Association between 24-hour blood pressure variability and chronic kidney disease: a cross-sectional analysis of African Americans participating in the Jackson heart study

Circadian blood pressure variability and associated factors among chronic kidney disease patients at Nekemte Town public Hospitals, West Oromia, Ethiopia: a comparative cross-sectional study

OBJECTIVE

This study aimed to assess the pattern of circadian blood pressure variability (CBPV) and associated factors among chronic kidney disease (CKD) patients admitted to Nekemte Town public Hospitals.

DESIGN

A hospital-based comparative cross-sectional study was conducted among 130 CKD patients from 01 October to 02 December 2022. Comparisons were performed between the groups using an independent t-test for CBPV (24-hour blood pressure (BP), daytime BP and night-time BP). The dipping pattern was compared by the χ2 test. Multiple logistic regression was used to determine the factors associated with non-dipping patterns in patients with hypertensive CKD (HCKD).

SETTING

Two public hospitals in the Nekemte town, Western Ethiopia.

PARTICIPANTS

The participants were two independent groups. Group I (HCKD=65) and group II (normotensive CKD (NCKD)=65).

RESULTS

The mean 24-hour SD of systolic blood pressure (SBP) was significantly different between HCKD and NCKD patients, 10.17±6.12 mm Hg versus 0.5.4±2.7 mm Hg, respectively (95% CI 0.02 to 1.77, p=0.043). The prevalence of SBP non-dippers was greater among HCKD than NCKD patients (83% vs 63%). Mean 24-hour SBP (95% CI 1.50 (1.15 to 1.96), p=0.003) and estimated glomerular filtration rate (eGFR) (95% CI 2.92 (1.21 to 47.06), p=0.038) were independently associated with non-dipping SBP in HCKD patients.

CONCLUSION

Compared with NCKD patients, HCKD patients had significantly greater CBPV. Compared with dippers, non-dippers had a lower mean eGFR.

Cardiovascular variability, sociodemographics, and biomarkers of disease: the MIDUS study

Introduction: Like heart rate, blood pressure (BP) is not steady but varies over intervals as long as months to as short as consecutive cardiac cycles. This blood pressure variability (BPV) consists of regularly occurring oscillations as well as less well-organized changes and typically is computed as the standard deviation of multiple clinic visit-to-visit (VVV-BP) measures or from 24-h ambulatory BP recordings (ABPV). BP also varies on a beat-to-beat basis, quantified by methods that parse variation into discrete bins, e.g., low frequency (0.04-0.15 Hz, LF). However, beat-to-beat BPV requires continuous recordings that are not easily acquired. As a result, we know little about the relationship between LF-BPV and basic sociodemographic characteristics such as age, sex, and race and clinical conditions. Methods: We computed LF-BPV during an 11-min resting period in 2,118 participants in the Midlife in the US (MIDUS) study. Results: LF-BPV was negatively associated with age, greater in men than women, and unrelated to race or socioeconomic status. It was greater in participants with hypertension but unrelated to hyperlipidemia, hypertriglyceridemia, diabetes, elevated CRP, or obesity. LF-diastolic BPV (DBPV), but not-systolic BPV (SBPV), was negatively correlated with IL-6 and s-ICAM and positively correlated with urinary epinephrine and cortisol. Finally, LF-DBPV was negatively associated with mortality, an effect was rendered nonsignificant by adjustment by age but not other sociodemographic characteristics. Discussion: These findings, the first from a large, national sample, suggest that LF-BPV differs significantly from VVV-BP and ABPV. Confirming its relationship to sociodemographic risk factors and clinical outcomes requires further study with large and representative samples.

