ISSN:0194-911X    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The treatment of hypertension with high-dose thiazide diuretics results in potassium depletion and a limited benefit for preventing coronary events. The clinical relevance of hypokalemia associated with low-dose diuretics has not been assessed. To determine whether hypokalemia that occurs with low-dose diuretics is associated with a reduced benefit on cardiovascular events, we analyzed data of 4126 participants in the Systolic Hypertension in the Elderly Program (SHEP), a 5-year randomized, placebo-controlled clinical trial of chlorthalidone-based treatment of isolated systolic hypertension in older persons. After 1 year of treatment, 7.2% of the participants randomized to active treatment had a serum potassium <3.5 mmol/L compared with 1% of the participants randomized to placebo (P<0.001). During the 4 years after the first annual visit, 451 participants experienced a cardiovascular event, 215 experienced a coronary event, 177 experienced stroke, and 323 died. After adjustment for known risk factors and study drug dose, the participants who received active treatment and who experienced hypokalemia had a similar risk of cardiovascular events, coronary events, and stroke as those randomized to placebo. Within the active treatment group, the risk of these events was 51%, 55%, and 72% lower, respectively, among those who had normal serum potassium levels compared with those who experienced hypokalemia (P<0.05). The participants who had hypokalemia after 1 year of treatment with a low-dose diuretic did not experience the reduction in cardiovascular events achieved among those who did not have hypokalemia.

ISSN:0194-911X    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Blood pressure measured by the oscillometric, automated device DINAMAP in 3 large population-based studies sponsored by the National Heart, Lung, and Blood Institute (The Atherosclerosis Risk in Communities Study, The Family Heart Study, and the Hypertension Genetic Epidemiology Network Study) were reviewed to determine an apparent skip pattern in the measurement values. Across the 3 studies, 2 different DINAMAP models were evaluated on >350 000 different blood pressure measurements. Measurements were taken in various positions, on both arm and ankles, and under various conditions (eg, resting and during stress). The following systolic blood pressure values were consistently skipped by the device: 89, 119, 120, 124, 125, 130, 140, 141, 150, 160, 170, 180, 190, and 200 mm Hg. No skip pattern was detected for diastolic blood pressure. Pulse data, which were only available in the Hypertension Genetic Epidemiology Network Study, also showed the following skipped values: 95, 99, 103, 106, and 109 bpm. Consultation with the manufacturer, the Critikon Corporation, indicated that the use of an algorithm designed to improve the accuracy of the DINAMAP device prevents these values from being displayed. Assessment of the extent and direction of bias caused by the skipped values is difficult, given that the algorithm is proprietary. While the implications of the skipped values are not clear, it is important for clinicians and researchers to be aware of this feature.

ISSN:0194-911X    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The aim of our investigation was to determine whether the presence of additional risk factors or type of hypertension (diastolic or isolated systolic) influences blood pressure (BP) response to treatment. The International Nifedipine GITS Study: Intervention as a Goal in Hypertension Treatment (INSIGHT) study is a double-blinded outcome comparison of calcium channel blockade with diuretics in high-risk patients aged 55 to 80 years. Dynamic randomization between nifedipine once daily and hydrochlorothiazide/amiloride was performed to ensure that approximately equal numbers of patients in the 2 groups had each of the major cardiovascular risk factors. Patients with isolated systolic hypertension were also separately randomized. Atenolol or enalapril was the mandatory second-line drug. In 5669 patients who completed the 18-week titration, BP fell from 172±15/99±9 mm Hg (mean±SD) while receiving placebo to 139±12/82±7 mm Hg. Twenty-six percent of patients required 2 drugs, and 4% required 3 drugs. Patients with diabetes were the most resistant to treatment, requiring second and third drugs 40% and 100% more frequently than patients without diabetes and achieving marginally the highest final BP, for any risk group, of 141±13/82±8 mm Hg. Age, smoking, gender, hypercholesterolemia, left ventricular hypertrophy, and existing atherosclerosis had little (<1 mm Hg) or no influence on BP at the end of titration, but all except smoking slightly reduced the initial response of either systolic or diastolic BP. Patients with isolated systolic hypertension were slightly more responsive than average to treatment. Our findings suggest that in patients at high absolute risk of cardiovascular complications from hypertension, the risk factors themselves do not prevent the recommended BP targets from being achieved.

ISSN:0194-911X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Normal insulin action in vivo involves a decrease in stiffness of large arteries (a decrease in aortic pressure augmentation). We determined whether the ability of insulin to decrease arterial stiffness is altered in uncomplicated type 1 diabetes. Nine type 1 diabetic men (age 28±2 years, body mass index 24±1 kg/m2) and 9 matched normal men were studied under normoglycemic hyperinsulinemic (sequential 2-hour insulin infusions of 1 [step 1] and 2 [step 2] mU · kg−1· min−1) conditions. Central aortic pressure waveforms were synthesized from those recorded in periphery with applanation tonometry on the radial artery and a validated reverse transfer function to construct the central aortic pressure wave every 30 minutes. This allowed the determination of aortic augmentation (the pressure difference between the first and the second systolic peaks) and the augmentation index (augmentation divided by pulse pressure), as the measure of stiffness of large arteries. Whole-body glucose uptake was 44% (step 1) and 37% (step 2) lower (P<0.001) in the diabetic patients than in the normal subjects. At baseline, before the insulin infusion, augmentation averaged 0±1 and 2±1 mm Hg (NS) and the augmentation index was −1.5±4.5% and 4.0±3.7% (NS) in the normal and diabetic subjects, respectively. After 1 hour of hyperinsulinemia, the augmentation index had decreased significantly (P<0.01) to −9.5±4.8% in the normal subjects but remained at 4.4±4.2% in the diabetic patients. A significant decrease was not observed in the diabetic patients until 150 minutes (−1.2±4.1%,P<0.05 versus baseline). Whole-body glucose uptake was significantly inversely correlated with the change in the augmentation index during step 1 (r=−0.61,P<0.01). Insulin resistance in type 1 diabetes involves a defect in the ability of insulin to decrease central aortic pressure. This defect could predispose these patients to premature stiffening of large arteries.

ISSN:0194-911X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

We have previously shown that the decrease in large artery distensibility observed in patients with essential hypertension (HT group) was primarily due to an increase in distending pressure and not to hypertension-associated structural modifications of the artery, suggesting a functional adaptation of the wall material. To evaluate the elastic properties of the wall material of the common carotid artery, we determined Young’s incremental elastic modulus (Einc) in the HT group and in normotensive subjects (NT group) as a function of blood pressure and circumferential wall stress. In 102 HT patients with never-treated essential hypertension and 40 age- and gender-matched NT subjects, the Einc-pressure and Einc-stress curves were calculated from intima-media thickness and from diameter and pressure waveforms, determined with echo tracking and aplanation tonometry, respectively. The “effective” stiffness of the wall material, determined through Einc calculated at mean blood pressure, was significantly higher in the HT than in the NT group. The “intrinsic” stiffness of the wall material, determined through Einc calculated at a common circumferential wall stress, did not differ between the 2 groups. However, when each group (HT and NT) was analyzed according to tertiles of age, the “intrinsic” stiffness of the arterial wall material was increased only in younger HT patients. In middle-aged and older HT patients, the intrinsic mechanical properties of the carotid arterial wall material were unchanged, and the increased stiffness of the common carotid artery in the HT group was due primarily to the increased level of blood pressure. These results also indicate that the deleterious effects of aging and hypertension on “intrinsic” stiffness are not additive.

ISSN:0194-911X    

出版商:OVID    

年代:2000

数据来源: OVID