Hemodialysis-associated hypertension: pathophysiology and therapy

Hemodialysis for the non-nephrologist

Hemodialysis is now routinely provided to more than 300,000 patients in the United States. An epidemic of end-stage renal disease will nearly double this number by 2010. Patients undergoing chronic hemodialysis have high morbidity and mortality rates. Given these facts, most medical providers will be involved in the care of patients undergoing hemodialysis and it is thus important to have an understanding of the dialysis procedure and its attendant risks. This review discusses the basic physiology of the dialysis procedure and its associated complications.

Hypertension in pediatric patients on long-term dialysis: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS)

BACKGROUND

Elevated blood pressure (BP) is frequent in children on long-term dialysis therapy. However, the prevalence of hypertension and status of BP control in these patients are lacking. Using the North American Pediatric Renal Transplantation Cooperative Study database, we determined the prevalence of hypertension and assessed risk factors for elevated BP during long-term dialysis therapy in children.

METHODS

The study cohort included 3,743 patients (age, 0 to 21 years). Uncontrolled hypertension is defined as BP equal to or greater than age-, sex-, and height-specific 95th percentiles; controlled hypertension was considered in children who were administered antihypertensive medications, but had BP less than the 95th percentile.

RESULTS

A total of 76.6% of patients had either uncontrolled (56.9%) or controlled (19.7%) hypertension at baseline. Normotensive children at baseline had significant BP increases, whereas hypertensive children at baseline had significant BP decreases during the first year of dialysis therapy. BP did not change significantly after 1 year of dialysis therapy; 51% of patients had uncontrolled hypertension after 1 year of maintenance dialysis therapy. Logistic regression analysis shows that baseline hypertensive status and use of BP medications are both large significant risk factors for subsequent hypertension. Other risk factors include young age, acquired cause of renal failure, black race, initiation of dialysis therapy in 1992 to 1997, and hemodialysis as a mode of renal replacement therapy.

CONCLUSION

Hypertension is very prevalent and difficult to control in children on dialysis therapy. Results also suggest that the initial months on maintenance dialysis therapy might be the window of opportunity when careful monitoring and aggressive management of hypertension would allow achieving BP control in these patients.

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.

Newer Paradigms in Renal Replacement Therapy: Will They Alter Cardiovascular Outcomes?

Cardiovascular disease remains the leading cause of morbidity and mortality for patients with end-stage renal disease. Conventional hemodialysis has had limited impact on cardiovascular risk factors and mortality. Increasing evidence suggests that nocturnal home hemodialysis has beneficial effects on cardiovascular parameter outcomes. This article reviews the documented effects of nocturnal home hemodialysis on blood pressure control, cardiac geometry and left ventricular systolic function, lipid profiles, calcium-phosphate metabolism, parathyroid hormone levels, homocysteine levels, sleep apnea, and autonomic modulation of heart rate. It discusses possible mechanisms to explain these observed changes.

Hypertension and the Kidney

Hypertension is an important and widely prevalent risk factor for the development of chronic kidney disease (CKD), which unfortunately may progress to end-stage renal disease. CKD is a progressive condition that causes significant morbidity and mortality. Diabetes is the leading cause of end-stage renal disease in the Western world. Both hypertension and diabetes are the causative factors for the occurrence of CKD and its consequences. Aggressive control of hypertension and diabetes is indicated to reduce the risk for kidney disease in the community. Certainly, effective control of hypertension is a proven modality to prevent renal disease. The concept of decreasing the systemic blood pressure as well as the intraglomerular pressure has led to the application of rational therapeutic options in patients with renal insufficiency. Although treatment of hypertension alone is critical, drugs that block the renin-angiotensin system have been shown to have special renal (and cardiovascular) benefits. Early detection and treatment of microalbuminuria is an integral part of disease management. This article reviews the pathophysiologic and therapeutic implications of the link between hypertension and the kidney.

