Brachial Artery Doppler Research Articles

Risk factors of non-arteritic anterior ischaemic optic neuropathy and central retinal artery occlusion.

To investigate the difference in risk factors between non-arteritic anterior ischaemic optic neuropathy (NAION) and central retinal artery occlusion (CRAO) and develop a predictive diagnostic nomogram. The study included 37 patients with monocular NAION, 20 with monocular CRAO, and 24 with hypertension. Gender, age, and systemic diseases were recorded. Blood routine, lipids, hemorheology, carotid and brachial artery doppler ultrasound, and echocardiography were collected. The optic disc area, cup area, and cup-to-disc ratio (C/D) of the unaffected eye in the NAION and CRAO group and the right eye in the hypertension group were measured. The carotid artery intimal medial thickness (C-IMT) of the affected side of the CRAO group was thicker (P=0.039) and its flow-mediated dilation (FMD) was lower (P=0.049) than the NAION group. Compared with hypertension patients, NAION patients had higher whole blood reduced viscosity low-shear (WBRV-L) and erythrocyte aggregation index (EAI; P=0.045, 0.037), and CRAO patients had higher index of rigidity of erythrocyte (IR) and erythrocyte deformation index (EDI; P=0.004, 0.001). The optic cup and the C/D of the NAION group were smaller than the other two groups (P<0.0001). The diagnostic prediction model showed high diagnostic specificity (83.7%) and sensitivity (85.6%), which was highly related to hypertension, the C-IMT of the affected side, FMD, platelet (PLT), EAI, and C/D. CRAO patients show thicker C-IMT and worse endothelial function than NAION. NAION and CRAO may be related to abnormal hemorheology. A small cup and small C/D may be involved in NAION. The diagnostic nomogram can be used to preliminarily identify NAION and CRAO.

Can the change of vasomotor activity in irritable bowel syndrome patients be detected via color Doppler ultrasound?

Irritable bowel syndrome (IBS) is one of the most frequently referred conditions to the gastrointestinal outpatient clinic. The pathophysiology of IBS has not been determined with certainty. Visceral hypersensitivity is indicated as one of the pathophysiologies. The sympathetic nervous system is primarily in charge of controlling the arteries, and its effect is vasospasm in the medium and large arteries, resulting in decreased blood flow. To demonstrate, using Doppler evaluation of the brachial artery, that sympathetic activity impairs vasomotor performance due to autonomic neuropathy, which we believe is associated with IBS. There were 58 participants in the study. The control group consisted of 29 healthy patients, while the remaining 29 patients had been diagnosed with IBS. Patients who met the Rome IV criteria and had IBS were included in the study. People with known polyneuropathy or non-IBS chronic conditions that can progress were excluded from the trial, as were those with essential hypertension, diabetes mellitus, cardiovascular disease, or peripheral arterial disease, and patients diagnosed with anxiety or depression. Those with moderate to severe carpal tunnel syndrome or a median nerve lesion due to trauma were also excluded from the trial. A Doppler probe was used to measure the baseline diameter and flow rates of the brachial artery from 2 cm superior to the antecubital fossa. The Doppler probe remained stationary throughout the experiment, allowing for continuous measurements. Then, to activate the sympathetic fibers, an electrical stimulus for 5 s with an intensity of 10 mA and a frequency of 1 Hz was applied to the median nerve at the wrist level via the bipolar stimulus electrode. The artery diameter and flow rates were measured again immediately following the fifth stimulus. In healthy persons with no history of chronic illness, there was a statistically significant decrease in flow rate after stimulation (P < 0.001). In addition, stimulation resulted in a statistically significant reduction in the diameter of the brachial artery (P < 0.001). Patients diagnosed with IBS had statistically significant vasodilation and an increase in flow rate. Sympathetic stimulation causes a reduction in vascular diameter and blood flow, whereas it has the reverse effect on IBS patients. In investigating the involvement of autonomic neuropathy in the development of IBS, significant changes in brachial artery Doppler parameters were observed before and after stimulation of the median nerve with low-current sensory stimulation. This method is thought to be more user-friendly and comfortable than other methods described in the literature.

