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Biomedical subjects

G Mancia

Publications and source records attributed to G Mancia.

At least 325 records · Page 18Linked to original sources
PubMed1993

Radial artery compliance in essential hypertension: effects of antihypertensive therapy with lacidipine.

OBJECTIVE: To evaluate the effects of antihypertensive therapy with lacidipine on the increase in radial artery compliance observed in mild essential hypertensive patients. METHODS: The study was performed in eight mild to moderate essential hypertensive patients in whom clinic blood pressure, radial artery diameter and radial artery compliance were evaluated before and after 3 months' administration of lacidipine, at a single daily dose of 4 mg. Radial artery diameter and compliance were evaluated by means of a high precision echo-tracking device able to assess arterial compliance over the blood pressure oscillations that characterize the cardiac cycle. RESULTS: Lacidipine treatment caused a significant reduction in clinic systolic and diastolic blood pressure, while the heart rate was not modified by the drug. Radial artery diameter and compliance were both reduced by lacidipine over the entire systolodiastolic blood pressure range. CONCLUSIONS: Chronic administration of lacidipine seems to reverse the increase in compliance observed in essential hypertension at the radial artery level. We suggest that lacidipine treatment can reverse an increase in the smooth muscle component in the arterial wall induced by hypertension.

Adult↗
PubMed1993

RAA system and cardiovascular control in normal subjects, hypertensives and patients with congestive heart failure.

The involvement of the renin-angiotensin-aldosterone (RAA) system, particularly angiotensin II, in the pathogenesis of hypertension is widely acknowledged and is supported by several observations: the RAA system has been shown to be critically involved in the development of some experimental hypertensions; activation of the RAA system appears to be the crucial factor involved in the maintenance of the BP elevation in some antihypertensive patients; while drugs which interfere with the production of angiotensin II reduce BP in a large number of hypertensive patients. It is now clear that the chronic BP elevations caused by circulating (and perhaps locally produced) angiotension II may have adverse effects on organ function and protection: for example, induction of cardiac hypertrophy and vascular hypertrophy and/or hyperplasia, reduction of arterial compliance and reduction in vagal tone and facilitation of sympathetic activity on cardiac and vascular targets. At the cardiac level, the renin-angiotensin sympathetic interaction may enhance electrical instability, thereby favouring arrhythmias and increasing mortality after a myocardial infarction. It finally enhances coronary vasoconstriction in man, producing or favouring myocardial ischaemia.

Angiotensin II↗
PubMed1993

Spectral analysis of 24 h blood pressure recordings.

Spectral analysis of blood pressure and heart rate signals allows overall blood pressure and heart rate variabilities to be split into their different frequency components. When used to analyze 24 h discontinuous blood pressure recordings, the low sampling frequency that characterizes these devices allows only the slow fluctuations in day and night blood pressure to be adequately described by the spectral approach. Conversely, spectral analysis of continuous blood pressure recordings provides information both on fast and slow changes in blood pressure and heart rate. Because blood pressure and heart rate powers are characterized by a 1/f distribution over the 24 h, slow fluctuations in blood pressure and heart rate contribute most importantly to 24 h variance, while faster components provide only a minor contribution. However, spectral analysis of the latter has raised considerable interest due to the possible association of these components with cardiovascular regulatory mechanisms. It is now possible to perform 24 h dynamic spectral analysis of blood pressure and heart rate on continuous blood pressure recordings obtained noninvasively by a finger pressure device.

Blood Pressure↗
PubMed1993

Ambulatory blood pressure monitoring in the design of studies on antihypertensive drug efficacy.

Ambulatory blood pressure monitoring (ABPM) provides advantages for studies of the efficacy of antihypertensive drugs in addition to demonstrating antihypertensive effects in daily life conditions. For example, ABPM is devoid of the "white coat" effect and can thus more precisely estimate the relative proportion of responders and nonresponders to treatment. It also may reduce the study size because of the greater reproducibility of 24 h average blood pressure (BP) (as compared to clinic BP) and the lack of a substantial placebo effect, which eliminates the need for a placebo group. Some disadvantages exist, including the inability of automatic ABPM to consistently provide accurate BP readings and to estimate BP variability. Finally, hourly average BPs are less reproducible than their average 24 h counterpart, which may make it more difficult to statistically demonstrate an antihypertensive effect throughout the 24 h. Some of these disadvantages, however, may be reduced in the near future by new ABPM devices.

Ambulatory Care↗
PubMed1993

Treating hypertension in the elderly.

Hypertension is a common problem in the elderly, with a prevalence of about 50%. The risk of cardiovascular disease and death is increased in hypertensive patients aged 60-79 years, whereas this increased risk seems to be diminished or even non-existent in those aged > or = 80 years. Antihypertensive drug treatment has been shown to be beneficial for most elderly patients but whether this is also true for the oldest patients is less clear. Treatment is more difficult in the elderly than in the middle aged or young because of the structural and functional alterations of the cardiovascular system associated with ageing (in particular the impairment of BP homeostasis), which contraindicate some drugs and impose a cautious use of the remaining ones. Isolated systolic hypertension increases the cardiovascular risk but we lack data on the efficacy of treatment in this group.

