Bernard Waeber

Ambulatory blood pressure recordings. Reproducibility and unpredictability.

The accuracy of blood pressure readings taken by the portable semiautomatic blood pressure recorder Remler M 2000 was investigated in 101 unselected, untreated volunteers. On the average, pressures recorded during usual daily activities were lower by approximately 10 mm Hg than pressures measured in the office. However, individual ambulatory pressures could not be predicted from office readings, and the difference varied among the volunteers from +14 to -43 mm Hg. The reproducibility of office and ambulatory pressures was investigated in 84 subjects. There was a highly significant correlation between pressure levels determined at a 3- to 4-month interval with both the conventional auscultatory method in the office and the Remler ambulatory recorder. These data demonstrate that the Remler M 2000 ambulatory blood pressure recorder, when used properly, provides reproducible blood pressure profiles during customary daily activities. The ambulatory pressure recorder seems particularly useful for a baseline evaluation of the usual daily blood pressure, which in the individual subject differs in a highly unpredictable manner from the blood pressure measured at the physicians office.

Ambulatory blood pressure recording to identify hypertensive patients who truly need therapy

Ambulatory blood pressure profiles were obtained with the Remler system, a portable semi-automatic blood pressure recorder, in 245 untreated patients considered by their physician to be hypertensive. The average blood pressures recorded during the usual daily activities of the patients were greater than 140 mmHg for the systolic and greater than 89 mmHg for the diastolic in only 96 (39%) and 107 (44%) of them respectively. Blood pressure monitoring in ambulatory patients appears to be useful for the practitioner to detect those patients who require antihypertensive therapy. Possibly, unnecessary therapy of only seemingly hypertensive patients may be avoided by this technique.

Renin and Angiotensin II Receptor Gene Expression in Kidneys of Renal Hypertensive Rats

The aim of this investigation was to examine the interrelation between renal mRNA levels of renin and angiotensin II receptor type 1 (AT1) in a renin-dependent form of experimental hypertension. Rats were studied 4 weeks after unilateral renal artery clipping. Mean blood pressure and plasma renin activity were significantly higher in the hypertensive rats (n = 10 206 +/- mm Hg and 72.4 +/- 20.9 ng/mL-1/h-1, respectively) than in sham-operated controls (n = 10, 136 +/- 3 mm Hg and 3.3 +/- 0.5 ng/mL-1/h, respectively). Northern blot analysis of polyA+ RNA obtained from the kidneys of renal hypertensive rats showed increased levels of renin mRNA in the clipped kidney, whereas a decrease was observed in the unclipped kidney. Plasma renin activity was directly correlated with renin mRNA expression of the poststenotic kidney (r = .94, P < .01). AT1 mRNA expression was lower in both kidneys of the hypertensive rats. This downregulation was specific for the AT1A subtype since the renal expression of the AT1B subtype remained normal in hypertensive rats. The downregulation of the renal AT1A receptor may be due to high circulating angiotensin II levels. This is supported by the significant inverse correlation (r = .71, P < .01) between plasma renin activity and AT1A mRNA expression measured in the clipped kidney of the hypertensive rats.

Prediction of sustained antihypertensive efficacy of chronic captopril therapy: Relationships to immediate blood pressure response and control plasma renin activity

The blood pressure (BP) lowering effect of the orally active angiotensin converting enzyme inhibitor, captopril (SQ14225), was studied in 59 hypertensive patients maintained on a constant sodium intake. Within 2 hours of the first dose of captopril BP fell from 171/107 to a maximum low of 142/92 mm Hg (p less than 0.001), and after 4 to 8 days to treatment BP averaged 145/94 mm Hg (p less than 0.001). The magnitude of BP drop induced by captopril was significantly correlated to baseline plasma renin activity (PRA) both during the acute phase (r = -0.38, p less than 0.01) and after the 4 to 8-day interval (r = -0.33, p less than 0.01). Because of considerable scatter in individual data, renin profiling was not precisely predictive of the immediate or delayed BP response of separate patients. However, the BP levels achieved following the initial dose of captopril were closely correlated to BP measured after 4 to 8 days of therapy, and appeared to have greater predictive value than control PRA of the long-term efficacy of chronic captopril therapy despite marked BP changes occurring in some patients during the intermediate period. Because of these intermediate BP changes, addition of a diuretic to enhance antihypertensive effectiveness of angiotensin blockade should be restrained for several days after initiation of captopril therapy.

