Delaying Suspension Syndrome Onset in Aerially Suspended Victims Through Leg Raising

INTRODUCTION

Suspension syndrome (SS) develops when venous blood pools in extremities of passively suspended individuals, resulting in presyncopal symptoms and potential unconsciousness or death independent of additional injuries. We investigated use of leg raising to delay onset of SS, as it can decrease venous pooling and increase cardiac return and systemic perfusion.

METHODS

Participants were suspended in rock climbing harnesses at an indoor climbing wall in a legs-dangling control position or a legs-raised interventional position to compare physiological outcomes between groups. Participants were suspended for a maximum of 45 min. Onset of 2 or more symptoms of SS, such as vertigo, lightheadedness, or nausea, halted suspension immediately. We recorded each participant's heart rate, blood pressure, oxygen saturation, lower leg oxygen saturation, pain rating, and presyncope scores presuspension, midsuspension, and postsuspension, as well as total time suspended.

RESULTS

There were 24 participants. There was a significant difference in total time suspended between groups (43.05±6.7 min vs 33.35±9.02 min, p=0.007). There was a significant difference in heart rate between groups overall (p=0.012), and between groups, specifically at the midsuspension time interval (80±11 bpm vs 100±17 bpm, p=0.003). Pain rating was significantly different between groups (p=0.05). Differences in blood pressure, oxygen saturation, lower leg oxygen saturation, and presyncope scores were not significant.

CONCLUSION

Leg raising lengthened the time individuals tolerated passive suspension and delayed symptom onset.

Effect of passive leg raising on the cross-sectional area of the right internal jugular vein in patients with obesity: a randomised controlled trial protocol

BACKGROUND

Venous access in patients with obesity presents significant challenges. The success of central venous catheterisation largely depends on the cross-sectional area (CSA) of the internal jugular vein (IJV). While techniques like the Trendelenburg position have been traditionally used to increase IJV CSA, recent studies suggest its ineffectiveness in patients with obesity. Conversely, the potential of the effect of passive leg raising (PLR) has not been thoroughly investigated in this group of patients.

METHODS

This protocol outlines a planned randomised controlled trial to evaluate the effect of PLR on the CSA of the IJV in patients with obesity slated for central venous catheterisation. The protocol involves dividing 40 participants into two groups: one undergoing PLR and another serving as a control group without positional change. The protocol specifies measuring the CSA of the IJV via ultrasound as the primary outcome. Secondary outcomes will include the success rates of right IJV cannulation. The proposed statistical approach includes the use of t-tests to compare the changes in CSA between the two groups, with a significance threshold set at p<0.05.

ETHICS APPROVAL

This study has been approved by the Institutional Review Board of Shanghai Tongren Hospital. All the participants will provide informed consent prior to enrolment in the study. Regarding the dissemination of research findings, we plan to share the results through academic conferences and peer-reviewed publications. Additionally, we will communicate our findings to the public and professional communities, including patient advocacy groups.

TRIAL REGISTRATION NUMBER

ChiCTR: ChiCTR2400080513.

The role of T-type calcium channels in elderly human vascular function: A pilot randomized controlled trial

Endothelial dysfunction develops with age and may precede cardiovascular disease. Animal data suggest that T-type calcium channels play an important role in endothelial function, but data from humans are lacking. This study included 15 healthy, sedentary, elderly males for a double blinded, randomized controlled trial. For 8 weeks, they were given 40 mg/day of either efonidipine (L- and T-type calcium channel blocker (CCB)) or nifedipine (L-type CCB). Vascular function was evaluated by graded femoral arterial infusions of acetylcholine (ACh; endothelium-dependent vasodilator) and sodium nitroprusside (endothelium-independent vasodilator) both with and without co-infusion of N-acetylcysteine (NAC; antioxidant). We measured leg blood flow and mean arterial pressure and calculated leg vascular conductance to evaluate the leg vascular responses. Despite no significant change in blood pressure in either group, we observed higher leg blood flow responses (Δ 0.43 ± 0.45 l/min, P = 0.006) and leg vascular conductance (Δ 5.38 ± 5.67 ml/min/mmHg, P = 0.005) to intra-arterial ACh after efonidipine, whereas there was no change in the nifedipine group, and no differences between groups. We found no upregulation of endothelial nitric oxide synthase in vastus lateralis muscle biopsies within or between groups. Smooth muscle cell responsiveness was unaltered by efonidipine or nifedipine. Intravenous co-infusion of NAC did not affect endothelium-dependent vasodilatation in either of the CCB groups. These results suggest that 8 weeks' inhibition of T- and L-type calcium channels augments endothelium-dependent vasodilatory function in healthy elderly males. Further studies are required to elucidate if T-type calcium channel inhibition can counteract endothelial dysfunction.

Acute effects of low-intensity one-legged electrical muscle stimulation on arterial stiffness in experimental and control limbs

The aim of this study was to examine the acute effects of low-intensity one-legged electrical muscle stimulation (EMS) for skeletal muscle on arterial stiffness in EMS and non-EMS legs. Eighteen healthy subjects received two different protocols (Control (CT) and Experimental (ET) trials) in random order on separate days. EMS was applied to the left lower limb at 4 Hz for 20 min at an intensity corresponding to an elevation in pulse rate of approximately 15 beats/min (10.9 ± 5.1% of heart rate reserve). Before and after the experiment, arterial stiffness parameters in the control right leg (CRL) and control left leg (CLL) in CT and non-EMS leg (NEL) and EMS leg (EL) in ET were assessed by pulse wave velocity (baPWV, faPWV) and cardio-ankle vascular index (CAVI). No significant changes in all parameters were observed in either leg in CT. Conversely, in ET, low-intensity, single-leg EMS significantly reduced CAVI, baPWV, and faPWV in the EL, but not in the NEL. Acute, low-intensity single-leg EMS reduces arterial stiffness only in the EL. These data support our idea that physical movement-related regional factors rather than systematic factors are important for inducing acute reductions in arterial stiffness.

Reducing thrombotic risks in video gamers: investigating the benefits of walking and compression sleeves on blood hemodynamics

With the growing popularity of video gaming, deep vein thromboses are increasingly being reported in gamers. This study aimed to compare the effects of lower leg graduated compression sleeves and a 6-min walking break during prolonged gaming on blood flow and hemodynamics in competitive sport players to help mitigate this risk. Ten healthy gamers (19.6 ± 1.2 yr old; 9 men) consented to participate in this mixed-model crossover design study that consisted of three visits. In visit 1, participants engaged in continuous 2-h video game play wearing no compression (continuous). Visits 2 and 3 involved 2-h play wearing compression sleeves (compression) and 2-h game play interrupted at 1 h by a 6-min walk (walk). Doppler ultrasound measurements of the left popliteal artery were taken at 30, 60, 90, and 120 min, to record vessel diameter, blood flow velocity, and blood flow volume. Participants completed a survey to assess their perception of each approach. There was a significant interaction between conditions for blood flow and blood velocity (P = 0.01, P < 0.001). Post hoc analysis demonstrated a greater decrease in blood flow and blood velocity in the continuous group compared with the walk group at the 90-min mark (P = 0.04, P = 0.01). No differences were found between the compression and walk groups or between the continuous and compression groups (P = 0.42, P = 0.69). No interactions were observed in diameter, mean arterial pressure, or heart rate. This study suggests that incorporating a 6-min walk every 60 min during prolonged gaming is advisable to counteract the negative effects on blood flow hemodynamics.NEW & NOTEWORTHY A 6-min light-intensity walking break during gaming can effectively combat the adverse effects of prolonged sitting, surpassing compression garments. Prolonged sitting reduces blood flow velocity, potentially leading to deep vein thrombosis (DVT). Compression sleeves help, with superior results after a 6-min walk at 60 min. Although compression stockings offer moderate improvements, a 6-min active break proves more effective. These findings offer promising interventions for gamers' health, initiating guidelines to mitigate DVT risk during gaming.

