A new technique for the detection of dry weight in hemodialysis patients: Estimated pulmonary capillary wedge pressure. A tissue Doppler imaging study

BACKGROUND AND OBJECTIVE

Fluid overload is an important factor of morbidity and mortality in hemodialysis patients. Today correct determination of dry weight (DW) remains an important issue of hemodialysis practice. Within this context, it is subjected to new method searching. The objective of this study was to calculate estimated pulmonary capillary wedge pressure (ePCWP) with Tissue Doppler Imaging (TDI) in hemodialysis patients and to evaluate its correlation with the other volume markers and to evaluate whether it can be a new method for detection of DW.

MATERIALS AND METHODS

Echocardiographic, hemodynamic, and biochemical volume markers of 41 hemodialysis patients were evaluated in the pre- and post-dialysis periods. Patients were divided into two groups based on ePCWP values (Group 1 ePCWP<20mmHg, Group 2 ePCWP>20mmHg).

RESULTS

In the pre-dialysis period; parameters related to volume load including ePCWP, systolic blood pressure, mean arterial pressure, pulse pressure, left atrial diameter, left atrial volume, E/é, ratio and E/V_p ratio were statistically significantly higher in Group2 compared to Group1. On the other hand, strong correlations were found between pre-dialysis ePCWP and systolic blood pressure, mean arterial pressure, pulse pressure, NT-ProBNP, left atrial diameter, E/é ratio and E/V_p ratio.

CONCLUSIONS

Strong correlations found between ePCWP which was calculated with TDI and the other volume markers both in pre-dialysis and post-dialysis periods. These findings can provide a significant contribution to routine evaluating of DW in hemodialysis patients. From this aspect, the prediction of ePCWP with TDI can be a new practical and reproducible method for the determination of DW.

A new technique for the detection of dry weight in hemodialysis patients: Estimated pulmonary capillary wedge pressure. A tissue Doppler imaging study

BACKGROUND AND OBJECTIVE

Fluid overload is an important factor of morbidity and mortality in hemodialysis patients. Today correct determination of dry weight (DW) remains an important issue of hemodialysis practice. Within this context, it is subjected to new method searching. The objective of this study was to calculate estimated pulmonary capillary wedge pressure (ePCWP) with Tissue Doppler Imaging (TDI) in hemodialysis patients and to evaluate its correlation with the other volume markers and to evaluate whether it can be a new method for detection of DW.

MATERIALS AND METHODS

Echocardiographic, hemodynamic, and biochemical volume markers of 41 hemodialysis patients were evaluated in the pre- and post-dialysis periods. Patients were divided into two groups based on ePCWP values (Group 1 ePCWP<20mmHg, Group 2 ePCWP>20mmHg).

RESULTS

In the pre-dialysis period; parameters related to volume load including ePCWP, systolic blood pressure, mean arterial pressure, pulse pressure, left atrial diameter, left atrial volume, E/é, ratio and E/Vp ratio were statistically significantly higher in Group2 compared to Group1. On the other hand, strong correlations were found between pre-dialysis ePCWP and systolic blood pressure, mean arterial pressure, pulse pressure, NT-ProBNP, left atrial diameter, E/é ratio and E/Vp ratio.

CONCLUSIONS

Strong correlations found between ePCWP which was calculated with TDI and the other volume markers both in pre-dialysis and post-dialysis periods. These findings can provide a significant contribution to routine evaluating of DW in hemodialysis patients. From this aspect, the prediction of ePCWP with TDI can be a new practical and reproducible method for the determination of DW.

Effects of beta-blocker use on volume status in hemodialysis patients

BACKGROUND

Removal and control of excess fluid with dialysis is considered critical for protection against cardiovascular sequelae. Antihypertensive agents including beta-blockers may influence hemodynamics, which may limit fluid removal during hemodialysis (HD).

METHODS

Fifty chronic HD patients underwent bioimpedance measurement before and after a midweek dialysis session. Data on volume status, blood pressure, antihypertensive medications, and bioimpedance were analyzed.

