The new concept of total cardiovascular risk management

Introduction: Cardiovascular risk factors, such as hypertension, hypercholesterolemia, and diabetes mellitus, often cluster together and can also be seen with other pathophysiological conditions that greatly increase an individual's risk for cardiovascular morbidity and death. Aim of the study: This article emphasizes the importance of assessing and managing the total cardiovascular risk in an individual patient. Materials and methods: Suggestions and recommendations from the most current hypertension management guidelines have been integrated with results from the major clinical trials published in the last decade. Results: Based on a review of the epidemiological data on cardiovascular disease, this paper expands the concept of stratification of hypertensive patients according to the approximate added risk of major cardiovascular events in the next 10 years and stresses the importance of subclinical target-organ damage. Conclusions: Although common in clinical practice, high-risk patients are often undiagnosed. Intensive hypertensive therapy is recommended for high-risk patients, and this treatment strategy will require combination therapy to control or reverse subclinical organ damage and prevent the progression of cardiovascular risk in subjects at low risk or medium risk

Sympathetic activation and reflex abnormalities in the metabolic syndrome

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Effects of Chronic Clonidine Administration on Sympathetic Nerve Traffic and Baroreflex Function in Heart Failure

Abstract— Congestive heart failure is characterized by a sympathetic activation that is coupled with a baroreflex impairment. Whether these alterations are affected by clonidine is unknown. In 26 normotensive patients age 58.0±1.1 years (mean±SEM) affected by congestive heart failure (New York Heart Association functional class II or III) and treated with furosemide and enalapril, we measured mean arterial pressure, heart rate, venous plasma norepinephrine, and muscle sympathetic nerve traffic (microneurography) at rest and during baroreceptor stimulation and deactivation caused by stepwise intravenous infusions of phenylephrine and nitroprusside, respectively. Measurements were repeated after a 2-month administration of transdermal clonidine patch (14 patients) or placebo (12 patients) according to a double-blind, randomized sequence. Clonidine caused a slight, nonsignificant reduction in mean arterial pressure and heart rate without affecting exercise capacity and echocardiographically determined left ventricular ejection fraction. In contrast, both plasma norepinephrine and sympathetic nerve traffic were significantly reduced (−46.8% and −26.7%, respectively; P <0.01 for both). This reduction was coupled with no change in cardiac and sympathetic baroreflex responses. Transdermal placebo administration for a 2-month period did not affect any of the above-mentioned variables. Thus, in congestive heart failure patients who are undergoing conventional drug treatment, chronic clonidine administration exerts marked sympathoinhibitory effects without adversely affecting cardiac functions and clinical state. Whether this leads to further therapeutic benefits remains to be tested

Effects of long-term lercanidipine or hydrochlorothiazide administration on hypertension-related vascular structural changes.

Vascular remodelling and hypertrophy represent early therapeutic targets of antihypertensive treatment. The present study was aimed at assessing the effects of 1-year administration of the highly vasoselective calcium-channel blocker lercanidipine (10 mg/day) or the diuretic compound hydrochlorothiazide (25 mg/day) on hypertension-related vascular alterations. The study was also aimed at assessing whether and to what extent: (i) pharmacological regression of vascular hypertrophy is related only to the blood pressure (BP) reduction "per se" or also to the specific ancillary properties of a given drug and (ii) treatment provides restoration of vascular function indicative of normal vascular structure.In 26 untreated patients with mild-to-moderate essential hypertension sphygmomanometric and finger BP, heart rate, forearm and calf blood flow (venous occlusion plethysmography) and corresponding vascular resistance (forearm and calf vascular resistance: FVR and CVR) were assessed before and following 6 and 12 months of either lercanidipine or hydrochlorothiazide administration. Vascular resistance was also evaluated following a local ischaemic stimulus (FVR(min) and CVR(min)) in order to assess the effects of treatment on arteriolar structural alterations.For superimposable BP reductions, lercanidipine caused FVR and CVR to decrease significantly more than hydrochlorothiazide. Similarly, the FVR(min) and CVR(min) reductions induced by lercanidipine were markedly and significantly greater than those caused by hydrochlorothiazide (-46.1% and -40.9% vs -22.5% and -19.9%, p0.01 for both). FVR(min), and CVR(min), however, remained higher than those found in 10 age-matched normotensive individuals.These data provide evidence that, compared to hydrochlorothiazide, lercanidipine favours a greater regression of the vascular structural changes associated with hypertension, probably through its "ancillary" properties. Lercanidipine, however, does not allow restoration of a "normal" vascular structure, thereby suggesting that vascular hypertrophy is only in part a reversible phenomenon

