Blood Pressure Measurement: A KDOQI Perspective

Revisiting resistant hypertension in kidney disease

PURPOSE OF REVIEW

As compared to controlled or uncontrolled hypertension, resistant hypertension in patients with chronic kidney disease (CKD) poses a significantly increased healthcare burden due to greater target end-organ damage including cardiovascular disease and CKD progression. Patients with CKD have two to three times higher risk of developing resistant hypertension. True resistant hypertension needs to be distinguished from apparent treatment resistant hypertension (aTRH); however, it is usually not possible in epidemiological studies. Moreover, impact of contemporary guidelines changes in the target blood pressure (BP) goal to less than 130/80 mmHg remains to be determined.

RECENT FINDINGS

Up to half of patients with CKD meet aTRH criteria using 2017 ACC/AHA target BP less than 130/80 mmHg. Excess sodium retention in extracellular and tissue compartment remains the cornerstone cause of resistance to the treatment in CKD. Maximizing and optimizing the diuretic regimen in addition to dietary sodium restriction plays a critical role in these patients. Management requires a trustworthy provider-patient relationship facilitating identification and intervention for the barriers restricting the uptake of lifestyle modifications and medications. Recently, renal denervation has been approved and many other novel agents are on the horizon for treatment of true resistant hypertension associated with CKD.

SUMMARY

This review discusses the latest in the pathophysiology, definition, identification and treatment strategies of resistant hypertension in individuals with CKD. Further investigations are required to identify the prevalence, future implication and treatment outcome data for true resistant hypertension associated with CKD.

Immune checkpoint activity exacerbate renal interstitial fibrosis progression by enhancing PD-L1 expression in renal tubular epithelial cells

Renal interstitial fibrosis (RIF) is often associated with inflammatory cell infiltration and no effective therapy. Programmed death cell-1 (PD-1) and its ligand PD-L1 were playing critical roles in T cell coinhibition and exhaustion, but the role in RIF is unclear. Here the data analyses of serum from 122 IgA nephrology (IgAN) patients showed that high level of soluble PD-1(sPD-1) was an independent risk factor for RIF and renal function progression. PD-L1 was also overexpressed in renal interstitial tissues from both IgAN patients with high level of sPD-1 and the unilateral ureteral obstruction (UUO) mouse. PD-L1 was significantly overexpressed in HK-2 cells with upregulated collagen and α-SMA when stimulated by inflammation or hypoxia in vitro. Additionally, matrix metalloproteinases (MMP-2) could increase the level of sPD-1 in culture supernatant when added in co-culture system of HK-2 and jurkat cells, which implied serum sPD-1 of IgAN might be cleaved by MMP-2 from T cells infiltrated into the tubulointerstitial inflammatory microenvironment. Crucially, injection of PD-L1 fusion protein, the blocker of sPD-1, could ameliorate kidney fibrosis in UUO mice by increasing T cell coinhibition and exhaustion, suggesting the therapeutic potential of PD-L1 fusion targeting for renal fibrosis. Take together, it reveals a novel causal role of sPD-1 in serum and PD-L1 of renal interstitial tissues in the development of renal fibrosis of IgAN, and targeting sPD-1 in serum by PD-L1 fusion protein is a potential therapeutic approach to prevent renal fibrosis of IgAN.

Associations between the Serum Triglyceride Level and Kidney Outcome in Patients with Chronic Kidney Disease: The Fukuoka Kidney disease Registry Study

AIMS

Hypertriglyceridemia is a risk factor for chronic kidney disease (CKD). However, whether or not it predicts the risk of CKD progression is unknown. This study evaluated the association between serum triglyceride (TG) levels and kidney disease progression in patients with non-dialysis-dependent CKD.

METHODS

The Fukuoka Kidney disease Registry (FKR) study was a multicenter, prospective longitudinal cohort study. In total, 4,100 patients with CKD were followed up for 5 years. The primary outcome was the incidence of CKD progression, defined as a ≥ 1.5-fold increase in serum creatinine level or the development of end-stage kidney disease. The patients were divided into quartiles according to baseline serum TG levels under non-fasting conditions: Q1 ＜87 mg/dL; Q2, 87-120 mg/dL; Q3, 121-170 mg/dL, and Q4 ＞170 mg/dL.

