Fosca Quarti Trevano

Long-Term Prognostic Value of Blood Pressure Variability in the General Population. Results of the Pressioni Arteriose Monitorate e Loro Associazioni Study

The hypothesis has been advanced that cardiovascular prognosis is related not only to 24-hour mean blood pressure but also to blood pressure variability. Data, however, are inconsistent, and no long-term prognostic study is available. In 2012 individuals randomly selected from the population of Monza (Milan), 24-hour ambulatory blood pressure (Spacelabs 90207) was measured via readings spaced by 20 minutes. Systolic and diastolic blood pressure variability was obtained by calculating the following: (1) the SD of 24-hour, day, and night mean values; (2) the day–night blood pressure difference; and (3) the residual or erratic blood pressure variability (Fourier spectral analysis). Fatal cardiovascular and noncardiovascular events were registered for 148 months. When adjusted for age, sex, 24-hour mean blood pressure, and other risk factors, there was no relationship between the risk of death and 24-hour, day, and night blood pressure SDs. In contrast, the adjusted risk of cardiovascular death was inversely related to day–night diastolic BP difference (&bgr; coefficient=−0.040; P<0.02) and showed a significant positive relationship with residual diastolic blood pressure variability (&bgr; coefficient=0.175; P<0.002). Twenty-four–hour mean blood pressure attenuation of nocturnal hypotension and erratic diastolic blood pressure variability all independently predicted the mortality risk, with the erratic variability being the most important factor. Our data show that the relationship of blood pressure to prognosis is complex and that phenomena other than 24-hour mean values are involved. They also provide the first evidence that short-term erratic components of blood pressure variability play a prognostic role, with their increase being accompanied by an increased cardiovascular risk.

Effect of central and peripheral body fat distribution on sympathetic and baroreflex function in obese normotensives

Background Previous studies have shown that obesity is characterized by a sympathetic overactivity coupled with an insulin resistance state and a baroreflex impairment. The present study was set out to compare the effects of peripheral versus central obesity on sympathetic, metabolic and reflex function. Methods In 36 lean subjects (age 35.8 ± 1.4 years, mean ± SEM), 20 subjects with peripheral obesity (PO) and 26 subjects with central obesity (CO), all age-matched and with normal blood pressure values, we measured beat-to-beat arterial blood pressure (Finapres), heart rate (HR, ECG), homeostasis model assessment (HOMA) index, plasma norepinephrine (NE, high-performance liquid chromatography) and postganglionic muscle sympathetic nerve traffic (MSNA, microneurography) at rest and during baroreceptor stimulation and deactivation induced by stepwise intravenous infusions of phenylephrine and nitroprusside, respectively. Results Both HOMA index, NE and MSNA values were significantly increased (P < 0.01) in obese as compared with lean individuals. Subjects with CO displayed MSNA and HOMA values significantly greater than those found in individuals with PO (65.4 ± 2.0 versus 47.9 ± 1.9 bs/100hb and 2.85 ± 0.10 versus 2.43 ± 0.11 a.u., respectively, P < 0.05 for both). Both in male and female subjects with CO or PO, MSNA, HOMA index and waist-to-hip ratio were significantly related to each other. Baroreceptor-HR and -MSNA control was significantly (P < 0.01) impaired in obese as compared with lean subjects, the degree of impairment being similar in CO and PO. Conclusions These data suggest that CO is characterized by a sympathetic activation greater for magnitude than that detectable in PO. This appears not to be related to gender or to baroreflex mechanisms but rather to metabolic factors, i.e. to the greater insulin resistance characterizing CO.

Comparative effects of candesartan and hydrochlorothiazide on blood pressure, insulin sensitivity, and sympathetic drive in obese hypertensive individuals: Results of the CROSS study

