Assessing cardiovascular risk: should we discard diastolic blood pressure?

Hemodynamic profiles of arterial hypertension with ambulatory blood pressure monitoring

Blood pressure (BP) measurements obtained during a twenty-four-hour ambulatory blood pressure monitoring (24 h ABPM) have not been reliably applied to extract arterial hemodynamics. We aimed to describe the hemodynamic profiles of different hypertension (HT) subtypes derived from a new method for total arterial compliance (C_t) estimation in a large group of individuals undergoing 24 h ABPM. A cross-sectional study was conducted, which included patients with suspected HT. Cardiac output, C_t, and total peripheral resistance (TPR) were derived through a two-element Windkessel model without having a pressure waveform. Arterial hemodynamics were analyzed according to HT subtypes in 7434 individuals (5523 untreated HT and 1950 normotensive controls [N]). The individuals mean age was 46.2 ± 13.0 years; 54.8% were male, and 22.1% were obese. In isolated diastolic hypertension (IDH), the cardiac index (CI) was greater than that in normotensive (N) controls (CI: IDH vs. N mean difference 0.10 L/m/m²; CI 95% 0.08 to 0.12; p value <0.001), with no significant clinical difference in C_t. Isolated systolic hypertension (ISH) and divergent systolic-diastolic hypertension (D-SDH) had lower C_t values than nondivergent HT subtype (C_t: divergent vs. nondivergent mean difference -0.20 mL/mmHg; CI 95% -0.21 to -0.19 mL/mmHg; p value <0.001). Additionally, D-SDH displayed the highest TPR (TPR: D-SDH vs. N mean difference 169.8 dyn*s/cm^-5; CI 95% 149.3 to 190.3 dyn*s/cm^-5; p value <0.001). A new method is provided for the simultaneous assessment of arterial hemodynamics with 24 h ABPM as a single diagnostic tool, which allows a comprehensive assessment of arterial function for hypertension subtypes. Main hemodynamic findings in arterial HT subtypes with regard to C_t and TPR. The 24 h ABPM profile reflects the state of C_t and TPR. Younger individuals with IDH present with a normal C_t and frequently increased CO. Patients with ND-SDH maintain an adequate C_t with a higher TPR, while subjects with D-SDH present with a reduced C_t, high PP and high TPR. Finally, the ISH subtype occurs in older individuals with significantly reduced C_t, high PP and a variable TPR proportional to the degree of arterial stiffness and MAP values. There was an observed increase in PP with age in relation to the changes in C_t (see also text). SBP: systolic blood pressure; DBP: diastolic blood pressure; MAP: mean arterial pressure; PP: pulse pressure; N: normotension; HT: hypertension; IDH: isolated diastolic hypertension; ND-SDH: nondivergent systole-diastolic hypertension; D-SDH: divergent systolic-diastolic hypertension; ISH: isolated systolic hypertension; C_t: total arterial compliance; TPR: total peripheral resistance; CO: cardiac output; 24 h ABPM: 24 h ambulatory blood pressure monitoring.

Mid- to Late-Life Time-Averaged Cumulative Blood Pressure and Late-Life Retinal Microvasculature: The ARIC Study

Background The associations of time-averaged cumulative blood pressure (BP) from midlife to late life with microvasculature expressed as retinal vessel diameters is not well studied. The aim of this study was to evaluate the association of cumulative systolic BP and diastolic BP (DBP) with retinal vessel calibers, focusing on race differences. Methods and Results The analysis included 1818 adults from the ARIC (Atherosclerosis Risk in Communities) study attending the fifth visit (2011-2013; age 77±5 years, 17.1% Black participants). Time-averaged cumulative BPs were calculated as the sum of averaged BPs from adjacent consecutive visits (visits 1-5) indexed to total observation time (24±1 years). Summarized estimates for central retinal arteriolar equivalent and central retinal venular equivalent at the fifth visit represent average retinal vessel diameters. The arteriole:venule ratio was calculated. We tested for effect modification by race. Results from multiple linear regression models suggested that higher time-averaged cumulative DBP (β [95% CI] per 1-SD increase: -1.78 [-2.53, -1.02], P<0.001 and -0.005 [-0.009, -0.002], P=0.004, respectively) but not systolic BP (-0.52 [-1.30, 0.26], P=0.189 and 0.001 [-0.002, 0.005], P=0.485, respectively) was associated with smaller central retinal arteriolar equivalent and arteriole:venule ratio. The association between time-averaged cumulative DBP and arteriole:venule ratio was strongest in White participants (interaction P=0.007). The association of cumulative systolic BP and DBP with central retinal venular equivalent was strongest in Black participants (interaction P=0.015 and 0.011, respectively). Conclusions Exposure to higher BP levels, particularly DBP, from midlife to late life is associated with narrower retinal vessel diameters in late life. Furthermore, race moderated the association of cumulative BP exposure with retinal microvasculature.

