Left ventricular hypertrophy in hypertension. Prevalence and relationship to pathophysiologic variables

Hypertensive Heart Disease: A Narrative Review Series-Part 2: Macrostructural and Functional Abnormalities

Hypertensive heart disease (HHD) remains a major global public health concern despite the implementation of new approaches for the management of hypertensive patients. The pathological changes occurring during HHD are complex and involve the development of structural and functional cardiac abnormalities. HHD describes a broad spectrum ranging from uncontrolled hypertension and asymptomatic left ventricular hypertrophy (LVH), either a concentric or an eccentric pattern, to the final development of clinical heart failure. Pressure-overload-induced LVH is recognised as the most important predictor of heart failure and sudden death and is associated with an increased risk of cardiac arrhythmias. Cardiac arrhythmias are considered to be one of the most important comorbidities affecting hypertensive patients. This is the second part of a three-part set of review articles. Here, we focus on the macrostructural and functional abnormalities associated with chronic high pressure, their involvement in HHD pathophysiology, and their role in the progression and prognosis of HHD.

Multimodality Imaging in Sarcomeric Hypertrophic Cardiomyopathy: Get It Right…on Time

Hypertrophic cardiomyopathy (HCM) follows highly variable paradigms and disease-specific patterns of progression towards heart failure, arrhythmias and sudden cardiac death. Therefore, a generalized standard approach, shared with other cardiomyopathies, can be misleading in this setting. A multimodality imaging approach facilitates differential diagnosis of phenocopies and improves clinical and therapeutic management of the disease. However, only a profound knowledge of the progression patterns, including clinical features and imaging data, enables an appropriate use of all these resources in clinical practice. Combinations of various imaging tools and novel techniques of artificial intelligence have a potentially relevant role in diagnosis, clinical management and definition of prognosis. Nonetheless, several barriers persist such as unclear appropriate timing of imaging or universal standardization of measures and normal reference limits. This review provides an overview of the current knowledge on multimodality imaging and potentialities of novel tools, including artificial intelligence, in the management of patients with sarcomeric HCM, highlighting the importance of specific "red alerts" to understand the phenotype-genotype linkage.

Left ventricular structure and function in patients with chronic kidney disease assessed by 3D echocardiography: the CPH-CKD ECHO study

Cardiovascular disease is the leading cause of mortality amongst patients with chronic kidney disease (CKD). This is the first study using 3-dimensional echocardiography (3DE) to investigate associations between adverse changes of the left ventricle, and different stages of CKD. Participants were recruited from the Copenhagen CKD cohort study and the Herlev-Gentofte CKD cohort study. Patients were stratified according to GFR category (G1 + 2: eGFR ≥ 60 mL/min/1.73 m2, G3: eGFR = 30-59 mL/min/1.73 m2, and G4 + 5: eGFR ≤ 29 mL/min/1.73 m2), and according to albuminuria (A1: UACR < 30 mg/g, A2: 30-300 mg/g, A3: > 300 mg/g). Echocardiograms were analysed for left ventricular (LV) mass index (LVMi), LV ejection fraction (LVEF), and global strain measures. In adjusted analysis, eGFR groups were adjusted for confounders and albuminuria category, while albuminuria groups were adjusted for confounders and GFR category. The study population consisted of 662 outpatients with CKD and 169 controls. Mean age was 57 ± 13 years, and 61% were males. Mean LVEF and global longitudinal strain (GLS) were increasingly impaired across eGFR groups: LVEF = 60.1%, 58.4%, and 57.8% (p = 0.013), GLS =  - 16.1%, - 14.8%, and - 14.6% (p < 0.0001) for G1 + 2, G3, and G4 + 5. LVMi and prevalence of LV hypertrophy increased with albuminuria severity: mean LVMi = 87.9 g/m2, 88.1 g/m2, and 92.1 g/m2 (p = 0.007) from A1-3. Adjusted analysis confirmed reduced LVEF in G3 compared with G1 + 2, and increased LVMi in A3 compared with A1. Increasingly impaired eGFR was associated with adverse changes in LV systolic function, while albuminuria was associated with adverse changes in LV mass assessed by 3DE. Their associations were independent of each other.

An Optimized Model of Hypertrophic Preconditioning Confers Cardioprotection in the Mouse

BACKGROUND

Conventional models of hypertrophic preconditioning (C-HP) can be established surgically through transverse aortic constriction (TAC) → deconstriction (De-TAC) → reconstriction (Re-TAC) characterized by dynamic afterload while it exerts technical difficulty on operators and poses high mortality during perioperative period in mice. We aimed to introduce an optimized method for obtaining a hypertrophic preconditioning (O-HP) model for further study on cardiac hypertrophy.

METHODS

Ninety mice were divided into four groups: sham, TAC, C-HP, and O-HP. The sham group was exerted on three-time thoracotomies. The TAC group experienced twice thoracotomies and one TAC operation. C-HP and O-HP groups were given TAC, De-TAC, and Re-TAC operation at day 0, day 3, and day 7 in conventional and optimized method, respectively. We optimized the operating procedure in O-HP mice compared with the C-HP group by (1) leaving a ∼3-cm suture fixed in the subcutaneous layer after aortic constriction in TAC surgery (2) using two small forceps to untie the constriction knot instead of cutting it in the De-TAC operation. Ultrasound biomicroscopy was used for hemodynamics and cardiac function detection. Four weeks after the third surgery, all mice were sacrificed and pathology was analyzed among four groups.

RESULTS

Four weeks after Re-TAC, the survival of O-HP mice was 63.3% while that of C-HP was 26.7%. Ultrasound biomicroscopy showed a successful establishment of HP models. C-HP and O-HP mice had improved cardiac structure and function indicated by left ventricular end-systolic diameter, left ventricular end-systolic posterior wall thickness, left ventricular ejection fraction, and left ventricular fractional shortening than the TAC group. Pathological analysis showed O-HP as well as C-HP had less hypertrophy than the TAC mice.

CONCLUSIONS

Our results provide a rapid, safe, efficient, and reproducible method for optimized establishment of the HP model, which will facilitate studies for early intervention and prevention of left ventricular hypertrophy and heart failure.

