Large Muscular Arteries Research Articles

Optimization of pulmonary artery mechanical testing

Pulmonary arterial hypertension (PAH) is an incurable disease with mortality within 3 years in 28-55% of high-risk patients. The progression of PAH has been known to be associated with increased vascular stiffness and vascular remodeling. Recent studies have suggested that increased stiffness may in fact be a driver for some of the metabolic abnormalities observed during PAH. To gain more insights into this relationship, we need to quantify the differences in mechanical properties of healthy and hypertensive pulmonary arteries. The stress-strain relationship is the gold standard for the ex-vivo stiffness measurement of arteries. This is obtained by obtaining force vs. distension data by tensile testing and using sample dimensions, i.e. length, lumen diameter, and wall thickness, to calculate engineering stress and strain. While this approach is well-optimized for large muscular arteries, it has not been used to test pulmonary arteries as their thin walls and low basal tone make it challenging to make precise measurements of sample wall thickness and lumen diameter. Thus, the goals of this study were to: 1) establish a reliable protocol for rat pulmonary artery tensile testing and 2) quantify the differences in stiffness between hypertensive and healthy pulmonary arteries. First, a methodology to improve the fidelity of determining the lumen diameter and wall thickness was developed. Using this approach, we observed that the modulus was negatively correlated with the length of the vessel segment tested. This suggests that vessel length should be standardized to perform reliable comparisons between groups. Next, we performed tensile tensing on both control and hypertensive pulmonary arteries, after standardizing vessel segment lengths. We initially modeled this tensile testing data using a one-term exponential equation and we observed that intact hypertensive arteries were ~2.7 times stiffer than control arteries at low strain (strain = 0.8). Whereas at high strain (strain = 2.8) intact and decellularized hypertensive arteries were 20 and 29 times stiffer than control arteries respectively. To better capture the viscoelastic properties of both, the cellular and ECM components of the vessels we also fit the tensile testing data using a two-term exponential equation. Using this two-term exponential model, we observed that hypertensive vessels were 2.2 times stiffer than the controls at normal hoop stress (20 kPa), and at the hypertensive hoop stress (66 kPa) the diseased vessels showed less variability in stiffness as compared to the controls. These findings and the methods developed in this study will be helpful in conducting and analyzing experiments to investigate the relationship between changes in biomechanical signals and the progression of PAH. R01HL151530 (KS), R01HL126514 (LS). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

SEMI-AUTOMATIC MEASUREMENT OF INTIMA-MEDIA THICKNESS OF BRACHIAL ARTERY IN PATIENTS WITH CONGESTIVE HEART FAILURE

Objective: Cardiovascular diseases are associated with an increase in intima-media thickness (IMT). However, the techniques used to measure IMT have limitations. A semi-automatic device called UNEX has been developed, which overcomes the limitation of classic systems (in particular the investigator-dependency of conventional, “hand-held’’ measurements). The purpose of this study was to measure the intima-media thickness of the brachial artery (bIMT) with the UNEX device in patients with and without congestive heart failure. Design and method: The UNEX device is comprised of a 7.5-MHz, H-shaped linear array transducer and a novel stereotactic probe-holding device (UNEX EF 18G; UNEX Co., Nagoya, Japan). Another advantage of this device is the continuous recording of B-mode images and A-mode waves of the brachial artery. Measurement of bIMT was automatically performed on A-mode images of the far wall of the brachial artery. The analysis system automatically detects the measurement point where an image was clearly obtained. The average of mean measurement values obtained from 10 cardiac cycles was defined as bIMT. In a first set of clinical studies, we measured bIMT in patients with reduced left ventricular ejection fraction (HFrEF) and in patients without heart failure. Results: Patients with HFrEF (n = 85, ejection fraction: 38.3 ± 8.4 %, NT-pro-BNP: 713 ± 714.7 pg/ml) compared to patients without heart failure (n = 63) were older (66.4 ± 9.2 vs. 53.8 ± 12.6 years, p < 0.001), with more male subjects (67 vs. 40, p = 0.039). bIMT was higher in patients with HFrEF compared to the other group (0.295 ± 0.083 vs. 0.249 ± 0.083 mm, p < 0.001). After adjustment for age, gender and other cardiovascular risk factors, the result remained significant (p = 0.032). Conclusions: Our study demonstrate that IMT of large muscular arteries can be automatically (investigator independently) measured. Our data indicate an increased vascular remodeling in patients with HFrEF independent of other confounders.

