Common Femoral Artery Blood Flow Research Articles

Ultrasound vector mapping of common femoral artery blood flow in normal and early-stage stenosis

It is assumed that the wall shear stress (WSS), which determines the function of the endothelium, is constant along the arterial bed. The assessment of turbulence, blood flow velocity in the arterial system in healthy (13 patients) and in patients with the initial form of atherosclerosis in the femoral artery (42 patients) was discussed. The study quantified blood flow in the common femoral artery using V Flow with visualization of blood flow with a high frame rate. The results obtained in the femoral arteries were evaluated by the wall shear rate, velocity profile and oscillation index (OSI). It was shown that the average value of WSSmean in the femoral artery in healthy and in patients with stenosis <30–35% is 0.9± 0.4 – 0.91±0.4 Pa and does not significantly differ. The wall thickness in the common femoral artery in patients with the initial form of atherosclerosis was 0.9–1.1 mm, and in healthy patients 0.8–0.9 mm. The correlation between the parameters was evaluated by nonparametric analysis of Kendall’s Taub. It was revealed that there is no correlation between WSSmean and blood flow velocity (Vs) in both healthy and patients with the initial form of atherosclerosis.

Thermo-haemodynamic coupling during regional thigh heating: Insight into the importance of local thermosensitive mechanisms in blood circulation.

A positive relationship between local tissue temperature and perfusion exists, with isolated limb-segment hyperthermia stimulating hyperaemia in the heated region without affecting the adjacent, non-heated limb segment. However, whether partial-limb segment heating evokes a heightened tissue perfusion in the heated region without directly or reflexly affecting the non-heated tissues of the same limb segment remains unknown. This study investigated, in 11 healthy young adults, the lower limb temperature and haemodynamic responses to three levels of 1h upper-leg heating, none of which alter core temperature: (1) whole-thigh (WTH; water-perfused garment), (2) quadriceps (QH; water-perfused garment) and (3) partial-quadriceps (PQH; pulsed shortwave diathermy) heating. It was hypothesised that perfusion would only increase in the heated regions. WTH, QH and PQH increased local heated tissue temperature by 2.9±0.6, 2.0±0.7 and 2.9±1.3°C (P<0.0001), respectively, whilst remaining unchanged in the non-heated hamstrings and quadriceps tissues during QH and PQH. WTH induced a two-fold increase in common femoral artery blood flow (P<0.0001) whereas QH and PQH evoked a similar ∼1.4-fold elevation (P≤0.0018). During QH and PQH, however, tissue oxygen saturation and laser-Doppler skin blood flow in the adjacent non-heated hamstrings or quadriceps tissues remained stable (P>0.5000). These findings in healthy young humans demonstrate a tight thermo-haemodynamic coupling during regional thigh heating, providing further evidence of the importance of local heat-activated mechanisms on the control of blood circulation.

Sympathetic Transduction at Rest and During Cold Pressor Test in Young Healthy non-Hispanic Black and White Women.

Non-Hispanic Black (BL) individuals have the highest prevalence of hypertension and cardiovascular disease (CVD) compared to all other racial/ethnic groups. Previous work focused on racial disparities in sympathetic control and blood pressure (BP) regulation between young BL and White (WH) adults, have mainly included men. Herein, we hypothesized that BL women would exhibit augmented resting sympathetic vascular transduction and greater sympathetic and BP reactivity to cold pressor test (CPT) compared to WH women. Twenty-eight young healthy women (BL:n=14, 224 years; WH:n=14, 224 years) participated. Beat-to-beat BP (Finometer), common femoral artery blood flow (duplex Doppler ultrasound), and muscle sympathetic nerve activity (MSNA; microneurography) were continuously recorded. In a subset (BL n=10, WH n=11), MSNA and BP were recorded at rest and during a two-minute CPT. Resting sympathetic vascular transduction was quantified as changes in leg vascular conductance (LVC) and mean arterial pressure (MAP) following spontaneous bursts of MSNA using signal-averaging. Sympathetic and BP reactivity was quantified as changes in MSNA and MAP during the last minute of CPT. There were no differences in nadir LVC following resting MSNA bursts between BL (-8.74±3.45%) and WH women (-7.48±3.52%; P=0.431). Likewise, peak increases in MAP following MSNA bursts were not different between groups (BL:+2.80+1.4mmHg; vs. WH: +3.02±1.2mmHg; P=0.623). During CPT, increases in MSNA and MAP were also not different between BL and WH women, with similar transduction estimates between groups (ΔMAP/ΔMSNA; P=0.182). These findings indicate that young, healthy BL women do not exhibit exaggerated sympathetic transduction or augmented sympathetic and BP reactivity during CPT.

