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G Parati

Publications and source records attributed to G Parati.

At least 109 records · Page 6Linked to original sources
PubMed1995

Ambulatory blood pressure monitoring in the evaluation of antihypertensive treatment: additional information from a large data base.

Aims of our study were i) to compare in a large number of hypertensive subjects the relative effect of antihypertensive treatment on clinic (C) blood pressure (BP) and various ambulatory (A) BP components, and ii) to determine whether antihypertensive treatment affects BP variability. In 266 mild essential hypertensive outpatients (age: 18-78 years) CBP (trough measurements) and ABP (Spacelabs 90202 or 90207) were measured after 3 to 4 weeks of wash-out and after 4 to 8 weeks of treatment with an ACE-inhibitor (n = 135) or a calcium-antagonist (n = 131). ABP recordings were analyzed to obtain average 24 h, day-time (6 a.m. to midnight) and night-time (midnight to 6 a.m.) systolic and diastolic BP values and standard deviations (BP variabilities). Treatment reduced both CBP and ABP. Treatment-induced changes in CBP showed a poor correlation with those in 24h, day- and night-time BP (r never > 0.23) and the correlation was poor also when trough ABP (mean of last 2 h) was considered. Twenty-four hour, day- and night-time BP were similarly reduced by treatment with a direct relationship between the initial BP values and the subsequent BP falls. BP standard deviations were also reduced by treatment in relation to the pretreatment values but the overall reduction was small, limited to the day-time and proportional or less than proportional to the reduction in mean values, with no changes or an increase in variation coefficients. The effects of ACE-inhibitor and calcium-antagonist treatments were superimposable. Our results from a large data base show that antihypertensive treatment effectively reduces all ABP components. The reduction cannot be predicted by the concomitant fall in CBP but it relates to the initial ABP values. Treatment has a limited effect on BP variability, this being the case both for ACE-inhibitors and calcium-antagonists.

Adolescent↗
PubMed1995

Diurnal blood pressure profile in older patients with isolated systolic hypertension. The SYST-EUR Investigators.

This study describes the diurnal blood pressure (BP) profile and identifies its correlates in older patients with isolated systolic hypertension (ISH). The ambulatory BP readings of 408 patients, aged > or = 60 years, with ISH on clinic measurement, enrolled in the placebo run-in phase of the Syst-Eur Trial were examined. The time-weighted 24 h BP, daytime and night-time BP and the cusum-derived crest and trough BP were computed to express the BP level. The daily alteration between the high and low BP span was estimated from the day-night BP difference, the cusum derived circadian alteration magnitude and plot height, as well as the amplitude of the Fourier curve. The 24 h SBP and DBP tended to be higher in men (150 +/- 15/82 +/- 9 mm Hg) than in women (147 +/- 17/79 +/- 10 mm Hg), but the sex difference was only significant for DBP. In multiple regression analysis, the 24 h SBP increased (P < 0.05) by 3 mm Hg for each 10 year increment in age and was also 10 mm Hg higher (P < 0.001) in smokers than in non-smokers; the 24 h DBP was 2 mm Hg higher (P < 0.05) in men than in women and decreased (P < 0.05) by 1.5 mm Hg for each 10 year increment in age. The day-night difference in SBP increased with 2 mm Hg for each 10 mm Hg increase in the conventional pressure, decreased with 5 mm Hg for each 10 year increment in age and was 6 mm Hg higher in smokers than in non-smokers; the day-night difference in diastolic pressure was 2 mm Hg greater in women than in men. We conclude that the main determinants of the diurnal BP variation in older patients with isolated systolic hypertension were sex, age, smoking habits and the level of pressure on conventional measurement.

Age Distribution↗
PubMed1994

Clinical trials with ambulatory blood pressure monitoring: fewer patients needed? Syst-Eur Investigators.

