F. Tosello

Ascending aortic dilatation, arterial stiffness and cardiac organ damage in essential hypertension.

Objectives: The objectives of this study were to evaluate the prevalence of dilatation of proximal ascending aorta (pAA) in essential hypertensive patients and the association between pAA dilatation, arterial stiffness and left ventricular hypertrophy. Background: Few data are available regarding patients with pAA dilatation in arterial hypertension. It is not known whether pAA dilatation may be related to increased left ventricular mass and what the relation with central hemodynamics and arterial stiffness would be. Methods: A total of 345 untreated and treated essential hypertensive patients (mean age, 54.3 ± 11 years) were considered for this analysis. We measured pulsatile hemodynamic parameters directly using tonometry, and the proximal aortic diameters through ultrasound imaging (echocardiography). Results: Prevalence of pAA dilatation was 17%. Peripheral hemodynamic parameters were similar in patients with and without ascending aorta dilatation. We observed a slight increase of central systolic (129.81 ± 15.4 vs. 125.02 ± 14.7 mmHg; P = 0.02) and pulse pressure (45.02 ± 10.4 vs. 42 ± 9.54 mmHg; P = 0.02) in patients with pAA dilatation. Pulse wave velocity (9.26 ± 2.33 vs. 7.70 ± 1.69 m/s; P < 0.0001), as well as the augmentation index (25.86 ± 10.2 vs. 19.41 ± 9.52%; P < 0.0001), was significantly greater in patients with pAA dilatation. Finally, left ventricular hypertrophy was thrice as frequent (32.8 vs. 13.4%; P < 0.0001) compared to hypertensive patients without aortic dilatation. Conclusion: This study shows a high prevalence (17%) of ascending aortic dilatation in patients affected by essential hypertension, without further complications. Dilatation of the ascending aorta is associated both to an increased left ventricular mass and arterial stiffness.

Prolonged QT interval and reduced heart rate variability in patients with uncomplicated essential hypertension.

A prolonged QT interval is a risk factor for ischemic heart disease in hypertensive subjects. Heart rate variability (HRV) is both an index of autonomic function and an important prognostic factor in several diseases. The aim of the present study was to evaluate the relation between a prolonged QT interval and autonomic nervous system function in patients with untreated uncomplicated essential hypertension. Two hundred and fifteen untreated patients with essential hypertension underwent a Holter ECG equipped with software dedicated to HRV and QT analyses. Nine percent of the patients showed a corrected QT (QTc) ≥440 ms. The HRV indexes in the time domain (SDNN, SDNN index, RMSSD, and pNN50) were significantly reduced in the patients with a prolonged QTc compared to those with a normal QTc (SDNN 24 h: 126.4±29.9 vs. 143.9±35.4 ms, p=0.02; SDNN index [nighttime]: 85.9±32.4 vs. 115.5±36.7 ms, p=0.0006; RMSSD 24 h: 22.2±7.7 vs. 31.2±13.0 ms, p=0.0007; pNN50 24 h: 4.4±4.9 vs. 9.7±8.4%, p=0.0006). The linear correlation analysis between QTc length and HRV parameters showed a significant negative correlation with all the time-domain indexes. Such a correlation was maintained for RMSSD 24 h, pNN50 24 h and SDNN index (nighttime) after correction for gender and age. The present study shows that, even prior to the development of cardiac hypertensive disease, a prolongation of the QTc and a reduced HRV, both markers of cardiovascular risk, coexist in a proportion of patients with untreated essential hypertension. Further studies are warranted to evaluate whether the combination of such markers can identify hypertensive patients at risk for life-threatening arrhythmias and sudden death.

Arterial stiffness: from physiology to clinical implications.

Current European guidelines for the management of arterial hypertension introduce the assessment of arterial stiffness by pulse wave velocity (PWV) as an index of hypertension-related cardiovascular target organ damage. An increase in arterial stiffness is related to haemodynamic modifications at the level of the aorta, leading to a rise in cardiac afterload, a reduction in coronary perfusion and an overstretch of the aortic walls. An increasing number of studies have demonstrated the accuracy of PWV as an independent predictor of cardiovascular events and cardiovascular mortality in patients with different co-morbidities and cardiovascular risk. Many strategies have demonstrated their efficacy in preventing arterial stiffening; therapy of arterial hypertension is the mainstay in the management of patients with increased PWV and altered pulse wave reflection. Literature has clearly shown the specific efficacy of drugs interfering with the renin-angiotensin-aldosterone system and calcium-channel blockers in the control of central haemodynamics, particularly when compared with β-blockers (β-adrenoceptor antagonists). The same action has not yet been demonstrated on PWV. Further studies are needed to assess the real relative efficacy of different drug classes on the management of arterial stiffness and the clinical and prognostic relevance of these therapies.

