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BACKGROUND A lower heart rate (HR) increases left ventricular (LV) ejection volume. Whether this contributes to the adverse effects of HR on central pulse pressure (PPc) through reservoir volume effects is uncertain. METHODS Using noninvasive central pressure, aortic velocity, and diameter measurements in the outflow tract (echocardiography), we assessed the role of LV ejection volume as a determinant of HR relations with PPc in 824 community participants. RESULTS A lower HR was independently associated with both stroke volume (SV) (P < 0.001) and a shift in ejection volume from early (until the first systolic shoulder) to late (from first systolic shoulder to peak PP) systole (P < 0.05 to P < 0.005). Adjustments for LV end diastolic volume markedly diminished HR relations with SV and indexes of the shift in ejection volume to late systole. A lower HR was also independently associated with increases in forward traveling pressure waves (Pf) and PPc (P < 0.0001). However, adjustments for neither SV, nor indexes of a shift in ejection volume to late systole modified HR-Pf or PPc relations. This was despite relationships between indexes of a shift in ejection volume to late systole and both Pf and PPc (P < 0.0001). In contrast, adjustments for the increases in re-reflected and backward traveling wave pressures with a lower HR, eliminated HR-Pf and PPc relations. CONCLUSIONS In contrast to current thought, a lower HR is not associated with increases in PPc through an impact of increases in late systolic ejection volume on aortic reservoir volume, but rather through increases in backward wave pressures.

Background: Whether systolic blood pressure (SBP) control in sustained volume-dependent primary hypertension is associated with blunted ANP (atrial natriuretic peptide) relationships with indexes of volume load is unknown. Methods: Systemic hemodynamics (central pressure, echocardiographic aortic velocity and diameter measurements in the outflow tract), circulating ANP concentrations (ELISA assays) and glomerular and tubular function (24-hour urine collections [n=519]) were determined in a community of African ancestry (n=772). Results: As compared with those with a controlled SBP, those with an uncontrolled SBP (n=198) showed lower ANP concentrations ( P P + excretion (FeNa + ; P P P P P P >0.25), cardiac output ( P >0.29), FeNa + ( P >0.77), or glomerular filtration rate ( P >0.47) and ANP concentrations were noted. Furthermore, in those with an uncontrolled SBP, no relationships between ANP concentrations and SVR or Zc were observed ( P >0.34). Conclusions: In a population where primary hypertension is strongly volume-dependent, those with an uncontrolled SBP have an attenuated relationship between ANP and both renal and hemodynamic indexes of volume overload and the vascular effects of ANP.

AIMS Whether renal mechanisms of hypertension primarily translate into increases in systemic vascular resistance (SVR) in all populations is uncertain. We determined whether renal mechanisms associate with either increases in SVR (and impedance to flow) or systemic flow in a community of African ancestry. METHOD In a South African community sampled across the full adult age range (n = 546), we assessed stroke volume (SV), peak aortic flow (Q), SVR, characteristic impedance (Zc) and total arterial compliance (TAC) from velocity and diameter measurements in the outflow tract (echocardiography) and central arterial pressures. Renal changes were determined from creatinine clearance (glomerular filtration rate, GFR) and fractional Na+ excretion (FeNa+) (derived from 24-h urine collections). RESULTS Independent of confounders (including MAP and pressures generated by the product of Q and Zc), SV (and hence cardiac output) (P

Although hypertension in groups of African ancestry is volume-dependent, the relative impact of systemic flow (stroke volume, peak aortic flow [Q]) versus vascular mechanisms (systemic vascular resistance, aortic characteristic impedance [Zc], total arterial compliance) components of arterial load has not been evaluated across the adult age range. In participants of African ancestry (n=824, age=16–99 years, 68.3% female), using central arterial pressure and aortic velocity and diameter measurements in the outflow tract, we determined the hemodynamic correlates of age-related increases in blood pressure. Strong independent positive relations between age and stroke volume or peak aortic Q were noted ( P P P P P P

