Assessment of blood pressure in hemodialysis patients

Sodium First Approach, to Reset Our Mind for Improving Management of Sodium, Water, Volume and Pressure in Hemodialysis Patients, and to Reduce Cardiovascular Burden and Improve Outcomes

New physiologic findings related to sodium homeostasis and pathophysiologic associations require a new vision for sodium, fluid and blood pressure management in dialysis-dependent chronic kidney disease patients. The traditional dry weight probing approach that has prevailed for many years must be reviewed in light of these findings and enriched by availability of new tools for monitoring and handling sodium and water imbalances. A comprehensive and integrated approach is needed to improve further cardiac health in hemodialysis (HD) patients. Adequate management of sodium, water, volume and hemodynamic control of HD patients relies on a stepwise approach: the first entails assessment and monitoring of fluid status and relies on clinical judgement supported by specific tools that are online embedded in the HD machine or devices used offline; the second consists of acting on correcting fluid imbalance mainly through dialysis prescription (treatment time, active tools embedded on HD machine) but also on guidance related to diet and thirst management; the third consist of fine tuning treatment prescription to patient responses and tolerance with the support of innovative tools such as artificial intelligence and remote pervasive health trackers. It is time to come back to sodium and water imbalance as the root cause of the problem and not to act primarily on their consequences (fluid overload, hypertension) or organ damage (heart; atherosclerosis, brain). We know the problem and have the tools to assess and manage in a more precise way sodium and fluid in HD patients. We strongly call for a sodium first approach to reduce disease burden and improve cardiac health in dialysis-dependent chronic kidney disease patients.

Dialysis unit blood pressure two hours after hemodialysis is useful for predicting home blood pressure and ambulatory blood pressure in maintenance hemodialysis patients

This study aimed to determine which BP measurement obtained in the HD unit correlated best with home BP and ambulatory BP monitoring (ABPM). We retrospectively analyzed data from 40 patients that received maintenance HD who had available home BP and ABPM data. Dialysis unit BPs were the averages of pre-, 2hr- (2 h after starting HD), and post-HD BP during a 9-month study. Home BP was defined as the average of morning and evening home BPs. Dialysis unit BP and home BP were compared over the 9-month study period. ABPM was performed once for 24 h in the absence of dialysis during the final 2 weeks of the study period and was compared to the 2-week dialysis unit BP and home BP. There was a significant difference between dialysis unit systolic blood pressure (SBP) and home SBP over the 9-month period. No significant difference was observed between the 2hr-HD SBP and home SBP. When analyzing 2 weeks of dialysis unit BP and home BP, including ABPM, SBPs were significantly different (dialysis unit BP > home BP > ABPM; P = 0.009). Consistent with the 9-month study period, no significant difference was observed between 2hr-HD SBP and home SBP (P = 0.809). The difference between 2hr-HD SBP and ambulatory SBP was not significant (P = 0.113). In conclusion, the 2hr-HD SBP might be useful for predicting home BP and ABPM in HD patients.

Effects of spironolactone on dialysis patients with refractory hypertension: a randomized controlled study

The purpose of this study was to evaluate the effects of spironolactone on dialysis patients with refractory hypertension and possible adverse effects. This was a 12-week prospective, randomized, double-blind trial of 82 patients randomly assigned to 12-week treatment with 25 mg/d spironolactone or placebo as add-on therapy. Visits were scheduled at the start of treatment and after 12 weeks. Measurements of 24-hour ambulatory blood pressure (BP) monitoring and morning BP were performed. After 12 weeks, spironolactone significantly improved refractory hypertension. Average placebo-corrected morning BP was reduced by 16.7/7.6 mm Hg. Mean 24-hour ambulatory BP was reduced by 10.9/5.8 mm Hg. In contrast, serum aldosterone levels in the spironolactone group slightly increased and serum potassium levels insignificantly increased. This study has demonstrated that spironolactone (50 mg) safely and effectively reduces BP in patients with refractory hypertension undergoing dialysis.

Non invasive evaluation of cardiac hemodynamics in end stage renal disease (ESRD)

OBJECTIVE

Volume overload is typical of haemodialysis patients; correct volume status evaluation is crucial in achieving blood pressure homeostasis, hypertension management and good treatment planning. This study evaluates the effect of acute volume depletion on ultrasonographic parameters and suggests two of them as able to predict patients volume overload.

PATIENTS AND INTERVENTION

27 patients with end stage renal disease treated with haemodialysis underwent a complete echocardiographic exam before, after 90 min and at the end of the dialysis.

MAIN OUTCOME AND RESULTS

Blood pressure levels significantly drop during the first 90 min of dialysis (139 ± 20 vs 126 ± 18; p < 0.0001), reaching a steady state with significantly lower values compared to baseline (130 ± 28; p = 0.02). LV and left atrial volume significantly decreased (baseline vs end dialysis 98 ± 32 vs 82 ± 31 p = 0.003 and 28 ± 10 vs. 21 ± 9 cc/m(2) p < 0.001). A significant reduction of systolic function (EF 61.6 % ± 9 vs 58.7 % ± 9 p = 0.04), of diastolic flow velocities (E/A 1.13 ± 0.37 vs. 0.87 ± 0.38 p < 0.001) and mitral annulus TDI tissue velocity (i.e. E' lat 10.6 ± 3 vs. 9.4 ± 3 cm/s; p 0.0001) were observed. Stroke work (SW) and LV end-diastolic diameter (LVEDd) indexed to height 2.7(LVEDdi) were able to predict volume overload: cut off values of respectively 13.5 mm/m(2.7) for LVEDdi and 173 cJ for SW were able to predict with a specificity of 100 % the presence of a volemic overload of at least 4 %.

CONCLUSIONS

Blood pressure, cardiac morphology and function are significantly modified by acute volume depletion and such variations are strictly interrelated. SW and LVEDd/height(2.7) may identify ESRD patients carrying an higher volume load.

