post-HD Blood Pressure Research Articles

Machine learning models to predict post-dialysis blood pressure in children and young adults on maintenance hemodialysis

Hypertension is associated with significant cardiovascular morbidity. Blood pressure (BP) control on maintenance hemodialysis (HD) is strongly impacted by volume status. The objective of this study was to assess whether machine learning (ML) is effective in predicting post-HD BP in children and young adults on HD. We collected data on BP, IDWG, pulse, and weights for patients on maintenance HD (> 3 months). Input features included DW, pre-post weight difference, IDWG and pre-HD BP. Seven models were trained and tuned using open-source libraries. Model performance was evaluated using time-series cross-validation on a rolling basis (3–12 month training, 1-day testing). Various regression scores were compared between models. Data for 35 patients (14,375 HD sessions) were analyzed. Extreme gradient boosting (XGB) and vector autoregression with exogenous regressors (VARX) achieved better accuracy in predicting post-dialysis systolic BP than K-nearest neighbor, support vector regression (SVR) with radial basis function kernel and random forest (p < 0.001 for each). The differences in accuracy between XGB, VARX, SVR with linear kernel, random forest and linear regression were not significant. Using clinical parameters, ML models may be useful in predicting post-HD BP, which may help guide DW adjustment and optimizing BP control for maintenance HD patients.

Effect of low dialysate sodium in the management of intradialytic hypertension in maintenance hemodialysis patients: A single-center Indian experience.

High dialysate sodium is a significant contributor to intradialytic hypertension (IDH) in maintenance hemodialysis patients. In this study, we aimed to study the effect of low dialysate sodium on IDH in Indian hemodialysis patients. Fifty patients on maintenance hemodialysis for atleast 3 months with episodes of IDH were enrolled in this study. The study was performed in two different stages. In the first phase, patients were dialyzed with standard dialysate sodium (140 mEq/L) for eight consecutive sessions and in the second phase, they were dialyzed with low sodium dialysate (136 mEq/L) for eight consecutive sessions. Differences in pre, intradialytic, and post-HD blood pressure, interdialytic weight gain, mean serum sodium, intradialytic adverse events, and number of IDH episodes requiring intervention between the two phases were assessed. The mean age of the study population was 52 years (36 males,14 females). The mean post-HD systolic and diastolic BP was 163.26 ± 9.58 mmHg and 88.60 ± 5.27 mmHg in the standard dialysate phase and 142.38 ± 14.09 mmHg and 84.58 ± 4.276 mmHg, respectively, in the low dialysate phase (p < 0.01). Interdialytic weight gain was 3.34 ± 0.9 and 3.11 ± 0.86 in the standard and low sodium dialysate phases, respectively (p = 0.19).The mean pre-HD plasma sodium level was 138.48 ± 3.69 and 135.80 ± 1.35 mEq/dl, respectively, in standard and low dialysate phases (p = 0.01). There was significant reduction in number of IDH episodes requiring intervention. There was no difference in hypotensive episodes, adverse events between the two phases. In patients with intradialytic hypertension, low dialysate sodium significantly reduces the post-HD blood pressure and intradialytic hypertensive episodes, when compared with standard sodium dialysate.

A study of Factors Affecting Dialysis Recovery Time in Haemodialysis Patients in India.