RESULTS

Patients in the high-volume status group used a significantly higher percentage of beta-blockers than patients in the low-volume status group (54.2 vs. 19.2%, respectively, p = 0.01). Multivariable regression revealed that the use of beta-blockers was independently positively associated with fluid overload (p < 0.05). Intradialytic muscle cramping occurred more often in the beta-blocker group than the control group (44.4 vs. 12.5%, respectively, p = 0.02).

CONCLUSIONS

Our results suggest that the use of beta-blockers was associated with fluid overload in HD patients, and patients being treated with them experienced more intradialytic muscle cramping during dialysis.

How should we manage adverse intradialytic blood pressure changes?

Variations in intradialytic blood pressure (BP) are a common and predictable occurrence in ESRD patients. These are caused by a decrease in blood volume provoked by ultrafiltration, lack of normal compensatory responses to fluid removal, underlying cardiac disease, and electrolyte changes that may adversely affect cardiovascular function. Intradialytic hypotension is the most frequent complication of the hemodialysis (HD) procedure and is fundamentally a consequence of an ultrafiltration rate that surpasses mechanisms activated to avert a decline in BP. Intradialytic hypertension is a less well-understood problem that has been recently associated with increased mortality. Fundamental patient characteristics and components of the HD procedure are involved in the pathophysiology of intradialytic hypotension and intradialytic hypertension. Correction of patient factors, modulation of HD prescription, and management of pharmacologic agents are the strategies to deal with adverse intradialytic BP changes.

Excessive fall of blood pressure during maintenance hemodialysis in patients with chronic renal failure is induced by vascular malfunction and imbalance of autonomic nervous activity

Acute hypotension during maintenance hemodialysis (HD) is not only a critical complication, but also an independent risk factor for mortality in patients with chronic renal failure (CRF). This study was designed to clarify the mechanisms underlying excessive fall of blood pressure during HD. Fifty-six CRF patients with HD thrice a week were divided into two groups according to the intradialytic hypotension episodes after 4 weeks of the observation period; the hypotension group, showing four or more episodes of intradialytic hypotension, and the non-hypotension group, showing three episodes of intradialytic hypotension or less. The intradialytic hypotension was defined as a fall of ≥30 mm Hg in the systolic blood pressure during HD. The brachial-ankle pulse wave velocity (ba-PWV), serum high-sensitivity (hs)-CRP, reactive oxygen species (ROS) generation, and serum malondialdehyde-modified LDL (MDA-LDL) were measured before HD. The high- frequency (HF) and low-frequency components (LF) of the heart rate variability and entropy were analyzed by the maximal entropy method. The ba-PWV, hs-CRP, ROS generation, and MDA-LDL were significantly higher in the hypotension group than in the non-hypotension group. HF, LF/HF, and entropy during HD increased significantly in the non-hypotension group, while entropy during HD decreased significantly in the hypotension group as compared with the baseline. LF/HF and entropy during HD were significantly lower in the hypotension group than in the non-hypotension group. These findings suggest that the major factors causing excessive fall of blood pressure during HD in patients with CRF might be vascular malfunction and imbalance of autonomic nervous activity.

Midodrine-induced vascular ischemia in a hemodialysis patient: a case report and literature review

Midodrine is an alpha-agonist that causes peripheral vasoconstriction, resulting in increased blood pressure. It has been reported to be safe and effective in patients with end stage renal disease (ESRD) and is widely used for hemodialysis-associated hypotension. We report a case report of midodrine-induced ischemia in a patient on hemodialysis and review the literature relating to the safety of midodrine in patients with end stage renal disease.

Serum vasopressin response in patients with intradialytic hypotension: a pilot study

BACKGROUND AND OBJECTIVES

Arginine vasopressin (AVP), an endogenous hormone with vasopressor properties, may be inadequately secreted during episodes of intradialytic hypotension (IDH).

