The role of echocardiographic study in patients with chronic kidney disease

Oxygen venous saturation is associated with subclinical myocardial systolic dysfunction in patients with end-stage renal disease undergoing hemodialysis

Introduction

The aim of this prospective study was to evaluate the impact of hemodialysis (HD) on myocardial injury, of both right and left ventricle function as well as their association with venous oxygen saturation (ScvO2) alterations.

Material and methods

We included in the study stable consecutive patients with end-stage renal disease (ESRD) undergoing regular HD. Right and left ventricular speckle-tracking echocardiographies were performed in all patients. The examination calculates the global systolic longitudinal strain (GLS). Blood samples were obtained from the central vein in order to measure the O2 saturation (ScvO2) levels prior and post HD. High sensitive troponin (HST) was also measured in all patients before and after HD.

Results

Thirty seven patients were evaluated. We found that both mean ScvO2 and left ventricle GLS (LV GLS) were deteriorated after the dialysis session: 76.47 ±1.98 to 71.54 ±5.10, p < 0.05 and -17.73 ±3.44 to -14.21 ±3.44%, p < 0.01, respectively. HST levels were increased at the end of hemodialysis, 22.45 ±13.26 to 106.78 ±146.19 pg/ml, p < 0.01. A significant correlation was also found between the decrease of LV GLS with the ScvO2 reduction, p = 0.001, as well as with the increase of the HST levels, p = 0.001.

Conclusions

Our data demonstrate that there is a significant worsening of the GLS of the left ventricle at the end of the dialysis, which is strongly associated with the concomitant deterioration of ScvO2. The may be a reliable index of circulatory stress indicating a subclinical myocardial dysfunction during HD.

Pathophysiological concepts and screening of cardiovascular disease in dialysis patients

Dialysis patients experience 10-20 times higher cardiovascular mortality than the general population. The high burden of both conventional and nontraditional risk factors attributable to loss of renal function can explain higher rates of cardiovascular disease (CVD) morbidity and death among dialysis patients. As renal function declines, uremic toxins accumulate in the blood and disrupt cell function, causing cardiovascular damage. Hemodialysis patients have many cardiovascular complications, including sudden cardiac death. Peritoneal dialysis puts dialysis patients with end-stage renal disease at increased risk of CVD complications and emergency hospitalization. The current standard of care in this population is based on observational data, which has a high potential for bias due to the paucity of dedicated randomized clinical trials. Furthermore, guidelines lack specific guidelines for these patients, often inferring them from non-dialysis patient trials. A crucial step in the prevention and treatment of CVD would be to gain better knowledge of the influence of these predisposing risk factors. This review highlights the current evidence regarding the influence of advanced chronic disease on the cardiovascular system in patients undergoing renal dialysis.

Echocardiographic parameters in patients with and without hypotension during dialysis

Introduction: Hypotension during dialysis is a common complication of hemodialysis and is associated with increased patient mortality and morbidity. Intradialytic hypotension is a decrease in systolic BP ≥20 mm Hg or a reduction in mean arterial pressure by 10 mm Hg along with clinical events and the need for correction. This study compares cardiac function, using transthoracic echocardiography with strain modality in patients with intradialytic hypotension with those without hypotension during dialysis.

Methods: We studied 60 patients with chronic renal failure undergoing regular hemodialysis from April 2018 to February 2019. We compared thirty patients in the intradialytic hypotension group, with the remaining 30 patients in the control group. We did transthoracic echocardiography a day after hemodialysis using conventional, tissue doppler, and strain imaging.

Results: Early diastolic mitral annulus velocity (e’) was lower in the intradialytic hypotension group in comparison with the control group which their difference was statistically significant (5.540 ± 1.51 versus 6.920 ± 1.98, P value:0.007) Left Ventricular Ejection Fraction (LVEF) was also significantly lower in the intradialytic hypotension group (51.07 ± 8.714 versus 59.43 ± 4.133, P value < 0.001). Global Longitudinal Strain (GLS) was significantly lower in the intradialytic hypotension group (-14.17 ± 2.79 versus -18.99 ± 2.25, P value < 0.001). The receiver operator characteristics (ROC) curve point-coordinates that GLS of -16.85 and lower (more positive) has 83% sensitivity and 87% specificity for intradialytic hypotension.