Sitting leg vasculopathy: potential adaptations beyond the endothelium

Increased sitting time, the most common form of sedentary behavior, is an independent risk factor for all-cause and cardiovascular disease mortality; however, the mechanisms linking sitting to cardiovascular risk remain largely elusive. Studies over the last decade have led to the concept that excessive time spent in the sitting position and the ensuing reduction in leg blood flow-induced shear stress cause endothelial dysfunction. This conclusion has been mainly supported by studies using flow-mediated dilation in the lower extremities as the measured outcome. In this review, we summarize evidence from classic studies and more recent ones that collectively support the notion that prolonged sitting-induced leg vascular dysfunction is likely also attributable to changes occurring in vascular smooth muscle cells (VSMCs). Indeed, we provide evidence that prolonged constriction of resistance arteries can lead to modifications in the structural characteristics of the vascular wall, including polymerization of actin filaments in VSMCs and inward remodeling, and that these changes manifest in a time frame that is consistent with the vascular changes observed with prolonged sitting. We expect this review will stimulate future studies with a focus on VSMC cytoskeletal remodeling as a potential target to prevent the detrimental vascular ramifications of too much sitting.

Vascular dysfunction and the age-related decline in critical power

Ageing results in lower exercise tolerance, manifested as decreased critical power (CP). We examined whether the age-related decrease in CP occurs independently of changes in muscle mass and whether it is related to impaired vascular function. Ten older (63.1 ± 2.5 years) and 10 younger (24.4 ± 4.0 years) physically active volunteers participated. Physical activity was measured with accelerometry. Leg muscle mass was quantified with dual X-ray absorptiometry. The CP and maximum power during a graded exercise test (PGXT ) of single-leg knee-extension exercise were determined over the course of four visits. During a fifth visit, vascular function of the leg was assessed with passive leg movement (PLM) hyperaemia and leg blood flow and vascular conductance during knee-extension exercise at 10 W, 20 W, slightly below CP (90% CP) and PGXT . Despite not differing in leg lean mass (P = 0.901) and physical activity (e.g., steps per day, P = 0.735), older subjects had ∼30% lower mass-specific CP (old = 3.20 ± 0.94 W kg-1 vs. young = 4.60 ± 0.87 W kg-1 ; P < 0.001). The PLM-induced hyperaemia and leg blood flow and/or conductance were blunted in the old at 20 W, 90% CP and PGXT (P < 0.05). When normalized for leg muscle mass, CP was strongly correlated with PLM-induced hyperaemia (R2  = 0.52; P < 0.001) and vascular conductance during knee-extension exercise at 20 W (R2  = 0.34; P = 0.014) and 90% CP (R2  = 0.39; P = 0.004). In conclusion, the age-related decline in CP is not only an issue of muscle quantity, but also of impaired muscle quality that corresponds to impaired vascular function.

A case of vitiligo that followed the path of a varicose vein in the lower leg

Vitiligo is an acquired chronic depigmenting disorder of the skin and is characterized by the destruction of melanocytes. One of the clinical features of vitiligo is that damage to normal skin frequently results in the formation of depigmented macules, which is known as Köebner's phenomenon (KP). Here, we presented a case of vitiligo, in which depigmented macules followed the course of a dilated varicose vein. Dilatation of blood vessels was considered to contribute to the development of the vitiliginous lesions as a trigger for KP. Any kind of skin injury can trigger KP, but this is only the second case in which a dilated blood vessel caused KP in vitiligo. J. Med. Invest. 71 : 177-178, February, 2024.

Generation of a Predictive Clinical Model for Isolated Distal Deep Vein Thrombosis (ICMVT) Detection

BACKGROUND Isolated distal deep vein thrombosis (ICMVT) increases the risk of pulmonary embolism. Although predictive models are available, their utility in predicting the risk is unknown. To develop a clinical prediction model for isolated distal calf muscle venous thrombosis, data from 462 patients were used to assess the independent risk variables for ICMVT. MATERIAL AND METHODS The area under curve (AUC) for Model A and Model B were calculated and other risk factors were based on age, pitting edema in the symptomatic leg, calf swelling with least 3 cm larger than the asymptomatic leg, recent bed rest for 3 days or more in the past 4 weeks, requiring general or major surgery with regional anesthesia, sex, and local tenderness distributed along the deep venous system as independent predictors of calf muscle venous thrombosis. Model A includes the risk variables for C-reactive protein and D-dimer. RESULTS The area under ROC curve for Model A training set was 0.924 (95% CI: 0.895-0.952), the area under ROC curve for Model B training set was 0.887 (95% CI: 0.852-0.922), and the AUC difference between the 2 models was statistically significant (P<0.001); the area under ROC curve for Model A obtained in the validation set was 0.902 (95% CI: 0.844-0.961), the area under ROC curve for Model B was 0.842 (95% CI: 0. 0.773-0.910), and the difference between the 2 models was statistically significant (P=0.012). CONCLUSIONS Predictive Model A better predicts isolated calf muscle venous thrombosis and is able to help clinicians rapidly and early diagnose ICMVT, displaying higher utility for missed diagnosis prevention and disease therapy.

[Anatomical study of the architecture of the cutaneous branch-chained blood vessels in the medial lower leg in adult]

Objective: To investigate the architecture of the cutaneous branch-chained blood vessels in the medial lower leg and provide the anatomical basis for design and clinical application of the cutaneous branch-chained flap from this region. Methods: The experimental research method was used. From March to May 2023, the anatomical study was conducted on the 5 voluntarily donated fresh adult (aged 50 to 70 years, all male) cadaveric specimens from Hangzhou Normal University School of Basic Medical Sciences. The fine anatomy under microscope was performed on each lower leg specimens of 5 corpses (1 lower leg specimen was conducted with digital radiography (DR) scan before fine anatomy), to observe, measure, and record the course of posterior tibial artery, quantity of perforator, the distance between the perforating point of each perforator and the medial condyle of tibia, the external diameter of posterior tibial artery perforator, the length of perforator pedicle, the horizontal distance between the posterior tibial artery perforator and the saphenous nerve, and the course of each perforator within superficial fascia after crossing the deep fascia and the distribution of the cutaneous branch-chains. The DR scan under the perfusion of barium sulfate was conducted in one lower leg specimen to observe the distribution of cutaneous branch-chained vascular network (hereinafter referred to as vascular chain) between perforators. Transparent skin specimen was made from one leg specimen after anatomy to observe the distribution of perforators and vascular chains between perforators. Results: In 5 lower leg specimens, the upper part of posterior tibial artery was located deep in soleus muscle, and the lower part was located between the medial edge of gastrocnemius muscle and flexor digitorum longus muscle. A total of 28 posterior tibial artery perforators were identified, with an average of 5.6 branches in each lower leg. The distance between the perforating point of perforator and the medial condyle of tibia ranged from 6.5 to 36.0 cm, mainly distributed at 22.0 (15.1, 28.1) cm from the medial condyle of tibia, in zones 3 to 6. The external diameters of perforators of posterior tibial arteries were 0.7-1.1 mm. The length of perforator pedicle was 1.0-4.5 cm, and the horizontal distance between the posterior tibial artery perforator and the saphenous nerve was 0.5-3.0 cm. The fine anatomy under microscope showed that the posterior tibial artery perforators had long upward and downward branches after crossing the deep fascia, and the ascending branches and descending branches were anastomosed longitudinally to form the nutrient cutaneous branch-chain in the medial lower leg. DR scan and transparent skin specimen both showed that longitudinal vascular chain was formed between the posterior tibial artery perforators, the transparent skin specimen also showed that longitudinal blood vessel chains included the direct connecting vessels in the adipose layer and the indirect connecting vessels in the subdermal layer. Conclusions: The cutaneous branch-chained vessels in the medial lower leg are constructed by posterior tibial artery perforators, direct connecting vessels, indirect connecting vessels, and traffic branches. The cutaneous branch-chained flap is reliable in terms of vascular anatomy, and can carry the saphenous nerve for partial restoration of its sensation, thus it is an ideal flap.