Twelve-Week Daily Gluteal and Hamstring Electrical Stimulation Improves Vascular Structure and Function, Limb Volume, and Sitting Pressure in Spinal Cord Injury: A Pilot Feasibility Study.

We examined the long-term effects of low-intensity electrical stimulation on (micro)vasculature and sitting pressure of a home-based, wearable electrical stimulation device in a pilot feasibility study. In a cohort observation before-after trial, nine middle-aged male (n = 8) and female (n = 1) individuals (48 ± 15 yrs) with American Spinal Injury Association A-C classified chronic (1-24 yrs) spinal cord injury underwent 12 wks of self-administered daily, low-intensity gluteal and hamstring electrical stimulation (50 Hz, 6 hrs [30-min electrical stimulation, 15-min rest]). Common femoral artery diameter and blood blow were determined with ultrasound, skin vascular function during local heating was assessed using Laser-Doppler flowmetry, thigh volume was estimated using leg circumferences and skinfolds, and interface sitting pressure was measured using pressure mapping. Resting common femoral artery diameter increased (0.73 ± 0.20 to 0.79 ± 0.22 cm, P < 0.001) and baseline common femoral artery blood flow increased (0.28 ± 0.12 to 0.40 ± 0.15 l/min, P < 0.002). Gluteal cutaneous vascular conductance showed a time*temperature interaction (P = 0.01) with higher conductance at 42°C after 12 wks. Ischial peak pressure decreased (P = 0.003) by 32 ± 23 mm Hg and pressure gradient decreased (23 ± 7 to 16 ± 6 mm Hg, P = 0.007). Thigh volume increased (+19%, P = 0.01). Twelve-week daily home-based gluteal and hamstring electrical stimulation is feasible and effective to improve (micro)vasculature and sitting pressure, and electrical stimulation may have clinical implications for ameliorating pressure ulcers and (micro)vascular complications in spinal cord injury.

Passive leg movement: A novel method to assess vascular function during passive leg heating?

Passive leg movement: A novel method to assess vascular function during passive leg heating?

Intra-rater reliability of leg blood flow during dynamic exercise using Doppler ultrasound.

Developing an exercise model that resembles a traditional form of aerobic exercise and facilitates a complete simultaneous assessment of multiple parameters within the oxygen cascade is critically for understanding exercise intolerances in diseased populations. Measurement of muscle blood flow is a crucial component of such a model and previous studies have used invasive procedures to determine blood flow kinetics; however, this may not be appropriate in certain populations. Furthermore, current models utilizing Doppler ultrasound use isolated limb exercise and while these studies have provided useful data, the exercise model does not mimic the whole‐body physiological response to continuous dynamic exercise. Therefore, we aimed to measure common femoral artery blood flow using Doppler ultrasound during continuous dynamic stepping exercise performed at three independent workloads to assess the within day and between‐day reliability for such an exercise modality. We report a within‐session coefficient of variation of 5.8% from three combined workloads and a between‐day coefficient of variation of 12.7%. These values demonstrate acceptable measurement accuracy and support our intention of utilizing this noninvasive exercise model for an integrative assessment of the whole‐body physiological response to exercise in a range of populations.

