Acute effects of hemodialysis on left ventricular function evaluated by tissue Doppler imaging

Major Outcomes With Personalized Dialysate TEMPerature (MyTEMP): Rationale and Design of a Pragmatic, Registry-Based, Cluster Randomized Controlled Trial

BACKGROUND

Small randomized trials demonstrated that a lower compared with higher dialysate temperature reduced the average drop in intradialytic blood pressure. Some observational studies demonstrated that a lower compared with higher dialysate temperature was associated with a lower risk of all-cause mortality and cardiovascular mortality. There is now the need for a large randomized trial that compares the effect of a low vs high dialysate temperature on major cardiovascular outcomes.

OBJECTIVE

The purpose of this study is to test the effect of outpatient hemodialysis centers randomized to (1) a personalized temperature-reduced dialysate protocol or (2) a standard-temperature dialysate protocol for 4 years on cardiovascular-related death and hospitalizations.

DESIGN

The design of the study is a pragmatic, registry-based, open-label, cluster randomized controlled trial.

SETTING

Hemodialysis centers in Ontario, Canada, were randomized on February 1, 2017, for a trial start date of April 3, 2017, and end date of March 31, 2021.

PARTICIPANTS

In total, 84 hemodialysis centers will care for approximately 15 500 patients and provide over 4 million dialysis sessions over a 4-year follow-up.

INTERVENTION

Hemodialysis centers were randomized (1:1) to provide (1) a personalized temperature-reduced dialysate protocol or (2) a standard-temperature dialysate protocol of 36.5°C. For the personalized protocol, nurses set the dialysate temperature between 0.5°C and 0.9°C below the patient's predialysis body temperature for each dialysis session, to a minimum dialysate temperature of 35.5°C.

PRIMARY OUTCOME

A composite of cardiovascular-related death or major cardiovascular-related hospitalization (a hospital admission with myocardial infarction, congestive heart failure, or ischemic stroke) captured in Ontario health care administrative databases.

PLANNED PRIMARY ANALYSIS

The primary analysis will follow an intent-to-treat approach. The hazard ratio of time-to-first event will be estimated from a Cox model. Within-center correlation will be considered using a robust sandwich estimator. Observation time will be censored on the trial end date or when patients die from a noncardiovascular event.

TRIAL REGISTRATION

www.clinicaltrials.gov; identifier: NCT02628366.

Acute Haemodialysis-induced Changes in Tissue Doppler Echocardiography Parameters

BACKGROUND

Tissue Doppler imaging (TDI) is a method that determines the tissue motion and velocity within the myocardium.

AIMS

To characterize acute haemodialysis (HD)-induced changes in TDI-derived indices for patients that have end-stage renal disease (ESRD).

STUDY DESIGN

Cross sectional study.

METHODS

Conventional echocardiography and TDI methods were applied to study ESRD patients (n=58) before and after HD. Pulmonary venous flow, mitral inflow, and TDI signals of the lateral and septal mitral annulus were examined for the determination of altered left-ventricular diastolic filling parameters. Flow velocities from early- (E) and late-atrial (A) peak transmitral; peak pulmonary vein systolic (S) and diastolic (D); and myocardial peak systolic (Sm) and peak early (Em) and late (Am) diastolic mitral annular velocities were also assessed for changes.

RESULTS

Transmitral E and A velocities and the E/A ratio decreased significantly after HD (p<0.001). Pulmonary vein S (p<0.001) and D (p<0.001) velocities decreased, and S/D ratios increased significantly (p=0.027). HD led to a reduction in septal Em (p<0.001), lateral Em (p=0.006), and Am (p<0.001) velocities. Contrary to the decreases in Em and Am, the Em/Am ratio remained unchanged.

CONCLUSION

A single HD session was associated with an acute deterioration in the diastolic parameters. Since the Em/Am ratio remained unchanged, we conclude that this index is a relatively load-independent measure of diastolic function in HD patients.

What Is the Meaning of Increased Myocardial Injury Enzymes during Hemodialysis? A Tissue Doppler Imaging Study

BACKGROUND

Cardiovascular death is decreasing in the general population; however, it appears in still higher rates and even increases gradually in hemodialysis (HD) patients. This situation has led to a debate about cardiovascular adverse effects of HD which lead to significant changes in cardiac and hemodynamic events. It is known that troponins are often elevated in HD patients, and high levels of troponin are associated with increased mortality. Therefore, it is difficult to interpret the value of elevations in chronic kidney disease patients.

METHODS

Echocardiographic and biochemical parameters of 41 patients treated with HD were evaluated before and after a HD session.

