Damping is the conversion of mechanical energy of a structure into thermal energy, and it is related to the material viscous behavior. To evaluate the role of damping in the common carotid artery (CCA) wall in human hypertension and the possible improvement of angiotensin-converting enzyme (ACE) inhibition, we used noninvasive CCA pressure (tonometry) and diameter (B-mode echography) waveforms in normotensive subjects (NT group; n=12) and in hypertensive patients (HT group; n=22) single-blind randomized into HT-placebo (n=10) or HT-treated (ramipril, 5 to 10 mg/d during 3 months; n=12). Vascular smooth muscle (VSM) null tonus condition was achieved from in vitro pressure and diameter waveforms (Konigsberg microtransducer and sonomicrometry) measured in explanted human CCA (n=14). Arterial wall dynamics was described by viscous (eta), inertial (M), and compliance (C) parameters, mean circumferential wall stress, viscous energy dissipation (WD), peak strain energy (WSt), damping ratio (xi=WD/WSt), and modeling isobaric indexes CIso and WSt(Iso). The lack of VSM tonus isobarically increased wall stress and reduced eta, CIso, and damping (P<0.01). Wall stress, eta, and WD were greater in HT than in NT (P<0.015) and arrived near normal in HT-treated (P<0.032 respect to HT), with no changes in HT-placebo. Whereas CIso increased in HT-treated (P<0.01) approaching the NT level, xi did not vary among groups. During hypertension, because of the WSt increase, the arterial wall reacts increasing WD to maintain xi. ACE inhibition modulates VSM activation and vessel wall remodeling, significantly improving wall energetics and wall stress. This protective vascular action reduces extra load to the heart and maintains enhanced arterial wall damping.

Hypertension is a highly prevalent cardiovascular risk factor in the world and particularly overwhelming in low and middle-income countries. Recent reports from the WHO and the World Bank highlight the importance of chronic diseases such as hypertension as an obstacle to the achievement of good health status. It must be added that for most low and middle-income countries, deficient strategies of primary healthcare are the major obstacles for blood pressure control. Furthermore, the epidemiology of hypertension and related diseases, healthcare resources and priorities, the socioeconomic status of the population vary considerably in different countries and in different regions of individual countries. Considering the low rates of blood pressure control achieved in Latin America and the benefits that can be expected from an improved control, it was decided to invite specialists from different Latin American countries to analyze the regional situation and to provide a consensus document on detection, evaluation and treatment of hypertension that may prove to be cost-utility adequate. The recommendations here included are the result of preparatory documents by invited experts and a subsequent very active debate by different discussion panels, held during a 2-day sessions in Asuncion, Paraguay, in May 2008. Finally, in order to improve clinical practice, the publication of the guidelines should be followed by implementation of effective interventions capable of overcoming barriers (cognitive, behavioral and affective) preventing attitude changes in both physicians and patients.

Abstract-Increases m arterial wall vlscoslty and mtlma-media thickness (IMT) were found m hypertensive patients Because smooth muscle cells are responsible for the viscous behavior of the artenal wall and they are involved m the process of thickening of the mtlma-media complex, this study evaluates the relationship between carotid thickness and wall vlscos~ty The simultaneous and nomnvaslve assessment of the mtlma-media complex and arterial diameter waveform was performed using high-resolution ultrasonography This technique was contrasted agamst sonomlcrometry m sheep, showmg that the waveforms obtained by both methods were surular The common carotid arteries of 11 normotenslve subjects (NTA) ayd 11 patients with rmld to moderate essential hypertension (HTA) were measured nomnvaslvely by usmg tonometry and Ian automatic densltometrlc analysis of B-mode Images to obtam IMT and instantaneous pressure and diameter loops A vlscoelastlc model was used to derive the wall vlscoslty mdex (7) using the hysteresis loop ehmmatlon criteria In NTA, 7 was 2 7321 66 (mm Hg * s/mm) and IMT was 0 58+0 08 ( mm , whereas m HTA, q was 5 91?2 34 (K 025) and ) IMT was 0 7020 12 (P< 025), respectively When all data of q versus IMT of NTA and HTA were pooled m a linear regression analysis, a correlation coefficient of r= 71 (P< 05) was obtained Partial correlation between q and IMT holding constant pressure was r= 59 (PC 05) In conclusion, wall vlscoslty increase was associated with a higher IMT even mamtammg blood pressure fixed, suggestmg that the mtlma-media thickening might be related to smooth muscle alterations manifested as an Increase m viscous behavior (H~~eutension.1998;31[part 2]:534-539.)Key Words: wall thickness n arterial wall vlscoslty n hypertension H tonometry A complete charactenzatlon of geometric, elastic, and VIS-COUS propertles of arteries has been proposed on the basis of mvaslve recordings of pressure and diameter pulses, allowing the determination of the pressure-diameter hysteresis loop m conscious chronically instrumented dogs ' Moreover, another study provided a complete m vlvo descnptlon of geometric, elastic, and viscous properties of carotid and femoral artenes m human hypertension' m which recent nonmvaslve vascular techniques, applanatlon tonometry, and Doppler postprocessmg M-mode images were applied for measurmg pressure and diameter pulses Wall v~scoslty was estimated as the area of the diameter-pressure hysteresis loop dunng the procedure of loop ehmmatlon Compared to normotenslve subJects, hypertensive patients had an increased wall vlscoslty index m the carotid artery This increased wall vlscoslty might be the consequence of hypertensive vascular hypertrophy and particularly of the partlclpatlon of the smooth muscle m that hypertrophy Moreover, the smooth muscle component among the arterial wall constituents has been demonstrated to be responsible for the viscous behavior of the diameter-pressure relatlonshlp',3 An increased wall thickness m carotid arteries of asymptomatlc hypertensive patients h...