A systematic review of the effect of nocturnal hemodialysis on blood pressure, left ventricular hypertrophy, anemia, mineral metabolism, and health-related quality of life

BACKGROUND

Nocturnal hemodialysis is a novel form of dialysis where patients perform dialysis 6 nights per week while they sleep. Multiple publications report significant improvements in selected clinical outcomes, although the strength of these results is limited by shortcomings in study design. A systematic review of the current available literature was undertaken to examine the effect of nocturnal hemodialysis on key health outcomes.

METHODS

An inclusive search of medical databases was undertaken to identify all nocturnal hemodialysis studies. These results were manually reviewed for relevance to nocturnal hemodialysis and its impact on the following predefined health outcomes: blood pressure control, left ventricular hypertrophy, anemia, mineral metabolism, and health related quality of life. Case reports, short-term studies (<4 weeks), studies without comparator groups, and studies not reporting data in a quantitative fashion were excluded. The results of the remaining studies were reported in tabular format.

RESULTS

Of the initial 270 studies identified, only 14 met inclusion/exclusion criteria. No studies examining the impact of nocturnal hemodialysis on mortality were identified. All studies reported improved blood pressure control after conversion to nocturnal hemodialysis. Data regarding the other health outcomes of interest revealed mixed results.

CONCLUSION

Nocturnal hemodialysis is a potential alternative to conventional intermittent hemodialysis. Before significant resources are invested in initiating nocturnal hemodialysis programs, further data on mortality and cardiovascular morbidity, preferably from randomized clinical trials, are required.

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.

Blood pressure control before and after starting dialysis

BACKGROUND/AIM

We have previously reported a study on the adequacy of management of hypertension in patients developing end-stage renal failure (ESRF) over a period of 3 years from a single health district in the UK (n = 107). There were significant shortcomings in all aspects of management of hypertension including blood pressure (BP) control.

METHODS

In this report, we have compared BP control in the same cohort of patients before and after starting renal replacement therapy (RRT).

RESULTS

BP control improved significantly after the patients were established on dialysis (mean 158/ 87 mm Hg pre-RRT vs. 152/82 mm Hg post-RRT; p < 0.0001), and fewer antihypertensive agents were prescribed to control BP (mean 2.45 vs. 1.74) in this period (p < 0.0001). Moreover, patients on continuous ambulatory peritoneal dialysis (n = 50) had a better systolic BP control compared with the haemodialysis patients (n = 57; p = 0.03).

CONCLUSIONS

This study shows significant improvement in BP control in a cohort of patients with ESRF following the start of dialysis.

Drug therapy for hypertension in hemodialysis patients

The majority of end-stage renal disease (ESRD) patients are hypertensive. Drug therapy for hypertension in hemodialysis (HD) patients includes all classes of antihypertensive drugs, with the sole exception of diuretics. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers may decrease morbidity and mortality by reducing the mean arterial pressure (MAP), aortic pulse wave velocity, and aortic systolic pressure augmentation, as well as left ventricular hypertrophy (LVH) and probably reduction of C-reactive protein (CRP) and oxidant stress. Potential risk factors include hyperkalemia, anaphylactoid reaction with AN69 membranes (particularly ACE inhibitors), and aggravation of renal anemia. beta-blockers decrease not only mortality, blood pressure (BP), and ventricular arrhythmias, but also improve left ventricular function in ESRD patients. Nonselective beta-blockers can cause an increase in serum potassium (particularly during fasting or exercise). Lisinopril and atenolol have a predominant renal excretion and therefore a prolonged half life in ESRD patients. Thus thrice-weekly supervised administration of these drugs after HD can enhance BP control. The use of calcium channel blockers is also associated with lower total and cardiovascular-specific mortality in HD patients. Minoxidil is a very potent vasodilator that is generally reserved for dialysis patients with severe hypertension. Hypertensive dialysis patients who are noncompliant with their medications may benefit from transdermal clonidine therapy once a week. The majority of dialysis patients need a combination of several antihypertensive drugs for adequate BP control.