RESULTS

During the 5-year observation period, 1,410 patients met the criteria for CKD progression. The multivariable-adjusted Cox proportional hazards model showed a significant association between high serum TG level and the risk of CKD progression in the model without macroalbuminuria as a covariate (multivariable hazard ratio[HR] for Q4 versus Q1, 1.20; 95% CI, 1.03-1.41; P=0.022), but the significance disappeared after adjusting for macroalbuminuria (HR for Q4 versus Q1, 1.06; 95% CI, 0.90-1.24; P=0.507).

CONCLUSIONS

The present findings suggest that individuals with high serum TG levels are more likely to develop CKD progression than those without; however, whether or not higher serum TG levels reflect elevated macroalbuminuria or lead to CKD progression via elevated macroalbuminuria is unclear.

Effect of overweight/obesity and metabolic syndrome on frailty in middle-aged and older Japanese adults

Background

The potential for developing frailty exists in middle-aged and older adults. While obesity and metabolic syndrome (MetS) increase the risk of frailty in older adults, this relationship remains unclear in middle-aged adults, who are prone to developing lifestyle-related diseases.

Objective

To examine the effect of overweight/obesity and MetS on frailty development in middle-aged and older Japanese adults using real-world data.

Methods

This nationwide cohort study used exhaustive health insurance claims data of 3,958,708 Japanese people from 2015 to 2019 provided by the Japan Health Insurance Association. Participants aged ≥35 and < 70 years who received health checkups in 2015 were included. Multivariate logistic regression was used to assess the effect of body mass index (BMI) and MetS or MetS components (i.e., diabetes, hypertension, and dyslipidemia) in 2015 on frailty risk assessed using the hospital frailty risk score in 2019. Additionally, a subgroup analysis was performed to examine the interaction effects of MetS components and 4-year weight change (%) on frailty risk among participants who were overweight and obese (BMI ≥25 kg/m2).

Results

In 2019, 7204 (0.2%) and 253,671 (6.4%) participants were at high and intermediate frailty risks, respectively. Obesity and MetS were independently associated with intermediate/high frailty risk (odds ratio (OR) 1.36, p < 0.05; OR 1.23, p < 0.05, respectively) and high frailty risk (OR 1.80, p < 0.05; OR 1.37, p < 0.05, respectively) in all participants. Although all MetS components were frailty risk factors, these effects diminished with age in both sexes. Subgroup analysis of patients with diabetes revealed that 5%-10% weight loss was associated with reduced frailty risk in both sexes.

Conclusions

Obesity, MetS, and MetS components were independent frailty risk factors in middle-aged and older Japanese adults. Weight loss of up to 10% over 4 years prevented frailty in patients with diabetes who were overweight and obese.

Systolic Blood Pressure and the Risk of Kidney Replacement Therapy and Mortality in Patients with Chronic Kidney Disease Stages 4-5

INTRODUCTION

In patients with chronic kidney disease stages 4 and 5 (CKD stages 4-5) without dialysis and arterial hypertension, it is unknown if the values of systolic blood pressure (SBP) considered in control (<120 mm Hg) are associated with kidney replacement therapy (KRT) and mortality.

METHODS

In this retrospective cohort study, hypertensive CKD stages 4-5 patients attending the Renal Health Clinic at the Hospital Civil de Guadalajara were enrolled. We divided them into those that achieved SBP <120 mm Hg (controlled group) and those who did not (>120 mm Hg), the uncontrolled group. Our primary objective was to analyze the association between the controlled group and KRT; the secondary objective was the mortality risk and if there were subgroups of patients that achieved more benefit. Data were analyzed using Stata software, version 15.1.

RESULTS

During 2017-2022, a total of 275 hypertensive CKD stages 4-5 patients met the inclusion criteria for the analysis: 62 in the controlled group and 213 in the uncontrolled group; mean age 61 years; 49.82% were male; SBP was significantly lower in the controlled group (111 mm Hg) compared to the uncontrolled group (140 mm Hg); eGFR was similar between groups (20.41 mL/min/1.73 m2). There was a tendency to increase the mortality risk in the uncontrolled group (HR 6.47 [0.78-53.27]; p = 0.082) and an association by the Kaplan-Meir analysis (Log-rank p = 0.043). The subgroup analysis for risk of KRT in the controlled group revealed that patients ≥61 years had a lower risk of KRT (HR 0.87 [95% CI, 0-76-0.99]; p = 0.03, p of interaction = 0.005), but no differences were found in the subgroup analysis for mortality. In a follow-up of 1.34 years, no association was found in the risk of KRT according to the controlled or uncontrolled groups in a multivariate Cox analysis.

