Curable hypertension with unilateral hydronephrosis. Studies on the role of circulating renin

Among eight patients with unilateral hydronephrosis and hypertension, peripheral plasma renin activity was normal in seven and borderline high in one. Four patients had hydronephrotic/contralateral kidney renin ratios of greater than 1.5, suggesting excessive renin release from the diseased kidney, and ratios between contralateral kidney and peripheral blood of less than 1.2, indicating suppressed renin production in the contralateral kidney. Nephrectomy normalized blood pressure in each of these patients. Two patients had hydronephrotic/contralateral kidney renin ratios of less than or equal to 1.3 or contralateral kidney/periphery ratios of greater than 1.2, suggesting ischemia of the contralateral kidney; pyeloplasty or nephrectomy, or both, failed to improve the hypertension. Postoperative changes in blood pressure correlated with changes in peripheral renin (r = 0.90; P less than 0.01). These data suggest that hypertension associated with unilateral hydronephrosis is partly renin-dependent; and renal vein renin values are helpful in selecting patients for surgery.

Interrelations among blood pressure, blood volume, plasma renin activity and urinary catecholamines in benign essential hypertension

Interrelations among blood pressure, circulatory volume, plasma renin activity (PRA) and urinary catecholamine excretion rates were studied in normal subjects and in patients with benign essential hypertension. Mean plasma or blood volumes related to lean body mass, products of blood volume and the logarithm of PRA, and catecholamine excretion rates did not differ significantly between normal and hypertensive subjects. In both normal subjects and hypertensive patients, blood pressure levels correlated positively with the noradrenaline excretion rate (r = 0.40 and 0.36, respectively; p less than 0.025) but not with adrenaline excretion, circulatory volume or the volume-renin product. The logarithm of PRA correlated inversely with mean blood pressure in normal subjects (r = 0.40; p less than 0.001) but not in hypertensive patients; however, there was no convincing evidence for an inappropriate blood pressure-PRA relationship as a prominent feature in the hypertensive patients. PRA did not correlate with blood volume. Patients with low PRA relative to sodium excretion (21 per cent of hypertensive population) were consistently normovolemic, but they tended to be older and excreted less (p less than 0.025) adrenaline than patients with normal or high PRA. The patient subgroup with high PRA relative to sodium excretion (11 per cent of population) was hypovolemic (p less than 0.02); despite this, urinary sodium output was high (172 +/- 64 meq/24 hours). These data reveal no evidence for major roles of PRA, circulatory volume and free peripheral catecholamines in the maintenance of benign essential hypertension. Essential hypertension with low PRA is usually not a hypervolemic state, but it may reflect diminished adrenergic activity, factors associated with aging and effects of a high systemic pressure. High PRA in benign essential hypertension may be at least partly a consequence of hypovolemia resulting from high blood pressure-induced sodium diuresis.

[Correlations between blood pressure, blood volume and plasma renin during therapy with diuretics in essential hypertension. Comparison between the mineralocorticoid antagonist spironolactone and the "loop" diuretic mefruside]

35 patients with benign essential hypertension were treated for 6 weeks with high doses of the mineralocorticoid-antagonist spironolactone (400 mg/day), or with the "loop-diuretic" mefruside (mean maximal dose 110 mg/day). Spironolactone caused greater reductions in blood pressure and blood volume and a more marked increase in plasma renin activity (PRA) than mefruside (p less than 0.05). It appears possible that he weaker antihypertensive effect of mefruside may relate partly to its lesser influence on circulatory volume. With both diuretics, mean decreases in blood pressure were greater in patients with low pre-therapeutic PRA than in patients with normal or high PRA. However, the diuretic-induced changes in blood pressure did not correlate with the associated variations in blood volume or PRA. Thus, the increased blood pressure sensitivity to diuretics in patients with low-renin essential hypertension did not appear to be volume or renin-dependent. Under normal conditions, the maintenance of a constant blood pressure during volume depletion may partly depend on compensatory activation of the sympathetic nervous system. Moreover, patients with low-renin essential hypertension have been found to have decreased adrenergic activity. It seems possible, therefore, that the marked blood pressure sensitivity to diuretic treatment in such patients may be the result of an impaired compensatory sympathetic response to sodium and volume depletion. Analysis of the literature suggests that the diuretic furosemide, a structural relative of mefruside, may also have less blood pressure lowering efficacy in patients with essential hypertension than the distally-acting thiazides, chlorthalidone or spironolactone. Consideration of possible differences in the blood pressure reducing potential of certain diuretics thus appears to be necessary in planning the pharmacotherapy of essential hypertension.

