Ultrasonographic backscatter of the carotid artery wall in patients with HIV infection: a pilot study.

AIMS: The aim of our study was to measure carotid intima-media thickness (cIMT) and risk factors associated with its development and progression, and to evaluate arterial wall characteristics through integrated backscatter analysis (IBS) in HIV patients. METHODS: Perspective cohort study enrolling 44 HIV patients treated with antiretroviral drugs who underwent standard B Mode cIMT measurement and tissue characterization of carotid wall by means of dedicated software by acoustic densitometry, at time 0 and 2 years later. MAJOR FINDINGS: Cross-sectional evaluation performed at baseline found that cIMT value correlated significantly with age (r = 0.42, p = 0.005) and systolic blood pressure (r = 0.31, p = 0.04). No correlation was found between cIMT and CD4, HIV-RNA, triglycerides or total cholesterol. There was no difference between the group with versus the group with no protease inhibitors treatment. cIMT progression during 2 years of observation was statistically significant (median, interquartile range [IQR]: 0.005, 0-0.031). No correlation was found between IBS and duration of disease and kind of therapy, whereas a significant association was found between cIMT and IBS (r = 0.33, p = 0.03). No noticeable changes of IBS were observed during 2 years observation. CONCLUSIONS: Classic risk factors greatly affect cIMT than time of HIV infection, duration of antiretroviral therapy exposure and use of protease inhibitors. IBS is a promising technique for the evaluation of arterial wall composition in HIV patients.

Simultaneous measurement of beat-to-beat carotid diameter and pressure changes to assess arterial mechanical properties.

Use of local arterial distensibility measurements by change in carotid artery diameter divided by pulse pressure has limitations because blood pressure is often taken in a vessel distant or at a time different from where and when change in diameter is taken. In 92 subjects (23 to 91 years of age), carotid artery diameter was continuously measured ecographically, whereas blood pressure was continuously measured simultaneously tonometrically on the contralateral artery, the 2 signals being synchronized via 2 EKGs. Within each cardiac cycle, there was a linear relationship between the changes in vessel diameter and the changes in blood pressure during either the protomesosystole or the diastole after the dicrotic notch. The diastolic slope was displaced upward and steeper than the systolic slope, the pressure-diameter loop showing a hysteresis. Both slopes showed a high reproducibility when data were averaged over a several-second period. There were small differences between consecutive cardiac cycles, suggesting that modulation of arterial mechanical response to continuous changes in intravascular pressure may undergo physiological variations. In the 92 subjects, systolic and diastolic slopes correlated significantly with distensibility values obtained by Reneman formula and exhibited a close inverse relationship with each subject's age and systolic blood pressure, thereby showing the ability to reflect age- and pressure-dependent large artery stiffening. This method may allow precise assessment of man's arterial mechanical properties within each cardiac cycle. This highly dynamic assessment may help to collect information on properties of normal and altered large elastic arteries and the mechanisms involved in disease.

Increased arterial stiffness in normoglycemic normotensive offspring of type 2 diabetic parents.

Diabetes is associated with a reduction of arterial distensibility. Limited information exists regarding whether or how early this appears in the course of the disease. We studied 54 normoglycemic, normotensive, healthy offspring of 2 parents with type 2 diabetes mellitus and 55 age- and sex-matched healthy control subjects. Carotid diastolic diameter and systodiastolic change were measured by echo tracking (Wall Track System) and wall thickness by echocolor Doppler (Sonos 5500, Philips). Pulse pressure was measured by a semiautomatic device positioned on the brachial artery and arterial distensibility calculated by Reneman formula. Blood pressure, blood glucose, glycohemoglobin, and insulin sensitivity (homeostasis model assessment index) were normal or only slightly elevated and by and large similar in the 2 groups. Compared with control subjects, offspring of diabetic parents showed similar carotid diameters at diastole and a reduced increase in carotid diameter at systole (-16%), a reduced carotid artery distensibility (-30%), and an increased pulse pressure (+21.8%), all differences being statistically significant (P<0.05) and persisting in subgroups with elevated or normal body mass index values (<25 and >or=25 kg/m(2)). Carotid artery wall thickness was not different between the 2 groups. Thus, subjects with predisposition to diabetes show carotid artery stiffening even in the absence of blood pressure alterations, as well as substantial alterations of glucose metabolism, body mass index, and changes in carotid wall thickness. This suggests that, in diabetes, alterations in arterial mechanical properties represent an early phenomenon, which may occur in the absence of metabolic and blood pressure alterations.