We have tested the concept that fewer patients are needed in trials of antihypertensive treatment if blood pressure is measured by ambulatory monitoring rather than by conventional sphygmomanometry. 233 patients (> or = 60 years old) with isolated systolic hypertension were randomly allocated placebo (n = 119) or active treatment (n = 114). Blood pressure measurements were compared by Wilcoxon's test and blood pressure profiles by ANOVA. With either method of measurement, the same number of patients (40 in each treatment group) was required to show a reduction after 1 year in clinic (13/8 mm Hg) or average blood pressure over 24 h (9/5 mm Hg). To detect that the decrease in systolic pressure was not steadily maintained through the day, 40 patients in each treatment group were needed for blood pressure profiles made up of 4-hourly or 2-hourly means and 60 for profiles of 1-hourly means. For diastolic pressure, the corresponding numbers were 80, 100, and more than the number of available patients, respectively. We conclude that parallel-group trials focusing on the average blood pressure over 24 h, rather than on conventionally measured blood pressure, cannot economise on sample size. Moreover, trials studying the full course of blood pressure throughout the day, require more--not fewer--patients than studies of only the conventional or average 24 h blood pressure.

Aged↗
PubMed1994

Blood pressure reduction and end-organ damage in hypertension.

VALUE OF AMBULATORY BLOOD PRESSURE MONITORING: Studies that have used ambulatory blood pressure monitoring techniques have shown that the average 24-h or daytime blood pressure values are more closely related to the end-organ damage associated with hypertension than are isolated office readings. IMPORTANCE OF BLOOD PRESSURE VARIABILITY IN PROGNOSIS: More recently, blood pressure variability, measured as the overall 24-h blood pressure standard deviation, has been shown to have a significant relationship to end-organ damage in hypertensive patients. The potential clinical relevance of blood pressure variability has been strengthened in a recent prospective study. The possible prognostic value of blood pressure variability has practical implications for antihypertensive treatment; it may mean, for example, that the optimal antihypertensive drug should reduce not only the mean 24-h values but also the degree of fluctuation in blood pressure. This is more likely to occur with long-acting drugs, which induce a more balanced reduction in blood pressure throughout the 24 h. USE OF THE TROUGH:PEAK RATIO: A proposed measure of a balanced 24-h blood pressure effect is the trough:peak ratio of the blood pressure fall. This ratio can be obtained by clinic blood pressure measurements but ambulatory blood pressure monitoring offers some distinct advantages. One of these advantages is that by revealing the possibility of an excessive fall in blood pressure at the time of the peak effect or an uncontrolled rise at the trough, ambulatory monitoring can also reveal the possible impact of pharmacological treatment on 24-h blood pressure variability.

Antihypertensive Agents↗
PubMed1994

Beta-adrenergic blocking treatment and 24-hour baroreflex sensitivity in essential hypertensive patients.

We dynamically evaluated the effects of beta-blockade on the sensitivity of arterial baroreflex control of heart rate in 10 mild or moderate essential hypertensive patients in whom blood pressure was recorded intra-arterially for 24 hours in ambulatory conditions. Twenty-four-hour baroreflex sensitivity was assessed by both (1) a time-domain approach based on the calculation of the slope of the regression line between linearly related progressive increases in systolic blood pressure and pulse interval (+PI/+SBP sequences) and decreases in systolic blood pressure and pulse interval (-PI/-SBP sequences) and (2) a frequency-domain approach, ie, the ratio between the spectral powers of pulse interval and systolic blood pressure around 0.1 Hz (alpha coefficient). Data were obtained before and after 1 month of administration of either acebutolol (n = 5) or labetalol (n = 5). Before treatment, the 24-hour average slopes of the +PI/+SBP and -PI/-SBP sequences were 4.36 +/- 0.32 and 4.05 +/- 0.27 ms/mm Hg, respectively, while the alpha coefficient was 7.78 +/- 0.7 ms/mm Hg. After beta-blockade, these values were increased by 25.3 +/- 6.8%, 25.0 +/- 8.0%, and 32.1 +/- 9.3%, respectively (P < .01 for all values). Thus, beta-blockers potentiate baroreflex sensitivity in daily life. Time-domain and frequency-domain methods yielded superimposable results in dynamically evaluating 24-hour baroreflex sensitivity and its changes after beta-blockade.

