Secondary arterial hypertension: improvements in diagnosis and management in the last 10 years.

The diagnosis and management of secondary hypertension has improved in the last decade as a result of the advances in the acknowledgment of some physiopathologic mechanisms and mainly by the development of new diagnostic methods. Furthermore, the treatment of some types of secondary hypertension may be solved by noninvasive techniques. Hypertension of renal and renovascular origin, coarctation of the aorta, primary hyperaldosteronism, and adrenal medullary tumors are analyzed. The main results of some relevant studies on diagnostic and treatment of those diseases are presented. Also, some experimental methods are mentioned, taking into account the possibility of clinical use in the near future.

Arterial wall structure and dynamics in type 2 diabetes mellitus methodological aspects and pathophysiological findings.

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.

Latin American guidelines on hypertension. Latin American Expert Group.

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.

Categorización del síndrome metabólico de acuerdo con las variables que lo constituyen y su relación con la insulino-resistencia / Consensus definition of the metabolic syndrome and diagnostic criteria for identification and its relationshipo with the insulin-resistance syndrome

In recent years, the cardiovascular prevention has found a new clinical tool: the metabolic syndrome (MS). Arised in the observation of associations between risk factors, it is recognized as the clinical manifestation of insulin resistance. In the course of time, it was demonstrated that the presence of MS possess a prognostic value to predict death, nonfatal acute myocardial infarction, vascular stroke and the development of diabetes... The relationshipo to insulin resistance and diagnostic criteria for identification of the metabolic syndrome are given in the article.

Determinación no invasiva de aterosclerosis subclínica y estratificación del riesgo cardiovascular / Non invasive assessment of subclinical atherosclerosis and stratification of cardiovascular risk

At present, cardiovascular diseases are the most frequent cause of morbidity and mortality in the world. Atherosclerosis has an important roll in the pathophysiology of cardiovascular diseases, mainly on the ischemic cardiopathy...The incorporation of ultrasonic screening for non invasive detection of subclinical atherosclerosis would allow the identification of a higher numbe of patients at high risk for coronary event and recommended for primary prevention

Aterosclerosis subclínica y estimación de riesgo coronario: comparación de tablas de riesgo / Subclinical atherosclerosis and coronary risk assessment: comparing risk tables

Para guiar el tratamiento preventivo se utilizan distintas tablas de estimación de riesgo coronario. Por otro lado, las alteraciones de la pared arterial son una manifestación de aterosclerosis subclínica y su detección mediante ecografía puede emplearse para predecir eventos coronarios. Objetivo: Comparar la prevalencia de aterosclerosis subclínica evaluada mediante ecografía carótidofemoral entre grupos de bajo riesgo definidos por diferentes tablas. Material y métodos: Se estudiaron 151 pacientes dislipidémicos con edad de 53 ± 12 años (rango: 20-82 años; 45 por ciento varones), índice de masa corporal: 26 ± 3 kg/m2, 42 por ciento hipertensos, 17 por ciento tabaquistas y3 por ciento diabéticos a los que se les realizaron ecografías carótido-femorales y que calificaron paraevaluación de riesgo. Se calculó el riesgo individual mediante diferentes tablas de estimación de riesgo y se incluyeron los individuos con riesgo coronario estimado menor del 10 por ciento a diez años. Se excluyeron del análisis los pacientes con riesgo moderado y alto. Se definió aterosclerosis subclínica a la presencia de placas ateroscleróticas en la ecografía arterial. Secomparó la prevalencia de aterosclerosis subclínica entre los grupos de bajo riesgo. Resultados: Uno de cada dos pacientes considerados de bajo riesgo presentó aterosclerosis subclínica, independientemente de la tabla utilizada. No hubo diferencias significativas en la prevalencia de aterosclerosis subclínica entre subgrupos. El 73 por ciento de los pacientes fueron categorizados de bajo riesgo por ATP III y el 78 por ciento por AHA/ACC, en comparación con el 45 por ciento calculado por Europea II (p < 0,001). Conclusiones: La ecografía carótido-femoral complementa la evaluación realizada mediante tablas de riesgo en la toma de decisiones terapéuticas en prevención primaria.

