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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasma and urinary catecholamines (norepinephrine and epinephrine) and urinary dopamine excretion were studied in 45 essential hypertensive patients subdivided into borderline (labile) and stable hypertension. Borderline hypertensive patients had a higher mean fractional renal clearance of catecholamines (the clearance of catecholamines relative to creatinine clearance) than both control subjects and stable hypertensive patients. A significantly positive correlation between the renal clearance of catecholamines and urinary dopamine excretion was also found in those with borderline hypertension, but not in control subjects or those with stable hypertension. These data indicate that patients with borderline hypertension have a relatively exaggerated renal catecholamine release. They probably reflect an increased sympathetic discharge to the kidney in "borderline" hypertension, occuring to a lesser degree in stable hypertension and control subjects. Thus, urinary catecholamine measurements do not specifically reflect the level of circulating catecholamines, particularly in borderline hypertension.
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PMID:An increase in urinary catecholamines of renal origin in patients with "borderline" hypertension. 101 11

Suppression of renin release by beta-adrenoceptor blocking drugs has been advocated as the prime blood pressure lowering mechanism of these agents. The present report casts doubt on this proposition in three ways. In the first study, involving 22 patients with borderline hypertension, patients with elevated plasma renin levels showed normalization of the blood pressure after pharmacological autonomic blockade with intravenous atropine, propranolol and phentolamine, the time course of the pressure fall being such as to exclude suppression of renin release as the antihypertensive mechanism. It is clear that in patients with mild hypertension and high plasma renin levels, the elevation of blood pressure is maintained by a neurogenic mechanism, the elevated plasma renin having no direct role in sustaining the higher blood pressure. In two additional studies involving 21 patients in all with mild to moderately severe essential hypertension, to whom propranolol was administereed by mouth for 1--3 months, two findings were of interest:1) patients with low-renin essential hypertension showed a good antihypertensive response to propranolol, and 2) in some patients a dosedependent dissociation of the renin and blood pressure lowering action of propranolol could be demonstrated. These findings militate against the assumption that propranolol selectively lowers the blood pressure in "renin-dependent" hypertension, and strongly suggest that the antihypertensive action of this drug is not mediated by depression of plasma renin activity.
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PMID:Dissociation of the renin lowering and antihypertensive actions of propranolol. 103 70

1. In 20 of 20 patients (100%) with borderline hypertension Visken normalized the labile blood pressure. The high renin values after stimulation due to orthostasis and saluresis decreased significantly (p less than 0,01). 2. In 3 of 12 patients (25%) with hyporeninemic essential hypertension Visken alone normalized the blood pressure. The low renin values increased to the normal range. 3. In 4 of 18 patients (22%) with normoreninemic essential hypertension Visken normalized the blood pressure. The normal renin values showed a decreasing tendency within the normal range. 4. In 4 of 10 patients (40%) with hyperreninemic essential hypertension Visken normalized the high blood pressure. In 3 of these patients renin decreased distinctly. 5. In 4 of 20 patients (20%) with renal hypertension a therapy with Visken alone normalized the blood pressure. In 3 patients the high renin values decreased to the normal range. 6. In the most other patients of the groups II to V the additional therapy with diuretics and reserpine normalized the blood pressure. In these cases the renin values showed different reactions corresponding to the different effects of betablocking agents, saluretics or reserpine on the plasma renin activity [7]. 7. It is interesting, that Visken not only suppresses high renin values (borderline hypertension [6], hyperreninemic essential hypertension), but also increases low renin values to the normal range in patients with hyporeninemic essential hypertension. Because in essential hypertension the high blood pressure per se may be responsible for the renin suppression [3,4], this increase of renin activity is possibly the consequence of blood pressure reduction, while the decrease of renin activity after Visken may be the cause of blood pressure reduction.
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PMID:[Effect of pindolol (Visken) on blood pressure and plasma renin activity in various forms of hypertension]. 103 71

Systolic time intervals were measured in 54 hypertensive patients divided into three groups according to severity of hypertension, variability of blood pressure levels and presence or absence of a hyperkinetic heart. The three groups were: borderline hypertension (BLH), fixed essential hypertension (FEH) and hyperkinetic essential hypertension (HEH). Systolic time intervals (STI) provided information indicating an increased cardioadrenergic drive in BLH and HEH. This was supported by finding that propranolol abolished the increased contractility found at rest in BLH and HEH.
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PMID:Use of systolic time intervals in studying hypertension. 106 29

1. A first sample of a cross-section of the Belgian population was studied. 2. The presence of hypertension or borderline hypertension was established on the basis of two examinations at 1-3 weeks intervals, during which the blood pressure was measured four times after 10 min rest. 3. The prevalence of both hypertension and borderline hypertension increased with age in the two sexes and, independently of age, with the relative weight. 4. The probable effect of arm circumference in overestimation of blood pressure in heavy subjects was analysed by multivariate correlations. It was concluded that if the influence of arm circumference is excluded, the effect of relative weight on blood pressure is less marked but still present.
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PMID:Effect of weight on prevalence of hypertension, and its interaction with the arm circumference: Belgian Hypertension Committee Epidemiological Study. 107 4

Medical data from Selective Service registrants born from 1939 to 1941 were studied in Oregon and Colorado. Among 29,119 registrants with medical information (41.3% of all registrants), 1,073 (3.6%) had definite hypertension, and 1,226 (4.2%) had some type of color blindness. In both states, there was a highly significant association between the prevalence of hypertension and the prevalence of color blindness. Thus, definite hypertension was present in 6.0% of color clind individuals but in only 3.6% of those with unimparied color vision, while color blindness occurred in 6.8% with definite hypertension, in 5.8% with borderline hypertension, and in only 4.0% with normal blood pressure. The data did not differentiate among types of color blindness, and the reason for the association is not yet evident.
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PMID:Hypertension and color blindness in young men. 108 40

