive patients identified by ABPM had worse LVMI; daytime ABPM systolic BP index correlated with LVMI (r = 0.5, p = 0.02). Office BP was not associated with LVMI; only office diastolic BP was associated with PWV (r = 0.46, p = 0.02). There was no correlation of LVMI or PWV with bone health parameters, anemia, interdialytic weight gain, or residual renal function.

CONCLUSIONS

Ambulatory blood pressure monitoring is superior to casual office BP obtained at time of dialysis in delineating cardiovascular morbidity in adolescent and young adult HD patients. CBP is easily performed and correlates with LVMI and PWV in adolescent and young adult HD patients; however, large-scale normative data is needed.

Serum osteoprotegerin is an independent marker of central arterial stiffness as assessed using carotid-femoral pulse wave velocity in hemodialysis patients: a cross sectional study

Background

Cardiovascular morbidity and mortality are highly prevalent in patients with end-stage renal disease, and osteoprotegerin (OPG) may be an important link between bone loss and vascular calcification. This study was conducted to evaluate the relationship between central arterial stiffness and serum OPG levels in hemodialysis (HD) patients.

Methods

Blood samples were collected from 120 HD patients, and the carotid–femoral pulse wave velocity (cfPWV) value was measured using a validated tonometry system. The cfPWV value of > 10 m/s was used to define the high artery stiffness group. Serum OPG levels were analyzed categorically into tertiles.

Results

Of the 120 HD patients, 53 (44.2%) were defined as the high arterial stiffness group, who had higher values of systolic blood pressure (p = 0.038), serum calcium (p = 0.007), and OPG (p <  0.001) levels and a higher prevalence of diabetes mellitus (DM, p = 0.001). Increasing tertiles of serum OPG levels were significantly associated with greater height (p = 0.011), male gender (p = 0.008), higher cfPWV values (p = 0.020), and lower intact parathyroid hormone (iPTH, p = 0.049) levels. Multivariable linear regression analysis showed that cfPWV value was independently associated with DM (β = 1.83, p = 0.008) and increasing tertiles of serum OPG levels (β = 0.89 and 1.63 for tertile 2 and tertile 3, respectively, p for trend = 0.035) in HD patients. Multivariable logistic regression analysis revealed that, in addition to age, DM, low iPTH levels, and high serum calcium levels, increasing tertiles of serum OPG levels (OR = 5.34 for tertile 2; OR = 7.06 for tertile 3; p for trend = 0.002) were an independent predictor of high arterial stiffness in HD patients. Serum calcium levels positively correlated with cfPWV value only in the highest OPG tertile group (r = 0.408, p = 0.009).

Conclusion

A positive association was detected between serum OPG levels and central arterial stiffness in HD patients, and patients with high serum OPG levels may have greater influence of calcium load on central arterial stiffening.

Ankle-brachial index, arterial stiffness, and biomarkers in the prediction of mortality and outcomes in patients with end-stage kidney disease

BACKGROUND

Although ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) are significant predictors of major adverse cardiovascular event (MACE), their prognostic value in association with biomarkers has not been fully evaluated in patients with end-stage kidney disease (ESKD).

HYPOTHESIS

We hypothesized that ABI/baPWV would provide better prognostic value independent of biomarkers in ESKD patients.

METHODS

This study included 104 ESKD patients treated with maintenance hemodialysis who underwent ABI and baPWV examinations and laboratory tests, including brain-natriuretic peptide, high-sensitive cardiac troponin T (hs-cTnT), and high-sensitive C-reactive protein (hs-CRP). MACE was defined as a composite event of all-cause death, acute coronary syndrome, and stroke.