Peripheral And Cerebral Vascular Function With Advancing Age: Evidence Of A Link

Peripheral vascular dysfunction has been documented to progress with advancing age, and age itself is the greatest risk factor for developing dementia. However, the likely link between peripheral and cerebral vascular function with aging has yet to be clearly investigated. PURPOSE: Therefore, the purpose of this study was to assess peripheral and cerebral vascular function in both young and old healthy adults and examine the relationship between the responsiveness of these vascular beds. METHODS: Peripheral vascular function was assessed with passive leg movement (PLM: blood flow ∆ peak and AUC), and cerebral vascular function was assessed by the breath hold acceleration index (BHAI) in 11 healthy adult males (7 old: 68±3 yr; 4 young: 23±3 yr). Doppler ultrasound was used to measure both common femoral artery blood flow and middle cerebral artery velocity. RESULTS: Peripheral vascular function was significantly attenuated in the old adults compared to the young (PLM AUC: 116±83 vs. 424±118 ml, p=0.001; PLM ∆ peak: 378±124 vs. 950±64 ml/min, p<0.001). Cerebral vascular function tended to be lower in the old compared to the young with a large effect size (BHAI: 1.36 ±67 vs. 2.4±1.4; d=0.95, p=0.132). However, even with a relatively limited sample size, there was a significant positive relationship between PLM AUC and BHAI (r=0.65, p=0.03). CONCLUSIONS: The identification of a relationship between the function of the peripheral and cerebral vascular beds (leg and brain) is an important step toward a better understanding of the global mechanisms of aging on the vasculature and likely age-related dementia.

Attenuated Leg Vascular Conductance Responses To Dynamic Knee Extension Exercise In Young Black Men

Our group recently showed a blunted increase in skeletal muscle vascular conductance and blood flow during rhythmic handgrip exercise in young black (i.e. African American) individuals with no overt cardiovascular diseases compared with white (i.e. Caucasian American) individuals. These findings, along with reduced endothelium‐dependent forearm vasodilation and augmented forearm vasoconstriction to phenylephrine at rest, suggest that vascular alterations occur early in the lifetime of black individuals, possibly predisposing this population to develop cardiovascular diseases. Notably, research on racial differences in vascular responses has almost exclusively examined upper limbs. However, lower limb vascular diseases are more prevalent and cause more adverse events in the black population than in any other racial group in the U.S. Therefore, for a better understanding of racial differences in vascular health, we tested the hypothesis that vascular responses to lower limb exercise would be attenuated in black individuals compared with their white counterparts. Six black (21 ± 1 years; 23 ± 2 kg/m2) and 4 white (21 ± 0 years; 21 ± 1 kg/m2) healthy men performed dynamic knee extension exercise at the workloads of 10, 20, and 30 watts (W) in an upright sitting position on a custom ergometer. Each exercise trial lasted for 3 min with a minimum rest interval of 5 min. Knee extension cadence was 50 repetitions per min, provided by a metronome and real‐time visual feedback. Common femoral artery blood flow (FABF, Doppler ultrasound) and mean arterial pressure (MAP, finger photoplethysmography) were continuously measured, and leg vascular conductance (LVC) was calculated as FABF/MAP. The participants reported a rating of perceived exertion (Borg Scale 6 – 20) at the end of each trial. Both groups presented LVC increases from rest during dynamic knee extension. While this response was similar between groups at 10 W (White: +1970 ± 138 vs. Black: +1666 ± 173 mL/min/100 mmHg; P = 0.407), the increases in LVC were significantly attenuated in black individuals (mixed‐model ANOVA interaction P = 0.026) at the workloads of 20 W (Whites: +2550 ± 105 vs. Blacks: +1829 ± 179 mL/min/100 mmHg; P = 0.025) and 30 W (Whites: +2528 ± 248 vs. Blacks: +1850 ± 152 mL/min/100 mmHg; P = 0.035). Similarly, FABF responses to dynamic knee extension were lower in black individuals compared with their white counterparts (Interaction P = 0.011). In contrast, increases in MAP were similar between groups (Interaction P = 0.271). The groups reported similar ratings of perceived exertion among trials (Interaction P = 0.817) and achieved similar peak workloads in a dynamic knee extension maximal exercise test (Whites: 48 ± 8 W vs. Blacks: 49 ± 3 W; P = 0.883). These preliminary findings suggest a blunted vasodilator response during leg exercise in black men, further highlighting the early occurrence of vascular alterations in this population.Support or Funding InformationUTA Center of Research and Scholarship Pilot Grant;NIH (1R15HL130906‐01)

Short-term water deprivation does not increase blood pressure variability or impair neurovascular function in healthy young adults.

