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Gianfranco Parati

Publications and source records attributed to Gianfranco Parati.

At least 91 records · Page 5Linked to original sources
PubMed2003

Non-invasive beat-to-beat blood pressure monitoring: new developments.

Continuous blood pressure monitoring is an essential prerequisite for any study on blood pressure variability. Invasive procedures are no longer acceptable for research projects in a clinical setting, and recently developed devices able to record blood pressure on a beat-by-beat basis in a non-invasive fashion may represent valuable alternative tools. This article will briefly review the available information on the most recent advances in this field. It will focus on further developments of the original technology for finger blood pressure monitoring introduced by Penáz, as well as on newer devices that have been proposed over the last few years for non-invasive cardiovascular monitoring both in research and in clinical studies.

Blood Pressure Determination↗
PubMed2003

Assessment of overall blood pressure variability and its different components.

Blood pressure (BP) is characterized by continuous fluctuations, including fast changes lasting only a few seconds as well as slower and more prolonged variations, with a time constant of minutes or hours. Assessing the relative contribution of these different components to overall blood pressure variance is now possible through a number of mathematical approaches, either in the time or in the frequency domain (spectral analysis). Due to its complex nature, a precise and detailed assessment of blood pressure variability can be obtained only from the analysis of continuous, beat-by-beat, blood pressure recordings. Some information, however, can also be derived from analysis of discontinuous blood pressure tracings, such as those commonly performed in a clinical setting. This would require that attention is paid both to the quality of the recordings and to the selection of suitable analysis methods that should cope with the discontinuous nature of the measurements to be processed and to their intrinsic low sampling frequency.

Blood Pressure↗
PubMed2003

Renal and cardiovascular responses to water immersion in essential hypertension: is there a role for the opioidergic system?

Our study aimed at elucidating the effects of acute central hypervolemia induced by water immersion (WI) on renal hemodynamics, hormonal responses and on cardiovascular control in hypertensive patients, as well as at evaluating the possible role of the opioidergic system (OS) in determining these effects. Thirteen essential hypertensives were studied for 2 h before and for 2 h during WI. This was done twice, without and with i.v. injection of the OS antagonist naloxone. Before and during WI alone, glomerular filtration rate (GFR), effective renal plasma flow (ERPF), renal vascular resistance (RVR), mean arterial pressure (MAP), pulse interval (PI), spontaneous baroreflex sensitivity (BRS), Low frequency to High frequency (LF/HF) ratio in PI spectra, hematocrit, urinary sodium excretion, plasma renin activity (PRA) and aldosterone (PA) were assessed. Based on their response to WI, hypertensives were subdivided into two groups: ERPF+ (n = 7) in whom WI increased ERPF, and ERPF- (n = 6) in whom WI reduced ERPF. ERPF+ displayed a higher BRS than ERPF- at baseline and during WI. A suppression of PRA and PA and an increase in MAP and urinary sodium excretion were found in both groups. In ERPF+ naloxone caused RVR and MAP to increase during WI and this response was associated with a blockade of the increase in ERPF in this group, while BRS and natriuresis were unchanged. In ERPF- naloxone did not affect WI-induced MAP, ERPF, RVR and BRS changes, while it blunted sodium excretion. Our data provide the first evidence of a differentiate renal hemodynamic response to WI in hypertension; they also suggest that while OS may significantly potentiate the renal vasodilatory response to WI in ERPF+, it does not affect the natriuretic response nor the changes in systemic cardiovascular regulation induced by central hypervolemia.

Adult↗
PubMed2002

Predictive value of clinic and ambulatory heart rate for mortality in elderly subjects with systolic hypertension.