The relative contribution of loading conditions at different ages across the full adult lifespan to decreases in left ventricular (LV) diastolic function is unclear. Using central arterial pressure and aortic velocity and diameter measurements in the outflow tract, we determined the contribution of systemic vascular resistance, compression wave pressures (characteristic impedance [Zc]×aortic flow [Q], [P Q×Zc ]) and backward wave pressures (Pb) to LV diastolic function (echocardiography) in a community sample across the full adult lifespan (n=605). Starting from early adulthood, stepwise age-related increases in LV filling pressures (E/e’) and decreases in myocardial relaxation (e’) were noted ( P Q×Zc positively correlates with age, Pb, but not systemic vascular resistance was independently associated with LV mass index ( P P P Q×Zc positively correlates with age, again Pb, but neither P QxZc nor systemic vascular resistance was independently associated with LV mass index ( P P P

Alterations in sodium (Na + ) relative to potassium (K + ) intake increase systolic blood pressure, effects in-part attributed to enhanced pulsatile loads (pulse pressure) beyond steady-state pressures (mean arterial pressure). Whether this effect is through reversible changes (increases in blood volume and hence aortic flow [Q] or wave reflection [Pb]), or potentially irreversible structural changes in the proximal aorta, is unknown. In 581 black South Africans, we determined 24-hour urinary Na + and K + excretion and aortic function from central aortic pressure (radial pulse wave analysis [SphygmoCor software]), velocity, and diameter measurements. Proximal aortic function was assessed from characteristic impedance (Zc). Beyond mean arterial pressure and additional confounders, urinary Na + /K + was independently associated with Zc ( P P =0.30) or alternative aspects of Q or ejection volume. Although age was strongly associated with proximal aortic diameter, no independent relations between urinary Na + /K + and aortic diameter were noted ( P =0.17). Relations between urinary Na + /K + and Zc translated into independent relations with early systolic compression wave pressures (QxZc [P QxZc ]) and aortic forward wave pressures but not Pb. Moreover, neither reflected wave magnitude ( P =0.92) nor aortic pulse wave velocity were independently associated with urinary Na + /K + . In product of coefficient mediation analysis, the independent relations between urinary Na + /K + and peak aortic or brachial pulse pressure or systolic blood pressure were accounted for by Zc and P QxZc . In conclusion, abnormalities in Na + /K + intake determine pulse pressure or systolic blood pressure beyond mean arterial pressure mainly through potentially irreversible impacts on proximal aortic impedance rather than readily modifiable increases in aortic flow (blood volume) or wave reflection.

Although peak aortic flow (Q) is now recognized as a major determinant of hypertension in Africa, current therapy has no proven ability to target this change. The mechanisms of this effect, therefore, require elucidation. We compared the intrafamilial aggregation and heritability of Q to that of the vascular determinants of pulse pressure (PP) and SBP in Africa.The intrafamilial aggregation and heritability of Q and aortic characteristic impedance (Zc) or total arterial compliance (TAC) was determined in 669 participants of 194 families (69 father-mother, 385 parent-child, 157 sibling-sibling pairs) in a community in Africa with prevalent flow-dependent primary hypertension. Haemodynamics were determined from velocity and diameter measurements in the outflow tract (echocardiography) and central arterial pressures.No mother-father correlations were noted for either Q or Zc. However, with adjustments for confounders, parent-child (P 0.0001) and sibling-sibling (P 0.0001) correlations were noted for Q. Parent-child and/or sibling-sibling correlations were also noted for Zc or TAC but were weaker for Zc and mother-father correlations were noted for TAC. Moreover, Q showed markedly stronger multivariate adjusted heritability estimates (h2 = 0.82 ± 0.07, P 0.0001) than Zc (h2 = 0.44 ± 0.10, P 0.0001)(P 0.005 for comparisons) and TAC (h2 = 0.47 ± 0.08, P 0.0001)(P 0.005 for comparisons). Importantly, the heritability of Q was also greater than that for PP (h2 = 0.12 ± 0.09, P = 0.11) (P 0.0001 for comparisons), or SBP (h2 = 0.13 ± 0.10, P = 0.08) (P 0.0001 for comparisons).Of the haemodynamic determinants of SBP, peak aortic flow is the most strongly inherited in Africa. Peak aortic flow, therefore, represents an important target for identifying novel therapeutic approaches to controlling SBP in Africa.