Acute and Long-Term Effects of Aortic Compliance Decrease on Central Hemodynamics: A Modeling Analysis

Aortic compliance is an important determinant of cardiac afterload and a contributor to cardiovascular morbidity. In the present study, we sought to provide in silico insights into the acute as well as long-term effects of aortic compliance decrease on central hemodynamics. To that aim, we used a mathematical model of the cardiovascular system to simulate the hemodynamics (a) of a healthy young adult (baseline), (b) acutely after banding of the proximal aorta, (c) after the heart remodeled itself to match the increased afterload. The simulated pressure and flow waves were used for subsequent wave separation analysis. Aortic banding induced hypertension (SBP 106 mmHg at baseline versus 152 mmHg after banding), which was sustained after left ventricular (LV) remodeling. The main mechanism that drove hypertension was the enhancement of the forward wave, which became even more significant after LV remodeling (forward amplitude 30 mmHg at baseline versus 60 mmHg acutely after banding versus 64 mmHg after remodeling). Accordingly, the forward wave’s contribution to the total pulse pressure increased throughout this process, while the reflection coefficient acutely decreased and then remained roughly constant. Finally, LV remodeling was accompanied by a decrease in augmentation index (AIx 13% acutely after banding versus −3% after remodeling) and a change of the central pressure wave phenotype from the characteristic Type A (“old”) to Type C (“young”) phenotype. These findings provide valuable insights into the mechanisms of hypertension and provoke us to reconsider our understanding of AIx as a solely arterial parameter.

NOX5-induced uncoupling of endothelial NO synthase is a causal mechanism and theragnostic target of an age-related hypertension endotype

Hypertension is the most important cause of death and disability in the elderly. In 9 out of 10 cases, the molecular cause, however, is unknown. One mechanistic hypothesis involves impaired endothelium-dependent vasodilation through reactive oxygen species (ROS) formation. Indeed, ROS forming NADPH oxidase (Nox) genes associate with hypertension, yet target validation has been negative. We re-investigate this association by molecular network analysis and identify NOX5, not present in rodents, as a sole neighbor to human vasodilatory endothelial nitric oxide (NO) signaling. In hypertensive patients, endothelial microparticles indeed contained higher levels of NOX5—but not NOX1, NOX2, or NOX4—with a bimodal distribution correlating with disease severity. Mechanistically, mice expressing human Nox5 in endothelial cells developed—upon aging—severe systolic hypertension and impaired endothelium-dependent vasodilation due to uncoupled NO synthase (NOS). We conclude that NOX5-induced uncoupling of endothelial NOS is a causal mechanism and theragnostic target of an age-related hypertension endotype. Nox5 knock-in (KI) mice represent the first mechanism-based animal model of hypertension.

The causes of hypertension are not understood; treatments are symptomatic and prevent only few of the associated risks. This study applies network medicine to identify a subgroup of patients with NADPH oxidase 5-induced uncoupling of nitric oxide synthase as the cause of age-related hypertension, enabling a first-in-class mechanism-based treatment of hypertension.

Protective Effect of Vitis labrusca Leaves Extract on Cardiovascular Dysfunction through HMGB1-TLR4-NFκB Signaling in Spontaneously Hypertensive Rats

The Vitis labrusca is a grapevine that has antioxidant, neuroprotective, hepatoprotective, and anticarcinogenic activity. However, the effect of Vitis labrusca leaves on the cardiovascular system is yet to be ascertained. The present study was designed to investigate the effects of Vitis labrusca leaves extract (HP1) on cardiovascular remodeling in spontaneously hypertensive rats. Experiments were performed in rats and were randomly divided into the following groups: Wistar Kyoto rat (WKY), normal control group; spontaneously hypertensive rats (SHR), negative control group; SHR + Losa, positive control group (losartan, 10 mg/kg/daily, AT₁ receptor blocker) and SHR + HP1 (100 mg/kg/daily). HP1 was orally administered daily for 4 weeks. The HP1 treatment significantly improved blood pressure, electrocardiographic parameters, and echocardiogram parameters compared to hypertensive rats. Additionally, the left ventricular (LV) remodeling and LV dysfunction were significantly improved in HP1-treated hypertensive rats. Furthermore, an increase in fibrotic area has been observed in hypertensive rats compared with WKY. However, administration of HP1 significantly attenuated cardiac fibrosis in hypertensive rats. Moreover, HP1 suppressed the expression of high mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), receptor for advanced glycation end products (RAGE), and extracellular signal-regulated kinases (ERK1/2) induced by hypertensive rats, resulting in improved vascular remodeling. Therefore, these results suggest that HP1 can improve the cardiovascular remodeling in hypertensive rats, and the mechanisms may be related to the suppressive effect of HP1 on HMGB1-TLR4-NFκB signaling in the cardiovascular system. Thus, the protective role of the traditional herbal medicine HP1 may provide new insights into the development of therapeutic drugs on the development of hypertensive cardiovascular dysfunction.

Extract of Plantago asiatica L. Seeds Ameliorates Hypertension in Spontaneously Hypertensive Rats by Inhibition of Angiotensin Converting Enzyme

Plantago asiatica L. seeds is a common folk medicine with a long history of medical use in China because of its antipyretic, diuretic, and expectorant properties. It has been applied to treat hypertension clinically due to its diuresis, however, its efficacy and mechanisms on anti-hypertension has not been reported yet to our knowledge. In this study, we investigated the antihypertensive effect and underlying mechanisms of P. asiatica L. seeds extract (PASE) in spontaneously hypertensive rat (SHR). Male SHRs were treated with 2.5 mg/kg of fosinopril (FOS) and 400 mg/kg of PASE orally per day for once or 12 weeks. SHR or Wistar-Kyoto rats (WKY) receiving vehicle (distilled water) was used as control. The results demonstrated systolic, diastolic, and mean blood pressures (SBP, DBP, and MBP) were significantly lowered after single and long-term intragastric administration of PASE. The cardiac and aortic index and collagen accumulation were improved in the PASE group compared with the SHRs group. Meanwhile, PASE treatment remarkably reduced urine total protein, the ratio of serum urea nitrogen to serum creatinine, and increased serum potassium. The levels of serum angiotensin I (Ang I), angiotensin II (Ang II), the ratio of Ang II to Ang I, and aldosterone (ALD) were lowered after treatment of PASE. Besides, PASE and its major active constituents of phenylethanoid glycosides, including isoacteoside, plantamajoside and acteoside, were found to effectively inhibit angiotensin-converting enzyme (ACE) activation in vitro. These findings suggest that PASE has the antihypertensive effect that may involve a mechanism of ACE inhibition and simultaneously protect organ damage against hypertension.