Combinación de un inhibidor de la enzima convertidora de la angiotensina con un antagonista del calcio versus la monoterapia con el IECA: eficacia terapéutica en hipertensión arterial esencial y regresión de la hipertrofia cardíaca / Combination of a converting enzyme inhibitor (ACEI) with a calcium antagonist versus monotherapy with an ACEI: therapeutic efficacy in essential hypertension and regression of ventricular hypertrophy

Objetivo: Evaluar la eficacia y la tolerancia, así como su acción sobre la regresión de la hipertrofia ventricular izquierda, de la combinación de benazepril más amlodipina (B + A) versus la monoterapia con benazepril (B). Material y métodos: Se incluyeron 33 hipertensos esenciales. Durante 6 meses de tratamiento, 18 de ellos recibieron B + A (9 varones, 55 ± 2 años) y los 15 restantes recibieron B (10 varones, 49 ± 2 años). Se realizó una presurometría (MAPA) al comienzo y a los 3 y a los 6 meses de tratamiento. En un subgrupo de 23 pacientes se calculó la masa ventricular izquierda (MVI) y el índice de MVI (IMVI) al inicio y al final del tratamiento. Resultados: A los 3 meses de tratamiento, los valores de la presión arterial (PA) fueron significativamente menores (p < 0,05) en los pacientes tratados con B + A que con B (24 horas: 123 ± 1,7 / 77 ± 1,8 versus 132 ± 1,5 / 85 ± 1,6 mm Hg; día: 127 ± 1,9 / 81 ± 1,8 versus 137 ± 1,8 / 91 ± 1,9 mm Hg; noche: 115 ± 2,0 / 68 ± 2,1 versus 122 ± 2,0 / 76 ± 1,7 mm Hg). Esto se logró con una dosis menor y hubo mejor tolerancia. En el grupo B + A, la MVI y el IMVI disminuyeron de 225,3 ± 47,4 g y 125,5 ± 19,3 g/m², a 187,2 ± 45,1 g y 104,7 ± 27,2 g/m2 (p < 0,05), mientras que en el grupo B la disminución no resultó estadísticamente significativa. Al finalizar el tratamiento, sólo en los pacientes tratados con B + A se observó una correlación positiva entre el descenso de la PAS y la MVI (r = 0,56, p < 0,025) y el IMVI (IMVI: r = 0,60; p < 0,01). Conclusión: La combinación B + A mostró una reducción de la PA más precoz. Se requirió una dosis menor y se obtuvo mejor tolerancia clínica que con B solo. En relación con la MVI y el IMVI, estos parámetros disminuyeron en forma significativa sólo en B + A.

Smart damping modulation of carotid wall energetics in human hypertension: effects of angiotensin-converting enzyme inhibition.

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.

Clasificación de la hipertensión arterial en base a la definición del JNC VII y las guías de las Sociedades Europeas de Hipertensión Arterial y Cardiología 2003 / Classification of arterial hypertension

