Arterial wall remodelling and stiffness in hypertension: heterogeneous aspects

The surge in heart rate and blood pressure at respiratory event termination is dampened in children with down syndrome

BACKGROUND

Children with Down syndrome (DS) have a high prevalence of sleep disordered breathing (SDB) and altered cardiovascular autonomic control. We aimed to analyze the effect of DS on the surge in heart rate (HR) and pulse transit time (PTT, an inverse surrogate measure of blood pressure change) at respiratory event termination.

METHODS

44 children (3-19 y) with DS and 44 typically developing (TD) children matched for SDB severity, age and sex underwent overnight polysomnography. Multilevel modelling determined the effect of DS on HR and PTT changes between a 10s pre-event to the latter half of each respiratory event (late-event) and 15s post-event during NREM and REM, accounting for SDB severity and event length.

RESULTS

The children with DS had a significantly smaller % change in HR late-event to post-event (NREM: DS 26.4 % ± 17.5 % (mean ± SD), TD 30.7 % ± 21.0 %; REM DS 16.9 % ± 15.3 %, TD 21.0 % ± 14.0 %; p < 0.05 for both) compared with TD children for obstructive events, and central events (13.2 % ± 17.0 %, TD 18.8 % ± 17.0 %; p < 0.01) during REM. %change in PTT was significantly smaller in the DS group during NREM and REM from pre-event and late-event to post-event compared with TD children for obstructive and central events.

CONCLUSION

These results suggest children with DS have dampened HR and BP responses to respiratory events compared with TD children. Whether this is symptomatic of autonomic dysfunction or a protective factor for the cardiovascular system in children with DS remains to be elucidated.

Effect of rapid cooling, frozen storage, and thawing on the passive viscoelastic properties and structure of the rat aorta

Biological tissues decay over time after harvesting, which alters their biomechanical properties. This poses logistical challenges for studies investigating passive arterial biomechanics as tissues need to be characterized shortly after excision. Freezing and cryopreservation methods can help alleviate the need for biomechanical testing of fresh tissue in human ex vivo studies. However, these methods tend to eliminate or reduce arterial cell functionality and affect passive biomechanics. Furthermore, their impact on dynamic arterial biomechanics remains unknown despite arterial viscoelastic properties being an integral component contributing to arterial stiffness under in vivo loading conditions. The present study aims to investigate the impact of rapid cooling and subsequent storage at -80 °C on the passive viscoelastic properties of arterial tissue and aid in ascertaining whether this is a suitable method to delay tissue analysis for studies investigating passive arterial biomechanics. Control and frozen abdominal rat aorta segments were quasi-statically and dynamically tested using a biaxial testing set-up. The results were modeled using a constituent-based quasi-linear viscoelastic modeling framework, yielding directional stiffness parameters, individual constituent biomechanical contributions, and a quantification of viscoelastic stiffening under dynamic pressurization conditions. Frozen samples displayed significantly decreased wall thickness, viscoelastic dissipation, viscoelastic stiffening, and significantly decreased circumferential deformation with changes in luminal pressure. Furthermore, frozen samples displayed significantly increased circumferential stiffness, pulse wave velocity, and collagen load bearing. Consequently, these changes should be considered when utilizing this tissue preservation method to delay biomechanical characterization of rat aortic tissue.

Unsupervised deep learning-based displacement estimation for vascular elasticity imaging applications

