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Clustering of arterial blood pressure (BP) waveform parameters could summarize complex information into distinct elements, which could be used to investigate cumulative (nonredundant) associations. We investigated this hypothesis in a large, adult population-based study (ViDA trial [Vitamin D Assessment] trial). To interpret the clusters and evaluate their usefulness, we examined their predictors and associations with cardiovascular events. In 4253 adults (mean age 65 years; 55% male) without a prior cardiovascular event, suprasystolic oscillometry was performed, yielding aortic pressure waveforms and several hemodynamic parameters. Participants were followed up for 4.6 years (median), accruing 300 cardiovascular events. Principal component analysis reduced 14 arterial waveform parameters to 3 uncorrelated factors that together explained 90% of the variability of the original data. Factors 1, 2, and 3 appeared to represent BP pulsatility, mean BP, and wave reflection, respectively. Across 6 antihypertensive drug classes, there were no differences in brachial systolic ( P =0.23) and diastolic ( P =0.13) BP; but there were significant variations in factor 3 ( P <0.0001), especially for β-blocker use. The first and third factors were positively associated with cardiovascular events (multivariable-adjusted standardized hazard ratio [95% CI]=1.33 [1.18-1.50] and 1.15 [1.02-1.30], respectively), whereas the second factor had a J-shaped relationship, with a nadir corresponding to a brachial diastolic BP of ≈75 mm Hg. In conclusion, BP pulsatility, mean BP, and wave reflection are prognostically meaningful, distinct aspects of arterial function that can be used to summarize physiological variations in multiple arterial waveform parameters and identify truly cumulative associations when used as cardiovascular risk outcomes.

Discontinuation of angiotensin-converting enzyme (ACE) inhibitor is recommended if patients experience ≥30% acute increase in serum creatinine after starting this therapy. However, the long-term effects of its continuation or discontinuation on major clinical outcomes after increases in serum creatinine are unclear. In the ADVANCE trial (Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation), 11 140 diabetes mellitus patients were randomly assigned to perindopril-indapamide or placebo after a 6-week active run-in period. The current study included 11 066 participants with 2 serum creatinine measurements recorded before and during the active run-in period (3 weeks apart). Acute increase in creatinine was determined using these 2 measurements and classified into 4 groups: increases in serum creatinine of <10%, 10% to 19%, 20% to 29%, and ≥30%. The primary study outcome was the composite of major macrovascular events, new or worsening nephropathy, and all-cause mortality. An acute increase in serum creatinine was associated with an elevated risk of the primary outcome ( P for trend <0.001). The hazard ratios were 1.11 (95% CI, 0.97-1.28) for those with an increase of 10% to 19%, 1.34 (1.07-1.66) for 20% to 29%, and 1.44 (1.15-1.81) for ≥30%, compared with <10%. However, there was no evidence of heterogeneity in the benefit of randomized treatment effects on the outcome across subgroups defined by acute serum creatinine increase ( P for heterogeneity=0.94). Acute increases in serum creatinine after starting perindopril-indapamide were associated with greater risks of subsequent major clinical outcomes. However, the continuation of angiotensin-converting enzyme inhibitor-based therapy reduced the long-term risk of major clinical outcomes, irrespective of acute increase in creatinine. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT00145925.

Elevated blood pressure is a major risk factor for cardiovascular disease and has a substantial genetic contribution. Genetic variation influencing blood pressure has the potential to identify new pharmacological targets for the treatment of hypertension. To discover additional novel blood pressure loci, we used 1000 Genomes Project-based imputation in 150 134 European ancestry individuals and sought significant evidence for independent replication in a further 228 245 individuals. We report 6 new signals of association in or near HSPB7 , TNXB , LRP12 , LOC283335 , SEPT9 , and AKT2 , and provide new replication evidence for a further 2 signals in EBF2 and NFKBIA . Combining large whole-blood gene expression resources totaling 12 607 individuals, we investigated all novel and previously reported signals and identified 48 genes with evidence for involvement in blood pressure regulation that are significant in multiple resources. Three novel kidney-specific signals were also detected. These robustly implicated genes may provide new leads for therapeutic innovation.