Volume-independent mechanisms of hypertension in hemodialysis patients: clinical implications

The renin-angiotensin and sympathetic nervous systems are often activated in hemodialysis (HD) patients; the pathogenesis of this condition is discussed. Medications aimed at reducing renin and sympathetic activity may improve the cardiovascular prognosis, independent of its effect on blood pressure. This knowledge has important implications for the choice of treatment in HD patients.

HYPERTENSION IN HEMODIALYSIS PATIENTS: Role of Sodium and Volume in the Pathogenesis of Hypertension in Hemodialysis

Hypertension is a common finding in chronic hemodialysis (HD) patients. Cardiovascular (CV) disease is the leading cause of death in this population, and hypertension is a significant risk factor for CV events. Understanding the etiology of hypertension in chronic HD patients is critical in order to optimize treatment and reduce the morbidity and mortality associated with hypertension. Although the pathogenesis of hypertension in HD patients is multifactorial, two of the major risk factors are increased extracellular volume and sodium intake. Control of extracellular volume has been shown to normalize blood pressure (BP), but this normalization lags behind the extracellular volume contraction ("lag phenomenon"). A sodium load leads to an increase in BP by causing an increase in extracellular volume, resulting in a transient increase in cardiac output and an increase in total peripheral resistance. Sodium may be implicated in the hypertension of end-stage renal disease (ESRD) patients through hypervolemia-independent mechanisms. Aggressive control of extracellular volume and dietary sodium intake can normalize BP in chronic HD patients and reduce the morbidity associated with hypertension-related CV disease.

Measurement of Blood Volume During Hemodialysis is a Useful Tool to Achieve Safely Adequate Dry Weight by Enhanced Ultrafiltration

Chronic fluid overload and hypertension are highly prevalent in the dialysis population. Measurement of blood volume (BV) during hemodialysis (HD) may prove useful to achieve dry weight (DW). Twelve (12) chronic hemodynamically stable dialysis patients were randomly selected to participate in a pilot study. BV changes were measured using an online blood volume monitor (Hemoscan, Gambro AB, Stockholm, Sweden). As part of an initial observation phase, the magnitude of BV variation (deltaBV) in percentage and total UF volume (UF) in liters were recorded for each dialysis session, and the deltaBV/UF ratio was calculated. DW was subsequently reduced by 0.5 kg in all patients and the tolerance of the procedure was assessed. Attempted DW reduction was successful in seven patients, whereas it resulted in hypotension or symptoms in the other five cases. The deltaBV/UF ratio was found to be significantly lower in patients in whom attempted DW reduction was successful (2.47%/L vs. 3.45%/L, P < 0.05). Using receiver operating characteristic (ROC) curve analysis, a deltaBV/UF ratio of less than 2.6%/L offered the best overall prediction of successful DW reduction. These results suggest that measurement of BV changes during HD and calculation of the deltaBV/UF ratio are valuable tools for management of DW in clinically stable 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.

DAILY HEMODIALYSIS-SELECTED TOPICS: Cardiovascular Effects of Frequent Intensive Hemodialysis

Cardiovascular disease remains the leading cause of morbidity and mortality for patients with end-stage renal disease (ESRD). Frequent intensive hemodialysis (short daily hemodialysis [2 hours per session, six sessions per week] and nocturnal home hemodialysis [6 hours per session, five to six sessions per week]) has recently gained increasing popularity as an alternative to conventional hemodialysis (4 hours per session, three sessions per week). There is an emerging body of evidence that frequent intensive hemodialysis offers superior uremic toxin clearance, blood pressure control, and other cardiovascular outcomes. The goals of the present review are to systematically evaluate the available evidence in blood pressure control and cardiovascular outcomes in ESRD and the achievable changes after converting from conventional dialysis to frequent intensive hemodialysis, and to provide possible physiological explanations to account for these important changes of potent markers of adverse events in this patient population.