Forty-four-hour interdialytic ambulatory blood pressure monitoring and cardiovascular risk in pediatric hemodialysis patients

Background

Children undergoing chronic hemodialysis are at risk of cardiovascular disease and often develop left ventricular hypertrophy (LVH). Twenty-four-hour ambulatory blood pressure monitoring (ABPM) is known to better predict cardiovascular morbidity than casual blood pressure (BP) measurement. Given the BP variability attributed to interdialytic fluid overload, 44-h ABPM should better delineate cardiovascular morbidity in pediatric hemodialysis patients.

Methods

In this cross-sectional study, 17 children (16.7 ± 2.9 years) on chronic hemodialysis underwent 44-h interdialytic ABPM and routine echocardiogram. Left ventricular mass index (LVMI) was calculated by height-based equation; LVH was defined as an LVMI in the ≥95th percentile for height-age and gender. Hypertension was defined by the recommendations of the Fourth Report of the National High Blood Pressure Education Program for casual measurements, and by those of the American Heart Association for ABPM.

Results

Twenty-four percentage of patients were hypertensive by casual post-dialytic systolic BP, whereas 59% were hypertensive by ABPM. Eighty-eight percentage of patients had abnormal cardiac geometry: 53% had LVH. Thirty-five percentage (6 of 17) had masked hypertension, including four with abnormal cardiac geometry, of which, three had LVH. LVMI correlated with ABPM, but not with casual measurements. Strongest correlations with an increased LVMI were with 44-h diastolic BP: at night (r = 0.53, P = 0.03) and total load (r = 0.57, P = 0.02). LVH was similarly associated with 44-h nighttime BP: systolic (P = 0.02), diastolic (P = 0.01) and mean arterial (P = 0.01).

Conclusions

Casual BP measurement underestimates hypertension in pediatric hemodialysis patients and does not correlate well with indicators of cardiovascular morbidity. In contrast, 44-h interdialytic ABPM better characterizes hypertension, with nighttime parameters most strongly predicting increased LVMI and LVH.

An educational training simulator for advanced perfusion techniques using a high-fidelity virtual patient model

The operation of cardiopulmonary bypass procedure requires an advanced skill in both physiological and mechanical knowledge. We developed a virtual patient simulator system using a numerical cardiovascular regulation model to manage perfusion crisis. This article evaluates the ability of the new simulator to prevent perfusion crisis. It combined short-term baroreflex regulation of venous capacity, vascular resistance, heart rate, time-varying elastance of the heart, and plasma-refilling with a simple lumped parameter model of the cardiovascular system. The combination of parameters related to baroreflex regulation was calculated using clinical hemodynamic data. We examined the effect of differences in autonomous-nerve control parameter settings on changes in blood volume and hemodynamic parameters and determined the influence of the model on operation of the control arterial line flow and blood volume during the initiation and weaning from cardiopulmonary bypass. Typical blood pressure (BP) changes (hypertension, stable, and hypotension) were reproducible using a combination of four control parameters that can be estimated from changes in patient physiology, BP, and blood volume. This simulation model is a useful educational tool to learn the recognition and management skills of extracorporeal circulation. Identification method for control parameter can be applied for diagnosis of heart failure.

Relationship between the course of depression symptoms and the left ventricular mass index and left ventricular filling pressure in chronic haemodialysis patients

AIM

Multiple measurements of depression symptoms over time were more predictive of cardiovascular mortality than a single time measurement performed at baseline. The aim of this study is to evaluate the association of the course of depression symptoms, based on repeated assessments of depression symptoms over time, with left ventricular mass index (LVMI) and left ventricular filling pressure (LVFP) in patients on haemodialysis (HD).

METHODS

The level of depression symptoms in 61 patients on HD were prospectively assessed using the Beck Depression Inventory (BDI) at baseline and at three intervals (5, 10, 15 months). Doppler echocardiographic examinations were performed at the end of follow up.

RESULTS

At the end of follow up, the patients were divided into three groups according to their course of depression symptoms: non-depression (n = 21), intermittent depression (n = 23) and persistent depression (n = 17). LVMI and LVFP were significantly increased in the persistent depression symptoms group compared to those of the non-depression symptoms group and the intermittent depression symptoms group. Persistent depression symptoms were independently associated with LVMI (β-coefficient = 0.347, P = 0.017) and LVFP (β-coefficient = 0.274, P = 0.048) after adjustment for age, sex, systolic blood pressure, diastolic blood pressure, diabetes and interdialytic weight gain.

CONCLUSION

In our study, persistent depression symptoms were associated with left ventricular hypertrophy and diastolic dysfunction. Our data may provide a more complete understanding of cardiovascular risk associated with depression symptoms in patients on HD.

Abdominal obesity is the most significant metabolic syndrome component predictive of cardiovascular events in chronic hemodialysis patients

BACKGROUND

Five components of metabolic syndrome (MetS) have been identified as predictive of cardiovascular events (CVEs) in the general population: impaired fasting glucose, abdominal obesity, hypertriglyceridemia, hypertension and low high-density lipoprotein cholesterol. Whether MetS and its components are also predictive of CVEs in chronic hemodialysis (HD) patients remains unclear. We therefore investigated the role of MetS and its components in patients on chronic HD.

METHODS

MetS at baseline was diagnosed in 91 HD patients based on the American Heart Association/National Heart, Lung and Blood Institute (AHA/NHLBI) and the International Diabetes Federation (IDF) definitions. During a 3-year period, all hospitalizations, CVEs and deaths were recorded and analyzed using Kaplan-Meier survival analysis and Cox regression.

RESULTS

There were no differences in the number of CVEs, hospitalizations or deaths between patients with and without AHA/NHLBI-defined MetS; however, patients with IDF-defined MetS were found to be at a higher risk for CVEs (P = 0.006). Cox regression analysis showed that, of the MetS components, abdominal obesity was the single most significant predictor of CVEs (hazard ratio 6.25; 95% confidence interval: 1.65-23.6; P = 0.007).