The sensitivity of the baroreceptor reflex in nine patients with borderline hypertension (mean age 19.1 plus or minus 0.2 years) was compared to that in six normal subjects of comparable age (mean 18.8 plus or minus 0.3 years) and that in 14 patients with established hypertension (mean age 48.3 plus or minus 3.1 years). The sensitivity of the baroreceptor reflex was assessed by determining the slope of the regression line relating the rise of systolic pressure to the prolongation of the R-R Interval during the transient rise of arterial pressure induced by an intravenous injection of phenylephrine. The average baroreceptor slope in nine patients with borderline hypertension was 9.1 plus or minus 0.8 msec/mm Hg, which was significantly less than that in six normal subjects (16.0 plus or minus 2.0; P smaller than 0.01), but was greater than that in 14 patients with established hypertension (4.9 plus or minus 0.7; P smaller than 0.01). The significant negative correlation was found as the baroreceptor slope was related to the mean arterial pressure in patients with borderline hypertension and normal subjects, all of whom were 20 years old or less. Attenuation of the baroreceptor sensitivity may influence the maintenance of raised arterial pressure in borderline hypertension.
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PMID:Reduced baroreceptor sensitivity in borderline hypertension. 111 60

Hemodynamic changes in supine and upright position and during exercise were studied in 144 men including 37 normal subjects and 107 patients with borderline hypertension. Borderline hypertensives were classified in 4 groups, according to the basal level of heart rate and stroke index. In the first two groups, stroke index was normal, but heart rate was either decreased (Group I) or elevated (Group II): supine total peripheral resistance was superior (Group I; p less than 0.02) or equal (Group II) to normal values; plasma volume was normal or slightly decreased; hemodynamic response to tilt test closely approximated the normal; impaired adaptation of cardiac index and stroke index to exercise was observed in Group II (p less than 0.001). In the other two groups, stroke index was significantly elevated (p less than 0.0001) but heart rate was either decreased (Group III) or increased (Group IV); supine total peripheral resistance values were decreased (p less than 0.001); plasma volume was equally reduced (p less than 0.001); abnormal percentile increase in diastolic arterial pressure (p less than 0.02; p less than 0.001) and total peripheral resistance during tilt test were observed; during exercise, only the patients of Group IV had an impaired adaptation of cardiac index (p less than 0.001) and total peripheral resistance (p less than 0.02). The study provide evidence that in boderline hypertension i) a high basal level of stroke volume is associated with a reduced plasma volume and an imparied adaptation of total peripheral resistance during tilt, ii) a high basal level of heart rate is associated with an impaired adapatation of cardiac output during exercise, and iii) only patients having an increase in both heart rate and stroke volume exhibited a specific hemodynamic pattern including: reduction of plasma volume, impaired adaptation of cardiac output during exercise, impaired adaptation of total peripheral resistance during tilt and exercise.
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PMID:The stroke volume in juvenile borderline hypertension. 112 Oct 55

During the first 5 years of a community-based referral hypertension clinic, 331 ambulatory patients referred for diagnostic evaluation. Thirty-four patients were judged to be normotensive on the basis of resting blood pressures on 3 separate days. In 51 patients the diagnosis was borderline hypertension and 220, essential hypertension. Twenty-six patients (10.6%) had secondary hypertension. Twenty-one patients with secondary hypertension were first recognized from the data of the history, physical examination, and routine urinalysis. The main cost per patient of the initial and further evaluations was computed for each group of patients. The average cost to identify one case of secondary hypertension in the clinic was $2083. Because of the large problem with hypertension in the United States today, the cost-effectiveness of various approaches to the evaluation of patients with hypertension requires thoughtful reappraisal.
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PMID:Cost and yield of the hypertensive evaluation. Experience of a community-based referral clinic. 113 86

The relation of renin-angiotensin status to general hemodynamics and to neurogenic vascular resistance was studied in patients with border-line hypertension. Plasma renin activity during standing was referred to a standard renin-urinary sodium nomogram derived from 18 normal subjects. Among 22 patients with borderline hypertension the renin level was high in 8, low in 4 and within normal limits in the remaining 10. In patients with borderline hypertension and high or normal levels of plasma renin activity, the blood pressure elevation was due to increased total peripheral vascular resistance. In contrast, in patients with low renin borderline hypertension, total peripheral resistance was not significantly elevated; the blood pressure elevation reflected a cardiac index 12 percent higher than that in normal subjects. The neurogenic contribution to total peripheral vascular resistance was assessed by studying the effects of alpha adrenergic blockade with phentolamine, after prior autonomic blockade of the heart with atropine (0.04 mg/kg body weight) and propranolol (0.2 mg/kg). Phentolamine (15 mg) produced an immediate reduction in total peripheral resistance of 12.0 +/- 6.7 percent in patients with high renin borderline hypertension (P less than 0.01) but no change in normal subjects or those with borderline hypertension and normal or low renin levels. Normalization of the blood pressure followed "total" autonomic blockade with atropine, propranolol or phentolamine only in patients with high renin borderline hypertension. It is concluded from these preliminary data that in high renin borderline hypertension the blood pressure elevation is sustained by neurogenic mechanisms. The elevated renin level in these patients is probably an expression of increased sympathetic nervous activity. Although the elevated plasma renin level may possibly be contributing to the generation of higher sympathetic tone, or data do not support a direct role of circulating angiotensin in the maintenance of the elevated vascular resistance.
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PMID:Relation of renin status to neurogenic vascular resistance in borderline hypertension. 119 91


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