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Biomedical subjects

G Mancia

Publications and source records attributed to G Mancia.

At least 217 records · Page 12Linked to original sources
PubMed1996

Difference between office and ambulatory blood pressure and response to antihypertensive treatment.

OBJECTIVE: To investigate whether a clinic-ambulatory blood pressure difference persists with time under active drug treatment or placebo and to determine whether and how it interferes with the evaluation of the efficacy of antihypertensive treatment. DESIGN AND METHODS: In 382 mild or moderate essential hypertensive patients (mean age +/- SD 51.5 +/- 9.2 years) clinic and ambulatory (SpaceLabs 90207 device) blood pressures were measured twice, under baseline conditions and after 4-8 weeks of antihypertensive treatment by calcium antagonists or angiotensin converting enzyme inhibitors (n = 266) or of placebo administration (n = 116). In each patient the difference between clinic and daytime average blood pressure was taken as a surrogate measure of the magnitude of the 'white-coat effect', separately for systolic and diastolic blood pressures. The changes in this difference induced by treatment and by placebo and the relationship between the blood pressure changes induced by drug treatment and by placebo and the magnitude of the difference before and during treatment or placebo, respectively, were computed. RESULTS: Before drug treatment, the difference was 16.6 +/- 13.6 and 10.1 +/- 7.9 mmHg for systolic and diastolic blood pressures, respectively. During treatment the corresponding values were 11.9 +/- 14.2 and 6.8 +/- 9.2 mmHg; both of the reductions were statistically significant. Both for systolic and for diastolic blood pressure, the reduction in clinic blood pressure caused by treatment was directly related to the clinic-ambulatory difference before treatment, but inversely related to the magnitude of that difference persisting during treatment. The clinic-ambulatory blood pressure difference observed before placebo was attenuated during placebo, the magnitude of the attenuation being similar to that found under drug treatment. No significant difference between clinic and daytime average heart rate was ever observed before and during active treatment or placebo. CONCLUSIONS: A considerable clinic-ambulatory blood pressure difference persists during several weeks of antihypertensive treatment, but its magnitude is significantly attenuated. This leads to an overestimation of the effectiveness of antihypertensive treatment when this is assessed by clinic blood pressure measurements only. This overestimation is greater in subjects with an initially greater difference because in these subjects the subsequent attenuation is greater. Because similar phenomena are observed with placebo, the attenuation in the difference during drug treatment is likely to reflect merely habituation to clinic blood pressure measurements with time.

Ambulatory Care↗
PubMed1996

Benefit versus risk of calcium antagonists in hypertensive patients with concomitant risk factors.

BLOOD PRESSURE REDUCTION AND CARDIOVASCULAR MORBIDITY AND MORTALITY: Several hypertension trials have shown that antihypertensive treatment can reduce the cardiovascular morbidity and mortality accompanying this condition. They have also shown, however, that the reduction does not entirely normalize the risk of hypertensive patients. STRATEGIES TO IMPROVE THE BENEFIT OF ANTIHYPERTENSIVE TREATMENT: Although some of the risk of the hypertensive patient may prove to be irreversible, pathophysiological and clinical evidence obtained in recent years suggests that some modifications to antihypertensive treatment strategies might increase the benefit. For example, greater use of drugs such as calcium antagonists and angiotensin converting enzyme (ACE) inhibitors as first-line agents might bring greater benefits, because some properties of these drugs which are additive to their blood pressure lowering effects, such as regression of cardiovascular structural changes, nephroprotection and delay of atherogenesis, may provide a degree of protection against target-organ damage. ONGOING CLINICAL TRIALS AND THE INTERNATIONAL NIFEDIPINE (GITS) GASTROINTESTINAL SYSTEM STUDY OF INTERVENTION AS A GOAL IN HYPERTENSIVE TREATMENT (INSIGHT): Several ongoing clinical trials are aimed at comparing the effects of calcium antagonists and ACE inhibitors versus beta-blockers and diuretics on cardiovascular morbidity and mortality. INSIGHT is particularly interesting because the effects of nifedipine GITS and a combined thiazide and potassium-sparing diuretic on cardiovascular morbidity and fatal events are being compared in patients with hypertension plus one or more additional risk factors, such as hypercholesterolemia, smoking, diabetes, left ventricular hypertrophy, etc. INSIGHT is therefore the first trial to address, in a prospective fashion, the prognostic influence of antihypertensive treatment in hypertensives with concomitant risk factors.

