Twenty-four-hour blood pressure profile and blood pressure variability in untreated hypertension and during antihypertensive treatment by once-a-day nadolol

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.

BLOOD PRESSURE VARIABILITY IN PATIENTS WITH BRANCH RETINAL VEIN OCCLUSION

PURPOSE

To evaluate short-term blood pressure variability over 24 hours in patients with branch retinal vein occlusion (BRVO) versus controls.

METHODS

A sample of 80 patients with BRVO (i.e., Group 1) and 75 controls (i.e., Group 2) was formed for a prospective, cross-sectional, comparative, case-control study. In a 24-hour period, each participant's blood pressure was measured by ambulatory monitoring every 15 minutes during the day and every 30 minutes at night. Mean values of systolic blood pressure (SBP), diastolic blood pressure (DBP), arterial blood pressure (ABP), and a variability index recorded during the day, at night, and throughout the 24-hour period were subjected to statistical analyses.

RESULTS

Mean daytime, night-time, and 24-hour SBP, DBP, and ABP values did not significantly differ between the groups. However, mean variability index values of daytime, night-time, and 24-hour SBP, DBP, and ABP significantly increased in patients with BRVO versus controls. Multivariate logistic regression analyses revealed that 24-hour blood pressure variability in each of SBP, DBP, and ABP was an independent determinant of BRVO.

CONCLUSION

Because the daytime, night-time, and 24-hour blood pressure variability in SBP, DBP, and ABP was significantly greater among patients with BRVO than among controls, blood pressure variability could factor into the pathogenesis of BRVO.

Methodology and technology for peripheral and central blood pressure and blood pressure variability measurement: current status and future directions - Position statement of the European Society of Hypertension Working Group on blood pressure monitoring and cardiovascular variability

Office blood pressure measurement has been the basis for hypertension evaluation for almost a century. However, the evaluation of blood pressure out of the office using ambulatory or self-home monitoring is now strongly recommended for the accurate diagnosis in many, if not all, cases with suspected hypertension. Moreover, there is evidence that the variability of blood pressure might offer prognostic information that is independent of the average blood pressure level. Recently, advancement in technology has provided noninvasive evaluation of central (aortic) blood pressure, which might have attributes that are additive to the conventional brachial blood pressure measurement. This position statement, developed by international experts, deals with key research and practical issues in regard to peripheral blood pressure measurement (office, home, and ambulatory), blood pressure variability, and central blood pressure measurement. The objective is to present current achievements, identify gaps in knowledge and issues concerning clinical application, and present relevant research questions and directions to investigators and manufacturers for future research and development (primary goal).

Blood pressure variability: assessment, predictive value, and potential as a therapeutic target

A large body of evidence has consistently supported the relationship between blood pressure (BP) levels and the risk of cardiovascular complications. In recent years, several independent studies have also indicated that this risk may not only depend on the magnitude of the blood pressure elevation per se but also on the presence of other associated conditions such as increased blood pressure variability. This concept has been supported by a series of reports, most of which post hoc analyses of clinical trials in hypertension, showing that increasing values of BP variability (BPV) (either in the short term, in the midterm, or in the long term) may predict development, progression, and severity of cardiac, vascular, and renal organ damage, as well as cardiovascular events and mortality. Remarkably, studies conducted in populations at high cardiovascular risk have shown increasing values of BPV in the individual subjects (so-called intra- or within-individual BPV) to be strong predictors of cardiovascular morbidity and mortality, even to a larger extent than average BP values. However, in subjects at low to moderate cardiovascular risk, the contribution of BPV to cardiovascular risk prediction over and beyond average BP values has been shown to be only moderate. The aim of this paper is to critically review the evidence addressing the prognostic relevance of different components of BPV addressing a yet open question, i.e., whether routine assessment of BPV in clinical practice should be regarded as an additional target of antihypertensive treatment to improve cardiovascular protection.

Assessment and interpretation of blood pressure variability in a clinical setting

Blood pressure (BP) is characterized by marked fluctuations occurring within the 24 h as a result of complex interactions between behavioral, environmental, humoral, and neural central or reflex influences. Significant BP variations also occur over more prolonged periods of time (i.e. between days, weeks, months, seasons and even years), not as a random phenomenon but as a result of several interacting factors yet not completely identified. Depending on the method and time interval considered for measurement, the clinical significance and prognostic implications of different types of BP variability (BPV) may substantially differ. Either in the short or in the long term, BPV has been associated with development, progression and severity of cardiac, vascular and renal organ damage and with an increased risk of cardiovascular events and mortality, independently adding to cardiovascular risk, over and above the contribution of elevated mean BP levels. The present paper provides a review on the main methods currently employed for assessment of BPV as well as on the mechanisms, clinical interpretation and prognostic significance of different types of BPV, addressing the question on whether BPV should be a target for antihypertensive treatment for the current prevention of cardiovascular disease.

Assessment and management of blood-pressure variability

Blood pressure (BP) is characterized by marked short-term fluctuations occurring within a 24 h period (beat-to-beat, minute-to-minute, hour-to-hour, and day-to-night changes) and also by long-term fluctuations occurring over more-prolonged periods of time (days, weeks, months, seasons, and even years). Rather than representing 'background noise' or a randomly occurring phenomenon, these variations have been shown to be the result of complex interactions between extrinsic environmental and behavioural factors and intrinsic cardiovascular regulatory mechanisms. Although the adverse cardiovascular consequences of hypertension largely depend on absolute BP values, evidence from observational studies and post-hoc analyses of data from clinical trials have indicated that these outcomes might also depend on increased BP variability (BPV). Increased short-term and long-term BPV are associated with the development, progression, and severity of cardiac, vascular, and renal damage and with an increased risk of cardiovascular events and mortality. Of particular interest are the findings from post-hoc analyses of large intervention trials in hypertension, showing that within-patient visit-to-visit BPV is strongly prognostic for cardiovascular morbidity and mortality. This result has prompted discussion on whether antihypertensive treatment should be targeted not only towards reducing mean BP levels but also to stabilizing BPV with the aim of achieving consistent BP control over time, which might favour cardiovascular protection.

24 h sequential spectral analysis of arterial blood pressure and pulse interval in free-moving subjects

A procedure for the 24 h tracking of the 0.25, 0.1, and 0.05 Hz oscillations in blood pressure (BP) and pulse interval (PI) in ambulant subjects has been developed. It includes: 1) sampling of a 24 h intra-arterial BP recording, extraction of the systolic (S) and diastolic (D) BP and PI from each heart beat followed by storage into separate series; 2) high-pass filtering and a splitting of each series into consecutive records of 256 values; 3) estimation of power spectral density (PSD) via FFT in each stationary record, and finally, computation of the power of each target oscillation. Using this procedure we analyzed data from ten hospitalized free-moving subjects in whom BP was recorded by the Oxford technique. The results revealed different patterns of the 0.25, 0.1, and 0.05 oscillations over the day-night cycle, showing a differentiated involvement during the 24 h of the mechanisms responsible for such rhythmic phenomena. Moreover, in order to reinforce the meaning of the obtained results and to exclude the possible negative effects due to the drawbacks typical of the FFT algorithm, we also performed a second spectral estimate based on the AR modeling. The obtained results validates the FFT approach.