Measures of Left Ventricular Diastolic Function and Cardiorespiratory Fitness According to Glucose Metabolism Status: The Maastricht Study

Background

This cross‐sectional study evaluated associations between structural and functional measures of left ventricular diastolic function and cardiorespiratory fitness (CRF) in a well‐characterized population‐based cohort stratified according to glucose metabolism status.

Methods and Results

Six hundred seventy‐two participants from The Maastricht Study (mean±SD age, 61±9 years; 17.4% prediabetes and 25.4% type 2 diabetes mellitus) underwent both echocardiography to determine left atrial volume index, left ventricular mass index, maximum tricuspid flow regurgitation, average e′ and E/e′ ratio; and submaximal cycle ergometer test to determine CRF as maximum power output per kilogram body mass. Associations were examined with linear regression adjusted for cardiovascular risk and lifestyle factors, and interaction terms. After adjustment, in normal glucose metabolism but not (pre)diabetes, higher left atrial volume index (per 1 mL/m²), left ventricular mass index (per 1 g/m^2.7), maximum tricuspid regurgitation flow (per 1 m/s) were associated with higher CRF (maximum power output per kilogram body mass; β in normal glucose metabolism 0.015 [0.008–0.023], P_interaction (pre)diabetes <0.10; 0.007 [−0.001 to 0.015], P_interaction type 2 diabetes mellitus <0.10; 0.129 [0.011–0.246], P_interaction >0.10; for left atrial volume index, left ventricular mass index, maximum tricuspid regurgitation flow, respectively). Furthermore, after adjustment, in all individuals, higher average E/e′ ratio (per unit), but not average e′, was associated with lower CRF (normal glucose metabolism −0.044 [−0.071 to −0.016]), P_interaction >0.10).

Conclusions

In this population‐based study, structural and functional measures of left ventricular diastolic function were independently differentially associated with CRF over the strata of glucose metabolism status. This suggests that deteriorating left ventricular diastolic function, although of small effect, may contribute to the pathophysiological process of impaired CRF in the general population. Moreover, the differential effects in these structural measures may be the consequence of cardiac structural adaptation to effectively increase CRF in normal glucose metabolism, which is absent in (pre)diabetes.

Prevalence and risks of hypertension among Indian tribes and its status among the lean and underweight individuals

OBJECTIVE

With the increased worldwide prevalence of hypertension among the underprivileged populations, fewerstudies have reported such risks among Indian tribes. In the context of high prevalence of undernutrition, no such study has examined hypertension among lean and underweight Indian tribal individuals separately.

METHODS

We selected total samples of 1066 adult males and 1090 adult females in 20-60 years age-group cross-sectionally to examine the status of hypertension and its risks among nine major tribes in three Indian states; separate analyses for lean and underweight tribal individuals were done.

RESULTS

Increased prevalence of hypertension (females, 14.2%; males, 9.3%) was observed among the tribes with the overall percentage of individuals at adversity (hypertensive + isolated hypertensive) at more than 20% (males 20.1%; females 26.5%). Age-group-wise prevalence showed a sharp rise in the prevalence of hypertension in the 40 + year individuals; additionally, this rise was alarming among females. Undernutrition was observed to be a potential risk factor as a remarkable prevalence of hypertension was observed among the undernourished (approximately 9%) and lean tribal participants (12%). Underweight females were observed to be at higher risk. Tribal statuses were observed to be alarming than the national trends due to their very low average BMI along with high average SBP. A curvilinear prevalence of hypertension was observed while comparing through both the nutritional extremes.

CONCLUSION

The increased prevalence and risks of hypertension in the background of lean and underweight status of Indian tribes indicates their epidemiological transition burdened with alarming cardio-metabolic health risks that warrant an early and consistent surveillance.