Short-term blood pressure variability as a potential therapeutic target for kidney disease

Short-term blood pressure variability (BPV) measured with ambulatory blood pressure (BP) monitoring has been demonstrated to be significant in predicting various clinical outcomes. Short-term BPV is distinguished from long-term BPV based on the time interval in which BP fluctuations are measured. Increased short-term BPV has been linked to detrimental effects on the microvascular structure and contributes to subclinical organ damage in the heart, blood vessels, and kidneys, regardless of the average 24-h BP levels. Short-term BPV can be defined by various measures, including calculated metrics (standard deviation, coefficient of variation, average real variability, weighted standard deviation, variability independent of the mean) or dipping patterns. Nevertheless, the additional role of short-term BPV beyond the predictive value of average 24-h BPs or established risk factors for cardiovascular disease and kidney disease remains unclear. In particular, longitudinal studies that evaluate the association between short-term BPV and kidney function impairment are limited and no conclusive data exist regarding which short-term BPV indicators most accurately reflect the prognosis of kidney disease. The issue of how to treat BPV in clinical practice is another concern that is frequently raised. This paper presents a review of the evidence for the prognostic role of short-term BPV in kidney outcomes. Additionally, this review discusses the remaining concerns about short-term BPV that need to be further investigated as an independent risk modifier.

Hypertension in Chronic Kidney Disease: An Update on Diagnosis and Management

Hypertension (HTN) and chronic kidney disease (CKD) are pathophysiologic states that are intimately related, such that long-term HTN can lead to poor kidney function, and renal function decline can lead to worsening blood pressure (BP) control. HTN in CKD is caused by an interplay of factors, including salt and water retention, with extracellular volume expansion, sympathetic nervous system overactivity, renin-angiotensin-aldosterone system activation, and endothelial dysfunction. BP variability in the CKD population is significant, however, and thus requires close monitoring for appropriate management. With accumulating evidence, the diagnosis as well as management of HTN in CKD has been evolving in the last decade. In this comprehensive review based on current evidence and recommendations, we summarize the basics of pathophysiology, BP variability, diagnosis, and management of HTN in CKD with an emphasis on special populations with CKD.

Blood Pressure and Chronic Kidney Disease Progression: An Updated Review

Hypertension (HTN) is common in chronic kidney disease (CKD), and it may aggravate CKD progression. The optimal blood pressure (BP) value in CKD patients is not established yet, although systolic BP ≤130 mmHg is acceptable as a target. Continuous BP monitoring is essential to detect the different variants of high BP and monitor the treatment response. Various methods of BP measurement in the clinic office and at home are currently used. One of these methods is ambulatory BP monitoring (ABPM), by which BP can be closely assessed for even diurnal changes.

We conducted a non-systematic literature review to explore and update the association between high BP and the course of CKD and to review various BP monitoring methods to determine the optimal method for BP recording in CKD patients. PubMed, EMBASE, Google, Google Scholar, and Web Science were searched for published reviews and original articles on BP and CKD by using various phrases and keywords such as "hypertension and CKD", "CKD progression and hypertension", "CKD stage and hypertension", "BP control in CKD", "BP measurement methods", "diurnal BP variation effect on CKD progression", and "types of hypertension." We evaluated and discussed published articles relevant to the review objective. Before preparing the final draft of this article, each author was assigned a section of the topic to read, research deeply, and write a summary about the assigned section. Then a summary of each author's contribution was collected and discussed in several group sessions.

Early detection of high BP is essential to prevent CKD development and progression. Although the latest Kidney Disease Improving Global Outcomes (KDIGO) guidelines suggest that a systolic BP ≤120 mmHg is the target toprevent CKD progression, systolic BP ≤130 mmHg is universally recommended.ABPM is a promising method to diagnose and follow up on BP control; however, the high cost of the new devices and patient unfamiliarity with them have proven to be major disadvantages with regard to this method.