OBJECTIVE: To examine the association of clinic and ambulatory heart rate with total, cardiovascular, and noncardiovascular death in a cohort of elderly subjects with isolated systolic hypertension from the Systolic Hypertension in Europe Trial. METHODS: A total of 4682 patients participated, whose untreated blood pressure on conventional measurement at baseline was 160 to 219 mm Hg systolic and lower than 95 mm Hg diastolic. Clinic heart rate was the mean of 6 readings during 3 visits. Ambulatory heart rate was recorded with a portable intermittent technique in 807 subjects. RESULTS: Raised baseline clinic heart rate was positively associated with a worse prognosis for total, cardiovascular, and noncardiovascular mortality among the 2293 men and women taking placebo. Subjects with heart rates higher than 79 beats/min (bpm) (top quintile) had a 1.89 times greater risk of mortality than subjects with heart rate lower than or equal to 79 bpm (95% confidence interval, 1.33-2.68 bpm). In a Cox regression analysis, predictors of time to death were heart rate (P<.001), age (P<.001), serum creatinine level (P =.001), presence of diabetes (P =.002), previous cardiovascular disease (P =.01), triglyceride readings (P =.02), smoking (P =.04), and elevated systolic blood pressure (P =.05), while total cholesterol level was found to be nonsignificant in the model. In the ambulatory monitoring subgroup, clinic and ambulatory heart rates predicted noncardiovascular but not cardiovascular mortality. However, in a Cox regression analysis in which clinic and ambulatory heart rates were included, a significant association with noncardiovascular mortality was found only for clinic heart rate (P =.004). In the active treatment group, the weak predictive power of clinic heart rate for mortality disappeared after adjustment for confounders. CONCLUSIONS: In untreated older patients with isolated systolic hypertension, a clinic heart rate greater than 79 bpm was a significant predictor of all-cause, cardiovascular, and noncardiovascular mortality. Ambulatory heart rate did not add prognostic information to that provided by clinic heart rate.

Age Factors↗
PubMed2002

Continuous positive airway pressure treatment improves baroreflex control of heart rate during sleep in severe obstructive sleep apnea syndrome.

The role of the arterial baroreflex in the cardiovascular changes associated with the obstructive sleep apnea syndrome (OSAS), and the effect of nasal continuous positive airway pressure (CPAP) treatment on baroreflex function during sleep are unknown. Baroreflex control of heart rate was studied in 29 normotensive patients with OSAS under no treatment, in 11 age-matched control subjects, and in 10 patients at CPAP withdrawal after 5.5 +/- 3.7 (range 3-14) months of treatment. Baroreflex control of heart rate was assessed by "sequence method" analysis of continuous blood pressure recordings (Finapres) obtained during nocturnal polysomnography. In untreated OSAS, baroreflex sensitivity (BRS) was low during wakefulness and non-rapid eye movement (REM) stage 2 sleep compared with control subjects, and correlated inversely with mean lowest Sa(O(2)) and the blood pressure increase after apneas. After CPAP treatment, the apnea-hypopnea index was lower, and mean lowest Sa(O(2)) higher than before treatment. After CPAP, patients were more bradycardic, blood pressure and its standard deviation decreased as Sa(O(2)) improved in non-REM stage 2 sleep, and BRS increased (nocturnal wakefulness: +59%; non-REM stage 2 sleep: +68% over pretreatment values). Our data suggest that baroreflex dysfunction in OSAS may be at least partly accounted for by nocturnal intermittent hypoxemia, and can be reversed by long-term CPAP treatment.

Adult↗
PubMed2002

Ambulatory pulse pressure as predictor of outcome in older patients with systolic hypertension.

We enrolled 808 older patients with isolated systolic hypertension (160 to 219/71 <95 mm Hg) to investigate whether ambulatory measurement of pulse pressure and mean pressure can refine risk stratification. The patients (> or =60 years) were randomized to nitrendipine (10 to 40 mg/day) with the possible addition of enalapril (5 to 20 mg/day) or hydrochlorothiazide (12.5 to 25 mg/day) or to matching placebos. At baseline, pulse pressure and mean pressure were determined from six conventional blood pressure (BP) readings and from 24-h ambulatory recordings. With adjustment for significant covariables, we computed mutually adjusted relative hazard rates associated with 10 mm Hg increases in pulse pressure or mean pressure. In the placebo group, the 24-h and nighttime pulse pressures consistently predicted total and cardiovascular mortality, all cardiovascular events, stroke, and cardiac events. Daytime pulse pressure predicted cardiovascular mortality, all cardiovascular end points, and stroke. The hazard rates for 10 mm Hg increases in pulse pressure ranged from 1.25 to 1.68. Conventionally measured pulse pressure predicted only cardiovascular mortality with a hazard rate of 1.35. In the active treatment group compared with the placebo patients, the relation between outcome and ambulatory pulse pressure was attenuated to a nonsignificant level. Mean pressure determined from ambulatory or conventional BP measurements was not associated with poorer prognosis. In conclusion, in older patients with isolated systolic hypertension higher pulse pressure estimated by 24-h ambulatory monitoring was a better predictor of adverse outcomes than conventional pulse pressure, whereas conventional and ambulatory mean pressures were not correlated with a worse outcome.