Understanding endothelial dysfunction in preterm preeclampsia with severe features: utility of bedside brachial artery Doppler

We seek to understand the mechanisms of vascular resistance and impaired vasodilatory effects in preeclampsia by studying brachial artery blood flow over time after exposure to a hyperemic stimulus. Our hypothesis is women with preeclampsia will have a decrease in flow rate from baseline over time after a hyperemic stimulus compared with controls.

603 Endothelial dysfunction is associated with hypertensive disorder during pregnancy

Abstract Aims Arterial hypertension (AH) is one of the main determinants of clinical disorders during pregnancy affecting 2% to 10% of pregnancies with a substantial public health impact. Both endothelial injury and increased vascular reactivity have been reported to be involved in the pathogenesis of pre-eclampsia syndrome. Abnormal patterns in brachial artery Doppler velocities have been shown to be predictive of pre-eclampsia in first trimester. The aim of this study is to investigate whether flow-mediated dilation (FMD) and Doppler flow derived-parameters can predict the occurrence of AH. Methods and results The study population consisted of pregnant women (mean age 32 years) who had been referred to the IRCCS Fondazione Ca’ Granda Policlinico of Milan. None of them had any medical issues and was taking any medications at the time of pregnancy. FMD was performed on left brachial artery according to expert recommendation. Measurements of brachial artery diameter and flow have been collected at rest, shortly before cuff release and then 5-, 15-, 30-, 60-, and 90-s during hyperaemia phase. Among Doppler measurements, systolic and diastolic velocity (Vs and Vd, respectively) as well as mean velocity (mean V) were considered. In addition, the pulsatility index (PI) and resistance index (RI) were calculated. A 3-months follow-up was planned in order to detect the presence of AH. All data were expressed as the median. U-test (Mann–Whitney analysis) was performed to test difference among hypertensives and non-hypertensives We recruited 48 women (median age 32 yeas) whose 4 (8.5%) developed AH during pregnancy. These latter had statistically significant higher systolic velocity measured at 5 s after the release of distal occlusion (126 cm/s vs. 173 cm/s; P &amp;lt; 0.05). No other velocity Doppler data [diastolic velocity (Vd), mean velocity (mean V), PI, RI, TAMAX, and TAMEAN] showed a statistical significant association with AH development. Conclusions The present study suggests that the vascular assessment through Doppler during FMD procedure may foresee the development of hypertensive disorder in pregnancy. Our result provides the first evidence that the peak systolic velocity of brachial artery may represent a marker of early endothelial activation or damage, that can be directly involved in the pathophysiological mechanisms of the hypertensive disorders in pregnancy.

Endothelial Dysfunction, a Marker of Atherosclerosis, Is Independent of Metabolic Syndrome in NAFLD Patients

Background The study was designed to assess cardiovascular risk factors flow-mediated dilatation % (FMD%) and carotid intima-media thickness (CIMT) in NAFLD. Methods 126 NAFLD subjects and 31 chronic hepatitis B (CHB) controls were studied. Measuring carotid intima-media thickness (CIMT) and the flow-mediated dilatation % (FMD%) by brachial artery Doppler ultrasound were used to assess atherosclerosis. The risk of cardiac events at 10 years (ROCE 10) was estimated by the Prospective Cardiovascular Munster Study (PROCAM) score. Results 58 of 126 NAFLD have coexistent metabolic syndrome. Mean CIMT was 0.73 ± 0.041 mm among NAFLD with MS, 0.66 ± 0.016 mm among NAFLD without MS, and 0.66 ± 0.037 in controls CHB patients. FMD% in NAFLD with MS was 10.43 ± 3.134%, but was 8.56 ± 3.581% in NAFLD without MS and 17.78 ± 6.051% in controls. PROCAM score of NAFLD with MS was 46.95 ± 6.509 while in NAFLD without MS was 38.2 ± 3.738. Controls had a PROCAM score of 38.13 ± 5.755. ROCE 10 in NAFLD with MS was 13.64 ± 8.568 while NAFLD without MS was 5.55 ± 1.949. Controls have a ROCE 10 of 5.95 ± 3.973. Post hoc analysis showed CIMT was dependent upon MS while FMD% was different between all subgroups hence independent of metabolic syndrome. Conclusion The markers of endothelial dysfunction are significantly higher in patients with NAFLD than controls.