Calcium Channel Blockers↗
PubMed1996

Heart rate-dependence of arterial distensibility in vivo.

OBJECTIVES: Viscous and inertial components contribute to arterial distensibility and compliance in vitro. The purpose of our study was to determine whether this phenomenon is of relevance in vivo, namely, whether arterial compliance is altered by an increase in heart rate. DESIGN: Arterial diameter was assessed by an echo-Doppler device in a common carotid and femoral artery, namely, in a large elastic and a muscle artery. The studies were performed in 12-week-old pentobarbitone-anaesthetized Wistar-Kyoto rats subjected to atrial pacing via a transjugular unipolar catheter at five different randomly sequenced rates (280, 310, 340, 370 and 400 beats/min). After each stage, spontaneous sinus rhythm was allowed to return. Blood pressure was measured via a catheter inserted into the carotid or femoral artery contralateral to the vessels in which the diameter was measured. Arterial compliance and distensibility values were derived according to the Langewouters formula. RESULTS: A progressive increase in heart rate caused by pacing was accompanied by progressive and marked reductions in carotid artery compliance and distensibility. When quantified by the area under the distensibility-pressure or compliance-pressure curve the reduction was in the range 15-43%. Although a tendency to a similar phenomenon was observed in the femoral artery, in the latter vessel the reduction in distensibility and compliance was less marked and statistically insignificant. CONCLUSIONS: In the anaesthetized rat acute increases in heart rate are accompanied by reductions in arterial compliance and distensibility. The effect is greater in elastic than in muscle arteries.

Animals↗
PubMed1996

Ambulatory blood pressure monitoring.

PREDICTIVE VALUE OF 24-H AMBULATORY BLOOD PRESSURE MONITORING: Average 24-h blood pressure values are more closely related to the target-organ damage of hypertension than are clinic blood pressure readings. Preliminary evidence from longitudinal studies suggests that ambulatory blood pressure is also superior to isolated clinic readings in the prognostic evaluation of hypertensive patients. This is supported by the demonstration that in hypertensive patients with left ventricular hypertrophy, regression of cardiac hypertrophy following treatment was better predicted by the drug-induced reduction in 24-h average blood pressure than clinic blood pressure. BLOOD PRESSURE VARIABILITY: Also, 24-h blood pressure variability seems to be involved in the genesis of hypertension target-organ damage, while the clinical value of specific components of the 24-h blood pressure profile, such the nocturnal blood pressure fall, is still a matter of debate. Similar caution is needed in approaching the clinical significance of white coat hypertension, the definition of which is still affected by important methodological problems.

Blood Pressure↗
PubMed1996

Considerations on current and future trials in hypertension.

Conclusive evidence from large-scale epidemiological studies has shown that hypertension is a major risk factor for cardiovascular disease. Large-scale intervention trials have indicated that, by reducing elevated blood pressure values with antihypertensive treatment, the risk can be decreased. Despite the large body of evidence on the protective effects of the blood pressure reduction, several questions concerning the benefit of antihypertensive treatment remain unanswered. This paper briefly reviews the information provided by clinical trials on antihypertensive treatment. It also critically examines the questions that have remained partially or totally unanswered and the trials that are currently addressing them. Focus is directed on the Insight Study which addresses the benefit of antihypertensive treatment in hypertensive subjects with additional cardiovascular risk factors.

Antihypertensive Agents↗
PubMed1996

Job strain and ambulatory blood pressure levels in a population-based employed sample of men from northern Italy.