Background:Patients on maintenance haemodialysis (MHD) often complain of fatigue and tiredness following haemodialysis sessions leading to poor compliance with the dialysis schedule. There is limited Indian data on dialysis recovery time (DRT). The present study was designed to assess the factors affecting DRT in our haemodialysis population.Methods:We recorded self-reported patient recovery times of 120 patients who satisfied the inclusion criteria, over three consecutive dialysis sessions by asking the question, 'How long does it take to recover from a dialysis session'? Data recorded included patient factors like age, sex, co-morbidities, Charlson comorbidity index score (CCI), dialysis vintage, duration of kidney disease, interdialytic weight gain (IDWG), treatment factors like ultrafiltration rate (UFR), SpKt/V, blood pump speed, dialysate sodium, session length, pre and post HD blood pressure and laboratory parameters. Health-related quality of life (HRQoL) was assessed with the KDQOL-SF v. 1.3 questionnaire. Results from the SF-36 score were summarised into the physical composite score (PCS), mental composite score (MCS) and kidney disease composite score (KDCS).Results:The mean age of the study population was 50.6 ± 12.6 years. Among the 120 patients, 77 (64.2%) were males. Thirty-nine patients (32.5%) were diabetic and 95 (79.1%) patients were hypertensive. The mean dialysis vintage of the study population was 26.1 ± 18.6 months, 41 (34.2%) patients reported DRT <2 h; 48 (40%) reported DRT between 2–6 h and 31 (25.8%) reported DRT >6 h. On multivariate regression analysis, higher IDWG, CCI score and UFR were associated with prolonged DRT. Reported DRT also inversely correlated with PCS (r = - 0.66), MCS (r = - 0.65) and KDCS (r = - 0.59) scores which was statistically significant.Conclusion:The present study showed that higher CCI scores, IDWG and UFR were associated with prolonged DRT in Indian haemodialysis patients and patients with longer recovery time had poor HRQoL. Interventions to reduce DRT need to be assessed in further trials in Indian MHD patients.

SAT-240 INTER-DIALYTIC WEIGHT GAIN IN HEMODIALYSIS PATIENTS - EPIDEMIOLOGY AND EVALUATION OF THE CLINICAL OUTCOMES

Inter-dialytic weight gain (IDWG) has been linked to various complications in hemodialysis (HD) patients, especially cardiovascular (CV) complications. High ultrafiltration (UF) rate in relation to dialysis time has also a similar impact in various studies. Furthermore, high IDWG has been associated with all cause and CV mortality. The IDWG is also influenced by the nutritional status of HD patients. We investigated the trends of IDWG in patients on regular HD aiming to examine: (1) trends of IDWG among patients in relation to different variables and comorbidities e.g. age, hypertension, diabetes, CV disease...etc.; (2) associations of high IDWG with frequency of hospitalization due to systemic volume overload and the need for extra dialysis sessions, and (3) the impact of high IDWG on the frequency of intra-dialytic hypotension (IDH). One hundred and twenty maintenance HD patients were enrolled in this study. All patients had been receiving HD for at least 3 months, on a 4 hour, thrice weekly basis. The data collected included; age, gender, duration on HD (in months), pre- and post-HD body weights (on 3 successive sessions), pre- and post-HD blood pressure (BP) measurements (on 3 successive sessions), the type of vascular access and the average blood flow rate, dialysis efficiency (based on average Kt/V), and the presence or absence of residual kidney function. The presence of various comorbidities has been recorded including; diabetes, hypertension, coronary artery and peripheral vascular diseases, heart failure, cerebrovascular disease, and other disorders. The estimated IDWG was calculated based on the average between pre- and post- dialysis weights that were recorded on 3 consecutive dialysis sessions. The estimated IDWG was expressed in kilograms and as a percentage of the patients’ dry weight. We considered an estimated average IDWG of 4% as a cutoff value between low and high IDWG. We defined IDH as the drop of systolic blood pressure of 20 mmHg or more during HD compared to the pre-dialysis blood pressure and/or a systolic blood pressure that is less than 90 mmHg. We have recorded that 50.0% of those younger than 55 years had IDWG ≥ 4%. On the other hand, only 31.7% of those aged 55 years or more had IDWG ≥ 4% (p=0.041). There was no significant gender difference regarding IDWG. Among those who had IDWG ≥ 4%, 81% of these patients had at least one hospital admission due to volume overload or the need for extra HD session(s). On the other hand, only 19% of those having IDWG < 4% had been admitted or got extra HD sessions (p<0.001). Of those who were admitted (over 12 months) due to volume overload; 74.1 % had IDWG ≥ 4%, while 25.9% had IDWG < 4% (p< 0.001). Regarding IDH, 87% of patients having IDWG ≥ 4% had at least one episode of IDH/week. On the other hand, only 22.5% of those with IDWG < 4% had one episode of IDH/week (p<0.001). When analyzing those who had at least one IDH episode/week; 72.9% of them had IDWG ≥ 4%, while only 27.1% had IDWG < 4% (p<0.001).View Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT) In HD patients, the frequency of hospital admission due to volume overload and the need for extra HD sessions is strongly related to the amount of IDWG (> 4% in our patients). The same stands for the frequency of IDH. Thus a control of IDWG in HD patient is of great importance, keeping in mind the importance the nutritional status of HD patients that may also impact IDWG.