Through both backward (Pb) and forward (Pf) wave effects, a lower heart rate (HR) associates with increased central (PPc), beyond brachial pulse pressure (PP). However, the relative contribution to Pf of aortic flow (Q) versus re-reflection of Pb, has not been determined. Using central pressure, aortic velocity and diameter measurements in the outflow tract (echocardiography), we constructed central pressure waveforms that account for the relative contribution of Q versus re-reflection to Pf. We thus evaluated the mechanisms of HR-PPc relations in a community sample (n=824) and the impact of age thereon. Inverse HR-PPc ( P P =0.064) relations were noted. The slope of HR-PPc relation was increased in older adults ( P P P P P P

AIMS To determine whether the confounding influence of stroke work on left ventricular mass (LVM) limits the ability of LVM to detect hypertensive LV dysfunction in systemic flow-dependent hypertension. METHODS In a community with prevalent systemic flow-dependent hypertension (n = 709), arterial haemodynamics, LVM and LV function were determined using central arterial pressure, aortic velocity and diameter measurements in the outflow tract, and echocardiography with tissue Doppler imaging. RESULTS In multivariate models, stroke work showed markedly stronger relations with LVM index (LVMI) than blood pressure load [central arterial SBP (SBPc), backward wave pressure (Pb), 24-h SBP] (P

BACKGROUND Whether in volume-dependent primary hypertension, concentric left ventricular (LV) remodeling beyond hypertrophy (LVH) represents the impact of a pressure rather than a volume overload, is unclear. METHODS Using central arterial pressure, and aortic velocity and diameter measurements in the outflow tract (echocardiography), we determined the factors that associate with concentric LVH or remodeling in a community of African ancestry (n = 709) with prevalent volume-dependent primary hypertension. RESULTS Both left ventricular mass index (LVMI) and relative wall thickness (RWT) were positively and independently associated with end diastolic volume (EDV), stroke volume (SV), and peak aortic flow (Q) (P < 0.05 to CONCLUSIONS In volume-dependent primary hypertension, concentric LVH is determined as much by volume-dependent increases in systemic flow and an enhanced BP as eccentric LVH. Concentric remodeling nevertheless reflects decreases in systolic function beyond LVH.

AIM We aimed to determine whether the impact of aortic stiffness on atherosclerotic or small vessel end organ damage beyond brachial blood pressure depends in-part on stiffness-induced increases in central arterial pressures produced by an enhanced resistance to flow (characteristic impedance, Zc). METHODS We studied 1021 participants, 287 with stroke or critical limb ischaemia, and 734 from a community sample with atherosclerotic or small vessel end organ measures. Central arterial haemodynamics were determined from arterial pressure (SphygmoCor) and velocity and diameter assessments in the outflow tract (echocardiography). RESULTS Although Zc and carotid-femoral pulse wave velocity (PWV) were correlated (P

AIMS Age-related increases in systemic blood flow [stroke volume (SV), cardiac output (CO), and aortic flow (Q)] contribute substantially to untreated or inadequately controlled (uncontrolled) blood pressure (BP) in Africa. We aimed to identify the haemodynamic determinants of uncontrolled systolic--diastolic (Syst--diast HT) versus uncontrolled isolated systolic (ISH) or diastolic (IDH) hypertension. METHODS Using central arterial pressure and aortic outflow tract velocity and diameter measurements (echocardiography), the haemodynamic correlates of BP were determined in 725 community participants of African ancestry (19.6% uncontrolled Syst--diast HT, 9.2% uncontrolled ISH, 11.3% uncontrolled IDH). RESULTS Independent of confounders, compared with those with a normotensive BP, those with uncontrolled Syst--diast HT had increases in SV, CO, Q, systemic vascular resistance (SVR) and aortic characteristic impedance (Zc) and decreases in total arterial compliance (TAC) (P