CONCLUSION

In a retrospective cohort of patients with CKD stages 4-5 and hypertension, SBP >120 mm Hg was not associated with risk of KRT but could be associated with the risk of death. Clinical trials are required in this group of patients to demonstrate the impact of reaching the SBP goals recommended by the KDIGO guidelines.

Approach to Diagnosis and Management of Hypertension: A Comprehensive and Combined Pediatric and Adult Perspective

The global prevalence of primary hypertension has been increasing both in children and in the adolescent and adult populations and can be attributed to changes in lifestyle factors with an obesity epidemic, increased salt consumption, and sedentary lifestyles. Childhood blood pressure is the strongest predictor of adult hypertension. Although hypertension in adults is associated strongly with an increased risk for cardiovascular disease, chronic kidney disease, and mortality, outcomes in children are defined less clearly. In adults, major guidelines agree on a threshold of less than 120/80 mm Hg as the optimal blood pressure (BP) and recommend a target of less than 130/80 mm Hg for treatment in most cases. In children, international pediatric guidelines recommend using thresholds based on the normative distribution of BP in healthy normal-weight children. Out-of-office BP assessment is extremely useful for confirming the diagnosis of hypertension and monitoring response to treatment. Lifestyle modifications are instrumental whether coupled or not with pharmacologic management. New agents such as nonsteroidal mineralocorticoid-receptor antagonists, aminopeptidase A inhibitors, aldosterone synthase inhibitors, and dual endothelin antagonists hold significant promise for resistant hypertension. The transition from pediatric to adult care can be challenging and requires careful planning and effective coordination within a multidisciplinary team that includes patients and their families, and pediatric and adult providers.

Association between physical activity and resistant hypertension in treated hypertension patients: analysis of the national health and nutrition examination survey

INTRODUCTION

Current guidelines suggest that regular aerobic training might lower blood pressure in hypertensive individuals. However, evidence linking resistant hypertension (RH) with total daily physical activity (PA), including work-, transport-, and recreation-related PA, is limited. Therefore, this study assessed the association between daily PA and RH.

METHOD

A cross-sectional study was conducted using data acquired from a nationwide survey in the US (the National Health and Nutrition Examination Survey, NHANES). The weighted prevalence of RH was calculated, and moderate and vigorous daily PA was assessed using the Global Physical Activity Questionnaire (GPAQ). A multivariate logistic regression model determined the association between daily PA and RH.

RESULTS

A total of 8,496 treated hypertension patients were identified, including 959 RH cases. The unweighted prevalence of RH among treated hypertension cases was 11.28%, while the weighted prevalence was 9.81%. Participants with RH had a low rate of recommended PA levels (39.83%), and daily PA and RH were significantly associated. PA exhibited significant dose-dependent trends with a low probability of RH (p-trends < 0.05). Additionally, participants with sufficient daily PA had a 14% lower probability of RH than those with insufficient PA [fully adjusted odds ratio (OR) = 0.86; 95% confidence interval (CI) = 0.74-0.99).

CONCLUSION

The present study revealed that RH has an incidence of up to 9.81% in treated hypertension patients. Hypertensive patients tended to be physically inactive, and insufficient PA and RH were significantly associated. Sufficient daily PA should be recommended to reduce the RH probability among treated hypertension patients.

Comparison between central and automated peripheral blood pressure measurement for early detection of kidney dysfunction in hypertensive patients

BACKGROUND

There is a close relationship between blood pressure levels and the risk of cardiovascular events, strokes, and kidney disease. For many years, the gold standard instrument for blood pressure measurement was a mercury sphygmomanometer and a stethoscope, but this century-old technique of Riva-Rocci/Korotkov is being progressively removed from clinical practice. Central blood pressure is considered better than peripheral blood pressure in predicting cardiovascular events, as it assesses wave reflections and viscoelastic properties of the arterial wall which make systolic and pulse pressures vary from central to peripheral arteries, but mean blood pressure is constant in the conduit arteries.