Tissue Expression of TNF-alpha and IL-18 by Real Time PCR in Initiated Atherosclerosis in Wistar Male Rats

Background: Atherosclerosis is diverse disease with heterogenous mechanisms of progression and is an oxidative, chronic inflammatory and thrombotic disease produced by elevated level of low density lipoprotein cholesterol (LDL-C) in the blood. Initiation of atherosclerosis begins with the production of various inflammatory cytokines and adhesive molecules on the endothelium of the large muscular arteries like aorta. The present study was carried out to know the expression of TNF-Alpha and IL-18 by real time PCR (Polymerase chain reaction). Methods: Procured 24 Wistar albino rats and divided into two groups consisting of 12 rats in each. Atherosclerosis was induced by addition of 1% cholesterol and 15% saturated oil to the 1000g of standard rat diet and given to group II rats. Group I kept as control and maintained for 90 days. Result: Group II rats clinically showed obesity with significant increase (p less than 0.05) in the body weight. TC, TG, LDL-C, VLDL-C were significantly (p less than 0.05) higher, whereas HDL-C was significantly (p less than 0.05) reduced. Atherogenic diet induced the initiation of atherosclerosis in the aorta with degeneration of endothelial cells, sub intimal lipid laden macrophages (foam cells), slight thickening of the tunica intima with proliferation of few SMCs in group I rats. Present study revealed positive expression of TNF- alpha and no expression of IL-18 cytokine in the aorta of group II rats by RT-PCR.

Effect of golimumab on endothelial vasomotor function and arterial stiffness in ankylosing spondylitis

Objective: to evaluate the effect of golimumab (GLM) on endothelial vasomotor function and arterial stiffness in patients with ankylosing spondylitis (AS).Subjects and methods. A total of 42 patients with advanced-stage AS, who were older than 18 years and met the 1984 modified New York criteria with a disease duration of ≤5 years, were examined. The investigators visualized carotid arteries to determine local vascular wall stiffness, studied regional arterial stiffness to assess a pulse wave contour analysis, and a reactive hyperemia test before and after 104-week therapy.Results and discussion. RA patients without cardiovascular comorbidity were found to have signs of subclinical great artery involvement accompanied by endothelial vasoregulatory dysfunction in both the small resistance and large muscular arteries; by increases in common carotid artery (CCA) intima-media thickness (IMT) and stiffness index (SI); by rises in peripheral augmentation index (AIp), SI and reflection index (RI), the intensity of a change in which correlated with disease duration and activity assessed by ASDAS; as well as with the modified Schober test value, cervical rotation, and tragus-to-wall distance. In addition to a decrease in the Ankylosing Spondylitis Disease Activity Score (ASDAS), GML treatment in patients with AS caused a statistically significant increase in the amplitude occlusion index to the control values and a rise in the phase shift between the channels by an average of 2 times (p<0.01) as compared to the baseline values; a decrease in CCA IMT by an average by 20% (p=0.01) and in the local stiffness of the (carotid) vascular bed by 31% (p=0.01). The pulse wave contour analysis after 104-week GLM therapy revealed that AIp, SI and RI decreased by an average of 5 (р<0.001), 1.3 (р<0.01), and 2 (p<0.05) times, respectively, with the remaining statistically significant differences from the control values.Conclusion. In addition to the effectively reduced inflammatory activity, GLM therapy in patients with AS provides restoration of endothelial function in both the small resistance vessels (an increase in the amplitude occlusion index) and the large muscular arteries (a rise in the phase shift between the channels) and also has a vasoprotective effect on the wall of large elastic vessels (reductions in CCA IMT, SI, AIp, and SI) and small muscular arteries (a decrease in RI).