Effects of Individualized Dialysate Sodium Prescription in Hemodialysis - Results from a Prospective Interventional Trial.

Introduction:Individualized dialysate sodium prescription does affect weight gain, blood pressure (BP), and intradialytic complications. A prospective interventional trial (Dialysate Individualised Sodium (DISO) trial) was conducted to study this issue in Indian patients.Methods:Forty patients on thrice-weekly maintenance hemodialysis (HD) for at least 6 weeks were enrolled. The study was performed in two different phases. In the first phase, 12 consecutive HD sessions were done with a standard dialysate sodium concentration of 140 mEq/L. In the second phase, 12 consecutive HD sessions were done with dialysate sodium concentration set to individualized value (mean of pre-HD sodium concentration multiplied by Donnan coefficient of 0.95). Differences in pre- and post-HD sodium, interdialytic weight gain (IDWG), pre- and post-HD BP, thirst scores, and intradialytic adverse events during both phases were assessed.Results:The mean age of patients was 45.65 years (24 males, 16 females). The mean serum pre-HD sodium level was 138.7 ± 1.7 meq/L in the standard phase and 138.2 ± 2.6meq/L in the individualized phase (P = 0.229). In the standard phase, the mean IDWG was 2.64 ± 1.56 kg and 2.13 ± 0.99 kg in the individualized phase (P = 0.008). The mean pre-HD systolic BP was 138 ± 18 mmHg and 134 ± 17 mmHg in the standard and individualized phases (P = 0.008). There was no difference in intradialytic symptoms, hypotensive episodes or requirement of interventions. Hypertension episodes occurred at a mean value of 2.2 and 1.2 in the standard and individualized phases, respectively (P = 0.010).Conclusion:The use of individualized dialysate sodium level is safe and results in lower IDWG, pre-HD systolic BP, and intradialytic hypertension in patients on HD.

Augmented Cardiopulmonary Baroreflex Sensitivity in Intradialytic Hypertension

IntroductionEnd-stage renal disease (ESRD) patients with a paradoxical increase in blood pressure (BP) during hemodialysis (HD), termed intradialytic hypertension (ID-HTN), are at significantly increased risk for mortality and adverse cardiovascular events. ID-HTN affects up to 15% of all HD patients, and the pathophysiologic mechanisms remain unknown. We hypothesized that ESRD patients prone to ID-HTN have heightened volume-sensitive cardiopulmonary baroreflex sensitivity (BRS) that leads to exaggerated increases in sympathetic nervous system (SNS) activation during HD.MethodsWe studied ESRD patients on maintenance HD with ID-HTN (n = 10) and without ID-HTN (controls, n = 12) on an interdialytic day, 24 to 30 hours after their last HD session. We measured continuous muscle sympathetic nerve activity (MSNA), beat-to-beat arterial BP, and electrocardiography (ECG) at baseline, and during graded lower body negative pressure (LBNP). Low-dose LBNP isolates cardiopulmonary BRS, whereas higher doses allow assessment of physiologic responses to orthostatic stress.ResultsThe ID-HTN patients had significantly higher pre- and post-HD BP, and greater interdialytic fluid weight gain compared to controls. There was a significantly greater increase in MSNA burst incidence (P = 0.044) during graded LBNP in the ID-HTN group, suggesting heightened cardiopulmonary BRS. The ID-HTN group also had a trend toward increased diastolic BP response during LBNP, and had significantly greater increases in BP during the cold pressor test.ConclusionPatients with ID-HTN have augmented cardiopulmonary BRS that may contribute to increased SNS activation and BP response during HD.