High dietary salt increases arterial blood pressure variability (BPV) in salt-resistant, normotensive rodents and is thought to result from elevated plasma [Na+] sensitizing central sympathetic networks. Our purpose was to test the hypothesis that water deprivation (WD)-induced elevations in serum [Na+] augment BPV via changes in baroreflex function and sympathetic vascular transduction in humans. In a randomized crossover fashion, 35 adults [17 female/18 male, age: 25 ± 4 yr, systolic/diastolic blood pressure (BP): 107 ± 11/60 ± 7 mmHg, body mass index: 23 ± 3 kg/m2] completed two hydration protocols: a euhydration control condition (CON) and a stepwise reduction in water intake over 3 days, concluding with 16 h of WD. We assessed blood and urine electrolyte concentrations and osmolality, resting muscle sympathetic nerve activity (MSNA; peroneal microneurography; 18 paired recordings), beat-to-beat BP (photoplethysmography), common femoral artery blood flow (Doppler ultrasound), and heart rate (single-lead ECG). A subset of participants (n = 25) underwent ambulatory BP monitoring during day 3 of each protocol. We calculated average real variability as an index of BPV. WD increased serum [Na+] (141.0 ± 2.3 vs. 142.1 ± 1.7 mmol/L, P < 0.01) and plasma osmolality (288 ± 4 vs. 292 ± 5 mosmol/kg H2O, P < 0.01). However, WD did not increase beat-to-beat (1.9 ± 0.4 vs. 1.8 ± 0.4 mmHg, P = 0.24) or ambulatory daytime (9.6 ± 2.1 vs. 9.4 ± 3.3 mmHg, P = 0.76) systolic BPV. Additionally, sympathetic baroreflex sensitivity (P = 0.20) and sympathetic vascular transduction were not different after WD (P = 0.17 for peak Δmean BP following spontaneous MSNA bursts). These findings suggest that, despite modestly increasing serum [Na+], WD does not affect BPV, arterial baroreflex function, or sympathetic vascular transduction in healthy young adults.

Pharmacological attenuation of group III/IV muscle afferents improves endurance performance when oxygen delivery to locomotor muscles is preserved.

We sought to investigate the role of group III/IV muscle afferents in limiting endurance exercise performance, independently of their role in optimizing locomotor muscle O2 delivery. While breathing 100% O2 to ensure a similar arterial O2 content ([Formula: see text]) in both trials, eight male cyclists performed 5-km time trials under control conditions (HCTRL) and with lumbar intrathecal fentanyl (HFENT) impairing neural feedback from the lower limbs. After each time trial, common femoral artery blood flow (FBF) was quantified (Doppler ultrasound) during constant-load cycling performed at the average power of the preceding time trial. The assessment of end-tidal gases, hemoglobin content and saturation, and FBF facilitated the calculation of leg O2 delivery. Locomotor muscle activation during cycling was estimated from vastus lateralis EMG. With electrical femoral nerve stimulation, peripheral and central fatigue were quantified by pre- to postexercise decreases in quadriceps twitch torque (ΔQtw) and voluntary activation (ΔVA), respectively. FBF (~16 mL·min-1·W-1; P = 0.6), [Formula: see text] (~24 mL O2/dL; P = 0.9), and leg O2 delivery (~0.38 mL O2·min-1·W-1; P = 0.9) were not different during HCTRL and HFENT. Mean power output and time to completion were significantly improved by 9% (~310 W vs. ~288 W) and 3% (~479 s vs. ~463 s), respectively, during HFENT compared with HCTRL. Quadriceps muscle activation was 9 ± 7% higher during HFENT compared with HCTRL (P < 0.05). ΔQtw was significantly greater in HFENT compared with HCTRL (54 ± 8% vs. 39 ± 9%), whereas ΔVA was not different (~5%; P = 0.3) in both trials. These findings reveal that group III/IV muscle afferent feedback limits whole body endurance exercise performance and peripheral fatigue by restricting neural activation of locomotor muscle.NEW & NOTEWORTHY Group III/IV muscle afferent feedback facilitates endurance performance by optimizing locomotor muscle O2 delivery but also limits performance by restricting neural drive to locomotor muscle. To isolate the performance-limiting effect of these sensory neurons, we pharmacologically attenuated their central projection during a cycling time trial while controlling for locomotor muscle O2 delivery. With no difference in leg O2 delivery, afferent blockade attenuated the centrally mediated restriction in motoneuronal output and improved cycling performance.