Las normas para la clasificación clínica de la hipertensión arterial publicadas reciente y casi conjuntamente por el NIH americano (JNC VII) y las Sociedades Europeas de Hipertensión Arterial y Cardiología (SEH-C) coinciden en considerar como hipertensión arterial al promedio de dos o tres mediciones consecutivas iguales o superiores a 140/90 mmHg, en posición sentada. La presión normal es definida por el JNC VII como inferior a 120/80 mmHg, siendo considerados los valores intermedios como estadio prehipertensivo. La SEH-C extiende, como fue clásico en las normativas previas, el valor de normotensión hasta 134/84 mmHg, denominando presión arterial óptima a los valores menores de 120/80 mmHg y presión normal alta a los valores entre 135-139/85-89 mmHg. Las normativas europeas asocian a la clasificación cuantitativa la presencia o no de otros factores de riesgo cardiovascular y/o enfermedades cardíacas, definiendo riesgo bajo, intermedio, alto o muy alto cuando existen dichas asociaciones, destacando en particular la presencia de diabetes y la comorbilidad cardiovascular. Estas normativas diferencian también la hipertensión arterial sistólica aislada, de particular prevalencia en la población mayor de 65 años, y destacan el valor de la presión de pulso como factor de riesgo cardiovascular independiente. La investigación de las complicaciones orgánicas, así como la posibilidad de hipertensión secundaria, ha sido enfocado con mayor detalle en las normativas europeas.

Mención de espesor íntima-media arterial y detección precoz de aterosclerosis. Relación con factores de riesgo y eventos cardiovasculares / Measurement of artery intima-media thickness and early detection of atherosclerosis. Association with risk factors and cardiovascular events

La aterosclerosis es el proceso inicial de eventos cardiovasculares, constituyéndose en la causa más importante de morbimortalidad en la actualidad. Como la aterosclerosis es una enfermedad crónica que se desarrolla durante un período prolongado antes de expresarse clínicamente, se han desarrollado distintas técnicas para detectar y medir las alteraciones precoces de la aterosclerosis, entre ellas figura la medición del espesor íntima-media. El método ultrasónico empleado en esta medición es no invasivo, permitiendo el monitoreo de la evolución de cada paciente. La precisión de este estudio ha sido validada con mediciones en piezas de anatomía patológica. La medición del espesor íntima-media tiene una reproducibilidad aceptable para detección y progresión de enfermedad. El valor del espesor íntima-media aumentado se asocia a los principales factores de riesgo coronario y a un mayor riesgo de futuros eventos cardiovasculares. Su medición es utilizada como el estado aterosclerótico actual del paciente y como predictor de riesgo de manifestación clínica de enfermedad cardiovascular. El aumento del espesor íntima-media, indicador de enfermedad subclínica, podría reflejar no sólo la posibilidad de la ocurrencia de eventos, sino también las consecuencias de la exposición previa a factores de riesgo. Por lo tanto se ha propuesto utilizar la medición del espesor íntima-media como un marcador de aumento del riesgo cardiovascular en poblaciones con alta incidencia de enfermedad cardiovascular o factores de riesgo cardiovsculares. Consecuentemente sería útil en la identificación del subgrupo de pacientes con mayor riesgo cardiovascular de la población general, para iniciar estrategias agresivas de prevención primaria o secundaria.

Parallel renal and extremity blood supply abnormalities in nonmodulation: responses to ACE inhibition.

The aim of this work was to ascertain, in nonmodulating essential hypertension, whether the abnormality in the renal blood supply is extended to the extremities and showed a similar response to ACE inhibition and whether these abnormalities could be identified in normotensive offspring of hypertensives, as non-modulation is a familial process with genetic underpinnings. We measured forearm vascular blood flow (FBF) and forearm vascular resistance (FVR) by plethysmography and urinary albumin excretion in 20 normotensive without family story of hypertension (NT: 25+/-9 years), 10 modulating offspring of hypertensive parents (MHO: 25+/-6 years), 10 nonmodulating offspring of hypertensive parents (NMHO: 26+/-5 years), 12 modulating essential hypertensives (MHT: 34+/-5 years), and 11 nonmodulating essential hypertensives (NMHT: 32+/-4 years). Measurements were repeated in hypertensives after 3-month treatment with ramipril (5 mg daily). Nonmodulating individuals showed lower maximum FBF (NMHT: 41.96+/-3.3 mL/100 g per minute and NMHO: 35.6+/-9.0 mL/100 g per minute) than modulating subjects (MHT: 57.5+/-10.0 mL/100 g per minute and MHO: 51.8+/-7.0 mL/100 g per minute; P<0.003). Likewise, all nonmodulating subjects showed higher minimum FVR (NMHT: 2.5+/-0.2 AU; NMO: 2.8+/-0.5 AU) than modulating individuals (MHT: 1.9+/-0.5 AU; MHO, 1.8+/-0.3AU; P<0.025). Urinary albumin excretion was higher in NMHT and NMHO than MHT, MHO, and NT (P<0.05). Ramipril increased maximum FBF to 53.8+/-8.0 mL/100 g per minute and reduced minimum FVR to 1.9+/-0.5 AU in NMHT (P<0.01). Likewise, ramipril increased effective renal plasma flow and reduced renal vascular resistance and urinary albumin excretion only in NMHT (P<0.05). These results have shown an early involvement of the peripheral circulation in association with increased urinary albumin excretion not only in essential hypertensives but also in NMHO. The effectiveness of ramipril in reducing minimum FVR and urinary albumin excretion in NMHT also suggests a common mechanism.