Physical examination in aortic stenosis. Correlation with echocardiographic and peripheral Doppler echocardiography findings

Introduction and objectivesPhysical examination is useful for detecting cardiac murmurs in patients with suspected aortic stenosis (AS). Our aim was to evaluate the correlation between physical findings, peripheral artery Doppler, and the echocardiographic parameters of severity in patients with AS. MethodsBetween August 2017 and January 2018, patients diagnosed with AS (peak velocity >2.5m/s) were prospectively included, and classified into severe (effective orifice area [EOA] <1cm2) and non-severe AS (EOA ≥1cm2). A cardiologist, blinded to the echocardiographic findings, performed a complete physical examination, and then another cardiologist, blinded to previous data, examined the patients to evaluate interobserver variability. A brachial artery Doppler was also performed. ResultsEighty-six patients were included (mean age 76±9 years, 48% women), of which 49 (57%) had non-severe, and 37 (43%) severe AS. Murmur intensity (r=−0.32; P=.003) and duration (r=−0.54; P<.001) correlated with EOA. Absence of second heart sound was the parameter with higher AUC=0.85; P<.001), late-systole murmur duration (AUC=0.79, P<.001) and pulsus tardus ≥2 (AUC=0.77, P<.001) for severe AS. A cut-off value of 84ms in acceleration time in brachial artery had a sensitivity of 46%, specificity of 87% for severe AS. ConclusionsPhysical examination findings have an acceptable diagnostic accuracy for assessing AS severity. Prolongation of acceleration time in brachial artery could help assessing AS severity.

A prospective, longitudinal monocentric study on laser Doppler imaging of microcirculation: comparison with macrovascular pathophysiology and effect of adalimumab treatment in early rheumatoid arthritis

Increased cardiovascular (CV) morbidity and mortality have been found in rheumatoid arthritis (RA). Tumour necrosis factor α (TNF-α) inhibitors may improve vascular function. In the first part of this study, we determined microcirculation during postoocclusive reactive hyperemia (PORH) representing endothelial function. In a nonselected population (n = 46) we measured flow-mediated vasodilation (FMD) of the brachial artery and laser Doppler flow (LDF) by ultrasound. Among LDF parameters, we determined TH1 (time to half before hyperemia), TH2 (time to half after hyperemia), Tmax (time to maximum) and total hyperemic area (AH). We measured von Willebrand antigen (vWF:Ag) by ELISA. In the second part of the study, we assessed the effects of adalimumab treatment on microcirculatory parameters in 8 early RA patients at 0, 2, 4, 8 and 12 weeks. We found significant positive correlations between FMD and LDF Tmax (R = 0.456, p = 0.002), FMD and TH2 (R = 0.435, p = 0.004), and negative correlation between vWF:Ag and Tmax (R = − 0.4, p = 0.009) and between vWF:Ag and TH2 (R = − 0.446, p = 0.003). Upon adalimumab therapy in early RA, TH2 times improved in comparison to baseline (TH2baseline = 26.9 s vs. TH24weeks = 34.7 s, p = 0,032), and this effect prolonged until the end of treatment (TH28weeks = 40.5, p = 0.026; TH212weeks = 32.1, p = 0.013). After 8 weeks of treatment, significant improvement was found in AHa (AHbaseline = 1599 Perfusion Units [PU] vs. AH8weeks = 2724 PU, p = 0.045). The PORH test carried out with LDF is a sensitive option to measure endothelial dysfunction. TH1 and TH2 may be acceptable and reproducible markers. In our pilot study, treatment with adalimumab exerted favorable effects on disease activity, endothelial dysfunction and microcirculation in early RA patients.