Visit-to-visit variability in systolic blood pressure (SBP) is a risk factor for cardiovascular events. However, whether it provides additional predictive information beyond traditional risk factors, including mean SBP, in the long term is unclear. The ADVANCE trial (Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation) was a randomized controlled trial in patients with type 2 diabetes mellitus; ADVANCE-ON (ADVANCE-Observational) followed-up patients subsequently. In these analyses, 9114 patients without major macrovascular or renal events or death during the first 24 months were included. Data on SBP from 6 visits during the first 24 months after randomization were used to estimate visit-to-visit variability in several ways: the primary measure was the standard deviation. Events accrued during the following 7.6 years. The primary outcome was a composite of major macrovascular and renal events and all-cause mortality. Standard deviation of SBP was log-linearly associated with an increased risk of the primary outcome ( P <0.001) after adjustment for mean SBP and other cardiovascular risk factors. The hazard ratio (HR; 95% confidence interval [CI]) in the highest, compared with the lowest, tenth of the standard deviation was 1.39 (1.15-1.69). Results were similar for major macrovascular events alone and all-cause mortality alone (both P <0.01). Addition of standard deviation of SBP significantly improved 8-year risk classification (continuous net reclassification improvement, 5.3%). Results were similar for other measures of visit-to-visit variability, except maximum SBP. Visit-to-visit variability in SBP is an independent predictor of vascular complications and death, which improves risk prediction beyond that provided by traditional risk factors, including mean SBP., (© 2017 American Heart Association, Inc.)

Several morphological parameters based on the central aortic pressure waveform are proposed as cardiovascular risk markers, yet no study has definitively demonstrated the incremental value of any waveform parameter in addition to currently accepted biomarkers in elderly, hypertensive patients. The reservoir-wave concept combines elements of wave transmission and Windkessel models of arterial pressure generation, defining an excess pressure superimposed on a background reservoir pressure. The utility of pressure rate constants derived from reservoir-wave analysis in prediction of cardiovascular events is unknown. Carotid blood pressure waveforms were measured prerandomization in a subset of 838 patients in the Second Australian National Blood Pressure Study. Reservoir-wave analysis was performed and indices of arterial function, including the systolic and diastolic rate constants, were derived. Survival analysis was performed to determine the association between reservoir-wave parameters and cardiovascular events. The incremental utility of reservoir-wave parameters in addition to the Framingham Risk Score was assessed. Baseline values of the systolic rate constant were independently predictive of clinical outcome (hazard ratio, 0.33; 95% confidence interval, 0.13-0.82; P=0.016 for fatal and nonfatal stroke and myocardial infarction and hazard ratio, 0.38; 95% confidence interval, 0.20-0.74; P=0.004 for the composite end point, including all cardiovascular events). Addition of this parameter to the Framingham Risk Score was associated with an improvement in predictive accuracy for cardiovascular events as assessed by the integrated discrimination improvement and net reclassification improvement indices. This analysis demonstrates that baseline values of the systolic rate constant predict clinical outcomes in elderly patients with hypertension and incrementally improve prognostication of cardiovascular events., (© 2014 American Heart Association, Inc.)

Excess pressure integral (XSPI), a new index of surplus work performed by the left ventricle, can be calculated from blood pressure waveforms and may indicate circulatory dysfunction. We investigated whether XSPI predicted future cardiovascular events and target organ damage in treated hypertensive individuals. Radial blood pressure waveforms were acquired by tonometry in 2069 individuals (aged, 63±8 years) in the Conduit Artery Functional Evaluation (CAFE) substudy of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT). Measurements of left ventricular mass index (n=862) and common carotid artery intima media thickness (n=923) were also performed. XSPI and the integral of reservoir pressure were lower in people treated with amlodipine±perindopril than in those treated with atenolol±bendroflumethiazide, although brachial systolic blood pressure was similar. A total of 134 cardiovascular events accrued during a median 3.4 years of follow-up; XSPI was a significant predictor of cardiovascular events after adjustment for age and sex, and this relationship was unaffected by adjustment for conventional cardiovascular risk factors or Framingham risk score. XSPI, central systolic blood pressure, central augmentation pressure, central pulse pressure, and integral of reservoir pressure were correlated with left ventricular mass index, but only XSPI, augmentation pressure, and central pulse pressure were associated positively with carotid artery intima media thickness. Associations between left ventricular mass index, XSPI, and integral of reservoir pressure and carotid artery intima media thickness and XSPI were unaffected by multivariable adjustment for other covariates. XSPI is a novel indicator of cardiovascular dysfunction and independently predicts cardiovascular events and targets organ damage in a prospective clinical trial., (© 2014 American Heart Association, Inc.)