Human energy expenditure: advances in organ-tissue prediction models

Humans expend energy at rest (REE), and this major energy exchange component is now usually estimated using statistical equations that include weight and other predictor variables. While these formulas are useful in evaluating an individual's or group's REE, an important gap remains: available statistical models are inadequate for explaining underlying organ-specific and tissue-specific mechanisms accounting for resting heat production. The lack of such systems level REE prediction models leaves many research questions unanswered. A potential approach that can fill this gap began with investigators who first showed in animals and later in humans that REE reflects the summated heat production rates of individual organs and tissues. Today, using advanced imaging technologies, REE can be accurately estimated from the measured in vivo mass of 10 organ-tissue mass components combined with their respective mass-specific metabolic rates. This review examines the next frontier of energy expenditure models and discusses how organ-tissue models have the potential not only to better predict REE but also to provide insights into how perturbations in organ mass lead to structure-function changes across other interacting organ systems. The introductory ideas advanced in this review provide a framework for future human energy expenditure modelling research.

Use of Biomarkers in the Evaluation and Treatment of Hypertensive Patients

The current definition of hypertension is based on blood pressure values, and blood pressure also drives treatment decisions, is the most important treatment monitoring tool and helps estimating risk of hypertension-related organ damage. In an era of precision medicine, additional biomarkers are needed in the diagnosis and management of patients with hypertension. In this review, we outline the areas in which functional, imaging and circulating biomarkers could help in a more individualised definition of hypertension and associated risk. We will cover biomarkers for diagnosis; of pathophysiology and prediction of hypertension; response to treatment, organ damage; and to monitor treatment. A clear focus is on the vasculature, the heart and the kidneys, whereas we see a need to further develop biomarkers of cerebral function in order to diagnose cognition deficits and monitor changes in cognition in the future to support addressing the growing burden of hypertension-associated vascular dementia.

Using Predicted Cardiovascular Disease Risk in Conjunction With Blood Pressure to Guide Antihypertensive Medication Treatment

Using cardiovascular disease (CVD) risk instead of or in addition to blood pressure (BP) to guide antihypertensive treatment is an active area of research. The purpose of this review is to provide an overview of studies that could inform this treatment paradigm. We review data from randomized trials on relative and absolute CVD risk reduction that can occur when antihypertensive treatment is guided by CVD risk. We also review population-level data on using CVD risk in conjunction with BP to guide antihypertensive treatment, the broad distribution in CVD risk for people with similar BP levels, and the use of CVD risk for guiding antihypertensive treatment among subgroups including older adults, young adults, and those with diabetes mellitus or chronic kidney disease. In addition, we review potential challenges in implementing antihypertensive treatment recommendations that incorporate CVD risk. In closing, we provide recommendations for using CVD risk in combination with BP to guide antihypertensive treatment.

Potential Therapeutic Strategies for Hypertension-Exacerbated Cardiotoxicity of Anticancer Drugs

Despite their recognized cardiotoxic effects, anthracyclines remain an essential component in many anticancer regimens due to their superior antitumor efficacy. Epidemiologic data revealed that about one-third of cancer patients have hypertension, which is the most common comorbidity in cancer registries. The purpose of this review is to assess whether anthracycline chemotherapy exacerbates cardiotoxicity in patients with hypertension. A link between hypertension comorbidity and anthracycline-induced cardiotoxicity (AIC) was first suggested in 1979. Subsequent preclinical and clinical studies have supported the notion that hypertension is a major risk factor for AIC, along with the cumulative anthracycline dosage. There are several common or overlapping pathological mechanisms in AIC and hypertension, such as oxidative stress. Current evidence supports the utility of cardioprotective modalities as adjunct treatment prior to and during anthracycline chemotherapy. Several promising cardioprotective approaches against AIC pathologies include dexrazoxane, early hypertension management, and dietary supplementation of nitrate with beetroot juice or other medicinal botanical derivatives (e.g., visnagin and Danshen), which have both antihypertensive and anti-AIC properties. Future research is warranted to further elucidate the mechanisms of hypertension and AIC comorbidity and to conduct well-controlled clinical trials for identifying effective clinical strategies to improve long-term prognoses in this subgroup of cancer patients.

Androgen receptor (AR) in cardiovascular diseases

Cardiovascular diseases (CVDs) are still the highest leading cause of death worldwide. Several risk factors have been linked to CVDs, including smoking, diabetes, hyperlipidemia, and gender among others. Sex hormones, especially the androgen and its receptor, androgen receptor (AR), have been linked to many diseases with a clear gender difference. Here, we summarize the effects of androgen/AR on CVDs, including hypertension, stroke, atherosclerosis, abdominal aortic aneurysm (AAA), myocardial hypertrophy, and heart failure, as well as the metabolic syndrome/diabetes and their impacts on CVDs. Androgen/AR signaling exacerbates hypertension, and anti-androgens may suppress hypertension. Androgen/AR signaling plays dual roles in strokes, depending on different kinds of factors; however, generally males have a higher incidence of strokes than females. Androgen and AR differentially modulate atherosclerosis. Androgen deficiency causes elevated lipid accumulation to enhance atherosclerosis; however, targeting AR in selective cells without altering serum androgen levels would suppress atherosclerosis progression. Androgen/AR signaling is crucial in AAA development and progression, and targeting androgen/AR profoundly restricts AAA progression. Men have increased cardiac hypertrophy compared with age-matched women that may be due to androgens. Finally, androgen/AR plays important roles in contributing to obesity and insulin/leptin resistance to increase the metabolic syndrome.