Physical Activity in Pregnancy Is Associated with Increased Flow-mediated Dilation.

To determine the role of moderate-to-vigorous physical activity (MVPA) and sedentary behavior in flow-mediated dilation (FMD) and glucose metabolism during late pregnancy. Seventy normotensive, euglycemic pregnant women (31.6 ± 2.9 yr) in their third trimester (28-39 wk) were recruited. After a fasted blood sample; FMD was measured (brachial artery Doppler ultrasonography, normalized for the shear stimulus [area under the curve]). Anterograde and retrograde shear rate were estimated. Physical activity (MVPA) and sedentary behavior were assessed via accelerometry for seven consecutive days (Actigraph wGT3X-BT). We categorized the women as active (>150 min·wk) or inactive (<150 min·wk) according to their accelerometry data. Data were corrected for age and gestational age. On average, women were sedentary 67.1% ± 8.2% of their waking hours. Active pregnant women (>150 min·wk MVPA, n = 32) engaged in 266.7 ± 99.3 min·wk MVPA, whereas inactive pregnant women (<150 min·wk MVPA, n = 38) engaged in 76.1 ± 42.5 min·wk MVPA. The FMD response (normalized to the magnitude of shear stress stimulus) was greater in active compared with inactive pregnant women (6.5 ± 4.4 a.u. vs 3.9 ± 3.5 a.u.; F = 4.619; P = 0.005). The MVPA in active pregnant women was inversely correlated with insulin concentrations (r = -0.556; P = 0.03). In inactive pregnant women, higher amounts of sedentary behavior were associated with lower amounts of retrograde shear rate (r = 0.504; P = 0.02), retrograde blood flow (r = 0.499; P = 0.02), and retrograde velocity (r = 0.508; P = 0.02) during baseline, but not correlated with the FMD response. Engaging in MVPA during pregnancy is associated with improved FMD and a lower insulin concentration. Sedentary behavior was not associated with FMD responses.

Absence of compensatory vasodilation with perfusion pressure challenge in exercise: evidence for and implications of the noncompensator phenotype

Compromising oxygen delivery (O2D) during exercise requires compensatory vasodilatory and/or pressor responses to protect O2D:demand matching. The purpose of the study was to determine whether compensatory vasodilation is absent in some healthy young individuals in the face of a sudden reduction in exercising forearm perfusion pressure and whether this affects the exercise pressor response. Twenty-one healthy young men (21.6 ± 2.0 yr) completed rhythmic forearm exercise at a work rate equivalent to 70% of their own maximal exercise vasodilation. During steady-state exercise, the exercising arm was rapidly adjusted from below to above heart level, resulting in a reduction in forearm perfusion pressure of -30.7 ± 0.9 mmHg. Forearm blood flow (ml/min; brachial artery Doppler and echo ultrasound), mean arterial blood pressure (mmHg; finger photoplethysmography), and exercising forearm venous effluent (antecubital vein catheter) measurements revealed distinct compensatory vasodilatory differences. Thirteen individuals responded with compensatory vasodilation (509 ± 128 vs. 632 ± 136 ml·min-1·100 mmHg-1; P < 0.001), while eight individuals did not (663 ± 165 vs. 667 ± 167 ml·min-1·100 mmHg-1; P = 0.6). Compensatory pressor responses between groups were not different (5.5 ± 5.5 and 9.7 ± 9.5 mmHg; P = 0.2). Forearm blood flow, O2D, and oxygen consumption were all protected in compensators (all P > 0.05) but not in noncompensators, who therefore suffered compromises to exercise performance (6 ± 14 vs. -36 ± 29 N; P = 0.004). Phenotypic differences were not explained by potassium or nitric oxide bioavailability. In conclusion, both compensator and noncompensator vasodilator phenotype responses to a sudden compromise to exercising muscle blood flow are evident. Interindividual differences in the mechanisms governing O2D:demand matching should be considered as factors influencing exercise tolerance. NEW & NOTEWORTHY In healthy young individuals, compromising submaximally exercising muscle perfusion appears to evoke compensatory vasodilation to defend oxygen delivery. Here we report the absence of compensatory vasodilation in 8 of 21 such individuals, despite their vasodilatory capacity and increases in perfusion with increasing exercise intensity being indistinguishable from compensators. The absence of compensation impaired exercise tolerance. These findings suggest that interindividual differences in oxygen delivery:demand matching efficacy affect exercise tolerance and depend on the nature of a delivery:demand matching challenge.