Sodium balance in hemodialysis therapy

Water and sodium overload is the predominant factor in the pathogenesis of hypertension in dialysis patients. In many dialysis patients, dry weight is not reached because of an imbalance between the interdialytic accumulation of water and sodium and the brief and discontinuous nature of routine dialysis therapy. During dialysis, sodium is removed by convection and to a lesser degree by diffusion. However, with supraphysiologic dialysate sodium concentrations, diffusive influx from dialysate may occur, especially in patients with low predialytic plasma sodium concentrations. Measuring sodium removal during dialysis is difficult and hampered by the variability in conventional sodium measurements. Ionic mass removal by continuous measurement of conductivity in the dialysate ports appears to be a promising tool for the approximation of sodium removal during dialysis. While the beneficial effects of concomitant water and sodium removal on blood pressure control in dialysis patients are undisputed, it is less well known whether a change in hydrosodium balance solely by reducing dialysate sodium is beneficial. Considering the inherent dangers of such an approach (intradialytic hemodynamic instability), the beneficial effects of strict dietary sodium restriction appear to be of much larger clinical benefit. It has become possible to individualize dialysate sodium concentration by means of online measurements of plasma conductivity and adjustment of dialysate conductivity by feedback technologies. The clinical benefits of this approach deserve further study. Still, reducing dietary sodium intake remains the most important tool in improving blood control in dialysis patients.

Prevalence, treatment, and control of hypertension in chronic hemodialysis patients in the United States

BACKGROUND

Hypertension is common in chronic hemodialysis patients, yet there are limited data on the epidemiology of hypertension in these patients in the United States.

METHODS

We assessed the prevalence, treatment, and control of hypertension in a cohort of 2535 clinically stable, adult hemodialysis patients who participated in a multicenter study of the safety and tolerability of an intravenous iron preparation. Hypertension was defined as an average predialysis systolic blood pressure >150 mm Hg or diastolic blood pressure >85 mm Hg, or the use of antihypertensive medications.

RESULTS

Hypertension was documented in 86% (n = 2173) of patients. The prevalence of hypertension, in contrast to that observed in the general population, did not increase linearly with age and was not affected by sex or ethnicity. Hypertension was controlled adequately in only 30% (n = 659) of the hypertensive patients. In the remaining patients, hypertension was either untreated (12% [252/2173]) or treated inadequately (58% [1262/2173]).

CONCLUSION

Control of hypertension, particularly systolic hypertension, in chronic hemodialysis patients in the United States is inadequate, despite recognition of its prevalence and the frequent use of antihypertensive drugs. Optimizing the use of medications and closer attention to nonpharmacologic interventions, such as adjustment of dry weight, a low-sodium diet, and exercise, may improve control.

Initial body mass indexes have contrary effects on change in body weight and mortality of patients on maintenance hemodialysis treatment

Malnutrition is a relevant risk factor for mortality for patients on maintenance hemodialysis treatment. In a retrospective study including 377 patients who began hemodialysis treatment between 1986 and 2001, we assessed the prevalence of different statuses of nutrition and the impact of the initial status of nutrition on the change in body weight and patient survival. We found an inverse relationship between body mass index (BMI, kg/m2) and the gain in body weight and BMI within 12 months of hemodialysis treatment. Underweight and normal weight patients had a substantial increase in these parameters, greatest in underweight subjects, whereas overweight and obese patients showed only a moderate increase or none (P =.0019, P =.00036). Adjusted mortality rates showed an inverse correlation with the initial BMI (P <.0001). There was a statistically significant difference in the mortality between patients with normal weight and overweight or obesity, respectively, showing a more favorable prognosis in overweight and obese patients (P =.0007; P =.022; log-rank, normal versus overweight, P =.012). Weight loss was the greatest independent risk factor for mortality in general. Adjusted hazard ratio of death was highest in underweight patients (3.999; CI, 2.708 to 5.905; P <.0001) and decreased to 2.251 (CI, 1.795 to 2.822; P <.0001) in normal weight, 1.927 (CI, 1.390 to 2.670; P <.0001) in overweight, and 1.651 (CI, 0.841 to 3.236; P =.1439) in obese subjects when patients with weight loss were compared with patients who preserved their initial weight or gained weight. Overall, the initial BMI has an influence on the change in body weight as well as on patient survival in general and in the case of weight loss in particular.