CONCLUSIONS

IDF-defined MetS was more predictive of CVEs than AHA/NHLBI-defined MetS. Of the MetS components, abdominal obesity was the single most significant predictor of CVEs in chronic HD patients.

Interdialytic hypertension-an update

The reference standard for diagnosing hypertension among hemodialysis patients is 44-hour interdialytic ambulatory blood pressure (BP) recording. However, a more practical way to diagnose and manage hypertension is to measure home BP over the interdialytic interval. In contrast to pre- and postdialysis BP recordings, measurements of BP performed outside the dialysis unit correlate with the presence of left ventricular hypertrophy and directly and strongly with all-cause mortality. Hypervolemia that is not clinically obvious is the most common treatable cause of hypertension among patients with end-stage renal disease; thus, volume control should be the initial therapy to treat hypertension in most hemodialysis patients. To diagnose hypervolemia, continuous blood volume monitoring is emerging as an effective and simple technique. Reducing dietary and dialysate sodium is an often overlooked strategy to improve BP control. Although definitive randomized trials that show cardiovascular benefits of BP lowering among hypertensive hemodialysis have not been performed, emerging evidence suggests that lowering BP might reduce cardiovascular events. The treatment should be guided by BP obtained outside the dialysis unit because predialysis and postdialysis BP are quite variable and agree poorly with measurements obtained outside the dialysis unit. Although the appropriate level to which BP should be lowered remains elusive, current data suggest that interdialytic ambulatory systolic BP should be lowered to <130 mm Hg and averaged home systolic BP to <140 mm Hg. Antihypertensive drugs will be required by most patients receiving thrice weekly dialysis for 4 hours. Beta blockers, dihydropyridine calcium blockers, and agents that block the renin-angiotensin system appear to be effective in lowering BP in these patients.

Association between routine and standardized blood pressure measurements and left ventricular hypertrophy among patients on hemodialysis

BACKGROUND

Left ventricular (LV) hypertrophy is common among patients on hemodialysis. While a relationship between blood pressure (BP) and LV hypertrophy has been established, it is unclear which BP measurement method is the strongest correlate of LV hypertrophy. We sought to determine agreement between various blood pressure measurement methods, as well as identify which method was the strongest correlate of LV hypertrophy among patients on hemodialysis.

METHODS

This was a post-hoc analysis of data from a randomized controlled trial. We evaluated the agreement between seven BP measurement methods: standardized measurement at baseline; single pre- and post-dialysis, as well as mean intra-dialytic measurement at baseline; and cumulative pre-, intra- and post-dialysis readings (an average of 12 monthly readings based on a single day per month). Agreement was assessed using Lin's concordance correlation coefficient (CCC) and the Bland Altman method. Association between BP measurement method and LV hypertrophy on baseline cardiac MRI was determined using receiver operating characteristic curves and area under the curve (AUC).

RESULTS

Agreement between BP measurement methods in the 39 patients on hemodialysis varied considerably, from a CCC of 0.35 to 0.94, with overlapping 95% confidence intervals. Pre-dialysis measurements were the weakest predictors of LV hypertrophy while standardized, post- and inter-dialytic measurements had similar and strong (AUC 0.79 to 0.80) predictive power for LV hypertrophy.

CONCLUSIONS

A single standardized BP has strong predictive power for LV hypertrophy and performs just as well as more resource intensive cumulative measurements, whereas pre-dialysis blood pressure measurements have the weakest predictive power for LV hypertrophy. Current guidelines, which recommend using pre-dialysis measurements, should be revisited to confirm these results.

Median intradialytic blood pressure can track changes evoked by probing dry-weight

BACKGROUND

Median BP obtained over a single dialysis treatment can diagnose hypertension among hemodialysis patients. Whether median BP is as useful to track change in BP is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Among patients participating in the dry-weight reduction in hypertensive hemodialysis patients (DRIP) trial, interdialytic ambulatory BP was recorded at baseline, 4 weeks, and 8 weeks. The mean interdialytic ambulatory BP was compared to the following recordings: predialysis on one dialysis treatment (Pre1), predialysis averaged over 2 weeks of dialysis treatment (Pre6), postdialysis on one dialysis treatment (Post1), postdialysis averaged over 2 weeks of dialysis treatment (Post6), and median intradialytic BP over one treatment.

RESULTS

Pre1 was unable to detect change in ambulatory BP. Although Pre6 was able to detect change, it overestimated the ambulatory BP. On average, the magnitude of reduction in Post1 in response to probing dry-weight was nearly twice that obtained by ambulatory BP monitoring. Even Post6 overestimated the magnitude of reduction in BP at 8 weeks. Median systolic BP was responsive to probing dry-weight and neither overestimated nor underestimated the interdialytic ambulatory systolic BP at baseline or over time. However, the SD of the differences between median systolic BP and interdialytic ambulatory systolic BP varied from 16 to 20 mmHg.

CONCLUSIONS

Median intradialytic BP recordings can detect change in ambulatory BP evoked by reduction in dry-weight at the population level. Because of wide agreement limits between intradialytic and interdialytic BP, the individual prediction of ambulatory BP from median intradialytic BP can be misleading.

Guided optimization of fluid status in haemodialysis patients

BACKGROUND

Achieving normohydration remains a non-trivial issue in haemodialysis therapy. Guiding the haemodialysis patient on the path between fluid overload and dehydration should be the clinical target, although it can be difficult to achieve this target in practice. Objective and clinically applicable methods for the determination of the normohydration status on an individual basis are needed to help in the identification of an appropriate target weight.

METHODS

The aim of this prospective trial was to guide the patient population of a complete dialysis centre towards normohydration over the course of approximately 1 year. Fluid status was assessed frequently (at least monthly) in haemodialysis patients (n = 52) with the body composition monitor (BCM), which is based on whole body bioimpedance spectroscopy. The BCM provides the clinician with an objective target for normohydration. The patient population was divided into three groups: the hyperhydrated group (relative fluid overload >15% of extracellular water (ECW); n = 13; Group A), the adverse event group (patients with more than two adverse events in the last 4 weeks; n = 12; Group B) and the remaining patients (n = 27; Group C).