Cardiometabolic risk is elevated in South Asians and African Caribbeans compared with Europeans, yet whether this is associated with ethnic differences in left-ventricular structure is unclear. Conventional M-mode or 2-dimensional echocardiography may be misleading, because they calculate left-ventricular mass and remodeling using geometric assumptions. Left-ventricular structure was compared in a triethnic population-based cohort using conventional and 3-dimensional echocardiography on 895 individuals (aged 55-85 years; 427 European, 325 South Asian, 143 African Caribbean). Left-ventricular mass was indexed, and left-ventricle remodeling index and relative wall thickness were calculated. Anthropometry, blood pressure, and fasting bloods were measured. Three-dimensional left-ventricular mass index did not differ between Europeans (mean ± SE, 29.8 ± 0.3 g/m(2.7)) and African Caribbeans (29.9 ± 0.5 g/m(2.7); P=0.9), but it was significantly lower in South Asians (28.1 ± 0.4 g/m(2.7); P<0.0001) compared with Europeans. These findings persisted on multivariate adjustment. In contrast, conventional left-ventricle mass index was significantly higher in African Caribbeans (46.4 ± 0.9 g/m(2.7)) than in Europeans (41.9 ± 0.5 g/m(2.7); P<0.0001). Left-ventricle remodeling index was the highest in African Caribbeans and the lowest in South Asians. Relative wall thickness was also higher in African Caribbeans, but no different in South Asians, compared with Europeans. Differences in left-ventricle remodeling index were attenuated by adjustment for cardiometabolic factors between African Caribbeans and Europeans only. In conclusion, left-ventricular mass is lower in South Asians and equivalent in African Caribbeans compared with Europeans, even when cardiometabolic risk factors are accounted for. Left-ventricular remodeling rather than hypertrophy may explain the increased risk of heart failure in people of African Caribbean origin.

Wave reflection is thought to be important in the augmentation of blood pressure. However, identification of distal reflections sites remains unclear. One possible explanation for this is that wave reflection is predominately determined by an amalgamation of multiple proximal small reflections rather than large discrete reflections originating from the distal peripheries. In 19 subjects (age, 35-73 years), sensor-tipped intra-arterial wires were used to measure pressure and Doppler velocity at 10-cm intervals along the aorta, starting at the aortic root. Incident and reflected waves were identified and timings and magnitudes quantified using wave intensity analysis. Mean wave speed increased along the length of the aorta (proximal, 6.8±0.9 m/s; distal, 10.7±1.5 m/s). The incident wave was tracked moving along the aorta, taking 55±4 ms to travel from the aortic root to the distal aorta. However, the timing to the refection site distance did not differ between proximal and distal aortic measurement sites (proximal aorta, 48±5 ms versus distal aorta, 42±4 ms; P=0.3). We performed a second analysis using aortic waveforms in a nonlinear model of pulse-wave propagation. This demonstrated very similar results to those observed in vivo and also an exponential attenuation in reflection magnitude. There is no single dominant refection site in or near the distal aorta. Rather, there are multiple reflection sites along the aorta, for which the contributions are attenuated with distance. We hypothesize that rereflection of reflected waves leads to wave entrapment, preventing distal waves being seen in the proximal aorta.

Thiazide and thiazide-like diuretics are widely used in the management of hypertension, but recently the equivalence of hydrochlorothiazide and chlorthalidone for blood pressure (BP) lowering and prevention of cardiovascular disease has been questioned. We performed a meta-analysis to characterize the dose-response relationships for 3 commonly prescribed thiazide diuretics, hydrochlorothiazide, chlorthalidone, and bendroflumethiazide, on BP, serum potassium, and urate. Randomized, double-blind, parallel placebo-controlled trials meeting the following criteria, ≥ 2 different monotherapy dose arms, follow-up duration ≥ 4 weeks, and baseline washout of medication ≥ 2 weeks, were identified using Embase (1980-2010 week 50), Medline (1950-2010 November week 3), metaRegister of Controlled Trials, and Cochrane Central. A total of 26 trials examined hydrochlorothiazide, 3 examined chlorthalidone, and 1 examined bendroflumethiazide. Studies included a total of 4683 subjects in >53 comparison arms. Meta-regression of the effect of thiazides on systolic BP showed a log-linear relationship with a potency series: bendroflumethiazide>chlorthalidone>hydrochlorothiazide. The estimated dose of each drug predicted to reduce systolic BP by 10 mm Hg was 1.4, 8.6, and 26.4 mg, respectively, and there was no evidence of a difference in maximum reduction of systolic BP by high doses of different thiazides. Potency series for diastolic BP, serum potassium, and urate were similar to those seen for systolic BP. Hydrochlorothiazide, chlorthalidone, and bendroflumethiazide have markedly different potency. This may account for differences in the antihypertensive effect between hydrochlorothiazide and chlorthalidone using standard dose ranges.