RESULTS

During a mean follow-up of 3.6 ± 1.7 years, a total of 51 MACE were observed. The independent factors associated with MACE were age >75 years (adjusted hazard ratio [HR], 2.15; P < .05), abnormal ABI (adjusted HR, 2.01; P < .05), left ventricular ejection fraction (LVEF) <50% (adjusted HR, 3.33; P < .001), the upper tertile of hs-cTnT (adjusted HR, 2.77; P < .05), and hs-CRP (HR, 1.96; P < .05). However, baPWV did not remain as an independent predictor of MACE in the entire cohort and also in patients without abnormal ABI. The combination of predictors improves the predictive value of MACE, providing increased HR with 4.00 for abnormal ABI + hs-CRP, 4.42 for abnormal ABI + hs-cTnT, and 7.04 for abnormal ABI + LVEF <50% (all P < .001).

CONCLUSION

Abnormal ABI is a robust predictor of MACE independent of biomarkers and their combination provides better risk stratification compared with a single predictor in ESKD patients.

Arterial stiffness and hypertension status in Afro-Caribbean men

OBJECTIVE

African ancestry individuals are at high risk for hypertensive cardiovascular disease (CVD) and could benefit from early detection of arterial stiffening. We tested the association between the 2017 ACC/AHA hypertension categorizations, which include new blood pressure (BP) cutoffs and a definition for elevated BP, and arterial stiffness in 772 Afro-Caribbean men aged 50+ years (mean 64 years).

METHODS

Arterial stiffness was assessed by brachial-ankle pulse-wave velocity (PWV) using a waveform analyzer. Hypertension groups were based on the 2017 ACC/AHA guidelines and by pharmacologic control status. Multiple linear/logistic regression was used to determine the association of PWV with BP and hypertension.

RESULTS

Mean (SD) PWV was 1609 (298) cm/s and was independently correlated with age, SBP, pulse, diabetes, height, and alcohol intake (all P < 0.02). After adjusting for these, in men aged at least 65 years, those with stage 1 or uncontrolled stage 2 hypertension had significantly greater PWV than all other groups (all P < 0.05). Men with controlled hypertension had similar PWV to those with elevated BP (P = 0.7); however, this was significantly greater than men with normal BP (all P < 0.05). Patterns were similar, but with smaller effect sizes, in men aged less than 65 years (all P < 0.05 except controlled hypertension versus elevated or normal BP were not significant).

CONCLUSION

In these high-risk Afro-Caribbeans: stage 1 hypertension is associated with increased PWV, which supports the new guidelines; and, pharmacologic control appears to partially protect men from increased PWV. Longitudinal studies are needed to determine optimal PWV and timing of antihypertensive treatment for preventing future CVD.

SGLT-2 Inhibition: Novel Therapeutics for Reno-and Cardioprotection in Diabetes Mellitus

BACKGROUND

The sodium glucose co-transporter 2 (SGLT2) is primarily located within S1 of the renal proximal tubule being responsible for approximately 90% of glucose re-uptake in the kidney. Inhibition of SGLT2 is an exciting new pharmacological approach for the reduction of blood glucose in type 2 diabetic patients via inhibition of tubular glucose reabsorption. In addition to lowering glucose, this group of drugs has shown significant cardiovascular and renal protective effects.

CONCLUSION

This review aims to outline the current state of preclinical research and clinical trials for different SGLT2 inhibitors and outline some of the proposed mechanisms of action, including possible effects on sympathetic nerve activity, which may contribute to the unexpected beneficial cardiovascular and reno-protective effects of this class of compounds.

The reproducibility of cardiac magnetic resonance imaging measures of aortic stiffness and their relationship to cardiac structure in prevalent haemodialysis patients

BACKGROUND

Aortic stiffness is one of the earliest signs of cardiovascular disease (CVD) in patients with chronic kidney disease and an independent predictor of mortality. It is thought to drive left ventricular (LV) remodelling, an established biomarker for mortality. The relationship between direct and indirect measures of aortic stiffness and LV remodelling is not defined in dialysis patients, nor are the reproducibility of methods used to assess aortic stiffness using cardiac magnetic resonance (CMR) imaging.

METHODS

Using 3T CMR, we report the results of (i) the interstudy, interobserver and intra-observer reproducibility of ascending aortic distensibility (AAD), descending aortic distensibility (DAD) and aortic pulse wave velocity (aPWV) in 10 haemodialysis (HD) patients and (ii) the relationship between AAD, DAD and aPWV and LV mass index (LVMi) and LV remodelling in 70 HD patients.