RESULTS

In the hyperhydrated group (Group A), fluid overload was reduced by 2.0 L (P < 0.001) without increasing the occurrence of intradialytic adverse events. This resulted in a reduction in systolic blood pressure of 25 mmHg (P = 0.012). Additionally, a 35% reduction in antihypertensive medication (P = 0.031) was achieved. In the adverse event group (Group B), the fluid status was increased by 1.3 L (P = 0.004) resulting in a 73% reduction in intradialytic adverse events (P < 0.001) without significantly increasing the blood pressure.

CONCLUSION

The BCM provides an objective assessment of normohydration that is clinically applicable. Guiding the patients towards this target of normohydration leads to better control of hypertension in hyperhydrated patients, less intradialytic adverse events and improved cardiac function.

The mortality risk of overhydration in haemodialysis patients

BACKGROUND

While cardiovascular events remain the primary form of mortality in haemodialysis (HD) patients, few centres are aware of the impact of the hydration status (HS). The aim of this study was to investigate how the magnitude of the prevailing overhydration influences long-term survival.

METHODS

We measured the hydration status in 269 prevalent HD patients (28% diabetics, dialysis vintage = 41.2 +/- 70 months) in three European centres with a body composition monitor (BCM) that enables quantitative assessment of hydration status and body composition. The survival of these patients was ascertained after a follow-up period of 3.5 years. The cut off threshold for the definition of hyperhydration was set to 15% relative to the extracellular water (ECW), which represents an excess of ECW of approximately 2.5 l. Cox-proportional hazard models were used to compare survival according to the baseline hydration status for a set of demographic data, comorbid conditions and other predictors.

RESULTS

The median hydration state (HS) before the HD treatment (DeltaHSpre) for all patients was 8.6 +/- 8.9%. The unadjusted gross annual mortality of all patients was 8.5%. The hyperhydrated subgroup (n = 58) presented DeltaHSpre = 19.9 +/- 5.3% and a gross mortality of 14.7%. The Cox adjusted hazard ratios (HRs) revealed that age (HRage = 1.05, 1/year; P < 0.001), systolic blood pressure (BPsys) (HRBPsys = 0.986 1/mmHg; P = 0.014), diabetes (HRDia = 2.766; P < 0.001), peripheral vascular disease (PVD) (HRPVD = 1.68; P = 0.045) and relative hydration status (DeltaHSpre) (HRDeltaHSpre = 2.102 P = 0.003) were the only significant predictors of mortality in our patient population.

CONCLUSION

The results of our study indicate that the hydration state is an important and independent predictor of mortality in chronic HD patients secondary only to the presence of diabetes. We believe that it is essential to measure the hydration status objectively and quantitatively in order to obtain a more clearly defined assessment of the prognosis of haemodialysis patients.

Home blood pressure measurements for managing hypertension in hemodialysis patients

Home blood pressure (BP) monitoring serves as a practical method to detect changes in BP instead of ambulatory BP monitoring in hemodialysis patients. To evaluate the relationship of reduction in home BP compared to interdialytic ambulatory BP measurements we analyzed the data from the dry-weight reduction in hypertensive hemodialysis patients (DRIP) trial in which 100 patients had their dry weight probed based on clinical sign and symptoms and 50 patients served as controls. We measured home BP 3 times a day for 1 week using a validated oscillometric monitor on 3 occasions at 4-week intervals after randomization. Changes from baseline in home, predialysis BP and postdialysis BP were compared to interdialytic 44-hour ambulatory BP. Home and ambulatory BP monitoring was available in 141 of 150 (94%) patients. Predialysis systolic BP was not as sensitive as ambulatory BP in detecting change in BP with dry-weight reduction. Whereas postdialysis BP was capable of detecting an improvement in systolic BP in response to probing dry weight, by itself it does not provide evidence that change in postdialysis BP persists over the interdialytic period. Home BP reliably detected changes in ambulatory BP, albeit with less sensitivity at 4 weeks. However, at 4 and at 8 weeks, changes in home systolic BP were most strongly related to changes in interdialytic ambulatory systolic BP compared to predialysis and postdialysis BP. The reproducibility of BP measurements followed the order home > ambulatory >> predialysis > postdialysis. These data provide support for the use of home BP monitoring for the management of hypertension in hemodialysis patients.

Dry-weight reduction in hypertensive hemodialysis patients (DRIP): a randomized, controlled trial

Volume excess is thought to be important in the pathogenesis of hypertension among hemodialysis patients. To determine whether additional volume reduction will result in improvement in blood pressure (BP) among hypertensive patients on hemodialysis and to evaluate the time course of this response, we randomly assigned long-term hypertensive hemodialysis patients to ultrafiltration or control groups. The additional ultrafiltration group (n=100) had the dry weight probed without increasing time or duration of dialysis, whereas the control group (n=50) only had physician visits. The primary outcome was change in systolic interdialytic ambulatory BP. Postdialysis weight was reduced by 0.9 kg at 4 weeks and resulted in -6.9 mm Hg (95% CI: -12.4 to -1.3 mm Hg; P=0.016) change in systolic BP and -3.1 mm Hg (95% CI: -6.2 to -0.02 mm Hg; P=0.048) change in diastolic BP. At 8 weeks, dry weight was reduced 1 kg, systolic BP changed -6.6 mm Hg (95% CI: -12.2 to -1.0 mm Hg; P=0.021), and diastolic BP changed -3.3 mm Hg (95% CI: -6.4 to -0.2 mm Hg; P=0.037) from baseline. The Mantel-Hanzel combined odds ratio for systolic BP reduction of > or =10 mm Hg was 2.24 (95% CI: 1.32 to 3.81; P=0.003). There was no deterioration seen in any domain of the kidney disease quality of life health survey despite an increase in intradialytic signs and symptoms of hypotension. The reduction of dry weight is a simple, efficacious, and well-tolerated maneuver to improve BP control in hypertensive hemodialysis patients. Long-term control of BP will depend on continued assessment and maintenance of dry weight.

