Joaquín Montero L

Exceso de mineralocorticoides en hipertensos esenciales: enfoque clínico-diagnóstico

Background: Primary hyperaldosteronism is more frequent among subjects with essential hypertension than previously thought. The prevalence, according to local and international evidence could fluctuate between 9 and 10%. Aim: To investigate if subjects with essential hypertension have different aldosterone and renin plasma levels than normotensive subjects. Patients and methods: One hundred twenty five subjects with essential hypertension, not receiving medications for at least two weeks prior to the study and 168 age and sex matched normotensive controls were studied. Blood was drawn between 9 and 10 AM during a sodium free diet to determine plasma aldosterone, plasma renin activity and potassium. Results: Plasma aldosterone was higher in hypertensive subjects than controls (11.6 ± 7.6 and 9.9 ± 5.1 ng/dl respectively; p=0.04). Plasma renin activity was lower in hypertensives than controls (1.42 ± 1.28 and 1.88 ± 1.39 ng/ml/h respectively; p<0.001). Thus, plasma aldosterone/plasma renin activity ratio was higher in hypertensives (13.8 ± 13.5 and 8.3 ± 7.8; p<0.001). A pathological ratio was defined as over 25, corresponding to the mean plus two standard deviations of the control group. Primary hyperaldosteronism was found in 5/125 hypertensives (4%) and 1/168 normotensive subject (0.6%). None had hypokalemia. Conclusions: Subjects with essential hypertension have higher plasma aldosterone and lower plasma renin activity than normal controls. A plasma aldosterone/plasma renin activity over 25 was defined as abnormal. (Rev Med Chile 2000; 128: 955-61)

Tabaquismo en Atención Primaria: Perfil de fumadoras consultantes, creencias y actitudes de los equipos de salud y oportunidades de intervención

BACKGROUND Chile has one of the highest prevalence rate of smoking in the world. Brief counseling interventions for smoking cessation at the primary health care level are effective. Compliance with counseling intervention is strongly associated with beliefs and attitudes of the primary health care team that deliver it. The effectiveness of these interventions improve if they are applied to smoking populations with higher motivation of change and high self-efficacy for quitting. AIM To study the smoking profile of a group of smoking women in Santiago and to identify beliefs and attitudes of the primary health care team members to implement smoking cessation interventions. MATERIAL AND METHODS A cross-sectional design that included 306 women smokers attending two primary health care clinics in Santiago. Perceptions, beliefs and attitudes of 34 primary care team members from three clinics in Santiago were explored using a qualitative methodology. RESULTS The study identified a subgroup of 18% of women highly motivated to quit (decisional stage of change) and a 58% with a high self-efficacy. Beliefs and attitudes of staff at the clinics were characterized by invisibility, ambivalence and fatalism regarding the effectiveness of smoking cessation interventions. CONCLUSIONS There is a subgroup of smoking women with a high probability of quitting if they receive an appropriate counseling. Developing a systematic approach for smoking cessation intervention at the primary care setting in Chile should consider the invisibility, ambivalence and fatalism of primary health care team members towards this topic.

Alta prevalencia de enfermedad tiroidea subclínica en sujetos que concurren a control de salud

Background: There is no information about the prevalence of thyroidal diseases in the general Chilean population. Aim: To assess the prevalence of thyroidal diseases in individuals attended in occupational health examinations. Subjects and methods: Four hundred seventy two individuals were examined between 1998 and 1999. In all, serum levels of thyroid hormones, TSH and anti thyroidal antibodies (anti microsomal, anti thyroid peroxidase and anti thyroglobulin) were measured. Results: Forty four subjects were excluded from the study due to an incomplete medical record and 18 due to a personal history of thyroidal disease. Abnormal serum levels of thyroid hormones or TSH were detected in 28 subjects (6.8%). Four (1%) had hypothyroidism, 23 a subclinical hypothyroidism (5.6%) and one (0.2%) had hyperthyroidism. In 87 subjects (21.2%) at least one of the antibodies was positive. Positive anti thyroid antibodies were found in 14 of 28 subjects (50%) with abnormal thyroid hormone levels, compared with 73 of 382 subjects (19.1%) with normal thyroid hormone levels. Thyroid dysfunction was twice as frequent in women than in men. Conclusions: In this sample, a 6.8% prevalence of abnormal thyroid function tests was detected. (Rev Med Chile 2001; 129: 155-60).