RESULTS

Inter- and intra-observer variability of AAD, DAD and aPWV were excellent [intraclass correlation (ICC) > 0.9 for all]. Interstudy reproducibility of AAD was excellent {ICC 0.94 [95% confidence interval (CI) 0.78-0.99]}, but poor for DAD and aPWV [ICC 0.51 (-0.13-0.85) and 0.51 (-0.31-0.89)]. AAD, DAD and aPWV associated with LVMi on univariate analysis (β = -0.244, P = 0.04; β =-0.315, P < 0.001 and β = 0.242, P = 0.04, respectively). Only systolic blood pressure, serum phosphate and a history of CVD remained independent determinants of LVMi on multivariable linear regression.

CONCLUSIONS

AAD is the most reproducible CMR-derived measure of aortic stiffness in HD patients. CMR-derived measures of aortic stiffness were not independent determinants of LVMi in HD patients. Whether one should target blood pressure over aortic stiffness to mitigate cardiovascular risk still needs determination.

Sympathetic overactivity in dialysis patients-Underappreciated and clinically consequential

Cardiovascular morbidity and mortality remain frustratingly common in dialysis patients. A dearth of established evidence-based treatment calls for alternative therapeutic avenues to be embraced. Sympathetic hyperactivity, predominantly due to afferent nerve signaling from the diseased native kidneys, has been established to be prognostic in the dialysis population for over 15 years. Despite this, tangible therapeutic interventions have, to date, been unsuccessful and the outlook for patients remains poor. This narrative review summarizes established experimental and clinical data, highlighting recent developments, and proposes why interventions to ameliorate sympathetic hyperactivity may well be beneficial for this high-risk population.

Arterial Stiffness in Balkan Endemic Nephropathy, an Environmental Form of Aristolochic Acid Nephropathy

Balkan endemic nephropathy (BEN), an environmental form of aristolochic acid nephropathy is characterized with later onset and milder forms of hypertension (HT). Thus, we hypothesized that arterial stiffness progresses slower in BEN patients resulting in lower CV mortality. A total of 186 hemodialysed (HD) patients (90 BEN, 96 non-BEN; 67.3 + 13.0 years) were enrolled and followed-up for 25 months. Brachial blood pressure (BP) and pulse wave velocity (PWV) were determined before mid-week dialysis. BEN patients were older (72.1 ± 37.1 vs. 62.8 ± 15.1; p < 0.001), had shorter duration of HT prior commencement of HD than non-BEN patients (36 vs. 84 months; p < 0.001). There were no differences in BP, but BEN patients were treated with less antihypertensive drugs (p < 0.01). BEN patients had lower PWV values at baseline and at the end of follow-up period despite being chronologically older (p < 0.001). Baseline PWV > 10 m/s was associated with higher risk for CV mortality (aHR 1.8 [1.4, 2.4]). In multivariate analyses BEN was predictor of lower PWV. During the follow-up period significantly less CV deaths were observed in BEN vs. on-BEN patients (12 vs. 31; p = 0.001). CV mortality adjusted for other risk factors was significantly lower in BEN group (aHR 0.2 [0.1, 0.5]). Overall BEN patients had longer mean survival time on HD (22.3 vs. 18.2 months; p < 0.001). Observed slower vascular aging (i.e., lower PWV) in BEN patients compared to other ESRD patients is related to the later onset of HT and milder stages of HT during predialytic clinical course and better control of BP and phosphate during HD.

Improving survival in end-stage renal disease: A case study

Background: With the increase of life expectancy, *On behalf of the REIN registry. end-stage renal disease (ESRD) is affecting a growing number of people. Simultaneously, renal replacement therapies (RRTs) have considerably improved patient survival. We investigated the way current RRT practices would affect patients' survival.