Evaluation of tolerance to ambulatory blood pressure monitoring: Analysis of dipping profile in a large cohort of hypertensive patients

Ambulatory blood pressure monitoring (ABPM) is a helpful tool to comprehensively identify and diagnose arterial hypertension. Moreover, it allows to better identify alterations in the circadian BP profile, as the nocturnal "nondipping" status, characterized by a lack of the physiological 10% night BP reduction and associated with a greater risk of target organ damage. However, ABPM has some limitations such as restricted availability, discomfort, particularly at night, cost implications, and reproducibility.Aim of the study was evaluate if the "nondipping" phenomenon may be related to low degree of tolerance to ABPM. Additionally, to determine whether self-reported events of sleep disorders and nighttime urinations may affect the "nondipping" status.From January 2013 to December 2015, we consecutively evaluated 1046 patients with arterial hypertension, performing ABPM, considering a tolerance index calculated on the basis of the patients' responses to a questionnaire.Thirty-eight out of 1046 patients showed complete lack of tolerance to the instrument during the day, whilst 126 during the night. There were no statistically significant differences in daytime and nighttime values of tolerance to the instrument between "dippers" and "nondippers," between "extreme-dippers" and the remaining patients or between "reverse-dippers" and the remaining patients. There were no statistically significant differences in the number of nocturnal awakenings between the groups. However, we found that the number of awakenings followed by urination was higher in "nondipping" patients and in "reverse-dipping" patients compared to the other groups.We found that the poor tolerance to the instrument does not seem to influence the BP "dipping" phenomenon among hypertensive individuals. Moreover, we think that in the evaluation of the ABPM data, factors, such as nocturnal urination and sleep disorders, need to be carefully taken into account, since may lead to a higher incidence of "nondipping" pattern.

Predicting blood pressure outcomes using single-item physician-administered measures: a retrospective pooled analysis of observational studies in Belgium

BACKGROUND

Patient adherence is often not monitored because existing methods of evaluating adherence are either burdensome or do not accurately predict treatment outcomes.

AIM

To examine whether two simple, single-item physician-administered measures of patient adherence to antihypertensive medication are predictive of blood pressure outcomes.

DESIGN AND SETTING

Retrospective database analysis of patients with hypertension treated in Belgian primary care.

METHOD

Using pooled data from five observational studies, a sample was identified of 9725 patients who were assessed using two single-item physician-administered measures of adherence to antihypertensive medication: the first item of the Basel Assessment of Adherence Scale (BAAS) and the Visual Analogue Scale (VAS). These two assessment tools were administered by GPs during regular appointments with patients. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and combined SBP/DBP were measured at baseline and at 90 days.

RESULTS

BAAS-identified adherent patients achieved lower mean SBP and DBP compared with non-adherent patients at 90 days (P<0.001), and had odds ratios of achieving blood pressure control of 0.66 (95% confidence intervals (CI) = 0.61 to 0.73, P<0.001) for SBP, 0.69 (95% CI = 0.62 to 0.76, P<0.001) for DBP, and 0.65 (95% CI = 0.59 to 0.72, P<0.001) for combined SBP/DBP. For VAS-identified adherent patients, the odds ratios of achieving blood pressure control were 0.93 (95% CI = 0.86 to 1.00, P<0.001) for SBP, 0.79 (95% CI = 0.73 to 0.85, P<0.001) for DBP, and 0.91 (95% CI = 0.84 to 0.99, P<0.001) for combined SBP/DBP.

CONCLUSIONS

The first item of the BAAS and the VAS are independent predictors of blood pressure control. These methods can be integrated seamlessly into routine clinical practice by allowing GPs to quickly evaluate a patient's adherence and tailor treatment recommendations accordingly.

Relationship Between Blood Pressure Values, Depressive Symptoms, and Cardiovascular Outcomes in Patients With Cardiometabolic Disease

The authors studied the joint effect of blood pressure (BP) and depression on the risk of major adverse cardiovascular outcome in patients with existing cardiometabolic disease. A cohort of 35,537 patients with coronary heart disease, diabetes, or stroke underwent depression screening and BP measurement recorded concurrently. The authors used Cox's proportional hazards to calculate risk of major adverse cardiovascular event (MACE; myocardial infarction/heart failure/stroke or cardiovascular death) over 4 years associated with baseline BP and depression. A total of 11% (3939) had experienced a MACE within 4 years. Patients with very high systolic BP (160-240 mm Hg; hazard ratio, 1.28) and depression (hazard ratio, 1.22) at baseline had significantly higher adjusted risk. Depression had a significant interaction with systolic BP in risk prediction (P=.03). Patients with a combination of high systolic BP and depression at baseline had 83% higher adjusted risk of MACE, as compared with patients with reference systolic BP without depression. Patients with cardiometabolic disease and comorbid depression may benefit from closer monitoring of systolic BP.