Análisis crítico de un artículo: Atenolol, ¿primera elección en el tratamiento de la hipertensión?

Background: Atenolol is one of the most widely used beta blockers clinically, and has often been used as a reference drug in randomized controlled trials of hypertension. However, questions have been raised about atenolol as the best reference drug for comparisons with other antihypertensives. Thus, our aim was to systematically review the effect of atenolol on cardiovascular morbidity and mortality in hypertensive patients. Methods: Reports were identified through searches of The Cochrane Library, MEDLINE, relevant textbooks, and by personal communication with established researchers in hypertension. Randomized controlled trials that assessed the effect of atenolol on cardiovascular morbidity or mortality in patients with primary hypertension were included. Findings: We identified four studies that compared atenolol with placebo or no treatment, and five that compared atenolol with other antihypertensive drugs. Despite major differences in blood pressure lowering, there were no outcome differences between atenolol and placebo in the four studies, comprising 6,825 patients, who were followed up for a mean of 4.6 years on all-cause mortality (relative risk 1.01 [95% CI 0.89-1.15]), cardiovascular mortality (0.99[0.83-1.18]), or myocardial infarction (0.99 [0.83-1.19]). The risk of stroke, however, tended to be lower in the atenolol than in the placebo group (0.85 [0.72-1.01]). When atenolol was compared with other antihypertensives, there were no major differences in blood pressure lowering between the treatment arms. Our meta-analysis showed a significantly higher mortality (1.13[1.02-1.25]) with atenolol treatment than with other active treatment, in the five studies comprising 17,671 patients who were followed up for a mean of 4.6 years. Moreover, cardiovascular mortality also tended to be higher with atenolol treatment than with other antihypertensive treatment. Stroke was also more frequent with atenolol treatment. Interpretation: Our results cast doubts on atenolol as a suitable drug for hypertensive patients. Moreover, they challenge the use of atenolol as a reference drug in outcome trials in hypertension

Análisis crítico de un artículo:El estudio ALLHAT: Diuréticos tipo tiazidas serían el fármaco de elección para iniciar tratamiento en hipertensión arterial

Context: Antihypertensive therapy is well established to reduce hypertension related morbidity and mortality, but the optimal first step therapy is unknown. OBJECTIVE: To determine whether treatment with a calcium channel blocker or an angiotensin converting enzyme inhibitor lowers the incidence of coronary heart disease (CHD) or other cardiovascular disease (CVD) events vs treatment with a diuretic. DESIGN: The Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), a randomized, double blind, active controlled clinical trial conducted from February 1994 through March 2002. Setting and participants: A total of 33357 participants aged 55 years or older with hypertension and at least 1 other CHD risk factor from 623 North American centers. INTERVENTIONS: Participants were randomly assigned to receive chlorthalidone, 12.5 to 25 mg/d (n = 15255); amlodipine, 2.5 to 10 mg/d (n = 9048); or lisinopril, 10 to 40 mg/d (n = 9054) for planned follow up of approximately 4 to 8 years. Main outcome measures: The primary outcome was combined fatal CHD or nonfatal myocardial infarction, analyzed by intent to treat. Secondary outcomes were all cause mortality, stroke, combined CHD (primary outcome, coronary revascularization, or angina with hospitalization), and combined CVD (combined CHD, stroke, treated angina without hospitalization, heart failure [HF], and peripheral arterial disease). Results: Mean follow up was 4.9 years. The primary outcome occurred in 2956 participants, with no difference between treatments. Compared with chlorthalidone (6 years rate, 11.5%), the relative risks (RRs) were 0.98 (95% CI, 0.90-1.07) for amlodipine (6 years rate, 11.3%) and 0.99 (95% CI, 0.91-1.08) for lisinopril (6 years rate, 11.4%). Likewise, all cause mortality did not differ between groups. Five years systolic blood pressures were significantly higher in the amlodipine (0.8 mm Hg, P =.03) and lisinopril (2 mm Hg, P <.001) groups compared with chlorthalidone, and 5 years diastolic blood pressure was significantly lower with amlodipine (0.8 mm Hg, P <.001). For amlodipine vs chlorthalidone, secondary outcomes were similar except for a higher 6 years rate of HF with amlodipine (10.2% vs 7.7%; RR, 1.38; 95% CI, 1.25-1.52). For lisinopril vs chlorthalidone, lisinopril had higher 6 years rates of combined CVD (33.3% vs 30.9%; RR, 1.10; 95% CI, 1.05-1.16); stroke (6.3% vs 5.6%; RR, 1.15; 95% CI, 1.02-1.30); and HF (8.7% vs 7.7%; RR, 1.19; 95% CI, 1.07-1.31). Conclusion: Thiazide type diuretics are superior in preventing 1 or more major forms of CVD and are less expensive. They should be preferred for first step antihypertensive therapy