Methods: We used a multi-state model to represent the transitions between RRTs and the transition to death. The concept of “crude probability of death” combined with this model allowed estimating the proportions of ESRD-related and ESRD-unrelated deaths. Estimating the ESRD-related death rate requires comparing the mortality rate between ESRD patients and the general population. Predicting patients' courses through RRTs and Death states could be obtained by solving a system of Kolmogorov differential equations. The impact of practice on patient survival was quantified using the restricted mean survival time (RMST) which was compared with that of healthy subjects with same characteristics.

Results: The crude probability of ESRD-unrelated death was nearly zero in the youngest patients (18–45 years) but was a sizeable part of deaths in the oldest (≥70 years). Moreover, in the oldest patients, the proportion of expected death was higher in patient without vs. with diabetes because the former live older. In men aged 75 years at first RRT, the predicted RMSTs in patients with and without diabetes were, respectively, 61% and 69% those of comparable healthy men.

Conclusion: Using the concept of “crude probability of death” with multi-state models is feasible and useful to assess the relative benefits of various treatments in ESRD and help patient long-term management.

Demonstration of circumferential heterogeneity in displacement and strain in the abdominal aortic wall by spiral cine DENSE MRI

BACKGROUND

Knowledge of tissue properties of the abdominal aorta can improve understanding of vascular disease and guide interventional approaches. Existing MRI methods to quantify aortic wall displacement and strain are unable to discern circumferential heterogeneity.

PURPOSE

To assess regional variation in abdominal aortic wall displacement and strain as a function of circumferential position using spiral cine displacement encoding with stimulated echoes (DENSE).

STUDY TYPE

Prospective.

POPULATION

Cardiovascular disease-free men (n = 8) and women (n = 9) ages 30-42.

SEQUENCES

Prospective electrocardiogram (ECG)-gated and navigator echo-gated spiral, cine 2D DENSE and retrospective ECG-gated phase contrast MR (PCMR) sequences at 3T.

ASSESSMENT

In-plane displacement values of the aortic wall acquired with DENSE were used to determine radial and circumferential aortic wall motion. A quadrilateral-based 2D strain calculation method was implemented to determine strain from the displacement field. Peak displacement and its radial and circumferential contributions as well as peak circumferential strain were compared among eight circumferential wall segments. Distensibility was calculated using PCMR and compared with homogenized circumferential strain.

STATISTICAL TESTS

To account for repeated measurements in volunteers, linear mixed models for mean sector values were created for displacement magnitude, circumferential displacement, radial displacement, and circumferential strain. Comparisons were made between sectors. Calculated distensibility and homogenized circumferential strain were compared using Bland-Altman analysis. Statistical significance was defined as P < 0.05.

RESULTS

Displacement was highest in the anterior wall (1.5 ± 0.7 mm) and was primarily in the radial as compared with circumferential direction (1.04 ± 0.05 mm vs. 0.81 ± 0.42 mm). Circumferential strain was highest in the lateral walls (left 0.16 ± 0.05 and right 0.21 ± 0.12) with homogenized circumferential strain of 0.14 ± 0.05.

DATA CONCLUSION

DENSE imaging in the abdominal aortic wall demonstrated that the anterior aortic wall exhibits the greatest displacement, while the lateral wall experiences the largest circumferential strain.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:731-743.

The Relationship between Inter-Arm Blood Pressure Difference and Coronary Artery Disease Severity Calculated by the SYNTAX Score

Objectives

The inter-arm systolic blood pressure difference (IASBPD) is closely related to cardiovascular mortality and morbidity. The SYNTAX score indicates the extent and complexity of coronary artery disease, which are determined by coronary angiography. The aim of our study is to examine the relationship between the IASBPD (which is easily calculated in routine practice) and the SYNTAX score.

Methods

104 patients were included in this cross-sectional study. The IASBPD was calculated by blood pressure measurements obtained simultaneously from both arms. The SYNTAX score was calculated by coronary angiography.