Two or more antihypertensive agents are increasingly used to control blood pressure (BP) in hypertensive patients. However, it is unclear whether fixed-dose combinations (FDCs) of 2 antihypertensive agents in a single tablet provide greater benefits than the corresponding free-drug components given separately. A meta-analysis was performed to assess compliance, persistence, BP control, and safety associated with FDCs in comparison with their free-drug components. Fifteen included studies (n=32331) reported on >or=1 of the evaluated outcomes. In 3 cohort studies and 2 trials reporting on drug compliance (n=17 999), the use of FDCs was associated with significantly better compliance (odds ratio: 1.21 [95% CI: 1.03 to 1.43]; P=0.02) compared with its corresponding free-drug combinations. In 3 cohort studies (n=12 653), there was a nonsignificant improvement in persistence with therapy (odds ratio: 1.54 [95% CI: 0.95 to 2.49]; P=0.08), and in 5 trials (n=1775) the odds ratio for adverse effects for FDC use compared with free-drug combination use was 0.80 (95% CI: 0.58 to 1.11; P=0.19). In 9 trials (n=1671) with BP data, use of an FDC was associated with nonsignificant changes in systolic and diastolic BPs of 4.1 mm Hg (95% CI: -9.8 to 1.5; P=0.15) and 3.1 mm Hg (95% CI: -7.1 to 0.9; P=0.13), respectively. In these BP-lowering comparisons, there was heterogeneity associated with differences in study design but no publication bias. In conclusion, compared with free-drug combinations, FDCs of antihypertensive agents are associated with a significant improvement in compliance and with nonsignificant beneficial trends in BP and adverse effects.

Hydroxymethylglutaryl-CoA reductase inhibitors (statins) reduce cardiovascular events in hypertensive subjects, but their effect on carotid BP, pressure augmentation, and wave reflection is unknown. We compared the effect of atorvastatin with placebo in a substudy of the lipid-lowering arm of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT-LLA). Hypertensive patients (n=142; age=43 to 79 years; 127 male) with total cholesterol < or = 6.5 mmol/L were randomized to atorvastatin 10 mg or placebo. Carotid BP and flow velocity were measured by tonometry and Doppler ultrasound. Augmentation index (carotid AI(x)) was calculated, and waveforms were separated into backward and forward components by wave intensity analysis. Brachial BP was similar in atorvastatin and placebo groups. Carotid AI(x) and augmentation pressure were significantly less in patients randomized to atorvastatin (mean [SD]: 21.7 [12.1] versus 25.9 [10.3] %; P=0.027 and 10.2 [6.5] versus 13.1 [6.6] mm Hg; P=0.016, respectively), and atorvastatin treatment was associated with significantly less wave reflection from the body. Carotid systolic BP was slightly lower in the atorvastatin group, but there was a statistically significant interaction between lipid-lowering and antihypertensive regimen with lower carotid systolic BP in patients randomized to amlodipine-based therapy and atorvastatin. Carotid wave velocity, timings of waves, and wave intensities did not differ significantly between atorvastatin and placebo groups. Atorvastatin treatment is associated with less augmentation of the carotid BP waveform and less wave reflection from the body. This could contribute to the reduction in risk of cardiovascular events by statins.

Antihypertensive agents may differ in their effects on central systolic blood pressure, and this may contribute to treatment-related differences in cardiovascular outcomes. In a substudy of the Anglo-Scandinavian Cardiac Outcome Trial, we investigated whether directly measured carotid systolic blood pressure differed between people randomized to amlodipine- and atenolol-based therapies and whether this is accounted for by differences in wave reflection patterns. Additional analysis was undertaken to establish whether differences in carotid systolic blood pressure predicted left ventricular mass, accounting for between-treatment differences in left ventricular mass index. Blood pressure and flow velocity were measured in the right carotid artery of 259 patients. Wave intensity analysis was used to separate and quantify forward and backward waves. Brachial blood pressure did not differ significantly between groups, but carotid systolic blood pressure (127 [12] versus 133 [15] mm Hg; P<0.001), the ratio of backward:forward pressure (0.48 [0.17] versus 0.53 [0.19]; P=0.01), and wave reflection index (19.8% [10.9%] versus 23.3% [13.3%]; P=0.02) were significantly lower in patients randomized to amlodipine-based therapy. Left ventricular mass index was also lower in this group, and adjustment for carotid blood pressure attenuated treatment differences to a greater extent than brachial blood pressure. Carotid systolic blood pressure was also a significant independent predictor of left ventricular mass index in a multivariate model. Carotid systolic blood pressure is lower in people randomized to amlodipine-based compared with atenolol-based treatment despite there being no significant difference in brachial blood pressure. This difference is attributable to a lesser magnitude of wave reflection in patients randomized to the amlodipine-based regimen.