Computed Tomography-Derived Parameters of Myocardial Morphology and Function in Black and White Patients With Acute Chest Pain

Blacks have higher mortality and hospitalization rates because of congestive heart failure compared with white counterparts. Differences in cardiac structure and function may contribute to the racial disparity in cardiovascular outcomes. Our aim was to compare computed tomography (CT)-derived cardiac measurements between black patients with acute chest pain and age- and gender-matched white patients. We performed a retrospective analysis under an institutional review board waiver and in Health Insurance Portability and Accountability Act compliance. We investigated patients who underwent cardiac dual-source CT for acute chest pain. Myocardial mass, left ventricular (LV) ejection fraction, LV end-systolic volume, and LV end-diastolic volume were quantified using an automated analysis algorithm. Septal wall thickness and cardiac chamber diameters were manually measured. Measurements were compared by independent t test and linear regression. The study population consisted of 300 patients (150 black-mean age 54 ± 12 years; 46% men; 150 white-mean age 55 ± 11 years; 46% men). Myocardial mass was larger for blacks compared with white (176.1 ± 58.4 vs 155.9 ± 51.7 g, p = 0.002), which remained significant after adjusting for age, gender, body mass index, and hypertension. Septal wall thickness was slightly greater (11.9 ± 2.7 vs 11.2 ± 3.1 mm, p = 0.036). The LV inner diameter was moderately larger in black patients in systole (32.3 ± 9.0 vs 30.1 ± 5.4 ml, p = 0.010) and in diastole (50.1 ± 7.8 vs 48.9 ± 5.2 ml, p = 0.137), as well as LV end-diastolic volume (134.5 ± 42.7 vs 128.2 ± 30.6 ml, p = 0.143). Ejection fraction was nonsignificantly lower in blacks (67.1 ± 13.5% vs 69.0 ± 9.6%, p = 0.169). In conclusion, CT-derived myocardial mass was larger in blacks compared with whites, whereas LV functional parameters were generally not statistically different, suggesting that LV mass might be a possible contributing factor to the higher rate of cardiac events in blacks.

The septal bulge--an early echocardiographic sign in hypertensive heart disease

Patients in the early stage of hypertensive heart disease tend to have normal echocardiographic findings. The aim of this study was to investigate whether pathology-specific echocardiographic morphologic and functional parameters can help to detect subclinical hypertensive heart disease. One hundred ten consecutive patients without a history and medication for arterial hypertension (AH) or other cardiac diseases were enrolled. Standard echocardiography and two-dimensional speckle-tracking-imaging analysis were performed. Resting blood pressure (BP) measurement, cycle ergometer test (CET), and 24-hour ambulatory BP monitoring (ABPM) were conducted. Patients were referred to "septal bulge (SB)" group (basal-septal wall thickness ≥ 2 mm thicker than mid-septal wall thickness) or "no-SB" group. Echocardiographic SB was found in 48 (43.6%) of 110 patients. In this SB group, 38 (79.2%) patients showed AH either by CET or ABPM. In contrast, in the no-SB group (n = 62), 59 (95.2%) patients had no positive test for AH by CET or ABPM. When AH was solely defined by resting BP, SB was a reasonable predictive sign for AH (sensitivity 73%, specificity 76%). However, when AH was confirmed by CET or ABPM the echocardiographic SB strongly predicted clinical AH (sensitivity 93%, specificity 86%). In addition, regional myocardial deformation of the basal-septum in SB group was significantly lower than in no-SB group (14 ± 4% vs. 17 ± 4%; P < .001). In conclusion, SB is a morphologic echocardiographic sign for early hypertensive heart disease. Sophisticated BP evaluation including resting BP, ABPM, and CET should be performed in all patients with an accidental finding of a SB in echocardiography.

Left Ventricular Hypertrophy Phenotype in Childhood-Onset Essential Hypertension

The aim of this study was to determine the risk factors associated with left ventricular (LV) hypertrophy (LVH) among 89 untreated children with primary hypertension. Clinic hypertension was confirmed by 24-hour ambulatory blood pressure (BP) monitoring. LV mass (LVM) index was calculated as LVM (g)/height (m)(2.7) and LVH was defined as LVM index >95th percentile. Children with (n=32) and without (n=57) LVH were compared. Both obesity and systolic BP were independently associated with LVH, with a higher contribution by body mass index. Obesity contributed significantly, with a nearly nine-fold increased risk of LVH. There was evidence of effect modification by the presence or absence of obesity on the relationship between systolic BP and LVH, whereby the relationship existed mainly in nonobese rather than obese children. Hence, to achieve reversal of LVH, clinicians should take into account both BP control and weight management.

Evaluation of left atrial function in hypertensive patients with and without left ventricular hypertrophy using velocity vector imaging

To study left atrial deformation characteristics using Velocity vector imaging (VVI) in hypertensive patients with and without left ventricular hypertrophy (LVH), and to explore its value for detection of left atrial dysfunction in these patients. Sixty-four patients with essential hypertension were divided into normal left ventricular geometry (LVN, 37 cases) and LVH (27 cases) groups, according to their left ventricular mass index. Twenty-five age-matched healthy participants were included as control group. Two-dimensional dynamic images of the apical four- and two-chamber echocardiographic views were obtained, and strain/strain rate (SR) curves of eight atrial segments were derived by VVI software. Peak systolic strain (ε(sys)), systolic SR (SRs), early and late diastolic SR (SRe, SRa) were measured and calculated. Peak early diastolic mitral inflow and annulus velocities were also measured and their ratio (E/E') calculated. Compared with the control group, SRe decreased and SRa increased significantly in LVH group (P < 0.05), while no significant difference was found between LVN and control groups with respect to SRe, SRa, SRs and ε(sys) (P > 0.05). Also, no significant difference was observed in SRe, SRa, SRs and ε(sys) between LVH and LVN groups (P > 0.05). SRe and SRa correlated significantly with E/E' (r = -0.634, r = 0.609; both P < 0.001). Strain/SR parameters derived from VVI may reflect decreased conduit, increased booster pump function of the left atrium in hypertensive patients with LVH and correlate with left ventricular diastolic function.