Results

Patients were divided into two groups: those with a high SYNTAX score (≥20) and those with a low SYNTAX score (<20). The mean IASBPD values were significantly higher in the group with a high SYNTAX score (≥20) (p<0.001). The patients with IASBPD≥10 were more likely to have a high SYNTAX score compared to the patients with IASBPD<10 (p<0.001). Multiple logistic regression analysis revealed that only the IASBPD values were found to be independently associated with high SYNTAX score (OR: 1.717 (CI: 1.307-2.257), p<0.001).

Conclusion

The IASBPD values obtained by only blood pressure measurements are closely related to the extent of coronary artery disease.

Traditional practices and recent advances in Nadi Pariksha: A comprehensive review

The significance of Nadi Pariksha is well understood and effectively used by Ayurveda practioners for assessing Tridoshas and various physiological and psychological states of the patient. The traditional texts Sarangadhara Samhita, YogaRatnakara, Basavarajeeyam and Bhavaprakasha have discussed the details of Nadi Pariksha in succinct set of slokas. Ayurveda has thousands of years of rich experience in Nadi Pariksha with strong literature support but is subjective in nature and the need for studying nadi with a scientific approach is well understood. Recently, pulse wave velocity has gained significant research interest as it is considered to be a strong indicator of cardiovascular disease; however, the relevance of pulse wave analysis to Nadi Pariksha has not been studied. In this review, traditional methods of Nadi Pariksha as defined in Ayurveda classics and the recent advances in pulse wave analysis are discussed. As per classical texts, qualities or properties of pulse such as pulse movement (gati), speed of the pulse (vega), stability of the pulse (sthiratva) and hardness of the artery (kathinya) play major role in Nadi Pariksha and in the current review these properties were analyzed and compared with the modern pulse parameters namely pulse wave velocity, pulse rate variability and arterial stiffness. The significance of pulse wave velocity in cardiovascular studies is discussed and the need for extending these studies to Ayurveda is highlighted.

Volume status and arterial blood pressures are associated with arterial stiffness in hemodialysis patients

BACKGROUND

Arterial stiffness is a strong predictor of mortality in hemodialysis patients. In this study, we aimed to investigate possible relations of arterial stiffness with volume status determined by bioimpedance analysis and aortic blood pressure parameters. Also, effects of a single hemodialysis session on these parameters were studied.

METHODS

A total of 75 hemodialysis patients (M/F: 43/32; mean age: 53 ± 17) were enrolled. Carotid-femoral pulse wave velocity, augmentation index, and aortic pulse pressure were measured by applanation tonometry before and after hemodialysis. Extracellular fluid and total body fluid volumes were determined by bioimpedance analysis.

RESULTS

Carotid-femoral pulse wave velocity (9.30 ± 3.30 vs 7.59 ± 2.66 m/s, p < 0.001), augmentation index (24.52 ± 9.42 vs 20.28 ± 10.19, p < 0.001), and aortic pulse pressure (38 ± 14 vs 29 ± 8 mmHg, p < 0.001) significantly decreased after hemodialysis. Pre-dialysis carotid-femoral pulse wave velocity was associated with age (r² = 0.15, p = 0.01), total cholesterol (r² = 0.06, p = 0.02), peripheral mean blood pressure (r² = 0.10, p = 0.005), aortic-mean blood pressure (r² = 0.06, p = 0.02), aortic pulse pressure (r² = 0.14, p = 0.001), and extracellular fluid/total body fluid (r² = 0.30, p < 0.0001). Pre-dialysis augmentation index was associated with total cholesterol (r² = 0.06, p = 0,02), aortic-mean blood pressure (r² = 0.16, p < 0.001), and aortic pulse pressure (r² = 0.22, p < 0.001). Δcarotid-femoral pulse wave velocity was associated with Δaortic-mean blood pressure (r² = 0.06, p = 0.02) and inversely correlated with baseline carotid-femoral pulse wave velocity (r² = 0.29, p < 0.001). Pre-dialysis Δaugmentation index was significantly associated with Δaortic-mean blood pressure (r² = 0.09, p = 0.009) and Δaortic pulse pressure (r² = 0.06, p = 0.03) and inversely associated with baseline augmentation index (r² = 0.14, p = 0.001). In multiple linear regression analysis (adjusted R² = 0.46, p < 0.001) to determine the factors predicting Log carotid-femoral pulse wave velocity, extracellular fluid/total body fluid and peripheral mean blood pressure significantly predicted Log carotid-femoral pulse wave velocity (p = 0.001 and p = 0.006, respectively).