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

To evaluate this, we performed a prospective, observational pilot study of 20 chronic hemodialysis patients assessing the baseline AVP level and trend of AVP with ultrafiltration in patients with a diagnosis of IDH compared with patients without IDH. Ten symptomatic IDH patients and 10 controls were enrolled and matched for age, gender, and dialysis vintage. AVP levels were obtained hourly throughout the dialysis session and during hypotensive episodes.

RESULTS

We observed that IDH patients experienced greater decreases in both systolic and diastolic blood pressure during the dialysis session despite equivalent ultrafiltration in both groups. AVP concentration did not increase in the IDH patients (5.0 +/- 1.8) compared with controls (6.4 +/- 6.0) (P = 0.5) despite hypotensive events.

CONCLUSIONS

This study suggests that symptomatic IDH patients are unable to mount an appropriate increase in AVP secretion in the setting of hypotension. These findings support the possibility of AVP as a mechanism driven therapy for patients with symptomatic IDH.

Can predialysis hypertension prevent intradialytic hypotension in hemodialysis patients?

BACKGROUND/AIM

Intradialytic hypotension is the most common complication associated with hemodialysis, and its cause is multifactorial. However, the relationship between hypertension and intradialytic hypotension is not clear. We investigated the influence of predialysis blood pressure and antihypertensive drugs on intradialytic hypotension.

METHODS

Risk factors for intradialytic hypotension were analyzed in 111 patients undergoing regular hemodialysis treatment and had annual echocardiography performed. The correlation between the addition of antihypertensive medications and the incidence of intradialytic hypotensive episodes was studied in 21 hypertensive patients.

RESULTS

Based on multivariate logistic regression analysis, diabetes (odds ratio OR 8.18, 95% confidence interval CI 1.47-45.5; p = 0.016), interdialytic weight gain (OR 2.45, 95% CI 1.24-4.82; p = 0.010), ejection fraction (OR 0.88, 95% CI 0.81-0.95; p = 0.001), and left ventricular volume (OR 0.97, 95% CI 0.94-0.99; p = 0.013) were determined as risk factors for intradialytic hypotension. However, there was no association between predialysis blood pressure and intradialytic hypotension. After additional antihypertensive medications, the predialysis blood pressure fell from 175/85 mm Hg to 154/78 mm Hg (p < 0.0001/p < 0.0001). The mean 24-hour interdialytic blood pressure fell from 165/87 mm Hg to 147/80 mm Hg (p < 0.0001/p = 0.006). However, the frequency of hypotensive episodes was not increased (p = 0.77).

CONCLUSIONS

Diabetes, excessive interdialytic weight gain, low ejection fraction, and low left ventricular volume are independent risk factors for intradialytic hypotension. However, no correlation was found between predialysis blood pressure values or addition of antihypertensive medications and the incidence of intradialytic hypotension. Thus, hypertension may be controlled without aggravating intradialytic hypotension in hemodialysis patients.

Adenosine A1 receptor antagonist improves intradialytic hypotension

Intradialytic hypotension is a most frequent complication of hemodialysis and may contribute to cardiovascular events and high mortality. There is a hypothesis that an increase in adenosine generation during hemodialysis may cause vasodilation and a decrease in cardiac output, which results in systemic hypotension. We studied whether this can be blocked by an adenosine A1 receptor antagonist. We investigated the effects of an A1 antagonist, FK352, injection in 30 chronic hemodialysis patients with frequent intradialytic hypotension by a prospective, multicenter, double-blind placebo-controlled study for 4 weeks after 4 weeks of the observation period. Intradialytic hypotension was defined as systolic blood pressure (SBP) less than 110 mmHg, with SBP drop of more than 30 mmHg from the predialysis level. The efficacy of FK352 was primarily assessed by the reduction rate of dialysis hypotension between the FK352 and placebo groups. Incidence of emergency treatments caused by hypotension was evaluated. FK352 (50 mg, intravenous) or an equivalent placebo was injected into the dialysis circuit 1 h after starting dialysis. Blood pressure and heart rate were monitored every 30 min during dialysis. FK352 significantly improved intradialytic hypotension (P=0.046), in that the reduction rates of intradialytic hypotension in the FK352 and placebo groups were -12.8% (Q1 (first quantile), Q3 (third quantile): -27.5, -1.7), and +8.3% (Q1, Q3: -16.6, +16.7), respectively. The frequency of discontinuation of dialysis was significantly reduced by FK352. No apparent side effects were observed from treatment with FK352. In conclusion, the A1 antagonist FK352 may offer a novel therapeutic option for chronic dialysis patients associated with intradialytic hypotension.

