Effects of hemodialysis on the cardiovascular system: quantitative analysis using wave intensity wall analysis and tissue velocity imaging

Designing an Implementable Clinical Prediction Model for Near-Term Mortality and Long-Term Survival in Patients on Maintenance Hemodialysis

RATIONALE & OBJECTIVE

The life expectancy of patients treated with maintenance hemodialysis (MHD) is heterogeneous. Knowledge of life-expectancy may focus care decisions on near-term versus long-term goals. The current tools are limited and focus on near-term mortality. Here, we develop and assess potential utility for predicting near-term mortality and long-term survival on MHD.

STUDY DESIGN

Predictive modeling study.

SETTING & PARTICIPANTS

42,351 patients contributing 997,381 patient months over 11 years, abstracted from the electronic health record (EHR) system of midsize, nonprofit dialysis providers.

NEW PREDICTORS & ESTABLISHED PREDICTORS

Demographics, laboratory results, vital signs, and service utilization data available within dialysis EHR.

OUTCOME

For each patient month, we ascertained death within the next 6 months (ie, near-term mortality) and survival over more than 5 years during receipt of MHD or after kidney transplantation (ie, long-term survival).

ANALYTICAL APPROACH

We used least absolute shrinkage and selection operator logistic regression and gradient-boosting machines to predict each outcome. We compared these to time-to-event models spanning both time horizons. We explored the performance of decision rules at different cut points.

RESULTS

All models achieved an area under the receiver operator characteristic curve of≥0.80 and optimal calibration metrics in the test set. The long-term survival models had significantly better performance than the near-term mortality models. The time-to-event models performed similarly to binary models. Applying different cut points spanning from the 1st to 90th percentile of the predictions, a positive predictive value (PPV) of 54% could be achieved for near-term mortality, but with poor sensitivity of 6%. A PPV of 71% could be achieved for long-term survival with a sensitivity of 67%.

LIMITATIONS

The retrospective models would need to be prospectively validated before they could be appropriately used as clinical decision aids.

CONCLUSIONS

A model built with readily available clinical variables to support easy implementation can predict clinically important life expectancy thresholds and shows promise as a clinical decision support tool for patients on MHD. Predicting long-term survival has better decision rule performance than predicting near-term mortality.

PLAIN-LANGUAGE SUMMARY

Clinical prediction models (CPMs) are not widely used for patients undergoing maintenance hemodialysis (MHD). Although a variety of CPMs have been reported in the literature, many of these were not well-designed to be easily implementable. We consider the performance of an implementable CPM for both near-term mortality and long-term survival for patients undergoing MHD. Both near-term and long-term models have similar predictive performance, but the long-term models have greater clinical utility. We further consider how the differential performance of predicting over different time horizons may be used to impact clinical decision making. Although predictive modeling is not regularly used for MHD patients, such tools may help promote individualized care planning and foster shared decision making.

The diastolic function abnormalities in hemodialysis session: a two-dimensional speckle tracking echocardiographic (2DSTE) study

Hemodialysis (HD) decreases preload and its acute effect on the diastolic function is still controversial even with the introduction of new non-volume-dependent tissue Doppler echocardiographic indices. This study is designed to evaluate these acute changes following HD sessions. We enrolled 39 patients receiving standard thrice weekly HD for more than 6 months and performed two dimensional speckle tracking echocardiography (2DSTE) and tissue Doppler studies with a standard cardiac ultrasound device shortly before and after HD. We observed significant changes in most of the transmitral flow and tissue Doppler echocardiographic parameters after HD. The left atrial volume index, left ventricular mass index, mitral E, mitral E/A, and lateral annular E/é levels decreased after HD (p: < 0.001, p: 0.026, p: < 0.001, p: 0.011, p: < 0.001, respectively). Medial á, medial myocardial performance index (MPI), medial ś, lateral ś, and lateral MPI values increased significantly after HD (p: 0.049, p: 0.007, p: 0.001, p: < 0.001, p: 0.01, respectively). Diastolic parameters like diastolic strain ratio early diastole (DSRE), diastolic strain ratio late diastole (DSRA), E/DSRE, and E/DSRA did not change significantly after HD (p: 0.716, p: 0.117, p: 0.114, and p: 0.211, respectively). The global longitudinal strain value obtained with 2DSTE worsened after HD (- 18.4 ± 4.0 before vs - 15.9 ± 5.4 after HD, p: 0.011). Transmitral flow and tissue Doppler parameters changed significantly after HD while the change in 2DSTE findings was not significant. The diastolic measurements made with 2DSTE may be less volume and cardiac preload dependent compared to conventional echocardiography and this may explain the difference.

Evaluation of left ventricular systolic functions in two-dimensional speckle-tracking echocardiography in children with chronic renal failure

BACKGROUND AND AIM

Chronic kidney disease may lead to left ventricular dysfunction. Early detection of cardiovascular disease in children with chronic kidney disease is essential to prevent cardiovascular morbidity and mortality in early adulthood. This study aimed to document the dysfunction using methods such as two-dimensional speckle-tracking echocardiography in the early stage.

METHODS

A total of 34 patients diagnosed with chronic kidney disease (mean age ± standard deviation, 10.5 ± 4.1 years) and 37 sex- and age-matched (mean age 9.8 ± 4.2 years) healthy controls were studied. The results of the two groups were compared along with those of the published studies.

RESULTS

The echocardiography measurements had no significant difference in the end-diastolic and end-systolic diameter values of left ventricular, ejection fraction, shortening fraction, mitral E value, mitral A value, and E/A ratio between the groups. Pulmonary artery systolic and diastolic pressure and left ventricular mass index were significantly higher in the patient group (p < 0.01). The longitudinal global strain values in the apical four-chamber, three-chamber, and two-chamber views and the total global strain values were significantly lower in the patients (p < 0.01). The circumferential global strain values in the apical, mid, basal, and total global strain were lower in the patient group, but this difference was statistically significant in the apical global and total global strain values (p < 0.05).

