Cardiovascular autonomic nervous system dysfunction in chronic kidney disease and end-stage kidney disease: disruption of the complementary forces

New Insights on Cardiac Arrhythmias in Patients With Kidney Disease

The risk of arrhythmia and its management become increasingly complex as kidney disease progresses. This presents a multifaceted clinical challenge. Our discussion addresses these specific challenges relevant to patients as their kidney disease advances. We highlight numerous opportunities for enhancing the current standard of care within this realm. Additionally, this review delves into research concerning early detection, prevention, diagnosis, and treatment of various arrhythmias spanning the spectrum of kidney disease.

Autonomic Neuropathy as a Predictor of Morbidity and Mortality in People Living With HIV: A Retrospective, Longitudinal Cohort Study

Background and Objectives

HIV-associated autonomic neuropathy (HIV-AN) is common; however, its clinical effect is unclear. Previously, it was shown that the composite autonomic severity score is associated with markers of morbidity such as the Veterans Affair Cohort Study index. In addition, it is known that cardiovascular autonomic neuropathy due to diabetes is associated with poor cardiovascular outcomes. This study aimed to evaluate whether HIV-AN is predictive of important adverse clinical outcomes.

Method

The electronic medical records of HIV-infected participants who underwent autonomic function tests at the Mount Sinai Hospital between April 2011 and August 2012 were reviewed. The cohort was stratified into those who had no or mild autonomic neuropathy (HIV-AN [-], CASS ≤3) and those with moderate or severe autonomic neuropathy (HIV-AN [+], CASS >3). The primary outcome was a composite of the incidence of death from any cause, new major cardiovascular or cerebrovascular event, or development of severe renal or hepatic disease. Time-to-event analysis was performed using Kaplan-Meier analysis and multivariate Cox proportional hazards regression models.

Results

One hundred eleven of 114 participants had follow-up data (median follow-up for HIV-AN (-) was 94.00 months, and HIV-AN (+) was 81.29 months) and were included in the analysis. Participants were followed until March 1, 2020. The HIV-AN (+) group (N = 42) was significantly associated with the presence of hypertension, higher HIV-1 viral load, and more abnormal liver function. Seventeen (40.48%) events occurred in the HIV-AN (+) group, and 11 (15.94%) occurred in the HIV-AN (-) group. Six (14.29%) cardiac events occurred in the HIV-AN (+) group, whereas 1 (1.45%) occurred in the HIV-AN (-) group. The other subgroups of the composite outcome had a similar trend. The adjusted Cox proportional hazards model showed that the presence of HIV-AN predicted our composite outcome (HR 3.85, CI 1.61-9.20).

Discussion

These findings suggest that HIV-AN is associated with the development of severe morbidity and mortality in people living with HIV. People living with HIV with autonomic neuropathy may benefit from closer cardiac, renal, and hepatic surveillance.

Sleep traits and risk of end-stage renal disease: a mendelian randomization study

BACKGROUND

Epidemiological evidence relating sleep disorders to end-stage renal disease (ESRD) has been obscure. The present study is sought to examine the association between sleep traits and ESRD.

METHODS

For this analysis, we selected genetic instruments for sleep traits from published genome-wide association studies (GWAS). As instrumental variables, independent genetic variations linked with seven sleep-related features (sleep duration, getting up in the morning, daytime napping, chronotype of morning/evening person, sleeplessness/insomnia, non-snoring, and daytime dozing) were chosen. A two-sample Mendelian randomization (TSMR) study was conducted to assess the causal relationship between sleep traits and ESRD (N = 33,061). The reverse MR analysis subsequently determined the causal relationship between ESRD and sleep traits. The causal effects were estimated using inverse variance weighted, MR-Egger, weighted median. To conduct sensitivity studies, Cochran's Q test, MR-Egger intercept test, MR-PRESSO, leave-one-out analysis, and funnel plot were used. To study the potential mediators, multivariable mendelian randomization analyses were undertaken further.

RESULTS

Genetically predicted sleeplessness/ insomnia (OR = 6.11, 95%CI 1.00-37.3, P = 0.049, FDR = 0.105), getting up in the morning easily(OR = 0.23, 95%CI 0.063-0.85; P = 0.0278, FDR = 0.105), non-snoring (OR = 4.76E-02, 95%CI 2.29E-03-0.985, P = 0.0488, FDR = 0.105) was suggestively associated with the risk of ESRD. However, we found no evidence favoring a causal association between other sleep traits and ESRD through the IVW method.