Effects of hypertension and exercise on cardiac proteome remodelling

Left ventricle hypertrophy is a common outcome of pressure overload stimulus closely associated with hypertension. This process is triggered by adverse molecular signalling, gene expression, and proteome alteration. Proteomic research has revealed that several molecular targets are associated with pathologic cardiac hypertrophy, including angiotensin II, endothelin-1 and isoproterenol. Several metabolic, contractile, and stress-related proteins are shown to be altered in cardiac hypertrophy derived by hypertension. On the other hand, exercise is a nonpharmacologic agent used for hypertension treatment, where cardiac hypertrophy induced by exercise training is characterized by improvement in cardiac function and resistance against ischemic insult. Despite the scarcity of proteomic research performed with exercise, healthy and pathologic heart proteomes are shown to be modulated in a completely different way. Hence, the altered proteome induced by exercise is mostly associated with cardioprotective aspects such as contractile and metabolic improvement and physiologic cardiac hypertrophy. The present review, therefore, describes relevant studies involving the molecular characteristics and alterations from hypertensive-induced and exercise-induced hypertrophy, as well as the main proteomic research performed in this field. Furthermore, proteomic research into the effect of hypertension on other target-demerged organs is examined.

Burden of rare sarcomere gene variants in the Framingham and Jackson Heart Study cohorts

Rare sarcomere protein variants cause dominant hypertrophic and dilated cardiomyopathies. To evaluate whether allelic variants in eight sarcomere genes are associated with cardiac morphology and function in the community, we sequenced 3,600 individuals from the Framingham Heart Study (FHS) and Jackson Heart Study (JHS) cohorts. Out of the total, 11.2% of individuals had one or more rare nonsynonymous sarcomere variants. The prevalence of likely pathogenic sarcomere variants was 0.6%, twice the previous estimates; however, only four of the 22 individuals had clinical manifestations of hypertrophic cardiomyopathy. Rare sarcomere variants were associated with an increased risk for adverse cardiovascular events (hazard ratio: 2.3) in the FHS cohort, suggesting that cardiovascular risk assessment in the general population can benefit from rare variant analysis.

Obstructive sleep apnea in incremental hemodialysis: determinants, consequences, and impact on survival

Sleep disorders are common in hemodialysis patients, although causes and consequences remain unclear. We sought to establish prevalence, determinants, and outcomes of sleep disturbances in patients receiving incremental dialysis. One hundred two unselected patients undergoing incremental high-flux hemodialysis or hemodiafiltration underwent limited overnight sleep study. Large subsets underwent echocardiography, interdialytic ambulatory blood pressure monitoring, and brain natriuretic peptide measurements. Patients were followed up to 44 months. Full sleep data were obtained in 91 patients. All had sleep disturbance as evidenced by an apnea-hypopnea index >5/min. We defined major obstructive sleep apnea (MOSA) as an apnea-hypopnea index ≥ 15, together with either significant oxygen desaturation or symptoms of daytime sleepiness. Forty patients met these criteria. Significant independent predictors of MOSA were age <65 years, male gender, has diabetes, and has a brain natriuretic peptide >2500 pg/mL. Mean ambulatory blood pressure and left ventricular mass index were significantly higher in these patients. In a model controlling for body mass index, high C-reactive protein, and the presence of cancer, MOSA was associated with a twofold increased risk of mortality, although this did not reach statistical significance. MOSA was common, and was associated with hypertension and high left ventricular mass index. Whether obstructive sleep apnea contributes to the high mortality remains to be firmly established.

Elevation of plasma homocysteine by methionine loading increases the diastolic blood pressure response to exercise

OBJECTIVE

Exercise blood pressure is elevated in conditions associated with endothelial dysfunction. To determine whether this is a causal association, we examined the effects of endothelial dysfunction induced by methionine loading, on exercise blood pressure.

DESIGN

Healthy subjects (18-63 years) participated in randomized, double-blind, cross-over studies receiving methionine and placebo on separate occasions before exercise.

METHODS

In study 1 (n = 32), subjects received placebo and methionine 100 mg/kg 4 h before exercise and, in study 2 (n = 11), placebo and methionine 200 mg/kg (given as 100 mg 20 and 12 h before exercise). A further study confirmed that methionine 100 mg/kg impaired brachial artery flow-mediated dilation. Blood pressure was measured by mercury sphygmomanometry at rest and during low workload bicycle ergometry.

RESULTS

Plasma homocysteine increased after methionine compared to placebo (22.5 +/- 1.2 versus 7.7 +/- 0.7 mumol/l in study 1, and 50.2 +/- 7.6 versus 12.8 +/- 0.7 mumol/l in study 2, means +/- SE, each P < 0.0001). In both studies resting systolic and diastolic blood pressures and the increases in systolic blood pressure during exercise were similar after methionine and placebo. By contrast, exercise diastolic blood pressure responses (measured as the change from resting values) increased more after methionine than after placebo. In study 1, diastolic blood pressure responses increased relative to placebo by 3.5 +/- 1.0, 3.7 +/- 1.0 and 2.4 +/- 1.0 mmHg at 50, 75 and 100 W, respectively (P < 0.01). In study 2, diastolic blood pressure responses increased by 4.9 +/- 1.0, 5.4 +/- 2.1 and 6.1 +/- 1.1 mmHg at 50, 75 and 100 W, respectively (P < 0.001).

CONCLUSION

Endothelial dysfunction produced by methionine loading is associated with an increased exercise diastolic blood pressure response.

Heart Failure in Women

The incidence of congestive heart failure in the US population is increasing as more women and men survive with chronic hypertensive and atherosclerotic heart disease. Almost half the patients in the US with heart failure are women. Hypertension, diabetes mellitus, and cigarette smoking are all more potent risk factors for the development of heart failure in women than in men. Important differences in presentation and mortality explain gender differences in the clinical course of heart failure. Overall mortality is lower for women than for men with symptomatic heart failure. Some but not all of this difference can be explained by a lower rate of ischemic heart disease. Standard treatments for congestive heart failure, including angiotensin converting enzyme inhibitors and beta-blockers, have been shown to be equally efficacious in men and in women. Preliminary data on angiotensin II receptor blockers suggests equivalent benefit with further trial data awaited. Peripartum cardiomyopathy is a form of heart failure unique to women, occurring in the last stages of pregnancy or within 5 months after delivery. Approximately half of affected women regain normal ventricular function but for those who do not, the risk of recurrent symptomatic heart failure and mortality during subsequent pregnancies is high.