Acebutolol↗
PubMed1994

Clinical use of ambulatory blood pressure monitoring: a critical appraisal.

Traditional sphygmomanometric techniques are heavily affected by the 'white-coat' effect and cannot be used to assess blood pressure variability over the 24h period. These limitations can be overcome in part using ambulatory monitoring, which (1) quantifies both the mean and the variability of blood pressure over 24h, including blood pressure fluctuations between day and night, (2) does not trigger any alerting reaction in the patient, (3) provides reproducible 24h blood pressure means and (4) allows the action of antihypertensive drugs to be assessed over 24h without interference from a placebo effect. Moreover, ambulatory blood pressure values are more closely related to the end-organ damage associated with hypertension than are isolated clinic readings. However, the limited accuracy of ambulatory monitoring in ambulant individuals, the lack of normal reference values for 24h blood pressure and the need for a longitudinal demonstration of the prognostic value of the technique do not permit the recommendation of its widespread use in clinical hypertension. Although the clinical use of ambulatory monitoring should be restricted to selected cases, there is general agreement on its usefulness in clinical pharmacology trials and in studies aimed at assessing cardiovascular regulation through the analysis of 24h blood pressure and heart rate fluctuations.

Antihypertensive Agents↗
PubMed1994

Blood pressure variability and organ damage.

Several studies have now shown that hypertension-induced end-organ damage is more closely related to 24-h average blood pressure than to clinic measurements. Furthermore, the degree of variability of blood pressure during a 24-h period bears a relation to organ damage that is independent of average blood pressure value. The measurement of blood pressure variability is a complex task, however, because data from automatic ambulatory blood pressure monitoring should be interpreted with caution, especially if the interval between blood pressure measurements is more than 15 min, and different types of blood pressure variability (e.g., short-term and long-term) can make calculation of variability by standard deviation of 24-h blood pressure values difficult, which further complicates measurement procedures and interpretation. Evidence is growing to suggest that blood pressure variability in hypertension is clinically significant. We have recently shown that over a 7.5-year period, end-organ damage is independently related to the initial blood pressure variability. Although information on the effect of antihypertensive treatment on 24-h blood pressure variability is limited, the available data suggest more of an effect on 24-h average blood pressure levels than on 24-h blood pressure changes. Further studies should investigate treatment effects on different types of blood pressure variability and the impact of treatment on patient protection and prognosis.

Antihypertensive Agents↗
PubMed1994

[Hemodynamics and pressure variability in isolated systolic hypertension].

Isolated systolic hypertension is a common feature in aged individuals and it has been associated with an increased cardiovascular mortality and morbidity. More recently it has been shown that this condition is characterized by peculiar abnormalities of arterial vessels. For example isolated systolic hypertension is associated with a reduction in arterial compliance evident both in muscle arteries, like the radial one, and in elastic arteries, like the carotid one. On the other side cardiovascular homeostasis is markedly deranged and blood pressure variability more marked than in age matched normotensive subjects. Finally, 24-hour blood pressure monitoring has allowed to exclude that isolated systolic hypertension might be merely linked to an exaggerated alarm reaction, showing that blood pressure is elevated along the whole 24-hour blood pressure profile.

Hemodynamics↗
PubMed1994

Ambulatory blood pressure monitoring in the evaluation of antihypertensive drugs.