Measurement of Blood Pressure in Chronic Kidney Disease: Time to Change Our Clinical Practice - A Comprehensive Review

Chronic kidney disease (CKD) is extremely common all over the world and is strongly linked to cardiovascular disease (CVD). The great majority of CKD patients have hypertension, which raises the risk of cardiovascular disease (CVD), end-stage kidney disease, and mortality. Controlling hypertension in patients with CKD is critical in our clinical practice since it slows the course of the disease and lowers the risk of CVD. As a result, accurate blood pressure (BP) monitoring is crucial for CKD diagnosis and therapy. Three important guidelines on BP thresholds and targets for antihypertensive medication therapy have been published in the recent decade emphasizing the way we measure BP. For both office BP and out-of-office BP measuring techniques, their clinical importance in the management of hypertension has been well defined. Although BP measurement is widely disseminated and routinely performed in most clinical settings, it remains unstandardized, and practitioners frequently fail to follow the basic recommendations to avoid measurement errors. This may lead to misdiagnosis and wrong management of hypertension, especially in CKD patients. Here, we review presently available all BP measuring techniques and their use in clinical practice and the recommendations from various guidelines and research gaps emphasizing CKD patients.

24-h ambulatory blood pressure variability and hypertensive nephropathy in Han Chinese hypertensive patients

Blood pressure (BP) is characterized by spontaneous oscillation over time, which is described as BP variability (BPV). The current study aimed to investigate whether short‐term BPV was correlated with hypertensive nephropathy in Han Chinese individuals with hypertension. A single‐center prospective cohort study of 300 Han Chinese participants with hypertension was conducted in Taiwan. Five different BPV parameters were derived from ambulatory BP monitoring (ABPM), including standard deviation (SD), weighted SD (wSD), coefficient of variation (CoV), successive variation (SV), and average real variability (ARV). Renal event was defined as > 50% reduction in baseline estimated glomerular filtration rate (eGFR). The average age of the participants was 63.5 years. The baseline eGFR was 84.5 mL/min/1.73 m². The participants were divided into two groups according to the wSD of systolic BP (SBP). Survival was assessed via a Kaplan‐Meier analysis. During the 4.2‐year follow‐up, the participants with the highest SBP wSD tertile had a greater number of renal events (6.0%) than their counterparts (0.5%) (log‐rank test, p = .007). The Cox proportional hazard regression model was used to assess the independent effects of BPV, and results showed that 24‐h SBP (HR = 1.105; 95% CI = 1.020–1.197, p = .015) and 24‐h DBP (HR = 1.162; 95% CI = 1.004–1.344, p = .044) were independently associated with renal events. However, BPV parameters were only associated with renal events univariately, but not after adjusting for baseline characteristics, 24‐h mean BP, and office BP. Therefore, the risk of hypertensive nephropathy was independently associated with 24‐h mean BP, but not with ambulatory BPV, in Han Chinese participants with hypertension.

Cerebro-renal interaction and stroke

Stroke is an event causing a disturbance in cerebral function leading to death and disability worldwide. Both acute kidney injury and chronic kidney disease (CKD) are associated with an increased risk of stroke and cerebrovascular events. The underlying mechanistic approach between impaired renal function and stroke is limitedly explored and has attracted researchers to learn more for developing therapeutic intervention. Common risk factors such as hypertension, hyperphosphatemia, atrial fibrillation, arteriosclerosis, hyperhomocysteinemia, blood-brain barrier disruption, inflammation, etc. are observed in the general population, but are high in renal failure patients. Also, risk factors like bone mineral metabolism, uremic toxins, and anemia, along with the process of dialysis in CKD patients, eventually increases the risk of stroke. Therefore, early detection of risks associated with stroke in CKD is imperative, which may decrease the mortality associated with it. This review highlights mechanisms by which kidney dysfunction can lead to cerebrovascular events and increase the risk of stroke in renal impairment.