CONCLUSION

The present TSMR found no strong evidence of a bidirectional causal association between genetically predicted sleep traits and ESRD.

Disparities in efficacy and safety of sodium-glucose cotransporter 2 inhibitor among patients with different extents of renal dysfunction: A systematic review and meta-analysis of randomized controlled trials

Background: The pleiotropic efficacy of SGLT2is in patients with different eGFR levels has not been well-understood. This systematic review and meta-analysis assessed the disparities in the efficacy and safety of SGLT2i treatment across stratified renal function. Methods: We searched four databases from inception to December 2021. We included randomized controlled trials (RCTs) with reported baseline eGFR levels and absolute changes from baseline in at least one of the following outcomes: HbA1c, body weight, blood pressure, and eGFR. Continuous outcomes were evaluated as the weighted mean differences (WMDs) and 95% confidence intervals (CIs). Categorical outcomes were evaluated as odds ratios (ORs) and accompanying 95% CIs. Results: In total, 86 eligible RCTs were included. SGLT2is produces a substantial benefit in glycemic control, weight control, and blood pressure control even in patients with impaired renal function. HbA1c and weight reductions observed in SGLT2i users were generally parallel with the renal function levels, although there was an augmented weight reduction in severe renal dysfunction stratum [HbA1c: -0.49% (-0.58 to -0.39%) for normal renal function, -0.58% (-0.66 to -0.50%) for mild renal function impairment, -0.22% (-0.35 to -0.09%) for moderate renal function impairment, and -0.13% (-0.67 to 0.42%) for severe renal function impairment (p < 0.001 for subgroup differences); weight: -2.12 kg (-2.66 to -1.59 kg) for normal renal function, -2.06 kg (-2.31 to -1.82 kg) for mild renal function impairment; -1.23 kg (-1.59 to -0.86 kg) for moderate renal function impairment; -1.88 kg (-3.04 to -0.72 kg) for severe renal function impairment (p = 0.002 for subgroup differences)]. However, the blood pressure reduction observed in SGLT2i users was independent of renal function. When compared with the placebo, the occurrence of hypoglycemia was more frequent in patients with favorable renal function rather than in those with substantial renal dysfunction. Conclusion: The HbA1c and body weight reductions observed in SGLT2i users were generally parallel with their baseline eGFR levels, while blood pressure reductions in SGLT2i users were independent of their baseline eGFR levels. Consistently, when compared with the placebo, hypoglycemia was more frequent in patients with favorable renal function, where the HbA1c reduction was profound.

Uremic toxins in chronic kidney disease highlight a fundamental gap in understanding their detrimental effects on cardiac electrophysiology and arrhythmogenesis

Chronic kidney disease (CKD) and cardiovascular disease (CVD) have an estimated 700-800 and 523 million cases worldwide, respectively, with CVD being the leading cause of death in CKD patients. The pathophysiological interplay between the heart and kidneys is defined as the cardiorenal syndrome (CRS), in which worsening of kidney function is represented by increased plasma concentrations of uremic toxins (UTs), culminating in dialysis patients. As there is a high incidence of CVD in CKD patients, accompanied by arrhythmias and sudden cardiac death, knowledge on electrophysiological remodeling would be instrumental for understanding the CRS. While the interplay between both organs is clearly of importance in CRS, the involvement of UTs in pro-arrhythmic remodeling is only poorly investigated, especially regarding the mechanistic background. Currently, the clinical approach against potential arrhythmic events is mainly restricted to symptom treatment, stressing the need for fundamental research on UT in relation to electrophysiology. This review addresses the existing knowledge of UTs and cardiac electrophysiology, and the experimental research gap between fundamental research and clinical research of the CRS. Clinically, mainly absorbents like ibuprofen and AST-120 are studied, which show limited safe and efficient usability. Experimental research shows disturbances in cardiac electrical activation and conduction after inducing CKD or exposure to UTs, but are scarcely present or focus solely on already well-investigated UTs. Based on UTs data derived from CKD patient cohort studies, a clinically relevant overview of physiological and pathological UTs concentrations is created. Using this, future experimental research is stimulated to involve electrophysiologically translatable animals, such as rabbits, or in vitro engineered heart tissues.