OBJECTIVES: The purpose of this cross-sectional study was to examine the associations between categories of perceived job strain and blood pressure, measured by clinical and ambulatory devices on a population-based sample of employed men in northern Italy. METHODS: The study included 527 employed normotensive or mild hypertensive nonmedicated men enrolled in an age-gender stratified random sample of 821 25- to 64-year-old residents of the city of Monza (in the vicinity of Milan). The job-strain categories were classified according to the traditional quadrant-term approach and also a new approach based on the comparison of extreme tertile categories in order to enhance contrasts. Clinical blood pressure was measured according to the standardized MONICA procedure; 24-h, work, leisure, and nighttime blood pressure values were obtained with an ambulatory device. Disparities, calculated as differences between clinical and ambulatory measurements, were also analyzed. RESULTS: Among normotensive working men the highest mean for systolic blood pressure was found in the high-strain group, and progressively lower values were found in the passive, active and low-strain categories. These patterns were observed for both the clinical and ambulatory measurements. Among the mild hypertensive subjects, lower mean values for ambulatory systolic and diastolic blood pressure were found in the passive and high job-strain categories when the tertile term approach was adopted. The passive group also showed the highest mean difference between the clinical and ambulatory measurements; this finding indicates that they may be more susceptible to alarm reactions. CONCLUSIONS: The results indicate that job strain affects blood pressure in population-based samples and the effect is consistent across sociocultural contexts.

Adult↗
PubMed1996

Conventional and ambulatory blood pressure measurement in older patients with isolated systolic hypertension:second progress report on the ambulatory blood pressure monitoring project in the Syst-Eur trial.

OBJECTIVES: To compare clinic and ambulatory blood pressure measurement and the reproducibility of these measurements in older patients with isolated systolic hypertension.PATIENTS: A total of 477 patients aged >/= 60 years with isolated systolic hypertension on clinic measurement were monitored during the placebo run-in phase of the Syst-Eur trial. METHODS: The time-weighted 24 h blood pressure, clock time day and night blood pressure, the cumulative sum-derived crest and trough blood pressure and the high and low blood pressure levels of the square-wave model were computed. The daily alteration between the high and low blood pressure spans was quantified using the clock time day-night difference, the cumulative sum-derived circadian alteration magnitude, the Fourier amplitude and the difference between the high and low blood pressure levels of the square-wave model. RESULTS: The daytime ambulatory systolic blood pressure was, on average, 21 mmHg lower than the clinic blood pressure, whereasthe diastolic blood pressure was, on average, similar with both techniques of measurement. In the 132 patients who underwent repeat measurements, clinic blood pressure levels and the parameters describing the difference betgween the daily high and low blood pressure spans were equally reproducible. However, both were less reproducible than the ambulatory blood pressure levels. The repeatability coefficients, expressed as percentages of near maximum variation, were 50 and 51% for the clinic systolic and diastolic blood pressures, 30 and 33% for the mean 24 h systolic and diastolic blood pressures and between 44 and 54% for the parameters describing the daily alteration between the high and low blood pressure spans. CONCLUSION: In older patients with isolated systolic hypertension, clinic and ambulatory systolic blood pressure may differ greatly; the prognostic significance of this difference remains to be elucidated. Furthermore, the level of blood pressure in these patients is more reproducible by ambulatory measurement than it is by clinic measurement.

Journal Article↗
PubMed1996

Reproducibility of blood pressure measurements.

Clinic blood pressure readings are less reproducible than 24 h and daytime average ambulatory blood pressures. This may depend on (1) the continuous and spontaneous variability which characterizes daily life blood pressure, (2) the well-known 'white-coat' effect and (3) other methodological problems affecting traditional sphygmomanometric readings, such as the observer's bias and digit preference. The higher reproducibility of average 24 h and daytime blood pressures is also, at least in part, a function of the greater number of blood pressure readings available. On the other hand, the various components of the 24 h blood pressure profile appear, in general, to be less reproducible than the 24 h average value. This is the case for hourly values, for the day-night blood pressure difference and for a number of statistical parameters employed for modelling the 24 h blood pressure curve. An alternative and simple way to obtain reproducible blood pressure values, without making use of ambulatory blood pressure monitoring techniques, may be offered by the average of 20-25 blood pressure readings obtained automatically or semi-automatically under standardized conditions in outpatient clinics. The implications of these findings for clinical trials aimed at evaluating the features of the effects of antihypertensive drugs on 24 h blood pressure are discussed.