Objective. Arterial wall stiffness can provide valuable information on the proper function of the cardiovascular system. Ultrasound elasticity imaging techniques have shown great promise as a low-cost and non-invasive tool to enable localized maps of arterial wall stiffness. Such techniques rely upon motion detection algorithms that provide arterial wall displacement estimation.Approach. In this study, we propose an unsupervised deep learning-based approach, originally proposed for image registration, in order to enable improved quality arterial wall displacement estimation at high temporal and spatial resolutions. The performance of the proposed network was assessed through phantom experiments, where various models were trained by using ultrasound RF signals, or B-mode images, as well as different loss functions.Main results. Using the mean square error (MSE) for the training process provided the highest signal-to-noise ratio when training on the B-modes images (30.36 ± 1.14 dB) and highest contrast-to-noise ratio when training on the RF signals (32.84 ± 1.89 dB). In addition, training the model on RF signals demonstrated the capability of providing accurate localized pulse wave velocity (PWV) maps, with a mean relative error (MREPWV) of 3.32 ± 1.80% and anR2 of 0.97 ± 0.03. Finally, the developed model was tested in human common carotid arteriesin vivo, providing accurate tracking of the distension pulse wave propagation, with an MREPWV= 3.86 ± 2.69% andR2 = 0.95 ± 0.03.Significance. In conclusion, a novel displacement estimation approach was presented, showing promise in improving vascular elasticity imaging techniques.

Effects of Testosterone Deficiency and Angiotensin II-Induced Hypertension on the Biomechanics of Intramural Coronary Arteries

BACKGROUND

Andropause and hypertension also increase the risk of coronary artery damage.

AIM

To investigate the effect of testosterone deficiency and hypertension on intramural coronary vessels.

METHODS

4 groups of 8-week-old Sprague-Dawley rats were studied: control male (Co, n=10), orchidectomized male (OCT, n=13), angiotensin (AII) hypertensive male (AII, n=10), and AII hypertensive and OCT (AII + OCT, n=8). Surgical orchidectomy was performed, and an osmotic minipump was inserted for chronic angiotensin II infusion (100 ng/min/kg). After 4 weeks, spontaneous tone and biomechanical properties of the intramural coronary resistance artery were investigated in vitro, by pressure microarteriography.

OUTCOMES

Morphology and biomechanics of the intramural coronaries were evaluated: the outer diameter, wall thickness-to-lumen diameter ratio, and tangential wall stress in the contracted and relaxed states.

RESULTS

The outer diameter was reduced in OCT and AII + OCT groups (on 50 mmHg 315 ± 20 Co; 237 ± 21 OCT; 291 ± 16 AII, and 166 ± 12 μm AII + OCT). The increased wall thickness-to-lumen diameter ratio resulted in lower tangential wall stress in AII + OCT rats (on 50 mmHg 19 ± 2 Co; 24 ± OCT; 26 ± 5 AII, and 9 ± 1 kPa AII + OCT). Spontaneous tone was increased in the hypertensive rats (AII and AII + OCT groups) (on 50 mmHg 7.7 ± 1.8 Co; 6.1 ± 1.4 OCT; 14.5 ± 3.0 AII, and 17.4 ± 4.1 % AII + OCT).

CLINICAL IMPLICATIONS

Andropause alone can be considered as a cardiovascular risk factor that will further exacerbate vascular damage in hypertension.

STRENGTHS & LIMITATIONS

A limitation of our study is that it was performed on relatively young rats, and the conclusions might not apply to coronary remodelling in older animals with slower adaptation processes.

CONCLUSIONS

Testosterone deficiency and hypertension damage the mechanical adaptation of the vessel wall additively: double noxa caused inward eutrophic remodeling and increased tone. Jósvai A, Török M, Mátrai M, et al. Effects of Testosterone Deficiency and Angiotensin II-Induced Hypertension on the Biomechanics of Intramural Coronary Arteries. J Sex Med 2020;17:2322-2330.

In Vitro Validation of 4D Flow MRI for Local Pulse Wave Velocity Estimation

PURPOSE

Arterial stiffness has predictive value for cardiovascular disease (CVD). Local artery stiffness can provide insight on CVD pathology and may be useful for diagnosis and prognosis. However, current methods are invasive, require real-time expertise for measurement, or are limited by arterial region. 4D Flow MRI can non-invasively measure local stiffness by estimating local pulse wave velocity (PWV). This technique can be applied to vascular regions, previously accessible only by invasive stiffness measurement methods. MRI PWV data can also be analyzed post-exam. However, 4D Flow MRI requires validation before it is used in vivo to measure local PWV.

