Ambulatory blood pressure monitoring and morning surge in blood pressure in adult black and white South Africans

We examined whether there were differences in the circadian variation in blood pressure and the morning surge in blood pressure between black and white Africans. Clinic and ambulatory blood pressure data obtained from the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study was examined (n = 406; 49% black African). Ambulatory blood pressure readings were fitted to a six-parameter double logistic equation to determine the power and rate of the morning surge in blood pressure. Multiple linear regression analysis was used to examine differences in blood pressure between black and white participants. Clinic and ambulatory blood pressure were higher in black participants throughout the day and night. In those taking medications, blood pressure was less well controlled in black subjects. Despite the higher systolic blood pressure, the day-night difference estimated by the logistic function was similar in black and white participants. However, the rate of rise and power in the morning surge in blood pressure was lower in black participants. We conclude that black participants of the SABPA study present with higher blood pressure throughout the day and night but have a lower power of the morning surge in blood pressure due to a slower morning rate of increase. Moreover, they had an increased prevalence of undiagnosed hypertension and, in those taking medication, were less likely to have their blood pressure controlled than their white counterparts

Wisdom of the crowd: insights gained from comparing predicted and observed effects of blood pressure lowering strategies

In a first of its kind assessment in cardiovascular research, we assessed whether pooled cardiovascular expertise could accurately predict efficacy and tolerability for both a novel and an established treatment option. A survey was administered prior to the publication of the QUARTET (A Quadruple UltrA-low-dose tReatment for hypErTension) trial. QUARTET was a multicentre, double-blind, parallel-group, trial that randomised participants to initial treatment with either monotherapy or an ultra-low dose quadruple single pill combination for 12 weeks. Survey participants were asked to predict blood pressure (BP) at 12 weeks and 52 weeks for both groups

May Measurement Month 2019: an analysis of blood pressure screening results from Australia.

May Measurement Month (MMM) is an annual global blood pressure (BP) screening campaign aimed at obtaining standardized BP measurements and other relevant health information from members of the community to increase awareness of elevated BP and the associated risks. Adults (≥18 years) were recruited through opportunistic sampling across the various Australian states during May 2019. Three BP readings were recorded in a standardized manner for each participant, and data on lifestyle factors and comorbidities were collected. Hypertension was defined as a systolic BP ≥140 mmHg, or a diastolic BP ≥90 mmHg (according to the MMM protocol) or taking antihypertensive medication. Multiple imputation was used to estimate participants' mean BP where three readings were not available. Of the 2877 participants, 901 (31.3%) had hypertension of whom 455 (50.5%) were aware of their condition, and 366 (40.6%) were on antihypertensive medication. Of those taking antihypertensive medication, 54.3% were controlled to <140/90 mmHg with the remaining 45.7% of participants inadequately treated. Approximately 74% of treated patients were on a single antihypertensive medication. The MMM campaign provides an important platform for standardized compilation of BP data and creation of BP awareness in Australia and other nations worldwide. Data from the 2019 MMM campaign highlight that BP control rates in Australia remain unacceptably low

May Measurement Month: results of 12 national blood pressure screening programmes between 2017 and 2019

The first May Measurement Month (MMM) campaign, a global blood pressure (BP) screening programme, began in 2017 as an initiative of the International Society of Hypertension.1 Two subsequent annual campaigns have also been completed in consecutive years2,3 and having had to defer activities due to the COVID-19 pandemic in 2020 the fourth campaign was run in 2021, the results of which are currently in press. Since its initiation in 2017, volunteers from more than 100 countries have participated. The aims of MMM have remained consistent from the start—to raise awareness of the importance of the measurement of BP at the individual and population level and to provide a temporary pragmatic solution to the shortfall in BP screening programmes in countries around the world

Delayed retinal vein recovery responses indicate both non-adaptation to stress as well as increased risk for stroke: the SABPA study

OBJECTIVES: Low or high sympatho-adrenal-medullary axis (SAM) and hypothalamic-pituitary-adrenal axis (HPA) dysregulation reflect chronic stress. Retinal vessel dynamics may relate to SAM, HPA activity and stroke risk. Our objectives were therefore to assess the relationships between retinal vessel, SAM and HPA responses, and to determine stroke risk. METHODS: A prospective bi-ethnic gender cohort (n = 275, 45 ± 9 years) was included. Urine/serum/saliva samples for SAM [norepinephrine:creatinine ratio (u-NE)] and HPA [adrenocorticotrophic hormone (ACTH), cortisol] were obtained at baseline, three-year follow up and upon flicker light-induced provocation. Diastolic ocular perfusion pressure was measured as a marker of hypo-perfusion. Retinal arterial narrowing and venous widening calibres were quantified from digital images in the mydriatic eye. A validated stress and stroke risk score was applied. RESULTS: An interaction term was fitted for venous dilation in u-NE tertiles (p ≤ 0.05) and not in u-NE median/quartiles/quintiles. Independent of race or gender, tertile 1 (low u-NE) had a 112% increase in u-NE, decreases in cortisol, and no changes in ACTH over three years (positive feedback). Tertile 3 (high u-NE) contradictorily had decreases in u-NE and cortisol, and increases in ACTH (negative feedback). In tertile 1, reduced arterial dilation, and faster arterial vasoconstriction and narrowing were related to higher SAM activity and hypo-perfusion (p ≤ 0.05), whereas delayed venous dilation, recovery and widening were related to cortisol hypo-secretion (p ≤ 0.05). In tertile 1, delayed venous recovery responses predicted stress and stroke risk [odds ratio 4.8 (1.2-19.6); p = 0.03]. These associations were not found in u-NE tertiles 2 and 3. CONCLUSIONS: In response to low norepinephrine, a reflex increase in SAM activity occurred, enhancing arterial vasoconstriction and hypo-perfusion. Concomitant HPA dysregulation attenuated retinal vein vasoactivity and tone, reflecting delayed vein recovery responses and non-adaptation to stress. These constrained vein recovery responses are indicative of increased chronic stress and stroke risk

Blood pressure screening during the May Measurement Month 2017 programme in Vietnam-South-East Asia and Australasia.

