Tissue Doppler velocity is not totally preload-independent: a study in a uremic population after hemodialysis

Changes in left ventricular and atrial mechanics and function after dialysis in patients with end-stage renal disease

Background

Hemodialysis (HD) can influence end-stage renal disease (ESRD) patients' circulatory system. The present study aimed to evaluate the effect of volume depletion on left ventricular (LV) and left atrial (LA) function and determine the volume-independent parameters before and after HD in patients with ESRD.

Methods

Between January 2018 and January 2019, we recruited long-term HD patients (n=40, 51.0±16.4 years), excluding those with structural cardiac disease. Echocardiographic parameters, including LV and LA volumes, flow Doppler, pulsed tissue Doppler, and speckle tracking echocardiography (STE) before and after HD (within 24 h), were examined, and the values were compared.

Results

Following HD, alteration in LV end-systolic volume was not detected, whereas LV end-diastolic volume (90.18±23.91 vs. 84.21±23.54 mL, P=0.036) and LV ejection fraction (LVEF; 64.63%±6.56% vs. 62.84%±6.56%, P=0.049) decreased. Peak early diastolic trans-mitral flow velocity (E-wave; 82.22±20.13 vs. 72.43±18.32 cm/s, P<0.001), peak early diastolic tissue Doppler velocity (e'; 6.45±1.88 vs. 5.77±1.63 cm/s, P<0.001) at the septal side of the mitral annulus, the ratio of early to late Doppler velocities of diastolic mitral inflow (0.90±0.27 vs. 0.79±0.23, P<0.001), and the average E/e' ratio (12.54±4.08 vs. 11.28±4.52, P=0.049) decreased significantly. No significant difference was found in peak blood flow velocity at the mitral valve during late diastole and e' at the lateral side of the mitral annulus after HD. LA volume index (35.55±12.61 vs. 30.22±9.80 mL/m², P<0.001), tricuspid regurgitation velocity (260.11±36.54 vs. 242.37±32.22 cm/s, P=0.002), and pulmonary artery systolic pressure (33.63±11.29 vs. 29.94±7.80 mmHg, P=0.006) significantly decreased. LV global longitudinal systolic strain (GLS) of 4-chamber view (-24.37%±3.02% vs. -23.38%±3.33%, P=0.019), rather than global circumferential systolic strain, exhibited significant change after HD. Significant changes were also found in LV longitudinal early diastolic strain rate (LSRe; 1.17±0.25 vs. 1.05±0.24 s^-1, P<0.001) and early diastolic global radial velocity (Ve; 2.62±0.59 vs. 2.25±0.67 cm/s, P=0.011) after HD, but not in other strain rates and global radial velocity measurements. LA maximal volume (35.55±12.61 vs. 30.22±9.80 mL/m², P<0.001), LA total emptying fraction (54.19%±10.39% vs. 49.63%±11.05%, P=0.009), and LA passive emptying fraction (32.23%±12.86% vs. 26.81%±9.28%, P=0.004) decreased significantly after HD, while LA minimal volume, the volume at the onset of atrial systole, and LA active emptying fraction after HD were not significantly different.

Conclusions

Most indices of systolic (LVEF and GLS of 4-chamber view) and early diastolic function (E-wave, e', LSRe, global radial Ve, and LA passive emptying fraction) were preload dependent. Late diastolic indices, including LV late diastolic global longitudinal strain rate, late diastolic global radial velocity, and LA active emptying fraction, did not change with volume depletion.

Effect of preload on left atrial function: evaluated by tissue Doppler and strain imaging

AIMS

Both strain and strain rate (SR) measure the regional myocardial deformation and can assess phasic left atrial (LA) function. However, there is still a lack of evidence for their volume independency. In this study, strain and SR determined by tissue Doppler imaging were used to evaluate the effect of preload reduction in end-stage renal disease patients who were undergoing regular haemodialysis (HD).

METHODS AND RESULTS

Forty-one subjects who underwent transthoracic echocardiography just before and after HD were enrolled. LA strain was measured during late systole, and LA peak tissue velocity and SR were measured during systole and during early and late diastolic periods. The values of tissue velocity, strain, and SR were obtained in the basal septal, lateral, inferior, and anterior walls of the LA. The mean strain value was 23.89 ± 7.29% at baseline and decreased to 21.88 ± 5.85% after HD (P = 0.019). SR during systole (before HD 1.55 ± 0.40; after HD 1.38 ± 0.35, P = 0.001) and early diastole (before HD -1.41 ± 0.54; after HD -1.16 ± 0.45, P = 0.001) also changed. However, the acute preload change caused by HD did not affect the peak tissue velocity (before HD -6.34 ± 1.58 cm/s; after HD -6.46 ± 1.54 cm/s, P = 0.436) and the SR (before HD -1.36 ± 0.45/s; after HD -1.34 ± 0.29/s, P = 0.621) measured during late diastole.

CONCLUSION

Both tissue velocity and SR during late diastole, representing the contractile function of the LA, are relatively preload-independent parameters and are available for the evaluation of the LA function.

Effect of food intake on commonly used pulsed Doppler and tissue Doppler measurements

OBJECTIVE

This study evaluates the effect of food intake on commonly used pulsed Doppler and tissue Doppler measurements.

METHODS

Twenty-three healthy subjects aged 25.6 ± 4.5 years were investigated. A wide selection of pulsed Doppler and tissue Doppler variables were measured before a standardized meal as well as and 30 and 110 minutes afterwards.