Conclusion: The echocardiographic assessment could be used as a tool for the prediction of hypotension during dialysis.

Unilateral Ureteral Obstruction for 28 Days in Rats Is Not Associated with Changes in Cardiac Function or Alterations in Mitochondrial Function

Our work evaluated cardiac function and mitochondrial bioenergetics parameters in hearts from male Wistar rats subjected to the UUO model during 28 days of progression. We measured markers of kidney damage and inflammation in plasma and renal fibrosis by histological analysis and Western blot. Cardiac function was evaluated by echocardiography and proteins involved in cardiac damage by Western blot. Oxygen consumption and transmembrane potential were monitored in cardiac mitochondria using high-resolution respirometry. We also determined the activity of ATP synthase and antioxidant enzymes such as glutathione peroxidase, glutathione reductase, and catalase. Our results show that, although renal dysfunction is established in animals subjected to ureteral obstruction, cardiac function is maintained along with mitochondrial function and antioxidant enzymes activity after 28 days of injury evolution. Our results suggest that renocardiac syndrome might develop but belatedly in obstruction-induced renal damage, opening the opportunity for treatment to prevent this condition.

Right Ventricular Functionality Following Hemodialysis Initiation in End-Stage Kidney Disease-A Single-Center, Prospective, Cohort Study

Background and Objectives: Two-dimensional speckle tracking echocardiography (2D-STE) is viewed as an outstanding technique, competent of uncovering earlier subclinical myocardial anomalies compared to conventional echocardiography. A few endeavors adopted 2D-STE as a tool to estimate right ventricular (RV) function in subjects with end-stage kidney disease (ESKD). There is no published prospective study on an adult ESKD cohort exploring the consequences of commencing elective hemodialysis (HD) on RV behavior. Materials and Methods: We investigated the RV systolic function using traditional (tricuspid annular plane systolic excursion-TAPSE, RV fractional area change-FAC) and 2D-STE (RV free wall longitudinal strain-RVFWLS) parameters following the initiation of HD. We enrolled 79 consecutive patients with ESKD and assessed them in four steps-at baseline, before HD, and at 3, 6, and 12 months. Results: RVFWLS, FAC, and TAPSE values had a significant increase at 3, 6, and 12 months from baseline (p < 0.001) and a significant increase at 6 months from 3 months (p < 0.001). However, differences between 12 months and 6 months were not significant (p > 0.05) according to Dunn-Bonferroni post hoc tests. Seventeen deaths were recorded before the completion of the study. RVFWLS, FAC, and TAPSE values significantly decreased at 3 and 6 months in all 17 deceased patients, in clear opposition with the values survivors had. All the studied parameters had a significant prediction power on mortality (p < 0.001) having an outstanding performance: baseline-RVFWLS (AUC: 1.000 (95% C.I.: 1.000-1.000)), baseline-FAC (AUC: 0.974 (95% C.I.: 0.942-1.000)), and baseline-TAPSE (AUC: 0.962 (95% C.I.: 0.920-1.000). Conclusions: Our study is the first to investigate RV function by 2D-STE and correlate it with traditional methods in patients with ESKD before and after the initiation of HD. RV function was significantly ameliorated at 3, 6, and 12 months compared to the pre-HD values. FAC and RVFWLS gain an outstanding prognostic role on mortality in this population.

Ratio of Early Mitral Inflow Velocity to the Global Diastolic Strain Rate and Global Left Ventricular Longitudinal Systolic Strain Predict Overall Mortality and Major Adverse Cardiovascular Events in Hemodialysis Patients

Background

The ratio of early mitral inflow velocity to the global diastolic strain rate (E/E'sr) and global longitudinal systolic strain (GLS) of the left ventricle (LV) are emerging indices of diastolic and systolic functions, respectively, for the LV. Their prognostic significance in the prediction of mortality and cardiovascular (CV) outcomes remains underexplored in hemodialysis (HD) patients.