Objective The increase in blood pressure that accompanies the obese state is almost invariably associated with alterations in metabolism (insulin resistance and dyslipidaemia) and the neurohumoral profile (activation of the renin–angiotensin system, sympathetic overactivity), which potentiate the cardiovascular risk associated with hypertension. However, debate remains as to the antihypertensive drug on which treatment of obesity-related hypertension should be based. The CROSS (Candesartan Role on Obesity and on Sympathetic System) study was undertaken to examine the antihypertensive, neuroadrenergic, and metabolic effects of an angiotensin II receptor blocker in comparison with a diuretic in obese hypertensive individuals. Methods In 127 obese hypertensive individuals aged 50.7 ± 5.1 years (mean ± SD), we measured clinic blood pressure, heart rate, plasma glucose, and insulin at rest and during an oral glucose load before and 12 weeks after treatment with either candesartan cilexetil (8–16 mg once daily) or hydrochlorothiazide (HCTZ, 25–50 mg once daily), administered orally in accordance with a double-blind, randomized, placebo-controlled, two-parallel-groups study design. Insulin sensitivity was expressed as insulin resistance index (IRI), calculated as the ratio of the area under the curve (AUC) for glucose to that for insulin. In a subgroup of patients, measurements also included direct microneurographic recording of muscle sympathetic nerve activity (MSNA) in the peroneal nerve. Results Candesartan cilexetil caused a significant (P < 0.01) reduction in both mean blood pressure (from 114.2 ± 5.1 to 99.6 ± 6.0 mmHg) and MSNA (from 51.0 ± 12.3 to 40.4 ± 12.5 bursts per 100 heart beats), and a significant (P < 0.02) increase in insulin sensitivity (AUC IRI: from −23.2 ± 22.1 to −17.6 ± 12.2). In contrast, HCTZ did not significantly affect MSNA and worsened insulin sensitivity, while achieving blood pressure reductions similar to those produced by candesartan cilexetil. Conclusions These data provide evidence that, in obese hypertensive individuals, treatment with candesartan cilexetil has an antihypertensive effect similar to that of HCTZ. Unlike diuretic treatment, however, treatment with candesartan cilexetil improves insulin sensitivity and exerts sympathoinhibitory effects.

Metabolic Syndrome in the Pressioni Arteriose Monitorate E Loro Associazioni (PAMELA) Study: Daily Life Blood Pressure, Cardiac Damage, and Prognosis

The prevalence of the metabolic syndrome (National Cholesterol Education Program Adult Treatment Panel III criteria) and its relationships with daily life blood pressures, cardiac damage, and prognosis were determined in 2013 subjects from a Northern Italian population aged 25 to 74 years. Home blood pressure, 24-hour blood pressure, and left ventricular mass index (echocardiography) were also measured. Cardiovascular and noncardiovascular deaths were registered over 148 months. Metabolic syndrome was found in 16.2% of the sample, an office blood pressure elevation being the most frequent (95.4%) and the blood glucose abnormality the least frequent (31.5%) component. There was in metabolic syndrome a frequent elevation in home and/or 24-hour average blood pressure, as well as a greater left ventricular mass index and prevalence of left ventricular hypertrophy, which was manifest even when data were adjusted for between-group differences, including blood pressure. The adjusted risk of cardiovascular and all-cause mortality was greater in metabolic syndrome subjects (+71.0% and +37.0%; P<0.05), a further marked increase being observed with left ventricular hypertrophy or “in-office” and “out-of-office” blood pressure elevations. The increased risk was related to the blood pressure and the blood glucose component of metabolic syndrome, with no contribution of the remaining components. Thus, metabolic syndrome is common in a Mediterranean population in which it significantly increases the long-term risk of death. Cardiac abnormalities and increases in home and 24-hour blood pressure are common in metabolic syndrome, and their occurrence further enhances the risk. The contribution of metabolic syndrome components to the risk, however, is unbalanced and mainly related to blood pressure and glucose abnormalities.

Obstructive Sleep Apnea–Dependent and –Independent Adrenergic Activation in Obesity

