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Biomedical subjects

G Mancia

Publications and source records attributed to G Mancia.

At least 307 records · Page 17Linked to original sources
PubMed1993

Relationship between blood pressure measured in the clinic and by ambulatory monitoring and left ventricular size as measured by electrocardiogram in elderly patients with isolated systolic hypertension.

OBJECTIVE: To assess the additional diagnostic precision conferred by ambulatory blood pressure monitoring on clinic blood pressure measurement in evaluating the severity of isolated systolic hypertension. METHODS: The association between left ventricular size as determined by ECG voltages [R-wave voltages in lead V5 (RV5) and S-wave voltages in lead V1 (SV1)] and blood pressure as assessed by clinic measurements and ambulatory blood pressure monitoring was studied in 97 elderly patients included in the placebo run-in phase of the Syst-Eur trial. The additional diagnostic precision conferred by ambulatory monitoring on clinic blood pressure measurements was assessed by relating the residual ambulatory blood pressure level to the ECG-left ventricular size. The residual ambulatory blood pressure level was calculated by subtracting the predicted ambulatory blood pressure level for each patient (using the linear regression equation relating both techniques for the group) from the observed ambulatory blood pressure. RESULTS: Clinic systolic blood pressure was on average 20 mmHg higher (P < 0.001) than daytime ambulatory blood pressure while diastolic blood pressure was similar with both techniques. The sum of SV1 + RV5 was significantly related to clinic systolic pressure (r = 0.25), and 24-h (systolic, r = 0.37; diastolic, r = 0.29), daytime (systolic, r = 0.30; diastolic, r = 0.19) and night-time (systolic, r = 0.33; diastolic, r = 0.28) ambulatory blood pressure levels. These findings were not affected by adjustment for gender, age and the body mass index. The sum of SV1 + RV5 was significantly related to the residual 24-h (systolic, r = 0.30; diastolic, r = 0.31), daytime systolic (r = 0.20) and night-time (systolic, r = 0.31; diastolic, r = 0.29) ambulatory blood pressure monitoring levels. CONCLUSION: Ambulatory blood pressure monitoring adds to the diagnostic precision of clinic blood pressure measurement in assessing the severity of hypertension in this population. The ongoing side project on ambulatory blood pressure monitoring in the Syst-Eur study should establish whether these findings hold true for morbidity and mortality.

Aged↗
PubMed1993

Vascular effects of lacidipine: a review of animal and human data.

AIM: To compare the vascular effects of lacidipine with those of other calcium antagonists. METHODS: A review of published studies. RESULTS: Experimental studies have shown that for a similar fall in blood pressure, lacidipine increased cardiac contractility while verapamil decreased cardiac contractility. In the rat aorta, the dose of lacidipine required to reduce a calcium-induced contraction by 50% was lower than that of all other calcium antagonists tested except nisoldipine. In human studies, especially, there are inherent limitations in the techniques available to measure regional blood flows under physiological conditions, making it difficult to compare the effects of different antihypertensive drugs. A recent study showed that renal blood flow was increased by lacidipine without any reduction in renal function. As in animals, vital organ perfusion was either preserved or increased. Further, maximal coronary vasodilation was associated with lower coronary resistance values during lacidipine treatment compared with pretreatment values. Another lacidipine study showed increased brachial artery compliance, while a study on the radial artery showed that lacidipine increased the compliance of this artery also. CONCLUSIONS: Lacidipine has vascular selectivity. Although regional blood flows are difficult to measure, due to inherent limitations in the techniques available, the evidence suggests that lacidipine produces vasodilation in essential hypertensive subjects while maintaining or even increasing vital organ perfusion. This appears to be due to a regression of the structural changes that characterize hypertension.

Animals↗
PubMed1993

Spontaneous variability of regional haemodynamics in unanaesthetized rats.

AIM: To study the spontaneous variability in regional haemodynamics. METHODS: Twenty normotensive Wistar-Kyoto rats were chronically instrumented with an arterial catheter and with pulsed Doppler flowmeters on the distal aorta, and the superior mesenteric and left renal arteries. After surgical recovery, the rats were monitored in unrestrained conditions. The recorded signals were analysed beat-to-beat to obtain means and coefficients of variation for mean arterial pressure, heart rate, regional blood flow velocity (consecutive 0.8-s periods) and indices of regional vascular resistance (0.8-s ratio of mean arterial pressure to mean blood flow velocity). RESULTS: Muscle and splanchnic blood flow velocities were markedly variable, with coefficients of variation of 12.8 +/- 0.8 and 12.2 +/- 1.7% (means +/- SEM), respectively, about twice as large as the coefficient of variation for mean arterial pressure (6.2 +/- 0.3%). The renal blood flow velocity was slightly less variable than the muscle and splanchnic blood flow velocities, with a coefficient of variation of 10.4 +/- 0.8%, but still markedly and significantly more variable than systemic arterial pressure. A contingency analysis of paired variations in any two given parameters (arterial blood pressure, heart rate, blood flow velocities and indices of vascular resistance) showed a concordant pattern, the only exception being a distinctly discordant trend for the covariations in muscle and splanchnic blood flow velocities. CONCLUSIONS: Regional blood flow velocity and vascular resistance have a larger degree of spontaneous variability than systemic arterial pressure. Renal blood flow velocity is also highly variable, suggesting that short-term stimuli that affect the renal blood vessels are not countered by autoregulation to any great degree. We conclude that while central factors may drive concordant regional haemodynamic variations, some opposing changes in regional blood flow velocity may cancel each other out, thereby reducing the variability in systemic blood pressure.