METHODS

The study included 201 patients with primary hypertension (108 patients with chronic kidney disease and 93 patients without kidney disease). All patients underwent blood pressure measurement by OMRON M2 and Mobil-O-Graph devices, kidney function assessment and abdominal ultrasonography.

RESULTS

Patients with chronic kidney disease were significantly older (60.02 ± 9.1 vs. 55.33 ± 8.5; P < 0.001), with longer duration of hypertension (7.56 ± 5.9 vs. 6.05 ± 5.8; P = 0.020) in comparison to those without chronic kidney disease. Automated peripheral measurement of systolic blood pressure, diastolic blood pressure and pulse pressure were significantly higher in comparison to central blood pressure. Patients with chronic kidney disease had significantly higher augmentation index (24.06 ± 12.6 vs. 19.02 ± 10.8; P < 0.001) and pulsed wave velocity (8.66 ± 1.5 vs. 8.69 ± 6.8; P = 0.004) in comparison to those without chronic kidney disease. Augmentation index had positive correlation with pulse wave velocity (r = 0.183, P = 0.005). There was negative correlation between both pulse wave velocity and augmentation index and estimated glomerular filtration rate (r = -0.318, P < 0.001), and (r = -0.236, P < 0.001), respectively. Hence, arterial stiffness parameters are good positive test for prediction of chronic kidney disease.

CONCLUSION

There is a strong agreement between non-invasive centrally and automated peripherally measured blood pressure in diagnosis of hypertension. But non-invasive central measurements are preferred over automated measurements for early prediction and detection of renal impairment.

Prevalence of hypertension and correlation with mental health in women with burning mouth syndrome: A case-control study

Background

The relationship between hypertension (HTN) and chronic pain is still a matter of debate, and its prevalence in patients with burning mouth syndrome (BMS) has never been evaluated. This study aimed to assess the prevalence of HTN in women with BMS and to evaluate its relationship with potential predictors such as risk factors for cardiovascular diseases, pain, and mental health status analyzing differences with healthy women.

Methods

In total, 250 women with BMS (WBMS) were prospectively recruited and compared with an equal number of healthy women (HW) matched for age. Education, body mass index, smoke and alcohol consumption, intensity and quality of pain, and psychological profile were further investigated to identify the potential predictors of HTN. Specifically, pain assessment [the Numeric Rating Scale (NRS) and Short-Form McGill Pain Questionnaire (SF-MPQ)] and psychological assessment [Hamilton Rating Scale for Depression and Anxiety (HAM-D and HAM-A), Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale (ESS)] was carried out for the participants.

Results

HTN was found in 128 (51.2%) WBMS and 76 (30.4%) HW (p < 0.001^**). The scores of the NRS, SF-MPQ, HAM-D, HAM-A, and PSQI were statistically significantly higher in the WBMS than in the HW (p < 0.001^**). A strongly linear correlation between HTN and employment status, systemic diseases, and education level (p < 0.001^**) was found in WBMS, while a strong correlation between HTN and employment status, hypercholesterolemia, systemic diseases, and drug consumption was found in HW (p < 0.001^**). No statistically significant correlation was found between HTN and pain, anxiety, depression, and sleep disturbances.

Conclusion

These results suggest that WBMS showed a higher prevalence of HTN compared with controls. Unemployed WBMS with lower education and other systemic comorbidities are at an increased risk of developing HTN. HTN is associated with alteration in the vascular structure and function of the brain, and these processes accelerate brain aging, which contributes to a reduction in intracortical connectivity, thus affecting the modulatory system of control of pain in patients with BMS, independently of their mental health assessment. Predictors that may underlie this association remain unclear, taking into account the differences found in HW, and should be further elucidated.

The reliability of patient blood pressure self-assessments - a cross-sectional study

OBJECTIVE

Home blood pressure monitoring (HBPM) is an increasingly important tool in managing hypertension (HTN); however, its efficacy depends on its accuracy. This study aimed to explore the differences between blood pressure (BP) measurements conducted by patients and medical professionals and the patient demographic factors correlating with inaccurate self-measured BP levels.