Doppler Ultrasound-Based Leg Blood Flow Assessment During Single-Leg Knee-Extensor Exercise in an Uncontrolled Setting

Doppler ultrasound has revolutionized the assessment of organ blood flow and is widely used in research and clinical settings. While Doppler ultrasound-based assessment of contracting leg muscle blood flow is common in human studies, the reliability of this method requires further investigation. Therefore, this study aimed to investigate the within-day test-retest, between-day test-retest, and inter-rater reliability of Doppler ultrasound for assessing leg blood flow during rest and graded single-leg knee-extensions (0 W, 6 W, 12 W, and 18 W), with the ultrasound probe being removed between measurements. The study included thirty healthy subjects (age: 33 ± 9.3, male/female: 14/16) who visited the laboratory on two different experimental days separated by 10 days. The study did not control for major confounders such as nutritional state, time of day, or hormonal status. Across different exercise intensities, the results demonstrated high within-day reliability with a coefficient of variation (CV) ranging from 4.0% to 4.3%, acceptable between-day reliability with a CV ranging from 10.1% to 20.2%, and inter-rater reliability with a CV ranging from 17.9% to 26.8%. Therefore, in a real-life clinical scenario where controlling various environmental factors is challenging, Doppler ultrasound can be used to determine leg blood flow during submaximal single-leg knee-extensor exercise with high within-day reliability and acceptable between-day reliability when performed by the same sonographer.

Utility of preoperative colour flow Doppler assessment of perforator anatomy in medial sural artery perforator (MSAP) free flaps

PURPOSE

It is known that the vascular perforators upon which the medial sural artery perforator (MSAP) flap is based are subject to considerable variation. This study seeks to evaluate the use of colour flow Doppler (CFD) as an imaging technique to establish the presence of suitable vessels, the discriminatory findings from that imaging, the rate of flap abandonment and flap complications.

METHODS

All patients undergoing MSAP in our institution since 2015 had a pre-operative CFD using a standardised technique. A prior group of 22 patients not having CFD acted as a control group. Data were  collected prospectively.

RESULTS

Fourteen patients had CFD. In one patient, no suitable vessels were found. In 13 patients, vessels of suitable size and position were identified, which then correlated precisely with operative findings. Three had suitable vessels in one leg only. No flaps in the CFD group were abandoned. One flap in the CFD group was partially lost. One flap in the prior control group was abandoned.

CONCLUSIONS

CFD provided reliable discriminatory information to decide on flap suitability/which leg and correlated precisely with operative findings, with no flap abandonment. Flap survival rate was very high.

Delayed rupture of peroneal artery pseudoaneurysm following endovascular treatment in a patient with chronic limb-threatening ischemia: A case report

Below-the-knee (BTK) pseudoaneurysms that occur after endovascular therapy (EVT) and result in delayed rupture have rarely been reported. In this report, we present a rare case of an 86-year-old man with chronic limb-threatening ischemia who developed delayed rupture of an idiopathic pseudoaneurysm of the peroneal artery (PA) following EVT. The PA chronic total occlusion (CTO) was successfully crossed using a guidewire via an antegrade approach, however, subintimal crossing was confirmed by intravascular ultrasound. Balloon angioplasty was then performed using an appropriately sized balloon, resulting in successful recanalization of the PA CTO with minor dissection and no complications. Postoperatively, the patient's condition was stable until he suddenly complained of right calf pain 10 days after EVT. Computed tomography revealed a rupture of the PA pseudoaneurysm. Urgent angiography revealed two pseudoaneurysms, one saccular and the other spindle-shaped. The ruptured saccular aneurysm was successfully excluded through coil embolization and stent graft placement. To the best of our knowledge, this is the first reported case of delayed rupture of a BTK pseudoaneurysm following EVT. Balloon angioplasty in the subintimal space can lead to the formation of a pseudoaneurysm and its delayed rupture.

Early-stage chronic venous disorder as a cause of leg pain overlooked for lumbar spinal disease

Leg pain can be caused by both lumbar spinal disease and chronic venous disorder (CVD) of leg veins, but their clinical differences have not been thoroughly investigated. This study aimed to determine the incidence of CVD among patients visiting a spine center for leg pain. A total of 196 cases underwent ultrasound examination with a diagnosis rate were 85.7% (168 cases). CVD-diagnosed cases were divided into two groups based on the severity of lumbar spinal disease. The Clinical grades, symptom areas, and symptom types were compared. The differences in symptom improvements with vasoactive medication were also assessed. The most common symptom area was calf then the foot in CVD, while calf then thigh in lumbar spinal disease. Tingling-paresthesia was the most common symptom type for both, with pain and cramping similarly common in CVD and pain more common than cramping in lumbar spinal disease. Considering that the majority of CVD cases (78.6%) had minor cutaneous changes and almost half of cases (41.7%) had refluxes only in tributaries, significant differences in symptom improvement in CVD-dominant group suggested that early-stage venous reflux is a symptomatic disease and a possible cause of leg pain and other symptoms.

Bilateral persistent sciatic arteries presenting with lower extremity claudication

This is a case report of a woman in her 60s with Rutherford class 3 bilateral calf claudication and a resting right Ankle Brachial Index (ABI) 0.49 and left ABI 0.57. The arteriogram of lower extremities demonstrates bilateral persistent sciatic arteries (PSAs). The patient had severe stenosis of left common iliac artery, and thus underwent successful stenting resulting in normalisation of flow and filling of PSA with symptom resolution.

The exercise pressor reflex - a pressure-raising mechanism with a limited role in regulating leg perfusion during locomotion in young healthy men

We investigated the role of the exercise pressor reflex (EPR) in regulating the haemodynamic response to locomotor exercise. Eight healthy participants (23 ± 3 years,V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ : 49 ± 6 ml/kg/min) performed constant-load cycling exercise (∼36/43/52/98%V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ ; 4 min each) without (CTRL) and with (FENT) lumbar intrathecal fentanyl attenuating group III/IV locomotor muscle afferent feedback and, thus, the EPR. To avoid different respiratory muscle metaboreflex and arterial chemoreflex activation during FENT, subjects mimicked the ventilatory response recorded during CTRL. Arterial and leg perfusion pressure (femoral arterial and venous catheters), femoral blood flow (Doppler-ultrasound), microvascular quadriceps blood flow index (indocyanine green), cardiac output (inert gas breathing), and systemic and leg vascular conductance were quantified during exercise. There were no cardiovascular and ventilatory differences between conditions at rest. Pulmonary ventilation, arterial blood gases and oxyhaemoglobin saturation were not different during exercise. Furthermore, cardiac output (-2% to -12%), arterial pressure (-7% to -15%) and leg perfusion pressure (-8% to -22%) were lower, and systemic (up to 16%) and leg (up to 27%) vascular conductance were higher during FENT compared to CTRL. Leg blood flow, microvascular quadriceps blood flow index, and leg O2 -transport and utilization were not different between conditions (P > 0.5). These findings reflect a critical role of the EPR in the autonomic control of the heart, vasculature and, ultimately, arterial pressure during locomotor exercise. However, the lack of a net effect of the EPR on leg blood flow challenges the idea of this cardiovascular reflex as a key determinant of leg O2 -transport during locomotor exercise in healthy, young individuals. KEY POINTS: The role of the exercise pressor reflex (EPR) in regulating leg O2 -transport during human locomotion remains uncertain. We investigated the influence of the EPR on the cardiovascular response to cycling exercise. Lumbar intrathecal fentanyl was used to block group III/IV leg muscle afferents and debilitate the EPR at intensities ranging from 30% to 100%V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ . To avoid different respiratory muscle metaboreflex and arterial chemoreflex activation during exercise with blocked leg muscle afferents, subjects mimicked the ventilatory response recorded during control exercise. Afferent blockade increased leg and systemic vascular conductance, but reduced cardiac output and arterial-pressure, with no net effect on leg blood flow. The EPR influenced the cardiovascular response to cycling exercise by contributing to the autonomic control of the heart and vasculature, but did not affect leg blood flow. These findings challenge the idea of the EPR as a key determinant of leg O2 -transport during locomotor exercise in healthy, young individuals.