Journal Article↗
PubMed1996

Lack of effect of percutaneous transluminal renal angioplasty on nocturnal hypotension in renovascular hypertensive patients.

OBJECTIVE: To investigate whether nocturnal blood pressure fall is blunted in renovascular hypertension and can therefore be used as a diagnostic criterion for this condition. METHODS: In 14 renovascular hypertensive patients (age 43.8+/-2.1 years, mean+/-SEM, clinic blood pressure 173.6+/-3.7 mmHg systolic and 109.0+/-2.0 mmHg diastolic) and in 14 age- and blood pressure-matched essential hypertensive controls 24 h ambulatory blood pressure was measured after washout from drug treatment, during angiotensin converting enzyme inhibitor treatment and, in renovascular hypertension, also after percutaneous transluminal renal angioplasty. RESULTS: The 24 h average systolic and diastolic blood pressures were 146.4+/-5.7 and 97.5+/-3.6 mmHg in renovascular and 144.3+/-1.2 and 98.0+/-2.2 mmHg in essential hypertensive patients. The angiotensin converting enzyme inhibitor treatment reduced 24 h average systolic and diastolic blood pressures by 8.5% and 9.7% in the renovascular and by 8.3% and 10.8% in the essential hypertensive group. Greater systolic and diastolic blood pressure reductions (-18.2% and -18.1%) were observed in renovascular hypertensive patients after percutaneous transluminal renal angioplasty. Blood pressure fell by about 10% during the night and the fall was similar in renovascular and in essential hypertensive patients. In the former group, nocturnal hypotension was similar after washout, during angiotensin converting enzyme inhibitor treatment and after percutaneous transluminal renal angioplasty. Similar results were obtained for nocturnal bradycardia. CONCLUSIONS: Nocturnal blood pressure fall is equally manifest in renovascular and essential hypertension. The removal of the renal artery stenosis and blood pressure normalization do not enhance this phenomenon. Nocturnal hypotension seems therefore to be unaffected by renovascular hypertension.

Adult↗
PubMed1996

Lessons to be learned from 24-hour ambulatory blood pressure monitoring.

A number of cross sectional studies have shown that both the 24-hour average blood pressure value and the degree of 24-hour blood pressure variability bear a significant relation with the end organ damage of hypertension. Although longitudinal evidence of the clinical relevance of 24-hour ambulatory blood pressure monitoring data are scanty, the results of a recent prospective study have clearly shown the superiority of average 24 hour, daytime and nighttime blood pressure values over clinical readings in predicting the regression of left ventricular hypertrophy in treated hypertensive patients. Ambulatory blood pressure monitoring may also be useful in the evaluation of antihypertensive treatment, although the problem of whether ambulatory blood pressure is "normalized" by treatment remains still to be properly addressed. Moreover, currently employed discontinuous ambulatory blood pressure monitoring devices cannot adequately clarify the ability of antihypertensive drugs to buffer blood pressure variability. This interesting issue needs to be assessed in a more analytical fashion by means of recently developed beat-to-beat non-invasive ambulatory blood pressure recorders coupled with wide-band spectral analysis techniques.

Animals↗
PubMed1996

Baroreflex modulation of the cardiovascular system: new insights from the joint analysis of blood pressure and heart rate signals.

This paper focuses on a number of methods for the analysis of the relationship between the arterial baroreflex and different components of blood pressure and heart rate variability. Broad-band spectral analysis techniques have allowed us to obtain experimental evidence that the arterial baroreflex exerts its influence not only on fast but also on slow components of blood pressure and heart rate, i.e., on components with periods longer than 60 sec. Focusing on faster changes in blood pressure and heart rate, both time domain and frequency domain techniques have been developed to track the sensitivity of baroreflex heart rate modulation over time, either in laboratory or in daily life conditions. These approaches have considerably broadened our understanding of the role of baroreflex modulation of the heart and peripheral circulation in a number of pathological and physiological conditions.

Animals↗