Baroreceptor Sensitivity in Individuals with CKD and Heart Failure

Background

Heart failure is the most common cardiovascular complication of chronic kidney disease (CKD) and foreshadows a high morbidity and mortality rate. Baroreflex impairment likely contributes to cardiovascular mortality. We aimed to study the associations between CKD, heart failure, and baroreflex sensitivity (BRS) and their association with cardiovascular outcomes.

Methods

We retrospectively analyzed data from a cohort of 247 individuals with moderate to severe HF. All subjects underwent BRS measurements after intravenous phenylephrine along with electrocardiography, echocardiography, and laboratory measurements. We used logistic regression models to assess the association of CKD (estimated glomerular filtration rate <60 ml/min per 1.73 m²) with BRS using iterative models. Cox proportional hazards models were used to assess associations of binary BRS and subgroups according to categorizations of CKD and BRS with cardiovascular mortality.

Results

Median eGFR among individuals with CKD was 52 (IQR 44-56) ml/min per 1.73 m². eGFR was lower in those with depressed BRS (65 [IQR 54-76] ml/min per 1.73 m²) compared with those with preserved BRS (73 [IQR 64-87] ml/min per 1.73 m²; P≤0.001). The majority of individuals with CKD had depressed BRS compared with those without CKD (60% versus 29%; P=0.05). In regression models, CKD and BRS were independently associated. Cardiovascular mortality was significantly increased in individuals with or without CKD and depressed BRS compared with those with preserved BRS and CKD.

Conclusions

Cardiac BRS is depressed in patients with mild to moderate CKD and HF and associated with cardiovascular mortality. Additional study to confirm its contribution to cardiovascular mortality, particularly in advanced CKD, is warranted.

Early morning hemodynamic changes and left ventricular hypertrophy and mortality in hemodialysis patients

INTRODUCTION

An exaggeration of the early morning increase in BP, a phenomenon accompanied by a parallel rise in heart rate (HR), is a marker of high cardiovascular risk. The early morning changes in these parameters have not been investigated in the hemodialysis population.

METHODS

In a pilot, single center study including a series of 58 patients we measured the pre-awakening BP and HR surges and the nocturnal dipping of the same parameters as well as other established indicators of autonomic function (weighted 24 h systolic BP and HR variability) and tested their relationship with the left ventricular mass index (LVMI) and with the risk of death over a median follow up of 40 months.

RESULTS

The pre-awakening HR surge (r = - 0.46, P = 0.001) but not the corresponding BP surge (r = - 0.1, P = 0.98) was associated with LVMI and the risk of death [HR (1 unit): 0.89, 95% CI 0.83-0.96, P = 0.001]. The link between the pre-awakening HR surge with these outcome measures was robust and largely independent of established risk factors in the hemodialysis population, including the nocturnal dipping of BP. Weighted 24 h systolic BP and HR variability did not correlate with LVMI (all P > 0.11) nor with the risk of death (P > 0.11) and were also independent of the nocturnal dipping of systolic BP and HR.

CONCLUSION

This pilot study suggests that the low early morning changes in HR, likely reflecting enhanced sympathetic activity, entail a high risk for left ventricular hypertrophy (LVH) and mortality in the hemodialysis population.

Dynamic Echocardiographic Assessments Reveal Septal E/e' Ratio as Independent Predictor of Intradialytic Hypotension in Maintenance for Hemodialysis Patients with Preserved Ejection Fraction

BACKGROUND

Intradialytic hypotension (IDH) is a frequent and grave complication of hemodialysis (HD). However, the dynamic hemodynamic changes and cardiac performances during each dialytic session have been rarely explored in patients having IDH.

METHODS

Seventy-six HD patients (IDH = 40, controls = 36) were enrolled. Echocardiography examinations were performed in all patients at the pre-HD, during-HD and post-HD phases of a single HD session. A two-way analysis of variance was applied to compare differences of echocardiographic parameters between IDH and controls over time. The risk association was estimated by using a logistic regression analysis.

RESULTS

The IDH patients had a higher ejection fraction during HD followed by a greater reduction at the post-HD phase than the controls. Significant decreases in septal ratios of transmitral flow velocity to annular velocity (E/e') over times were detected between IDH patients and controls after adjusting for gender, age and ultrafiltration (p = 0.016). A lower septal E/e' ratio was independently associated with IDH (OR = 0.040; 95% CI = 0.003-0.606; p = 0.02). In contrast, significant systolic and diastolic dysfunctions over time were found in diabetic IDH compared to non-diabetic counterparts.

CONCLUSION

The septal E/e' ratio was a significant predictor for IDH.