Alterations in sodium (Na

Introduction Overweight and obesity have become the fifth leading risk for global deaths. Office employees have been identified as a high risk group due to the sedentary nature of their work, and accurate weight perception is believed to be critical to acceptance of weight control interventions. This study was conducted to assess the nutritional status, weight perception and weight control practices of office employees in Sokoto, Nigeria. Methods A cross sectional study was conducted among 285 randomly selected office employees in private establishments in Sokoto, Nigeria, in February and March 2013. Anthropometry was done for the participants in addition to questionnaire administration. Results The mean age of the participants was 33.08 ± 7.23 years, they were predominantly males (56.5%) and married (57.5%). None was underweight, 111 (38.9%) had normal weight, 105 (36.8%) were overweight and 69 (24.2%) were obese. Among the participants with normal weight, overweight and obesity, 71.2%, 35.2% and 58.0% respectively accurately perceived their weight; while 28.8%, 50.5% and 30.4% respectively underestimated their weight. There was poor agreement between actual and perceived weight (k statistics = 0.341, p < 0.001). Only 67 (23.5%) of the 285 participants were engaged in weight control practices. Conclusion This study showed high prevalence of overweight and obesity, weight misperceptions, and poor uptake of weight control practices among office employees in Sokoto, Nigeria. These findings underscore the need for a holistic approach to obesity control interventions that encompasses both body image perception and nutritional assessment.

Background: Anaemia in pregnancy remains a common problem affecting women in northern Nigeria. It is associated with several adverse consequences.Objective: The aim of this study was to determine the prevalence of anaemia and its associated factors among pregnant women in Koko/Besse local government area of Kebbi state,Northwest Nigeria.Methodology: A cross-sectional study was conducted among women using a standardized questionnaire for data collection. Haematocrit level was determined using the centrifuge technique. Data was analysed descriptively in Statistical Package for Social Sciences (SPSS).Results: The prevalence of anaemia among our respondents was 23.5%.There were higher prevalence rates among those married in monogamous families, who did not attend antenatal care, unemployed, and those who were non-compliant with their prescribed antenatal care haematinics.Conclusion: The prevalence of anaemia in pregnancy even though high, was relatively lower than findings from other studies in the sub-region.A well developed and implemented public health intervention is likely to further reduce this prevalence.Keywords: Anaemia, pregnancy, prevalence, associated factors, Koko, Kebbi

Aortic pulse wave velocity (PWV) and backward waves, as determined from wave separation analysis, predict cardiovascular events beyond brachial blood pressure. However, the extent to which these aortic hemodynamic variables contribute independent of each other is uncertain. In 749 randomly selected participants of African ancestry, we therefore assessed the extent to which relationships between aortic PWV or backward wave pressures (Pb) (and hence central aortic pulse pressure [PPc]) and left ventricular mass index (LVMI) occur independent of each other. Aortic PWV, PPc, forward wave pressure (Pf), and Pb were determined using radial applanation tonometry and SphygmoCor software and LVMI using echocardiography; 44.5% of participants had an increased left ventricular mass indexed to height1.7. With adjustments for age, brachial systolic blood pressure or PP, and additional confounders, PPc and Pb, but not Pf, were independently related to LVMI and left ventricular hypertrophy (LVH) in both men and women. However, PWV was independently associated with LVMI in women (partial r = 0.16, P < .001), but not in men (partial r = 0.03), and PWV was independently associated with LVH in women (P < .05), but not in men (P = .07). With PWV and Pb included in the same multivariate regression models, PWV (partial r = 0.14, P < .005) and Pb (partial r = 0.10, P < .05) contributed to a similar extent to variations in LVMI in women. In addition, with PWV and Pb included in the same multivariate regression models, PWV (P < .05) and Pb (P < .02) contributed to LVH in women. In conclusion, aortic PWV and Pb (and hence pulse pressure) although both associated with LVMI and LVH produce effects which are independent of each other.