EFFECT OF GOLIMUMAB ON IMMUNOLOGICAL MARKERS FOR BONE METABOLISM AND ON ARTERIAL STIFFNESS IN PATIENTS WITH RHEUMATOID ARTHRITIS

Objective: to evaluate the effect of golimumab (GLM) on the receptor activator of NF-κB ligand (RANKL)/osteoprotegerin (OPG) transmembrane molecular system and arterial stiffness in patients with rheumatoid arthritis (RA).Subjects and methods. Thirty-six patients with RA were examined and randomized into 2 groups based on disease duration (less than or more than 2 years). The serum levels of OPG, and RANKL, were investigated. Dual-energy X-ray absorptiometry and pulse wave contour analysis were performed before and 52 weeks after GLM treatment.Results and discussion. Group 1 patients demonstrated increased serum OPG levels that were on average 3.6 times higher than in the controls (р=0.005) and 2.1 times higher than in Group 2 (р=0.01). In Group 2 patients, the RANKL concentration was 9-fold higher than that in the controls (p=0.001) and 30.6% higher than in Group 1 (p=0.01). The examinees were found to be diagnosed with subclinical damage to the great arteries (increases in augmentation index (AIp), stiffness index (SI), and reflection (RI) index), which progressed with a longer RA duration. After GLM treatment, serum OPG and RANKL levels decreased in Group 1 patients by 2.1- (p<0.001) and 1.7-fold (p<0.01), respectively. In Group 2, the level of RANKL dropped by 32.2% (p<0.01), without significant OPG concentration changes. After GLM treatment, the pulse wave contour analysis parameters in Group 1 did not differ from those in the controls; Group 2 showed significant decreases in AIp by an average of 1.8 times (p<0.01), in SI by 1.2 times (p<0.01), and in RI by 1.6 times (p<0.01).Conclusion. GLM treatment in RA patients is accompanied by a lower imbalance in the RANKL/OPG transmembrane molecular system and exerts a vasoprotective effect on the large elastic vessels (reductions in AIp and SI) and small muscular arteries (a decrease in RI).

Arterial stiffness is associated to cardiorespiratory fitness and body mass index in young Swedish adults: The Lifestyle, Biomarkers, and Atherosclerosis study

Background Early changes in the large muscular arteries are already associated with risk factors as hypertension and obesity in adolescence and young adulthood. The present study examines the association between arterial stiffness measurements, pulse wave velocity and augmentation index and lifestyle-related factors, body composition and cardiorespiratory fitness, in young, healthy, Swedish adults. Design This study used a population-based cross-sectional sample. Methods The 834 participants in the study were self-reported healthy, non-smoking, age 18-25 years. Augmentation index and pulse wave velocity were measured with applanation tonometry. Cardiorespiratory fitness was measured by ergometer bike test to estimate maximal oxygen uptake. Body mass index (kg/m2) was calculated and categorised according to classification by the World Health Organisation. Results Young Swedish adults with obesity and low cardiorespiratory fitness have significantly higher pulse wave velocity and augmentation index than non-obese young adults with medium or high cardiorespiratory fitness. The observed U-shaped association between pulse wave velocity and body mass index categories in women indicates that it might be more beneficial to be normal weight than underweight when assessing the arterial stiffness with pulse wave velocity. The highest mean pulse wave velocity was found in overweight/obese individuals with low cardiorespiratory fitness. The lowest mean pulse wave velocity was found in normal weight individuals with high cardiorespiratory fitness. Cardiorespiratory fitness had a stronger effect than body mass index on arterial stiffness in multiple regression analyses. Conclusions The inverse association between cardiorespiratory fitness and arterial stiffness is observed already in young adults. The study result highlights the importance of high cardiorespiratory fitness, but also that underweight individuals may be a possible risk group that needs to be further studied.

Does serelaxin treatment alter passive mechanical wall properties in small resistance arteries?

