Ambulatory blood pressure and the kidney

During the last few years there has been a renewed interest in blood-pressure-induced kidney damage, due to a progressive increase in the incidence and prevalence of hyipertension and vascular diseases as a cause of end-stage renal disease (ESRD). The need to prevent ESRD demands continued efforts to achieve the early identification of persons with hypertension who are at risk and to provide them with effective antihypertensive therapy. Ambulatory blood pressure monitoring (ABPM) has been used successfully to assess blood pressure values and identify risk markers for cardiovascular diseases. A logical approach would be to use it also to identify those for ESRD. For hypertensive and type 1 diabetics ABPM data usually have a stronger correlation to the presence and magnitude of microalbuminuria than do routine office blood pressure measurements. The best Pearson correlation coefficients for relationship between ambulatory blood pressure values and urinary excretion of albumin were obtained with nocturnal blood pressure regardless of whether systolic, diastolic or mean blood pressure were considered. Moreover, high percentages of non-dippers have been found among subjects with renal failure, subjects undergoing dialysis (haemofiltration, peritoneal dialysis, continuous ambulatory peritoneal dialysis (CAPD), subjects with renovascular hypertension and with cystic kidney disease, subjects who have had a kidney transplant and subjects with cyclosporine-induced hypertension. Finally, ABPM seems to be prognostic for development of proteinuria in some refractory hypertensives. Whether higher nocturnal blood pressure values and the non-dipping pattern constitute a cause or are consequences of renal disease should be addressed in prospective studies. Assessment of nocturnal blood pressure seems to be an important tool in the management of patients with hypertensive-related renal disease and of patients who are susceptible to developing it.     

Ambulatory blood pressure monitoring.

This paper will briefly summarize the available evidence on the diagnostic and prognostic relevance of a number of parameters derived from the analysis of 24 hour ambulatory blood pressure recordings. These parameters include the 24 h average blood pressure values, the difference between daytime and nighttime blood pressure, the difference between clinic blood pressure and daytime average blood pressure as a surrogate measure of the "white coat effect", and 24 hour blood pressure variability as quantified by the standard deviation of the 24 hour average value.     

Ambulatory blood pressure patterns in children with chronic kidney disease

Ambulatory blood pressure (BP) monitoring (ABPM) is the best method of detecting abnormal BP in patients with chronic kidney disease (CKD), whose hypertension may be missed with casual BP measurements. We report ABPM findings in 332 children 1 year after entry in the Chronic Kidney Disease in Children cohort study. All of the subjects underwent casual and ambulatory BP measurement. BP was categorized based on casual and ABPM results into normal (42%), white-coat (4%), masked (35%), and ambulatory (14%) hypertension. Only half of the subjects had a normal ABPM. BP load was elevated (>25%) in 52% (n = 172), whereas mean BP was elevated in 32% (n = 105). In multivariate analysis, those using an angiotensin-converting enzyme inhibitor were 89% more likely to have a normal ABPM than those who did not report using an angiotensin-converting enzyme inhibitor (odds ratio, 1.89 [95% CI, 1.17-3.04]). For every 20% faster decline in annualized glomerular filtration rate change, the odds of an abnormal ABPM increased 26% (odds ratio, 1.26 [95% CI, 0.97-1.64]). A 2.25-fold increase in urine protein:creatinine ratio annualized change was associated with a 39% higher odds of an abnormal ABPM (odds ratio, 1.39 [95% CI, 1.06-1.82]). Abnormalities on ABPM are common in children with chronic kidney disease and are strongly associated with known risk factors for end-stage renal disease. Individuals on angiotensin-converting enzyme inhibitors were less likely to have abnormal ABPM, suggesting a possible therapeutic intervention. ABPM should be used to monitor risk and guide therapy in children with chronic kidney disease.     

Ambulatory blood pressure and cardiovascular risk in chronic kidney disease

Diagnosis of hypertension is critically dependent on accurate blood pressure (BP) measurement, especially in patients with chronic kidney disease (CKD), in whom early antihypertensive treatment is imperative to prevent cardiovascular events. Ambulatory BP monitoring (ABPM) has successfully identified hypertensive patients at increased risk, but its role in management of CKD patients is not well defined. Loss of the nocturnal decline in BP, which is common in CKD, is associated with adverse cardiovascular events. Increased BP variability has been documented as related to worse outcome, and patients on dialysis are subject to marked BP swings. Traditional measurement in the office fails to provide a thorough picture of the 24-hour BP pattern in CKD patients. Thus, ABPM appears mandatory to better define the hypertensive status in these subjects because it provides information on diurnal BP rhythm and variability and allows identification of subjects with white-coat and masked hypertension.     

Ambulatory blood pressure during antihypertensive therapy guided by conventional pressure

Subjects with elevated conventional clinic or office blood pressure (CBP) may have normal ambulatory blood pressure (ABP). The purpose of this review is to summarize studies in which ABP was monitored while the initiation or intensification of antihypertensive therapy was guided by CBP. These studies show that ABP does not decrease or decreases only slightly in response to treatment in subjects with elevated CBP and low ABP, whereas the CBP is significantly reduced in such patients.     