METHODS

One hundred hypertensive patients completed a questionnaire inquiring about their health status and HBPM procedures and were filmed while measuring their BP using their own devices. A researcher then measured the patients' BP using a calibrated sphygmomanometer to assess the accuracy of patient-performed readings. This cross-sectional study was conducted in five primary healthcare centers in Kraków, Poland.

RESULTS

The mean differences in systolic and diastolic BP readings by patients and researchers were 8.36 mmHg (SD = 10.90 mmHg) and 2.16 mmHg (SD = 9.12 mmHg), respectively. Inaccuracies in patient BP measurements were associated with a less than high school education level, patients' age, and a family history of HTN.

CONCLUSION

Patient self-measured BP levels were higher than researcher values, likely due to a higher patient error rate. Healthcare providers must increase training regarding correct HBPM techniques offered to patients; such efforts should be directed at all hypertensive patients, emphasizing the most error-prone demographics.

Timed-averaged blood pressure showed a J-curve association with stroke in elderly chronic kidney disease patients

BACKGROUND

The risk factors for stroke in elderly patients with chronic kidney disease (CKD) are not well understood. This study aimed to explore the influence of systolic blood pressure (SBP) on the risk of stroke in a large cohort of elderly patients with stage 3-5 CKD.

METHODS

We retrospectively identified 665 patients hospitalized in Beijing Friendship Hospital from January 2000 to December 2021. Patients were followed up until the occurrence of stroke or death. Multivariate logistic regression analysis and Cox proportional hazard models were used to analyze the risk factors for stroke according to the presence or absence of CKD. The association between CKD and stroke was further evaluated regarding the role of SBP in the hypertensive population.

RESULTS

In individuals with CKD, a J-shaped relationship was observed between SBP levels and the risk of stroke. Participants with CKD and an SBP less than 125 mmHg had a significantly higher cumulative stroke survival rate than those whose SBP was between 125 and 139 mmHg. The cumulative stroke survival rate increased progressively for those with SBP higher than 140 mmHg. This J-shaped relationship was not found in patients without CKD.

CONCLUSION

In elderly patients with CKD, those with the lowest BP are at increased risk for incident stroke. This phenomenon could be different from that in the general population.

Sleep apnea is associated with the increase of certain genera of Ruminococcaceae and Lachnospiraceae in the gut microbiome of hypertensive patients

BACKGROUND

Obstructive sleep apnea (OSA) and hypertension are interrelated diseases linked to gut dysbiosis. This study aimed to investigate the effect of OSA on the gut microbiome in the context of hypertension and vice versa.

RESEARCH DESIGN AND METHODS

Of 211 consecutively screened patients, 52 completed polysomnography study, medical history questionnaires, and fecal sample collection. 16S rRNA gene sequencing was performed on fecal samples, and diversity, richness, and microbial taxa were analyzed using bioinformatics.

RESULTS

Alpha diversity showed slightly decreased diversity in OSA and hypertension groups without significant difference, and the hypoxia burden index (HBI) showed a weak positive correlation with Chao1 index (r = 0.342, p < 0.05) in OSA patients. Firmicutes-to-Bacteroidetes ratio was higher in patients with than without OSA. In hypertensive patients, those with OSA had higher Ruminococcus_1, Lachnoclostridium, Lachnospira, [Ruminococcus]_torques_group, and unidentified Lachnospiraceae levels than those without OSA. Conversely, in OSA patients, hypertensive patients had lower Faecalibacterium and Lachnospiraceae_NK4A136_group levels.

CONCLUSION

The present study suggests a possible compensatory mechanism for gut microbiome changes in sleep apnea pathophysiology. The positive correlation between HBI and alpha diversity, and increase in certain genera of Ruminococcaceae and Lachnospiraceae in OSA patients may represent an adaptive response to hypoxia.

The Association Between Serum Complement 4 and Kidney Disease Progression in Idiopathic Membranous Nephropathy: A Multicenter Retrospective Cohort Study

Introduction

Complement system plays an important role in the pathogenesis of idiopathic membranous nephropathy (IMN), however, the relationship between serum complement 4 (C4) and kidney disease progression in IMN is unclear. This study aims to investigate the association of serum C4 level with the risk of kidney disease progression among patients with IMN.