Using the Generalized Index of Dissimilarity to Detect Gene-Gene Interactions in Multi-Class Phenotypes

To find genetic association between complex diseases and phenotypic traits, one important procedure is conducting a joint analysis. Multifactor dimensionality reduction (MDR) is an efficient method of examining the interactions between genes in genetic association studies. It commonly assumes a dichotomous classification of the binary phenotypes. Its usual approach to determining the genomic association is to construct a confusion matrix to estimate a classification error, where a binary risk status is determined and assigned to each genotypic multifactor class. While multi-class phenotypes are commonly observed, the current MDR approach does not handle these phenotypes appropriately because the thresholds for the risk statuses may not be clear. In this study, we suggest a new method for estimating gene-gene interactions for multi-class phenotypes. Our approach adopts the index of dissimilarity (IDS) as an evaluation measure. This is analytically equivalent to the common association measure of balanced accuracy (BA) for the binary traits, while it is not required to determine the risk status for the estimation. Moreover, it is easily expandable to the generalized index of dissimilarity (GIDS), which has an explicit form that can handle any number of categories. The performance of the proposed method was compared with those of other approaches via simulation studies in which fifteen genetic models were generated with three class outcomes. A consistently better performance was observed using the proposed method. The effect of a varying number of categories was examined. The proposed method was also illustrated using real genome-wide association studies (GWAS) data from the Korean Association Resource (KARE) project.

Differential influence of distinct components of increased blood pressure on cardiovascular outcomes: from the atherosclerosis risk in communities study

Elevation in blood pressure (BP) increases risk for all cardiovascular events. Nevertheless, the extent to which different indices of BP elevation may be associated to varying degrees with different cardiovascular outcomes remains unclear. We studied 13340 participants (aged 54 ± 6 years, 56% women and 27% black) of the Atherosclerosis Risk in Communities Study who were free of baseline cardiovascular disease. We used Cox proportional hazards models to compare the relative contributions of systolic BP, diastolic BP, pulse pressure, and mean arterial pressure to risk for coronary heart disease, heart failure, stroke, and all-cause mortality. For each multivariable-adjusted model, the largest area under the receiver-operating curve (AUC) and smallest -2 log-likelihood values were used to identify BP measures with the greatest contribution to risk prediction for each outcome. A total of 2095 coronary heart disease events, 1669 heart failure events, 771 stroke events, and 3016 deaths occurred during 18 ± 5 years of follow-up. In multivariable analyses adjusting for traditional cardiovascular risk factors, the BP measures with the greatest risk contributions were the following: systolic BP for coronary heart disease (AUC=0.74); pulse pressure for heart failure (AUC=0.79); systolic BP for stroke (AUC=0.74); and pulse pressure for all-cause mortality (AUC=0.74). With few exceptions, results were similar in analyses stratified by age, sex, and race. Our data indicate that distinct BP components contribute variably to risk for different cardiovascular outcomes.

Secular trends in blood pressure during early-to-middle adulthood: the Fels Longitudinal Study

BACKGROUND

Some studies have shown a decline in blood pressure (BP) over the second half of the twentieth century. However, the increasing prevalence of obesity may have opposite effects on recent cohorts.

METHOD

Using serial BP data from the Fels Longitudinal Study, we examined secular trends in mean BP, the rate of change in BP with age (slopes), and the influence of obesity (i.e., BMI) and height on these trends during young-to-middle adulthood. The study sample consisted of 970 adults, aged 18-40 years, who were born between 1920 and 1979. Participants were grouped into birth decade cohorts and had up to 11 serial measurements of SBP, DBP, and BMI. Sex-stratified mixed longitudinal analyses were used to identify cohort effects on mean BP at ages 19, 29, and 39 years, and on the rate of change in BP with age.

RESULTS

For both sexes, mean SBP did not vary significantly by birth cohort, before and after adjusting for height and BMI. Mean DBP exhibited a U-shaped secular trend even after adjusting for BMI and height that was influenced by age-by-cohort effects. By age 39 years, those born most recently had the highest mean DBP.

CONCLUSION

There were cohort effects on the rate of change in DBP with age, but not on rate of SBP change. The most recent cohorts had higher rates of DBP change with age compared to the earlier cohorts. The secular trend was partially influenced by the trends in BMI.

The dominant role of the systolic component of nondipping status on target-organ damage in never-treated hypertensives

BACKGROUND

Blood pressure (BP) nondipping has been associated with target-organ damage (TOD) and adverse outcomes in hypertension. Diverse definitions of nondipping status appear in the literature, regarding the BP components taken into account. Aim of this study was to compare the effects of isolated nondipping of systolic, diastolic and combined systolic and diastolic BP on various indices of TOD.