CONCLUSION

Carotid-femoral pulse wave velocity, augmentation index, and aortic pulse pressure significantly decreased after hemodialysis. Arterial stiffness was associated with both peripheral and aortic blood pressure. Furthermore, reduction in arterial stiffness parameters was related to reduction in aortic blood pressure. Pre-dialysis carotid-femoral pulse wave velocity was associated with volume status determined by bioimpedance analysis. Volume control may improve not only the aortic blood pressure measurements but also arterial stiffness in hemodialysis patients.

Comparison of pulse wave velocity and pulse pressure amplification in association with target organ damage in community-dwelling elderly: The Northern Shanghai Study

This study aimed to investigate the discrepancy between pulse wave velocity (PWV) and pulse pressure amplification (PPA) in association with hypertensive target organ damage (TOD) in the elderly. From June 2014 to August 2015, 1599 participants aged >65 years old from communities located in northern Shanghai were recruited. Carotid-femoral pulse wave velocity (cfPWV), peripheral blood pressure (BP), central BP and other TOD indicators, including the ratio of the early ventricular filling velocity (E) to the peak velocity of the tissue Doppler velocity of septal mitral annulus (E/Ea), left ventricular mass index (LVMI), carotid intima-medium thickness (CIMT), estimated glomerular filtration rate (eGFR), and urinary albumin-creatinine ratio (ACR), were determined for each participant. PPA was defined as the peripheral-to-central pulse pressure ratio. In multivariable linear regression analysis, cfPWV was significantly associated with CIMT (β = 12.83 ± 4.28 μm per SD; P = 0.003) and eGFR (β = -1.85 ± 0.69 ml/min/1.73 m² per SD; P = 0.007), whereas PPA was significantly associated with E/Ea (β = -0.25 ± 0.10 per SD; P = 0.01) and LVMI (β = -3.00 ± 0.78 g/m² per SD; P < 0.001). Similarly, in multivariable logistic regression analysis, cfPWV was significantly associated with arterial plaque (odds ratio [OR], 1.21 [95% confidence interval [CI], 1.05-1.39]; P = 0.007), peripheral artery disease (OR, 1.22 [95% CI, 1.06-1.42]; P = 0.007), chronic kidney diseases (OR, 1.24 [95% CI, 1.01-1.54]; P = 0.04) and microalbuminuria (OR, 1.21 [95% CI, 1.07-1.37]; P = 0.002), while PPA was tightly associated with left ventricular hypertrophy (OR, 0.85 [95% CI, 0.72-0.99]; P = 0.04) and diastolic dysfunction (OR, 0.78 [95% CI, 0.64-0.96]; P = 0.02). In conclusion, cfPWV is a vessel-related and renal-related biomarker, while PPA is a cardiac-related biomarker in community-based elderly.

Arterial stiffness in end-stage renal disease-pathogenesis, clinical epidemiology, and therapeutic potentials

Arterial stiffness is an important risk factor for cardiovascular morbidity and mortality in patients with end-stage renal disease (ESRD). Arterial stiffness aggravates cardiovascular risk via multiple pathways, such as augmentation of aortic systolic pressure, subendocardial hypoperfusion, and excess pulsatile energy transmission from macro- to microcirculation. Pathogenesis of the arteriosclerotic process in ESRD is complex and not yet fully understood. Several factors unique to ESRD, such as mineral metabolism disturbances, vascular calcifications, formation of advanced glycation end-products, and acute and chronic volume overload, are proposed to play a particular role in the progression of arteriosclerosis in ESRD. As these and other mechanistic pathways of arterial stiffening in ESRD are elucidated, there is hope that this knowledge will be translated into novel therapeutic interventions targeting arterial stiffness. In the meantime, blood pressure (BP) lowering via strict volume control and appropriate use of antihypertensive drugs is a fundamental step in reversing accelerated arterial stiffening and modifying the cardiovascular risk profile of ESRD patients. In this article, we review the pathogenesis, clinical epidemiology, and therapies targeting arterial stiffness in ESRD, discussing recent advances and high-priority goals of future research in these important areas.