Methods

The retrospective cohort assessed 1,254 participants with biopsy-proven IMN from three centers in Xi ‘an, Shaanxi Province, China. Baseline serum C4 levels were measured at renal biopsy. The association between baseline serum C4 and the risk of renal function progression, defined as a 30% decline in renal function or end stage renal disease, was evaluated in Cox proportional hazards models.

Results

A total of 328 patients with IMN and nephrotic proteinuria were eligible, and 11.3% (37/328) of them attained the renal function progression events after a median follow-up of 51 months (37-59 months). After adjustment for other confounders, a higher value of serum C4 was independently associated with a higher risk of renal function progression event with a hazard ratio (HR) of 4.76 (95% confidence interval [95% CI], 1.77-12.79) per natural log-transformed C4. In reference to the low level of C4, the adjusted HRs were 2.72 (95% CI, 1.02-7.24) and 3.65 (95% CI, 1.39-9.60), respectively, for the median and high levels of C4 (P for trend=0.008). Additionally, the results were robust and reliable in the sensitivity and subgroup analyses.

Conclusion

Among patients with IMN and nephrotic proteinuria, serum C4 at renal biopsy is an independent predictor for kidney disease progression regardless of other confounders.

Updates in hypertension: new trials, targets and ways of measuring blood pressure

PURPOSE OF REVIEW

Several recent trials and observational studies have identified critical areas that can help to improve the management and measurement of blood pressure in patients with hypertension.

RECENT FINDINGS

High-quality trial evidence supports intensive SBP lowering to 110-130 mmHg in older patients, potassium- based salt substitution in patients without chronic kidney disease, and chlorthalidone for the management of hypertension in patients with chronic kidney disease. In addition, population-based studies indicate enormous underdiagnosis of primary aldosteronism as well as greater sustained intensification of antihypertensive therapy in older patients by maximizing medication dosage rather than adding new agents. The prevalence of hypertension is stable worldwide, though is generally improving in high-income countries and worsening in low-income countries. Furthermore, although cuffless blood pressure devices have the potential to improve access to blood pressure measurement, they have not yet demonstrated sufficient accuracy for clinical use.

SUMMARY

Growing evidence supports intensive blood pressure lowering, sodium reduction, targeted antihypertensive treatment and appropriate screening for secondary hypertension to optimize blood pressure control and reduce the risk of target organ damage from hypertension. Future studies are needed to identify ways to improve our ability to implement these findings in routine clinical practice.

KDOQI US Commentary on the 2021 KDIGO Clinical Practice Guideline for the Management of Blood Pressure in CKD

The Kidney Disease Outcomes Quality Initiative (KDOQI) convened a work group to review the 2021 KDIGO (Kidney Disease: Improving Global Outcomes) guideline for the management of blood pressure in chronic kidney disease (CKD). This commentary is the product of that work group and presents the recommendations and practice points from the KDIGO guideline in the context of US clinical practice. A critical addition to the KDIGO guideline is the recommendation for accurate assessment of blood pressure using standardized office blood pressure measurement. In the general adult population with CKD, KDIGO recommends a goal systolic blood pressure less than 120 mm Hg on the basis of results from the Systolic Blood Pressure Intervention Trial (SPRINT) and secondary analyses of the Action to Control Cardiovascular Risk in Diabetes-Blood Pressure (ACCORD-BP) trial. The KDOQI work group agreed with most of the recommendations while highlighting the weak evidence base especially for patients with diabetes and advanced CKD.

Direct Determination rather than Oscillometric Estimation of Systolic Blood Pressure in Patients with Severe Chronic Kidney Disease

INTRODUCTION

Although arterial hypertension is a major concern in patients with chronic kidney disease (CKD), obtaining accurate systolic blood pressure (SBP) measurement is challenging in this population for whom automatic oscillometric devices may yield erroneous results.

METHODS

This cross-sectional study was conducted in 89 patients with stages 4, 5, and 5D CKD, for whom we compared SBP values obtained by the recently described systolic foot-to-apex time interval (SFATI) technique which provides direct SBP determination, the standard technique (Korotkoff sounds), and oscillometry. We investigated the effects of age, sex, diabetes, CKD stage, and pulse pressure to explain measurement errors defined as biases or misclassification relative to the SBP thresholds of 110-130-mm Hg.