METHODS

From 630 consecutive subjects with never-treated essential hypertension stage I-II, we selected 279 subjects who were consistently isolated systolic nondippers (SND, n=76) isolated diastolic nondippers (DND, n=64) and combined systolic and diastolic nondippers (SDND, n=139) in two ambulatory BP monitoring sessions. All three subgroups were subjected to echocardiographic examination, carotid-femoral pulse wave velocity (PWV(c-f)) and albumin-to-creatinine ratio (ACR) determination. Metabolic profile was determined in a morning blood sample.

RESULTS

SND compared to DND and SDND exhibited higher left ventricular mass/height(2.7) (42.4 ± 9.9 vs. 38.0 ± 9.1 vs. 40.9 ± 11.0 g/m(2.7), P < 0.05), higher log(10)(PWV(c-f)) (0.94 ± 0.07 vs. 0.86 ± 0.05 vs. 0.91 ± 0.07 m/s, P < 0.005), and higher log(10)(ACR) (1.2 ± 0.5 vs. 0.9 ± 0.3 vs. 1.1 ± 0.4 mg/g, P < 0.05). Isolated systolic BP nondipping was an independent determinant of all the studied indices of TOD whereas isolated diastolic BP nondipping was not.

CONCLUSIONS

Isolated systolic as compared to diastolic and to combined systolic/diastolic BP nondipping is associated with higher left ventricular mass, stiffer arteries, and pronounced urinary albumin excretion.

Altered health outcomes in adult offspring of Sprague Dawley and Wistar rats undernourished during early or late pregnancy

BACKGROUND

Birth weight in humans has been inversely associated with adult disease risk. Results of animal studies have varied depending on species, strain, and treatment.

METHODS

We compared birth weight and adult health in offspring following 50% maternal undernutrition on gestation days (GD) 1-15 (UN1-15) or GD 10-21 (UN10-21) in Sprague Dawley and Wistar rats. Offspring from food-deprived dams were weighed and cross-fostered to control dams. Litters were weighed during lactation and initiating at weaning males were fed either control or a high-fat diet. Young and mature adult offspring were evaluated for obesity, blood pressure (BP), insulin response to oral glucose, and serum lipids. Nephron endowment, renal glucocorticoid receptor, and renin-aldosterone-angiotensin system components were measured.

RESULTS

The UN10-21 groups had birth weights lower than controls and transient catch up growth by weaning. Neither strain demonstrated obesity or dyslipidemia following prenatal undernutrition, but long-term body weight deficits occurred in the UN groups of both strains. High-fat diet fed offspring gained more weight than control offspring without an effect of prenatal nutrition. Sprague Dawley were slightly more susceptible than Wistar rats to altered insulin response and increased BP following gestational undernutrition. Nephron endowment in Sprague Dawley but not Wistar offspring was lower in the UN10-21 groups. Glucocorticoid and renin-aldosterone-angiotensin system pathways were not altered.

CONCLUSIONS

The most consistent effect of maternal undernutrition was elevated BP in offspring. Long-term health effects occurred with undernutrition during either window, but the UN10-21 period resulted in lower birth weight and more severe adult health effects.

Reliability of palpation of the radial artery compared with auscultation of the brachial artery in measuring SBP

BACKGROUND

Systolic blood pressure contributes more to cardiovascular disease than DBP, especially in elderly persons. Palpation of the radial artery to assess SBP - Riva-Rocci's technique - may be an attractive alternative for auscultatory SBP in these patients. Therefore, we investigated the difference between SBP determined by palpation of the radial artery (pSBP) and SBP assessed by auscultation of the brachial artery (aSBP).

METHODS

Patients were included from the waiting room of a hypertension outpatient clinic. In each patient eight simultaneous pSBP and aSBP measurements were assessed by two observers in the same arm. After every two readings the observers switched between pSBP and aSBP.

RESULTS

Forty patients were included, 25 men (62.5%), mean age 55.3 years (range 24-78). From a total of 320 measurements, mean difference between pSBP and aSBP was -5.2 mmHg (range -12-26 mmHg) (P < 0.01). This difference correlated significantly with BMI (r = 0.51, P < 0.01), but not with age (r = 0.15, P = 0.35), pulse rate (r = 0.29, P = 0.09) or mean SBP (r = 0.03, P = 0.85). After averaging the first three comparisons, reproducibility did not improve when increasing the number of comparisons. When correcting for the underestimation of 6 mmHg over the first three comparisons, Riva-Rocci's technique estimates SBP with an acceptable accuracy.

CONCLUSION

In clinical practice, Riva-Rocci's palpatory technique offers an acceptable alternative for auscultatory SBP measurement. It is recommended to take three measurements and then correct for the average underestimation of 6 mmHg.