Discordance of influence of hypertension on mortality and cardiovascular risk in hemodialysis patients

BACKGROUND

Hemodialysis patients are at significantly increased risk for both morbidity and mortality from cardiovascular disease. However, most recent reports have indicated elevated mortality risk associated with low blood pressure, rather than high blood pressure. We added nonfatal cardiovascular events as an outcome in addition to cardiovascular and all-cause mortality to analyze the risk of hypertension.

METHODS

One hundred sixty-four patients receiving regular hemodialysis between January and December 1998 were examined and prospectively followed up until the end of 2003. The primary end point was hospital admission or death from cardiovascular disease. Secondary end points were cardiovascular and all-cause mortality.

RESULTS

During the 5-year follow-up period, 52 patients experienced cardiovascular events and 45 patients died (18 patients, from cardiovascular disease). Based on Cox analysis, high systolic blood pressure (relative risk [RR], 1.23; 95% confidence interval [CI], 1.07 to 1.43; P = 0.004) and older age were independently associated with cardiovascular events. Elevated systolic blood pressure (RR, 1.25; 95% CI, 0.99 to 1.59; P = 0.063) was a marginal predictor for cardiovascular mortality. Age, serum albumin level, malignant neoplasm, and diabetes were independent risk factors for all-cause mortality, whereas there was no association between blood pressure and all-cause mortality. The hazard ratio for cardiovascular events after adjustment for age, sex, and diabetes was lowest in patients with systolic blood pressure of 140.1 mm Hg or less and progressively increased with the increase in systolic blood pressure.

CONCLUSION

Hypertension is a potent risk factor for cardiovascular disease in hemodialysis patients, as in the general population, whereas there is no association of hypertension with mortality. Active reduction in systolic blood pressure is important to minimize the occurrence of cardiovascular events.

Addition of sertraline to other therapies to reduce dialysis-associated hypotension

Sertraline has shown promise in the treatment of dialysis-associated hypotension (DAH) in a limited number of end-stage renal disease patients. We undertook a study to evaluate the effect of adding sertraline to other therapies for patients with documented DAH. We also measured the effect of sertraline on intradialytic haemodynamics. We used the ultrasound dilution technique (HD01 monitor) to measure cardiac output (CO), central blood volume (CBV) and peripheral vascular resistance (PVR) in these patients. The study was performed in two phases. Phase 1 was a control, while the second phase consisted of treatment with sertraline (50 mg/day). Cardiac output and central blood volume were measured 30 min following the initiation of dialysis and 30 min prior to the termination of dialysis. Blood pressure (BP) was monitored during haemodynamic measurements and throughout dialysis. Eighteen patients with documented DAH completed the study. Cardiac output, CBV and PVR were no different in the sertraline phase as compared with the control phase. The declines in systolic BP, diastolic BP and mean arterial pressures from pre-haemodialysis (HD) to lowest intradialytic and pre-HD to post-HD were not significantly different for the sertraline phase versus the control phase. In conclusion, it appears that sertraline has no additive effect on intradialytic haemodynamics to improve blood pressure in patients with DAH who are under therapy (with sodium modelling, cool dialysate and midodrine).

Effect of sertraline hydrochloride on cardiac autonomic dysfunction in patients with hemodialysis-induced hypotension

BACKGROUND/AIMS

It was previously shown that sertraline hydrochloride treatment improved hemodynamic parameters of patients with dialysis induced hypotension (DIH). The aim of this study was to examine the effect of sertraline on the autonomic functions of patients with DIH.