CLINIC VERSUS AMBULATORY BLOOD PRESSURE MEASUREMENT: Clinic blood pressure measurements do not give the best estimate of the efficacy of antihypertensive drugs because (1) they provide readings for one time-point only, (2) they are subject to a 'white-coat' effect and also show a significant placebo effect and (3) they are poorly reproducible. Ambulatory blood pressure monitoring overcomes these problems and offers the possibility of obtaining reliable, reproducible and detailed information on the time-course and magnitude of the effect of antihypertensive treatment on blood pressure over 24 h. MEAN 24-H VERSUS MEAN HOURLY AMBULATORY BLOOD PRESSURE VALUES: Compared with mean 24-h values, reproducibility is poorer for mean hourly ambulatory values, which show greater variability when tested under different conditions. Thus, caution must be exercised when the effects of antihypertensive drugs on hourly blood pressure profiles are analysed and the trough:peak ratio is calculated. FURTHER PROBLEMS WITH AMBULATORY MONITORING: There are further reasons for caution: (1) ambulatory blood pressure readings can be inaccurate, (2) there is only preliminary information on normal reference values and (3) there have been no longitudinal studies demonstrating the prognostic value of ambulatory blood pressure monitoring, which introduces uncertainty into attempts to evaluate the optimal effect of antihypertensive treatment by this method. CONCLUSIONS: These limitations do not detract from the use of ambulatory blood pressure monitoring in drug studies, but they do suggest that this measurement technique should not be used routinely for assessing antihypertensive treatment in clinical practice.

Antihypertensive Agents↗
PubMed1994

Ambulatory pressure decreases on long-term placebo treatment in older patients with isolated systolic hypertension. Syst-Eur Investigators.

OBJECTIVE: This long-term study investigated the widely accepted hypothesis that ambulatory pressure does not decrease in patients given placebo. METHODS: One hundred and twelve older (> or = 60 years) outpatients with isolated systolic hypertension were recruited. Treatment consisted of a placebo during a 3-month baseline period and long-term follow-up. RESULTS: At baseline, on placebo treatment, clinic systolic/diastolic (SBP/DBP) blood pressure (+/- SD) averaged 176 +/- 12/86 +/- 7 mmHg and 24-h SBP/DBP 151 +/- 15/81 +/- 10 mmHg. These pressures were unaltered in 51 patients in whom the baseline measurements were repeated after a further month on placebo. After the 112 patients had received placebo for 1 year (median), clinic SBP/DBP fell by 6.6 +/- 15.9 (P < 0.001)/1.4 +/- 7.4 (P = 0.06)mmHg and 24-h SBP by 2.4 +/- 10.7 mmHg (P < 0.05), whereas 24-h DBP did not change significantly. The 24-h SBP decreased more with higher baseline level and longer follow-up (5-21 months). CONCLUSIONS: These findings in older patients with isolated systolic hypertension suggest that in long-term studies the ambulatory pressure may slightly but significantly decrease on a placebo. Like those using conventional sphygmomanometry, long-term studies using non-invasive ambulatory monitoring require a placebo-controlled design.

Aged↗
PubMed1994

[Variability of heart rate in hypertensive patients: clinical and physiopathological implications].

Heart rate variability has been investigated in essential hypertension by studies combining 24-hour ambulatory blood pressure and heart rate monitoring techniques. These studies have shown a clear circadian pattern of heart rate fluctuations. By means of spectral analysis it has also been possible to describe the changes over the 24 hours of specific heart rate fluctuations occurring at various frequencies, which, at least in mild to moderate hypertensives, are not different from those of normotensive subjects. Laboratory studies have also shown the important role exerted by arterial baroreflexes in modulating heart rate variability. Finally, recent methods have been developed to dynamically monitor changes in baroreflex sensitivity in daily life conditions through the time domain or frequency domain analysis of spontaneous blood pressure and heart rate fluctuations.

Activities of Daily Living↗
PubMed1994

Blood pressure variability: clinical implications and effects of antihypertensive treatment.