METHODS

PWV, calculated from 4D Flow MRI and a benchtop experiment, was compared with petersons elastic modulus (PEM) of in vitro models. PEM was calculated using high-speed camera images and pressure transducers. Three transit-time algorithms were analyzed for PWV measurement accuracy and precision.

RESULTS

PWV from 4D Flow MRI and reference benchtop experiments show strong correlation with PEM (R² = 0.99). The cross correlation transit-time algorithm showed the lowest percent difference between 4D Flow MRI and benchtop experiments (4-7%), and the point to point of 50% upstroke algorithm had the highest transit-time vs. distance data average R² (0.845).

CONCLUSION

4D Flow MRI is a feasible method for estimating local PWV in simple in vitro models and is a viable tool for clinical analysis. In addition, choice in transit-time algorithm depends on flow waveform shape and arterial region. This study strengthens the validity of 4D Flow MRI local PWV measurement in simple models. However, this technique requires validation in more complex models before it is used in vivo.

Estrogen therapy may counterbalance eutrophic remodeling of coronary arteries and increase bradykinin relaxation in a rat model of menopausal hypertension

Objective:

Hypertension causes adverse remodeling and vasomotor alterations in coronaries. Hormones such as estrogen may help counterbalance some of these effects. The aim of this study was to analyze the effects of ovariectomy and estrogen therapy in a rat model of menopausal hypertension induced by angiotensin II (AII).

Methods:

We investigated diameter, tone, and mechanics of intramural coronaries taken from ovariectomized female rats (n = 11) that received chronic AII treatment to induce hypertension, and compared the results with those found in female rats that were also given estrogen therapy (n = 11). The “hypertensive control” group (n = 11) underwent an abdominal sham operation, and received AII. After 4 weeks of AII treatment, side branches of left anterior descendent coronary (approximately 200 μm in diameter) were isolated, cannulated with plastic microcannulas at both ends, and studied in vitro in a vessel chamber. The inner and outer diameter of the arteries were measured by microangiometry, and spontenuous tone, wall thickness, wall cross-sectional area, tangential stress, incremental distensibility, circumferential incremental elastic modulus, thromboxane agonist-induced tone, and bradykinin-induced dilation were calculated.

Results:

In hypertension, intramural small coronaries show inward eutrophic remodeling after ovariectomy comparing with hypertensive controls. Estrogen therapy had an opposite effect on vessel diameter. Hormone therapy led to an increase in spontaneous tone, allowing for greater dilatative capacity.

Conclusions:

Estrogen may therefore be considered to counterbalance some of the adverse changes seen in the wall of intramural coronaries in the early stages of chronic hypertension.

Stiffness of the large arteries in individuals with and without Down syndrome

BACKGROUND

Down syndrome is known to cause premature aging in several organ systems. However, it remains unclear whether this aging effect also affects the structure and function of the large arterial trunks. In this controlled study, the possibility of changes in the large arteries due to aging was evaluated in patients with Down syndrome.

METHODS

Eighty-two subjects of both genders were selected. The Down syndrome group had 41 active subjects consisting of 19 males and 22 females (mean age 21 ± 1, range 13-42 years) without cardiovascular complications and who did not use vasoactive drugs. The control group consisted of 41 healthy individuals without trisomy 21 of the same gender and age as the Down syndrome group and who did not use vasoactive medication. Carotid-femoral pulse wave velocity was obtained as an index of aortic stiffness using an automatic noninvasive method.