Effects of prostaglandin E1alpha cyclodextrin [corrected] treatment on endothelial dysfunction in patients with systemic sclerosis.

OBJECTIVE: Systemic sclerosis (SSc) is characterized by an altered nitric oxide (NO): endothelin I ratio and by endothelial dysfunction. AIMS: To verify the effects of prostaglandin E1 (PGE1) alpha-cyclodestrin treatment on endothelial function, quantified as flow-mediated dilation (FMD) of the radial artery. METHODS: In 16 women with SSc (age 57 +/- 2.7 years, means +/- SE) in whom a diagnosis of SSc had been made several years earlier (7.1 +/- 1.2 years), FMD was evaluated by an echotracking technique on the radial artery, using trinitroglycerin vasodilation as a non-endothelial measure of the vessel's ability to increase its diameter maximally. FMD was evaluated after 4 months washout period and after 4 months cyclic infusion of PGE1 alpha-cyclodestrin. Expired NO was measured at the same time. RESULTS: PGE1 alpha-cyclodestrin cyclic infusions did not modify systolic and diastolic blood pressure, heart rate or trinitroglycerin radial artery vasodilation. On the other hand, it induced a marked and significant increase in FMD of the radial artery, which was also accompanied by an increase in blood flow and expired NO. CONCLUSIONS: Endothelial dysfunction and reduced FMD associated with SSc are improved by cyclic treatment with PGE1 alpha-cyclodestrin. This effect occurs together with a concomitant increase in expired NO, suggesting its direct positive influence on endothelial function. It may also partly explain the clinical beneficial effect of the drug in SSc.

Relationship between arterial distensibility and coronary atherosclerosis in angina patients.

OBJECTIVE: Arterial stiffening is associated with an increased risk of cardiovascular disease. However, limited evidence exists on whether it also relates to subclinical atherosclerosis, thereby providing a non-invasive marker of the overall cardiovascular status. The aim of the present study was to provide information on arterial stiffening in angina patients in whom angiographic evaluation allowed quantification of coronary atherosclerosis. METHODS: We studied 101 patients with angina from a large number admitted to our hospital for coronary angiography. In each patient, radial (RA), subdiaphragmatic aorta (AO) and carotid (CA) distensibility (Dist) were measured by an ultrasonic device, following ultrasonic exclusion of atherosclerotic lesions at these specific sites. Patients were classified into three groups according to the angiographic findings: (i) no significant coronary lesions (lumen obstruction < 50%, group A); (ii) one (group B); and (iii) two or three (group C) coronary vessels with hemodynamic significant plaques (lumen obstruction > 50%). RESULTS: Age, male prevalence, previous cardiovascular disease and interventions were progressively greater or more common from group A to C, whereas several other risk factors (plasma glucose, serum cholesterol, smoking, history of hypertension, etc.) did not differ between the three groups or between the group with single vessel (B) versus the group with multivessel disease (C). CA and AO Dist decreased progressively from group A to C with a significant relationship in the group as a whole between distensibility values and the number of diseased vessels. The progressive decrease in AO Dist from group A to C remained significant after adjustment for variables that showed between-group differences (such as gender, age and systolic blood pressure) and the ROC curve showed it to be a more sensitive and specific marker of coronary atherosclerosis than CA Dist. RA Dist was similar in the three groups and showed no relationship with the number of diseased vessels in the group as a whole. CONCLUSION: In patients with angina, AO and CA Dist are related to the severity of coronary atherosclerosis, with the relationship being better for alterations in aortic than in carotid mechanical properties. Large elastic artery (and in particular aortic) stiffening can thus be considered as a marker of the severity of coronary atherosclerosis, providing non-invasive obtainable information on the need to proceed with further clinical examinations.

Arterial stiffening influence of sympathetic nerve activity: evidence from hand transplantation in humans.

Studies in animals and humans suggest that sympathetic activity exerts a stiffening influence on large and middle-sized artery walls. We sought to obtain further evidence on this issue by measuring radial artery distensibility in an allotransplanted and thus denervated hand using the contralateral artery as control. In 2 men, blood pressure was measured by a semiautomatic device (Dinamap). Diastolic diameter, systo-diastolic diameter excursion (ultrasound Wall Track system), and distensibility (Reneman formula) of both radial arteries were measured at a level corresponding to 4 cm below the suture of the transplanted hand 40 days after surgery and every 4 weeks for the next 6 months. After surgery, systo-diastolic diameter excursion and distensibility were much greater in the transplanted radial artery than in the contralateral vessel, reaching values similar to the contralateral ones after 4 months, when signs of reinnervation of the transplanted hands had appeared. Radial deinnervation was accompanied by an increased arterial distensibility, which provides further evidence of the sympathetic stiffening effect on arterial wall in humans.