The peptide hormone relaxin is recognized for its connective tissue remodeling actions in the reproductive tract during pregnancy and parturition, but it also has vascular remodeling actions independent of pregnancy. Recombinant human relaxin (serelaxin) treatment in male and non-pregnant female rodents enhances passive arterial compliance in the renal vasculature. This review focuses on serelaxin's actions on passive mechanical wall properties in small arteries and highlights the diversity of responses to serelaxin treatment in rodents. Different experimental approaches (duration of serelaxin treatment, rat strain, age) and animal models of disease (obesity, hypertension) will be considered. Most studies in young rodents demonstrate that serelaxin treatment fails to alter passive compliance in resistance-size arteries (mesenteric and femoral arteries and cerebral parenchymal arterioles), suggesting that serelaxin's beneficial effects are minimal in healthy animals. Short-term serelaxin treatment (5d) in aged, obese, and spontaneously hypertensive rats (SHRs) is largely without effect on passive mechanical wall properties. However, a longer duration of serelaxin treatment in SHRs (14d) enhances passive compliance in large muscular arteries as well as resistance-size arteries. In conclusion, serelaxin is capable of vascular remodeling. Its actions are vascular bed-dependent, more prominent in disease, and likely requires a longer duration of treatment to be effective.

Изменение показателей эндотелиальной функции и жесткости артериального русла у больных ревматоидным артритом на фоне терапии лефлуномидом

The article presents the results of evaluation of leflunomide impact on endothelial function and vascular stiffness parameters in patients with rheumatoid arthritis (RA), but without cardiovascular diseases. 46 patients with RA satisfying ACR (1987) or ACR/EULAR (2010) classification criteria were examined. Investigations of endothelial function and arterial stiffness, based on the pulse wave contour analysis and the reactive hyperemia test (“AngioScan-01” device used), were conducted before the treatment and 12 months thereafter. It was determined that patients with RA suffered from subclinical damage of large arteries, characterized by endothelial dysfunction at micro- and macrocirculatory levels, and the increase in augmentation (AIp), stiffness (SI), and reflection (RI) indices, whose value correlated with RA duration, DAS28 activity index, RF level, and ACCP concentration. Leflunomide use in patients with RA was accompanied by statistically significant decrease in DAS28 index. It was shown that along with high anti-inflammatory activity leflunomide is also able of decreasing the signs of subclinical arterial damage, which is confirmed by the restoration of the endothelial function both in the system of small resistant vessels (increase in amplitude occlusion index) and large muscular arteries (increase in the value of phase shift between channels), and the decrease in stiffness of large arteries.

Lower the Low-density Lipoprotein Cholesterol to the Level When You Born

Lower the Low-density Lipoprotein Cholesterol to the Level When You Born

G486(P) First successful paediatric hla incompatible renal transplantation in the united kingdom

Aims To report the successful outcome of HLA incompatible renal transplantation using plasmapheresis and intravenous immunoglobulin (on day –1) and quadruple immunosuppression with anti–thymocyte globulin (1.5 mg/kg day 1–4), corticosteroids, mycophenolate mofetil and tacrolimus (from day -7). Methods Six month follow–up data of 14–year old young lady who underwent living related ABO compatible (O into B) and HLA incompatible renal transplantation from her father (mismatch 0,1,1) for end-stage kidney disease on peritoneal dialysis secondary to congenital abnormalities of the kidney and urinary tract with bilateral renal dysplasia, recurrent urinary tract infections, bilateral vesico–ureteric reflux after left ureteric reimplantation and right nephrectomy. She had a previous failed renal transplantation at 11 years of age with primary non–function due to intra-renal thrombosis (no acute rejection or TMA) requiring transplant nephrectomy the day after transplantation with 95–100% calculated reaction frequency due to HLA antibodies, specific for mismatches HLA B7 and DQ8 against father with B cell positive (T cell negative) crossmatch which was reduced to negative with test plasma exchange and reduction in MFI from 16,200 to 6,480 and from 11,602 to 4,625 on the day prior to transplantation. She had no offers from the deceased donor waiting list or via the paired exchange scheme (NLDKSS). Results Successful renal transplant without further antibody removal or surgical complications with six month follow–up data with stable renal allograft function with eGFR of 60–96 mls/min/1.73m 2 , 12-hour trough tacrolimus and mycophenolate levels of 7.3 mcg/l and 3.0 mg/l respectively, controlled hypertension on one anti-hypertensive agent with minimal albuminuria (17.4 mg/mmol). Her DSA reduced to 4,691on day 2 but increased further to 23,772 to 38,630 during weeks 1 to 3 and have stabilised out at 21,246 to 22,168 (B7 and DQ8 of 8,407 and 13,761 respectively). She has had three percutaneous renal transplant biopsies at weeks 2, 7 and 11 without acute rejection or IFTA but moderate concentric fibrous intimal thickening of large muscular arteries and C4d deposition in peritubular capillaries and glomeruli. Conclusions This is the first paediatric HLA incompatible renal transplantation in UK and highlights that clinicians must consider this option in ESKD patients whose living donors have been excluded due to HLA incompatibility.

