Association between Left Atrium Enlargement and Intradialytic Hypotension: Role of Diastolic Dysfunction in the Hemodynamic Complications during Hemodialysis

Usefulness of the heart rate variability test in predicting intradialytic hypotension in patients undergoing chronic haemodialysis

Background

Intradialytic hypotension (IDH) is the primary complication of haemodialysis (HD); however, its diverse pathophysiology and inconsistent definitions complicate its prediction. Despite attempts using the heart rate variability (HRV) test for IDH prediction, studies on its usefulness for predicting IDH diagnosed per the nadir 90 criterion are lacking. We aimed to evaluate HRV test efficacy and reproducibility in predicting IDH based on the nadir 90 criterion.

Methods

Seventy patients undergoing HD participated in this multicentre prospective observational study. The HRV test was performed during non-HD periods and IDH was monitored during 12 HD sessions. IDH was diagnosed according to the nadir 90 criterion, defined as a decrease in systolic blood pressure of ≤90 mmHg during HD. After monitoring, the HRV test was repeated. An HRV-IDH index was developed using multivariate logistic regression analysis employing HRV test parameters. The predictive power of the HRV-IDH index was analysed using the area under the receiver operating characteristics curve (AUROC). Reproducibility was evaluated using correlation analysis of two HRV tests on the same patient.

Results

There were 37 and 33 patients in the IDH and non-IDH groups, respectively. The HRV-IDH index predicted IDH occurrence with AUROCs of 0.776 and 0.803 for patients who had experienced at least one or repeated IDH episodes, respectively. Spearman's correlation coefficient for HRV-IDH indices was 0.859 for the first and second HRV tests.

Conclusions

The HRV test holds promise for predicting IDH, particularly for patients with recurring IDH diagnosed based on the nadir 90 criterion.

Left atrial reservoir strain is an outstanding predictor of adverse cardiovascular outcomes in patients undergoing maintenance hemodialysis: Assessment via three-dimensional speckle tracking echocardiography

Background

There is a paucity of literature focusing left atrium (LA) in patients undergoing maintenance hemodialysis (MHD).

Hypothesis

We used three‐dimensional speckle tracking echocardiography (3DSTE) to evaluate LA in MHD patients and to explore its predictive value for adverse outcomes.

Methods

Echocardiography was performed on 130 consecutively enrolled MHD patients without previous cardiac diseases. Conventional and 3DSTE parameters of LA were obtained. The MHD cohort was then followed and the end point was major adverse cardiovascular events (MACEs). LA strain indices, including reservoir strain (LASr), conduit strain (LAScd), and contractile strain (LASct), were measured and compared between patients with and without MACEs.

Results

Patients were prospectively followed up for a median of 40.5 (interquartile range: 26.3–48.0) months. During follow‐up, 43 patients met the end point. These patients had larger LA size and reduced LA strains (LA maximal volume indexed: 45.1 ± 11.9 vs. 33.8 ± 6.9ml/m²; LASr: 20.2 ± 3.5 vs. 27.2 ± 3.3%; LAScd: −12.3 ± 5.2 vs. −14.5±4.0%; LASct: −8.0 ± 4.2 vs. −13.2 ± 3.7%; all p<.05), compared with those without MACEs. Multivariable regression analysis showed LASr was the strongest predictor of MACEs (hazard ratio, 0.69; 95% confidence interval, 0.54–0.89; p=.004). Univarite Kaplan–Meier analysis revealed the incidence of MACEs in the impaired LASr (<24.2%) group was significantly higher than in the normal LASr group (log rank p<.001).

Conclusions

LASr derived from 3DSTE is an independent predictor of MACEs and cardiac death in MHD patients, superior to LV parameters and LA volume indices.

Predicting factors of intradialytic hypotension in the last half of hemodialysis therapy

Background

Intradialytic hypotension (IDH) is one of the most frequent complications of hemodialysis. IDH alters a patient’s quality of life and has a strong association with mortality. IDH mainly occurs when ultrafiltration during hemodialysis exceeds the pace of the plasma refill. Ultrasonography has been used to evaluate the intravascular volume status. We evaluated the association between IDH and baseline laboratory data or ultrasound findings during IDH during the latter half of a hemodialysis session.