Different relation between 24-h blood pressure and distensibility at different peripheral arteries. Data from the European Lacidipine Study on Atherosclerosis (ELSA).

INTRODUCTION: The European Lacidipine Study on Atherosclerosis (ELSA) has been planned to investigate the effect of reduction in office and ambulatory blood pressure by lacidipine versus atenolol on carotid artery wall thickness in mild to moderate essential hypertensive patients with no metabolic abnormalities. One prespecified sub-study of ELSA focused on measurements of arterial distensibility in the carotid as well as in the radial artery to determine the relationship of functional arterial properties with office versus ambulatory blood pressure (BP) values as well as the correspondence between functional and structural arterial alterations. METHODS: The sub-study was conducted on 124 patients recruited in four centres (Monza-Milan, Paris, Grenoble and Glasgow). BP was measured both by a mercury sphygmomanometer and by 24-h ambulatory monitoring. Common carotid artery wall thickness was measured by certified sonographers as described in the main study. Common carotid and radial artery distensibility were obtained by echotracking techniques, which allowed to relate changes in arterial diameter with systo-diastolic BP changes. RESULTS: Carotid artery wall distensibility showed (1) a negative correlation with office and more so 24-h average systolic BP (r = -0.45 and -0.58, P < 0.008 and 0.001) but not with office or 24-h diastolic BP) and (2) a negative correlation with the corresponding wall thickness (r = -0.47, P < 0.005). In contrast, at the radial artery level distensibility and thickness showed no correlation with each other and with BP. Carotid (but not radial) artery distensibility also correlated with ambulatory systolic BP variability but the correlation was lost after adjustment for age and mean BP values. CONCLUSION: These data suggest that stiffening of large elastic artery is reflected more by ambulatory than office BP elevations, systolic BP being much more important than diastolic. Alterations of large elastic arteries function is related to structural wall changes. Functional and structural properties of middle-size muscle arteries are independent of BP.

Nonpharmacologic treatment of hypertension by respiratory exercise in the home setting.

BACKGROUND: Device-guided breathing exercises at home have a potential to become a nonpharmacologic treatment of high blood pressure (BP). The aim of this study was to evaluate the impact of device-guided breathing exercises on both office and home BP. METHODS: A total of 79 mild hypertensive individuals, either medicated or unmedicated, with BP > 140/90 mm Hg were enrolled. After a 2-week run-in phase, in both the control and treatment groups daily home blood pressure was monitored for 8 weeks. The treatment group also engaged in 15-min daily sessions with device-guided breathing exercises. RESULTS: A total of 47 treatment patients and 26 control subjects completed the study. In the control group both office and home BP showed small nonsignificant reductions. Device-guided breathing exercises reduced mean office BP (systolic/diastolic) by 5.5/3.6 mm Hg (P < .05 for diastolic) and mean home BP by 5.4/3.2 mm Hg (P < .001 for both). Home BP response reached a plateau after 3 weeks. CONCLUSION: Our data show that device-guided breathing exercises have an antihypertensive effect that can be seen in conditions closer to daily life than the setting of the physician's office.

Effects of heart rate changes on arterial distensibility in humans.

In rats, an increase in heart rate by pacing is accompanied by progressive large-artery stiffening. Whether this is also the case in humans is unknown. We enrolled 20 patients who were chronically implanted with a pacemaker because of atrioventricular block or sick sinus syndrome. Arterial distensibility was measured by an echo-tracking device. In 10 patients, the evaluation was performed on the radial artery by using continuous finger blood pressure measurements, whereas in the remaining 10 patients, the common carotid artery was studied with a semiautomatic measure of brachial artery blood pressure. Diastolic diameter, systodiastolic diameter change, and distensibility were obtained at baseline (heart rate 63+/-2 beats/min) and after atrial and ventricular sequential pacing at a heart rate of 90 and 110 beats/min. At baseline, the diameter was 7.8+/-0.3 mm in the carotid artery and 2.4+/-0.1 mm in the radial artery; the respective systodiastolic diameter change values were 375.4+/-31.0 and 55.9+/-9.0 (microm) and the distensibility values were 1.4+/-0.1 and 0.7+/-0.1 (1/mm Hg 10-3). Blood pressure and diameter were not significantly modified by increasing heart rate, which markedly modified systodiastolic diameter change and distensibility. In the radial artery, distensibility was reduced by 47% (P<0.05) at a heart rate of 90 beats/min with no further reduction at 110 beats/min. In the carotid artery, distensibility was reduced by 20% at a heart rate of 90 beats/min (P<0.05) with a further reduction at 110 beats/min (45%, P<0.05). These data provide the first evidence in humans that acute increases in heart rate markedly affect arterial distensibility and that this occurs in both large- and middle-size muscle arteries within the range of "normal" heart rate values.