Effects on hemodynamic enhancement and discomfort of a new textile electrode integrated in a sock during calf neuromuscular electrical stimulation

PURPOSE

To compare fixed transverse textile electrodes (TTE) knitted into a sock versus motor point placed standard gel electrodes (MPE) on peak venous velocity (PVV) and discomfort, during calf neuromuscular electrical stimulation (calf-NMES).

METHODS

Ten healthy participants received calf-NMES with increasing intensity until plantar flexion (measurement level I = ML I), and an additional mean 4 mA intensity (ML II), utilizing TTE and MPE. PVV was measured with Doppler ultrasound in the popliteal and femoral veins at baseline, ML I and II. Discomfort was assessed with a numerical rating scale (NRS, 0-10). Significance was set to p < 0.05.

RESULTS

TTE and MPE both induced significant increases in PVV from baseline to ML I and significantly higher increases to ML II, in both the popliteal and femoral veins (all p < 0.001). The popliteal increases of PVV from baseline to both ML I and II were significantly higher with TTE versus MPE (p < 0.05). The femoral increases of PVV from baseline to both ML I and II were not significantly different between TTE and MPE. TTE versus MPE resulted at ML I in higher mA and NRS (p < 0.001), and at ML II in higher mA (p = 0.005) while NRS was not significantly different.

CONCLUSION

TTE integrated in a sock produces intensity-dependent increases of popliteal and femoral hemodynamics comparable to MPE, but results in more discomfort at plantar flexion due to higher current required. TTE exhibits in the popliteal vein higher increases of PVV compared to MPE.

TRIAL REGISTRATION

Trial_ID: ISRCTN49260430. Date: 11/01/2022. Retrospectively registered.

An anatomical study of the tibial nerve branches innervating the posterior tibial artery

The arteries of the lower limbs are innervated by vascular branches (VBs) originating from the lumbar sympathetic trunk and branches of the spinal nerve. Although lumbar sympathectomy is used to treat nonreconstructive critical lower limb ischemia (CLLI), it has limited long-term effects. In addition, the anatomical structure of tibial nerve (TN) VBs remain incompletely understood. This study aimed to clarify their anatomy and better inform the surgical approach for nonreconstructive CLLI. Thirty-six adult cadavers were dissected under surgical microscopy to observe the patterns and origin points of VBs under direct vision. The calves were anatomically divided into five equal segments, and the number of VB origin points found in each was expressed as a proportion of the total found in the whole calf. Immunofluorescence staining was used to identify the sympathetic nerve fibers of the VBs. Our results showed that the TN gave off 3-4 VBs to innervate the posterior tibial artery (PTA), and the distances between VBs origin points and the medial tibial condyle were: 24.7 ± 16.3 mm, 91.7 ± 66.1 mm, 199.6 ± 52.0 mm, 231.7 ± 38.5 mm, respectively. They were mainly located in the first (40.46%) and fourth (31.68%) calf segments, and immunofluorescence staining showed that they contained tyrosine hydroxylase-positive sympathetic nerve fibers. These findings indicate that the TN gives off VBs to innervate the PTA and that these contain sympathetic nerve fibers. Therefore, these VBs may need to be cut to surgically treat nonreconstructable CLLI.

Lower limb hyperthermia augments functional hyperaemia during small muscle mass exercise similarly in trained elderly and young humans

NEW FINDINGS

What is the central question of the study? Ageing is postulated to lead to underperfusion of human limb tissues during passive and exertional hyperthermia, but findings to date have been equivocal. Thus, does age have an independent adverse effect on local haemodynamics during passive single-leg hyperthermia, single-leg knee-extensor exercise and their combination? What is the main finding and its importance? Local hyperthermia increased leg blood flow over three-fold and had an additive effect during knee-extensor exercise with no absolute differences in leg perfusion between the healthy, exercise-trained elderly and the young groups. Our findings indicate that age per se does not compromise lower limb hyperaemia during local hyperthermia and/or small muscle mass exercise.

ABSTRACT

Heat and exercise therapies are recommended to improve vascular health across the lifespan. However, the haemodynamic effects of hyperthermia, exercise and their combination are inconsistent in young and elderly people. Here we investigated the acute effects of local-limb hyperthermia and exercise on limb haemodynamics in nine healthy, trained elderly (69 ± 5 years) and 10 young (26 ± 7 years) adults, hypothesising that the combination of local hyperthermia and exercise interact to increase leg perfusion, albeit to a lesser extent in the elderly. Participants underwent 90 min of single whole-leg heating, with the contralateral leg remaining as control, followed by 10 min of low-intensity incremental single-leg knee-extensor exercise with both the heated and control legs. Temperature profiles and leg haemodynamics at the femoral and popliteal arteries were measured. In both groups, heating increased whole-leg skin temperature and blood flow by 9.5 ± 1.2°C and 0.7 ± 0.2 L min-1 (>3-fold), respectively (P < 0.0001). Blood flow in the heated leg remained 0.7 ± 0.6 and 1.0 ± 0.8 L min-1 higher during exercise at 6 and 12 W, respectively (P < 0.0001). However, there were no differences in limb haemodynamics between cohorts, other than the elderly group exhibiting a 16 ± 6% larger arterial diameter and a 51 ± 6% lower blood velocity following heating (P < 0.0001). In conclusion, local hyperthermia-induced limb hyperperfusion and/or small muscle mass exercise hyperaemia are preserved in trained older people despite evident age-related structural and functional alterations in their leg conduit arteries.

Venous congestion affects neuromuscular changes in pigs in terms of muscle electrical activity and muscle stiffness

Early detection of venous congestion (VC)-related diseases such as deep vein thrombosis (DVT) is important to prevent irreversible or serious pathological conditions. However, the current way of diagnosing DVT is only possible after recognizing advanced DVT symptoms such as swelling, pain, and tightness in affected extremities, which may be due to the lack of information on neuromechanical changes following VC. Thus, the goal of this study was to investigate acute neuromechanical changes in muscle electrical activity and muscle stiffness when VC was induced. The eight pigs were selected and the change of muscle stiffness from the acceleration and muscle activity in terms of integral electromyography (IEMG) was investigated in three VC stages. Consequently, we discovered a significant increase in the change in muscle stiffness and IEMG from the baseline to the VC stages (p < 0.05). Our results and approach can enable early detection of pathological conditions associated with VC, which can be a basis for further developing early diagnostic tools for detecting VC-related diseases.

The Outcome Of Pedicled Medial Sural Artery Perforating Flap For Proximal Leg Reconstruction

BACKGROUND

Reconstruction of defects around the knee and proximal leg are difficult to reconstruct. Out of the multiple flaps described for reconstruction, the pedicled Medial Sural Artery Perforating Flap (MSAP) has recently gained popularity. We conducted this study to assess the clinical outcomes of pedicled MSAP for this purpose at our hospital.