Antiproton-helium annihilation around 45 MeV/c

Abstract The p ¯ 4 He annihilation cross section averaged over the interval 40–50 MeV/c has been measured using a streamer chamber in a magnetic field. The measured value is 1342±250 mb. It agrees with a behaviour like 1/p of the annihilation cross section. Our result has been obtained at the lowest momentum achieved till now in measurements of antiproton annihilation in flight.

Aortic root dilatation in essential hypertension: prevalence according to new reference values.

Background: Aortic root dilatation (ARD) and arterial hypertension represent two important risk factors for aortic dissection: prevalence of observed ARD is increasing – up to 12% in the latest available reports. A recently published work tested on a good number of healthy individuals new reference ranges for aortic root dimensions, suggesting new reference values with corrections for age, gender, height (pHeight) or body surface area (pBSA). Aim: The aim of the study was to evaluate the prevalence of ARD in hypertensive patients using various criteria. Methods: A total of 1076 untreated and treated essential hypertensive patients (mean age, 52.5 ± 2 years) were considered for this analysis. We measured proximal aortic diameters using ultrasound imaging (echocardiography). ARD was defined in three ways. First, when the observed aortic diameter was larger than that predicted for age, sex, and BSA (pBSA), second when larger than predicted by height (pHeight), and third when the aortic diameter to BSA ratio (ASi) was at least 2.1 cm/m2. Results: A total of 237 patients (22% of the study population) showed at least one among the three different criteria defining aortic dilatation. Prevalence of ARD, considering singularly each one of the criteria, varied between 12.8% (pBSA) and 16.9% (pHeight). Conclusion: Our study demonstrated a prevalence of ARD higher than previously reported. Our data suggest, therefore, the necessity of a correct choice of the diagnostic criterion that has to be applied in the single patient for definition of ARD. In particular, using the criterion pHeight in obese patients, we may avoid underdiagnosis of this condition.

Aortic size index enlargement is associated with central hemodynamics in essential hypertension.

The aim of this study was to evaluate the association between brachial and central blood pressure (bBP and cBP) levels and aortic root dilatation (ARD) in essential hypertensive patients. A total of 190 untreated and treated essential hypertensive patients (mean age, 55±11 years) were considered for this analysis. We measured pulsatile hemodynamics and the proximal aortic diameter directly using tonometry, ultrasound imaging (echocardiography) and Doppler. Ninety-one hypertensive patients had an ARD (defined as aortic size index (ASi)>2 cm/m2). Central hemodynamic variables were significantly associated with ASi. Patients with increased ASi were significantly older (60±10 vs. 50±11 years, P<0.0001) and had higher levels of the augmentation index (AIx; 28±10 vs. 21±10 P<0.0001), augmentation pressure (AP; 13±6 vs. 8±5 mm Hg, P<0.0001), and central pulse pressure (cPP; 44±10 vs. 39±8 mm Hg, P<0.0001) compared with patients with normal ASi. In a logistic regression analysis, the AIx was the only significant predictor of ASi. In hypertensive patients, the AIx and cBP were associated with ARD, whereas the bBP was not. Patients with an increased ASi may lose part of the elastic properties of the aorta, demonstrating a strict correlation between ASi and central hemodynamic indexes, in particular, the cPP and AIx.

Cardiac Organ Damage and Arterial Stiffness in Autonomic Failure: Comparison With Essential Hypertension