Twenty-four-hour versus clinic blood pressure levels as predictors of long-term cardiovascular and renal disease outcomes among African Americans

In Caucasian and Asian populations, evidence suggests that 24-h blood pressures (BP) are more predictive of long-term cardiovascular events than clinic BP. However, few long-term studies have evaluated the predictive value of 24-h BP phenotypes (24-h, daytime, nighttime) among African Americans (AA). The purpose of this study is to evaluate the added value of 24-h BP phenotypes compared to clinic BP in predicting the subsequent fatal and non-fatal cardiovascular/renal disease events in AA subjects. AA subjects (n = 270) were initially studied between 1994 and 2006 and standardized clinic BP measurements were obtained during screening procedures for a 3-day inpatient clinical study during which 24-h BP measurements were obtained. To assess the subsequent incidence of cardiovascular and renal disease events, follow-up information was obtained and confirmed by review of paper and electronic medical records between 2015 and 2017. During a mean follow-up of 14 ± 4 years, 50 subjects had one or more fatal or non-fatal cardiovascular/renal disease events. After adjustment for covariates, clinic systolic and diastolic BP were strongly associated with cardiovascular/renal disease events and all-cause mortality (p < 0.0001). Twenty-four-hour BP phenotypes conferred a small incremental advantage over clinic BP in predicting cardiovascular/renal events, which was limited to making a difference of one predicted event in 250-1,000 predictions depending on the 24-h BP phenotype. Nocturnal BP was no more predictive than the other 24-h BP phenotypes. In AA, 24-h BP monitoring provides limited added value as a predictor of cardiovascular/renal disease events. Larger studies are needed in AA to confirm these findings.

Short-Term Systolic Blood Pressure Variability and Kidney Disease Progression in Patients With Chronic Kidney Disease: Results From C-STRIDE

Background

It is unclear whether short‐term blood pressure variability is associated with renal outcomes in patients with chronic kidney disease.

Methods and Results

This study analyzed data from participants in the C‐STRIDE (Chinese Cohort Study of Chronic Kidney Disease) who had chronic kidney disease stages 1 to 4. Short‐term blood pressure variability was measured by calculating the weighted SD (w‐SD) of systolic blood pressure (SBP). Renal outcomes were defined as dialysis initiation and/or transplantation. Risk factors associated with w‐SD of SBP were evaluated by linear regression. Associations of short‐term SBP variability with renal outcomes were evaluated by Cox regression. In total, 1421 patients with chronic kidney disease were included in this study (mean age, 49.4±13.6 years; 56.2% men; estimated glomerular filtration rate, 50.5±29.3 mL/min per 1.73 m²; proteinuria, 0.9 [0.3–2.0] g/d). Mean w‐SD of SBP was 12.6±4.4 mm Hg. w‐SD of SBP was independently associated with older age, 24‐hour SBP, blood pressure circadian pattern, and angiotensin II receptor blocker treatment. During a median follow‐up of 4.9 years, 237 patients developed renal outcomes (37.01 per 1000 patient‐years). The incidence rate increased across the quartiles of w‐SD (log‐rank P=0.005). w‐SD of SBP was associated with an increased risk of renal outcomes, both as a continuous variable (hazard ratio [HR], 1.47; 95% CI, 1.09–1.99) and as a categorical variable (quartile 4 versus quartile 1: HR, 1.60; 95% CI, 1.08–2.36), independent of 24‐hour SBP, daytime SBP, and nighttime SBP.

Conclusions

Short‐term SBP was independently associated with the risk of dialysis initiation and/or transplantation in patients with chronic kidney disease.