Reduced activity of the kallikrein-kinin system predominates over renin-angiotensin system overactivity in all conditions of sodium balance in essential hypertensives and family-related hypertension.

OBJECTIVE: To study the renin-angiotensin-aldosterone and kallikrein-kinin systems in essential hypertensives and offspring of hypertensive parents during different sodium loads, and to explore their possible influence on renal hemodynamics. METHODS: Forty-five essential hypertensives (35 +/- 4 years old, 25 males), 30 offspring of hypertensive parents (26 +/- 8 years old, 16 males) and 30 normotensive controls (28 +/- 5 years old, 20 males) were submitted to three different sodium loads (high, 250 mmol/l; normal, 140 mmol/l; and low, 20 mmol/l). Blood pressure, plasma renin activity, serum aldosterone, total kallikrein and urinary kallikrein-like activity were measured after each period. Effective renal plasma flow and glomerular filtration rate were also measured. In essential hypertensive subjects, renal hemodynamic and hormonal parameters were also measured after 3 days of 20 mg enalapril administration. RESULTS: Plasma renin activity and serum aldosterone were higher in normotensives, essential hypertensives and offspring of hypertensive parents only during low sodium intake, whereas urinary kallikrein activity was lower in hypertensive offspring and essential hypertensives, compared with normotensives, during the three diet conditions. Effective renal plasma flow was found to be reduced in hypertensives and normotensive offspring, while the glomerular filtration rated was similar in the three groups. Angiotensin converting enzyme inhibitor (ACEI) administration to essential hypertensives for 3 days normalized effective renal plasma flow, increased plasma renin activity and decreased aldosterone and urinary kallikrein activity. CONCLUSIONS: Our observations confirmed the presence of a hormonal imbalance between the renin-angiotensin-aldosterone system and the kallikrein-kinin system, not only in essential hypertensives but also in the offspring of hypertensive parents. This imbalance probably affects the renal circulation and sodium homeostasis, since there was reduced effective renal plasma flow in both populations compared with normotensive subjects. The positive effect of ACEI, resulting in normalization of the effective renal plasma flow in essential hypertensive patients, suggests the involvement of both systems in impaired renal circulation.

Renal function and outcome of PTRA and stenting for atherosclerotic renal artery stenosis.