Carotid and femoral Doppler do not allow the assessment of passive leg raising effects

BackgroundThe hemodynamic effects of the passive leg raising (PLR) test must be assessed through a direct measurement of cardiac index (CI). We tested whether changes in Doppler common carotid blood flow (CBF) and common femoral artery blood flow (FBF) could detect a positive PLR test (increase in CI ≥ 10%). We also tested whether CBF and FBF changes could track simultaneous changes in CI during PLR and volume expansion. In 51 cases, we measured CI (PiCCO2), CBF and FBF before and during a PLR test (one performed for CBF and another for FBF measurements) and before and after volume expansion, which was performed if PLR was positive.ResultsDue to poor echogenicity or insufficient Doppler signal quality, CBF could be measured in 39 cases and FBF in only 14 cases. A positive PLR response could not be detected by changes in CBF, FBF, carotid nor by femoral peak systolic velocities (areas under the receiver operating characteristic curves: 0.58 ± 0.10, 0.57 ± 0.16, 0.56 ± 0.09 and 0.64 ± 10, respectively, all not different from 0.50). The correlations between simultaneous changes in CI and CBF and in CI and FBF during PLR and volume expansion were not significant (p = 0.41 and p = 0.27, respectively).ConclusionDoppler measurements of CBF and of FBF, as well as measurements of their peak velocities, are not reliable to assess cardiac output and its changes.

P032: Twelve angry medics: a study of bimanual external aortic compression in healthy adult men

Introduction: Following life-threatening hemorrhage the goal is to temporize blood-loss and expedite definitive-rescue. Junctional (abdominal-pelvic) trauma, between the inguinal ligament and umbilicus; is a leading cause of potentially survivable mortality. Numerous devices such as junctional tourniquets and resuscitative endovascular balloon occlusion of the aorta have been suggested for this injury pattern, but we propose an immediately available and expedient bimanual maneuver that may act as a bridge to device application, proximal external aortic compression (PEAC). Of note, external aortic compression has been used for centuries in life-threatening postpartum hemorrhage. Methods: Twelve paramedic volunteers were recruited from a continuing education event. Participant demographics, blood pressure, abdominal circumference, body mass index and procedural discomfort were recorded. In pairs, six participants were taught PEAC and performed the maneuver, then exchanged roles. Training consisted of researcher led demonstration and participant return demonstration with feedback. The duration of training was less than five minutes for all participants. Femoral artery hemostasis was measured by doppler ultrasound. Results: Participant mean age was 28.6 (range 22 to 46) and their mean systolic blood pressure was 128.25 mmHg (range 102 to 145). Mean body mass index was 24 (range 22 to 28) and abdominal girth was 80 cm (range 70 to 110). Bilateral common femoral artery blood flow became undetectable in all participants, by doppler ultrasound. Participant discomfort was reported as a mean of 4.4 (range 3 to 6) on a zero to ten scale. No complications were reported with seven and 30 days follow-up. Conclusion: This study demonstrates successful PEAC in twelve healthy participants. However, our limitations include a small sample and the relatively modest abdominal circumferences of our participants. If light of these limitations, PEAC may be a potentially life-saving maneuver which is immediately deployable and easy to learn, for patient temporization until device application and/or operative rescue.

Changes in whole tissue heme concentration dissociates muscle deoxygenation from muscle oxygen extraction during passive head-up tilt.