Age Factors↗
PubMed1993

Ambulatory blood pressure monitoring in elderly hypertensive patients.

Ambulatory blood pressure monitoring (ABPM) has been shown to provide a reliable estimation of hourly blood pressure values over the 24 hours. Favourable features of this technique are the lack of alerting reaction to automatic blood pressure readings, at variance from what usually occurs when blood pressure is measured in the doctor's office, and the ability of ABPM to provide information on the 24 hour blood pressure profile without interfering with the physiological nocturnal hypotension. Although automatic blood pressure readings obtained in free-moving subjects are not always accurate, ABPM has been shown to represent a useful approach to evaluate the efficacy of antihypertensive drugs, as it allows to compare the 24 hour blood pressure profile obtained before and during treatment. Its feasibility to this aim is emphasized by the reproducibility of 24 hour ambulatory blood pressure profiles, which do not show any placebo effect. ABPM has been also employed to investigate 24 hour blood pressure fluctuations and to monitor the antihypertensive treatment in elderly hypertensives, in whom the evaluation of the actual time-course of the drug-induced blood pressure reduction over the day and night represents a crucial problem.

Aged↗
PubMed1992

Clinical value of blood pressure measurements: focus on ambulatory blood pressures.

Because clinic blood pressure values are compromised by 2 major limitations--the alerting reaction to clinic measurements and the spontaneous blood pressure variability--they have only a limited correlation with average 24-hour blood pressure values. Whether the latter should be employed routinely in substitution for, or in addition to, traditional blood pressure measurements has not yet been determined, however. To date, average 24-hour blood pressure values have been shown to correlate more closely than clinic blood pressure values with the organ damage of hypertension. A correlation with organ damage has been shown also for a number of blood pressure values within the 24 hours. Nevertheless, the clinical importance of 24-hour blood pressure and blood pressure variability has never been confirmed by prospective controlled studies. This information needs to be obtained before this approach is routinely employed in the clinical practice.

Ambulatory Care↗
PubMed1992

Evaluation of the antihypertensive effect of once-a-day trandolapril by 24-hour ambulatory blood pressure monitoring. The Italian Trandolapril Study Group.

The aim of this study was to evaluate the effects of trandolapril on 24-hour blood pressure in patients with mild-to-moderate essential hypertension. After a washout period of 4 weeks, 42 patients were randomized to receive 2 mg of trandolapril once daily and 20 to receive placebo in a double-blind fashion for 6 weeks. This was followed by a second washout period of 4 weeks. At the end of each period, clinic blood pressure was assessed at 24 hours after the last dose and 24-hour ambulatory blood pressure was measured noninvasively, taking blood pressure readings every 15 minutes during the day and every 20 minutes during the night. Two patients were dropped out before any blood pressure evaluation under treatment. Analysis of ambulatory blood pressure was performed in 48 patients who met the criteria for the minimal number of ambulatory blood pressure data (2 values per hour during the day and 1 value per hour in the night). In the trandolapril-treated group (n = 41) clinic systolic/diastolic blood pressures were 159.8 +/- 2.0/102.4 +/- 0.8, 146.8 +/- 2.3/94.8 +/- 1.1, and 155.7 +/- 2.0/99.2 +/- 0.7 mm Hg in the pretreatment, treatment, and post-treatment periods, respectively. The corresponding values for 24-hour mean blood pressure (n = 31) were 139.5 +/- 1.9/91.2 +/- 1.5, 131.0 +/- 2.0/84.3 +/- 1.2, and 139.7 +/- 1.8/90.9 +/- 1.1 mmHg. The differences between the lower treatment, versus the higher pre- and post-treatment, values were all statistically significant (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Reflex cardiovascular control in congestive heart failure.

This article reviews evidence that the reflex control of the cardiovascular system provided by negative feedback mechanisms is impaired in congestive heart failure (CHF). The impairment involves vagal and sympathetic modulation of the heart exerted by arterial baroreceptors. It also affects baroreceptor control of blood pressure and peripheral vascular resistance, as well as the cardiopulmonary receptor's ability to modulate sympathetic activity. The degree of such impairment is most marked in severe CHF but is also apparent, to a minor degree, in mild heart failure. Reflex impairment is due to a reduction in the receptor signal, but other factor under investigation are probably also involved. Digoxin and other pharmacologic treatments of CHF improve reflex function, thereby facilitating a reduction in the elevated sympathetic activity and a stepping up of the reduced vagal activity typical of CHF. This may be relevant to a patient's prognosis.

Animals↗
PubMed1992

Cardiopulmonary receptor and arterial baroreceptor reflexes after acute myocardial infarction.