[Correlations between blood pressure, blood volume, plasma renin and urinary catecholamines in normal subjects and in patients with benign essential hypertension]

Interrelations between blood pressure, circulatory volume, plasma renin activity (PRA) and urinary catecholamine excretion rates were studied in normal subjects and patients with benign essential hypertension. Mean plasma or blood volumes related to lean body mass, products of blood volume and the logarithm of PRA, and catecholamine excretion rates did not differ significantly as between normal and hypertensive subjects. In both normal subjects and hypertensive patients, blood pressure correlated positively with noradrenaline excretion rate (r = 0.40 and 0.36 respectively; p less than 0.025), but not with adrenaline excretion, circulatory volume or the volume-renin product. The logarithm of PRA correlated inversely with mean blood pressure in normal subjects (r = -0.40; p less than 0.001), but not in hypertensive patients; however, there was no convincing evidence of an inappropriate blood pressure-PRA relationship as a prominent feature in the hypertensive patients. PRA did not correlate with blood volume. Patients with low PRA relative to sodium excretion (21% of hypertensive population) were consistently normovolemic, but tended to be older and excreted less (p less than 0.025) adrenaline than normal or high-PRA patients. The patient subgroup with high PRA relative to sodium excretion (11% of population) was hypovolemic (p less than 0.02); despite this, urinary sodium output was high (172 +/- 64 meq/24 hr). These data reveal no evidence for major roles of PRA, circulatory volume and free peripheral catecholamines in the maintenance of benign essential hypertension. Low-PRA essential hypertension is usually not a hypervolemic state, but may reflect diminished adrenergic activity, factors associated with aging and effects of a high systemic pressure. High PRA in benign essential hypertension may be at least partly a consequence of hypovolemia resulting from high blood pressure-induced sodium diuresis.

[Interrelations between blood pressure, blood volume, plasma renin and urinary catecholamines during beta-blockade in essential hypertension (author's transl)]

Studies in 55 patients with benign essential hypertension showed that the beta-blockers bufuralol (22 patients) and propranolol (33 patients) at a dose ratio of 1:4, possess comparable antihypertensive efficacy despite different properties regarding intrinsic sympathomimetic activity. Beta-blocker-monotherapy normalized blood pressure ( less than 140/90 mm Hg) in one fourth of the patients. Body weight and plasma and blood volumes remained unchanged during beta-blockade of four to six weeks duration, the mean plasma potassium was slightly increased. The inhibition of plasma renin activity (PRA) was more pronounced with propranolol (-69%) than with bufuralol (-47%). Wirth both beta-blockers decreases in blood pressure correlated inversely with pre-treatment PRA (p less than 0.05). Propranolol-induced changes in blood pressure correlated also with associated changes in PRA (p less than 0.005); in contrast, no such relationship was observed with bufuralol. The blood pressure effects of bufuralol, however, correlated significantly with changes in urinary noradrenaline excretion (r=0.41; p less than 0.05). Patient sub-groups with low, normal or high pre-treatment PRA in the average showed a comparable pattern of pre-treatment noradrenaline excretion and patients with normal renin levels exreted more adrenaline than those with low renin levels (p less than 0.001). These data are consistent with the concept that in untreated essential hypertension PRA may be an index of adrenergic activiity, the latter representing an important determinant of blood pressure response to beta-blockade. The blood pressure lowering effects of bufuralol in benign essential hypertension seem to be independent of renin and may be related, at least partly, to diminished free peripheral noradrenaline levels.

Control of aldosterone responsiveness in terminal renal failure

Control of aldosterone responsiveness in terminal renal failure. Plasma aldosterone concentration in 30 hemodialysis patients correlated closely with renin concentration, renin activity or renin and potassium concentrations combined (r is greater than or equal to 0.62; P is less than 0.01), and increased consistently in response to upright posture or corticotropin administration. Aldosterone response to hemodialysis was variable. Significant correlations (r is greater than or equal to 0.65; P is less than 0.01) were demonstrated between postural plasma aldosterone and renin responses, between aldosterone responses to corticotropin and basal plasma aldosterone or renin and potassium values, between hemodialysis-induced changes in plasma aldosterone and those in potassium or renin; but not between various indexes of heparin treatment and aldosterone activity. Bilateral nephrectomy reduced basal plasma renin and aldosterone concentrations and aldosterone responsiveness in five preoperatively normoreninemic or hyperreninemic patients, but not in a hyporeninemic patient. These results demonstrate the complementary roles of circulating renin and potassium in the control of aldosterone release under basal and stimulatory conditions in patients with terminal renal failure. Administration of heparin in dosages used during long-term hemodialysis does not appear to significantly interfere with aldosterone control.

A critical appraisal of some aspects of outpatient care

The literature describing the development of community psychiatry is briefly reviewed with special emphasis on the application of its ideas to the lower socio-economic group.

Characteristics of lower class patients are described with some specific problems inherent in their outpatient care. A home visiting program is briefly described.

Situational factors and personal characteristics of lower class patients are considered to be more important in affecting therapy unfavourably than are biases in the therapist and communication problems.