BACKGROUND: Prior studies of percutaneous transluminal renal artery angioplasty and stenting (PTRAS) for atherosclerotic renal artery stenosis (RAS) have shown that renal function is improved in about 25%, stabilizes in about 40%, but worsens in about 25% of patients. The factors predicting benefit remain controversial. We tested the hypothesis that the baseline glomerular filtration rate (GFR) predicts the changes in GFR and blood pressure (BP) after PTRAS. METHODS: Treated hypertensive patients with positive renal color-coded duplex Doppler velocimetry and clinical criteria were screened by arteriography. Patients (N = 105) were included if they had an RAS >or=70%, a transluminal pressure gradient >or=30 mm Hg and, they had more than 100 days of follow-up. GFR was calculated from the serum creatinine concentration (SCr). Patients were divided by baseline GFR into subgroups with normal to mildly impaired (N = 52) or moderately to severely impaired (N = 53) initial GFR, according to a GFR >or=50 or <50 mL. min-1 respectively. All received PTRAS. RESULTS: For the entire group, after a mean follow-up period of 371 days, there were significant reductions in systolic and diastolic BP (before, 160 +/- 26/91 +/- 12 vs. after, 145 +/- 20/83 +/- 10 mm Hg, respectively; mean +/- SD; P < 0.0001), and a modest increase in the calculated GFR (before, 54 +/- 26 vs. after, 62 +/- 28 mL. min-1; mean +/- SD; P < 0.007). However, in the subgroup of patients with an initially lower GFR there was a significant increase in the calculated GFR (from 33.3 +/- 10 to 54 +/- 24 mL. min-1; mean +/- SD; P < 0.0001) despite no significant change in BP (161 +/- 27/90 +/- 12 vs. 151 +/- 21/86 +/- 12; P = NS). In contrast, in the subgroup with an initially higher GFR, there were significant (P < 0.0001) reductions in systolic BP (from 159 +/- 25 to 138 +/- 16 mm Hg) and diastolic BP (from 91 +/- 11 to 81 +/- 9 mm Hg), but no significant change in the calculated GFR (from 75 +/- 21 to 70.2 +/- 30 mL. min-1; P = NS). The significance of GFR variation in subgroups remained after correction of baseline data to exclude the influence of the expected regression to the mean. CONCLUSIONS: 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).

Mechanical vs intrinsic components in the improvement of brachial arterial compliance: comparison of the effects of atenolol versus ramipril in hypertensive patients

The aim of this study was to compare the mechanical and intrinsic effects of an angiotensin converting enzyme inhibitor, vs a b-blocker, on brachial arterial compliance. In a double blind study, 34 essential hypertensive patients were treated for 3 months with either ramipril 2.5-5.0 mg daily (n=17, age 57 + or - 7y, 11 males) or atenolol 50-100 mg daily (n=17, age 53 + or - 8y, 11 males). Blood pressure (BP), brachial artery diameter (D), brachial-radial pulse wave velocity (PWV) and effective compliance (Ceff), were measured before and at the end of the study. Isobaric evaluation (Ciso) was performed in the entire population studied at an average mean BP of 110 mmHg. Ramipril significantly reduced BP from 155 + or - 16/94 + or - 6 mmHg to 140 + or - 15/85 + or - 7 mmHg (p<0.001) without affecting heart rate (HR; 74 + or - 10 vs. 75 + or - 12 bpm). In addition, it significantly improved both PWV (18 percent; p<0.001) and arterial compliance (45 percent; p<0.001), from which 35 percent was related to a pressure independent effect (p<0.01). Atenolol also induced a reduction in both BP (159 + or - 17/96 + or - 10 to 133 + or - 13/81 + or - 8 mmHg; p<0.001) and HR (76 + or - 10 to 57 + or - 7 bpm; p<0.001). In a similar way, PWV (11 per cent; p<0.05) and Ceff (30 per cent; p<0.05) were significantly improved without significant change in Ciso. This suggests that blood pressure reduction was responsible for compliance improvement. In conclusion, it is suggested that atenolol induces only hemodynamic changes, mediated mainly by BP reduction. In contrast, the improved brachial buffering function observed after ramipril involves not only hemodynamic changes, but also changes mediated by other mechanisms, such as modification of wall structures.