Characteristics and effectiveness of vasodilatory and pressor compensation for reduced relaxation time during rhythmic forearm contractions.

What is the central question of this study? Reduced relaxation time between contractions in exercise requires increased vasodilatation and/or pressor response to prevent hypoperfusion and potential compromise to exercise tolerance. However, it remains unknown whether and to what extent local vasodilatation and/or systemic pressor compensation occurs and whether the efficacy of compensation is exercise intensity dependent. What is the main finding and its importance? We demonstrate that in a forearm exercise model vasodilatory but not pressor compensation occurs and is adequate to prevent hypoperfusion below but not above ∼40% peak work rate. Inadequate compensation occurs with exercise still well inside the submaximal domain, despite a vasodilatory reserve, and compromises exercise performance. During muscle contraction in rhythmic exercise, muscle blood flow is significantly impeded by microvascular compression. The purpose of this study was to establish the nature and magnitude of vasodilatory and/or pressor compensatory responses during forearm exercise in the face of an increased duration of mechanical microvascular compression, and whether the effectiveness of such compensation was exercise intensity dependent. Seven healthy males (21.0±1.8years old) completed progressive forearm exercise (24.5N every 3min; 2s contraction-4s relaxation duty cycle) in two conditions: control (CON), 2s 100mmHg forearm cuff inflation during contraction; and impedance (IMP), extension of cuff inflation 2s beyond contraction. Forearm blood flow (in millilitres per minute); brachial artery Doppler and echo ultrasound), mean arterial blood pressure (in millimetres of mercury; finger photoplethysmography) and exercising forearm venous effluent (antecubital vein catheter) measurements revealed an exercise intensity-dependent compensatory vasodilatation effectiveness whereby increased vasodilatation fully protected forearm blood flow up to the 30% exercise intensity in IMP. Above this exercise intensity, forearm blood flow was defended only in part, although submaximal oxygen uptake was not compromised for any completed work rate. As a result, peak exercise intensity (175±22 versus 196±28N, P=0.04) and oxygen delivery (76±14 versus 112±22mlO2 min-1 , P=0.01) were significantly reduced in IMP compared with CON. In conclusion, reducing relaxation time compromised exercise capacity without compromise to oxygen uptake. Vasodilatory compensation was complete at lower but not higher exercise intensities, whereas pressor compensation was absent. The reasons for the exercise intensity dependence of the efficacy of vasodilatory compensation remain to be determined.

The value of brachial artery peak velocity variation during the Valsalva maneuver to predict fluid responsiveness

Objective: To evaluate whether brachial artery peak velocity variation(ΔVp) during a Valsalva maneuver(VM) could predict fluid responsiveness in spontaneously breathing patients. Methods: Ninety-six patients required radial artery catheter for elective surgery of Ningbo Yinzhou People's Hospital from December 2014 to June 2016 were enrolled. The brachial artery Doppler signal was recorded to measure the ΔVp while the VM was performed.Then doing the volume expansion (VE) , the cardiac output variation (ΔCO) before and after VE were measured.Pearson correlational analyses were conducted between ΔVp and ΔCO. Also the sensitivity and specificity of ΔVp were determined in predicting fluid responsiveness by the receiver operating characteristic (ROC) curve. Results: Patients were classified as group responders (n=24) and group non-responders (n=72). Responder was defined as cardiac output increased≥15% after VE.The ΔVp correlated well with ΔCO (r=0.792, P<0.01). The area under ROC curve was 0.903, with the ΔVp cut-off of 33%, the sensitivity of 87% and the specificity of 82%(P<0.01). Conclusion: Brachial artery peak velocity variation during a valsalva maneuver is a feasible method for predicting fluid responsiveness in spontaneously breathing patients.