RESULTS

Individuals with Down syndrome had significantly lower blood pressure than those in the control group. Systolic blood pressure for the Down syndrome group and control group was 106 ± 2 mmHg vs 117 ± 2 mmHg (P < 0.001), respectively; diastolic blood pressure was 66 ± 2 mmHg vs 77 ± 2 mmHg (P < 0.001); and mean arterial pressure was 80 ± 1 mmHg vs 90 ± 1 mmHg (P < 0.001). Only age and systolic blood pressure were shown to correlate significantly with pulse wave velocity, but the slopes of the linear regression curves of these two variables showed no significant difference between the two study groups. Pulse wave velocity, which was initially significantly lower in the Down syndrome group (7.51 ± 0.14 m/s vs 7.84 ± 0.12 m/s; P <0.05), was similar between the groups after systolic blood pressure adjustment (7.62 ± 0.13 m/s vs 7.73 ± 0.13 m/s).

CONCLUSION

Despite evidence in the literature that patients with Down syndrome undergo early aging, this process does not seem to affect the large arterial trunks, given that values of carotid-femoral pulse wave velocity were similar in individuals with or without trisomy 21. Considering that Down syndrome presents with chronic hypotension, it is reasonable to propose that the prolonged reduction of arterial distending pressure may contribute to functional preservation of the arteries in patients with Down syndrome.

Right coronary artery becomes stiffer with increase in elastin and collagen in right ventricular hypertrophy

Changes in blood flow influence the structure, function, mechanical properties, and remodeling of arteries. The objective of the present study was to investigate the role of increased blood flow on the biaxial incremental elastic moduli of the porcine right coronary artery (RCA) and to determine the microstructural basis for the changes in moduli. We hypothesized that an increase in RCA flow will lead to increased stiffness in conjunction with remodeling of elastin and collagen in the vessel wall. The control and experimental groups consisted of five RCA vessels each. The RCA of the experimental group was exposed to 4 wk of flow-overload in right ventricular hypertrophy induced by pulmonary artery banding. Stress-strain relationships were determined and the incremental elastic moduli were derived in the circumferential, axial, and cross directions. The results show a significant increase in the elastic moduli in the circumferential (262.7 +/- 15.7 vs. 120.2 +/- 12.4 kPa; P < 0.001), axial (177.8 +/- 25.5 vs. 100.3 +/- 11.9 kPa; P = 0.025), and cross directions (104.8 +/- 8.2 vs. 68.2 +/- 8.6 kPa; P = 0.016) of the experimental RCA compared with controls. Multiphoton microscopy was used to assess the changes in elastin and collagen content in the media and adventitia of the vessel wall. We found a significant increase in elastin and collagen area fraction particularly in the adventitial layer. These data suggest stiffening of the vessel wall as a result of increased elastin and more predominantly collagen.

Relationship between birthweight and arterial elasticity in childhood

There is a considerable debate about the potential influence of ‘fetal programming’ on cardiovascular diseases in adulthood. In the present prospective epidemiological cohort study, the relationship between birthweight and arterial elasticity in 472 children between 5 and 8 years of age was assessed. LAEI (large artery elasticity index), SAEI (small artery elasticity index) and BP (blood pressure) were assessed using the HDI/PulseWave™ CR-2000 CardioVascular Profiling System. Blood concentrations of glucose, total cholesterol and its fractions [LDL (low-density lipoprotein)-cholesterol and HDL (high-density lipoprotein)-cholesterol] and triacylglycerols (triglycerides) were determined by automated enzymatic methods. Insulin was assessed by a chemiluminescent method, insulin resistance by HOMA (homoeostasis model assessment) and CRP (C-reactive protein) by immunonephelometry. Two linear regression models were applied to investigate the relationship between the outcomes, LAEI and SAEI, and the following variables: birthweight, gestational age, glucose, LDL-cholesterol, HDL-cholesterol, triacylglycerols, insulin, CRP, HOMA, age, gender, waist circumference, per capita income, SBP (systolic BP) and DBP (diastolic BP). LAEI was positively associated with birthweight (P=0.036), waist circumference (P<0.001) and age (P<0.001), and negatively associated with CRP (P=0.024) and SBP (P<0.001). SAEI was positively associated with birthweight (P=0.04), waist circumference (P=0.001) and age (P<0.001), and negatively associated with DBP (P<0.001). Arterial elasticity was decreased in apparently healthy children who had lower birthweights, indicating an earlier atherogenetic susceptibility to cardiovascular diseases in adolescence and adult life. Possible explanations for the results include changes in angiogenesis during critical phases of intrauterine life caused by periods of fetal growth inhibition and local haemodynamic anomalies as a way of adaptation to abnormal pressure and flow.