RESULTS

HD led to an increased heart rate, and tissue Doppler imaging parameters such as early diastolic mitral peak velocity (E)/early diastolic myocardial peak velocity (é) and septal é decreased significantly after HD. HD caused an increase in troponin I, myoglobin and cardiac creatine kinase (CK MB) levels (p = 0.019, p < 0.001 and p = 0.018, respectively). A decrease in the left ventricular peak systolic myocardial (LV S') velocity (p = 0.011) was detected in patients with increased levels of cardiac damage markers (group 2) compared to those without increased levels of cardiac damage markers (group 1) in HD.

CONCLUSION

A decrease in LV S' velocity was found to be an independent predictor of an increase of myocardial injury enzymes in HD (odds ratio = 1.099; p = 0.039). We concluded that HD may lead to significant acute stress upon the myocardium.

Assessment of left ventricular hemodynamics and function of patients with uremia by vortex formation using vector flow mapping

A novel echocardiographic method, vector flow mapping (VFM), acquires velocity vector from color Doppler velocity data. The purpose of this study was to evaluate whether VFM could provide useful information on intracardiac flow and helpful to evaluate left ventricular (LV) function. Thirty-eight patients with uremia undergoing hemodialysis and 30 healthy volunteers were enrolled. The maximum vector velocity, maximum diameter and duration of the intracardiac vortex were measured using VFM software during systole and diastole. The maximum vector velocity of the vortex and the peak velocities at the basal septum and lateral mitral annulus measured by tissue Doppler imaging (TDI) were correlated. The maximum diameter and duration of vortex formation were significantly higher in uremic patients compared with the control group during the ejection phase (40.6 ± 7.9 cm/sec vs. 28.1 ± 3.9 cm/sec; 297.1 ± 22.1 msec vs. 145.4 ± 19.3 msec, all P < 0.001). The maximal diameters of the vortex were higher in uremic patients compared with the control group during diastole (25.6 ± 3.4 mm vs. 16.4 ± 2.1 mm; 34.3 ± 3.1 mm vs. 26.8 ± 3.9 mm; 37.5 ± 2.4 mm vs. 20.9 ± 2.1 mm; all P < 0.001). The maximum vector velocities were lower in mid-diastole and late diastole (23.6 ± 2.3 cm/sec vs. 45.2 ± 3.7 cm/sec; 31.9 ± 2.9 cm/sec vs. 54.7 ± 3.2 cm/sec, all P < 0.001). There was a correlation between the maximum vector velocity of the vortex in mid-diastole and E'/A' at the septum and lateral mitral annulus (r = 0.70, r = 0.76, P < 0.001). Vortex can be utilized to provide intracardiac dynamic information using VFM and it may be a good supplement for evaluating LV function.

Perioperative assessment of diastolic dysfunction

Assessment of diastolic function should be a component of a comprehensive perioperative transesophageal echocardiographic examination. Abnormal diastolic function exists in >50% of patients presenting for cardiac and high-risk noncardiac surgery, and has been shown to be an independent predictor of adverse postoperative outcome. Normalcy of systolic function in 50% of patients with congestive heart failure implicates diastolic dysfunction as the probable etiology. Comprehensive evaluation of diastolic function requires the use of various, load-dependent Doppler techniques This is further complicated by the additional effects of dehydration and anesthetic drugs on myocardial relaxation and compliance as assessed by these Doppler measures. The availability of more sophisticated Doppler techniques, e.g., Doppler tissue imaging and flow propagation velocity, makes it possible to interrogate left ventricular diastolic function with greater precision, analyze specific stages of diastole, and to differentiate abnormalities of relaxation from compliance. Additionally, various Doppler-derived ratios can be used to estimate left ventricular filling pressures. The varying hemodynamic environment of the operating room mandates modification of the diagnostic algorithms used for ambulatory cardiac patients when left ventricular diastolic function is evaluated with transesophageal echocardiography in anesthetized surgical patients.