Discriminative role of brachial artery Doppler parameters in correlation with hemodialysis arteriovenous fistula.

PurposeThe aim of this study was to evaluate the flow volume and resistive index parameters of the brachial artery in the functioning and dysfunctioning radiocephalic and brachiocephalic hemodialysis arteriovenous fistula (AVF).Methods82 patients were distributed into three groups according to their hemodialysis function - as normal function, decreased pump flow and increased venous pressure. Flow volumes and resistive indexes (RI) of the brachial artery of radiocephalic and brachiocephalic AVFs were measured by Doppler ultrasound. Flow parameters of the groups were compared.ResultsA statistically significant difference was found between the normal and decreased pump flow groups in terms of flow volume and resistive index values. 770 ml/min flow volume of the brachial artery has a 94% sensitivity and 84% specificity and 0.52 value of RI has an 89% sensitivity and 88% specificity in the the differentiation of normal and decreased pump flow groups.ConclusionDoppler parameters of the brachial artery such as flow volume and RI can provide valuable information about AVF function.

Brachial artery Doppler flux parameters before and after hot flush in Mexican postmenopausal women: preliminary report.

ObjectiveTo analyse brachial artery flux parameters in postmenopausal women before and after hot flush.Material and methodsTwo groups of postmenopausal women were studied: Group I, without vasomotor symptoms (n = 10) and Group II, with vasomotor symptoms (n = 10). In all them a brachial artery Doppler ultrasound was done, measuring before and after hyperaemic stimulus of the arterial diameter (AD), the pulsatility index (PI), and the resistive index (RI). In Group I, measurements were done at baseline and five minutes after. In Group II, measurements were at baseline, and one and five minutes after the hot-flush. Comparison between the groups was done with Mann-Whitney U test, and within the groups with Wilcoxon test.ResultsNo differences were found among the groups in Doppler parameters. When comparing each group separately, in Group I, at baseline and at five minutes measurements, the AD was greater after the hyperaemic stimulus than before it. In group II at baseline, the PI was significantly greater after the hyperaemic stimulus than before to it. At the first and fifth minute, the AD was significantly greater after the hyperaemic stimulus than before to it.ConclusionsNo differences were found between those who did not have and those who had hot flushes.

Сравнительная оценка влияния изосорбида динитрата, изосорбида-5-мононитрата и никорандила на частоту приступов стенокардии и вазорегулирующую функцию эндотелия у больных ишемической болезнью сердца

to compare effects of isosorbide dinitrate, isosorbide-5-mononitrate and nicorandil on frequency of angina attacks and vasoregulating endothelial function in patients with ischemic heart disease (IHD). MATERIAL AND METHODS. In 117 patients with stable II-III functional class angina we analyzed frequency of angina attacks, exercise tolerance, data of 24-hour Holter ECG monitoring and brachial artery Doppler study. RESULTS. Patients with IHD had impaired endothelium-dependent vasodilation in the form of reduced endothelial response to increase of "shear stress" during test with reactive hyperemia. Long-term therapy with isosorbide dinitrate, isosorbide-5-mononitrate, and nicorandil was associated with normalization of endothelium-dependent vasodilation of the brachial artery. This effect was more pronounced during therapy with nicorandil.

Relation of skinfold thickness and visceral fat with the endothelial function in Mexican postmenopausal women.

