The vicious cycle of dialysis-induced cardiac injury--are dynamic changes in diastolic function involved?

Update on Hemodialysis-Induced Multiorgan Ischemia: Brains and Beyond

Hemodialysis is a life-saving treatment for patients with kidney failure. However, patients requiring hemodialysis have a 10-20 times higher risk of cardiovascular morbidity and mortality than that of the general population. Patients encounter complications such as episodic intradialytic hypotension, abnormal perfusion to critical organs (heart, brain, liver, and kidney), and damage to vulnerable vascular beds. Recurrent conventional hemodialysis exposes patients to multiple episodes of circulatory stress, exacerbating and being aggravated by microvascular endothelial dysfunction. This promulgates progressive injury that leads to irreversible multiorgan injury and the well-documented higher incidence of cardiovascular disease and premature death. This review aims to examine the underlying pathophysiology of hemodialysis-related vascular injury and consider a range of therapeutic approaches to improving outcomes set within this evolved rubric.‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬.

Epidemiology of cardiovascular death in kidney failure: An Australian and New Zealand cohort study using data linkage

Aim

Cardiovascular mortality risk evolves over the lifespan of kidney failure (KF), as patients develop comorbid disease and transition between treatment modalities. Absolute cardiovascular death rates would help inform clinical practice and health‐care provision, but are not well understood across a continuum of dialysis and transplant states. We aimed to characterize cardiovascular death across the natural history of KF using a lifespan approach.

Methods

We performed a population‐based cohort study of incident patients commencing kidney replacement therapy in Australia and New Zealand. Cardiovascular deaths were identified using data linkage to national death registers. We estimated the probability of death and kidney transplant using multi‐state models, and calculated rates of graft failure and cardiovascular death across demographic factors and comorbidities.

Results

Among 60 823 incident patients followed over 381 874 person‐years, 25% (8492) of deaths were from cardiovascular disease. At 15 years from treatment initiation, patients had a 15.2% probability of cardiovascular death without being transplanted, but only 2.3% probability of cardiovascular death post‐transplant. Females had a 3% lower probability of cardiovascular death at 15 years (15.3% vs. 18.6%) but 4% higher probability of non‐cardiovascular death (54.5% vs. 50.8%). Within the first year of dialysis, cardiovascular mortality peaked in the second month and showed little improvement across treatment era.

Conclusion

Despite improvements over time, cardiovascular death remains common in KF, particularly among the dialysis population and in the first few months of treatment. Multi‐state models can provide absolute measures of cardiovascular mortality across both dialysis and transplant states.

In this population‐based cohort study using multi‐state models (alive without kidney transplant [KT], CV death without KT, non‐CV death without KT, alive after first KT, CV death after first KT and non‐CV death after first KT), the probability of CV death was higher in non‐KT than KT patients at 15 years from treatment. In patients on dialysis, CV mortality was highest from the second month after commencing dialysis and remained high thereafter. Thus, the use of multi‐state models provides helpful information on impacts of different treatments with respect to serious outcomes.

Preserved Cerebral Oxygenation with Worsening Global Myocardial Strain during Pediatric Chronic Hemodialysis

BACKGROUND

Cerebral and myocardial hypoperfusion occur during hemodialysis in adults. Pediatric patients receiving chronic hemodialysis have fewer cardiovascular risk factors, yet cardiovascular morbidity remains prominent.

METHODS

We conducted a prospective observational study of pediatric patients receiving chronic hemodialysis to investigate whether intermittent hemodialysis is associated with adverse end organ effects in the heart or with cerebral oxygenation (regional tissue oxyhemoglobin saturation [rSO2]). We assessed intradialytic cardiovascular function and rSO2 using noninvasive echocardiography to determine myocardial strain and continuous noninvasive near-infrared spectroscopy for rSO2. We measured changes in blood volume and measured central venous oxygen saturation (mCVO2) pre-, mid-, and post-hemodialysis.