Methods

This prospective study included 190 maintenance HD patients. The E/E'sr ratio and GLS were assessed using two-dimensional speckle tracking echocardiography. The clinical outcomes included overall mortality, CV mortality, and major adverse cardiovascular events (MACE). The associations between the E/E'sr ratio, GLS, and clinical outcomes were evaluated using multivariate Cox regression analysis. The incremental values of the E/E'sr ratio and GLS in outcome prediction were assessed by χ ² changes in Cox models.

Results

Over a median follow-up period of 3.7 years, there were 35 overall deaths, 16 CV deaths, and 45 MACE. Impaired diastolic function with a higher E/E'sr ratio was associated with overall mortality (HR, 1.484; 95% CI, 1.201-1.834; p < 0.001), CV mortality (HR, 1.584; 95% CI, 1.058-2.371; p = 0.025), and MACE (HR, 1.205; 95% CI, 1.040-1.397; p = 0.013) in multivariate adjusted Cox analysis. Worsening GLS was associated with overall mortality (HR, 1.276; 95% CI, 1.101-1.480; p = 0.001), CV mortality (HR, 1.513; 95% CI, 1.088-2.104; p = 0.014), and MACE (HR, 1.214; 95% CI, 1.103-1.337; p < 0.001). The E/E'sr ratio and GLS had better outcome prediction than the E to early diastolic mitral annular velocity (E/E') ratio and left ventricular ejection fraction (LVEF). Moreover, adding the E/E'sr ratio and GLS to Cox models containing relevant clinical and conventional echocardiographic parameters improved the prediction of overall mortality (p < 0.001), CV mortality (p < 0.001), and MACE (p < 0.001).

Conclusion

The E/E'sr ratio and GLS, as emerging indices of LV diastolic and systolic functions, significantly predict mortality and CV outcomes and outperform conventional echocardiographic parameters in outcome prediction in HD patients.

Age- and Body Size-Adjusted Left Ventricular End-Diastolic Dimension in a Japanese Hospital-Based Population

BACKGROUND

Using the normal values for the East Asian population, we evaluated age- and body size-adjusted left ventricular end-diastolic dimension (LVEDD) and its prognostic impact in a hospital-based population in Japan. Methods and Results: We retrospectively analyzed data obtained from 4,444 consecutive patients who had undergone both transthoracic echocardiography and electrocardiography at Kitano Hospital in 2013. Those who presented with a history of previous episodes of myocardial infarction and severe or moderate valvular disease or with low ejection fraction (<50%) were excluded from the analysis. We calculated LVEDD adjusted by age and body surface area. A total of 3,474 patients were categorized into 3 groups: 401 with large adjusted LVEDD, 2,829 with normal adjusted LVEDD, and 244 with small adjusted LVEDD. Mean patient age in the large, normal, and small adjusted LVEDD groups was 66.6±18.4, 65.6±15.7, and 62.1±15.5 years, respectively (P<0.001). After adjusting for confounding factors, the excess adjusted 3-year risk of primary outcome of large adjusted LVEDD relative to normal LVEDD was significant (HR, 1.40; 95% CI: 1.08-1.78). The risk for primary outcomes of small adjusted LVEDD relative to normal adjusted LVEDD was significantly lower (HR, 0.55; 95% CI: 0.34-0.85).

CONCLUSIONS

Adjusted large LVEDD has a deleterious impact on long-term mortality, whereas small LVEDD carried a significantly lower risk.

Changes of Left and Right Ventricle Mechanics and Function in Patients with End-Stage Renal Disease Undergoing Haemodialysis