The baroreceptor-heart rate reflex in human is impaired 2 days after a myocardial infarction but it improves 10 days after the acute coronary event. This study investigated whether (1) the baroreceptor-heart rate reflex improvement takes the reflex back to normal, and (2) the cardiopulmonary reflex is affected by myocardial infarction. In subjects studied 8 to 11 days after a transmural anterior or inferior myocardial infarction the baroreceptor-heart rate reflex sensitivity (slope of the linear regression between negative neck chamber pressures and lengthenings in RR interval) was similar to that seen in control subjects (-6.2 +/- 0.8 vs -6.0 +/- 0.6 ms/mm Hg, mean +/- SEM) and did not change when reassessed 10 days later. In contrast, the cardiopulmonary reflex sensitivity (changes in forearm vascular resistance induced by changing central venous pressure through nonhypotensive lower body suction and leg raising) was markedly less in subjects studied 8 to 11 days after myocardial infarction than in control subjects; the reduction amounted to 58.1 +/- 8% (p less than 0.01). The cardiopulmonary reflex sensitivity greatly improved when reassessed 28 to 45 days later. Thus, the baroreflex is normal about 10 days after myocardial infarction. This condition markedly impairs the cardiopulmonary reflex, but the impairment is also transient.

Blood Pressure↗
PubMed1992

Effect of detraining on the cardiopulmonary reflex in professional runners and hammer throwers.

In professional athletes with marked cardiac hypertrophy, reflex influences originating from cardiopulmonary receptors are impaired. To determine whether the reflex is restored after termination of physical training and regression of cardiac hypertrophy 8 former athletes (age 31 +/- 6 years, mean +/- SD) who stopped agonistic activity for 5 +/- 1 years were compared with 15 sedentary subjects (27 +/- 7 years) and 19 active professional athletes (22 +/- 7 years). Cardiopulmonary receptor stimulation and deactivation were obtained by increasing and reducing left ventricular end-diastolic diameter (echocardiography) through leg raising and nonhypotensive lower body negative pressure, respectively. Left ventricular mass index (echocardiography) was markedly and significantly (p less than 0.01) greater in athletes (135 +/- 6 g/m2) than in former athletes (105 +/- 4 g/m2) whose value was similar to that of sedentary subjects (98 +/- 4 g/m2). The reduction in forearm vascular resistance and plasma norepinephrine induced by increasing left ventricular end-diastolic diameter was 24 and 23% less in athletes than in former athletes whose responses were similar to those of sedentary subjects. This was the case also for the responses induced by reducing left ventricular end-diastolic diameter. In contrast, the hemodynamic responses to cold pressor test were similar in the 3 groups. It is concluded that the impairment of the cardiopulmonary reflex observed in athletes is largely reversible when physical training is terminated. This may be due to regression of left ventricular hypertrophy.

Adaptation, Physiological↗
PubMed1992

Noninvasive automatic blood pressure monitoring does not attenuate nighttime hypotension. Evidence from 24 h intraarterial blood pressure monitoring.

Automatic ambulatory blood pressure monitoring makes use of repeated cuff inflations throughout the day and night. This may interfere with the cardiovascular effects of sleep and thus alter the 24 h blood pressure profile. The possibility that intermittent automatic blood pressure measurements prevent nocturnal hypotension was examined in 17 mild or moderate essential hypertensive patients in whom blood pressure was recorded intraarterially for 48 h by the Oxford technique. During the first or the second 24 h period, blood pressure was also monitored noninvasively by the SpaceLabs (Redmond, WA) 5300 (n = 10) and by the Sandoz Pressure System SPS 1558 (Lavanchy Electronique, Prilly, Switzerland) (n = 7) devices, automatic measurements being performed at 15 min intervals during the day and at 30 min intervals during the night. Separate computer analysis of 24 h intraarterial tracings obtained in absence and in concomitance of contralateral automatic blood pressure monitoring showed that the occurrence of automatic measurements had not interfered with the day-night intraarterial blood pressure and heart rate profiles. Thus the frequent cuff inflations that characterize automatic blood pressure monitoring do not attenuate nighttime hypotension and bradycardia. This finding supports use of the noninvasive approach in assessing blood pressure profiles.

Adult↗
PubMed1992

Ambulatory blood pressure monitoring and antihypertensive treatment.

This paper outlines the advantages of ambulatory blood pressure monitoring (ABPM) in the evaluation of the efficacy of antihypertensive drugs. The main advantage is that ABPM allows the antihypertensive effect of a drug or drug regimen to be determined in daily life conditions and to uncover whether the treatment employed is associated with untoward hypotensive episodes. Furthermore, ABPM facilitates the design of studies on antihypertensive drug efficacy because the 24 h mean blood pressure is devoid of a placebo effect and its reproducibility is much greater than office blood pressure. This has permitted demonstration of the efficacy of several antihypertensive drug regimens, including diuretic studies, based on relatively small numbers of subjects. A further advantage of ABPM is that it allows drug treatment efficacy to be evaluated in relation to blood pressure variability, another possible determinant of the organ damage related to hypertension.

Antihypertensive Agents↗