RESULTS

The study included 15 patients (median age, 12 years; median hemodialysis vintage, 13.2 [9-24] months). Patients were asymptomatic. The rSO2 did not change during hemodialysis, whereas mCVO2 decreased significantly, from 73% to 64.8%. Global longitudinal strain of the myocardium worsened significantly by mid-hemodialysis and persisted post-hemodialysis. The ejection fraction remained normal. Lower systolic BP and faster blood volume change were associated with worsening myocardial strain; only blood volume change was significant in multivariate analysis (β-coefficient, -0.3; 95% confidence interval [CI], -0.38 to -0.21; P<0.001). Blood volume change was also associated with a significant decrease in mCVO2 (β-coefficient, 0.42; 95% CI, 0.07 to 0.76; P=0.001). Access, age, hemodialysis vintage, and ultrafiltration volume were not associated with worsening strain.

CONCLUSIONS

Unchanged rSO2 suggested that cerebral oxygenation was maintained during hemodialysis. However, despite maintained ejection fraction, intradialytic myocardial strain worsened in pediatric hemodialysis and was associated with blood volume change. The effect of hemodialysis on individual organ perfusion in pediatric versus adult patients receiving hemodialysis might differ.

Coronary artery disease in dialysis patients: evidence synthesis, controversies and proposed management strategies

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality among patients with end-stage renal disease (ESRD). Clustering of traditional atherosclerotic and non-traditional risk factors drive the excess rates of coronary and non-coronary CVD in this population. The incidence, severity and mortality of coronary artery disease (CAD) as well as the number of complications of its therapy is higher in dialysis patients than in non-chronic kidney disease patients. Given the lack of randomized clinical trial evidence in this population, current practice is informed by observational data with a significant potential for bias. Furthermore, guidelines lack any recommendation for these patients or extrapolate them from trials performed in non-dialysis patients. Patients with ESRD are more likely to be asymptomatic, posing a challenge to the correct identification of CAD, which is essential for appropriate risk stratification and management. This may lead to "therapeutic nihilism", which has been associated with worse outcomes. Here, the ERA-EDTA EUDIAL Working Group reviews the diagnostic work-up and therapy of chronic coronary syndromes, unstable angina/non-ST elevation and ST-elevation myocardial infarction in dialysis patients, outlining unclear issues and controversies, discussing recent evidence, and proposing management strategies. Indications of antiplatelet and anticoagulant therapies, percutaneous coronary intervention and coronary artery bypass grafting are discussed. The issue of the interaction between dialysis session and myocardial damage is also addressed.

Changes of cardiac functions after hemodialysis session in pediatric patients with end-stage renal disease: conventional echocardiography and two-dimensional speckle tracking study

BACKGROUND

Although acute effects of hemodialysis (HD) on cardiac functions in end-stage renal disease (ESRD) have been studied frequently in adults, limited data are available in pediatric age. Therefore, this work elucidates the acute impact of HD on cardiac functions using conventional echocardiography and two-dimensional (2D) speckle tracking in ESRD pediatric patients.

METHODS

Between June 2018 and April 2019, 40 ESRD pediatric subjects on chronic HD were prospectively recruited. All patients were subjected to history taking and baseline laboratory tests. Anthropometric measures, heart rate, blood pressure, and bioimpedance were assessed before and after HD session. Moreover, conventional echocardiography including M.mode and Doppler parameters for valves, as well as left ventricle (LV) 2D speckle tracking were performed pre- and post-dialysis session.