Diagnosing hypertension by intradialytic blood pressure recordings

BACKGROUND AND OBJECTIVES

The diagnosis of hypertension among hemodialysis patients by predialysis or postdialysis blood pressure (BP) recordings is imprecise and biased and has poor test-retest reliability. The use of intradialytic BP measurements to diagnose hypertension is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A diagnostic-test study was done with interdialytic ambulatory BP as reference standard. Index BP recordings tested were: predialysis (method 1), postdialysis (method 2), intradialytic (method 3), intradialytic including predialyis and postdialysis (method 4), and the average of predialysis and postdialysis (method 5). Each index BP was recorded over six consecutive dialysis treatments.

RESULTS

There were differences among index BP measurements in reproducibility, bias, precision, and accuracy. Method 4 was the most reproducible (intraclass correlation coefficient = 0.70 for systolic and diastolic BP). All 5 measurement methods overestimated 44-h ambulatory systolic BP. Methods 2, 3, or 4 overestimated ambulatory systolic BP by only a small amount. Method 4 was the most precise and accurate. For diagnosis of hypertension, BP cut-point by method 4 of 135/75 mmHg, had a sensitivity of 90.4% and specificity of 75.9% for systolic BP (area under ROC curve 0.90). Median cut-off systolic BP of 140 mmHg from a single dialysis provides approximately 80% sensitivity and 80% specificity in diagnosing systolic hypertension; a median cut-off diastolic BP of 80 mmHg provides approximately 75% sensitivity and 75% specificity in diagnosing diastolic hypertension.

CONCLUSIONS

Consideration of intradialytic BP measurements together with predialysis and postdialysis BP measurements improves the reproducibility, bias, precision, and accuracy of BP measurement compared with predialysis or postdialysis measurements.

The association between blood pressure and mortality in ESRD-not different from the general population?

Hypertension (HTN) is a traditional cardiovascular risk factor and is prevalent in end-stage renal disease (ESRD). There are no adequately powered prospective studies that explore the natural history and outcomes of HTN and blood pressure management in ESRD. Observational studies have not uniformly showed a relationship between HTN and mortality risk in this population. Furthermore, many studies paradoxically show an increased risk of death associated with low and "normal" blood pressure (BP), sometimes referred to as "reverse epidemiology." We review findings from observational studies specifically performed in ESRD and provide an alternative interpretation-that patients with kidney disease on dialysis therapy are indeed different from the general population. At minimum, these differences may be based on the prevalence of cardiovascular morbidity, specifically the excessive prevalence of congestive heart failure. However, there are other reasons for ESRD patients, especially those on hemodialysis, to exhibit differential effects with regard to blood pressure and outcomes. We explore the implications of available observational evidence and recommend studies that elucidate the differences between ESRD and the general population. Because of the higher mortality risk associated with low or "normal" BP, diagnostic and therapeutic options and strategies for ESRD patients whose BP falls within "goal" should be addressed in future iterations of clinical practice guidelines. These strategies may include assessment of cardiac function and careful attention to achieving optimal fluid balance.

Home blood pressures are of greater prognostic value than hemodialysis unit recordings

BACKGROUND AND OBJECTIVES

Although ambulatory BP recordings are found to be superior to dialysis unit recordings in predicting outcomes, ambulatory BP are difficult to obtain in the day-to-day treatment of hemodialysis patients. Home BP agree well with ambulatory BP, but the prognostic significance of home BP recordings is unknown in hemodialysis patients. This study ascertained the role of home BP in predicting all-cause and cardiovascular mortality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A prospective cohort study was conducted in 150 patients who were on chronic hemodialysis dialyzing at four university-affiliated units. BP was self-measured at home for 1 wk, for an interdialytic interval by ambulatory recording, and by "routine" and standardized methods in the dialysis unit for 2 wk. Patients were followed for a median of 24 mo to assess the end points of all-cause and cardiovascular mortality.

RESULTS

Cardiovascular death occurred in 26 (17%) patients and death in 46 (31%) patients. A 1-SD increase in systolic BP increased the risk for death by 1.35 (95% CI 0.99 to 1.84) and in diastolic BP by 1.40 (95% CI 1.03 to 1.93) for home BP and between 0.97 to 1.19 (P > 0.20) for all-cause mortality for dialysis unit BP recording. A dose-response relationship between increasing quartiles of home BP and all-cause mortality and cardiovascular mortality was seen.

CONCLUSIONS

Self-measured systolic BP of 125 to 145 mmHg and of 115 to 125 mmHg by ambulatory BP is associated with the best prognosis in hemodialysis patients.

Impact of hemocontrol on hypertension, nursing interventions, and quality of life: a randomized, controlled trial

BACKGROUND

Volume overload contributes to the pathogenesis of hypertension in hemodialysis (HD) patients.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

The Hemocontrol (HC) system (Gambro), which automatically adjusts ultrafiltration rate and dialysate conductivity during dialysis, has been suggested to improve hemodynamic tolerance and thereby facilitate fluid removal. A 6-mo randomized, controlled trial was performed to test the hypothesis that the addition of the HC system to a systematic BP management protocol may lower home BP in comparison with standard HD as primary end point. Secondary end points were the number of nursing interventions during dialysis and health-related quality of life.

RESULTS

Complete BP data were available for 36 of the 44 patients who completed the trial. There was a statistically significant overall decrease in systolic BP during the study period (P = 0.005). However, the difference between the HC group and the standard HD group was NS (HC: from 147.8 +/- 21.7 to 139.8 +/- 16.2 mmHg; standard HD: from 141.9 +/- 19.2 to 135.2 +/- 9.9 mmHg). The number of HD sessions that required nursing interventions decreased in the HC group, whereas it increased in the standard HD group (HC: 42.9% reduction; standard HD: 35.7% increase; P = 0.04). There was also a significant improvement in health-related quality of life in the HC group but not in the standard HD group.