Cardiovascular Disease and Mortality in Adults Aged ≥60 Years According to Recommendations by the American College of Cardiology/American Heart Association and American College of Physicians/American Academy of Family Physicians

In 2017, the American College of Cardiology/American Heart Association (ACC/AHA) and the American College of Physicians/American Academy of Family Physicians (ACP/AAFP) published blood pressure guidelines. Adults recommended antihypertensive medication initiation or intensification by the ACP/AAFP guideline receive the same recommendation from the ACC/AHA guideline. However, many adults ≥60 years old are recommended to initiate or intensify antihypertensive medication by the ACC/AHA but not the ACP/AAFP guideline. We compared atherosclerotic cardiovascular disease event rates according to antihypertensive treatment recommendations in the ACC/AHA and ACP/AAFP guidelines among adults ≥60 years old with systolic blood pressure ≥130 mm Hg or diastolic blood pressure ≥80 mm Hg in the REGARDS study (Reasons for Geographic and Racial Differences in Stroke) and the JHS (Jackson Heart Study). Among 4311 participants not taking antihypertensive medication at baseline, 11.4%, 61.2%, and 27.4% were recommended antihypertensive medication initiation by neither guideline, the ACC/AHA but not the ACP/AAFP guideline, and both guidelines, respectively. Atherosclerotic cardiovascular disease event rates (95% CI) for these groups were 3.4 (1.6-5.2), 18.0 (16.1-19.8), and 25.3 (21.9-28.6) per 1000 person-years, respectively. Among 7281 participants taking antihypertensive medication at baseline, 57.9% and 42.1% were recommended antihypertensive medication intensification by the ACC/AHA but not the ACP/AAFP guideline and both guidelines, respectively. Atherosclerotic cardiovascular disease event rates (95% CI) for these groups were 18.2 (16.7-19.7) and 33.0 (30.5-35.4) per 1000 person-years, respectively. In conclusion, adults recommended initiation or intensification of antihypertensive medication by the ACC/AHA but not the ACP/AAFP guideline have high atherosclerotic cardiovascular disease risk that may be reduced through treatment initiation or intensification.

Repeated ambulatory monitoring reveals an evening rise in blood pressure in a Japanese population

Recent studies have revealed 2 peaks in the onset of cardiovascular events, 1 in the morning and another in the evening. We evaluated whether blood pressure (BP) also rises in the morning/evening and identified the determinants of evening BP rise using 24-hour ambulatory BP monitoring for 7 consecutive days. We identified 2 BP peaks, 1 in the morning (0-3 hours after waking) and 1 in the evening (9-12 hours after waking). Subjects were subclassified according to the extent of evening BP rise: those in the top quartile (≥6.45 mm Hg, n = 34; ER group) vs all others. After adjustment for age, sex, and 24-hour systolic BP, evening BP rise was associated with the use of antihypertensive medications [odds ratio (OR), 3.57; 95% confidence interval (CI), 1.46-8.74; P = .01] and estimated glomerular filtration rate (OR, 0.96; 95% CI, 0.93-0.99; P = .04), confirming its association with antihypertensive medication use and renal dysfunction.

[Office and 44-hour ambulatory blood pressure and central haemodynamic parameters in the patients with end-stage renal diseases undergoing haemodialysis]

AIM

To assess the incidence of blood pressure (BP) control and various phenotypes of BP by comparing the results of office and 44-hour ambulatory brachial and central BP measurement in patients with end-stage renal disease (ESRD) on program hemodialysis (HD).

MATERIALS AND METHODS

In 68 patients ESRD receiving renal replacement therapy we evaluated office peridialysis BP and performed 44-hour ambu latory monitoring (ABPM) of brachial and central BP during peridialysis period using a validated oscillometric device BPLabVasotens (OOO "Petr Telegin"). Results were considered statistically significant with p&lt;0.05.

RESULTS

The frequency of control of peripheral office BP before the HD session was 25%, after - 23.5%; control of central BP - 48.6% and 49%, respectively. According to office measurement the frequency of systolic-diastolic hypertension was 44.1%, isolated systolic hypertension - 25%, isolated diastolic hypertension - 5.9%. The values of peripheral and central office systolic BP (SBP) before and after HD were not consistent with the corresponding mean and daily SBP levels for 44 hours and for the first and second days of the interdialysis period. The frequency of true uncontrolled arterial hypertension (AH) according to peripheral ABPM was 66.5%, masked uncontrolled AH - 9%. Circadian rhythm abnormalities for 44-h peripheral BP were detected in 77%, for central - in 76%. In 97% of patients agreement between phenotypes of the daily profile of peripheral and central BP was observed. 73% of patients had a significant increase in peripheral and central SBP and pulse pressure (PP) and an increase in the proportion of non-dippers from the 1st to the 2nd day.