Synchrony between circular and longitudinal muscle contractions during peristalsis in normal subjects

The current understanding is that longitudinal muscle contraction begins before and outlasts circular muscle contraction during esophageal peristalsis in normal subjects. The goal of our study was to reassess the relationship between the contractility of two muscle layers using novel ways to look at the muscle contraction. We studied normal subjects using synchronized high-frequency ultrasound imaging and manometry. Swallow-induced peristalsis was recorded at 5 and 10 cm above the lower esophageal sphincter (LES). Ultrasound (US) images were analyzed for muscle cross-sectional area (CSA) and circularity index of the esophagus during various phases of esophageal contraction. A plot of the M mode US image, muscle CSA, and esophageal circularity index was developed to assess the temporal correlation between various parameters. The muscle CSA wave began before and lasted longer than the contraction pressure wave at both 5 and 10 cm above the LES. M mode US images revealed that the onset of muscle CSA wave was temporally aligned with the onset of lumen collapse. The peak muscle CSA occurred in close proximity with the peak pressure wave. The esophagus started to become more circular (decrease in circularity index) with the onset of the muscle CSA wave. The circularity index and muscle CSA returned to the baseline at approximately the same time. In conclusion, the onset of lumen collapse and return of circularity index of the esophagus are likely to be the true markers of the onset and end of circular muscle contraction. Circular and longitudinal muscle layers of the esophagus contract in a precise synchronous fashion during peristalsis in normal subjects.

Asynchrony between the circular and the longitudinal muscle contraction in patients with nutcracker esophagus

BACKGROUND & AIMS

The increases in intraluminal pressure and muscle cross-sectional area (CSA) during esophageal contraction are markers of circular and longitudinal muscle contractions. The goal of our study was to determine temporal synchrony between circular and longitudinal muscle contraction in healthy subjects and patients with nutcracker esophagus.

METHODS

Pressure and high-frequency intraluminal ultrasound (HFIUS) images were recorded simultaneously in healthy subjects and patients with nutcracker esophagus at 2 and 10 cm above the lower esophageal sphincter during wet swallow. HFIUS images were digitized and analyzed for the muscle CSA. The time interval (delta-t) between the peak muscle CSA and the peak pressure was determined.

RESULTS

In healthy subjects, a close temporal correlation existed between the peak contraction pressure and the peak muscle CSA with a maximum delta-t of 0.5 seconds at the 2- and 10-cm levels (0-0.5 seconds). On the other hand, the patient group had a median delta-t of 1.25 seconds (0.75-3.5 seconds) at the 2-cm level and 0.75 seconds (0-2.0 seconds) at the 10-cm level. Ninety-eight of 103 contractions in patients showed a delta-t >0.5 seconds. There was a significant correlation between delta-t and the amplitude of pressure wave, the duration of pressure wave, and the peak muscle CSA. The duration of pressure wave but not the duration of CSA wave was longer in patients with nutcracker esophagus as compared with healthy subjects.

CONCLUSIONS

Patients with nutcracker esophagus show temporal asynchrony between the contractions of circular and longitudinal muscle layers.

Remodelling of the left anterior descending artery in a porcine model of supravalvular aortic stenosis

BACKGROUND

Knowledge of the adaptive mechanisms of structure and function of coronary arteries in response to physical stress is important in human health and disease.

OBJECTIVE

To gain a better understanding of the adaptive mechanisms of morphology in the zero-stress state of the coronary arteries in a porcine model of hypertension and flow overload.