[Study of arterial distensibility in man. Modulating mechanisms, pathological conditions and effects of treatment]. / Studio della distensibilità arteriosa nell'uomo. Quali i meccanismi di modulazione, come varia in condizioni patologiche ed effetto della terapia.

The reduction of large arterial distensibility has several adverse consequences for the cardiovascular system. This paper reviews the evidence we have obtained by measuring distensibility through quantification of changes in arterial diameter vs blood pressure changes at large elastic and middle size muscle artery sites. Evidence shows that arterial distensibility is reduced in conditions such as hypercholesterolemia, hypertension, diabetes, and congestive heart failure. In some conditions (e.g. hypertension) the alterations are not uniformly distributed in the arteries of different structure and size whereas in others (e.g. diabetes and heart failure) they are widespread. In diabetes evidence is available that distensibility changes occur early in the course of the disease. Evidence is also available that in all above conditions treatment can improve arterial distensibility thereby reversing the initial abnormality. This is due to a variable combination of structural and functional factors. However, technical ability to determine their precise role in distensibility changes in humans is limited.

Effects of hematocrit changes on flow-mediated and metabolic vasodilation in humans.

Endothelial function is noninvasively assessed by measuring nitric oxide-dependent increase in radial artery diameter accompanying the elevation in shear stress induced by increasing blood flow through a short-lasting ischemia of the hand. However, shear stress also depends on blood viscosity, whose changes might thus affect nitric oxide increase in a manner that is not properly reflected by blood flow changes. In 12 subjects with hemochromatosis, we measured ultrasonographically radial artery diameter and blood flow responses to a 4-minute ischemia of the hand. This was done also after removing 500 mL of blood (and concomitantly infusing 500 mL of saline), which significantly (P<0.01) reduced hemoglobin concentration and hematocrit. The increase in blood flow induced by the 4-minute ischemia was similar before and after blood removal (+76% and +80%), which, in contrast, markedly attenuated the accompanying increase in radial artery diameter (+25% versus +13%, P<0.01). Thus, in humans, blood viscosity is involved in the endothelial response to an increase in shear stress. This implies that this response may not be accurately assessed and compared by quantifying the stimulus only through an increase in blood flow.

Radial, carotid and aortic distensibility in congestive heart failure: effects of high-dose angiotensin-converting enzyme inhibitor or low-dose association with angiotensin type 1 receptor blockade.

UNLABELLED: objectives; The aim of this study was to determine whether in patients with congestive heart failure (CHF) a distensibility (Dist) reduction: 1) similarly occurs in different arteries; 2) is related to CHF severity; and 3) is reversible with treatment. background: Several studies suggest that CHF is accompanied by a reduced arterial Dist. METHODS: We measured diameter in radial artery, carotid artery (CA) and abdominal aorta (AO) by echotracking. Distensibility was obtained by relating it to blood pressure. Data were collected in 30 patients with CHF (New York Heart Association functional class I to III) under standard treatment with diuretic, digitalis and angiotensin-converting enzyme (ACE) inhibitor in whom CHF severity was assessed by maximum oxygen consumption (VO(2)max) percentage and in 30 age- and gender-matched controls. Patients with CHF were then randomized to maintain standard treatment (n = 10), double the ACE inhibitor dose (n = 10) or add an angiotensin II antagonist (n = 10) and restudied after two months. RESULTS: Distensibility was markedly reduced in the CHF group in all three vessels (p < 0.01), CA and AO Dist being related to CHF severity (p < 0.05). After two months, Dist did not change in the group maintained under standard treatment, but it increased significantly (p < 0.05) and similarly when the ACE inhibitor dose was doubled or an angiotensin II antagonist was added. CONCLUSIONS: Congestive heart failure is characterized by a reduction of Dist of large-elastic and middle-sized muscular arteries. The reduction of large-elastic artery Dist is related to the CHF severity. These alterations can be reversed by drugs, effectively interfering with the renin-angiotensin system either at the ACE or at the angiotensin receptor level.