RESULTS

The included patients mean age was 12.9 ± 2.9 years, and males were 24 (60%). Significant reductions in body weight and blood pressure were noted after sessions. Post-dialysis LV and left atrial diameters, as well as left atrium to aortic diameter ratio, were lower. Nevertheless, conventional echocardiography-derived LV ejection fraction (EF), and fractional shortening were not significantly changed. Doppler-derived E/A ratio of mitral and tricuspid valves were lower post-dialysis. Global longitudinal strain (GLS) for LV was significantly reduced after dialysis (- 20.31 ± 3.58%, - 17.17 ± 3.40% vs, P < 0.0001), and global circumferential strain (GCS) was lower post-dialysis in comparison to pre-dialysis (- 21.37 ± 6.46% vs - 17.74 ± 6.16%, P < 0.0001). The speckle tracking-derived EF was significantly lower post-dialysis (57.58 ± 6.94 vs 53.64 ± 10.72, P = 0.018). All myocardial segments longitudinal and circumferential strains decreased significantly after dialysis.

CONCLUSIONS

Post-hemodialysis significant decline in left ventricular EF as well as global and segmental strains can be detected in ESRD pediatric patients using 2D speckle tracking, despite the nonsignificant changes in systolic functions derived from conventional echocardiography. This is considered additional evidence of HD deleterious effect on myocardial functions, particularly in the pediatric age.

Acute stunning effect of hemodialysis on myocardial performance: A three-dimensional speckle tracking echocardiographic study

The effects of acute changes during hemodialysis (HD) on the myocardium are not yet known. The invention of three-dimensional speckle tracking echocardiography (3DSTE) has offered clinicians a new method to assess the movements of ventricular segments simultaneously in three spatial directions. The aim of this study was to evaluate the effect of first weekly standard HD process on the left ventricle (LV) and right ventricle (RV) global and regional myocardial function in patients with normal left ventricle ejection fraction using 3DSTE-derived indices. Patients (n=38) receiving maintenance HD in our clinic who have no known cardiovascular disease are examined just before and after a HD session using 3DSTE. Demographic and comorbidity data, renal replacement treatment characteristics, and laboratory test results are recorded. 3DSTE analysis is performed to calculate the LV global longitudinal, circumferential area and radial peak systolic strain, as well as RV septum and free-wall longitudinal strain and fractional area change. Patients are aged 52.8 ± 13.6 years and 52.6% of them are male. Mean dialysis duration is 56 months. The LV strain values of the patients changed markedly before and after HD (GLS: -14.2 ± 5.2, -11.1 ± 4.6 [P < .001], GCS: -14.8 ± 4.2, -12.4 ± 5.28 [P < .009]; GRS: 41.5 ± 16, 33.3 ± 16.5 [P = .003]; AREA -24.7 ± 7.2, -20.1 ± 7.6 [P = .001], respectively). We could not demonstrate any improvement in RV strain values before or after HD. LV strain values are positively correlated with blood pressure variability during the dialysis sessions. LV function is preserved better after HD in patients on beta or calcium channel blocker therapy compared to those who do not use these agents (P < .001, P < .01, respectively). HD treatment results in deterioration in all LV strain directions but not in RV. Strain assessment may improve vascular risk stratification of patients on chronic HD.

The Ebb and Flow of Echocardiographic Cardiac Function Parameters in Relationship to Hemodialysis Treatment in Patients with ESRD

Cardiovascular disease is the leading cause of mortality in patients receiving hemodialysis. Cardiovascular events in these patients demonstrate a day-of-week pattern; i.e., they occur more commonly during the last day of the long interdialytic interval and the first session of the week. The hemodialysis process causes acute decreases in cardiac chamber size and pulmonary circulation loading and acute diastolic dysfunction, possibly through myocardial stunning and other non-myocardial-related mechanisms; systolic function, in contrast, is largely unchanged. During interdialytic intervals volume overload, acid-base, and electrolyte shifts, as well as arterial and myocardial wall changes, result in dilatation of right cardiac chambers and pulmonary circulation overload. Recent studies suggest that these alterations are more extended during the long interdialytic interval or the first dialysis session of the week and are associated with excess volume overload or removal, respectively, thus adding a mechanism for the day-of-week pattern of mortality in patients receiving hemodialysis. This review summarizes the existing data from echocardiographic studies of cardiac morphology and function during the hemodialysis session, as well as during the interdialytic intervals.