Hemodialysis does not impair ventricular functions over 2 years

We aimed to evaluate the long-term effect of hemodialysis (HD) treatment on left and right ventricular (LV and RV) functions in patients with end-stage renal disease. The study population consisted of 22 patients with newly diagnosed end-stage renal disease. Before an arteriovenous fistula was surgically created for HD, the patients were evaluated by echocardiography for systolic and diastolic functions. After the first HD session (mean 24.22 ± 2.14 months), the second echocardiographic evaluations were performed. Left ventricular and RV functions before and after long-term HD treatment were compared. The mean age was 55 ± 13 years and 10 (45%) of the patients were female. After long-term HD treatment, the isovolumic relaxation time was significantly decreased; however, the peak early (E) and late (A) diastolic mitral inflow velocities, E/A ratio, and deceleration time of E wave were not significantly different from the baseline measurements. Also, there was no significantly change in the early diastolic velocity (Ea) of the lateral mitral anulus and the E/Ea ratio. Pulmonary vein peak diastolic velocity, peak atrial reversal velocity, and peak atrial reversal velocity duration remained almost unchanged even though the pulmonary vein peak systolic velocity and the pulmonary vein peak systolic velocity/pulmonary vein peak diastolic velocity ratio were significantly lower after long-term HD treatment. In addition, LV systolic functions, LV diameters, LV mass index, left atrium size, and RV diastolic functions were not statistically different after long-term HD treatment. The myocardium is exposed to hemodynamic, metabolic, and neuro-humoral abnormalities during HD treatment; however, the long-term effects of HD on ventricular functions are not clearly known. The present study showed that the long-term effects of HD on LV and RV functions were insignificant in patients with end-stage renal disease. We have demonstrated that the LV and RV functions did not change significantly after long-term HD treatment. We suggest that this result may be due to regulated blood pressure levels of the patients, treatment of anemia and other metabolic disorders during the HD period and the prevention of weight gain and hypervolemia.

[Effects of acute decrease in preload on echocardiographic indices of systolic and diastolic function of the left ventricle in children with end-stage renal disease (ESRD). Comparative study before and after hemodialysis]

PURPOSE

Contrasting data exist about the hemodialysis induced changes of ventricular diastolic and systolic functions in adults. Few data in children with end-stage renal disease (ESRD) are reported. The aim of the present study was to evaluate the effect of a single hemodialysis (HD) session on left ventricular (LV) systolic and diastolic function using conventional pulsed-Doppler echocardiography and pulsed tissue Doppler imaging (TDI) in hemodialysis children.

METHODS

Thirty-five children with chronic renal failure (15 males, aged 12.8+/-3.8 years) on maintenance hemodialysis underwent conventional 2D and Doppler Echo together with measurement of longitudinal mitral annular motion velocities. Echocardiographic parameters were obtained 30 minutes before and 30 minutes after HD. Paired data were compared.

RESULTS

Hemodialysis led to reduction in LV end-diastolic volume (p=0.001), end-systolic volume (p=0.05), left atrium area (p<0.0001), peak early (E wave) transmitral flow velocity (p=0.005), peak S velocity of pulmonary vein flow (p=0.002), aortic time velocity integral (p<0.0001) and aortic ejection time (p<0.0001). No significant change in Tei Index was observed after HD. Regarding TDI measures, velocities were not affected by preload reduction. Only the early diastolic velocities on the septal side of the mitral annulus decreased significantly (p=0.001) and the systolic velocities on the lateral side of the mitral annulus increased significantly (p=0.042) after hemodialysis.

CONCLUSIONS

Most of Doppler-derived indices of diastolic function are preload-dependent. TDI velocities and Tei Index were not or minimally affected by preload reduction in hemodialysis children.

Effect of maintenance hemodialysis on diastolic left ventricular function in end-stage renal disease

PURPOSE

To analyze the effect of maintenance hemodialysis on left ventricular diastolic function in patients with end-stage renal disease.

METHODS

Study population consisted of 42 patients with end-stage renal disease. Before an arteriovenous fistula was surgically created, the patients were evaluated by conventional and Doppler echocardiography and Doppler tissue imaging. Then, the patients undergoing hemodialysis treatment when the arteriovenous fistula was compleated. After the first hemodialysis session (mean 76.14 ± 11.37 days) the second echocardiographic evaluations were performed.

RESULTS

Mean age was 58 ± 13 years and 21 (%50) of the patients were female. After maintenance hemodialysis treatment; peak early (E) and peak late (A) diastolic mitral inflow velocities and E/A ratio were not significantly change however the deceleration time of E wave and left atrial diameter were significantly increased. Also there was no change in the early (Em) and late (Am) diastolic myocardial velocities and Em/Am ratios of lateral and septal walls of left ventricular. E/Em ratio was decreased insignificantly. Pulmonary vein velocities and right ventricular functions are remained almost unchanged after hemodialysis treatment.