METHODS

The effects of simultaneous increases in pressure and flow were examined by studying the left anterior decending (LAD) artery in supravalvular aortic stenosis (SVAS). In this model, the pressure is uniformly increased along the length of the LAD artery trunk, whereas the increase in flow is significantly greater in the proximal than in the distal artery. The longitudinal variation of vessel dimension, medial and adventitial area, opening angle and residual strains were examined in the LAD arteries of aortic-banded (n = 5) and control (n = 5) pigs.

RESULTS

Our results show that the wall shear stress was normalized, whereas the circumferential stress was increased, in the proximal portion of the LAD artery after 5 weeks of SVAS. In the distal artery, both shear and circumferential stresses were normalized. The vessel wall area was also increased in the remodelled vessels as the result of an increase in the medial and adventitial area.

CONCLUSION

The major conclusion of this study is that, in the SVAS model, the remodelling process of the coronary artery is consistent with normalization of shear stress despite an increase in the circumferential stress. Furthermore, the remodelling of the zero-stress state is also dominated by flow overload.

A novel ultrasound technique to study the biomechanics of the human esophagus in vivo

The objectives of this study were to validate a novel ultrasound technique and to use it to study the circumferential stress-strain properties of the human esophagus in vivo. A manometric catheter equipped with a high-compliance bag and a high-frequency intraluminal ultrasonography probe was used to record esophageal pressure and images. Validation studies were performed in vitro followed by in vivo studies in healthy human subjects. Esophageal distensions were performed with either an isovolumic (5-20 ml of water) or with an isobaric (10-60 mmHg) technique. Sustained distension was also performed for 3 min in each subject. The circumferential wall stress and strain were calculated. In vitro studies indicate that the ultrasound technique can make measurements of the esophageal wall with an accuracy of 0.01 mm. The in vivo studies provide the necessary data to compute the Kirchhoff's stress, Green's strain, and Young's elastic modulus during esophageal distensions. The stress-strain relationship revealed a linear shape, the slope of which corresponds to the Young's modulus. During sustained distensions, we found dynamic changes of stress and strain during the period of distension. We describe and validate a novel ultrasound technique that allows measurement of biomechanical properties of the esophagus in vivo in humans.

Nonstenotic internal carotid arteries: effects of age and blood pressure at the time of scanning on Doppler US velocity measurements

PURPOSE

To assess the effects of age and blood pressure at the time of scanning on internal carotid artery velocities and cross-sectional diameter at Doppler ultrasonography (US).

MATERIALS AND METHODS

During 12 months, 1,020 consecutive patients underwent internal carotid artery Doppler US. No or minimal arterial disease was found in 142 patients (67 women, 75 men). Blood pressure was recorded prior to examination. The angle-corrected internal carotid artery peak systolic and end-diastolic velocities were obtained. The effects of systolic blood pressure, diastolic blood pressure, pulse pressure, age, chronic hypertension, and medications for hypertension on velocities were evaluated by using linear regression analysis.

RESULTS

Peak systolic velocity was influenced by age (P =.008), systolic blood pressure (P =.009), diastolic blood pressure (P =.003), and pulse pressure (P =.017) but not history of hypertension (P =.53) or antihypertensive medication use (P =.77). Increasing age decreased peak systolic velocity by 0.34 cm/sec/y. End-diastolic velocity was influenced by age (P <.001) but not by systolic, diastolic, or pulse pressure (all P values were >.13).

CONCLUSION

Internal carotid artery peak systolic velocities decrease with advancing age and increase with increasing pulse pressure. The effects of blood pressure at the time of scanning are small, but isolated systolic hypertension could cause increases in spurious velocity.

Effect of fluvastatin on endothelium-dependent brachial artery vasodilation in patients after renal transplantation

BACKGROUND

Hypercholesterolemia may affect both endothelial function and arterial distensibility (DC). Renal transplant recipients (NTX) exhibit advanced structural and functional alterations of arterial vessel walls. The aim of this double-blind, randomized trial was to evaluate the effects of fluvastatin (FLU) on brachial artery flow-mediated vasodilation (FMD) and DC in hypercholesterolemic NTX.