Mean arterial pressure and pulse pressure are associated with different clinical parameters in chronic haemodialysis patients

The mean arterial pressure (MAP) usually serves as an expression of blood pressure in patients on chronic haemodialysis (PCHD), instead of using solely systolic or diastolic pressure. Pulse pressure (PP) has been recognized as an important correlate of mortality in PCHD. We conducted this study in order to demonstrate clinical and biochemical determinants and variability of predialysis and postdialysis MAP and PP values. A total of 136 single haemodialysis (HD) treatments in 23 subjects (PCHD, 11 male and 12 female patients) were processed during 15 months. MAP before HD was in negative correlation with haemoglobin (P<0.001) and body mass index (BMI) (P<0.001), and in positive correlation with weekly erythropoietin dosage (P=0.017). MAP after HD was in negative correlation with haemoglobin (P<0.001), ultrafiltration per HD (P=0.015), and BMI (P=0.001), and in positive correlation with weekly erythropoietin dosage (P=0.003). PP before HD was in negative correlation with parathyroid hormone (PTH) level (P=0.020), haemoglobin (P<0.001), ultrafiltration per HD (P=0.001), and years on the chronic HD treatment (P=0.001), and in positive correlation with weekly erythropoietin dosage (P<0.001) and age (P<0.001). PP after HD was in significant negative correlation with PTH (P=0.015), haemoglobin (P=0.005), ultrafiltration per HD (P<0.001), BMI (P=0.003), and in positive correlation with weekly erythropoietin dosage (P<0.001) and age (P=0.004). Multiple regression analyses unveiled the strongest and negative correlations between MAP before HD and BMI (beta=-0.37, P=0.01); MAP after HD and haemoglobin (beta=-0.36, P=0.01); PP after HD and ultrafiltration/body weight ratio (beta=-0.41, P<0.001). The strongest and positive correlation was found between PP before HD and erythropoietin dosage per week (beta=0.51, P&<0.001). In conclusion, our findings support the assumption that PP and MAP are associated with different clinical parameters. PP values have advantages as the method of blood pressure expression.

[Atherosclerosis and uremia: signifance of non-traditional risk factors]

Arteriosclerosis, atherosclerosis and vascular calcification are causally related to the high morbidity and mortality of patients with chronic renal failure. Oxidative stress and carbonyl stress of uremia, dialysis procedure and/or intravenous iron therapy result in AGE (advanced glycation end-product), ALE (advanced lipoxidation end-product) and AOPP (advanced oxidation protein product) formation, favouring together with elevated CRP (C-reactive protein) levels the development of cardiovascular and cerebrovascular complications. Enhanced plasma levels of homocysteine and ADMA (asymmetric dimethylarginine) contribute to this process. In addition, in chronic renal insufficiency hyperphosphatemia and an enhanced calcium x phosphorus ion product are associated with the morbidity and mortality of the patients, particularly in the presence of fetuin deficiency. Phosphorus, AGEs and AOPPs, beside other factors, catalyze the conversion of vascular smooth muscle cells to osteoblast--like cells (particularly in the presence of monocytes/macrophages), resulting in bone matrix protein formation. Other risk factors, such as age, male sex, smoking, hypertension, diabetes, chronic inflammation, insulin resistance or dyslipidemia (enhanced non-HDL-cholesterol) also contribute to the atherosclerotic risk profile of the patient with chronic renal insufficiency. While there is growing understanding of the mechanisms involved in arteriosclerosis, atherosclerosis and vascular calcification in uremia, we are still missing effective therapeutic maneuvers for reduction of excess mortality in uremic patients.