Comparison of Ambulatory Blood Pressure Patterns in Patients With Intradialytic Hypertension and Hemodialysis Controls

Background/Aims: Intradialytic hypertension (IH) patients have higher mortality risk than other hemodialysis patients and have been shown to have higher ambulatory blood pressure (BP). We hypothesized that interdialytic BP patterns would differ in IH patients and hypertensive hemodialysis controls. Methods: We consecutively screened hemodialysis patients at our university-affiliated units. Based on pre and post-HD BP measurements during the prior 2 week period, we identified IH patients and demographically matched hemodialysis controls. We measured ambulatory interdialytic BP, flow-mediated vasodilation, and intradialytic endothelin-1 (ET-1). Using linear mixed-models, we compared BP slopes during the following intervals: 1-24 hours post-dialysis, 25-44 hours post-dialysis, and 1-44 hours post-dialysis. Results: There were 25 case subjects with IH and 24 controls. Systolic BP during hours 1-44, 1-24, and 25-44 were 143.1 (16.5), 138.0 (21.2), and 150.8 (22.3) mmHg in controls. For IH subjects, they were 155.4 (14.2), 152.7 (22.8), and 156.5 (20.8) mmHg (p=0.008, 0.02, 0.4). In controls, the slopes were +0.6, +0.6, and +0.4 mmHg/hr. In IH subjects, they were +0.1, -0.3, and +0.3 mmHg/hr. The IH 1-24 hour slope differed from the IH 25-44 hour slope (p=0.001) and the control 1-24 hour slope (p=0.002). The change in ET-1 from pre to post dialysis was 0.5 (1.5) pg/mL in controls and 1.0 (2.3) pg/mL in IH patients (p=0.4). In a univariate model, there was an association with screening BP and BP slope (p=0.002 for controls and p=0.1 for IH patients). Conclusions: Interdialytic BP patterns differ in IH patients and hemodialysis controls. The elevated post dialysis blood pressure persists for many hours in IH patients contributing to the overall increased BP burden.

Is an average of routine postdialysis blood pressure a good indicator of blood pressure control and cardiovascular risk?

Hypertension is associated with left ventricular hypertrophy (LVH), a predictor of cardiovascular mortality in haemodialysis (HD) patients. The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) blood pressure (BP) targets are pre-HD <140/90 mm Hg, post-HD <130/80 mm Hg. This study aims to assess 3-month mean in-unit BP, pre- and post-HD, for correlations with left ventricular mass index (LVMI), a measure of long-term BP control. Of 648 HD patients, including those on HD >6 months, 262 had echocardiograms. Those with significant coronary artery disease, reduced ejection fraction or valvular disease were excluded, as were those without appropriate echocardiogram, leaving 100 patients. Data on BP and confounding factors for LVH were collected covering 3 months prior to echocardiogram. Mean BP pre-HD was 147/77 ± 19/13 mm Hg, and post-HD, 133/71 ± 20/11 mm Hg; <50% of patients achieved NKF targets. Mean LVMI was 203.7 ± 74 g/m(2); 88% of patients had LVH. On univariate analysis, mean pre- and post-HD systolic BP, mean arterial blood pressure (MAP) and post-HD diastolic and pulse pressure correlated with LVMI. On stepwise multiple regression analysis only post-HD MAP correlated with LVMI (p=0.000047, r=0.395). We conclude that long-term averages of in-unit post-HD BP measurements are useful in assessing BP control and cardiovascular risk, especially in the absence of routine ambulatory or home BP monitoring.