Autonomic failure (AF) is characterized by orthostatic hypotension, supine hypertension, and increased blood pressure (BP) variability. AF patients develop cardiac organ damage, similarly to essential hypertension (EH), and have higher arterial stiffness than healthy controls. Determinants of cardiovascular organ damage in AF are not well known: both BP variability and mean BP values may be involved. The aim of the study was to evaluate cardiac organ damage, arterial stiffness, and central hemodynamics in AF, compared with EH subjects with similar 24-hour BP and a group of healthy controls, and to evaluate determinants of target organ damage in patients with AF. Twenty-seven patients with primary AF were studied (mean age, 65.7±11.2 years) using transthoracic echocardiography, carotid-femoral pulse wave velocity, central hemodynamics, and 24-hour ambulatory BP monitoring. They were compared with 27 EH subjects matched for age, sex, and 24-hour mean BP and with 27 healthy controls. AF and EH had similar left ventricular mass (101.6±33.3 versus 97.7±28.1 g/m2, P=0.59) and carotid–femoral pulse wave velocity (9.3±1.8 versus 9.2±3.0 m/s, P=0.93); both parameters were significantly lower in healthy controls (P<0.01). Compared with EH, AF patients had higher augmentation index (31.0±7.6% versus 26.1±9.2%, P=0.04) and central BP values. Nighttime systolic BP and 24-hour systolic BP predicted organ damage, independent of BP variability. AF patients develop hypertensive heart disease and increased arterial stiffness, similar to EH with comparable mean BP values. Twenty-four–hour and nighttime systolic BP were determinants of cardiovascular damage, independent of BP variability.Autonomic failure (AF) is characterized by orthostatic hypotension, supine hypertension, and increased blood pressure (BP) variability. AF patients develop cardiac organ damage, similarly to essential hypertension (EH), and have higher arterial stiffness than healthy controls. Determinants of cardiovascular organ damage in AF are not well known: both BP variability and mean BP values may be involved. The aim of the study was to evaluate cardiac organ damage, arterial stiffness, and central hemodynamics in AF, compared with EH subjects with similar 24-hour BP and a group of healthy controls, and to evaluate determinants of target organ damage in patients with AF. Twenty-seven patients with primary AF were studied (mean age, 65.7±11.2 years) using transthoracic echocardiography, carotid-femoral pulse wave velocity, central hemodynamics, and 24-hour ambulatory BP monitoring. They were compared with 27 EH subjects matched for age, sex, and 24-hour mean BP and with 27 healthy controls. AF and EH had similar left ventricular mass (101.6±33.3 versus 97.7±28.1 g/m2, P =0.59) and carotid–femoral pulse wave velocity (9.3±1.8 versus 9.2±3.0 m/s, P =0.93); both parameters were significantly lower in healthy controls ( P <0.01). Compared with EH, AF patients had higher augmentation index (31.0±7.6% versus 26.1±9.2%, P =0.04) and central BP values. Nighttime systolic BP and 24-hour systolic BP predicted organ damage, independent of BP variability. AF patients develop hypertensive heart disease and increased arterial stiffness, similar to EH with comparable mean BP values. Twenty-four–hour and nighttime systolic BP were determinants of cardiovascular damage, independent of BP variability. # Novelty and Significance {#article-title-49}

Modelling and Subject-Specific Validation of the Heart-Arterial Tree System

A modeling approach integrated with a novel subject-specific characterization is here proposed for the assessment of hemodynamic values of the arterial tree. A 1D model is adopted to characterize large-to-medium arteries, while the left ventricle, aortic valve and distal micro-circulation sectors are described by lumped submodels. A new velocity profile and a new formulation of the non-linear viscoelastic constitutive relation suitable for the {Q, A} modeling are also proposed. The model is firstly verified semi-quantitatively against literature data. A simple but effective procedure for obtaining subject-specific model characterization from non-invasive measurements is then designed. A detailed subject-specific validation against in vivo measurements from a population of six healthy young men is also performed. Several key quantities of heart dynamics—mean ejected flow, ejection fraction, and left-ventricular end-diastolic, end-systolic and stroke volumes—and the pressure waveforms (at the central, radial, brachial, femoral, and posterior tibial sites) are compared with measured data. Mean errors around 5 and 8%, obtained for the heart and arterial quantities, respectively, testify the effectiveness of the model and its subject-specific characterization.

anti-p He-3 REACTION CROSS-SECTION AT 200-MeV/c

Abstract Inelastic p - 3 He events at 192.8 MeV/ c are detected with a self-shunted streamer chamber. The measured reaction cross section is 392±23.8mb. This result is briefly discussed and compared with other reaction cross sections for low-energy p with light nuclei.

n̄p annihilation in flight in two mesons in the momentum range between 50 and 400 MeV/c with OBELIX

Results on np annihilation frequencies into π + π 0 , π + η and K + K s final states in the n momentum range between 50 and 400 MeV/c are presented. Information about np annihilation dynamics at low energy have been extracted as well as the first determination of the D-wave contribution to the annihilation in flight below 400 MeV/c . This result is compared with an independent analysis of the np annihilation cross section data.