ObjectiveTo determine the relationship between skinfolds and visceral fat with vascular reactivity according to body weight, fat distribution and time since menopause in Mexican postmenopausal women.Material and methodsIn postmenopausal women, tricipital, suprailiac and subscapular skinfolds as well as blood pressure were measured, and body mass index (BMI) and waist-hip ratio (WHR) were calculated. Brachial artery Doppler ultrasound at baseline and after the hyperemic stimulus was done and Doppler parameters were assessed. For statistical analysis, Pearson and Spearman correlation analysis, as well as Student t were used.ResultsSixty-six postmenopausal women were studied; age was 54.5 ± 7.4 years. Skinfold thickness was related with subcutaneous and visceral fat. In all groups, the arterial diameter increased after the hyperemic stimulus among 6.5% and 9% of women. The pulsatility index decreased in the whole group and in those with BMI ≤ 27, WHR ≤ 0.85 and time since menopause ≤ 10 years. Negative correlations were observed between the percentage of change in arterial dilatation and the subscapular skinfold and subcutaneous fat in the whole group and in the subgroups with BMI > 27 and WHR > 0.85.ConclusionsSkinfolds are indirectly related with visceral fat, and skinfold thickness permit to conclude about impact in endothelial environment.

Individual susceptibility to hypoperfusion and reductions in exercise performance when perfusion pressure is reduced: evidence for vasodilator phenotypes.

The primary objective of this study was to determine whether cardiovascular compensatory response phenotypes exist in the face of a reduced perfusion pressure challenge to exercising muscle oxygen delivery (O2D), and whether these responses might be exercise intensity (EI) dependent. Ten healthy men (19.5 ± 0.4 yr) completed two trials of progressive forearm isometric handgrip exercise to exhaustion (24.5 N increments every 3.5 min) in each of forearm above and below heart level [forearm arterial perfusion pressure (FAPP) difference of 29.5 ± 0.97 mmHg]. At the end of each EI, measurements of forearm blood flow (FBF; ml/min) via brachial artery Doppler and echo ultrasound, mean arterial blood pressure (MAP; mmHg) via finger photoplethysmography, and exercising forearm venous effluent via antecubital vein catheter revealed distinct cardiovascular response groups: n = 6 with compensatory vasodilation vs. n = 4 without compensatory vasodilation. Compensatory vasodilators were able to blunt the perfusion pressure-evoked reduction in submaximal O2D in the arm-above-heart condition, whereas nonvasodilators did not (-22.5 ± 13.6 vs. -65.4 ± 14.1 ml O2/min; P < 0.05), and in combination with being able to increase O2 extraction, nonvasodilators defended submaximal V̇o2 and experienced less of an accumulated submaximal O2D deficit (-80.7 ± 24.7 vs. -219.1 ± 36.0 ml O2/min; P < 0.05). As a result, the compensatory vasodilators experienced less of a compromise to peak EI than nonvasodilators (-24.5 ± 3.5 N vs. -52.1 ± 8.9 N; P < 0.05). In conclusion, in the forearm exercise model studied, vasodilatory response phenotypes exist that determine individual susceptibility to hypoperfusion and the degree to which aerobic metabolism and exercise performance are compromised.

A comparison of Doppler waveform parameters versus flow-mediated vascular dilation of the brachial artery in pregnant women.

Flow mediated dilation of the brachial artery is impaired with endothelial dysfunction. We previously identified that brachial artery waveforms were changed in preeclamptic women. We therefore sought to compare Doppler waveform analysis with flow mediated vascular dilation (FMVD) measurements in pregnant women. A cross sectional study of 71 pregnant women at >20weeks gestation comparing FMVD measurements with Doppler waveform parameters was performed. Research was conducted at three hospitals and two geographic settings; (1) Yale-New Haven Hospital in New Haven, CT, (2) Mount Hope Maternity and (3) Port of Spain General Hospital in Trinidad. Brachial artery Doppler waveform measurements were done at baseline and 90s post cuff-release. From the Doppler waveforms we assessed percent change in Peak Systolic Velocity (% ΔPSV), systolic acceleration, acceleration time and pulsatility index and compared them with the percent change in FMVD. Statistical analysis using Student's t tests and correlation coefficient was done as necessary. Correlation analysis between the % change in the Doppler waveform parameters and the % change in mean FMVD identified only the waveform parameter of % ΔPSV as significantly correlated (p=0.040). FMVD remains the gold standard for assessment of endothelial dysfunction. A correlation was observed between the Doppler measured % ΔPSV and FMVD, which may allow it to be used to assess endothelial dysfunction changes under different conditions was identified.