Animals↗
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↗
PubMed1993

Feasibility of ambulatory, continuous 24-hour finger arterial pressure recording.

We tested Portapres, an innovative portable, battery-operated device for the continuous, noninvasive, 24-hour ambulatory measurement of blood pressure in the finger. Portapres is based on Finapres, a stationary device for the measurement of finger arterial pressure. Systems were added to record signals on tape, to alternate measurements between fingers automatically each 30 minutes, and to correct for the hydrostatic height of the hand. We compared the pressure as measured by Portapres with contralateral intrabrachial pressure measured with an Oxford device. Results were obtained in eight volunteers and 16 hypertensive patients. Time lost due to artifact was about 10% for each device. In two patients a full 24-hour Oxford profile was not obtained. In the remaining 22 subjects finger systolic, diastolic, and mean pressures differed +1 (SD 9), -8 (6), and -10 (6) mm Hg, respectively, from intrabrachial pressure. These diastolic and mean pressure underestimations are similar to what was found earlier for Finapres, are typical for the technique, and are systematic. Avoiding brisk hand movements resulted in fewer waveform artifacts. The hand had to be kept covered to continue recording at low outside temperatures. Sleep was not disturbed by Portapres, and arterial pressure showed a marked fall during siesta and nighttime. There were no major limitations in behavior, and no discomfort that originated from continuous monitoring was reported. Measurements continued normally during physical exercise. Portapres provides for the first time continuous 24-hour, noninvasive ambulatory blood pressure waveform monitoring and offers real and obvious advantages over current noninvasive and invasive devices.

Adult↗
PubMed1993

Spectral and sequence analysis of finger blood pressure variability. Comparison with analysis of intra-arterial recordings.

The aim of our study was to assess whether the Finapres device is able to accurately monitor not only average blood pressure values but also blood pressure variability. To examine this issue, we analyzed 30-minute recordings of finger and intra-arterial pressure simultaneously obtained at rest in 14 patients. We compared systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse interval (the reciprocal of heart rate), overall variability (standard deviation), and specific time-domain and frequency-domain components. Systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse interval spectral powers were computed by fast Fourier transform over three frequency bands: low frequency (0.025 to 0.07 Hz), midfrequency (0.07 to 0.14 Hz), and high frequency (0.14 to 0.35 Hz). The coherence, ie, the degree of association between blood pressure and pulse interval powers obtained by the two techniques, was also assessed. Standard deviations of diastolic blood pressure, mean arterial pressure, and pulse interval were similar when assessed from the two recordings, whereas standard deviation of systolic blood pressure was overestimated by analysis of finger pressure recordings. All powers of diastolic blood pressure and mean arterial pressure and high-frequency powers of systolic blood pressure estimated from analysis of finger blood pressure tracings were superimposable to those obtained by analyzing invasive recordings. Low-frequency and midfrequency powers of intra-arterial systolic blood pressure were significantly overestimated by the analysis of finger blood pressure tracings (+13.7 +/- 4.4 mm Hg2, P < .01, and +2.3 +/- 0.9 mm Hg2, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

New aspects of antihypertensive treatment. Metabolism, the kidney and the heart.

This paper briefly reviews recent evidence concerning the relationship between hypertension and alterations in glucose and lipid metabolism and renal and cardiac damage. It is now clear that high blood pressure is frequently associated with insulin resistance and dyslipidaemia. This suggests a possible pathogenetic link between hypertension and deranged metabolism. It also suggests, however, that the hypertensive patient is likely to have other cardiovascular risk factors in addition to hypertension. It is also clear that lowering blood pressure may not only reduce the overall cardiovascular risk but may be specifically nephro- and cardioprotective. However, it is difficult to assess the effect of antihypertensive treatment in these areas, because there are no simple and sensitive measures of the progression of renal disease, and antihypertensive therapy does not provide consistent protection against coronary heart disease. Furthermore, the degree of protection obtained is less than would be expected on the basis of epidemiological evidence. Further trials are needed to fully resolve these issues.

Animals↗
PubMed1993

Vasovagal syncope with bradycardia during lower body negative pressure in a heart transplant recipient.