RESULTS

The following variables increased significantly (P < 0.05) 30 minutes after food intake: left ventricular stroke volume, left ventricular cardiac output, left ventricular outflow velocity-time integral, peak of early diastolic (E) and late diastolic (A) mitral flow velocities, pulmonary vein peak velocities in systole (S) and in diastole (D), S/D, pulsed tissue Doppler peak systolic velocities, and late diastolic velocities. Deceleration time of E-wave decreased significantly (P < 0.05). The change in measured variables between fasting and 30 minutes after the food intake ranged from 7% to 28%. There were no significant (P > 0.05) changes in E/A, early diastolic tissue Doppler velocities (e'), and E/e'. Most, but not all variables returned to baseline values 110 minutes after food intake.

CONCLUSIONS

This study shows that food intake affects several echocardiographic variables used to routinely assess diastolic function and hemodynamics. Further studies are warranted in older healthy subjects and in patients with various cardiac diseases to determine whether the findings are reproducible in such populations.

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.

Benefit of warm water immersion on biventricular function in patients with chronic heart failure

Background

Regular physical activity and exercise are well-known cardiovascular protective factors. Many elderly patients with heart failure find it difficult to exercise on land, and hydrotherapy (training in warm water) could be a more appropriate form of exercise for such patients. However, concerns have been raised about its safety.

The aim of this study was to investigate, with echocardiography and Doppler, the acute effect of warm water immersion (WWI) and effect of 8 weeks of hydrotherapy on biventricular function, volumes and systemic vascular resistance. A secondary aim was to observe the effect of hydrotherapy on brain natriuretic peptide (BNP).

Methods

Eighteen patients [age 69 ± 8 years, left ventricular ejection fraction 31 ± 9%, _peakVO₂ 14.6 ± 4.5 mL/kg/min] were examined with echocardiography on land and in warm water (34°C).

Twelve of these patients completed 8 weeks of control period followed by 8 weeks of hydrotherapy twice weekly.

Results

During acute WWI, cardiac output increased from 3.1 ± 0.8 to 4.2 ± 0.9 L/min, LV tissue velocity time integral from 1.2 ± 0.4 to 1.7 ± 0.5 cm and right ventricular tissue velocity time integral from 1.6 ± 0.6 to 2.5 ± 0.8 cm (land vs WWI, p < 0.0001, respectively). Heart rate decreased from 73 ± 12 to 66 ± 11 bpm (p < 0.0001), mean arterial pressure from 92 ± 14 to 86 ± 16 mmHg (p < 0.01), and systemic vascular resistance from 31 ± 7 to 22 ± 5 resistant units (p < 0.0001).

There was no change in the cardiovascular response or BNP after 8 weeks of hydrotherapy.

Conclusion

Hydrotherapy was well tolerated by all patients. The main observed cardiac effect during acute WWI was a reduction in heart rate, which, together with a decrease in afterload, resulted in increases in systolic and diastolic biventricular function. Although 8 weeks of hydrotherapy did not improve cardiac function, our data support the concept that exercise in warm water is an acceptable regime for patients with heart failure.

Tissue velocities, strain, and strain rate for echocardiographic assessment of ventricular function in congenital heart disease

During the last decade tissue Doppler and myocardial deformation imaging has been introduced to quantify myocardial function in patients with congenital heart disease. These methods could have potential benefits for patients where the anatomy makes it difficult to quantify ventricular function using M-mode or two-dimensional volumetric techniques. In this overview, the potential benefits as well as limitations of the techniques are discussed. Looking directly into the myocardium renders the techniques geometry-independent, allowing the quantification of right ventricular as well as univentricular systolic function. The limitations include the influence of variable loading conditions as well as different methodological problems.

Preload dependence of Doppler tissue imaging-derived indices in adolescents

Doppler tissue imaging (DTI) has been proposed as a tool for evaluation of diastolic function. Controversy exists regarding whether DTI measurements are influenced by preload. To determine the influence of preload reduction on DTI, we studied 17 patients (mean age 17 +/- 1.82 years) with end-stage renal disease and without overt heart disease, using DTI before and after hemodialysis (HD). Peak systolic (S), peak early diastolic (Ea), and peak late diastolic (Aa) velocities, and tissue Doppler-derived Tei index (the sum of the isovolumetric contraction and relaxation times divided by the ejection time: TDE-Tei), were determined for each patient from the septum, and lateral mitral and lateral tricuspid annuluses. The Ea of the mitral annulus (12.47 +/- 4.51 cm/s to 10.71 +/- 5.18 cm/s, P = 0.023), isovolumetric contraction time (ICT) of the mitral annulus (85.29 +/- 33.66 ms to 68.76 +/- 17.24 ms, P = 0.031) and Aa of the lateral tricuspid annulus (15.94 +/- 6.46 cm/s to 12.47 +/- 3.85 cm/s, P = 0.044) decreased significantly after HD. With weight loss of more than 1.5 kg, significant changes in the TDE-Tei index of the septum was observed (P = 0.036). From these findings, it is concluded that the Ea of the mitral annulus and the Aa of the tricuspid annulus are decreased by acute preload reduction. The TDE-Tei index is affected by preload reduction of more than 1.5 kg; therefore, it seems necessary to consider the preload status of HD patients when myocardial function is assessed by DTI.