Haemodialysis acutely deteriorates left and right diastolic function and myocardial performance: an effect related to high ultrafiltration volumes?

Background

The effect of acute preload reduction during haemodialysis on left ventricle (LV) and right ventricle (RV) function is not well understood. This study aimed to evaluate acute changes in novel echocardiographic and tissue Doppler-derived indices of LV and RV function during the first and a standard weekly dialysis session and to examine the possible effect of acute intradialytic volume changes in LV and RV diastolic function and pulmonary circulation loading.

Methods

Forty-one adult patients receiving standard thrice-weekly haemodialysis participated in this study. Two-dimensional echocardiographic and tissue Doppler imaging (TDI) studies were performed with a standard cardiac ultrasound device (Vivid 7 or Vivid e, GE, Horton, Norway) shortly before and after the first weekly and a standard dialysis session. Multiple linear regression analysis was applied to assess the effect of volume changes on peak early mitral (E) and tricuspid (E RV) velocities changes.

Results

Significant reductions from pre- to post-haemodialysis were noted in body weight and systolic blood pressure. Post-haemodialysis left and right atrial, LV and RV sizing echocardiographic parameters were lower. LV systolic function, represented by LV ejection fraction, cardiac output and mean peak systolic LV and RV velocities at the annulus level, was unchanged. Diastolic function indices such as E (first session: 0.96 ± 0.28 versus 0.75 ± 0.27 m/s, P < 0.001; standard session: 0.89 ± 0.24 versus 0.78 ± 0.29, P < 0.001) and E RV (first session: 0.89 ± 0.26 versus 0.67 ± 0.25 m/s, P < 0.001; standard session: 0.86 ± 0.24 versus 0.77 ± 0.31, P < 0.001), E/A LV ratio, TDI peak early mitral (E') velocity and E'/A' RV ratio were reduced after haemodialysis. Pulmonary circulation loading, represented by RV systolic pressure, was significantly improved. In multiple regression model analysis, intradialytic weight loss was independently associated with changes in E [β = 0.042 (95% CI 0.018-0.066)] and E RV [β = 0.084 (95% CI 0.057-0.110)].

Conclusions

This study shows that haemodialysis deteriorates cardiac diastolic function indices and improves pulmonary circulation loading, while systolic function remains unchanged. High intradialytic volume removal may affect cardiac diastolic function.

High cardiovascular event rates occur within the first weeks of starting hemodialysis

Early mortality is high in hemodialysis (HD) patients, but little is known about early cardiovascular event (CVE) rates after HD initiation. To study this we analyzed data in the AROii cohort of incident HD patients from over 300 European Fresenius Medical Care dialysis centers. Weekly rates of a composite of CVEs during the first year and monthly rates of the composite and its constituents (coronary artery, cerebrovascular, peripheral arterial, congestive heart failure, and sudden cardiac death) during the first 2 years after HD initiation were assessed. Of 6308 patients that started dialysis within 7 days, 1449 patients experienced 2405 CVEs over the next 2 years. The first-year CVE rate (30.2/100 person-years; 95% CI, 28.7-31.7) greatly exceeded the second-year rate (19.4/100; 95% CI, 18.1-20.8). Composite CVEs were highest during the first week with increased risk compared with the second year, persisting until the fifth month. Except for sudden cardiac death, temporal patterns of rates for all CVE categories were very similar, with highest rates during the first month and a high-risk period extending to 4 months. Higher or lower cumulative weekly dialysis dose, lower blood flow, and lower net ultrafiltration during dialysis were associated with CVE during the high-risk period, but not during the post high-risk period. Thus, the incidence of CVE in the first weeks after HD initiation is much higher than during subsequent periods which raises concerns that HD initiation may trigger CVEs.