CONCLUSIONS

Speckle-tracking echocardiography might help identify subclinical left ventricular dysfunction in patients with chronic kidney disease with unremarkable conventional echocardiography.

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.

Impact of hemodialysis on cardiovascular system assessed by pulse wave analysis

Valuable information about cardiovascular system can be derived from the shape of aortic pulse wave being the result of reciprocal interaction between heart and vasculature. Pressure profiles in ascending aorta were obtained from peripheral waveforms recorded non-invasively (SphygmoCor, AtCor Medical, Australia) before, during and after hemodialysis sessions performed after 3-day and 2-day interdialytic intervals in 35 anuric, prevalent hemodialysis patients. Fluid status was assessed by Body Composition Monitor (Fresenius Medical Care, Bad Homburg, Germany) and online hematocrit monitoring device (CritLine, HemaMetrics, Utah). Systolic pressure and ejection duration decreased during dialysis. Augmentation index remained stable at 30 ± 13% throughout hemodialysis session despite the decrease of augmented pressure and pulse height. Subendocardial viability ratio (SEVR) determined after 3-day and 2-day interdialytic intervals increased during the sessions by 43.8 ± 26.6% and 26.1 ± 25.4%, respectively. Hemodialysis performed after 3-day and 2-day interdialytic periods reduced significantly overhydration by 2.4 ± 1.0 L and 1.8 ± 1.2 L and blood volume by 16.3 ± 9.7% and 13.7 ± 8.9%, respectively. Intradialytic increase of SEVR correlated with ultrafiltration rate (R = 0.39, p-value < 0.01), reduction in overhydration (R = -0.57, p-value < 0.001) and blood volume drop (R = -0.38, p-value < 0.01). The strong correlation between the decrease of overhydration during hemodialysis and increase in SEVR confirmed that careful fluid management is crucial for proper cardiac function. Hemodialysis affected cardiovascular system with the parameters derived from pulse-wave-analysis (systolic and augmented pressures, pulse height, ejection duration, SEVR) being significantly different at the end of dialysis from those before the session. Combination of pulse-wave-analysis with the monitoring of overhydration provides a new insight into the impact of hemodialysis on cardiovascular system.

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.

Use of wave intensity analysis of carotid arteries in identifying and monitoring left ventricular systolic function dynamics in rabbits

Wave intensity analysis (WIA) of the carotid artery was conducted to determine the changes that occur in left ventricular systolic function after administration of doxorubicin in rabbits. Each randomly selected rabbit was subject to routine ultrasound, WIA of the carotid artery, cardiac catheterization and pathologic examination every week and was followed for 16 wk. The first positive peak (WI1) of the carotid artery revealed that left ventricular systolic dysfunction occurred earlier than conventional indexes of heart function. WI1 was highly, positively correlated with the maximum rate of rise in left ventricular pressure in cardiac catheterization (r = 0.94, p < 0.01) and moderately negatively correlated with the apoptosis index of myocardial cells, an indicator of myocardial damage (r = -0.69, p < 0.01). Ultrasound WIA of the carotid artery sensitively reflects early myocardial damage and cardiac function, and the result is highly consistent with cardiac catheterization findings and the apoptosis index of myocardial cells.

Left ventricular strain and peak systolic velocity: responses to controlled changes in load and contractility, explored in a porcine model

BACKGROUND

Tissue velocity echocardiography is increasingly used to evaluate global and regional cardiac function. Previous studies have suggested that the quantitative measurements obtained during ejection are reliable indices of contractility, though their load-sensitivity has been studied in different settings, but still remains a matter of controversy. We sought to characterize the effects of acute load change (both preload and afterload) and change in inotropic state on peak systolic velocity and strain as a measure of LV contractility.

METHODS

Thirteen anesthetized juvenile pigs were studied, using direct measurement of left ventricular pressure and volume and transthoracic echocardiography. Transient inflation of a vena cava balloon catheter produced controlled load alterations. At least eight consecutive beats in the sequence were analyzed with tissue velocity echocardiography during the load alteration and analyzed for change in peak systolic velocities and strain during same contractile status with a controlled load alteration. Two pharmacological inotropic interventions were also included to generate several myocardial contractile conditions in each animal.

RESULTS

Peak systolic velocities reflected the drug-induced changes in contractility in both radial and longitudinal axis. During the acute load change, the peak systolic velocities remain stable when derived from signal in the longitudinal axis and from the radial axis. The peak systolic velocity parameter demonstrated no strong relation to either load or inotropic intervention, that is, it remained unchanged when load was systematically and progressively varied (peak systolic velocity, longitudinal axis, control group beat 1-5.72 ± 1.36 with beat 8-6.49 ± 1.28 cm/sec, 95% confidence interval), with the single exception of the negative inotropic intervention group where peak systolic velocity decreased a small amount during load reduction (beat 1-3.98 ± 0.92 with beat 8-2.72 ± 0.89 cm/sec). Systolic strain, however, showed a clear degree of load-dependence.

CONCLUSIONS

Peak systolic velocity appears to be load-independent as tested by beat-to-beat load reduction, while peak systolic strain appears to be load-dependent in this model. Peak systolic velocity, in a controlled experimental model where successive beats during load alteration are assessed, has a strong relation to contractility. Peak systolic velocity, but not peak strain rate, is largely independent of load, in this model. More study is needed to confirm this finding in the clinical setting.