Background and objectives: Chronic kidney disease (CKD) increases the risk of cardiovascular diseases even in its early stages and is associated with structural and functional cardiac abnormalities. The aim of this study was to use speckle-tracking echocardiography (STE) to evaluate left and right ventricle mechanics and function, markers of subclinical dysfunction in patients with end-stage renal disease (ESRD) undergoing haemodialysis. Methods: Patients with ESRD undergoing regular haemodialysis and with preserved left ventricle (LV) ejection fraction (EF) (n = 38) were enrolled in this retrospective study. The control group consisted of 32 age-matched persons with normal kidney function (glomerular filtration rate (GFR) >90 mL/min/1.73 m² according to Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)). Conventional 2D echocardiography and STE were performed in all patients. Results: 70 individuals, 31 (44.29%) males and 39 (55.71%) females, were included in the study. There were no significant differences in age, sex and body surface area between the groups. LV end diastolic diameter did not differ between the groups, while LV myocardial mass index was higher in the group of patients on haemodialysis (111.64 ± 27.99 versus 84.21 ± 16.99, p < 0.001) and LV diastolic dysfunction (LVDD) was found in 31 (81.6%) patients of this group. LV global longitudinal strain (GLS) (-22.43 ± 2.71 versus -24.73 ± 2.03, p < 0.001) and LV global circumferential strain (GCS) at the mitral valve and papillary muscles levels (-18.73 ± 3.49 versus -21.67 ± 2.22, p < 0.001; -18.64 ± 2.75 versus -20.42 ± 2.38, p = 0.005, respectively) were significantly lower in haemodialysis group patients. The parameters of the right ventricle (RV) free wall longitudinal function including RV GLS (-22.63 ± 3.04 versus -25.45 ± 2.48, p < 0.001), were reduced in haemodialysis patients compared with the controls. However, RV fractional area change (FAC) did not differ between the groups (p = 0.19). Conclusion: Patients with ESRD and preserved LV ejection fraction undergoing haemodialysis had a higher prevalence of LVDD and impaired LV longitudinal and circumferential deformation indices, as well as reduced RV longitudinal function and deformation parameters compared with the age-matched healthy controls. STE helps to detect subclinical LV and RV dysfunction in chronic haemodialysis patients.

Pathological cardiac remodeling occurs early in CKD mice from unilateral urinary obstruction, and is attenuated by Enalapril

Cardiovascular disease constitutes the leading cause of mortality in patients with chronic kidney disease (CKD) and end-stage renal disease. Despite increasing recognition of a close interplay between kidney dysfunction and cardiovascular disease, termed cardiorenal syndrome (CRS), the underlying mechanisms of CRS remain poorly understood. Here we report the development of pathological cardiac hypertrophy and fibrosis in early stage non-uremic CKD. Moderate kidney failure was induced three weeks after unilateral urinary obstruction (UUO) in mice. We observed pathological cardiac hypertrophy and increased fibrosis in UUO-induced CKD (UUO/CKD) animals. Further analysis indicated that this cardiac fibrosis was associated with increased expression of transforming growth factor β (TGF-β) along with significant upregulation of Smad 2/3 signaling in the heart. Moreover early treatment of UUO/CKD animals with an angiotensin-converting-enzyme inhibitor (ACE I), Enalapril, significantly attenuated cardiac fibrosis. Enalapril antagonized activation of the TGF-β signaling pathway in the UUO/CKD heart. In summary our study demonstrates the presence of pathological cardiac hypertrophy and fibrosis in mice early in UUO-induced CKD, in association with early activation of the TGF-β/Smad signaling pathway. We also demonstrate the beneficial effect of ACE I in alleviating this early fibrogenic process in the heart in UUO/CKD animals.

Short-term heart rate variability as a predictor of long-term survival in patients with chronic hemodialysis: A prospective cohort study

BACKGROUND

Heart rate variability (HRV), a non-invasive measurement of the sympathetic-vagal balance, has been demonstrated as a predictor of long-term survival in various patient populations. However, its predictive value in patients with end-stage renal disease (ESRD) has not been evaluated in a long-term follow-up study.

METHODS

Prospective data collected for 41 patients with chronic hemodialysis (age 59 ± 10 years, men 51.3%, diabetes mellitus 31%, and duration of dialysis 64 ± 50 months) who underwent a 5-minute electrocardiogram (ECG) recording as a baseline for frequency domain HRV analysis.

RESULTS

During a median follow-up of 150.2 months from 2003 to 2014, 15 (35.7%) patients died (3 due to cardiac causes and 12 due to non-cardiac causes). The Cox proportional hazards model suggested that the low frequency versus high frequency signal (LF/HF) of a high ratio for the HRV and diabetes mellitus were two independent predictors of mortality (hazard ratios 3.028 and 3.494; p = 0.033 and 0.022, respectively). Less reduction in MAP during dialysis showed borderline significance of long-term survival than those with larger drop (p = 0.058).

CONCLUSION

A short ECG recording and an analysis of the frequency domain of the HRV is clinically predictive of the long-term survival of patients with chronic hemodialysis.