The Treatment of Chronic Atherosclerotic Occlusion of the Lower Limbs – A Review of 30 Cases

Atherosclerosis affects large elastic and muscular arteries, the most commonly and severely affected being the aorta. The cerebral, coronary, and renal arteries, and the arteries of the lower limbs are also frequently involved. The principal pathological changes are intimal thickening and fibrous tissue proliferation, which cause narrowing and occlusion. Ischaemia of -tissues distal to points of obstruction occurs unless adequate collateral channels have had time to develop. Although atherosclerosis is a generalised disease, three main sites of occlusion in the lower limbs are recognised (Macpherson e t al., 1971), the aortic bifurcation (aorto-iliac disease), the superficial femoral artery (femoro-popliteal), and more distant arteries (peripheral). The purpose of this paper is to review the results of direct arterial surgery to the aorto-iliac vessels in a consecutive series of 30 patients and to correlate them with the indications for surgery and the nature of the lesions as determined by preoperative arteriography.

Extradural vascular lesion of the spine mimicking a nerve sheath tumour

Benign vascular lesions located in the spinal extradural space are rare, representing up to 4% of all spinal neoplasms. They are often misdiagnosed as nerve sheath tumours or meningiomas, based on their clinical and radiological features. In particular, only two cases of angioleiomyoma in the posterior mediastinum have ever been reported in the literature. We present the case of a 60-year-old man with a 12 month history of lower thoracic back pain radiating around the front of his ribcage to his epigastrium. MRI showed a solid, homogenous left para-spinal mass adjacent to the T11 vertebra, with no evidence of destructive changes or bony infiltration. Based on MRI, CT and FDG-PET studies this lesion was provisionally diagnosed as a benign nerve sheath tumour. He underwent successful surgical resection with remission of symptoms. Histological examination corroborated with immunohistochemis-try and special stains revealed a complex vascular lesion which, according to our knowledge has never been described before. Microscopic examination showed a circumscribed nodular lesion with vascular spaces of varying size. There were large muscular arteries with adjacent bundles of smooth muscle in the stroma. Other areas showed ectatic vascular spaces lacking a smooth muscle layer, lined by flattened endothelial cells, in myxoid stroma. These features clearly indicate the presence of an arteriovenous malformation with an extensive cavernous component, as well as a prominent angioleiomyomatous component. Besides highlighting the importance of histopathology in the diagnosis of these rare mimickers and the pitfalls of the differential diagnosis, we believe this case sheds relevant light on the hamartomatous nature of these rare and poorly understood entities.

030 Is Accelerated Atherosclerosis a Microvascular Complication of Diabetes?

Diabetes is associated with a significantly increased risk of microvascular disorders, including retinopathy, nephropathy, and neuropathy, as well as macrovascular complications, such as atherosclerosis and cardiovascular disease. Traditionally, micro- and macrovascular complications have been considered separate and distinct disorders; however, accumulating evidence suggests the two may be linked. We hypothesize that diabetes-associated accelerated atherosclerosis results from the direct effects of hyperglycemia on the vasa vasorum, the microvascular network which supplies the cells within the walls of large muscular arteries.