Patients with atherosclerotic RAS fulfilling strict criteria of severity may have significant improvements in BP one year after PTRAS but only modest in GFR. The initial GFR may anticipate whether the benefits in the outcome will be in renal function enhancement (those with an initially depressed GFR) or in hypertension control (those with an initially normal or mildly impaired GFR).

Type 2 Diabetes Mellitus (DM), or adult-onset diabetes, is being considered as a new pandemic. Cardiovascular disease is the major cause of morbidity and mortality in type 2 DM, due to arterial structure and functional changes. Assessment of arterial structure and biomechanics, by non-invasive methods and parameters, can be used to detect early alterations related to DM. Three markers of vascular disease may help to a better evaluation of vascular dysfunction in type 2 DM patients: carotid intimamedia thickness (IMTc), arterial stiffness, assessed by pulse wave velocity (PWV), and endothelial function, evaluated through the brachial artery flow-mediated dilation (FMD). Among these parameters, IMTc is considered a marker of structural vessel wall properties, and arterial stiffness reflects functional wall properties. Endothelial function represents the arterial way to actively regulate its diameter (smooth muscle-dependent actions) and its visco-elastic properties (wall elasticity and viscosity). IMTc is increased in patients with type 2 DM and other independent risk factors, such as: age, hyperlipidemia and duration of DM. Subjects with DM have shown increased arterial stiffness. Type 2 DM is associated with reductions in FMD (endothelial dysfunction), which has already been reported to be inversely and strongly related to the extent of hyperglycemia. The underlying patho-physiological mechanisms are complex and remain to be fully elucidated. A complete understanding of the association between arterial alterations and early detection, and type 2 DM, may be critical for the primary prevention of DM-related macro-vascular disease.

Exercise might reduce blood pressure in mild essential hypertensive individuals, but it could raise left ventricular mass, counteracting the beneficial effects induced by a decrease in blood pressure. Seventeen (group 1) of 25 mild hypertensive patients, nonresponders to a 3-month low sodium diet (2 g/day), were admitted into a physical training program consisting of three weekly sessions of aerobics (20 minutes), bicycling at prefixed loads (20 minutes), and induced muscular relaxation (10 minutes). They were compared with 15 mild hypertensive patients (group 2), nonresponders to the low sodium diet who remained untrained. The follow-up lasted 15.7±5.8 months. There were significant blood pressure decreases in group 1 at rest (155 ±9. P hysical training has been used for the treatment of mild hypertensive patients with diverse results. Many authors 1 -2 have pointed out significant decreases in systolic and diastolic blood pressure (BP), whereas others have failed to demonstrate such beneficial effects. 3 We were able to get significant decreases in systolic and diastolic BP measured at rest and during exercise in a group of mild essential hypertensive patients who followed a physical training program (PTP) for at least 12 months. 4 It is known that trained people, mainly athletes, have cardiac enlargement. Endurance athletes develop cardiac dilation 5 -6 and hypertrophy, whereas "resistive" athletes such as lifters or throwers develop an inappropriate increase in left ventricular wall thickness. -8 This is not the case with hypertensive patients who followed a PTP From the Cardiology and Kinesiology Divisions, Policlinica Bancaria, Buenos Aires, Argentina.Address for correspondence: Hugo P. Baglivo, MD, Gaona 2197 (1416), Buenos Aires, Argentina. because the intensity of exercise is graded according to the individual physical capacity and BP levels; however, it is still possible that physical training can induce an increase in left ventricular mass (LVM), which could counteract the beneficial clinical effects produced by a BP decrease. This study was designed to investigate the effects of a moderate and prolonged PTP on LVM.Methods Twenty-five white mild essential hypertensive patients were placed on a low sodium diet (2 g/day) for 3 months; 17 of them had a persistent diastolic BP greater than 90 mm Hg. These patients (group 1), 12 men and five women, with a mean age of 50.8±7.9 years, were admitted into a PTP. They were compared with 15 untrained white mild essential hypertensive patients (group 2), 10 men and five women, with a mean age of 49.3±3.2 years, who were nonresponders to the same low sodium diet and who did not undergo any other treatment. All patients were subjected to routine examinations by guest on May 9, 2018 http://hyper.ahajournals.org/ Downloaded from

The metabolic syndrome is a complex association of several risk factors including insulin resistance, dyslipidemia, and essential hypertension. Insulin resistance has been associated with sympathetic activation and endothelial dysfunction, which are the main mechanisms involved in the pathophysiology of hypertension and its related cardiovascular risk. According to the Sixth Report of the Joint National Committee, and guidelines of the World Health Organization/International Society of Hypertension, the presence of multiple risk markers suggests that both hypertension and risk factors should be aggressively managed in order to obtain a better outcome. Primary prevention of obesity at different levels--individual, familial, and social-- starting early in childhood has proven to be cost effective, and will be mandatory to reduce the world epidemic of obesity and its severe consequences.

Wall inertia increase was associated with a higher IMT, suggesting that the intima-media thickening might be partially related to vascular hypertrophy manifested as increase of inertial behaviour.