No agreement exists as to the mechanisms responsible for the sympathetic hyperactivity characterizing human obesity, which has been ascribed recently to a chemoreflex stimulation brought about by obstructive sleep apnea rather than to an increase in body weight, per se. In 86 middle-age normotensive subjects classified according to body mass index, waist-to-hip ratio, and apnea/hypopnea index (overnight polysomnographic evaluation) as lean and obese subjects without or with obstructive sleep apnea, we assessed via microneurography muscle sympathetic nerve traffic. The 4 groups were matched for age, gender, and blood pressure values, the 2 obese groups with and without obstructive sleep apnea showing a similar increase in body mass index (32.4 versus 32.0 kg/m2, respectively) and waist-to-hip ratio (0.96 versus 0.95, respectively) compared with the 2 lean groups with or without obstructive sleep apnea (body mass index 24.3 versus 23.8 kg/m2 and waist-to-hip ratio 0.77 versus 0.76, respectively; P<0.01). Compared with the nonobstructive sleep apnea lean group, muscle sympathetic nerve activity showed a similar increase in the obstructive sleep apnea lean group and in the nonobstructive sleep apnea obese group (60.4±2.3 and 59.3±2.0 versus 40.9±1.8 bs/100 hb, respectively; P<0.01), a further increase being detected in obstructive sleep apnea subjects (73.1±2.5 bursts/100 heart beats; P<0.01). Our data demonstrate that the sympathetic activation of obesity occurs independently in obstructive sleep apnea. They also show that this condition exerts sympathostimulating effects independent of body weight, and that the obstructive sleep apnea–dependent and –independent sympathostimulation contribute to the overall adrenergic activation of the obese state.

Short- and long-term neuroadrenergic effects of moderate dietary sodium restriction in essential hypertension.

Background—In essential hypertension, marked restrictions in dietary sodium intake cause in the short-term period an increase in muscle sympathetic nerve traffic (MSNA) and a baroreflex impairment. The present study was set out to assess on a long-term basis the neuroadrenergic and reflex effects of moderate sodium restriction. Methods and Results—In 11 untreated mild to moderate essential hypertensive patients (age 42.0±2.6 years, mean±SEM), we measured beat-to-beat blood pressure (Finapres), heart rate (ECG), and MSNA (microneurography) at rest and during stepwise intravenous infusions of phenylephrine and nitroprusside. Measurements were performed at regular sodium intake, after 1 and 8 weeks of low-sodium diet (80 mmol NaCl/d), and repeated again at regular sodium intake. After 1 week, urinary sodium excretion was markedly reduced. This was accompanied by a slight blood pressure reduction, no heart rate change, and a significant increase in plasma renin activity, aldosterone, and MSNA (+23.0±4.6%P <0.05). Whereas baroreflex heart-rate control was unchanged, baroreflex modulation of MSNA was reduced by 46.8±5.1% (P <0.01). At the end of the 8-week low-sodium diet, the neurohumoral and baroreflex responses were similar to the ones observed after 1 week of the dietary intervention. All changes disappeared when regular sodium diet was restored. Conclusions—Thus, a moderate dietary sodium restriction triggers a sympathetic activation and a baroreflex impairment. Maintenance of low-sodium diet for several weeks does not attenuate these adverse adrenergic and reflex effects.

Neurogenic Abnormalities in Masked Hypertension

Patients with hypertension exhibit an increased sympathetic activity. No information exists as to whether this is the case in normotensive individuals in whom there is an increased ambulatory blood pressure, a condition termed “masked” hypertension. We studied 18 middle-aged subjects with masked hypertension in whom we measured muscle sympathetic nerve traffic (peroneal nerve and microneurography) and beat-to-beat arterial blood pressure at rest and during baroreceptor deactivation and activation. Measurements also included anthropometric values and insulin sensitivity (homeostasis model assessment index). Data were compared with those of 20 normotensive subjects, 18 subjects with white-coat hypertension, and 20 patients with “in-office” and “out-of-office” hypertension. All of the individuals were pharmacologically untreated and age-matched with subjects with masked hypertension. Patients with in- and out-of-office and white-coat hypertension displayed resting sympathetic nerve activity values significantly greater than normotensive subjects (75.8±2.5 and 70.8±2.2 versus 45.5±2.0 bursts per 100 heartbeats respectively; P<0.01). This was the case also for masked hypertension (73.5±2.4 bursts per 100 heartbeats; P<0.01), the degree of the sympathetic activation being similar for magnitude to that seen in the other 2 hypertensive conditions. Compared with normotensive subjects, baroreflex-heart rate control was significantly attenuated in all of the hypertensive states, whereas baroreflex-sympathetic control was unaffected. Homeostasis model assessment index was increased in patients with in- and out-of-office and white-coat hypertension, with a further increase in masked hypertension and a direct relation with resting sympathetic nerve traffic (r=0.46; P<0.01). These data provide the first evidence that masked hypertension is characterized by a marked sympathetic overdrive. They further show that the neurogenic alterations are coupled with metabolic and baroreflex abnormalities.