Impaired endothelial function in patients with Takayasu’s arteritis

Objectives Takayasu’s arteritis (TAK) is a chronic, inflammatory, large-vessel vasculitis. In this study we aimed to evaluate vascular endothelial function by brachial ultrasonography and to evaluate carotid artery intima-media thickness (CIMT) in patients with TAK compared to systemic lupus erythematosus (SLE) and healthy controls.Methods The study included 32 patients with TAK, fulfilling the 1990 Classification Criteria of American College of Rheumatology (ACR), 18 patients with systemic lupus erythematosus (SLE) classified according to the 1982 ACR Criteria and 20 age- and sex-matched controls. Brachial artery Doppler ultrasonography and bilateral CIMT measurements were performed.Results Basal diameter and nitrate-induced dilatation (NID) values of the brachial artery were similar between the three groups. Flow-mediated dilation (FMD) was markedly reduced in patients with TAK compared to controls (P = 0.0001). CIMT was also signifi cantly increased in the TAK group, compared to the controls (P = 0.0001). In the SLE group, a marked impairment in FMD% was also obtained compared to controls (P = 0.0001). CIMT measurement was similar between the patients with SLE and the controls (P = 0.60, P= 0.05).Conclusions We detected significantly decreased FMD and increased CIMT in TAK, suggesting a marked endothelial dysfunction. Both chronic systemic inflammation and vasculitis might lead to endothelial dysfunction and increased atherosclerosis in TAK, suggesting that management of cardiovascular risk factors are also important in the management of vasculitis.

Association of mitral annular calcification with endothelial dysfunction, carotid intima-media thickness and serum fetuin-A: an observational study

Mitral annular calcification (MAC) is characterized by degenerative calcification of the mitral valve annulus. Atherosclerosis plays role in progression of MAC. Fetuin A is the inhibitor of pathological calcification. In the present study, we investigated the relationship between MAC and fetuin A with carotid intima media thickness (CIMT) and endothelial dysfunction. In this observational cross-sectional study, 40 patients with documented MAC on transthoracic echocardiography and 40 without MAC were included. All patients had coronary artery disease (CAD). Endothelial functions were assessed by brachial artery Doppler ultrasound (USG) and carotid artery Doppler USG. Serum fetuin-A level was also measured. Linear regression analysis and receiver operator curve analysis were performed. Endothelial derived vasodilatory response (EDVR) was significantly decreased and CIMT value was increased in MAC group. There was a strong positive correlation between EDVR and serum fetuin-A value. There was a strong negative correlation between CIMT and EDVR, moderately negative correlation between CIMT and serum fetuin-A level. Simple linear regression analysis revealed that CIMT (β=0.367, p=0.001) and serum fetuin-A level (β=-0.291, p=0.009) were independent factors associated with MAC. The area under the curve (AUC) for serum fetuin-A level was 0.731 (95% 0.620-0.824) and AUC for CIMT was 0.724 (95% CI 0.613-0.818). We observed that MAC is closely related with CIMT and serum fetuin-A level. Serum fetuin-A and CIMT can be used as independent markers in the diagnosis of MAC. We suggest that MAC can be used as an early determinant of CAD.

Upper extremity hemodynamics and sensation with backpack loads

Heavy backpacks are often used in extreme environments, for example by military during combat, therefore completion of tasks quickly and efficiently is of operational relevance. The purpose of this study was to quantify hemodynamic parameters (brachial artery Doppler and microvascular flow by photoplethysmography; tissue oxygenation by near-infrared spectroscopy; arterial oxygen saturation by pulse oximeter) and sensation in upper extremities and hands (Semmes-Weinstein monofilament test and 2-point discrimination test) while wearing a loaded backpack (12 kg) in healthy adults for 10 min. All values were compared to baseline before wearing a backpack. Moderate weight loaded backpack loads significantly decreased upper extremity sensation as well as all macrovascular and microvascular hemodynamic values. Decreased macrovascular and microvascular hemodynamics may produce neurological dysfunction and consequently, probably affect fine motor control of the hands.