Hypertension in chronic dialysis patients: pathophysiology, monitoring, and treatment

The prevalence of hypertension in the population with ESRD is very high, approaching 100% in some populations, and may account for the fact that cardiovascular disease continues to be the leading cause of morbidity and mortality in ESRD. The pathophysiology of hypertension in ESRD is reviewed, suggesting multifactorial causes; a dominant cause is that of volume expansion and an inappropriate increase in systemic vascular resistance because of activation of the renin-angiotensin system. The primary goal in the treatment of hypertension should be to attain a dry-weight and maintain volume control through limiting salt and fluid intake and ultrafiltration of excess fluids. If this approach is unsuccessful, an array of antihypertensive medications are available to help control blood pressure in patients with ESRD.

Effect of hypertension before beginning dialysis on survival of hemodialysis patients

BACKGROUND

The role of hypertension as a predictor of mortality in hemodialysis patients is controversial. The purpose of this study is to investigate the effect of hypertension before starting hemodialysis therapy on survival of patients without diabetes during renal replacement therapy.

METHODS

We reviewed 184 patients starting hemodialysis therapy. Variables studied were age, sex, renal disease, hypertension, comorbidity, vascular calcifications, left ventricular hypertrophy, body mass index, and albumin, cholesterol, and alkaline phosphatase levels. Regarding blood pressure control, three groups were considered: normotensive (NH), controlled hypertensive (c-HT), and uncontrolled hypertensive (uc-HT).

RESULTS

The Cox model was performed considering all-cause and cardiovascular mortality. The model was adjusted for age, sex, serum albumin level, vascular calcifications, history of hypertension, and comorbidity. Comorbidity included cardiovascular comorbidity. For all-cause mortality, comorbidity and history of uncontrolled hypertension were independent risk factors (comorbidity relative risk, 1.95; 95% confidence interval, 1.26 to 3.1; P = 0.003; uncontrolled hypertension relative risk, 1.79; 95% confidence interval, 1.15 to 2.8; P = 0.01). For cardiovascular mortality, uncontrolled hypertension was the main risk factor (relative risk, 2.93; 95% confidence interval, 1.68 to 5.12; P = 0.000). Mortality rates were 7.9/100 patient-years for NH, 8.7/100 patient-years for c-HT, and 14.1/100 patient-years for uc-HT patients.

CONCLUSION

This study suggests that uncontrolled hypertension in renal patients before starting dialysis therapy is a major risk factor for cardiovascular mortality during hemodialysis. Because hypertension usually starts in the initial stages of renal disease, we emphasize the importance of prompt and adequate control of blood pressure in this population.

Ambulatory blood pressure monitoring in chronic renal disease: technical aspects and clinical relevance

PURPOSE OF REVIEW

To evaluate the current value of ambulatory blood pressure monitoring in patients with chronic renal disease and end-stage renal disease.

RECENT FINDINGS

Ambulatory blood pressure monitoring has become an important tool in hypertension research and clinical practice. Its use in essential hypertension shows a strong predictive ability in the assessment of cardiovascular outcomes. In chronic renal failure and end-stage renal disease, the role of ambulatory blood pressure monitoring is still being actively evaluated, and available evidence shows that it is better than office blood pressure in predicting left ventricular hypertrophy and progression of renal dysfunction in patients with chronic renal failure. In end-stage renal disease, preliminary data suggest better prediction of mortality in hemodialysis patients in comparison with clinic blood pressures. The most conspicuous problems with the literature on this subject are small sample sizes and the paucity of longitudinal observational studies and intervention trials.

SUMMARY

Preliminary data and extrapolations from essential hypertension have justified a growing excitement about the use of ambulatory blood pressure monitoring in renal disease. However, further research will have to address the limitations of the available literature before generalization of its use is implemented.