Ambulatory blood pressure monitoring

Ambulatory blood pressure monitoring (ABPM) is becoming widely accepted as a clinically useful tool for assessing cardiovascular risk in hypertensive patients, although it is not generally recognized for reimbursement in the United States. There are now six major prospective studies, all of which have shown that ABPM gives a better prediction of risk than conventional clinic measurement. A corollary of these findings is that patients with white coat hypertension have been found to be at relatively low risk. The major clinical indications include patients with newly diagnosed hypertension, suspected white coat hypertension, and refractory hypertension. White coat hypertension is common during pregnancy and may lead to unnecessary cesarean sections.     

Ambulatory blood pressure monitoring

Ambulatory blood pressure monitoring (ABPM) is becoming widely accepted as a clinically useful tool for assessing cardiovascular risk in hypertensive patients, although it is not generally recognized for reimbursement in the United States. There are now six major prospective studies, all of which have shown that ABPM gives a better prediction of risk than conventional clinic measurement. A corollary of these findings is that patients with white coat hypertension have been found to be at relatively low risk. The major clinical indications include patients with newly diagnosed hypertension, suspected white coat hypertension, and refractory hypertension. White coat hypertension is common during pregnancy and may lead to unnecessary cesarean sections.     

Ambulatory blood pressure measurement in young normotensive patients with autosomal dominant polycystic kidney disease.

INTRODUCTION: Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic disorder causing chronic kidney disease in adults. Hypertension occurs early and frequently precedes the development of renal failure. It has been shown that clinically normotensive young adults with ADPKD exhibit increased left ventricular mass and left ventricular mass index (LVMI), which contributes to the increased cardiovascular risk in these patients. We set out to investigate whether normotensive patients have a prehypertensive state that could account for their increased LVMI. METHODS: Patients with ADPKD followed as outpatients were selected if they were aged between 21-30 years, were normotensive (office and sporadic blood pressure < 140/90 without medication), and had normal renal function (GFR > 90 ml/min). Normotensive controls aged between 21-30 years were selected, all with normal renal ultrasound, serum creatinine, dipstick analysis and microalbuminuria /creatinine ratio. Patients and controls underwent 24-hour ambulatory blood pressure measurement (ABPM) according to the local protocol. RESULTS: Systolic (124.7 +/- 7.6 vs. 115.2 +/- 6.9; p < 0.0001), diastolic (77.3 +/- 6.3 vs. 70.5 +/- 3.9; p < 0.0001) and mean (92.7 +/- 8.5 vs. 85.7 +/- < 0.001) 24-hour blood pressure was significantly higher in patients with ADPKD compared to controls. Statistically significant differences were also found when daytime and night-time periods were analyzed separately. Hypertension on ABPM was diagnosed in 6 patients but differences in the ABPM profile persisted even when these patients were excluded from the analysis. CONCLUSION: In young adults with ADPKD there is a prehypertensive state that can be detected using ABPM.     

Ambulatory blood pressure monitoring in clinical practice.

Ambulatory blood pressure monitoring provides a more reliable estimate of blood pressure and its diurnal variability than casual blood pressure measurement. However, the data supporting the link between cardiovascular risk and blood pressure are based almost entirely on casual, or office-based, blood pressure readings, and this form of measurement continues to be the primary factor in clinical decision making. In recent years, compelling evidence from research centers around the world has shown that ambulatory blood pressure measurements correlate more closely with the target organ complications of hypertension and predictions of future cardiovascular events than either casual office or home blood pressure measurements. Improvements in the technology have resulted in ambulatory blood pressure monitors that are increasingly accurate and unobtrusive. As evidence supporting its use continues to mount, the role of ambulatory blood pressure monitoring in clinical medicine can be expected to increase significantly.     

Ambulatory blood pressure monitoring and borderline hypertension.

Blood pressure fluctuates during daytime hours in response to changes in activities and to daily life stressors. Lifestyle factors may influence changes in blood pressure through a modulation of the sympathetic nervous system s activity, which is often elevated in subjects with borderline hypertension. In the HARVEST smoking, consumption of coffee, intake of alcohol, physical activity habits, and use of oral contraceptives influenced daytime blood pressure to a greater extent than did office blood pressure and had an effect on sympathetic tone (determined by measuring levels of urinary catecholamines). Subjects with borderline hypertension have a greater than normal risk of cardiovascular morbidity and mortality, but few data on the relation between ambulatory blood pressure and hypertensive complications during the early stage of hypertension are available. In the HARVEST the impact of ambulatory blood pressure on the walls of the left ventricle and on left ventricular mass in women was remarkable, whereas it was weak for men. The assessment of left ventricular systolic function confirmed that ejective performance in many young borderline hypertensive subjects is greater than normal. However, in 9.2% of the HARVEST participants left ventricular contractility evaluated by midwall measurement was found to be depressed. Although the prevalence of microalbuminuria (rate of excretion of urinary albumin > or = 30mg/24h) appeared to be low (6.1%), rate of excretion of albumin was highly statistically significantly correlated to 24h blood pressure. Ambulatory blood pressure monitoring is useful for identifying those borderline hypertensive subjects for whom antihypertensive treatment should be started.