CONCLUSIONS

These results suggest that the addition of the HC system to a systematic BP management protocol provides no additional benefit with regard to BP reduction. However, the HC system may improve the patient tolerability to dialysis.

Appropriateness of antihypertensive drug therapy in hemodialysis patients

The prevalence and treatment of hypertension in hemodialysis (HD) patients exceeds 85% in the United States. Because of uncertainties in the evaluation of BP, it is unclear whether the HD patients who are being treated with medications are truly hypertensive. For ascertainment of the appropriateness of antihypertensive therapy, a prospective study in which antihypertensive drugs were discontinued in HD patients and 44-h interdialytic ambulatory BP monitoring was performed and left ventricular mass and inferior vena cava were measured by echocardiography was conducted. Home BP was monitored weekly during washout. An average of 2.3 medications were tapered and discontinued in 41 black participants (age 56 yr, 46% men, 54% diabetes, duration of dialysis 5.3 yr). Thirty-three (80%) of 41 patients became hypertensive, but eight (20%) remained normotensive at 3 to 5 wk. Patients who remained normotensive had a higher body mass index (31 versus 25.7 kg/m2) and diabetes (78 versus 45%), were less likely to smoke (13 versus 52%), had lower home BP at baseline (135/76 versus 147/85 mmHg), and had a lower left ventricular mass index (115 versus 146 g/m2). The rate of rise of home BP was more rapid in patients who became hypertensive. None of the normotensive patients were volume overloaded in contrast to 12% of the hypertensive patients. It is concluded that a majority of the treated black hypertensive patients are appropriately receiving therapy for hypertension. Those who have well-controlled home BP and no left ventricular hypertrophy may have a cautious withdrawal of their antihypertensive drugs.

Home blood pressure monitoring improves the diagnosis of hypertension in hemodialysis patients

Using interdialytic ambulatory blood pressure (BP) recordings as the reference standard, we compared the performance of routine, standardized and home BP monitoring in 104 predominantly black patients on chronic hemodialysis for at least 3 months. Dialysis unit BP recordings were averaged over 2 weeks and home BP over 1 week. Awake ambulatory BP of > or =135 mmHg systolic or > or =85 mmHg diastolic was taken as evidence of hypertension. Average awake ambulatory BP was 128.1+/-21.6/73.5+/-13.5 mmHg, home BP 141.3+/-21.9/78.7+/-11.9 mmHg, standardized pre-dialysis BP 141.7+/-22.6/74.2+/-13.5 mmHg and post-dialysis 119.9+/-20.5/69.1+/-13.1 mmHg, routine pre-dialysis 145.4+/-21.8/79.0+/-13.1 mmHg and post-dialysis 131.5+/-19.2/72.5+/-11.4 mmHg. Sixty-three percent of the patients had well-controlled BP by ambulatory BP monitoring and isolated diastolic hypertension was rare (3%). The standard deviation of the differences between ambulatory and routine pre-dialysis BP was 17.6 mmHg, routine post-dialysis was 16.1 mmHg, standardized pre-dialysis was 16.4 mmHg, standardized post-dialysis was 14.1 mmHg, and home BP was 14.2 mmHg. The area under receiver operating characteristic curves was similar for home and standardized BP but lower for routine BP. Home systolic BP of > or =150 mmHg averaged over 1 week had the best combination of sensitivity (80%) and specificity (84.1%) in diagnosing systolic hypertension--present in 94% of the hypertensive dialysis patients. Home BP monitoring is similar to standardized recording of BP in hemodialysis patients. A systolic BP threshold of 150 mmHg at home averaged over 1 week serves as a useful predictor of hypertension diagnosed by ambulatory BP monitoring.

Accuracy of oscillometric blood pressure monitoring with concurrent auscultatory blood pressure in hemodialysis patients

BACKGROUND

Oscillometric devices are commonly used to measure blood pressure and their validation entails sequential measurements of auscultated and oscillometric blood pressures. It is unknown whether simultaneous measurement of auscultated blood pressure and concurrent digitization and recording of the sounds can improve assessment of such devices. The aim of this study was to develop a technique of simultaneous measurement of blood pressure using oscillometric and auscultated measurements in the same deflation. Using such a device, we validated the Omron HEM-907 blood pressure measuring device in hemodialysis patients.

METHODS

Twenty non-hypertensive subjects and 20 hemodialysis patients were studied. Six blood pressure readings were obtained in each participant; three readings were obtained using the automatic, oscillometric mode of Omron HEM-907 and three readings were obtained using the manual mode of the Omron HEM-907. In each situation, simultaneous digitized Korotkoff sounds and manometric pressures were recorded. The grading scale indicated by the British Hypertension Society protocol was used to assess the device.

RESULTS

Systolic blood pressure measured simultaneously by digitized sound and pressures agreed closely for systolic pressure (Grade A for both hemodialysis and normal controls) but not for diastolic pressure (Grade C for both hemodialysis and controls). Sequential comparison of oscillometric readings with auscultated systolic and diastolic pressure yielded a Grade B for both hemodialysis patients and controls. When concurrent digitized systolic readings were used, however, Grade A was achieved for both populations for systolic readings, but Grade C for diastolic readings. The mean differences (SD) between the oscillometric and auscultatory blood pressure reading in normal controls were 4.3 (8.9) and 0.6 (8.7) for systolic and diastolic blood pressures, respectively. In hemodialysis patients, the mean differences (SD) were 2.7 (9.3) and 0.4 (7.0) for systolic and diastolic blood pressures, respectively.

CONCLUSION

Simultaneous measurement of digitized Korotkoff sounds and pressure can improve the assessment of devices for systolic but not diastolic blood pressure. The Omron HEM-907 device can be recommended for use in hemodialysis patients.