Elevated blood pressure (BP) is a growing burden worldwide, leading to over 10 million deaths each year. May Measurement Month (MMM) is a global initiative aimed at raising awareness of high BP and to act as a temporary solution to the lack of screening programmes worldwide. Our aim was to screen for hypertension (HTN) and cardiovascular risk factors in people aged ≥18 years in the community, thereby define the proportion of subjects with elevated BP and assess the awareness and the effectiveness of its treatment. An opportunistic cross-sectional survey of volunteers aged ≥18 years was carried out in May 2017. Blood pressure measurement, the definition of HTN and statistical analysis followed the standard MMM protocol. From May 2017 to June 2017, through 10 cities/provinces in Vietnam, 10 993 individuals with mean age 49.1 ± 16.2 years were screened during MMM17. After multiple imputation, 3154 (28.7%) had HTN. Of individuals not receiving antihypertensive medication, 1509 (16.1%) were hypertensive. Of individuals receiving antihypertensive medication, 620 (37.7%) had uncontrolled BP. Raised BP was also associated with additional risk factors including smoking, alcohol, overweight-obesity, and diabetes. May Measurement Month 17 was the largest BP screening campaign ever undertaken in Vietnam. Undiagnosed and uncontrolled HTN in Vietnam remains a substantial health problem. Local campaigns applying standardized methods such as MMM17, will be highly useful to screen for the significant number of individuals with raised BP and increase the awareness of HTN

Sympatho-renal axis in chronic disease

Essential hypertension, insulin resistance, heart failure, congestion, diuretic resistance, and functional renal disease are all characterized by excessive central sympathetic drive. The contribution of the kidney’s somatic afferent nerves, as an underlying cause of elevated central sympathetic drive, and the consequences of excessive efferent sympathetic signals to the kidney itself, as well as other organs, identify the renal sympathetic nerves as a uniquely logical therapeutic target for diseases linked by excessive central sympathetic drive. Clinical studies of renal denervation in patients with resistant hypertension using an endovascular radiofrequency ablation methodology have exposed the sympathetic link between these conditions. Renal denervation could be expected to simultaneously affect blood pressure, insulin resistance, sleep disorders, congestion in heart failure, cardiorenal syndrome and diuretic resistance. The striking epidemiologic evidence for coexistence of these disorders suggests common causal pathways. Chronic activation of the sympathetic nervous system has been associated with components of the metabolic syndrome, such as blood pressure elevation, obesity, dyslipidemia, and impaired fasting glucose with hyperinsulinemia. Over 50% of patients with essential hypertension are hyperinsulinemic, regardless of whether they are untreated or in a stable program of treatment. Insulin resistance is related to sympathetic drive via a bidirectional mechanism. In this manuscript, we review the data that suggests that selective impairment of renal somatic afferent and sympathetic efferent nerves in patients with resistant hypertension both reduces markers of central sympathetic drive and favorably impacts diseases linked through central sympathetics—insulin resistance, heart failure, congestion, diuretic resistance, and cardiorenal disorders

Sympathetic Activation and Baroreflex Function during Intradialytic Hypertensive Episodes

BACKGROUND: The mechanisms of intradialytic increases in blood pressure are not well defined. The present study was undertaken to assess the role of autonomic nervous system activation during intradialytic hypertensive episodes. METHODOLOGY/PRINCIPAL FINDINGS: Continuous interbeat intervals (IBI) and systolic blood pressure (SBP) were monitored during hemodialysis in 108 chronic patients. Intradialytic hypertensive episodes defined as a period of at least 10 mmHg increase in SBP between the beginning and the end of a dialysis session or hypertension resistant to ultrafiltration occurring during or immediately after the dialysis procedure, were detected in 62 out of 113 hemodialysis sessions. SBP variability, IBI variability and baroreceptor sensitivity (BRS) in the low (LF) and high (HF) frequency ranges were assessed using the complex demodulation technique (CDM). Intradialytic hypertensive episodes were associated with an increased (n = 45) or decreased (n = 17) heart rate. The maximal blood pressure was similar in both groups. In patients with increased heart rate the increase in blood pressure was associated with marked increases in SBP and IBI variability, with suppressed BRS indices and enhanced sympatho-vagal balance. In contrast, in those with decreased heart rate, there were no significant changes in the above parameters. End-of-dialysis blood pressure in all sessions associated with hypertensive episode was significantly higher than in those without such episodes. In logistic regression analysis, predialysis BRS in the low frequency range was found to be the main predictor of intradialytic hypertension. CONCLUSION/SIGNIFICANCE: Our data point to sympathetic overactivity with feed-forward blood pressure enhancement as an important mechanism of intradialytic hypertension in a significant proportion of patients. The triggers of increased sympathetic activity during hemodialysis remain to be determined. Intradialytic hypertensive episodes are associated with higher end-of-dialysis blood pressure, suggesting that intradialytic hypertension may play a role in generation of interdialytic hypertension