Gender-specific associations of skeletal muscle mass and arterial stiffness among peritoneal dialysis patients

Decreased skeletal muscle has been identified as a relevant factor for arterial stiffness but has not been thoroughly investigated in peritoneal dialysis (PD) patients. The aim of this study was to investigate the relationship between skeletal muscle and arterial stiffness in PD patients. A cross-sectional study of 658 prevalent PD patients with a mean brachial-ankle pulse wave velocity (baPWV) of 1714 (±501) cm/s and mean skeletal muscle mass of 26.6 (±5.4) kg was performed. Skeletal muscle mass level was significantly higher in males than in females. When examining skeletal muscle mass as a continuous variable, skeletal muscle mass was significantly associated with baPWV in fully adjusted linear regression models in total patients [standardized coefficients (β), −0.181; 95% confidence interval (95% CI), −0.276 to −0.056; P = 0.003] or female patients (β, −0.119; 95% CI, −0.350 to −0.015; P = 0.03) but not in male patients (β, −0.117; 95% CI, −0.300 to 0.011; P = 0.07). Furthermore, in females, a significant association between the middle or highest tertile of skeletal muscle mass and baPWV was found in fully adjusted models (β, −0.123; 95% CI, −0.204 to −0.008; P = 0.03; β, −0.140; 95% CI, −0.228 to −0.016; P = 0.02, respectively). In conclusion, decreased skeletal muscle mass was independently associated with increased baPWV in PD patients, and this association was significant in females but not in males.

Relationship between brachial-ankle and heart-femoral pulse wave velocities and the rapid decline of kidney function

The impact of brachial-ankle pulse wave velocity (baPWV) and heart-femoral pulse wave velocity (hfPWV) on rapid decline of estimated glomerular filtration rate (eGFR) has been inconclusive. The database of a multicenter prospective study of 2238 patients in Korea enrolled from 2011 to 2016 was reviewed. After excluding patients with missing baPWV (n = 257) and eGFR change (n = 180), the study included 1801 non-dialysis chronic kidney disease (CKD) patients. The eGFR change <−5ml/min/1.73 m²/year was defined as rapid decline. During a mean of 2.2 years, the mean eGFR change was −3.6 ml/min/1.73 m²/year, and 31.6% of patients were classified as having rapid decline. Older age, causes of CKD, increased heart rate, systolic blood pressures, and proteinuria were associated with the highest baPWV quintile. In multivariate logistic regression analyses, the odds of a rapid decline in eGFR was 1.9 times higher in the fifth quintile than in the first quintile (P = 0.013). In a subset with baPWV and hfPWV (n = 1182), high baPWV was associated with rapid eGFR decline only when accompanied by a high hfPWV. These findings suggest that central and peripheral PWVs may simultaneously affect rapid eGFR decline.

Reduction of Arterial Stiffness After Kidney Transplantation: A Systematic Review and Meta-Analysis

Background

End‐stage kidney disease is associated with increased arterial stiffness. Although correction of uremia by kidney transplantation (KTx) could improve arterial stiffness, results from clinical studies are unclear partly due to small sample sizes.