Heart failure in women

Heart failure affects more than 5 million Americans. Each year, about 400,000 individuals develop heart failure, making it the nation's most rapidly growing cardiac problem. Almost one third of these individuals have New York Heart Association Functional Class III or IV heart failure and are faced with progressive clinical deterioration and frequent hospital admissions. These figures will continue to escalate as the population ages. The success of interventional procedures and pharmacologic therapies in the management of coronary artery disease has enabled this population to survive acute events, at the same time creating a population with chronic disease. Common etiologies of heart failure in women include coronary artery disease, myocardial infarction, and valvular disease. However, women are at especially high risk for developing heart failure due to diastolic dysfunction associated with hypertension and diabetes. Heart failure in women is best managed across the care continuum, incorporating pharmacologic agents, interventional procedures when appropriate, dietary restrictions, self-monitoring, and psychosocial support. Much of the recent literature has focused on women and heart disease. This emphasis is partly due to public misconception about women's health problems and the growing body of research distinguishing gender differences. Significant advances in therapy have been made to improve the quality and span of life for people with heart disease. Despite therapeutic advances, however, women have high mortality rates from heart disease, including heart failure due to ischemic causes. In fact, women with heart failure present differently than men and have different etiologies and treatment options. As we learn more about women and heart disease, the distinguishing differences unfold and become helpful in establishing a plan of care.

Gender-differences in myocardial adaptation to afterload in normotensive and hypertensive rats

Echocardiographic studies suggest that women appear to exhibit a greater degree of myocardial hypertrophy in response to increased afterload than men. Therefore, gender differences and the role of estrogen and testosterone in the development of myocardial hypertrophy were studied in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Male and female rats were either surgically neutered or underwent a sham operation at 21 days of age. A subgroup of neutered females of each strain received 17beta-estradiol replacement. At 6 months, the heart weight-to-body weight ratio was assessed and correlated with systemic blood pressure. Compared with males, females had significantly smaller body and heart weights in both normotensive and hypertensive strains. Despite this, females consistently had significantly greater heart weight-to-body weight ratios. In females, neutering significantly lowered the heart weight-to-body weight ratio in WKY rats, which was returned to intact levels with estrogen replacement. Female SHR showed similar, but not statistically significant, responses. In males, neutering appeared to result in a higher heart weight-to-body weight ratio in WKY rats, but the opposite was seen in SHR. In addition, there was a significant correlation between arterial blood pressure and heart weight-to-body weight ratio (systolic r=0.45, P=0.0015: diastolic r=0.52, P=0.0002) in intact males and females of both strains, and for a given diastolic pressure, females always exhibited a greater heart weight-to-body weight ratio than males. Thus, a greater degree of myocardial hypertrophy in females appears to be related to the presence of estrogen in both normotensive and hypertensive rats. Females show a stronger relationship between heart/body weight and blood pressure than males, which occurred independent of the presence of estrogen.

Association of fasting blood sugar level, insulin level, and obesity with left ventricular mass in healthy children and adolescents: The Bogalusa Heart Study

BACKGROUND

Insulin resistance, often associated with obesity, is hypothesized to be involved in the pathogenesis of essential hypertension and may relate to increased left ventricular mass (LVM).

METHODS

We examined correlations between echocardiographic LVM and fasting blood glucose and insulin levels in a cross-section of 216 black and white healthy children and young adults aged 13 to 27 years in Bogalusa, Louisiana. Anthropometric measurements and blood pressure readings were also obtained.

RESULTS

Positive bivariate correlation was found between fasting blood glucose level and LVM corrected for growth (LVMC) (LVMC = LVM/Height2.7) with all race/sex groups combined (r = 0.17, P Collapse

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MESH Headings

• Adolescent
• Adult
• Black People
• Blood Glucose/metabolism
• Cross-Sectional Studies
• Echocardiography
• Fasting
• Female
• Heart Ventricles/diagnostic imaging
• Heart Ventricles/pathology
• Humans
• Illinois
• Insulin/blood
• Louisiana
• Male
• Multivariate Analysis
• Obesity/blood
• Obesity/ethnology
• Obesity/pathology
• White People
• Black or African American

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Grants

• 5R01 HL38844 NHLBI NIH HHS

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Affiliation(s)

E M Urbina Tulane Center for Cardiovascular Health, New Orleans, LA 70112-7103, USA
S S Gidding
W Bao
A Elkasabany
G S Berenson

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Left ventricular mass index increase in early renal disease: impact of decline in hemoglobin

Cardiovascular disease occurs in patients with progressive renal disease both before and after the initiation of dialysis. Left ventricular hypertrophy (LVH) is an independent predictor of morbidity and mortality in dialysis populations and is common in the renal insufficiency population. LVH is associated with numerous modifiable risk factors, but little is known about LV growth (LVG) in mild-to-moderate renal insufficiency. This prospective multicenter Canadian cohort study identifies factors associated with LVG, measured using two-dimensional-targeted M-mode echocardiography. Eight centers enrolled 446 patients, 318 of whom had protocol-mandated clinical, laboratory, and echocardiographic measurements recorded. We report 246 patients with assessable echocardiograms at both baseline and 12 months with an overall prevalence of LVH of 36%. LV mass index (LVMI) increased significantly (>20% of baseline or >20 g/m2) from baseline to 12 months in 25% of the population. Other than baseline LVMI, no differences in baseline variables were noted between patients with and without LVG. However, there were significant differences in decline of Hgb level (-0.854 v -0.108 g/dL; P = 0.0001) and change in systolic blood pressure (+6.50 v -1.09 mm Hg; P = 0.03) between the groups with and without LVG. Multivariate analysis showed the independent contribution of decrease in Hgb level (odds ratio [OR], 1.32 for each 0.5-g/dL decrease; P = 0.004), increase in systolic blood pressure (OR, 1.11 for each 5-mm Hg increase; P = 0.01), and lower baseline LVMI (OR, 0.85 for each 10-g/m2; P = 0.011) in predicting LVG. Thus, after adjusting for baseline LVMI, Hgb level and systolic blood pressure remain independently important predictors of LVG. We defined the important modifiable risk factors. There remains a critical need to establish optimal therapeutic strategies and targets to improve clinical outcomes.