CONCLUSION

Patients with ESRD on HD were characterized by poor control of BP control and predominance of unfavourable peripheral and central ambulatory BP phenotypes. A single measurement of clinical peripheral and central BP in the peridialysis period was not sufficient to assess the control of hypertension in this population. The 24-h BP profiles in the 1st and 2nd days of interdialysis period had significant differences.

Short-term blood pressure variability in nondialysis chronic kidney disease patients: correlates and prognostic role on the progression of renal disease

OBJECTIVE

In chronic kidney disease (CKD), few cross-sectional studies evidenced an association between short-term BP variability (BPV) derived from ambulatory blood pressure (ABP) monitoring and renal damage. However, no study has evaluated the association of short-term BPV with the risk of CKD progression.

METHODS

We performed a cohort study to assess the correlates and the predictive value for incident renal outcomes of short-term BPV in hypertensive patients with CKD stage G1-5. As measures of short-term BPV, we considered the weighted SD (W-SD), and the coefficient of variation of SBP (CV-24-h SBP). Primary outcome was a composite endpoint of ESRD (chronic dialysis or transplantation) or GFR decline of at least 50%.

RESULTS

We included 465 patients (63.5 ± 14.2 years; 54.7% men; eGFR: 44 ± 22 ml/min per 1.73 m; proteinuria: 0.2 [0.1-0.9] g/day); W-SD, CV-24-h SBP and 24 h SBP were 12.5 ± 3.3 mmHg, 11.1 ± 2.8% and 127 ± 16 mmHg, respectively. W-SD was independently associated with older age, history of cardiovascular disease, diagnosis of diabetic, hypertensive and polycystic nephropathy, and higher 24 h SBP whereas no association with eGFR and proteinuria was found. During follow-up (median, 6.4 years), 130 patients reached the renal outcome (107 ESRD and 23 GFR decline of ≥50%). Higher 24 h, daytime and night-time SBP robustly predicted the composite renal endpoint [1.18 (1.10-1.25) for 5 mmHg], whereas BPV as measured by the W-SD did not either when expressed as a continuous variable [hazard ratio 0.97 (95% CI 0.91-1.04)] or when categorized into tertiles [1.16 (0.70-1.92) and 0.95 (0.54-1.68) in II and III tertiles, respectively]. Similar findings were found with CV-24-h SBP.

CONCLUSION

In CKD patients, short-term BPV is strongly associated with 24 h, night-time and daytime BP but is independent from the eGFR and proteinuria and does not predict CKD progression.

Expert panel consensus recommendations for ambulatory blood pressure monitoring in Asia: The HOPE Asia Network

Hypertension is an important public health issue because of its association with a number of significant diseases and adverse outcomes. However, there are important ethnic differences in the pathogenesis and cardio-/cerebrovascular consequences of hypertension. Given the large populations and rapidly aging demographic in Asian regions, optimal strategies to diagnose and manage hypertension are of high importance. Ambulatory blood pressure monitoring (ABPM) is an important out-of-office blood pressure (BP) measurement tool that should play a central role in hypertension detection and management. The use of ABPM is particularly important in Asia due to the specific features of hypertension in Asian patients, including a high prevalence of masked hypertension, disrupted BP variability with marked morning BP surge, and nocturnal hypertension. This HOPE Asia Network document summarizes region-specific literature on the relationship between ABPM parameters and cardiovascular risk and target organ damage, providing a rationale for consensus-based recommendations on the use of ABPM in Asia. The aim of these recommendations is to guide and improve clinical practice to facilitate optimal BP monitoring with the goal of optimizing patient management and expediting the efficient allocation of treatment and health care resources. This should contribute to the HOPE Asia Network mission of improving the management of hypertension and organ protection toward achieving "zero" cardiovascular events in Asia.