HYPOTHESIS ON RELATIONSHIP BETWEEN BLOOD PRESSURE VARIABILITY AND END-ORGAN DAMAGE: Several studies have shown that the cardiovascular complications of hypertension are more closely related to ambulatory 24-h or daytime average blood pressure than to office readings. A few studies have also provided evidence that in hypertensive patients, not only average ambulatory blood pressure but also the degree of blood pressure variability is significantly and independently related to the end-organ damage associated with hypertension. LIMITATIONS OF PREVIOUS STUDIES: A common limitation of previous studies is that they were based on cross-sectional or retrospective observations, so that the correlative evidence they provide does not allow the relationship between blood pressure variability and end-organ damage to be interpreted causally. EVIDENCE FROM RECENT STUDIES: Recent evidence from follow-up observations has strongly supported the hypothesis that blood pressure variability is prognostically important in hypertensive patients. These findings suggest that optimal antihypertensive treatment should aim not only to reduce mean blood pressure levels, but also to reduce the degree of blood pressure fluctuation. EFFECTS OF ANTIHYPERTENSIVE DRUGS: Unfortunately, while most new antihypertensive drugs seem to be effective in reducing 24-h mean blood pressure levels, they are frequently unable to reduce 24-h blood pressure variability, which is often increased during treatment when expressed in normalized units. The development of drugs that guarantee a constant and uniform reduction in blood pressure over 24 h may, in principle, offer a further advantage by preventing the increase in 24-h blood pressure fluctuations that may follow the administration of short-acting antihypertensive agents. TROUGH: PEAK MEASUREMENTS OF BLOOD PRESSURE: The trough: peak ratio, proposed as an arithmetic indicator of the duration of the antihypertensive effect of a drug, may be a useful measure of the occurrence of a smooth reduction in blood pressure over 24 h. The possibility of obtaining an additional reduction in cardiovascular risk for hypertensive patients by minimizing the net trough: peak effect of antihypertensive drugs is thus an important issue for future studies.

Antihypertensive Agents↗
PubMed1994

Ambulatory blood pressure monitoring in the diagnosis of hypertension and evaluation of antihypertensive drug efficacy.

Ambulatory blood pressure monitoring is invaluable in the assessment of the efficacy of antihypertensive drug treatment because it allows the reduction of blood pressure to be confirmed within the context of daily life. It also allows the determination of whether treatment produces an even blood pressure reduction over the 24-hour period or whether it is characterized by an uneven profile, for example, a precipitous fall early after administration of the drug and a later return towards elevated blood pressure values. A lack of information on prognostic and normal values does not permit quantification of the optimal blood pressure reduction to be achieved throughout the monitoring period. It is agreed, however, that the decrease should take into consideration both the elevated daytime and the reduced night-time blood pressures, and that peak blood pressure values associated with physical and emotional activities as well as the overall variability of blood pressure should also be reduced. Finally, ambulatory blood pressure monitoring is virtually devoid of the placebo effect, and the 24-hour average blood pressure data derived by this method are more reproducible than isolated blood pressure values taken by sphygmomanometry. This offers distinct advantages for studies designed to evaluate the antihypertensive effect of new drugs.

Antihypertensive Agents↗
PubMed1994

Increase in blood pressure reproducibility by repeated semi-automatic blood pressure measurements in the clinic environment.

OBJECTIVE: To evaluate whether increasing the number of blood pressure readings obtained in the clinic environment increases the blood pressure reproducibility. PATIENTS: Thirteen mild essential hypertensive patients studied in the outpatient clinics, following withdrawal of antihypertensive treatment for 4 weeks. METHODS: The systolic and diastolic blood pressures were measured three times, using a mercury sphygmomanometer, with the patient in the sitting position. Measurements were then performed with the patient in the lying position using an oscillometric device (SpaceLabs 90202 or 90207). The device was operated semi-automatically at 3-min intervals until 25 readings had been collected. The same procedure was repeated 4 weeks later. The systolic blood pressure, diastolic blood pressure and heart rate were averaged by considering a progressively greater number of readings, from 1 to 25. The reciprocal of the standard deviation (1/SD) of the mean difference after 4 weeks was taken as the measure of reproducibility. RESULTS: 1/SD increased progressively as the number of semi-automatic blood pressure readings from which the average was calculated increased. For a similar number of blood pressure readings the reproducibility was similar for semi-automatic readings to that for automatic readings obtained by 24-h ambulatory blood pressure monitoring. CONCLUSION: Multiple blood pressure readings obtained semi-automatically in the outpatient clinics increase blood pressure reproducibility and make the value similar to that obtained by ambulatory blood pressure monitoring. The advantage of an increase in reproducibility for studies on antihypertensive drugs thus depends on the number of readings, and can also be obtained by semi-automatic measurements in the clinic environment.