Aged↗
PubMed2002

Twenty-four hour ambulatory blood pressure in the International Nifedipine GITS Study Intervention as a Goal in Hypertension Treatment (INSIGHT).

OBJECTIVES: The International Nifedipine GITS Study Intervention as a Goal in Hypertension Treatment (INSIGHT) showed, by means of office blood pressure measurements, that long-term treatment with nifedipine GITS is as effective as diuretics in preventing cardiovascular and cerebrovascular complications. However, since office blood pressure measurements reflect to a limited extent blood pressure outside the office, a side-arm INSIGHT study in which patients underwent both office measurement and 24 h ambulatory blood pressure monitoring was also performed. DESIGN AND METHODS: The study had a randomized, double-blind, parallel group design. After 4 weeks of placebo, mild-to-moderate essential hypertensive patients were randomized to nifedipine GITS 30 mg or amiloride 2.5 + hydrochlorothiazide 5 mg for 3.1 years. Dose titration was performed by dose doubling and addition of atenolol 25-50 mg or enalapril 5-10 mg, or other drugs when needed. Analysis was carried out by intention-to-treat and included computation of 24 h, day and night ambulatory blood pressure and heart rate values. Additional analyses included computation of the trough-to-peak ratio and the smoothness index (the ratio between the average of the 24-hourly blood pressure reductions after treatment and its standard deviation). RESULTS: A total of 151 patients were recruited and 149 were valid for analysis: 78 patients had 24 h ambulatory recordings both at baseline and during treatment and 134 during treatment. Office, 24 h and day and night blood pressures were all significantly and similarly reduced by both treatments. Office and ambulatory heart rate was left unchanged by diuretics, while it was slightly reduced by nifedipine. Median trough-to-peak ratios were always > 0.5 and superimposable between the two treatment groups. Similarly, smoothness indices of systolic and diastolic blood pressures were comparably high for nifedipine and diuretics, thus demonstrating a similar well-balanced antihypertensive response to both drugs. No significant differences were observed between the two treatment groups in the number of cardiovascular events (17 in the nifedipine-based and 26 in the diuretics-based treatment group). CONCLUSIONS: In the INSIGHT study, the long-term antihypertensive effect on 24 h blood pressure and the cardiovascular protection of nifedipine was similar to that of diuretics.

Aged↗
PubMed2002

Variable day/night bias in 24-h non-invasive finger pressure against intrabrachial artery pressure is removed by waveform filtering and level correction.