Vascular adaptation in athletes: is there an ‘athlete's artery’?

Whilst the existence of a specific phenotype characterized as 'athlete's heart' is generally acknowledged, the question of whether athletes exhibit characteristic vascular adaptations has not been specifically addressed. To do so in this symposium, studies which have assessed the size, wall thickness and function of elastic, large muscular and smaller resistance arteries in athletes have been reviewed. Notwithstanding the caveats pertaining to cross-sectional comparisons between athletes and 'matched' control subjects, these studies reveal increased conduit artery size, including enlargement of epicardial arteries and those supplying skeletal muscle. Evidence that peak limb blood flow responses are enhanced in athletes further suggests that resistance arteries undergo increases in total cross-sectional area. Such increases can be localized to those arteries supplying active muscle leading to speculation, supported by exercise training studies in humans and animal and cellular data, that arterial enlargement is associated with repetitive episodic increases in arterial shear stress which elicit endothelium-mediated remodelling. Such structural remodelling at conduit and resistance artery level may play a role in accommodating the substantial increase in cardiac output apparent in endurance athletes; arterial pressure is not increased at rest or during exercise in athletes (versus control subjects). Arterial wall remodelling also occurs in athletes but, in contrast to the impact of shear stress on remodelling of arterial lumenal dimensions, the impact of endurance athletic status on wall thickness may be a systemic, rather than localized, phenomenon. Finally, the question of whether the arteries of athletes exhibit enhanced function is moot. Somewhat paradoxically, measures of conduit and resistance artery endothelial function may not be enhanced, compared with healthy control subjects. This may relate to the inherent difficulty of improving arterial function which is already normal, or the time course and transient nature of functional change. It may also relate to the impact of compensatory structural remodelling, as arterial lumen size and wall thickness both affect functional responsiveness. In summary, there is clear evidence for an impact of athletic status on arterial structure and function, at least with respect to the impact of endurance training. Arterial adaptation may, to some extent, emulate that evident in the hearts of endurance athletes, and it is tempting to speculate that similar mechanisms may be at play.

Transcutaneous very-high-resolution ultrasound to quantify arterial wall layers of muscular and elastic arteries: Validation of a method

Background High-resolution ultrasound (HRU) is used to measure carotid intima-media thickness (IMT). We postulated that very-high-resolution ultrasound (VHRU, 25–55 MHz) provides more detailed information on arterial morphology. Methods Rabbit and pig arterial specimens and artificial elastin membranes were studied with HRU and VHRU, and compared to histology. Bilateral carotid, brachial, radial, ulnar, femoral, and tibial arteries were imaged in vivo in 15 humans to determine the precision of VHRU and in 53 teenagers to compare VHRU to HRU. Results The assessment of IMT, adventitia thickness (AT) and combined intima-media-adventitia thickness (IMAT) in muscular arteries was accurate and precise by VHRU with the exception that the AT of the smallest arteries was not delineated with 25 MHz. VHRU was accurate and precise for IMAT in small and for IMT in large elastic arteries and allowed to qualitatively assess elastin fibers of the media. HRU was accurate for IMT of large muscular and elastic arteries only. Intima thickness (IT) was grossly overestimated by both VHRU and HRU. Conclusion Transcutaneous VHRU provides a noninvasive method of quantifying elastic and muscular arterial AT, IMT and IMAT in children and adults, but neither VHRU nor HRU is able to assess IT in non-diseased vessels.