Validity of a protocol to estimate patients' pre-morbid basal blood pressure

PURPOSE

The pre-illness basal mean arterial BP (MAP) is an important reference point to gauge the degree of relative hypotension among unwell patients. We aimed to assess mean bias, correlation, and agreement between basal MAP measured during nighttime ambulatory BP monitoring (ABPM) and basal MAP estimated using a standardized protocol.

MATERIALS AND METHODS

For a cohort of 137 consecutive patients, aged ≥40 years, who recently underwent ABPM, a blinded investigator estimated basal MAP from up to five most recent clinic BP measurements. Both basal MAP values, measured and estimated, were compared pairwise for each participant.

RESULTS

We traced a median of 4 [interquartile range 3-5] previous BP measurements per patient over a median period of 132 [interquartile range 55-277] days up until the ABPM test. The estimated basal MAP (mean 88 ± 8 mmHg) was linearly related (Pearson's r = 0.41, p = 0.0001) to the measured basal MAP (mean 88 ± 12 mmHg). Bland-Altman plot revealed a mean bias of 0.3 mmHg with agreement limits of ±22 mmHg.

CONCLUSIONS

The mean bias between estimated and measured values for basal MAP was insignificant and modest. When a recent nighttime ABPM is unavailable, a protocol based on recent clinic BP readings can be used to estimate patient's basal MAP.

STUDY REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12613001382763.

Ambulatory blood pressure variability: a conceptual review

Ambulatory blood pressure (ABP) has long been recognized by researchers as the gold standard of blood pressure (BP) measurement. Researchers and clinicians typically rely on the mean measure of ABP; however, there is considerable variability in the beat-to-beat BP. Although often ignored, this variability has been found to be an independent predictor of cardiovascular disease and mortality. The aim of this paper is to provide a conceptual review of ABP variability (ABPV) focusing on the following: associations between ABPV and health, whether ABPV is reliable, how to calculate ABPV, predictors of ABPV, and treatments for ABPV. Two future directions are discussed involving better understanding ABPV by momentary assessments and improving knowledge of the underlying physiology that explains ABPV. The results of this review suggest that the unique characteristics of ABPV provide insight into the role of BP variability in hypertension and subsequent cardiovascular illness.

Long-Term Visit-to-Visit Blood Pressure Variability and Renal Function Decline in Patients With Hypertension Over 15 Years

BACKGROUND

Visit-to-visit variability of systolic blood pressure (SBP) has been shown to contribute to cardiovascular events and all-cause mortality. However, little is known about its long-term effect on renal function. We aim to examine the relationship between visit-to-visit blood pressure variability (BPV) and decline in renal function in patients with hypertension and to determine the level of systolic BPV that is associated with significant renal function decline.

METHODS AND RESULTS

This is a 15-year retrospective cohort study of 825 hypertensive patients. Blood pressure readings every 3 months were retrieved from the 15 years of clinic visits. We used SD and coefficient of variation as a measure of systolic BPV. Serum creatinine was captured and estimated glomerular filtration rate was calculated at baseline, 5, 10, and 15 years. The mean SD of SBP was 14.2±3.1 mm Hg and coefficient of variation of SBP was 10.2±2%. Mean for estimated glomerular filtration rate slope was -1.0±1.5 mL/min per 1.73 m2 per year. There was a significant relationship between BPV and slope of estimated glomerular filtration rate (SD: r=-0.16, P<0.001; coefficient of variation: r=-0.14, P<0.001, Pearson's correlation). BPV of SBP for each individual was significantly associated with slope of estimated glomerular filtration rate after adjustment for mean SBP and other confounders. The cutoff values estimated by the receiver operating characteristic curve for the onset of chronic kidney disease for SD of SBP was 13.5 mm Hg and coefficient of variation of SBP was 9.74%.