METHODS

A descriptive case series was conducted from April 2022 to March 2023. All patients above 18 years with defects around the knee and proximal leg were included. Patients with tissue loss in the calf area were excluded.

RESULTS

A total of 14 patients were included. Twelve (86%) were males, while only 2 were females (14%). The mean age was 33.5 years (±8.76). The most common cause of the defect was trauma (n=11, 85%). The Mean distance of the distal-most perforator from the popliteal crease was 12.714 (±1.990) cm (range 9-16 cm). It was observed that the most distal perforator is usually present in a 2 cm radius of the medial musculo-tendinous junction of the gastrocnemius. Complications were seen in 2 (14%) patients. The mean duration of hospital stay was 4.2 (±0.96) days. Patients were followed up weekly for the first two weeks and then at 1, 3 and 6 months.

CONCLUSIONS

MSAP Flap is a reliable thin, long pedicled fasciocutaneous flap with low donor site morbidity and aesthetically good results for reconstruction around the knee and proximal leg.

An Unreported Variation of Origin of Posterior Tibial Artery Encountered During Free Fibula Flap Harvest

ABSTRACT

Variations in the division of popliteal artery and origin of the 3 vascular systems are well documented. Here, we report a case in which the posterior tibial artery originated from the peroneal artery, in lower leg and then followed the normal course. The anomaly was detected intraoperatively precluding the harvest of free fibula flap. The procedure was abandoned and fibula was fixed using plates and screws and a free radial forearm flap was done over 2 mini-plates, which spanned the bone gap. A second bone flap procedure was to be planned in another sitting.The anomalous origin of posterior tibial artery from the peroneal artery in lower leg did not fall into any of the categories described previously by Kim et al (Ann Surg 1989;210:776-81.). In the event such atypical anatomy is encountered, it must be delineated, and the surgical plan adjusted accordingly. Flexibility in surgical approach can prevent vascular catastrophe.

Calf muscle pump pressure-flow cycle during ambulation

OBJECTIVE

Calf muscle pump (CMP) failure contributes to the severity and progression of chronic venous disease. Attempts to improve CMP function through resistance exercise have failed to improve chronic venous disease severity or quality of life, partially because the selection of the type of exercise was based on the assumption that the CMP ejects blood from the intramuscular venous sinuses (VSs), which has never been tested in humans. In the present study, we investigated the real-time changes in the pressure and size of the VS during the entire gait cycle of ambulation.

METHODS

We studied 12 lower extremities of nine healthy volunteers at rest and while walking on a treadmill at three different speeds (60, 90, and 120 steps/min). The changes in the VS cross-sectional area (CSA) and pressure were measured. Myography of the gastrocnemius muscle (GCM) and anterior tibial muscle (ATM) was used to register muscle activity. The relationship between the phases of the gait cycle and the measured parameters was analyzed using video records of all experiments.

RESULTS

The observed timing of events was consistent among all limbs studied. At rest, with the participants standing still, the VS pressure and CSA was 70.3 ± 4.2 mm Hg and 23.3 ± 14.6 mm2, respectively. During ambulation, at the first half of the stance, the GCM and ATM eccentrically contract, and the pressure is low (17 ± 8 mm Hg, 20 ± 12 mm Hg, and 29 ± 13 mm Hg at 1, 1.5, and 2 Hz, respectively), and the VS is collapsed. When the heel starts rising (the second half of the stance), the GCM concentrically contracts, the pressure increases, reaching its maximum value (143 ± 37, 134 ± 46, and 128 ± 41 mm Hg), and the VS opens, reaching its maximal size (1.8 ± 1.4 and 2.3 ± 2.2 mm2 at 1 and 1.5 Hz, respectively), followed by collapse of the VS. During the swing phase, the GCM relaxes, and the ATM concentrically contracts, resulting in a rapid decrease in pressure (2.6 ± 4.7, 1.1 ± 6.2, and -4.7 ± 3.2 mm Hg). The VS CSA remained negligible.

CONCLUSIONS

The GCM concentric contraction was associated with a simultaneous increase in VS pressure and CSA. GCM relaxation with ATM concentric contraction coincided with a decrease in VS pressure to negative values. The VSs do not fill but remain empty during the swing phase of ambulation, acting, not as a reservoir, but as a conduit, transferring blood from the network of intramuscular veins to the axial deep veins.

Unraveling the pathophysiology of lower-limb postthrombotic syndrome in adolescents: a proof-of-concept study

A better understanding of the pathophysiology of pediatric postthrombotic syndrome (PTS) is needed to develop strategies to treat this condition. We investigated calf pump function, exercise capacity, balance in power output, and changes in limb muscle oxygen saturation (SmO2) and fluid content during exercise in 10 pediatric patients with unilateral lower-limb PTS, and in age- and sex-matched controls (1:1-1:2 ratio). Outcomes were investigated using bioimpedance spectroscopy, torque-sensing pedals, and near-infrared spectroscopy during incremental- and constant-load cycling tests. The median age at participation was 17 years (25th-75th percentile, 15-18 years); 68% of participants were females. The median CAPTSure score in the affected leg of affected participants was 35 points (25th-75th percentile, 24-46 points), indicating moderate/severe PTS; 20% of patients had a history of central venous catheter-related thrombosis. Increasing PTS severity was associated with higher calf pump venous volume and higher ejection volume, leading to compensated calf pump performance. We found no evidence of PTS impact on exercise capacity. Leg contribution to power output was similar in affected and unaffected legs. However, the PTS-affected legs showed lower SmO2 during active cycling and recovery with increasing PTS severity, indicating impaired microvascular function in the muscle. These findings suggest that PTS severity is associated with impaired blood flow, presumably from elevated venous pressure during and after exercise. The fact that microvascular function is impaired in young patients with PTS underscores the relevance of developing strategies to mitigate the effects of this chronic vascular disease to minimize its deleterious effects as children grow older.

Pharmacological modulation of adrenergic tone alters the vasodilatory response to passive leg movement in young but not in old adults

The age-related increase in α-adrenergic tone may contribute to decreased leg vascular conductance (LVC) both at rest and during exercise in the old. However, the effect on passive leg movement (PLM)-induced LVC, a measure of vascular function, which is markedly attenuated in this population, is unknown. Thus, in eight young (25 ± 5 yr) and seven old (65 ± 7 yr) subjects, this investigation examined the impact of systemic β-adrenergic blockade (propanalol, PROP) alone, and PROP combined with either α1-adrenergic stimulation (phenylephrine, PE) or α-adrenergic inhibition (phentolamine, PHEN), on PLM-induced vasodilation. LVC, calculated from femoral artery blood flow and pressure, was determined and PLM-induced Δ peak (LVCΔpeak) and total vasodilation (LVCAUC, area under curve) were documented. PROP decreased LVCΔpeak (PROP: 4.8 ± 1.8, Saline: 7.7 ± 2.7 mL·mmHg-1, P < 0.001) and LVCAUC (PROP: 1.1 ± 0.7, Saline: 2.4 ± 1.6 mL·mmHg-1, P = 0.002) in the young, but not in the old (LVCΔpeak, P = 0.931; LVCAUC, P = 0.999). PE reduced baseline LVC (PE: 1.6 ± 0.4, PROP: 2.3 ± 0.4 mL·min-1·mmHg-1, P < 0.01), LVCΔpeak (PE: 3.2 ± 1.3, PROP: 4.8 ± 1.8 mL·min-1·mmHg-1, P = 0.004), and LVCAUC (PE: 0.5 ± 0.4, PROP: 1.1 ± 0.7 mL·mmHg-1, P = 0.011) in the young, but not in the old (baseline LVC, P = 0.199; LVCΔpeak, P = 0.904; LVCAUC, P = 0.823). PHEN increased LVC at rest and throughout PLM in both groups (drug effect: P < 0.05), however LVCΔpeak was only improved in the young (PHEN: 6.4 ± 3.1, PROP: 4.4 ± 1.5 mL·min-1·mmHg-1, P = 0.004), and not in the old (P = 0.904). Furthermore, the magnitude of α-adrenergic modulation (PHEN - PE) of LVCΔpeak was greater in the young compared with the old (Young: 3.35 ± 2.32, Old: 0.40 ± 1.59 mL·min-1·mmHg-1, P = 0.019). Therefore, elevated α-adrenergic tone does not appear to contribute to the attenuated vascular function with age identified by PLM.NEW & NOTEWORTHY Stimulation of α1-adrenergic receptors eliminated age-related differences in passive leg movement (PLM) by decreasing PLM-induced vasodilation in the young. Systemic β-blockade attenuated the central hemodynamic component of the PLM response in young individuals. Inhibition of α-adrenergic receptors did not improve the PLM response in older individuals, though withdrawal of α-adrenergic modulation augmented baseline and maximal vasodilation in both groups. Accordingly, α-adrenergic signaling plays a role in modulating the PLM vasodilatory response in young but not in old adults, and elevated α-adrenergic tone does not appear to contribute to the attenuated vascular function with age identified by PLM.