Methods

Sixty-two patients who underwent hemodialysis were enrolled in this study. The peak early mitral inflow wave velocity (peak E-velocity), the inferior vena cava (IVC) dimensions, and number of B-lines were estimated at two time points (just after the start and at the midpoint of the hemodialysis session). We compared the parameters between the patients without IDH throughout the hemodialysis session (non-IDH group) and patients with IDH only during the latter half of the hemodialysis session (IDH in the latter half group).

Results

Of the 62 study participants, 28 patients were in non-IDH group, and 16 patients were in IDH in the latter half group. The serum sodium level was significantly lower in the IDH in the latter half group (135 ± 4 mEq/L) than in the non-IDH group (138 ± 4 mEq/L) (P = 0.015). The rate of decrease of the peak E-velocity was significantly higher in the IDH in the latter half group (0.33 ± 0.13) than in the non-IDH group (0.24 ± 0.14) (P = 0.037). The best cutoff point of the serum level of sodium was 137 mEq/L, with a sensitivity of 68.8% and specificity of 64.3%. The area under the receiver operating characteristic (ROC) curve was 0.71. The best cutoff point of the rate of decrease of the peak E-velocity was 0.295, with a sensitivity of 73.3% and a specificity of 71.4%. The area under the ROC curve was 0.71.

Conclusions

A low serum level of sodium at baseline and an early decrease in the peak E-velocity during hemodialysis may be related to intradialytic hypotension in the latter half of a hemodialysis session. Careful observation may be needed in the hemodialysis patients in whom the serum level of sodium is below 137 mEq/L or the rate of decrease of the peak E-velocity is over 0.295.

High ultrafiltration rate induced intradialytic hypotension is a predictor for cardiac remodeling: a 5-year cohort study

BACKGROUND

Intradialytic-hypotension (IDH) is a common complication of hemodialysis. High ultrafiltration rate (UFR) might lead to IDH. However, the relationships between UFR, IDH, and cardiac remodeling among hemodialysis patients in the long-term have not been deeply explored.

METHODS

This retrospective cohort study collected clinical and echocardiographic data. Patients were enrolled from 1 January 2014 to 31 March 2014 and were followed-up for 5-year. Those who suffered from more than four hypotensive events during three months (10% of dialysis treatments) were defined as the IDH group. Subgroup analysis was done according to the UFR of 10 ml/h/kg. Associations between UFR, IDH, and alterations of cardiac structure/function were analyzed.

RESULTS

Among 209 patients, 96 were identified with IDH (45.9%). The survival rate of IDH patients was lower than that of no-IDH patients (65.5% vs. 81.4%, p = .005). In IDH group, decreased ejection fraction (EF), larger left atrium diameter index (LADI), and left ventricular mass index (LVMI) (p < .05) were observed at the end of the follow-up. In multivariate logistic model, the interaction between UFR and IDH was notably associated with LVMI variation (OR = 1.37). After adjusting covariates, UFR was still an independent risk factor of LVMI variation (OR = 1.52) in IDH group. In subsequent analysis, we divided patients according to UFR 10 ml/h/kg. For IDH-prone patients, decreased EF, larger LADI, and LVMI (p < .05) were observed at the end of the study only in high-UFR group.

CONCLUSIONS

UFR and IDH have interactions on cardiac remodeling. High ultrafiltration rate induced IDH is a predictor for cardiac remodeling in long-term follow-up.

Intradialytic hypotension and associated factors among patients on maintenance hemodialysis: A single-center study in cameroon

Intradialytic hypotension (IDH), one of the most frequent acute complications of hemodialysis (HD), is associated with increased patient's morbidity and mortality. The aim of this study was to determine its prevalence and associated factors among patients on maintenance HD in Cameroon. This was a prospective longitudinal study carried out from June 20, to July 30, 2016 (5 weeks), including adult patients on HD >3 months at a tertiary hospital in Douala. During this period, patients were followed up at each HD session, and their blood pressure and occurrence of clinical events possibly related to IDH were recorded. In this study, IDH was defined as a decrease in systolic BP by >20 mm Hg or a decrease in mean arterial pressure by >10 mm Hg, associated to a clinical event. Logistic regression analysis was used to determine associated factors. We included 104 patients (69 males) with a mean age of 50.74 ± 15.18 years and a median duration on HD of 30.5 (interquartile range: 12.25-58.75) years. Hypertension 99/104 (95.2%) and diabetes 32/104 (30.8%) were the main comorbidities encountered. A total of 1032 HD sessions were followed up with an average of 9.88 ± 1.57 sessions per patient. IDH occurred in 11.6% of HD sessions. Associated factors were age, female sex, HIV infection, feeding during dialysis, and use of antihypertensive drug during or within 2 h before dialysis. The prevalence of IDH in our study was low. Associated factors were mainly related to patient's characteristics and comorbidities.