Vasovagal syncope has been ascribed to the vagal excitation and the sympathetic inhibition induced reflexly by mechanical stimulation of receptors in the ventricles. In this case report we describe a vasovagal syncope with bradycardia triggered by a reduction in venous return obtained via mild lower body negative pressure, in a patient with cardiac denervation due to heart transplantation. This suggests that the mechanisms involved in this phenomenon may not exclusively depend on a reflex originating from ventricular receptors. It also suggests that non-neural factors may be involved in the genesis of the bradycardia.

Blood Pressure↗
PubMed1993

Ambulatory blood pressure monitoring in hypertension.

Ambulatory blood pressure monitoring generates a greater interest among investigators and clinicians because of its potential to 1) study the mechanisms involved in cardiovascular control in daily life (particularly if monitoring is performed on a beat-to-beat basis) and 2) improve the diagnosis of hypertension, the estimate of the patient's risk and the assessment of the efficacy of antihypertensive treatment. This paper will discuss the evidence pros and cons the latter indications of this approach. It will be shown that 24 hour blood pressure values correlate more closely than clinic blood pressure with various measures of the end organ damage of hypertension, suggesting that it may reflect better than traditional blood pressure measurements the cardiovascular consequences of this condition. Wider use of ambulatory blood pressure monitoring in the medical practice, however, must await a more clear demonstration of its prognostic importance, by longitudinal studies based on cardiovascular morbidity and mortality or on surrogate end points with undisputable clinical significance (e.g. left ventricular hypertrophy). It must also await clear definition of ambulatory blood pressure normality based on population studies. Until then ambulatory blood pressure monitoring should be employed to resolve special problems, e.g. identification of white coat hypertension and false non response to treatment.

Ambulatory Care↗
PubMed1993

[Arterial hypertension and myocardial infarction].

Several epidemiological and clinical studies, carried over the past 30 years, have unequivocally shown that high blood pressure is an important risk factor for development of myocardial infarction. The risk level, which has been documented for an increase both in systolic and diastolic blood pressure values, further increases when hypertension is accompanied with other conditions (e.g. hyperlipidemia, diabetes, cigarette smoking) well-known to adversely affect the cardiovascular system. Antihypertensive treatment significantly decreases, although without normalizing, the incidence of coronary events in the hypertensive patient, the reasons for this only partial cardioprotection being so far largely unknown. More complex and less documented are the relationships between hypertension and myocardial reinfarction. Although there is no doubt that high blood pressure levels increase the incidence of reinfarction, it should be emphasized that no study so far has been undertaken to clarify the effectiveness of antihypertensive treatment in reducing the risk of myocardial infarction and in improving the prognosis of the disease.

Humans↗
PubMed1993

[Hypertension, left ventricular hypertrophy and heart failure].

Epidemiological and clinical studies carried out over the past 30 years have unequivocally shown that cardiac hypertrophy is frequently associated with high blood pressure values adversely affecting, from a pathophysiological and prognostic view point, the clinical evolution of the hypertensive disease. From a pathophysiological view point, it has been reported that a pathologic increase in cardiac wall thickness not only impairs diastolic function, coronary circulation and reflex control of circulation exerted by cardiopulmonary volume receptors, but also enhances cardiac work and myocardial oxygen consumption. From a clinical view point, cardiac hypertrophy has been shown to increase the risk of occurrence of cardiac arrhythmias, myocardial infarction, heart failure and sudden cardiac death. Antihypertensive drugs, such as ACE-inhibitors, calcium antagonists and alpha and beta-blocking agents, by reducing high blood pressure values and concomitantly by favouring the regression of the echo- and electrocardiographic signs of cardiac hypertrophy, have been shown to physiologically restore normal cardiac function and reflex homeostatic cardiovascular control.

Heart Failure↗
PubMed1993

Evaluating sympathetic activity in human hypertension.

AIM: To review the use of plasma norepinephrine to evaluate sympathetic activity in humans, and to discuss the improvement in assessment of human sympathetic activity brought about by the norepinephrine spillover method and by microneurography. METHOD: Literature survey. RESULTS: These methods have limitations, and an accurate assessment of sympathetic cardiovascular control should not be limited to an investigation of sympathetic nerve firing or norepinephrine secretion but include cardiac and vascular responses. These responses can be assessed by traditional pharmacological means (for example, a reduction in vascular resistance induced by alpha-adrenergic blockade) or by a variety of approaches aimed at examining sympathetic cardiovascular modulation in a more integrated fashion, such as the recently developed power spectrum analysis of blood pressure and heart rate. CONCLUSION: The sensitivity and specificity of all these methods is still under investigation, but in almost every case an increase in sympathetic cardiovascular influence has been reported to occur in hypertension, indicating that sympathetic activation has a pathogenic effect on this condition.

Blood Pressure↗