Fatores relacionados ao ganho de peso interdialítico em pacientes em hemodiálise

Studies have shown that interdialytic weight gain (IDWG) of hemodialysis (HD) patients is influenced by many factors, a high IDWG negatively affecting the blood pressure (BP) of this population. To evaluate the relation of clinical, demographic and nutritional factors and the IDWG of HD patients. Cross-sectional study of 278 HD (54% males; age=54.4 ± 14.4 years) from 6 dialysis centers in the State of Santa Catarina, Brazil. The means of percentage interdialytic weight gain (%IDWG) and BP during a four-week period were calculated. Body mass index (BMI) and the 7-point subjective global assessment (SGA) scale were used to assess nutritional status. The means were: %IDWG 4.06 ± 1.55%, pre-HD BP 140 ± 50 / 99 ± 25 mmHg, and post-HD BP 110 ± 27 / 78 ± 10 mmHg. %IDWG inversely correlated with age and BMI and directly correlated with pre-HD systolic BP and time on HD. Women and patients without diabetes mellitus had higher %IDWG. Only the younger subgroup of patients with SGA-defined malnutrition had higher %IDWG than well-nourished ones. When malnutrition was BMI-defined, higher %IDWG was found in the whole study population and in the female and younger age subgroups. 24% of the patients had increased %IDWG (> 5%) and, when compared with those with adequate %IDWG, had inadequate and higher levels of systolic BP (144 ± 21 versus 138 ± 20 mmHg, p < 0.05), were younger and had lower BMI. These results showed that %IDWG of HD patients was influenced by gender, time on dialysis, age and nutritional status, and that high %IDWG adversely affected the BP of this population.

Haemodialysis‐unresponsive blood pressure: Cardiovascular mortality predictor?

The importance of 'conventional' cardiovascular risk factors in haemodialysis (HD) patients has been questioned following evidence that pre-HD blood pressure (BP) might be inversely related to mortality in contrast to post-HD BP. To evaluate this reverse BP epidemiology in HD patients, HD-induced BP changes were compared with aortic pulse wave velocity (PWV), an independent predictor of cardiovascular mortality. Aortic PWV was evaluated in a limited care HD cohort, all of whom were asymptomatic of cardiovascular disease. Of 47 limited care patients, 45% were classified as HD responsive, with a 17% fall in mean arterial pressure compared with a 6% increase in the HD-unresponsive group. While there were no significant differences between the two groups in traditional vascular disease risk factors or interdialytic weight loss, PWV was significantly elevated in the HD-unresponsive group (12.9 +/- 2.7 compared with 10.8 +/- 2.9; P < 0.05). Furthermore, there was a positive correlation between the change in BP during HD and PWV in all subjects (r = 0.500; P < 0.001 for systolic blood pressure (SBP), a correlation that also existed for diastolic blood pressure (DBP) (P < 0.01). This study suggests that patients with HD-unresponsive BP are more likely to have vascular disease and this association between PWV and HD-induced BP changes might partly explain the apparent paradox of pre- and post-HD BP with mortality. It is proposed that a population with elevated post-HD BP is more likely to be composed of subjects with vascular disease (overt or occult), in contrast to a group with high pre-HD BP, which will be more heterogeneous.

Automatic feedback control of relative blood volume changes during hemodialysis improves blood pressure stability during and after dialysis

Automatic feedback systems have been designed to control relative blood volume changes during hemodialysis (HD) as hypovolemia plays a major role in the development of dialysis hypotension. Of these systems, one is based on the concept of blood volume tracking (BVT). BVT has been shown to improve intra-HD hemodynamic stability. We first questioned whether BVT also improves post-HD blood pressure stability in hypotension-prone patients and second, whether BVT is effective in reducing the post-HD weight as many hypotension-prone patients are overhydrated because of an inability to reach dry weight. After a 3-week period on standard HD, 12 hypotension-prone patients were treated with two consecutive BVT treatment protocols. During the first BVT period of 3 weeks, the post-HD target weight was kept identical compared with the standard HD period (BVT-constant weight; BVT-cw). During the second BVT period of 6 weeks, we gradually tried to lower the post-HD target weight (BVT-reduced weight; BVT-rw). In the last week of each period, we studied intra-HD and 24 hr post-HD blood pressure behavior by ambulatory blood pressure measurement (ABPM). Pre- and post-HD weight did not differ between standard HD and either BVT-cw or BVT-rw. Heart size on a standing pre-dialysis chest X-ray did not change significantly throughout the study. There were less episodes of dialysis hypotension during BVT compared with standard HD (both BVT periods: p<0.01). ABPM data were complete in 10 patients. During the first 16 hr post-HD, systolic blood pressure was significantly higher with BVT in comparison with standard HD (both BVT periods: p<0.05). The use of BVT in hypotension-prone patients is associated with higher systolic blood pressures for as long as 16 hr post-HD. BVT was not effective in reducing the post-HD target weight in this patient group.