Mecanismos de hipo e hiper alfalipoproteinemia en individuos adultos chilenos

Background: High density lipoprotein (HDL) cholesterol is inversely associated to atherosclerotic cardiovascular risk. Disturbances in HDL cholesterol plasma leves are frecuent in the Chilean population, however the pathophysiological mechanisms are unknown. Aim: To evaluate the mechanisms involved in the hypo and hyper alfalipoproteinemias in Chilean subjects. Materials and Methods: Twenty three subjects with hyperalphalipoproteinemia and 12 with hypoalphalipoproteinemia, paired with control subjects (colHDL between 35 and 55 mg/dl) were studied. We measured plasma lipids, subfractions and sizing of HDL particles and enzymatic activity of cholesteryl ester transfer protein (CETP), lecithin: cholesterol acyltransferase (LCAT), lipoprotein lipase (LPL) and hepatic lipase (LH). Results: Subjects with hyperalphalipoproteinemia showed significantly higher levels of total HDL-cholesterol (70±2 vs 44±1 mg/dl), HDL 2 (30±3 vs 5±1 mg/dl), Apo A I (175±3 vs 146±4 mg/dl), lower HL activity (23,7±0,8 vs 32,4±1,8 mmol/h/l) and HDL particles of greater size, compared to their controls. Subjects with hypoalphalipoproteinemia, showed significantly lower levels of total HDL-cholesterol (26±1 vs 48±2 mg/dl), HDL 3 (21±1 vs 40±2 mg/dl), Apo A I (107±5 vs 145±7 mg/dl), lower LCAT activity (18,6±1,9 vs 26,2±1,6 nmol/h/ml) and smaller HDL particles, compared to their controls. Conclusion: Changes in hepatic lipase and lecithin cholesterol acyltransferase activities may explain the hyper and hypo alphalipoproteinemia respectively, in Chilean subjects (Rev Med Chile 2004; 132: 421-8). (Key Words: Lecithin acyltransferasa deficiency; Lipoproteins, HDL; Lipoproteins, HDL cholesterol; Lipoproteins, VLDL cholesterol)

Actividad de 11 beta hidroxiesteroide dehidrogenasa tipo 2 en hipertensos chilenos

Background: Half of hypertensive patients with low plasma renin activity have a primary hyperaldosteronism. Among the remaining half, 11s-hydroxysteroid dehydrogenase type 2 (11sHSD2) deficiency plays an important role. This enzyme catalyzes the conversion of cortisol to cortisone, avoiding the interaction of cortisol with the mineralocorticoid receptor. If the enzyme fails, cortisol will stimulate sodium and water reabsorption and increase blood pressure. Aim: To determine biochemical alterations, suggestive of 11sHSD2 deficiency, in low-renin hypertensive patients. Patients and Methods: Twenty eight hypertensive patients with a plasma renin activity of less than 0.5 ng/ml/h and with a plasma aldosterone of less than 5 ng/dl were studied. Twenty eight normotensive patients were studied as controls. Serum cortisol (RIA), cortisone (ELISA) and the serum cortisol/cortisone ratio were determined in all of them, between 9 and 10 AM. Measurements were confirmed by high pressure liquid chromatography. The serum cortisol/cortisone ratio was considered abnormal when its Ln (cortisol/cortisone) value was over 2 standard deviations of the mean. Results: Serum cortisol was higher in hypertensive subjects than in controls (11.1±3.3 and 9.2±2.8 µg/dl, respectively; p <0.05). No differences were observed in serum cortisone (3.4±1.3 and 3.7±1.2 µg/dl, respectively). Four hypertensive subjects had an abnormally high Ln (cortisol/cortisone) value (1.86; 1.73; 2.07 and 2.01, considering a normal value of less than 1.61). Conclusions: Four of 28 hypertensive subjects with low plasma renin activity and aldosterone had biochemical alterations suggestive of 11sHSD2 deficiency (Rev Med Chile 2002; 130: 1201-8).