RESULTS

All 3 techniques showed satisfactory reproducibility for SBP measurement (CCC > 0.84 and >0.91, respectively, in dialyzed and nondialyzed patients). The mean ± SD from SBP as determined via Korotkoff sounds was 1.7 ± 4.6 mm Hg for SFATI (CCC = 0.98) and 5.9 ± 9.3 mm Hg for oscillometry (CCC = 0.88). Referring to the 110-130-mm Hg SBP range outside which treatment prescription or adaptation is recommended for CKD patients, SFATI underestimated SBP in 3 patients and overestimated it in 1, whereas oscillometry underestimated SBP in 12 patients and overestimated it in 3. Higher pulse pressure was the main explanatory factor for measurement and classification errors.

DISCUSSION/CONCLUSION

SFATI provides accurate SBP measurements in patients with severe CKD and paves the way for the standardization of automated noninvasive blood pressure measurement devices. Before prescribing or adjusting antihypertensive therapy, physicians should be aware of the risk of misclassification when using oscillometry.

Effects of enhanced versus reduced vasodilating treatment on brachial and central blood pressure in patients with chronic kidney disease: a randomized controlled trial

BACKGROUND

Blood pressure (BP) control is important in chronic kidney disease (CKD), but a reduction in brachial BP may not mirror changes in central aortic BP (cBP) during antihypertensive medication. We hypothesize that a fall in cBP is better reflected during enhanced vasodilation treatment (EVT) compared with reduced vasodilation treatment (RVT) because of different hemodynamic actions of these interventions.

METHODS

Eighty-one hypertensive CKD stage 3-4 patients (mean measured glomerular filtration rate 36 ml/min per 1.73 m2) were randomized to either EVT based on renin--angiotensin blockade and/or amlodipine or RVT based on nonvasodilating β-blockade (metoprolol). Before randomization and following 18 months of treatment, we performed 24-h ambulatory BP measurements (ABPM) and radial artery pulse wave analysis for estimation of cBP and augmentation index (AIx). Forearm resistance (Rrest) was determined by venous occlusion plethysmography and arterial stiffness by carotid--femoral pulse wave velocity (PWV). Matched healthy controls were studied once for comparison.

RESULTS

Compared with controls, CKD patients had elevated ABPM, cBP and PWV. Although ABPM remained unchanged from baseline to follow-up in both treatment groups, cBP decreased 4.7/2.9 mmHg (systolic/diastolic) during EVT and increased 5.1/1.5 mmHg during RVT (Δ=9.8/4.4 mmHg, P=0.02 for SBP, P = 0.05 for DBP). At follow-up, the difference between systolic cBP and 24-h ABPM (ΔBPsyst) was negatively associated with heart rate and positively associated with AIx and Rrest (all P < 0.01) but not PWV (P = 0.32).

CONCLUSION

In CKD patients, EVT and RVT have opposite effects on cBP and the difference between cBP and ambulatory BP is larger for EVT than RVT.

Hypertension and the Kidney: Reduced Kidney Mass Is Bad for Both Normotensive and Hypertensive Rats

BACKGROUND

Hypertension is a leading cause of chronic kidney disease worldwide. Early studies demonstrated the short-term effects of hypertension on kidney function and morphology in ablative nephropathy. The aim of this study was to investigate the long-term consequences of hypertension in 5/6 nephrectomy (5/6NE) model.

METHODS

Reduction of the kidney mass by 5/6NE was created in spontaneous hypertensive rats (SHR) and genetically similar normotensive Wistar Kyoto (WKY) rats. Blood pressure, serum creatinine (SCr), hematuria, and proteinuria were monitored weekly for 23 weeks. Kidney morphology was assessed at the end of the study. Sham-operated rats from both strains were used as controls.