Skeletal muscle deoxygenated hemoglobin and myoglobin concentration ([HHb]), assessed by near-infrared spectroscopy (NIRS), is commonly used as a surrogate of regional O2 extraction (reflecting the O2 delivery-to-consumption ratio, Q̇/V̇o2). However, [HHb] change (Δ[HHb]) is also influenced by capillary-venous heme concentration, and/or small blood vessel volume (reflected in total heme; [THb]). We tested the hypotheses that Δ[HHb] is associated with O2 extraction, and insensitive to [THb], over a wide range of Q̇/V̇o2 elicited by passive head-up tilt (HUT; 10-min, 15° increments, between -10° and 75°). Steady-state common femoral artery blood flow (FBF) was measured by echo-Doppler, and time-resolved NIRS measured [HHb] and [THb] of vastus lateralis (VL) and gastrocnemius (GS) in 13 men. EMG confirmed muscles were inactive. During HUT in VL [HHb] increased linearly (57 ± 10 to 101 ± 16 μM; P < 0.05 above 15°) and was associated (r(2) ∼ 0.80) with the reduction in FBF (618 ± 75 ml/min at 0° to 268 ± 52 ml/min at 75°; P < 0.05 above 30°) and the increase in [THb] (228 ± 30 vs. 252 ± 32 μM; P < 0.05 above 15°). GS response was qualitatively similar to VL. However, there was wide variation within and among individuals, such that the overall limits of agreement between Δ[HHb] and ΔFBF ranged from -35 to +19% across both muscles. Neither knowledge of tissue O2 saturation nor vascular compliance could appropriately account for the Δ[HHb]-ΔFBF dissociation. Thus, under passive tilt, [HHb] is influenced by Q̇/V̇o2, as well as microvascular hematocrit and/or tissue blood vessel volume, complicating its use as a noninvasive surrogate for muscle microvascular O2 extraction.

Spontaneous bursts of muscle sympathetic nerve activity decrease leg vascular conductance in resting humans

Previous studies in humans attempting to assess sympathetic vascular transduction have related large reflex-mediated increases in muscle sympathetic nerve activity (MSNA) to associated changes in limb vascular resistance. However, such procedures do not provide insight into the ability of MSNA to dynamically control vascular tone on a beat-by-beat basis. Thus we examined the influence of spontaneous MSNA bursts on leg vascular conductance (LVC) and how variations in MSNA burst pattern (single vs. multiple bursts) and burst size may affect the magnitude of the LVC response. In 11 young men, arterial blood pressure, common femoral artery blood flow, and MSNA were continuously recorded during 20 min of supine rest. Signal averaging was used to characterize percent changes in LVC for 15 cardiac cycles following heartbeats associated with and without MSNA bursts. LVC significantly decreased following MSNA bursts, reaching a nadir during the 6th cardiac cycle (single bursts, -2.9 ± 1.1%; and multiple bursts, -11.0 ± 1.4%; both, P < 0.001). Individual MSNA burst amplitudes and the total amplitude of consecutive bursts were related to the magnitude of peak decreases in LVC. In contrast, cardiac cycles without MSNA bursts were associated with a significant increase in LVC (+3.1 ± 0.5%; P < 0.001). Total vascular conductance decreased in parallel with LVC also reaching a nadir around the peak rise in arterial blood pressure following an MSNA burst. Collectively, these data are the first to assess beat-by-beat sympathetic vascular transduction in resting humans, demonstrating robust and dynamic decreases in LVC following MSNA bursts, an effect that was absent for cardiac cycles without MSNA bursts.

Lower limb-localized vascular phenomena explain initial orthostatic hypotension upon standing from squat

The cause(s) of initial orthostatic hypotension (transient fall in blood pressure within 15 s upon active rising) have not been established. We tested the hypothesis that this hypotension is due to local vascular phenomena in contracting leg muscles from the brief effort of standing up. Seventeen young healthy subjects (2 male and 15 female, 22.5 ± 1.0 years) performed an active rise from resting squat after a 10-s squat, a 1-min squat, or a 5-min squat. Beat-by-beat arterial blood pressure, cardiac output, heart rate, and stroke volume (Finometer finger photoplethysmography) and right common femoral artery blood flow (Doppler and Echo ultrasound) were recorded. Data are means ± SE. Quiet standing before squat represented baseline. Peak increases in lower limb and total vascular conductance (ml·min(-1)·mmHg(-1)) upon standing were not different within squat conditions (10-s squat, 50.0 ± 12.4 vs. 44.3 ± 5.0; 1-min squat, 54.7 ± 9.2 vs. 50.5 ± 4.5; 5-min squat, 67.4 ± 13.7 vs. 58.8 ± 3.9; all P > 0.574). Mean arterial blood pressure (in mmHg) fell to a nadir well below standing baseline in all conditions despite increases in cardiac output. The hypotension predicted by the increase in leg vascular conductance accounted for this hypotension [observed vs. predicted (in mmHg): 10-s squat, -17.1 ± 2.1 vs. -18.3 ± 5.5; 1-min squat, -22.0 ± 3.8 vs. -25.3 ± 4.9; 5-min squat, -28.3 ± 4.0 vs. -29.2 ± 6.7]. We conclude that rapid contraction induced dilation in leg muscles with the effort of standing, along with a minor potential contribution of elevated lower limb arterio-venous pressure gradient, outstrips compensatory cardiac output responses and is the cause of initial orthostatic hypotension upon standing from squat.