Transcatheter Arterialization of Deep Veins in Chronic Limb-Threatening Ischemia

BACKGROUND

Approximately 20% of patients with chronic limb-threatening ischemia have no revascularization options, leading to above-ankle amputation. Transcatheter arterialization of the deep veins is a percutaneous approach that creates an artery-to-vein connection for delivery of oxygenated blood by means of the venous system to the ischemic foot to prevent amputation.

METHODS

We conducted a prospective, single-group, multicenter study to evaluate the effect of transcatheter arterialization of the deep veins in patients with nonhealing ulcers and no surgical or endovascular revascularization treatment options. The composite primary end point was amputation-free survival (defined as freedom from above-ankle amputation or death from any cause) at 6 months, as compared with a performance goal of 54%. Secondary end points included limb salvage, wound healing, and technical success of the procedure.

RESULTS

We enrolled 105 patients who had chronic limb-threatening ischemia and were of a median age of 70 years (interquartile range, 38 to 89). Of the patients enrolled, 33 (31.4%) were women and 45 (42.8%) were Black, Hispanic, or Latino. Transcatheter arterialization of the deep veins was performed successfully in 104 patients (99.0%). At 6 months, 66.1% of the patients had amputation-free survival. According to Bayesian analysis, the posterior probability that amputation-free survival at 6 months exceeded a performance goal of 54% was 0.993, which exceeded the prespecified threshold of 0.977. Limb salvage (avoidance of above-ankle amputation) was attained in 67 patients (76.0% by Kaplan-Meier analysis). Wounds were completely healed in 16 of 63 patients (25%) and were in the process of healing in 32 of 63 patients (51%). No unanticipated device-related adverse events were reported.

CONCLUSIONS

We found that transcatheter arterialization of the deep veins was safe and could be performed successfully in patients with chronic limb-threatening ischemia and no conventional surgical or endovascular revascularization treatment options. (Funded by LimFlow; PROMISE II study ClinicalTrials.gov number, NCT03970538.).

Magnetic Resonance Imaging-Derived Microvascular Perfusion Modeling to Assess Peripheral Artery Disease

Background Computational fluid dynamics has shown good agreement with contrast-enhanced magnetic resonance imaging measurements in cardiovascular disease applications. We have developed a biomechanical model of microvascular perfusion using contrast-enhanced magnetic resonance imaging signal intensities derived from skeletal calf muscles to study peripheral artery disease (PAD). Methods and Results The computational microvascular model was used to study skeletal calf muscle perfusion in 56 individuals (36 patients with PAD, 20 matched controls). The recruited participants underwent contrast-enhanced magnetic resonance imaging and ankle-brachial index testing at rest and after 6-minute treadmill walking. We have determined associations of microvascular model parameters including the transfer rate constant, a measure of vascular leakiness; the interstitial permeability to fluid flow which reflects the permeability of the microvasculature; porosity, a measure of the fraction of the extracellular space; the outflow filtration coefficient; and the microvascular pressure with known markers of patients with PAD. Transfer rate constant, interstitial permeability to fluid flow, and microvascular pressure were higher, whereas porosity and outflow filtration coefficient were lower in patients with PAD than those in matched controls (all P values ≤0.014). In pooled analyses of all participants, the model parameters (transfer rate constant, interstitial permeability to fluid flow, porosity, outflow filtration coefficient, microvascular pressure) were significantly associated with the resting and exercise ankle-brachial indexes, claudication onset time, and peak walking time (all P values ≤0.013). Among patients with PAD, interstitial permeability to fluid flow, and microvascular pressure were higher, while porosity and outflow filtration coefficient were lower in treadmill noncompleters compared with treadmill completers (all P values ≤0.001). Conclusions Computational microvascular model parameters differed significantly between patients with PAD and matched controls. Thus, computational microvascular modeling could be of interest in studying lower extremity ischemia.

The impact of leg position on muscle blood flow and oxygenation during low-intensity rhythmic plantarflexion exercise

PURPOSE

Resistance training (RT) is an effective countermeasure to combat physical deconditioning whereby localized hypoxia within the limb increases metabolic stress eliciting muscle adaptation. The current study sought to examine the influence of gravity on muscle oxygenation (SmO₂) alongside vascular hemodynamic responses.

METHODS

In twelve young healthy adults, an ischemic occlusion test and seven minutes of low-intensity rhythmic plantarflexion exercise were used alongside superficial femoral blood flow and calf near-infrared spectroscopy to assess the microvascular vasodilator response, conduit artery flow-mediated dilation, exercise-induced hyperemia, and SmO₂ with the leg positioned above or below the heart in a randomized order.

RESULTS

The microvascular vasodilator response, assessed by peak blood flow (798 ± 231 mL/min vs. 1348 ± 290 mL/min; p < 0.001) and reperfusion slope 10 s of SmO₂ after cuff deflation (0.75 ± 0.45%.s-1 vs.2.40 ± 0.94%.s-1; p < 0.001), was attenuated with the leg above the heart. This caused a blunted dilatation of the superficial femoral artery (3.0 ± 2.4% vs. 5.2 ± 2.1%; p = 0.008). Meanwhile, blood flow area under the curve was comparable (above the heart: 445 ± 147 mL vs. below the heart: 474 ± 118 mL; p = 0.55) in both leg positions. During rhythmic exercise, the increase in femoral blood flow was lower in the leg up position (above the heart: 201 ± 94% vs. below the heart: 292 ± 114%; p = 0.001) and contributed to a lower SmO₂ (above the heart: 41 ± 18% vs. below the heart 67 ± 5%; p < 0.001).

CONCLUSION

Positioning the leg above the heart results in attenuated peak vascular dilator response and exercise-induced hyperemia that coincided with a lower SmO₂ during low-intensity plantarflexion exercise.

Evaluation of the Information Content for Determining the Vascular Tone Type of the Lower Extremities in Varicose Veins: A Case Study

The incidence of cardiovascular diseases is continuously increasing around the world. Therefore, the study of new methods for diagnosing cardiovascular diseases is very important. Early diagnosis and evaluation of the effectiveness of treatments are among the most important tasks. In this work, we study changes in vascular compliance and vascular tone of the lower extremities in a patient diagnosed with an early stage of varicose veins. The study is based on recording the bioimpedance signals of the lower extremities and their parts using the Rheo-32 multichannel device. Registration in the monitoring system takes place in two stages: the first in a state of relaxation, and the second after applying a local massage on one of the legs for five minutes. The results indicate a change in the type of vascular tone of the lower extremities after the massage, while the type of vascular tone changes and shifts on average towards the normotonic type. The method proposed in this study makes it possible to quantitatively and qualitatively assess changes in the tone of the vessels of the extremities.