Long-term risk of diabetes, hypertension and left ventricular hypertrophy associated with the metabolic syndrome in a general population.

Objectives Metabolic syndrome is accompanied by an increased risk of developing diabetes mellitus. Limited or no evidence exists on whether and to what extent metabolic syndrome increases the risk of developing office hypertension, daily-life hypertension and left ventricular hypertrophy. Methods In 1412 individuals representative of the population of Monza, plasma glucose, office, home and ambulatory blood pressure, and echocardiographic left ventricular mass index were measured between 1990 and 1992 and 10 years later. New onset diabetes mellitus, new onset office, home and ambulatory hypertension as well as new onset left ventricular hypertrophy were assessed in individuals with and without metabolic syndrome (Adult Treatment Panel criteria) at the first examination. Results New onset diabetes mellitus, hypertension and left ventricular hypertrophy were all much more frequent in individuals with metabolic syndrome than in those without. In patients with metabolic syndrome, the adjusted risk of new onset diabetes mellitus was five to six times greater (P < 0.001), that of new onset office, home or ambulatory hypertension 3.5, 2.9 and 3.2 times greater (P < 0.001), respectively, and that of new onset left ventricular hypertrophy 2.6 times greater (P < 0.001). The most important predictors of new onset diabetes mellitus, hypertension and left ventricular hypertrophy were the baseline blood glucose, blood pressure and left ventricular mass index, respectively, with an independent contribution, in each condition, from other metabolic syndrome components. The metabolic syndrome as such did not have an additional predictive value. Conclusion In the general population, metabolic syndrome is associated with a marked increase in the risk not only of new onset diabetes mellitus but also of new onset office and daily-life hypertension, and left ventricular hypertrophy. This may account for the increased rate of cardiovascular morbidity and mortality exhibited with this condition in long-term studies.

Efficacy and tolerability profile of nebivolol vs atenolol in mild-to-moderate essential hypertension: results of a double-blind randomized multicentre trial.

The objective of this 12‐week double‐blind randomized multicentre study was to compare the efficacy and tolerability of nebivolol, a recently developed beta‐blocking agent with vasodilating properties, to the classical beta‐blocker atenolol. After a placebo run‐in phase, 205 mild‐to‐moderate middle‐age essential hypertensives were randomized to either nebivolol 5u2005mg daily (nu2005=u2005105) or atenolol 100u2005mg daily (nu2005=u2005100) over a period of 12 weeks. The primary endpoint of the study was the change in sitting systolic and diastolic blood pressure (SBP and DBP respectively) from baseline to week 12 of treatment. The two drugs induced similar significant antihypertensive effects, the SBP and DBP reduction amounting to–18.2u2005±u200514.0 and–14.6u2005±u20057.9u2005mmHg (meanu2005±u2005SD) for atenolol and −19.1u2005±u200512.9 and −14.8u2005±u20057.1 for nebivolol (pu2005<u20050.01 for all). This was the case also for standing blood pressure. Sitting and standing heart rate values were significantly reduced by both drugs, the bradicardic response induced by nebivolol treatment being significantly less than atenolol. Distribution of responders and non‐ responders was similar for nebivolol and atenolol, while the former drug showed a better tolerability profile and a lower incidence of side‐effects. These data provide evidence, that, for the same antihypertensive effects, nebivolol shows a better tolerability profile than atenolol and a lower incidence of adverse effects.

Total Cardiovascular Risk, Blood Pressure Variability and Adrenergic Overdrive in Hypertension: Evidence, Mechanisms and Clinical Implications

In hypertensive patients the risk of developing cardiovascular events and complications depends not only on the magnitude of the blood pressure elevation, but also, and to a consistent extent, on the presence of associated cardiovascular risk factors, concomitant disease and target organ damage. Recent findings suggest that also sympathetic overdrive and alterations in blood pressure variability (which are detected in hypertension) may participate at the increased cardiovascular risk of the patients with high blood pressure. This review will discuss the evidence collected over the past few years on the relationships between sympathetic activation and blood pressure variability and their impact on cardiovascular risk profile.