Left Atrial Remodeling Assessed by Cardiac MRI after Conversion from Conventional Hemodialysis to In-Centre Nocturnal Hemodialysis

BACKGROUND

Left atrial (LA) volume is a well-established cardiovascular prognosticator in patients with end-stage renal disease. Although dialysis intensification is associated with left ventricular mass regression, there are limited data regarding LA remodeling. Using cardiac magnetic resonance imaging (CMR), we examined changes in LA size and function relative to ventricular remodeling and cardiac biomarkers after dialysis intensification.

METHODS

In this prospective 2-centre cohort study, 37 patients receiving conventional hemodialysis (CHD, 4 h/session, 3×/week) were converted to in-centre nocturnal hemodialysis (INHD 7-8 h/session, 3×/week); 30 patients remained on CHD. CMR and biomarkers were performed at baseline and repeated at 52 weeks.

RESULTS

After 52 weeks, there were no significant changes in the LA volumes or LA ejection fraction (EF) within either the CHD or INHD group, and no significant differences between the two groups. Correlations existed between changes in LA and LV end-diastolic volume index (EDVi, Spearman's r = 0.69, p < 0.001), LA and LV end-systolic volume index (ESVi, r = 0.44, p = 0.001), LAEF and LVEF (r = 0.28, p = 0.04), LA and RV EDVi (r = 0.51, p < 0.001), LA and RV ESVi (r = 0.29, p = 0.039), and LA ESVi and LV mass index (r = 0.31, p = 0.02). At baseline, indexed LA volumes positively correlated with NT-proBNP, whereas LAEF negatively correlated with NT-proBNP and Troponin I. After 52 weeks, changes in biomarker levels did not correlate with changes in LA volume or EF.

CONCLUSION

There was no significant change in LA size or systolic function after conversion to INHD. The significant correlations between LA and ventricular remodeling and cardiac biomarkers suggest common underlying pathophysiologic mechanisms.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00718848.

Intradialytic Hypotension as an Independent Risk Factor for Long-Term Mortality in Maintaining Hemodialysis Patients: A 5-Year Follow-Up Cohort Study

AIMS

This study aimed to assess risk factors of intradialytic hypotension (IDH) and the association of prognosis and IDH among maintenance hemodialysis (MHD) patients.

METHODS

Among 293 patients, 117 were identified with IDH (more than 4 hypotensive events during 3 months). The association between IDH and survival was evaluated.

RESULTS

The incidence of IDH was 39.9%. Age, ultrafiltration rate, N-terminal pro-B-type natriuretic peptide (NT-proBNP), albumin, β2-microglobulin (β2MG), and aortic root inside diameter (AoRD) were independently associated with IDH. During the 5-year follow-up, 84 patients died with a mortality rate 5.2 per 100 person-year. IDH-prone patients had a higher all-cause mortality rate. IDH and left ventricular mass index were independent risk factors for death (HR 1.655, 95% CI 1.061-2.580; HR 1.008, 95% CI 1.001-1.016).

CONCLUSION

IDH is an independent risk factor for long-term mortality in MHD patients. Patients with older age, high ultrafiltration rate, high level of serum NT-proBNP and β2MG, hypoalbuminemia, and shorter AoRD are at high risk of IDH.