The Effect Of Muscle Vibration Training on Femoral Artery Blood Velocity And Oxygen Uptake Kinetics

Acute and chronic whole body and targeted muscle vibration training has been shown to increase dynamic and isometric strength (Issurin et al, 1994), most likely as a result of altered neuromuscular activation (Bosco et al, 1999). In addition, whole body vibration has been shown to increase popliteal artery blood flow (Kerschan-Schindl et al, 2001) and common femoral artery blood flow (Lythgo et al 2008). PURPOSE: The effect of knee extension exercise with and without super-imposed targeted leg vibration on pulmonary oxygen uptake (VO2 ml-1kg-1min-1) and femoral artery blood velocity (cm/s) was investigated in the present study.: METHODS: Six healthy male subjects participated in this two trial study (age: 21.7 ± 2.3 y; weight: 78.8 ± 7.0 kg; height: 174.5 ± 0.09 cm). Trials were allocated by systematic rotation. Subjects completed 6 sets of 20 repetitions at 25% of their knee extension one repetition maximum (1RM), with 4 min rest between sets. In one of the trials 10 Hz vibration was delivered to the exercising legs via a custom designed device Vibrex (Exoscience Ltd).: RESULTS: Peak force was significantly higher in the vibrated than non-vibrated trials (8.4 ± 1.32% p=0.027), however total work done was not significantly different between trials (81.4 ± 3.2 kJ non-vibration vs 79.9 ± 4.1 kJ vibration trial). Pulmonary oxygen uptake was 12 ± 1% higher in vibration than the non-vibration trials, but this did not reach statistical significance. Heart rate (HR, bpm) was more elevated during exercise and recovery in the vibration vs the non-vibration conditions (5.3 ± 0.99 % and 9.6 ± 1.71 % respectively) but only the recovery HR achieved statistical significance (p=0.016). However, normalised mean peak femoral artery blood velocity tended to be lower in the vibration than the non-vibration trials (3.35 ± 2.73%, nsd).: CONCLUSIONS: The strong tendency for increased pulmonary oxygen uptake during the vibration trials in the absence of any increase in femoral artery mean peak blood velocity could be explained either by vibration-induced improvements in micro-circulation of the quadriceps muscle or altered motor unit recruitment and/or firing patterns. In order to discriminate between these two possible mechanisms, future studies should include muscle oxygenation and EMG data capture.:

The effect of AMPD1 genotype on blood flow response to sprint exercise

Inherited deficiency of skeletal muscle myoadenylate deaminase (mAMPD) is a genetic disorder characterized primarily by a 34C>T transition in exon 2 of the AMPD1 gene. mAMPD deficient individuals exhibit alterations in ATP catabolic flow, resulting in greater adenosine accumulation during high intensity exercise that may possibly enhance exercise-induced hyperaemia. This study tested the hypothesis that individuals with diminished mAMPD activity due to mutations in the AMPD1 gene develop a greater and faster blood flow response to high intensity exercise than individuals with two AMPD1 normal alleles (NN). Four 34C>T homozygotes, two compound heterozygotes (34C>T in one allele and a recently identified 404delT mutation in the other AMPD1 allele), collectively termed MM, one 34C>T heterozygote (NM) and eight NN males were studied. They performed a 30 s Wingate cycling test with monitoring of power output and other parameters of exercise performance. Common femoral artery blood flow was measured before and after (up to 25 min) exercise, using ultrasonography. Mean power during Wingate cycling was approximately 10% lower in MM/NM than in NN; p<0.01. Blood flow response to exercise also differed between MM/NM and NN individuals (ANOVA; p<0.001). There was also a difference in peak post-exercise blood flow (p<0.05), and the subsequent fall in blood flow during the recovery phase (T1/2) occurred more than twice as fast in MM/NM compared to NN subjects (7.8+/-1.1 min vs. 16.1+/-1.4 min, p<0.001). These results suggest a better circulatory adaptation to exercise in individuals with diminished mAMPD activity, probably due to an AMPD1 genotype-dependent increase in adenosine formation.