Out-of-hemodialysis-unit blood pressure is a superior determinant of left ventricular hypertrophy

Blood pressures (BPs) obtained in the dialysis unit correlate poorly with ambulatory BP and left-ventricular hypertrophy (LVH). We compared the performance of BP obtained within and outside the dialysis unit as a correlate of LVH. BP was obtained in the dialysis unit using routine and standardized methods and outside the dialysis unit using home and ambulatory BP monitoring in 140 patients (mean age, 56 years; 89 men; 129 blacks; and 59 with diabetes mellitus) on chronic hemodialysis for > or =3 months. Dialysis unit BP recordings were averaged over 2 weeks, and home BP averaged over 1 week. Ambulatory BP monitoring was performed during an interdialytic interval. Echocardiography was performed immediately after dialysis for the assessment of left-ventricular mass. Left ventricular mass/height(2.7) of >51 g/m2 was taken as evidence of LVH. Test performance of various BPs was compared using receiver operating characteristic curves. Average ambulatory BP was 129.7+/-21.2/73.6+/-13.1 mm Hg, home BP was 139.4+/-21.2/79.0+/-12.5 mm Hg, standardized predialysis BP was 142.1+/-21.7/74.9+/-13.3 mm Hg, postdialysis was 120.9+/-20.8/69.6+/-12.5 mm Hg, routine predialysis was 145.6+/-20.7/79.4+/-13.1 mm Hg, and postdialysis was 132.0+/-19.3/72.6+/-11.1 mm Hg. Left ventricular mass/height(2.7) was 59.1+/-16.5, and 68% had LV hypertrophy. Diastolic BP measured by any technique was not associated with LVH. Routine and standardized measurements of BP were similarly weak correlates of LVH. Systolic BP outside the dialysis unit was a stronger correlate of LVH compared with dialysis unit BP.

Hypertension in Chronic Kidney Disease and Dialysis: Pathophysiology and Management

Hypertension affects 24% of the adult US population. In the United States, 3% of the adult population has an elevated serum creatinine level, and 70% of these patients have hypertension. The prevalence of hypertension in chronic kidney disease (CKD) depends on the patient's age and the severity of renal failure, proteinuria, and underlying renal disease. As patients with CKD progress to end-stage renal disease (ESRD), 86% are diagnosed with hypertension. It has long been recognized that kidney function affects and is affected by hypertension. This article discusses the pathophysiology and management of hypertension in patients with CKD.

Effect of exercise training on interdialytic ambulatory and treatment-related blood pressure in hemodialysis patients

BACKGROUND

Exercise training improves blood pressure (BP) in the general population, but prior studies in hemodialysis (HD) patients only used pill counts or treatment-related BPs. We evaluated the effect of 3 to 6 months of intradialytic exercise training on ambulatory blood pressure (ABP) and treatment-related pre- and postdialysis BP.

PATIENTS AND METHODS

Nineteen chronic HD patients trained with an exercise bicycle for 30 to 60 min in the first 1 to 2 hr of each of thrice weekly HD. Interdialytic 44-hr ABP was performed a week before training began and repeated at 3 and 6 months. Pre- and post-HD systolic and diastolic BP and pre- and post-HD weight were recorded for 2 months prior to training, throughout the training, and, if available, for the 2 months after training ended. BP medications were recorded throughout. Body composition by bioimpedance, and norepinephrine and epinephrine levels by RIA were done at 0, 3, and 6 months.

RESULTS

Thirteen subjects who completed at least 3 months of training exercised 90% of HD sessions for 56 min +/- 23 SD each. Systolic and diastolic 44-hr interdialytic ABP fell during training (systolic 138.4 mmHg +/- 19.6 vs. 125.7 mmHg +/- 20.0 vs. 125.9 mmHg +/- 22.9; diastolic 83.2 mmHg +/- 10.2 vs. 74.7 mmHg +/- 9.0 vs. 73.9 mmHg +/- 11.8 at 0, 3, and 6 months; p < .05 ANOVA). Norepinephrine and epinephrine levels did not independently predict systolic BP. Pre-HD systolic BP was stable during the pretraining period, fell significantly during the training period (p < .03), and returned toward preexercise levels during the posttraining period (p < .001). Pre- or postweight, erythropoietin dose, total body water, and number of BP meds were unchanged.

CONCLUSION

Exercise training during HD significantly improves both interdialytic ABP and treatment-related BP.

Recent insights from studies using ambulatory blood pressure monitoring in patients with renal disease

PURPOSE OF REVIEW

To identify and evaluate recent (2000-2003) published studies employing ambulatory blood pressure monitoring in patients with chronic renal failure, on dialysis, and after renal transplantation.

RECENT FINDINGS

We discuss several studies that have employed ambulatory blood pressure monitoring to refine the analysis of the link between blood pressure levels, and diurnal alterations, and end-organ damage or patient survival. There is now some evidence that an abnormal diurnal blood pressure profile, although intrinsically not a very reproducible label, has predictive value for patient survival, and that the non-dipping phenomenon is linked to a high incidence of cardiovascular disease and autonomic dysfunction.

SUMMARY

Ambulatory blood pressure monitoring remains an important adjunct to the comprehensive cardiovascular evaluation of patients with chronic, end-stage renal failure or after renal transplantation.

Hypertension in dialysis

PURPOSE OF REVIEW

Hypertension is highly prevalent in dialysis patients and may be important to the high cardiovascular mortality of this population. This review shows the current direction in dialysis-associated hypertension management.

RECENT FINDINGS

Decreasing dialysate sodium concentration based on pre-hemodialysis plasma sodium concentration may have an additive effect in controlling hypertension. Sympathetic nervous system overactivity is an important feature of end-stage renal disease; a new amine oxidase, renalase, may be relevant to the pathogenesis of hypertension in this population. Similarly, drugs that block the sympathetic nervous system are uniformly protective in dialysis patients. Daily dialysis (short or long) results in better blood pressure control, and the mechanisms resulting in this effect are increasingly better understood.