Interplay of volume, blood pressure, organ ischemia, residual renal function, and diet: certainties and uncertainties with dialytic management

Extracellular fluid volume overload and its inevitable consequence, hypertension, increases cardiovascular mortality in the long term by leading to left ventricular hypertrophy, heart failure, and ischemic heart disease in dialysis patients. Unlike antihypertensive medications, a strict volume control strategy provides optimal blood pressure control without need for antihypertensive drugs. However, utilization of this strategy has remained limited because of several factors, including the absence of a gold standard method to assess volume status, difficulties in reducing extracellular fluid volume, and safety concerns associated with reduction of extracellular volume. These include intradialytic hypotension; ischemia of heart, brain, and gut; loss of residual renal function; and vascular access thrombosis. Comprehensibly, physicians are hesitant to follow strict volume control policy because of these safety concerns. Current data, however, suggest that a high ultrafiltration rate rather than the reduction in excess volume is related to these complications. Restriction of dietary salt intake, increased frequency, and/or duration of hemodialysis sessions or addition of temporary extra sessions during the process of gradually reducing postdialysis body weight in conventional hemodialysis and discontinuation of antihypertensive medications may prevent these complications. We believe that even if an unwanted effect occurs while gradually reaching euvolemia, this is likely to be counterbalanced by favorable cardiovascular outcomes such as regression of left ventricular hypertrophy, prevention of heart failure, and, ultimately, cardiovascular mortality as a result of the eventual achievement of normal extracellular fluid volume and blood pressure over the long term.

Impact of extracorporeal blood flow rate on blood pressure, pulse rate and cardiac output during haemodialysis

BACKGROUND

If blood pressure (BP) falls during haemodialysis (HD) [intradialytic hypotension (IDH)] a common clinical practice is to reduce the extracorporeal blood flow rate (EBFR). Consequently the efficacy of the HD (Kt/V) is reduced. However, only very limited knowledge on the effect of reducing EBFR on BP exists and data are conflicting. The aim of this study was to evaluate the effect and the potential mechanism(s) involved by investigating the impact of changes in EBFR on BP, pulse rate (PR) and cardiac output (CO) in HD patients with arteriovenous-fistulas (AV-fistulas).

METHODS

We performed a randomized, crossover trial in 22 haemodynamically stable HD patients with AV-fistula. After a conventional HD session each patient was examined during EBFR of 200, 300 and 400 mL/min in random order. After 15 min when steady state was achieved CO, BP and PR were measured at each EFBR, respectively.

RESULTS

Mean (SD) age was 71 (11) years. Systolic BP was significantly higher at an EBFR of 200 mL/min as compared with 300 mL/min [133 (23) versus 128 (24) mmHg; P < 0.05], but not as compared with 400 mL/min [133 (23) versus 130 (19) mmHg; P = 0.20]. At EBFR of 200, 300 and 400 mL/min diastolic BP, mean arterial pressure, PR and CO remained unchanged.

CONCLUSION

Our study does not show any consistent trend in BP changes by a reduction in EBFR. Reduction in EBFR if BP falls during IDH is thus not supported. However, none of the patients experienced IDH. Further studies are required to evaluate the impact of changes in EBFR on BP during IDH.

Frequency of intradialytic hypotensive episodes: old problem, new insights

Symptomatic intradialytic hypotension (IDH) continues to be an important complication of hemodialysis treatment. There is some evidence that besides an IDH episode, repeated episodes could represent an even more important independent risk factor for mortality in hemodialysis patients. A retrospective cross-sectional study was performed to study 18 dialysis treatments in 43 patients during 6 weeks. Relationships of IDH episodes with baseline variables were examined using a Poisson regression model (generalized linear model). IDH was frequent (93% of patients) and highly variable by patient (0%-100%). Multivariate analysis showed that patients who experienced frequent hypotensive episodes had a lower dry weight (90% confidence interval [CI]: 0.95-0.99), higher phosphorus levels (90% CI: 1.07-1.47), greater prevalence of diabetes mellitus (90% CI: 1.11-2.71), and hypertension (90% CI: 1.04-2.45). Dry weight, hypertension, and phosphorus levels are modifiable risk factors to possibly reduce the rate of IDH episodes. The potential protective role of phosphorus warrants further investigation.