Method and Results

We conducted a systematic review and meta‐analysis of before‐after design studies performed in adult KTx patients with available measures of arterial stiffness parameters (pulse wave velocity [PWV], central pulse pressure [PP], and augmentation index) before and at any time post‐KTx. Mean difference of post‐ and pre‐KTx values of different outcomes were estimated using a random effect model with 95% confidence interval. To deal with repetition of measurement within a study, only 1 period of measurement was considered per study by analysis. Twelve studies were included in meta‐analysis, where a significant decrease of overall PWV by 1.20 m/s (95% CI 0.67‐1.73, I²=72%), central PWV by 1.20 m/s (95% CI 0.16‐2.25, I²=83%), peripheral PWV by 1.17 m/s (95% CI 0.17‐2.17, I²=79%), and brachial‐ankle PWV by 1.21 m/s (95% CI 0.66‐1.75, I²=0%) was observed. Central PP (reported in 4 studies) decreased by 4.75 mm Hg (95% CI 0.78–10.28, I²=50%). Augmentation index (reported in 7 studies) decreased by 10.5% (95% CI 6.9‐14.1, I²=64%). A meta‐regression analysis showed that the timing of assessment post‐KTx was the major source of the residual variance.

Conclusions

This meta‐analysis suggests a reduction of the overall arterial stiffness in patients with end‐stage kidney disease after KTx.

Obesity and the risk of cardiovascular and all-cause mortality in chronic kidney disease: a systematic review and meta-analysis

Background

Obesity is a risk factor for cardiovascular disease and death in people without chronic kidney disease (CKD), but the effect of obesity in people with CKD is uncertain.

Methods

Medline and Embase (from inception to January 2015) were searched for cohort studies measuring obesity by body mass index (BMI), waist:hip ratio (WHR) and/or waist circumference (WC) and all-cause and cardiovascular mortality or events in patients with any stage of CKD. Data were summarized using random effects models. Meta-regression was conducted to assess sources of heterogeneity.

Results

Of 4065 potentially eligible citations, 165 studies ( n = 1 534 845 participants) were analyzed. In studies that found a nonlinear relationship, underweight people with CKD (3-5) on hemodialysis experienced an increased risk of death compared with those with normal weight. In transplant recipients, excess risk was observed at levels of morbid obesity (>35 kg/m 2 ). Of studies that found the relationship to be linear, a 1 kg/m 2 increase in BMI was associated with a 3 and 4% reduction in all-cause and cardiovascular mortality in patients on hemodialysis, respectively {adjusted hazard ratio [HR] 0.97 [95% confidence interval (CI) 0.96-0.98] and adjusted HR 0.96 (95% CI 0.92-1.00)}. In CKD Stages 3-5, for every 1 kg/m 2 increase in BMI there was a 1% reduction in all-cause mortality [HR 0.99 (95% CI 0.0.97-1.00)]. There was no apparent association between obesity and mortality in transplanted patients or those on peritoneal dialysis. Sparse data for WHR and WC did not allow further analyses.

Conclusions

Being obese may be protective for all-cause mortality in the predialysis and hemodialysis populations, while being underweight suggests increased risk, but not in transplant recipients.

Color M-mode echocardiography-derived propagation velocity of descending aorta decreases with aging

Background

Arterial stiffness (AS) can be determined by some noninvasive tests such as pulse wave velocity (PWV). Atherosclerosis is also detectable by some ultrasonographic techniques such as color M-mode-derived propagation velocity measured along the origin of the descending aorta (AVP).

Aim

The aim of the study was to find out a possible relationship between atherosclerosis and AVP and whether AVP can be used as a parameter of AS.

Materials and methods

The study group was composed of 134 people from routine screening examination who were ≥40 years old, completely healthy, and without any known disease and use of any drug. PWV has been determined to show aortic stiffness, and carotid artery intima– media thickness (CIMT) was measured for subclinical atherosclerosis. AVP values were obtained from all participants, and correlations were calculated between these parameters and age.

Results

AVP decreased (r=−0.902, P<0.001) and PWV increased (r=0.854, P<0.001) significantly with increasing age. CIMT also increased with aging (r=0.518, P<0.001). There were significant correlations between AVP and PWV (r=−0.832, P<0.001) and AVP and CIMT (r=−0.345, P<0.001).

Conclusion

Transthoracic echocardiographic determination of AVP can be used as a simple measurement of AS and correlates well with PWV, age, and CIMT in healthy people.