METHODS

Ten patients with DIH, 10 hemodialysis patients without DIH and 10 healthy control subjects were included into the study. All of the patients were treated with sertraline 50 mg per day for 4 weeks. Pre-treatment and post-treatment heart rate variability (HRV) in supine and tilt position was evaluated. In order to evaluate the autonomic response to tilt position, gap values were calculated by subtracting the HRV in supine position from the HRV in tilt position.

RESULTS

Analysis of the HRV response to tilt, demonstrated a paradoxical reduction in the indices of sympathetic modulation and sympathovagal balance in the patients with DIH while there was an increase in normalized powers of low frequency components (LFNU) and low frequency to high frequency components ratio (LFP/HFP) in the patients without DIH and control group. The number of therapeutic interventions for restoration of DIH decreased significantly in the sertraline period (p < 0.001). The gap values of the patients with DIH in LFNU (sympathetic modulation) (p < 0.05) and LFP/HFP (sympathovagal balance) increased in the sertraline period (p < 0.01). The decrease in gap value of normalized powers of high frequency components (parasympathetic modulation) was pronounced in the sertraline period in the patients with DIH (p < 0.05).

CONCLUSION

The preventive effect of sertraline on DIH might be related to the improvement of regulation of autonomic response to hypovolemia.

Efficacy and safety of midodrine in the treatment of dialysis-associated hypotension

Dialysis-associated hypotension is a morbid problem in haemodialysis patients. Employment of midodrine at the start of dialysis has reduced the severity and frequency of hypotensive episodes in these patients. Through selective alpha(1)-adrenergic receptor-binding, desglymidodrine, the active metabolite of midodrine, raises blood pressure by enhancing venous and arterial tone. This medication has been demonstrated to be effective and safe in the acute and chronic treatment of haemodialysis-associated hypotension in end stage renal disease patients.

Hemodynamics in patients with intradialytic hypotension treated with cool dialysate or midodrine

Cool dialysate and midodrine have been used successfully to treat intradialytic hypotension (IDH) in the end-stage renal disease population. However, the exact mechanisms by which these interventions improve hemodynamic stability are not well known. We undertook a study to evaluate the effect of these modalities on intradialytic hemodynamics in patients with documented dialysis-associated hypotension. We used the ultrasound dilution technique to measure cardiac output (CO), central blood volume (CBV), and peripheral vascular resistance (PVR) in these patients. The study was performed in two phases. Phase 1 consisted of control (1A) and cool dialysate (1B) studies, whereas phase 2 consisted of control (2A) and midodrine (2B) studies. CO, CBV, and PVR were measured 30 minutes after the initiation of hemodialysis (HD) and 30 minutes before the termination of HD using the HD01 monitor. Blood pressure was measured pre-HD and post-HD. Fourteen patients with documented IDH completed the study. CO and CBV were significantly more preserved in the cool dialysate and midodrine phases compared with control phases. PVR increased in all phases of the study. Declines in mean arterial pressures from pre-HD to post-HD were less with cool dialysate versus control and midodrine versus control. Ultrafiltration volumes were not significantly different between phases. Cool dialysate and midodrine appear to improve intradialytic hemodynamics in patients with dialysis-associated hypotension, mainly through the preservation of CBV and CO, rather than significantly elevating PVR.

Pharmacologic options available to treat symptomatic intradialytic hypotension

Treatment of symptomatic intradialytic hypotension (IDH) is a difficult task for the practicing nephrologist. Minimizing patient factors that precipitate IDH as well as dialysis procedure-related components that lower blood pressure are the initial approaches to this problem. However, despite these maneuvers, hypotension often persists in a group of high-risk patients. Pharmacologic interventions are often used to reduce IDH. Unfortunately, many of the available therapies are marginally effective and/or poorly tolerated. A few therapies appear to be efficacious and well tolerated-carnitine, sertraline, and midodrine. This article reviews the various pharmacologic therapies used for IDH and makes recommendations for treatment of this difficult problem.