Intradialytic hypotension and cardiac remodeling: a vicious cycle

Hemodynamic instability during hemodialysis is a common but often underestimated issue in the nephrologist practice. Intradialytic hypotension, namely, a decrease of systolic or mean blood pressure to a certain level, prohibits the safe and smooth achievement of ultrafiltration and solute removal goal in chronic dialysis patients. Studies have elucidated the potential mechanisms involved in the development of Intradialytic hypotension, including excessive ultrafiltration and loss of compensatory mechanisms for blood pressure maintenance. Cardiac remodeling could also be one important piece of the puzzle. In this review, we intend to discuss the role of cardiac remodeling, including left ventricular hypertrophy, in the development of Intradialytic hypotension. In addition, we will also provide evidence that a bidirectional relationship might exist between Intradialytic hypotension and left ventricular hypertrophy in chronic dialysis patients. A more complete understanding of the complex interactions in between could assist the readers in formulating potential solutions for the reduction of both phenomena.

Left ventricular diastolic dysfunction as a predictor of rapid decline of residual renal function in patients with peritoneal dialysis

BACKGROUND

The aim of this study was to evaluate whether diastolic dysfunction at the start of dialysis could influence renal and cardiovascular survival rates in 82 patients undergoing peritoneal dialysis.

METHODS

Diastolic dysfunction was determined using left ventricular hypertrophy, the ratio of early peak transmitral inflow velocity to peak diastolic mitral annular velocity (E/E'), and left atrial volume index (LAVI). Residual renal function (RRF) was measured with 24-hour urine collections at baseline (within 1 month of beginning peritoneal dialysis) and thereafter at 6-month intervals for 2 years. To evaluate the long-term prognostic significance of diastolic dysfunction, the 4-year cardiac event-free survival was also evaluated.

RESULTS

The median slope of RRF decline was -0.07 mL/min/mo/1.73 m(2). Forty-five patients (54.9%) with rapid RRF declines (< -0.07 mL/min/mo/1.73 m(2)) had a higher prevalence of diabetes and eccentric left ventricular hypertrophy, as well as significantly elevated E/E' ratios and LAVIs. There was a close relationship between baseline E/E' ratio (r = -0.221, P = .048), LAVI (r = -0.276, P = .015), and RRF decline rate, and both E/E' > 15 (odds ratio, 3.61; 95% confidence interval, 1.07-12.12) and LAVI > 32 mL/m(2) (odds ratio, 3.54; 95% confidence interval, 1.08-11.58) were significant independent predictors of the loss of RRF. Furthermore, E/E' > 15 also provided additional prognostic value in predicting future cardiac events (hazard ratio, 6.74; 95% confidence interval, 1.07-12.12; P = .023).

CONCLUSIONS

Left ventricular diastolic dysfunction may be a significant predictor of rapid decline in RRF and adverse cardiac outcomes in patients starting peritoneal dialysis.

Blood pressure and sympathetic nerve tone relation during hemodialysis may reflect cardiovascular dysfunction

BACKGROUND

The blood pressure response to the rapid removal of fluid during hemodialysis is complex and the pathophysiological mechanisms underlying intradialytic hypotension are not clear and sometimes these mechanisms render dialysis difficult to continue.

PURPOSE

We analyzed the changes in blood pressure and sympathetic nerve tone and attempted to clarify whether the dynamic pattern of this relationship reflects cardiovascular dysfunction.

METHODS

The dynamic pattern of sympathetic nerve activity throughout dialysis was analyzed by frequency analysis of RR intervals recorded by 24 hours Holter electrocardiography in 64 patients and 3 minutes ECG every 15 minutes during dialysis in 121 stable end-stage renal failure patients who underwent maintenance hemodialysis. Blood pressure and fluid volume removed was measured every 15-30 minutes during dialysis and the average value of the ratio of low to high frequency components (LF/HF) was calculated as an index of sympathetic nerve tone. The relationship between removed fluid volume, systolic blood pressure (Bp) and LF/HF was analyzed.

RESULTS

The patients were classified into 3 groups based on the correlation between the LF/HF and Bp as follows: positive (52 cases), inverse (54 cases), and not significant (NS; 61 cases). Eighteen patients who showed multiple arrhythmias, atrial fibrillation and other artifacts or noises were eliminated as they were inadequate for frequency analysis of RR intervals. The positive group was characterized by a hypotension-resistant response with a low LF/HF, whereas the inverse group was characterized by a hypotension-prone response with high LF/HF. These results suggest that cardiovascular dysfunction is responsible for the inverse correlation.

CONCLUSION

Analysis of the relationship between sympathetic nerve tone and Bp is effective in predicting the existing of cardiovascular dysfunction.