Measuring the rate of change of haemodynamic response at the onset of exercise in normal limbs and those with intermittent claudication

Patients with claudication have an inadequate haemodynamic response to exercise. Blood flow response will not only have a magnitude, but also a rate of change. There is scope for investigating these parameters, as manipulation of the factors which control them may benefit work to improve the treatment for claudication. This work compares the responses for patients with one normal limb and one with intermittent claudication. A custom-built ergometer allows unilateral, infragenicular plantar flexion exercise, whilst common femoral artery blood flow can be measured continuously by Duplex ultrasound. This apparatus was used to measure blood flow before, at the onset of and during a 5 W square-wave exercise stimulus in 15 patients. The claudicant group had a mean steady-state gain that was approximately half that of the normal group at around 170 ml min−1 (p < 0.001) and a response time that was much shorter (p = 0.006). A mean response time of 21.0 ± 1.4 s was achieved in claudicant limbs compared to 31.8 ± 2.9 s in normals. However, the average rate of change of blood flow during this response time was estimated to still be greater for the normal group, at 431.7 ± 47.1 ml min−2, than for the claudicant group. The differences in magnitude and rate of change of limb blood flow response to exercise in claudicants were significant and may have implications for the treatment of claudication.

Femoral Artery Blood Flow in Infants and Children

BackgroundWe measured Doppler parameter of common femoral artery (CFA) blood flow in infants and children and investigated how far these parameters change with age, height, weight, body mass index (BMI), and body surface area (BSA).Material and MethodsCFA was investigated in 97 infants and children (43 females, 54 males, ages ranged from 0.13 to 220 months) on both sides in a supine position after 5 min rest using a 7.5-MHz linear transducer (Type Elegra, Siemens, Germany) 1 cm proximal to the femoral bifurcation. Peak systolic velocity, end-diastolic velocity, blood flow volume, mean average velocity, resistance index, and pulsatility index were measured.ResultsTheoretically, Doppler parameters could change with age, height, weight, BMI, and BSA. Because age, weight, height, and BSA were highly correlated (Spearman correlation coefficient &gt; 0.90) only one of these variables could be included in a regression model. Only diameter and flow velocity (FV) correlated with age and height. Peak systolic velocity, mean average velocity, pulsatility index, and resistance index did not. Correlation between BMI and age and BMI and height was small. A regression model for the natural logarithm of FV was estimated: ln(FV) = −5.853 + 0.021 height + 0.049 BMI (R2= 0.73, p &lt; 0.0001 of height, p value of BMI: 0.028; p value of intercept: &lt; 0.0001). The 95% confidence intervals were: −6.470 to −5.237 for the intercept, 0.006 to 0.093 for BMI, and 0.017 to 0.025 for height. Predicted FV and their 95% confidence intervals were calculated. The upper confidence limits were 8–10 times that of the lower ones.ConclusionOnly FV showed height- and BMI-dependent changes in growing children. Prediction of FV in individual arteries was possible, but with a large range.

Determination of Femoral Artery Occlusion Using Principal Component Analysis of Doppler Signals

The aim of this study is to scrutinize the ability of principal component analysis (PCA) over power spectral densities (PSD) for common femoral artery blood flow study. Doppler femoral artery signals of patients with occluded arteries and of healthy subjects were recorded. Then, power spectral densities of these signals were obtained using the Welch method. To clearly determine the difference between the groups of occluded patients and healthy subjects, PCA was implemented with patients and healthy matrices derived from PSD. The basic differences between the healthy and occluded patients were acquired with 1st principal component. The use of PCA of physiological waveforms is presented as a powerful method likely to be incorporated into future medical signal processing.