Distal outpatients hemodynamic treatment of chronic venous insufficiency of the lower limbs: a new proposal

The etiology of the venous insufficiency of the lower limbs is related to the increase of the district pressure. This occurs in case of pressure overload of the afferent compartment with a progressive increase of the gradient until the reversal of the flow direction. Varicose veins would be the effect and not the cause of the pressure overload which must always be researched in the efferent (draining) compartment. The gradient inversion in a compartment causes a reflux circuit (venous shunt) only if - in addition to the escape point - one re-entry point is also active, The closure of the escape point does not solve the etiological moment of the district pressure overload. It is therefore a symptomatic treatment that cannot reduce the potential of the system to cause recurrences. During walking, reflux will cause Transmural Pressure Peaks (PPT): in diastole if the reflux is systolic; in systole if the reflux is diastolic; in diastole and in systole if the reflux is diastolic-systolic. On this basis, it has been proposed CHIVA 2 distal outpatient treatment without CHIVA 1 with interesting haemodynamic effects. In the subcutaneous area by the pressure overload block it improves compartment drainage, reduces the peak of trans-mural pressure and the caliber of the varicose veins. In the intrafascial district: reduces peak and trans-mural walking pressure; does not change the drainage of the reflux; can restore an antegrade flow. KEY WORDS: Hemodyamic venous treatment, Vricose veins, Venous Hemodynamic Map (VHM).

Inspiratory and leg muscle blood flows during inspiratory muscle metaboreflex activation in heart failure with preserved ejection fraction

The purpose of this study was to determine the cardiovascular consequences elicited by activation of the inspiratory muscle metaboreflex in patients with heart failure with preserved ejection fraction (HFpEF) and controls. Patients with HFpEF (n = 15; 69 ± 10 yr; 33 ± 4 kg/m2) and controls (n = 14; 70 ± 8 yr; 28 ± 4 kg/m2) performed an inspiratory loading trial at 60% maximal inspiratory pressure (PIMAX) until task failure. Mean arterial pressure (MAP) was measured continuously. Near-infrared spectroscopy and bolus injections of indocyanine green dye were used to determine the percent change in blood flow index (%ΔBFI) from baseline to the final minute of inspiratory loading in the vastus lateralis and sternocleidomastoid muscles. Vascular resistance index (VRI) was calculated. Time to task failure was shorter in HFpEF than in controls (339 ± 197 s vs. 626 ± 403 s; P = 0.02). Compared with controls, patients with HFpEF had a greater increase from baseline in MAP (16 ± 7 vs. 10 ± 6 mmHg) and vastus lateralis VRI (76 ± 45 vs. 32 ± 19%) as well as a greater decrease in vastus lateralis %ΔBFI (-32 ± 14 vs. -17 ± 9%) (all, P < 0.05). Sternocleidomastoid %ΔBFI normalized to absolute inspiratory pressure was higher in HFpEF compared with controls (8.0 ± 5.0 vs. 4.0 ± 1.9% per cmH2O·s; P = 0.03). These data indicate that patients with HFpEF exhibit exaggerated cardiovascular responses with inspiratory muscle metaboreflex activation compared with controls.NEW & NOTEWORTHY Respiratory muscle dysfunction is thought to contribute to exercise intolerance in heart failure with preserved ejection fraction (HFpEF); however, the underlying mechanisms are unknown. In the present study, patients with HFpEF had greater increases in leg muscle vascular resistance index and greater decreases in leg muscle blood flow index compared with controls during inspiratory resistive breathing (to activate the metaboreflex). Furthermore, respiratory muscle blood flow index responses normalized to pressure generation during inspiratory resistive breathing were exaggerated in HFpEF compared with controls.

Persistent sciatic artery: A case report and literature review

The persistent sciatic artery is an uncommon disease, considered an axial congenital vascular malformation due to the lack of involution of the sciatic artery during embryonic development. It may be associated with abnormalities in the development of the iliac, common femoral and superficial femoral arteries. Patients may be asymptomatic, or they could present chronic pain, such as sciatic neuralgia, caused by nerve damage, since it is close to the abnormal persistent vessel, or due to ischemic pain, as a result of a thrombosis or embolism of an aneurysm, which could compromise the viability of the limb.

Investigating effects of sodium beta-hydroxybutyrate on metabolism in placebo-controlled, bilaterally infused human leg with focus on skeletal muscle protein dynamics

Systemic administration of beta-hydroxybutyrate (BHB) decreases whole-body protein oxidation and muscle protein breakdown in humans. We aimed to determine any direct effect of BHB on skeletal muscle protein turnover when administered locally in the femoral artery. Paired design with each subject being investigated on one single occasion with one leg being infused with BHB and the opposing leg acting as a control. We studied 10 healthy male volunteers once with bilateral femoral vein and artery catheters. One artery was perfused with saline (Placebo) and one with sodium-BHB. Labelled phenylalanine and palmitate were used to assess local leg fluxes. Femoral vein concentrations of BHB were significantly higher in the intervention leg (3.4 (3.2, 3.6) mM) compared with the placebo-controlled leg (1.9 (1.8, 2.1) mM) with a peak difference of 1.4 (1.1, 1.7) mM, p < 0.0005. Net loss of phenylalanine for BHB vs Placebo -6.7(-10.8, -2.7) nmol/min vs -8.7(-13.8, -3.7) nmol/min, p = 0.52. Palmitate flux and arterio-venous difference of glucose did not differ between legs. Under these experimental conditions, we failed to observe the direct effects of BHB on skeletal muscle protein turnover. This may relate to a combination of high concentrations of BHB (close to 2 mM) imposed systemically by spillover leading to high BHB concentrations in the saline-infused leg and a lack of major differences in concentration gradients between the two sides-implying that observations were made on the upper part of the dose-response curve for BHB and the relatively small number of subjects studied.

VENOUS THROMBOEMBOLISM IN THE EMERGENCY DEPARTMENT - SINGLE-CENTER EXPERIENCE

Given the importance of early recognition of acute venous thromboembolism (VTE) and the nonspecificity of its symptoms and signs, it is essential to follow the guidelines for diagnostic and therapeutic decisions. Ultrasound examination of the entire lower extremity is currently the standard diagnostic method for symptomatic patients with a clinical probability of deep vein thrombosis (DVT) according to the Wells scoring system. The aim of this study is to show the demographic structure and analyze the number of patients in the emergency department with suspected venous thrombosis. In the past 10 years, 2,022 patients with DVT and 686 with pulmonary emboli have been diagnosed. Despite adherence to the diagnostic protocol, nearly two-thirds of patients require early ultrasound diagnosis. One-fifth of patients had thrombosis of the superficial venous system of the leg or arm. Thrombus was present in the veins of the lower leg in 37% of patients with DVT. The presence of thrombi above the knee, involving the deep femoropopliteal venous system, was found in as much as one-third of patients. These findings and current guidelines suggest that there is a paradigm shift toward more frequent use of DOAC in patients with DVT. However, greater educational efforts may be needed for many physicians to become comfortable with the use of DOAC in the outpatient management of patient populations at low risk for pulmonary embolism.