METHODS

Eighteen NTX received FLU 40 mg/day and 18 NTX placebo (PLA). Before and after six months of treatment, the brachial artery diameter and DC at rest were measured by a Doppler frequency analysis in the M mode, and then changes in diameter during reactive hyperemia (to assess endothelial-dependent FMD) and after 400 microg sublingual nitroglycerin (to assess endothelium-independent vasodilation-NMD).

RESULTS

FLU, but not PLA, treatment resulted in significant decreases in total (from 288 +/- 10 to 239 +/- 8 mg/dL, P < 0.05) and low-density lipoprotein cholesterol (from 182 +/- 779 to 138 +/- 8 mg/dL, P < 0.05). Blood pressure did not differ between FLU- and PLA-treated patients and was not affected by either treatment. Also, the brachial artery baseline diameter was not different between groups and was not affected by FLU or PLA. Brachial artery flow at rest and during reactive hyperemia as measured by pulsed Doppler did not differ between groups. Brachial artery FMD increased with FLU from 0.23 +/- 0.08 to 0.54 +/- 0.08 mm (P < 0.05), whereas PLA did not alter FMD (0.22 +/- 0.07 vs. 0.14 +/- 0.05 mm at baseline and after six months of PLA treatment, respectively, P = NS). In contrast, NMD did not change significantly with either treatment (0.76 +/- 0.13 vs. 0.83 +/- 0.15 mm at baseline and after 6 months of FLU treatment, respectively, P = NS, and 0.64 +/- 0.09 vs. 0.66 +/- 0.10 mm at baseline and after 6 months of PLA treatment, respectively, P = NS). Also, brachial artery DC was not altered by FLU (6.4 +/- 1.0 vs. 5.8 +/- 0.6 x 10-3/kPa, P = NS) or PLA treatment (5.8 +/- 0.6 vs. 6.8 +/- 0.8 x 10-3/kPa, P = NS).

CONCLUSIONS

In hypercholesterolemic NTX, the HMG-CoA reductase inhibitor FLU significantly improves brachial artery FMD as a measure of endothelial function after six months of treatment. In contrast, FLU does not have a beneficial effect on brachial artery DC.

Cross-sectional and 4-year longitudinal associations between brachial pulse pressure and common carotid intima-media thickness in a general population. The EVA study

BACKGROUND AND PURPOSE

The cross-sectional and 4-year longitudinal associations between brachial pulse pressure (PP) and ultrasound measurements of common carotid intima-media thickness (CCA-IMT) were assessed.

METHODS

A population of 957 volunteers aged 59 to 71 years was recruited from the electoral rolls of the city of Nantes (western France) and reexamined 4 years later. Longitudinal changes in PP and CCA-IMT were computed as the difference between 4-year follow-up and baseline values.

RESULTS

Baseline CCA-IMT and PP were positively associated in both age- and sex-adjusted analysis (partial correlation coefficient=0.20, P<0.001) and in multivariate analysis adjusted for traditional cardiovascular risk factors and mean blood pressure (partial correlation coefficient=0.18, P<0.001). In longitudinal analysis, baseline PP was associated with the change in 4-year CCA-IMT (partial correlation coefficient=0.11, P<0.001), and baseline CCA-IMT was a predictor of the 4-year change in PP (partial correlation coefficient=0.10, 0.001<P<0.01). No association between mean blood pressure and CCA-IMT was observed once PP was taken into account, in either cross-sectional or longitudinal analyses (partial correlation coefficients ranged from 0.00 to 0.03). Similar patterns of results were observed in hypertensive, nonhypertensive, and antihypertensive-treated and -nontreated subjects.

CONCLUSIONS

This longitudinal study of a large population of relatively aged subjects suggests that elevated levels of PP are associated with the progression of CCA-IMT, and increased CCA-IMT is associated with PP widening. The nature of these relationships and whether atherosclerosis progression over time is involved or not in these associations merit further investigations.