Changes in the retinal microcirculation are associated with hypertension and predict cardiovascular mortality. There are few data describing the impact of antihypertensive therapy on retinal vascular changes. This substudy of the Anglo-Scandinavian Cardiac Outcomes Trial compared the effects of an amlodipine-based regimen (373 patients) with an atenolol-based regimen (347 patients) on retinal microvascular measurements made from fundus photographs. The retinal photographs were taken at a stage in the trial when treatments were stable and blood pressure was well controlled. Amlodipine-based treatment was associated with a smaller arteriolar length:diameter ratio than atenolol-based treatment (13.32 [10.75 to 16.04] versus 14.12 [11.27 to 17.81], median [interquartile range]; P<0.01). The association remained significant after adjustment for age, sex, cholesterol, systolic and diastolic blood pressures, body mass index, smoking, and statin treatment. This effect appeared to be largely attributable to shorter retinal arteriolar segment lengths in the amlodipine-treated group and is best explained by the vasodilator effects of amlodipine causing the visible emergence of branching side vessels. Photographic assessment of the retinal vascular network may be a useful approach to evaluating microvascular structural responses in clinical trials of antihypertensive therapy.

Spironolactone is recommended as fourth-line therapy for essential hypertension despite few supporting data for this indication. We evaluated the effect among 1411 participants in the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm who received spironolactone mainly as a fourth-line antihypertensive agent for uncontrolled blood pressure and who had valid BP measurements before and during spironolactone treatment. Among those who received spironolactone, the mean age was 63 years (SD: +/-8 years), 77% were men, and 40% had diabetes. Spironolactone was initiated a median of 3.2 years (interquartile range: 2.0 to 4.4 years) after randomization and added to a mean of 2.9 (SD: +/-0.9) other antihypertensive drugs. The median duration of spironolactone treatment was 1.3 years (interquartile range: 0.6 to 2.6 years). The median dose of spironolactone was 25 mg (interquartile range: 25 to 50 mg) at both the start and end of the observation period. During spironolactone therapy, mean blood pressure fell from 156.9/85.3 mm Hg (SD: +/-18.0/11.5 mm Hg) by 21.9/9.5 mm Hg (95% CI: 20.8 to 23.0/9.0 to 10.1 mm Hg; P<0.001); the BP reduction was largely unaffected by age, sex, smoking, and diabetic status. Spironolactone was generally well tolerated; 6% of participants discontinued the drug because of adverse effects. The most frequent adverse events were gynecomastia or breast discomfort and biochemical abnormalities (principally hyperkaliemia), which were recorded as adverse events in 6% and 2% of participants, respectively. In conclusion, spironolactone effectively lowers blood pressure in patients with hypertension uncontrolled by a mean of approximately 3 other drugs. Although nonrandomized and not placebo controlled, these data support the use of spironolactone in uncontrolled hypertension.

Abnormalities of the retinal microcirculation are found in hypertension and diabetes and predict cardiovascular mortality. This study examined the relationship between abnormalities of the retinal microvasculature and death from ischemic heart disease (IHD) and stroke. A population-based, nested case-control study was undertaken within the Beaver Dam Eye Study. Subjects (43 to 74 years) who died of IHD (n=126) or stroke (n=28) over a 10-year period were age and gender matched with controls subjects (n=528; case:control matching, approximately 1:4). Retinal photographs of cases and controls were digitized and analyzed using a computer-based technique. Increased risk of IHD death was associated with a suboptimal relationship of arteriolar diameters at bifurcation (P=0.02 unadjusted) and decreased retinal arteriolar tortuosity (P=0.011 unadjusted). These associations remained significant after adjustment for age, sex, past history of cardiovascular disease, and other known cardiovascular risk factors. Increased arteriolar length:diameter ratio, a measure of generalized arteriolar narrowing, was associated with increased stroke mortality (P=0.02 unadjusted). This association was independent of age and gender but was attenuated by adjustment for systolic blood pressure (P=0.15). Other quantitative measures of the retinal microvascular network (eg, venular tortuosity and arteriolar and venular bifurcation angle) were not associated with death from IHD or stroke. Retinal microvascular abnormalities are predictive of death from IHD and stroke. A detailed assessment of the retinal microvascular network from digitized photographs may be useful in the noninvasive assessment of target organ damage and cardiovascular risk.