Adult↗
PubMed1993

Calcium antagonists in the treatment of arterial hypertension.

Calcium antagonists are widely used antihypertensive agents whose hemodynamic effects consist of a reduction in blood pressure and peripheral vascular resistance that is associated, in case of short-term administration, with a reflex increase in heart rate and cardiac output. These compounds exert several additional positive effects besides blood pressure reduction. Among them, calcium antagonists exert their antihypertensive effect without negatively interfering with both central and reflex neural control of circulation. The only change in baroreflex function observed during the administration of these compounds is a resetting of the baroreflex toward the lower blood pressure values achieved by treatment. New calcium antagonists of the dihydropyridine type are characterized by a greater vascular selectivity, and by the ability to exert a persistent blood pressure reduction throughout the 24 hours when administered in a single oral dose. The latter feature can be properly assessed by means of ambulatory blood pressure monitoring techniques.

Calcium Channel Blockers↗
PubMed1993

Clinical value of ambulatory blood pressure monitoring.

Although office blood pressure measurement may be predictive of cardiovascular complications, it still has several limitations: first, the accuracy of its predictions is limited; second, the stress reaction it causes may lead to an overestimation of the need for treatment and to an underestimation of the therapeutic response in some patients; and third, because of this 'white-coat' reaction and the wide variation in blood pressure over 24 h, office blood pressure can only be an approximate reflection of 24-h average blood pressure values both during and in the absence of treatment. The alternative method of ambulatory blood pressure monitoring may represent a valuable approach in the clinical management of hypertension. Values derived by this method are largely devoid of the consequences of the 'white-coat' reaction and are more closely correlated to the organ damage associated with hypertension than those derived from office blood pressure measurement. However, longitudinal studies are needed to demonstrate whether ambulatory blood pressure monitoring is truly prognostically superior to the traditional method, and to determine precisely which are the blood pressure values within the 24-h period on which to base the diagnosis of hypertension to assess more accurately the efficacy of antihypertensive treatment. However, there is the suggestion that optimal blood pressure control probably consists of an even reduction of both daytime and night-time values, and that the wide variations in blood pressure that occur throughout 24 h should probably also be reduced and maintained on a long-term basis.

Blood Pressure Determination↗
PubMed1993

Prognostic value of 24-hour blood pressure variability.

OBJECTIVES: Evaluation of the prognostic value of 24-h blood pressure averages and 24-h blood pressure variability. DESIGN: After an initial thorough clinical and laboratory evaluation which included 24-h continuous ambulatory blood pressure monitoring, a group of hypertensive patients were re-examined after an average of 7.4 years. End-organ damage at the follow-up visit was related to different measures of blood pressure levels and variability obtained at the initial or the follow-up visit or both. METHODS: Seventy-three patients with essential hypertension of variable severity, in whom ambulatory blood pressure was monitored intra-arterially for 24 h (Oxford technique) were re-examined at a follow-up visit (including echocardiographic assessment of left ventricular mass index) 1-13 years later (mean 7.4 years). The severity of end-organ damage was quantified by a score and related to clinic blood pressure at follow-up and to (1) clinic blood pressure, (2) 24-h blood pressure mean, (3) 24-h short-term and long-term blood pressure variability, and (4) end-organ damage, all assessed at the initial visit (multiple regression analysis). RESULTS: The set of independent variables considered was significantly related to end-organ damage at follow-up (R = 0.51). The individual variables most important in determining end-organ damage at follow-up were clinic blood pressure at the follow-up visit (P < 0.01), the initial level of end-organ damage (P < 0.05) and long-term blood pressure variability (among half-hour standard deviation of 24-h mean blood pressure) at the initial evaluation (P < 0.05). The prognostic individual weight of the other haemodynamic parameters considered was less and not statistically significant. CONCLUSIONS: The results confirm that the level of blood pressure achieved by treatment and the degree of end-organ damage at the time of initial evaluation are important determinants of future end-organ damage related to hypertension. They also constitute the first longitudinal evidence that the cardiovascular complications of hypertension may depend on the degree of 24-h blood pressure variability.

Adult↗