A. Leth

Changes in plasma volume and extracellular fluid volume after addition of prazosin to propranolol treatment in patients with hypertension.

In fifteen patients with hypertension, inadequately controlled during treatment with propranolol alone (mean dosage 333 mg/day), plasma volume (PV) and extracellular fluid volume (ECV) were determined. After addition of prazosin for 3 months (mean dosage 9 mg/day) there was a significant increase in PV and ECV, on average 8 and 5%, respectively. The decrease in supine blood pressure, systolic as well as diastolic, was very modest, on average 11 mmHg (SD +/- 12) and 4 mmHg (SD +/- 7), respectively. The changes in standing blood pressure were more pronounced. It is assumed that the expansion of PV and ECV contributes to the inadequate blood pressure response found in the present study.

Plasma noradrenaline concentration in hypertensive and normotensive forty-year-old individuals: Relationship to plasma renin concentration

Forty-year-old individuals with labile and with mild sustained essential hypertension, identified during a survey of a population born in 1936, were investigated. None had ever received antihypertensive treatment. In thirty-three individuals (26 M, 7F) with diastolic blood pressure (DBP) greater than or equal to 95 mmHg at the very first examination and in thirty-one (14 M, 17 F) randomly selected normotensive controls plasma noradrenaline concentration (PNAC) was measured at rest supine. In twenty-two patients (16 M, 6 F), with sustained diastolic hypertension (diastolic blood pressure greater than or equal to 95 mmHg on at least three different occasions) and in twenty-four (14 M, 10 F) normotensive controls PNAC and plasma renin concentration (PRC) were measured supine at rest and again 2 h after furosemide and ambulation. Basal and acutely stimulated values for PNAC and PRC were identical in hypertensive and normotensive individuals. A close correlation between PNAC and PRC after acute stimulation (r = 0.77, P < 0.001) as well as between the absolute changes from resting to acutely stimulated values (r = 0.72, P < 0.001) were found in the hypertensive individuals. It is concluded that sympathetic nerve activity, as defined from measurements of plasma noradrenaline concentration, is similar in young patients with mild hypertension and in normotensive controls. We propose that the discrepancies found in the literature might be related to a lack of comparability between hypertensive and normotensive individuals studied, as far as the source of study populations is concerned.

The renin-angiotensin system during converting enzyme inhibition with captopril in patients with severe treatment-resistant hypertension.

Abstract. The effect of captopril on blood pressure (BP) and various components of the renin‐angiotensin system was assessed in ten severely hypertensive patients. Captopril acutely reduced the BP with a maximum decrease of 23% at 90–120 min.

Angiotensin II blockade during combined thiazide-β-blocker treatment

Sixteen patients (11 M, 5 F), median age 41 years, with essential hypertension insufficiently controlled on hydrochlorothiazide 75 mg/day (DBP≥100 mmHg) were investigated. Plasma renin concentration (PRC), angiotensin II concentration (PA II), aldosterone concentration (PAC), plasma noradrenaline concentration (PNAC), plasma volume (PV) and exchangeable sodium (NaE) were determined and a saralasin-infusion (5·4 nmol/kg/min) was carried out while the patients were on thiazide alone, and in fourteen cases, repeated 3 months later after addition of a β-blocker (propranolol 6, metoprolol 6 and atenolol 2 patients). On thiazide alone PRC, PA II and PAC was higher than normal in the group as a whole and the angiotensin II-inhibitor, saralasin, caused a significant decrease in MAP in twelve out of sixteen patients. After addition of a β-blocker SBP and DBP decreased from 164/109 mmHg to 136/94 mmHg. PRC and PA II decreased by 40% and 58%, respectively. At this point saralasin caused no significant change in MAP....