Safety and Efficacy of Chronic Therapy with Captopril in Hypertensive Patients: An Update

Abstract: Captopril, an orally active angiotensin‐converting enzyme inhibitor, has been administered to 81 patients with different types of clinical hypertension. Most of the patients had previously uncontrollable high blood pressure. In order to achieve a satisfactory blood pressure control during long‐term captopril therapy, a concomitant decrease in total body sodium was required in more than half of the patients. During our first two years of clinical experience with this new antihypertensive agent, side effects developed in 46.9 per cent of the patients and necessitated the withdrawal of the drug in 23.4 per cent of all patients. Only a few side effects such as hypotensive or syncopal episodes and cold extremities appeared to be due to the chronic blockade of the renin‐angiotensin system. The most frequent and the most serious adverse reactions such as skin rash, altered taste, pancytopenia, and pemphigus foliaceus seemed to be specifically drug related. The incidence of cutaneous and taste problems was markedly higher in patients with impaired renal function in whom retention of captopril has been previously demonstrated. This suggests that the occurrence of adverse reactions to captopril could be lowered in the future by using smaller daily doses and by titrating them according to the renal function.

Accuracy, reproducibility and usefulness of ambulatory blood pressure recording obtained with the Remler system

The Remler M2000, a portable semi-automatic blood pressure recorder, was used to measure ambulatory blood pressure during customary daily activities of normotensive and hypertensive subjects. Systolic and diastolic pressures measured simultaneously by this device and by the conventional auscultatory method were closely related throughout the day, after an acute physical exercise as well as at rest. In unselected, untreated subjects, the average of the recorded pressures was most often lower than pressures measured in the office, but ambulatory pressures could not be predicted from office readings. There was a highly significant correlation between pressure levels determined at a 3 to 4 month interval with both the conventional auscultatory method in the office and the Remler system. In hypertensive patients who were either untreated or treated chronically with beta-blocking agents, diuretics or a combinaton of both drugs, a clear diurnal variation of blood pressure was revealed by the ambulatory recordings, the lowest levels being reached in the early afternoon. Neither this diurnal variation nor blood pressure variability was influenced by antihypertensive therapy. The Remler system was also used to evaluate blood pressure outside the physician’s office in untreated subjects considered by their physician to be hypertensive. The average of blood pressures recorded during the usual daily activities of the subjects were > 140 mmHg for the systolic and > 89 mmHg for the diastolic in only 39% and 44% of them, respectively. Thus, the Remler system provides accurate, reproducible blood pressure profiles in the ambulatory state which are not predictable based on office blood pressure measurements. It seems particularly useful for identifying those patients who, although hypertensive in the physician’s office, remain normotensive during usual daily activities.

Salt-induced hypertension in chronic renal failure: Evidence for a neurogenic mechanism

Abstract We investigated the possibility that blood pressure elevation induced by salt excess may be secondary to a neurogenic mechanism. The compound SK&F 64139 (50 mg/kg) known to inhibit central and peripheral phenylethanolamine N-methytransferase (PNMT) the enzyme necessary for the conversion of norepinephrine to epinephrine, was given by oral gavage to two groups of subtotally nephrectomized rats maintained for five days on either a high salt (HS) or low salt (LS) diet respectively. Blood urea nitrogen (BUN) and hematocrit were not different between the two groups, while body weight and serum Na were significantly higher in the HS animals. Baseline mean blood pressure (BP) was higher in the HS animals (HS 154 ± 4.7 vs LS 121 ± 3.7 mmHg, p

Clinical Application of Treatment with Angiotensin Receptor Antagonists

Today, interruption of the renin—angiotensin system with angiotensin-converting enzyme (ACE) inhibitors represents a well-accepted therapeutic approach to control high blood pressure and to treat patients with congestive heart failure. After more than 10 years of a wide clinical use, ACE inhibitors have not only turned out to be effective in reducing blood pressure of hypertensive patients and in improving survival of patients with congestive failure, they have also produced some interesting metabolic effects, such as raising potassium levels and restoring normal insulin sensitivity. In addition, they can alter the distribution of cardiac output, resulting in marked changes in cardiac, cerebral, and renal tissue perfusion with potential long-term beneficial effects that may go beyond those expected through the reduction of blood pressure. Thus, blood pressure reduction with ACE inhibitors has been shown to provide cardiac protection following myocardial infarction as well as renal protection in patients with diabetic or nondiabetic chronic renal failure. These favorable metabolic and tissue-protecting effects of ACE inhibitors have enlarged considerably their clinical applications.1

Ambulante 24-Stunden Blutdruckmessung

Die ambulante 24-Stunden-Blutdruckmessung ergibt reprasentativere Resultate fur das kardiovaskulare Risiko und das Risiko fur eine Zielorganschadigung als die Blutdruckmessung in der Arztpraxis.

Antihypertensive Agents: Mechanisms of Drug Action

Hypertension is a major risk factor for the development of cardiovascular diseases. There is a direct relationship between blood pressure and the incidence of stroke and coronary events [1]. Even modest elevations in blood pressure (both systolic and diastolic) are associated with an increased health risk. Hypertension also predisposes to left ventricular hypertrophy and chronic renal failure [2, 3].