Evaluacion de las alteraciones circulatorias de la hipertension arterial mediante la determinacion no invasiva de la impedancia arterial / Vascular dysfunction in hypertension evaluated by noinvasive assessment of arterial impedance

Los efectos de la hipertensión sobre las arterias de conducción se han transformado en un motivo de considerable atención. Estos efectos pueden ser evaluados mediante tres componentes: resistencia periférica, compliance arterial y reflexión de la onda de pulso. El incremento de la resistencia periférica y de la rigidez arterial generan alteraciones en las condiciones de carga del ventrículo izquierdo y cambios morfológicos de las ondas de presión y flujo. Esto puede provocar a largo plazo cambios estructurales del ventrículo izquierdo, incremento del consumo de oxígeno y disminución de la perfusión coronaria. El análisis de la función arterial requería hasta hace un tiempo de mediciones invasivas. El objetivo de esta revisión es poner ter manifesto una metodología no invasiva, al alcance de un centro de diagnóstico, que posibilite determinar los parámetros constitutivos de la impedancia arterial para la evaluación de las alteraciones hemodinámicas inducidas por la hipertensión.

Estudio de la función arterial y diagnóstico precoz del deterioro vascular por hipertensión arterial / Analysis of arterial function in arterial hypertension

Recientemente se ha demostrado el efecto delétereo de la hipertensión sobre los parámetros que determinan la impedancia arterial. Estas anormalidades en la función arterial han sido detectadas tanto en hipertensos establecidos como en aquellos sin enfermedad cardiovascular aparente, por lo cual algunos autores sugieren que estas alteraciones pueden ser marcadores precoces del desarrollo de enfermedad arterial hipertensiva. El objetivo de este estudio fue determinar por métodos no invasivos las alteraciones de los parámetros que constituyen la impedancia arterial en los estados iniciales y en la hipertensión establecida

Evaluación de la actividad del sistema renina-angiotensina-aldosterona y de kalikreína urinaria ante diferentes sobrecargas de cloruro de sodio en hipertensión esencial / Evaluation of the renin-angiotensin system and kalikrein activity in essential hypertensives under differents sodium loads

OBJETIVOS: Evaluar el nivel de actividad renínica plasmática, aldosterona sérica y la actividad de kalikreína urinaria y la respuesta presora en hipertensos esenciales comparando los hallazgos con el de una población normotensa luego de la administración de diferentes regímenes de cloruro de sodio. MATERIAL Y METODO: En 30 normotensos, 20 varones y 10 mujeres de 31 ñ 5 años y 39 hipertensos esenciales, 20 varones y 19 mujeres de 35 ñ 7 año, se indicó en forma consecutiva a tres diferentes cargas de cloruro de sodio de 10 días cada una conteniendo 240, 140 y 50 mEq de Na+. Al finalizar cada período se registró la presión arterial sistólica, presión arterial diastólica y se obtuvieron muestras de sangre para la determinación del nivel de actividad renínica plasmática, aldosterona sérica y orina de 24 horas para la medición de kalikreína urinaria. RESULTADOS: Se comprobó únicamente con el contenido de 50 mEq Na+ niveles de actividad renínica plasmática (8,01 ñ 1 ng/ml/hora) y de aldosterona sérica (371 ñ 59 pg/ml) en hipertensos significativamente más elevados que en los sujetos normotensos (p< 0,01). La kalikreína urinaria fue hallada significativamente más reducida en los hipertensos respecto de los normotensos en las tres condiciones de ingreso salino: elevada (10,4 ñ 1,0; 7,62 ñ 0,5 UI), moderada (5,4 ñ 1,0; 12 ñ 1 UI) y reducida (10,4 ñ 1,0; 17 ñ 12,0 UI) (p< 0,01). La presión arterial se incrementó con la carga de sodio y descendió con la restricción únicamente en los hipertensos. CONCLUSIONES: La elevada actividad del sistema renina-angiotensina-aldosterona y la reducida actividad de kalikreína urinaria observada en la hipertensión esencial podrían hallarse vinculadas con alteraciones en el tono vascular renal que podrían influir en la normal regulación del sodio