DISCUSSION

The acute and long-term effect of hemodialysis on left ventricular diastolic function is unclearly. Patients with end-stage renal disease treatment with hemodialysis via arteriovenous fistula experience a variety of hemodynamic and metabolic abnormalities that predispose to alterations in left and right ventricular functions. The present study showed that left ventricular diastolic function except left atrial diameter and right ventricular functions were not significantly change, however left ventricular systolic functions were impaired after maintenance hemodialysis treatment in patients with end-stage renal disease.

CONCLUSION

It has been suggested that echocardiographic parameters are useful markers for evaluation of left ventricular and right ventricular functions in patients with end-stage renal disease. However, in patients with endstage renal disease treated with hemodialysis, repeated assessment of echocardiographic examinations to observe serial changes in left and right ventricular functions are not yet well established. In this study, we showed that acute changes of volume status and electrolytes and autonomic regulation by hemodialysis session did not affect left ventricular diastolic and right ventricular functions in a relatively long term.

Cardiac assessment in chronic kidney disease

Patients with chronic kidney disease are well recognized to develop a wide range of cardiac structural and functional abnormalities. These changes may be progressive and relate directly to a grossly aggravated risk of cardiovascular events and reduced survival. Although conventional methods of cardiac assessment have been shown to be useful, they are limited by insufficient sensitivity and specificity, to fully appreciate the overall degree of myocardial distress that is common in these patients. This article aims to review the use of established and emerging cardiac imaging tools and, in particular, their application in patients with chronic kidney disease.

Evidence of left ventricular systolic and diastolic dysfunction by color tissue Doppler imaging despite normal ejection fraction in patients on chronic hemodialysis program

BACKGROUND

Cardiovascular diseases are responsible for about half of deaths and are the major cause of mortality in hemodialysis patients. The aim of this study is to assess left ventricular (LV) longitudinal myocardial functions by color tissue Doppler imaging (TDI) in patients with chronic renal failure on a regular hemodialysis program.

METHODS

Thirty-one patients on a regular hemodialysis program (mean age 47 +/- 12 years; 17 males, 14 females) were included into the study. Twenty-three healthy subjects (mean age 44 +/- 8 years; 15 males, 8 females) were studied as a control group. The patients had been on maintenance hemodialysis for at least 1 month and hemodialysis sessions were three times per week. For color TDI, apical two- and four-chamber views of left ventricle were used. Sample volumes were placed on the mid-left ventricle in the inner half of the myocardium at the septum, lateral, inferior, and anterior walls. Peak LV strain, peak systolic strain rate, peak early diastolic strain rate, peak late diastolic strain rate, peak systolic tissue velocity, peak early diastolic tissue velocity, and peak late diastolic tissue velocity values were measured.

RESULTS

Mean peak LV strain, mean peak systolic strain rate, and mean peak systolic tissue velocity values were all lower in the hemodialysis group. Although mean peak late diastolic strain rate and mean peak late diastolic tissue velocity values were similar between the groups, mean peak early diastolic strain rate and mean peak early diastolic tissue velocity values were lower in the hemodialysis group.

CONCLUSION

Patients with chronic renal failure on regular hemodialysis program show significant alterations at LV longitudinal myocardial function parameters assessed by color TDI.

Three-dimensional echocardiographic analysis of left ventricular function during hemodialysis

BACKGROUND

The effects of hemodialysis (HD) on left ventricular (LV) function have been studied by various echocardiographic techniques (M-mode, 2D echocardiography). These studies are hampered by a low accuracy of measurements because of geometric assumptions regarding LV shape. Three-dimensional echocardiography (3DE) overcomes this limitation.

METHODS

We tested the feasibility of 3DE assessment of LV function during HD. Conventional biplane Simpson rule (BSR) and single plane area length method (SPM) for LV function analysis were used as a reference.

RESULTS

12 HD patients were studied and in 10 (83%) a total of 80 3D datasets were acquired. In 3 patients, one dataset (4%) was of insufficient quality and excluded from analysis. Correlation between SPM, BSR and 3DE for calculation of end-diastolic (EDV, r = 0.89 and r = 0.92, respectively), end-systolic volume (ESV, r = 0.92 and r = 0.93, respectively) and for ejection fraction (EF, r = 0.90 and r = 0.88, respectively) was moderate. Limits-of-agreement results for EDV and ESV were poor with confidence intervals larger than 30 ml. Both 2DE methods underestimated end-diastolic and end-systolic volume, while overestimating ejection fraction.

CONCLUSION

3DE is feasible for image acquisition during HD, which opens the possibility for accurate and reproducible measurement of LV function during HD. This may improve the assessment of the acute effect of HD on LV performance, and guide therapeutic strategies aimed at preventing intradialytic hypotension.