Gender differences in survival in advanced heart failure. Insights from the FIRST study

BACKGROUND

Previous natural history studies in broad populations of heart failure patients have associated female gender with improved survival, particularly in patients with a nonischemic etiology of ventricular dysfunction. This study investigates whether a similar survival advantage for women would be evident among patients with advanced heart failure.

METHODS AND RESULTS

The study analysis is based on the Flolan International Randomized Survival Trial (FIRST) study which enrolled 471 patients (359 men and 112 women) who had evidence of end-stage heart failure with marked symptoms (60% NYHA class IV) and severe left ventricular dysfunction (left ventricular ejection fraction 18+/-4.9%). A Cox proportional-hazards model, adjusted for age, gender, 6-minute walk, dobutamine use at randomization, mean pulmonary artery blood pressure, and treatment assignment, showed a significant association between female gender and better survival (relative risk of death for men versus women was 2.18, 95% CI 1.39 to 3.41; P<0.001). Although formal interaction testing was negative (P=0.275), among patients with a nonischemic etiology of heart failure, the relative risk of death for men versus women was 3.08 (95% CI 1.56 to 6.09, P=0.001), whereas among those with ischemic heart disease, the relative risk of death for men versus women was 1.64 (95% CI 0.87 to 3.09, P=0.127).

CONCLUSIONS

Women with advanced heart failure appear to have better survival than men. Subgroup analysis suggests this finding is strongest among patients with a nonischemic etiology of heart failure.

ACE inhibitors and regression of left ventricular hypertrophy

Left ventricular hypertrophy (LVH) is a common condition and a powerful independent risk factor for coronary heart disease, congestive heart failure, and other cardiac morbidity. It is associated with the male sex and advancing age. Its most common cause is hypertension, and many antihypertensive agents induce regression of LVH. Angiotensin-converting enzyme (ACE) inhibitors have been shown to reverse LVH by a mechanism as yet unknown. Reduction in afterload and other hemodynamic abnormalities by reduction of blood pressure is clearly a factor, but ACE inhibitors also block adrenergic action and other sympathetic nervous system influences, and the reduction in angiotensin II produces many effects. By inhibiting this potent vasoconstrictor and suppressing its degradation of the powerful vasodilator bradykinin, and by promoting sodium and water excretion, ACE inhibitors contribute to the restoration of normal ventricular function. Angiotensin II promotes protein synthesis in myocardial myocytes, and blocking this action may arrest the hypertrophic process. To determine the effect of angiotensin II on LVH and normalization of LV function, a study is now underway evaluating the effects of lisinopril, a new lysine analog of enalapril, and a diuretic agent in the treatment of hypertension LVH.

Hypertension and ST segment depression during ambulatory electrocardiographic recording. Results from the prospective population study 'men born in 1914' from Malmö, Sweden

The aim of this study in 341 men (aged 68 years) without history of ischemic heart disease was to study the relation between hypertension and silent ischemic-type ST segment depression during ambulatory long-term electrocardiographic recording and to assess the influence between these two variables on cardiovascular morbidity and mortality rates. Seventy-nine men (23%) demonstrated one or more episodes of silent ischemic ST segment depression. One hundred and sixty-seven men (49%) were considered to have hypertension (i.e., they had a diastolic blood pressure of 95 mm Hg or greater or were treated with antihypertensive therapy). Forty-nine (72%) of the 68 treated hypertensive subjects were classified as uncontrolled (i.e., their diastolic blood pressure was 95 mm Hg or greater). The occurrence of ischemic ST depression was higher in hypertensive men (28%) than in normotensive men (19%). The highest incidence of ischemic ST depression (41%) was observed in treated hypertensive men with inadequate blood pressure control. Cardiac event rate during a 53-month follow-up was 6.6% in hypertensive men and 4.6% in normotensive men. Uncontrolled treated hypertensive men had a higher event rate (14%) than hypertensive men overall. Hypertensive men with inadequate blood pressure control and who demonstrated ST segment depression had the highest event rate (25%).

Regression of left ventricular mass in systemic hypertension

The importance of treatment in systemic hypertension and cardiovascular morbidity and mortality has been established. Although systemic hypertension is the most important factor in the pathogenesis of left ventricular hypertrophy, other factors such as catecholamines and renin-angiotensin system may be involved. Increased left ventricular mass causes reduction in coronary reserve and may lead to acute ischemic events. Equally efficacious antihypertensive agents may have diverse effects on left ventricular hypertrophy and left ventricular function. New tomographic techniques with improved spatial resolution are emerging in the evaluation of left ventricular mass and may therefore provide better assessment of changes in left ventricular mass. With improved measures of left ventricular mass the question as to whether regression of left ventricular mass provides an additional benefit beyond control of blood pressure in hypertensive individuals may be finally answered.

Upward shift of the lower range of coronary flow autoregulation in hypertensive patients with hypertrophy of the left ventricle

BACKGROUND

At any given perfusion pressure, coronary reserve is expressed by the difference between autoregulated and maximally vasodilated flow. In hypertension the raised coronary resistance reduces the steepness of the pressure-flow relationship at maximal vasodilatation. In the presence of cardiac hypertrophy the line of autoregulated flow becomes higher. For these reasons coronary reserve is reduced and the point at which baseline flow approaches the maximal achievable flow might be shifted to a higher perfusion pressure. Thus, any reduction below this elevated and critical value of pressure would lower the coronary flow.