CONCLUSIONS

Long-term visit-to-visit variability of SBP is an independent determinant of renal deterioration in patients with hypertension. Hence, every effort should be made to reduce BPV in order to slow down the decline of renal function.

The Cerebrovascular-Chronic Kidney Disease Connection: Perspectives and Mechanisms

Chronic kidney disease (CKD) is an independent risk factor for the development of cerebrovascular disease, particularly small vessel disease which can manifest in a variety of phenotypes ranging from lacunes to microbleeds. Small vessel disease likely contributes to cognitive dysfunction in the CKD population. Non-traditional risk factors for vascular injury in uremia include loss of calcification inhibitors, hyperphosphatemia, increased blood pressure variability, elastinolysis, platelet dysfunction, and chronic inflammation. In this review, we discuss the putative pathways by which these mechanisms may promote cerebrovascular disease and thus increase risk of future stroke in CKD patients.

Ambulatory Blood Pressure in Chronic Kidney Disease: Ready for Prime Time?

Hypertension is common in patients with chronic kidney disease (CKD) and is the most important modifiable risk factor for CKD progression and adverse cardiovascular events in these patients. Diagnosis and successful management of hypertension are critically dependent on accurate blood pressure (BP) measurement. This is most relevant to CKD patients, in whom BP control is difficult to achieve and in whom early antihypertensive treatment is imperative to prevent kidney and cardiovascular complications. Accumulated data indicate that ambulatory blood pressure monitoring (ABPM) is better in detecting hypertension than office BP measurement. ABPM is also a superior prognostic marker compared with office BP and has successfully identified hypertensive CKD patients at increased risk. Additionally, ABPM provides information on circadian BP variation and short-term BP variability, which is associated with cardiovascular and renal outcomes. This paper reviews the evidence for the usefulness of ABPM in detection and management of hypertension in CKD patients and discusses our current understanding of the pathophysiology of altered circadian BP rhythm and variability in CKD and the role of abnormal BP patterns detected by ABPM in relation to outcomes in CKD. In addition, this Review examines the emerging role of antihypertensive chronotherapy to tailor BP management to the circadian BP pattern abnormality detected by 24-hour ABPM.

Evaluation of Renal-Hepatic Functional Indices and Blood Pressure Based on the Progress of Time in a Rat Model of Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is defined as either kidney damage or a decline in renal function as determined by a decreased glomerular filtration rate (GFR) for three months or longer. CKD is an important risk factor for mortality.

OBJECTIVES

The aim of this study was to evaluate the effects of CKD on renal-hepatic functional indices and blood pressure in 5/6 nephrectomized (5/6 Nx) rats over the course of nine months.

MATERIALS AND METHODS

Male Wistar rats were subjected to either 5/6 Nx or sham operations (n = 8). Members of the sham group underwent the same procedure without surgical reduction of the kidney mass. For all animals, body weight (BW), serum creatinine (Cr), blood urea nitrogen (BUN), alanine transaminase (ALT), and aspartate transaminase (AST) levels were measured before and after surgery. After two-, three-, six-, and nine-month intervals, blood was collected to assay renal and hepatic functional indices. Tail-cuff blood pressure was recorded in each month after surgery.

RESULTS

BW was lower for the 5/6 Nx group rats after the operations compared with the BW of those in the sham operation group. Furthermore, the 5/6 Nx group showed elevations in blood pressure, Cr, BUN, ALT, and AST levels compared with the sham group over the course of time.

CONCLUSIONS

In summary, CKD induced by the 5/6 Nx model caused hypertension and increased serum levels of Cr, BUN, ALT, and AST. These changes are augmented by the progress of time.