Effects of adrenaline on longitudinal arterial wall movements and resulting intramural shear strain: a first report

Using ultrasound we recently demonstrated that in central elastic arteries as well as in large muscular arteries in humans there is a distinct longitudinal displacement of the arterial wall during the cardiac cycle. Further, for the first time, we also demonstrated that the inner parts of the vessel wall, the intima-media complex, in these vessels exhibit a larger longitudinal displacement than the outer part of the vessel wall, the adventitial region, introducing the presence of substantial shear strain, and thus shear stress within the vessel wall. The role of these unexplored phenomena is unknown. Here, in a first study on the longitudinal movements of the porcine common carotid artery, we show that administration of adrenaline (epinephrine) might have pronounced effects on the longitudinal displacement of the intima-media complex. In this experiment the longitudinal displacement of the intima-media complex increased >200% at the highest blood pressure levels as compared to baseline. Further, shear strain within the wall increased >250%; the longitudinal displacement of the adventitial region being smaller than that of the intima-media complex. Thus, our results indicate that adrenaline can markedly influence the longitudinal displacement of the arterial wall and the resulting shear strain, and thus shear stress, within the arterial wall. This opens up a new field within cardiovascular research, revealing a previously unknown mechanism in the circulatory system. Further studies on larger materials are needed to confirm our findings and to elucidate the underlying mechanisms and the physiological, pathophysiological and clinical implications of this phenomenon.

Ageing and vascular adrenoceptor desensitization: too little, too late?

Ageing and vascular adrenoceptor desensitization: too little, too late?

Large and small artery endothelial function in patients with essential hypertension – Effect of ACE inhibition and beta‐blockade

Hypertension has been associated with changes in endothelial function in both large muscular arteries and small resistance arteries. We evaluated the relationship between blood flow velocity and dilatation of the brachial artery following transient forearm ischemia and acetylcholine‐induced relaxation in subcutaneous small arteries and the influence of antihypertensive therapy on both in patients with essential hypertension. Thirty‐one previously untreated hypertensive patients were randomized in a double‐blind fashion to treatment with either the angiotensin‐converting enzyme (ACE) inhibitor perindopril or the beta‐blocker atenolol and compared with 17 healthy normotensive controls. Before and after 1 year of treatment, while still on active medication, flow‐mediated dilatation (FMD) was measured in the brachial artery using ultrasound while relaxation to acetylcholine in small arteries was tested in vitro in a myograph. FMD correlated inversely to resting brachial artery diameter (r = −0.38, p<0.05). FMD corrected for resting diameter (FMDcorr) was lower in patients (3.0±0.2%) compared with controls (4.2±0.3%, p<0.01). In both patients and controls, FMDcorr was related to flow velocity in a non‐linear way with FMDcorr reaching a maximum despite increasing flow velocities, and in the patients, FMDcorr was only reduced at high flow velocities. Furthermore, patients had a reduced acetylcholine‐induced relaxation in small arteries (p = 0.04). Perindopril and atenolol reduced blood pressure to similar levels and both drugs improved FMDcorr to a similar degree without any effects on relaxation to acetylcholine in small arteries. The present study demonstrates the role of correcting for differences in baseline diameter during measurements of FMD and a non‐linear relationship between flow velocity and FMD in the brachial artery. Furthermore, the results suggest different effects of antihypertensive treatment on endothelial function in large and small arteries.

Modified Sleeve Anastomosis in Large Muscular Arteries of Sheep

ObjectiveThe purpose of this investigation was to test a modified telescopic anastomosis in large muscular arteries. Material and methodsThe right carotid arteries in 30 sheep (average weight 57±5.7kg) were transected and anastomosed end to end using two guided sutures and compared with a control group (10 sheeps) using two external sutures (Lauritzen method). ResultsThe mean time to complete the anastomosis (4.5min) and hemostasis (4.3min) in the experimental group was less than the control group (17.3min for anastomosis and 6.4min for hemostasis) (P<0.05). In addition, the total amount of blood loss during the modified anastomosis was significantly lower than Lauritzen method (3.8 versus 8ml). In both experimental and control groups the scanning electron microscopy (SEM) at 90th day post-operation revealed a continuous smooth layer of endothelial cells covering the anastomotic junction. ConclusionsAnastomosis with two guided sutures is easy and faster to perform and could be applicable to an acutely transected vessel.

Waist Circumference, Visceral Obesity, and Cardiovascular Risk

Waist Circumference, Visceral Obesity, and Cardiovascular Risk