RESULTS

Rats with 5/6NE had increased SCr, blood pressure, hematuria, and proteinuria in both SHR and WKY. Even though the SCr levels and blood pressure were greater in 5/6NE SHR as compared with 5/6NE WKY rats, absolute changes from sham-operated rats were not statistically significant between these 2 groups. 5/6NE SHR had earlier onset and higher proteinuria than 5/6NE WKY rats. Hematuria was similar in 5/6NE SHR and 5/6NE WKY rats. However, 5/6NE SHR had enlarged glomeruli, increased interstitial fibrosis, and prominent intimal thickening in the small arteries/arterioles as compared with 5/6NE WKY rats.

CONCLUSIONS

The long-term severity of kidney injury correlated with higher blood pressure. Reduction of the kidney mass increases SCr, hematuria, proteinuria, and blood pressure in both normotensive and hypertensive rats. Histological assessment provides better information about underlying chronic kidney injury than actual changes in SCr and urinalysis.

Complement in Renal Disease as a Potential Contributor to Arterial Hypertension

OBJECTIVE

Complement deposition is prevalent in kidney biopsies of patients with arterial hypertension and hypertensive nephropathy, but an association of hypertension and complement deposition or involvement of complement in the pathogenesis of hypertensive nephropathy has not been shown to date.

METHODS

In this study, we analyzed complement C1q and C3c deposition in a rat model of overload and hypertension by subtotal nephrectomy (SNX) and in archival human renal biopsies from 217 patients with known hypertension and 91 control patients with no history of hypertension using semiquantitative scoring of C1q and C3c immunohistochemistry and correlation with parameters of renal function. To address whether complement was only passively deposited or actively expressed by renal cells, C1q and C3 mRNA expression were additionally analyzed.

RESULTS

Glomerular C1q and C3c complement deposition were significantly higher in kidneys of hypertensive SNX rats and hypertensive compared to nonhypertensive patients. Mean arterial blood pressure (BP) in SNX rats correlated well with the amount of glomerular C1q and C3c deposition and with left ventricular weight, as an indirect parameter of high BP. Quantitative mRNA analysis showed that C3 was not only deposited but also actively produced by glomerular cells of hypertensive SNX rats and in human renal biopsies. Of note, in patients CKD-stage correlated significantly with the intensity of glomerular C3c staining, but not with that of C1q.

CONCLUSION

Renal complement deposition correlated with experimental hypertension as well as the presence of hypertension in a variety of renal diseases. To answer the question, if and how exactly renal complement is causative for the pathogenesis of arterial hypertension in men, further studies are needed.

The Association of Orthostatic Hypotension With Ambulatory Blood Pressure Phenotypes in SPRINT

BACKGROUND

Clinic blood pressure (BP) when measured in the seated position, can miss meaningful BP phenotypes, including low ambulatory BP (white coat effects [WCE]) or high supine BP (nocturnal non-dipping). Orthostatic hypotension (OH) measured using both seated (or supine) and standing BP, could identify phenotypes poorly captured by seated clinic BP alone.

METHODS

We examined the association of OH with WCE and night-to-daytime systolic BP (SBP) in a subpopulation of SPRINT, a randomized trial testing the effects of intensive or standard (<120 vs. <140 mm Hg) SBP treatment strategies in adults at increased risk of cardiovascular disease. OH was assessed during follow-up (6, 12, and 24 months) and defined as a decrease in mean seated SBP ≥20 or diastolic BP ≥10 mm Hg after 1 min of standing. WCE, based on 24-hour ambulatory BP monitoring performed at 27 months, was defined as the difference between 27-month seated clinic and daytime ambulatory BP ≥20/≥10 mm Hg. Reverse dipping was defined as a ratio of night-to-daytime SBP >1.

RESULTS

Of 897 adults (mean age 71.5±9.5 years, 29% female, 28% black), 128 had OH at least once. Among those with OH, 15% had WCE (vs. 7% without OH). Moreover, 25% of those with OH demonstrated a non-dipping pattern (vs. 14% without OH). OH was positively associated with both WCE (OR=2.24; 95%CI: 1.28, 4.27) and reverse dipping (OR=2.29; 95% CI: 1.31, 3.99).

CONCLUSIONS

The identification of OH in clinic was associated with two BP phenotypes often missed with traditional seated BP assessments. Further studies on mechanisms of these relationships are needed.

CLINICAL TRIALS REGISTRATION

Trial Number NCT03569020.