BACKGROUND Twenty-four-hour finger arterial pressure (FAP) recordings show a negative bias against intrabrachial artery pressure (BAP) and the bias is greater during the night, thereby overestimating the nocturnal blood pressure dip. We have available a methodology with which to reconstruct BAP from FAP by waveform filtering (transfer function) and generalized level (bias) correction that reduces the bias for short-term blood pressure records. OBJECTIVE To investigate if this methodology also decreases the extra bias during the night, thereby yielding a better estimate of the nocturnal dip. METHODS Twenty-four-hour FAP and BAP blood pressure recordings were simultaneously obtained in eight healthy normotensive volunteers and 14 patients with hypertension (ages 19-60 years), during standardized scheduled activities. The data were analysed off-line, applying the brachial reconstruction technique (reBAP) consisting of a waveform filter and level correction. Simultaneous beats yielded systolic, diastolic and mean pressures that were averaged per 30 min, per day, per night, per activity, over the 24-h period, and for volunteers and patients separately. RESULTS Over the full 24 h, FAP systolic, diastolic and mean values for the total group differed from BAP by +1 +/- 10, -8 +/- 7 and -10 +/- 8 mmHg (mean +/- SD), respectively. Similarly, reBAPs differed by +1 +/- 11, -2 +/- 7 and -2 +/- 7 mmHg. BAPs dipped by 20 +/- 8, 13 +/- 6 and 15 +/- 6 mmHg, respectively, during the night. These dips were overestimated by +8, +4 and +4 mmHg by FAP, but not by reBAP: -1, +1 and +1 mmHg. The volunteer and the patient groups showed slight differences in results, but these were not statistically significant. CONCLUSIONS The generalized reconstruction technique to obtain near-brachial pressure from non-invasive FAP almost completely removed bias over the full 24-h day-night period and improved tracking of diurnal changes for all three blood pressure values.

Adult↗
PubMed2002

Sleep apnoea and hypertension.

This review article provides an update on two major issues. First, the most recent evidence supporting the occurrence of an association between obstructive sleep apnoea syndrome, or more generally sleep-disordered breathing, and arterial hypertension in humans is summarized and discussed. This includes an evaluation of both cross-sectional and longitudinal studies. Second, new insights into the mechanisms responsible for the appearance of chronic hypertension in individuals suffering from recurrent nocturnal apnoeic episodes are provided, based both on experimental studies in animals and on clinical studies in humans. The relevance of these data for the clinical management of hypertensive patients with sleep-disordered breathing, and the possibility of obtaining a reduction in blood pressure through the application of nasal continuous positive air pressure, is also addressed.

Animals↗
PubMed2002

Blood pressure measurement in research.

OBJECTIVE: The aim of this paper is to summarize the issues raised during a consensus conference on the role of different blood pressure (BP) monitoring techniques in research, including pathophysiological studies, clinical outcome trials and clinical pharmacology trials. METHODS: This review includes the contribution of the participants in a task force at the Eighth Consensus Conference on Ambulatory BP Monitoring (October 28-31, 2001, Sendai, Japan) and the results of a discussion open to all conference participants. Individual contributions have been summarized together with the points raised during the subsequent discussion, and the main statements are also presented in a table format. POINTS OF CONSENSUS: (1) BP monitoring in pathophysiological studies. The essential role played by continuous BP monitoring in this field had been acknowledged, and further development of non-invasive beat-by-beat monitoring techniques has been advocated. (2) BP monitoring in clinical trials. In clinical trials automated ambulatory BP monitoring (ABPM) and self BP measurements (SBPM) at home share similar advantages, with specific features that make these approaches not alternative solutions but rather approaches able to complement each other. A few examples of application of ABPM and SBPM in clinical trials include the Treatment of Hypertension according to Home or Office Blood Pressure (THOP) trial and the Trial of Preventing Hypertension (TROPHY). (3) Use of ABPM in clinical pharmacology studies. Use of ABPM is now an established routine, aimed at describing the 24-h effect of new antihypertensive drugs. An example of these applications that was discussed in the conference is the use of ABPM in the evaluation of a new long-acting calcium channel blocker (Barnidipine) (J-MUBA study). (4) Specific models for the analysis of BP fluctuations. The features characterizing the chronobiological approach to description of 24-h BP profiles and its limitations (mainly consisting of the high risk of data over-modelling) are discussed. Also the possible occurrence of a circaseptan (approximately with a 7-day period) rhythm in BP has been addressed, although repeated performance of 24-h ABPM over a week obviously faces a number of practical problems. (5) Progress in technology: BP monitoring and telemedicine. The possibility to implement an interactive telemonitoring system of home SBPM values and the perspectives for a clinical application of this technology in the Hypertension Objective treatment based on Measurement by Electrical Devices of Blood Pressure (HOMED-BP) trial is discussed.

Biomedical Research↗