Renal dysfunction impairs circadian variation of endothelial function in patients with essential hypertension

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.

Soluble Urokinase-Type Plasminogen Activator Receptor, Changes of 24-Hour Blood Pressure, and Progression of Chronic Kidney Disease

Background

Soluble urokinase‐type plasminogen activator receptor (suPAR) is associated with cardiovascular risks and poor renal outcomes. However, whether elevated suPAR levels are associated with 24‐hour blood pressure patterns or kidney disease progression in patients with chronic kidney disease (CKD) is unclear.

Methods and Results

A total of 751 patients with CKD stage 1 to 5 were recruited from CMERC‐HI (Cardiovascular and Metabolic Disease Etiology Research Center–High Risk) cohort study (2013–2018). The relationship of serum suPAR levels to 24‐hour blood pressure parameters and CKD progression was analyzed. The median serum suPAR level was 1439.0 (interquartile range, 1026.2–2150.1) pg/mL, and the mean estimated glomerular filtration rate was 52.8±28.5 mL/min per 1.73 m² at baseline. Patients with higher suPAR levels had significantly higher levels of office, 24‐hour, daytime, and nighttime systolic blood pressure and nighttime diastolic blood pressure than those with lower suPAR levels. The highest suPAR tertile was associated with an increased risk of a reverse dipping pattern (odds ratio, 2.93; 95% CI, 1.27–6.76; P=0.01). During a follow‐up of 43.2 (interquartile range, 27.0–55.6) months, the CKD progression occurred in 271 (36.1%) patients. The highest suPAR tertile was significantly associated with higher risk of CKD progression than the lowest tertile (hazard ratio [HR], 2.09; 95% CI, 1.37–3.21; P=0.001). When the relationship was reevaluated with respect to each dipping pattern (dipper, extreme dipper, nondipper, and reverse dipper), this association was consistent only in reverse dippers in whom the risk of CKD progression increased (HR, 1.43; 95% CI, 1.02–2.01; P=0.03) with every 1‐unit increase in serum suPAR levels.

Conclusions

Elevated suPAR levels are independently associated with CKD progression, and this association is prominent in reverse dippers.

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.