METHODS AND RESULTS

The investigated patients were normotensive (controls, nine) and hypertensive with normal (group I, seven) or augmented LV mass index because of concentric LV hypertrophy (group II, eight). All had effort-induced angina and angiographically normal left epicardial branches. Flow in the great cardiac vein was measured by thermodilution in the baseline and during stepwise (5 mm Hg every 5 minutes) decrease of the coronary perfusion pressure with a titrated nitroprusside i.v. infusion; perfusion pressures of 60 mm Hg in the controls and 70 mm Hg in the hypertensives were taken as end points. Baseline flow averaged 102 ml/min in normotensives, 104 ml/min in hypertensive group I and 148 ml/min in hypertensive group II. At the end points flow was similar to baseline in the controls and group I. In group II coronary flow started to decline and myocardial O2 extraction started to slightly but significantly rise at perfusion pressures of 90-80 mm Hg; at the end point flow was reduced by 26% (p less than 0.01 from baseline). The perfusion patterns did not seem to be related to the changes in tension-time index and heart rate.

CONCLUSIONS

The association of high blood pressure (reduced ability of the coronary arterioles to dilate) and hypertrophy of the myocardium (augmented baseline coronary flow) may shift the point of exhaustion of coronary reserve to a higher perfusion pressure and make the myocardium vulnerable to treatment-induced relative hypertension.

Determinants of cardiac involvement in children and adolescents with essential hypertension

Left ventricular hypertrophy is often found in association with systemic hypertension and may be an independent risk factor for cardiovascular disease morbidity and mortality. Few studies have investigated the determinants of left ventricular mass (LVM) in young patients with essential hypertension. Therefore, we studied 104 children and adolescents with blood pressure persistently greater than the 90th percentile for age and sex and with no known cause of blood pressure elevation. LVM was determined by echocardiography and was indexed by height to account for body size. The mean LVM index was 90.2 +/- 26.0 g/m. Using the gender-specific 95th percentile from normal children, 40 subjects (38.5%) had left ventricular hypertrophy. Using multiple regression analysis, the significant independent direct correlates of LVM index were male sex, body mass index, dietary sodium intake, age at diagnosis, and systolic blood pressure at maximum exercise. The significant independent inverse correlate of LVM index was resting heart rate (p less than 0.05). These variables accounted for a substantial portion of the LVM index variance in this population (multiple R2 = 0.56, p less than 0.001). The results indicate that left ventricular hypertrophy is prevalent in children and adolescents with essential hypertension. The direct association of LVM index with body mass index and dietary sodium intake suggests weight reduction and dietary salt restriction might be useful to prevent or treat the development of left ventricular hypertrophy in pediatric patients with essential hypertension.

Essential hypertension in blacks: epidemiology, characteristics, and possible roles of racial differences in sodium, potassium, and calcium regulation

Racial differences in the regulation of Na+, K+, and Ca2+ have been shown both at the systemic and cellular levels. These include a higher incidence of "salt sensitivity," lower urinary K+ excretion, lower plasma renin activity, and higher circulating levels of immunoreactive parathyroid hormone and 1.25 dihydroxyvitamin D in blacks than in whites. Blacks exhibit a higher erythrocyte Na+ concentration, coupled with a lower maximal initial reaction velocity of erythrocyte Na,K-ATPase. Blacks also appear to differ from whites in erythrocyte Na+, K+ cotransport and Na-Li countertransport. Moreover, they show a higher activity of the Na(+)-H+ antiport in skin fibroblasts and a greater response of cellular Ca2+ signaling to agonists in serum. Mechanisms linking some of these racial differences in ionic metabolism to the increased propensity of blacks to develop essential hypertension are proposed, and the epidemiology and characteristics of this disease in blacks are reviewed.

Circadian blood pressure changes and left ventricular hypertrophy in essential hypertension

The effects of circadian blood pressure (BP) changes on the echocardiographic parameters of left ventricular (LV) hypertrophy were investigated in 235 consecutive subjects (137 unselected untreated patients with essential hypertension and 98 healthy normotensive subjects) who underwent 24-hour noninvasive ambulatory blood pressure monitoring (ABPM) and cross-sectional and M-mode echocardiography. In the hypertensive group, LV mass index correlated with nighttime (8:00 PM to 6:00 AM) systolic (r = 0.51) and diastolic (r = 0.35) blood pressure more closely than with daytime (6:00 AM to 8:00 PM) systolic (r = 0.38) and diastolic (r = 0.20) BP, or with casual systolic (r = 0.33) and diastolic (r = 0.27) BP. Hypertensive patients were divided into two groups by presence (group 1) and absence (group 2) of a reduction of both systolic and diastolic BP during the night by an average of more than 10% of the daytime pressure. Casual BP, ambulatory daytime systolic and diastolic BP, sex, body surface area, duration of hypertension, prevalence of diabetes, quantity of sleep during monitoring, funduscopic changes, and serum creatinine did not differ between the two groups. LV mass index, after adjustment for the age, the sex, the height, and the daytime BP differences between the two groups (analysis of covariance) was 82.4 g/m2 in the normotensive patient group, 83.5 g/m2 in hypertensive patients of group 1 and 98.3 g/m2 in hypertensive patients of group 2 (normotensive patients vs. group 1, p = NS; group 1 vs. group 2, p = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Recommendations concerning use of echocardiography in hypertension and general population research

Use of echocardiography to quantify left ventricular structure and function requires standardization of recording conditions and techniques, accurate machine calibration, and definition of requirements for measurable images. Measurement of left ventricular muscle mass should use M-mode, two-dimensional, or three-dimensional echocardiographic methods that have been anatomically validated to maximize accuracy and comparability of results among studies. Body size and sex influence ventricular muscle mass sufficiently to be taken into account for clinical and research purposes, while age and physical activity are of less certain importance. Echocardiographic studies have clarified the prevalence of left ventricular hypertrophy in hypertensive patients and the effect of blood pressure during normal activity on left ventricular muscle mass, and they have provided data suggesting that left ventricular hypertrophy is a major cardiac risk factor in hypertensive and general populations. Further research is needed to obtain definitive results in these areas, to track the hitherto elusive transition from functionally compensated cardiac hypertrophy to congestive heart failure, and to determine the degree and selectivity of beneficial cardiac effects of antihypertensive treatment. Three-dimensional echocardiographic reconstruction and Doppler measurement of intracardiac blood flow and systemic hemodynamics are likely to extend the usefulness of echocardiography for hypertension and general population research.