SUMMARY

Long-term control of hypertension is necessary in dialysis patients. The better understanding of the dialysis-associated hypertension pathogenesis has impact on the dialysis prescription and antihypertensive drug choices.

Diurnal variation of blood pressure; reproducibility and association with left ventricular hypertrophy in hemodialysis patients

OBJECTIVE

The objective of this paper is to describe the pattern of diurnal blood pressure (BP) change in hemodialysis patients, determine the association of the non-dipping pattern of diurnal BP with left ventricular mass index (LVMI), and to determine if the nocturnal profile of BP is reproducible when repeated over time.

METHODS

In a cross-sectional study, ambulatory blood pressure monitoring (ABPM) was performed over a midweek 44-h period and echocardiography was performed on the interdialytic day. Patients with a night/day systolic and diastolic BP ratio on both days >0.9 were defined as non-dippers. Ambulatory blood pressure monitoring was repeated at 6 and 12 months follow-up.

RESULTS

Of the 59 patients, 88% were African-American, and 48% were non-dippers. Mean LVMI was significantly higher in the non-dipper (68.3+/-25 g/height) compared to the dipper patients (55.6+/-16, P<0.05). Mean nocturnal systolic BP (r=0.35) and the night/day systolic BP ratio (r=0.39) had a higher correlation with M-mode LVMI than pre-dialysis (r=0.32). After adjustment for 44-h mean SBP, night/day systolic BP ratio remained independently associated with LVMI (beta coefficient 147.62, P=0.004). Of 12 patients who had a non-dipper profile at baseline, 11 (92%) demonstrated the same profile after 6 months and 1 year of follow-up.

CONCLUSION

Many hemodialysis patients demonstrate a non-dipper profile; the degree of decline in nocturnal BP is independently associated with LVMI even after adjustment for mean BP. Patients who are identified as non-dippers consistently reproduce the same profile over time.

Blood pressure measurement in hemodialysis patients

Measurement of blood pressure (BP) poses some unique challenges in hemodialysis patients. Timing of BP measurement in relation to dialysis, changes in interdialytic weight gain, and inconsistent BP measurement technique in dialysis units contribute to the variability of BP readings in this population. This may contribute to the equivocal relationship between hypertension and cardiovascular outcomes documented in several epidemiologic studies in this population. Home BP readings are promising, but need to be validated as a measure of the burden of hypertension in this population. It is important to standardize BP measurement in all hemodialysis units according to published guidelines to improve the management of hypertension. Future research studies should carefully validate the technique used to measure BP.

Special Article: Improving Outcomes in CKD and ESRD Patients: Carrying the Torch from Training to Practice

Practicing nephrologists are spending more time caring for end-stage renal disease (ESRD) and chronic kidney disease (CKD) patients. Despite this focus, and considerable advances in the understanding of those aspects of care that impact on clinical outcomes, morbidity, mortality, and quality of life for these patients has not improved substantially over the past decade. One of the possible explanations for this lack of progress is the structure of current nephrology training programs, where ESRD and CKD patient care is not emphasized. To address this issue, we developed a short preceptorship for second-year nephrology fellows, including didactic lectures and workshops. Of 67 participating fellows, 50% were from programs offering 3 or fewer months of exposure to outpatient hemodialysis, and 25% reported no exposure to peritoneal dialysis. Of more concern, 25% reported no "official rounds" with an attending nephrologist on dialysis patients. If nephrologists are to take their appropriate place as leaders of the care delivery team, nephrology fellowships must be restructured with appropriate emphasis placed on the comprehensive care of ESRD and CKD patients.

Blood pressure measurement in dialysis patients

The best method and timing of blood pressure (BP) measurement in end-stage renal disease are subject to controversy. This issue is especially relevant in hemodialysis patients, where unique causes of inaccuracy may exist. The lack of standardization of BP measurement in the dialysis unit may lead to misdiagnosis, so close attention must be paid to technical methods to obtain BP. A composite of BP measurements over a period of 1 to 2 weeks rather than isolated readings should be used for guidance. Interdialytic BP monitoring with an ambulatory BP monitor is the most reproducible method and is thought to best represent BP in dialysis patients. If available, ambulatory BP is a useful tool to evaluate the quality of BP control in the interdialytic period. Alternative forms of BP measurement, such as home BP, 20-minute postdialysis BP, and short (3-hour to 4-hour) ambulatory blood pressure monitoring (ABPM), could prove useful when feasible or available. In this paper, we discuss the evidence regarding BP measurement in dialysis patients, new techniques under development, and recommendations for clinical practice.

Systolic hypertension in hemodialysis patients

Systolic hypertension with or without diastolic hypertension is a major problem in hemodialysis (HD) patients; isolated diastolic hypertension is uncommon. Accelerated age-related changes in vascular stiffness, together with factors peculiar to uremia, lead to loss of large and small vessel distensibility and profound changes in circulatory function that includes an increase in systolic pressure and widening of the pulse pressure. Epidemiologic studies show a direct relationship of mortality with systolic blood pressure (BP) and an inverse relationship with diastolic BP. Thus systolic BP should be the focus of treatment. In HD patients with systolic hypertension, diastolic BP is inversely related to cardiovascular risk. An accurate diagnosis of hypertension followed by nonpharmacologic measures (sodium restriction, exercise, dry weight) should be the initial steps in BP reduction. The second step should be the use of antihypertensive agents, particularly the use of angiotensin converting enzyme (ACE) inhibitors and/or beta-blockers. The use of these agents has been associated with better outcomes in observational studies in HD patients. Furthermore, the administration of atenolol and lisinopril can be supervised three times a week to achieve improved BP control. Daily dialysis may improve BP and cardiovascular risk factors. Although more difficult to implement, it may emerge as a feasible alternative to conventional dialysis. Adequate systolic BP control with these available and emerging techniques should help stem the tide of cardiovascular mortality and mortality in HD patients.