Role of Endothelin-1 Receptors in Limiting Leg Blood Flow and Glucose Uptake During Hyperinsulinemia in Type 2 Diabetes

Skeletal muscle insulin resistance is a hallmark of individuals with type 2 diabetes mellitus (T2D). In healthy individuals insulin stimulates vasodilation, which is markedly blunted in T2D; however, the mechanism(s) remain incompletely understood. Investigations in rodents indicate augmented endothelin-1 (ET-1) action as a major contributor. Human studies have been limited to young obese participants and focused exclusively on the ET-1 A (ETA) receptor. Herein, we have hypothesized that ETA receptor antagonism would improve insulin-stimulated vasodilation and glucose uptake in T2D, with further improvements observed during concurrent ETA + ET-1 B (ETB) antagonism. Arterial pressure (arterial line), leg blood flow (LBF; Doppler), and leg glucose uptake (LGU) were measured at rest, during hyperinsulinemia alone, and hyperinsulinemia with (1) femoral artery infusion of BQ-123, the selective ETA receptor antagonist (n = 10 control, n = 9 T2D) and then (2) addition of BQ-788 (selective ETB antagonist) for blockade of ETA and ETB receptors (n = 7 each). The LBF responses to hyperinsulinemia alone tended to be lower in T2D (controls: ∆161 ± 160 mL/minute; T2D: ∆58 ± 43 mL/minute, P = .08). BQ-123 during hyperinsulinemia augmented LBF to a greater extent in T2D (% change: controls: 14 ± 23%; T2D: 38 ± 21%, P = .029). LGU following BQ-123 increased similarly between groups (P = .85). Concurrent ETA + ETB antagonism did not further increase LBF or LGU in either group. Collectively, these findings suggest that during hyperinsulinemia ETA receptor activation restrains vasodilation more in T2D than controls while limiting glucose uptake similarly in both groups, with no further effect of ETB receptors (NCT04907838).

["Slavinorm" - an innovative drug for pathogenetic treatment of obliterating diseases of lower limb arteries. Resolution of the Expert Council of 25.08.2022]

"Slavinorm" - an innovative drug for pathogenetic treatment of obliterating diseases of lower limb arteries. Resolution of the Expert Council of 25.08.2022.

SURGICAL TREATMENT IMMEDIATE RESULTS OF LOWER LIMBS CHRONIC CRITICAL ISCHEMIA IN IMMULTANEOUS DIRECT AND INDIRECT REVASCULARIZATION

OBJECTIVE

The aim: To assess the immediate results of autovenous femoral-tibial shunting in combination with rotary osteotrepanation of the tibia by studying changes in the transcutaneous ptO2 tension in the tibia and foot tissues depending on the revascularization of the tibial arteries.

PATIENTS AND METHODS

Materials and methods: We analyzed the treatment of 69 patients with obliterating atherosclerosis of the vessels of the lower extremities. According to the degree of ischemia of the lower extremities, the patients were distributed as follows: III A degree of ischemia - 20 (29%), III B - 28 (40.6%), IV - 21 (30.4%) patients. All patients had atherosclerotic lesions of the popliteal-tibial segment of the great arteries with preserved central blood flow in the aorto-iliac segment.

RESULTS

Results: Occlusion of the anterior tibial artery was recorded significantly more often than the peroneal artery (72% and 42%, respectively, p = 0.05), but with the same frequency compared to the posterior tibial artery (68%, p = 0.61). The lesion of two or three arteries of the lower leg was recorded more often than occlusion of one (n = 51; 73.9% and n = 18; 26.1%). Occlusive-stenotic lesion of the popliteal artery was observed in 54 (78.2%) patients. The highest incidence of lesions of the tibial arteries was observed in the basin of the anterior tibial artery in 28 (40.6%) patients. Combined lesions of the anterior tibial artery and posterior tibial artery were diagnosed in 19 (27.5%) patients. Limited lesions of the posterior tibial artery were found in 15 (21.7%) patients. The combination of lesions of the posterior tibial artery and peroneal artery was diagnosed in 7 (10.2%) patients.

CONCLUSION

Conclusions: 1. The patency of the femoral-tibial autovenous shunt during the year was 71%. High limb amputation was performed in 29% of patients. 2. According to CT data, the localization of trophic changes on the foot during critical ischemia of the lower extremities corresponds to the affected segment of the arterial angiosome, which supplies the corresponding area with blood. 3. After femoral-tibial autovenous bypass grafting, the highest levels of transcutaneous oxygen tension were observed in the basin of the posterior tibial artery and peroneal artery, and the lowest indicators of transcutaneous oxygen tension were observed in the basin of the anterior tibial artery. 4. During femoral-tibial autovenous shunting operations in combination with rotary osteotrepanation, the transcutaneous oxygen tension indices increased threefold in the angiosomal basin of the posterior tibial artery and peroneal artery, and twofold in the angiosomes of the dorsum of the foot and sole.

Differential effects of sex on adaptive responses of skeletal muscle vasodilation to exercise training in type 2 diabetes

AIMS

We tested the hypotheses that exercise training improves the peak and dynamic responses of leg vascular conductance (LVC) in males and females with type 2 diabetes (T2DM).

METHODS

Forty-one males and females with T2DM were assigned to two training groups and two control groups. Twelve weeks of aerobic/resistance training was performed three times per week, 60-90 min per session. Responses of calf muscle blood flow and systemic arterial pressure during incremental and constant-load (30% maximal voluntary contraction) intermittent plantar-flexion protocols in the supine position were recorded.

RESULTS

Training significantly increased peak LVC in males (4.86 ± 1.88 to 6.06 ± 2.06 ml·min^-1·mm Hg^-1) and females (3.91 ± 1.13 to 5.40 ± 1.38 ml·min^-1·mm Hg^-1) with no changes in control groups. For dynamic responses, training significantly increased the amplitude of the fast growth phase of LVC (1.81 ± 1.12 to 2.68 ± 1.01 ml·min^-1·mm Hg^-1) and decreased the time constant of the slow growth phase (43.6 ± 46.4 s to 16.1 14.0 s) in females, but no improvements were observed in control females or in any of the two male groups.

CONCLUSIONS

These data suggest that training increases the peak vasodilatory response in males and females, whereas the speed of the dynamic response of vasodilation is improved in females but not males.

Green Tea Extract Concurrent with an Oral Nutritional Supplement Acutely Enhances Muscle Microvascular Blood Flow without Altering Leg Glucose Uptake in Healthy Older Adults

Postprandial macro- and microvascular blood flow and metabolic dysfunction manifest with advancing age, so vascular transmuting interventions are desirable. In this randomised, single-blind, placebo-controlled, crossover trial, we investigated the impact of the acute administration of green tea extract (GTE; containing ~500 mg epigallocatechin-3-gallate) versus placebo (CON), alongside an oral nutritional supplement (ONS), on muscle macro- and microvascular, cerebral macrovascular (via ultrasound) and leg glucose/insulin metabolic responses (via arterialised/venous blood samples) in twelve healthy older adults (42% male, 74 ± 1 y). GTE increased m. vastus lateralis microvascular blood volume (MBV) at 180 and 240 min after ONS (baseline: 1.0 vs. 180 min: 1.11 ± 0.02 vs. 240 min: 1.08 ± 0.04, both p < 0.005), with MBV significantly higher than CON at 180 min (p < 0.05). Neither the ONS nor the GTE impacted m. tibialis anterior perfusion (p > 0.05). Leg blood flow and vascular conductance increased, and vascular resistance decreased similarly in both conditions (p < 0.05). Small non-significant increases in brachial artery flow-mediated dilation were observed in the GTE only and middle cerebral artery blood flow did not change in response to GTE or CON (p > 0.05). Glucose uptake increased with the GTE only (0 min: 0.03 ± 0.01 vs. 35 min: 0.11 ± 0.02 mmol/min/leg, p = 0.007); however, glucose area under the curve and insulin kinetics were similar between conditions (p > 0.05). Acute GTE supplementation enhances MBV beyond the effects of an oral mixed meal, but this improved perfusion does not translate to increased leg muscle glucose uptake in healthy older adults.

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.