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

Sympathetic Control of Circulation in Hypertension and Congestive Heart Failure

Adrenergic overactivity is a common hallmark of both essential hypertension and congestive heart failure. Indirect and direct measures of sympathetic function have clearly shown that sympathetic activation characterizes essential hypertension. This adrenergic overactivity appears to be related to the severity of the hypertensive state, being detectable in its early stages and showing a progressive increase with the severity of the disease. Essential hypertension is also associated with an impaired baroreflex control of vagal activity, whereas baroreceptor modulation of sympathetic nerve traffic remains unaltered, although undergoing a resetting phenomenon. In contrast, secondary hypertension is not associated with an increased adrenergic activity, thus suggesting that an enhancement in efferent sympathetic outflow is a peculiar feature of essential hypertension. Congestive heart failure is a condition also characterized by sympathetic activation, whose degree is proportional to the clinical severity of the disease. This is paralleled by an impairment in arterial baroreceptor modulation of both vagal and sympathetic activity, thus suggesting that the adrenergic overactivity in congestive heart failure is triggered by a reduced afferent restraint on the vasomotor centre. Chronic angiotensin-converting enzyme inhibition reduces the degree of both sympathetic activation and baroreflex dysfunction occurring in heart failure patients, a finding which documents that the neurohumoral abnormalities can be at least partially reversed by pharmacologic treatment

Photoplethysmography for Quantitative Assessment of Sympathetic Nerve Activity (SNA) During Cold Stress

The differences in the degree of sympathetic nerve activity (SNA) over cutaneous blood vessels, although known to be more prominent in the periphery than the core vasculature, has not been thoroughly investigated quantitatively. Hence, two studies were carried out to investigate the differences in SNA between the periphery and the core during the cold pressor test (CPT) (right-hand immersion in ice water) and cold exposure (whole body exposed to cold air) using photoplethysmography (PPG). Two methods utilizing PPG, namely differential multi-site PTT measurements and low-frequency spectral analysis were explored for quantitative determination of SNA. Each study involved 12 healthy volunteers, and PPG signals were acquired from the right index finger (RIF), left index finger (LIF) (periphery) and the ear canal (core). During CPT, Pulse Transit Time (PTT) was measured to the respective locations and the mean percentage change in PTT during ice immersion at each location was used as an indicator for the extent of SNA. During cold exposure, the low-frequency spectral analysis was performed on the acquired raw PPGs to extract the power of the sympathetic [low-frequency (LF): 0.04–0.15 Hz] and parasympathetic components [high-frequency (HF): 0.15–0.4 Hz]. The ratio of LF/HF components was then used to quantify the differences in the influence of SNA on the peripheral and core circulation. PTT measured from the EC, and the LIF has dropped by 5 and 7%, respectively during ice immersion. The RIF PTT, on the other hand, has dropped significantly (P < 0.05) by 12%. During the cold exposure, the LF/HF power ratio at the finger has increased to 86.4 during the cold exposure from 19.2 at the baseline (statistically significant P = 0.002). While the ear canal LF/HF ratio has decreased to 1.38 during the cold exposure from 1.62 at baseline (P = 0.781). From these observations, it is evident that differential PTT measurements or low-frequency analysis can be used to quantify SNA. The results also demonstrate the effectiveness of the central auto-regulation during both short and long-term stress stimulus as compared to the periphery

Adrenergic and reflex abnormalities in obesity-related hypertension

Previous studies have shown that essential hypertension and obesity are both characterized by sympathetic activation coupled with a baroreflex impairment. The present study was aimed at determining the effects of the concomitant presence of the 2 above-mentioned conditions on sympathetic activity as well as on baroreflex cardiovascular control. In 14 normotensive lean subjects (aged 33. 5+/-2.2 years, body mass index 22.8+/-0.7 kg/m(2) [mean+/-SEM]), 16 normotensive obese subjects (body mass index 37.2+/-1.3 kg/m(2)), 13 lean hypertensive subjects (body mass index 24.0+/-0.8 kg/m(2)), and 16 obese hypertensive subjects (body mass index 37.5+/-1.3 kg/m(2)), all age-matched, we measured beat-to-beat arterial blood pressure (by Finapres device), heart rate (HR, by ECG), and postganglionic muscle sympathetic nerve activity (MSNA, by microneurography) at rest and during baroreceptor stimulation and deactivation induced by stepwise intravenous infusions of phenylephrine and nitroprusside, respectively. Blood pressure values were higher in lean hypertensive and obese hypertensive subjects than in normotensive lean and obese subjects. MSNA was significantly (P:&lt;0.01) greater in obese normotensive subjects (49.1+/-3.0 bursts per 100 heart beats) and in lean hypertensive subjects (44.5+/-3.3 bursts per 100 heart beats) than in lean normotensive control subjects (32.2+/-2.5 bursts per 100 heart beats); a further increase was detectable in individuals with the concomitant presence of obesity and hypertension (62.1+/-3. 4 bursts per 100 heart beats). Furthermore, whereas in lean hypertensive subjects, only baroreflex control of HR was impaired, in obese normotensive subjects, both HR and MSNA baroreflex changes were attenuated, with a further attenuation being observed in obese hypertensive patients. Thus, the association between obesity and hypertension triggers a sympathetic activation and an impairment in baroreflex cardiovascular control that are greater in magnitude than those found in either of the above-mentioned abnormal conditions alone

Incidencia de fechas de supresión del cultivo de cobertura previo a maíz

La vicia villosa (VV) pura o consociada con una gramínea es una alternativa válida a ser utilizada como cultivo de cobertura (CC) previo al cultivo de maíz. Los aportes del CC y su influencia sobre el cultivo de cosecha va a depender del manejo como de las condiciones climáticas que ocurran durante el ciclo de ambos. La definición de la fecha de supresión del crecimiento del CC, en función de los pronósticos climáticos del ciclo agrícola, surge como una alternativa de manejo para tratar de lograr el mejor resultado posible del cultivo de cosecha. El objetivo de este trabajo fue evaluar el aporte de materia seca (MS), el porcentaje de humedad superficial, la cantidad de agua útil hasta 1,5 m de profundidad, la disponibilidad de nitrógeno (N) y el rendimiento del maíz en función de diferentes fechas de supresión del crecimiento del cultivo de VV y VV consociada con trigo (VV+T). Durante el ciclo 2021-22 se instalaron dos ensayos en lotes de producción de la EEA INTA Marcos Juárez, uno con VV y otro con VV+T como CC en los que se definieron cuatro fechas de supresión del crecimiento de los mismos previo a la siembra del maíz. La consociación VV+T aportó mayor cantidad de MS que la VV pura. El T afectó el crecimiento de la VV en la consociación. La disponibilidad superficial de N y el porcentaje de humedad superficial fueron afectados por los CC. El agua útil en el perfil del suelo previo a la siembra fue mayor sobre barbecho que sobre CC. No se observaron mayores beneficios al adelantar la fecha de supresión del crecimiento del CC para las variables medidas antes de la siembra, pero sí sobre el rendimiento del maíz.Estación Experimental Agropecuaria Marcos JuárezFil: Gudelj, Vicente Jorge. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; ArgentinaFil: Conde, María Belén. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; ArgentinaFil: Lorenzón, Claudio Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; ArgentinaFil: Marelli, Patricio Martín. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; ArgentinaFil: Seravalle, Rubén Darío. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; ArgentinaFil: Pereyra, Luciano Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; ArgentinaFil: Gudelj, Olga Esther. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; Argentin