Calf Muscle Pump Research Articles

Association of Calf Muscle Pump Stimulation With Sleep Quality in Adults.

Prevention of lower extremity fluid pooling (LEFP) is associated with improved sleep quality. Physical activity and compression stockings are non-invasive methods used to manage LEFP, but both are associated with low adherence. Calf muscle pump (CMP) stimulation is an alternative and more convenient approach. Convenience sampling was used to recruit 11 participants between ages 45 and 65 with poor sleep quality. A within-person single-group pre-test-post-test design was used to evaluate changes in sleep quality, daytime sleepiness, and functional outcomes sensitive to impaired sleep as measured by the Pittsburgh Sleep Quality Index (PSQI), Functional Outcomes of Sleep Questionnaire, and Epworth Sleepiness Scale after 4 weeks of CMP stimulation. Statistical analysis included effect size (ES) calculations. After daily use of CMP stimulation, participants demonstrated improvement in overall sleep quality (ES = -.97) and a large reduction in daily disturbance from poor sleep (ES = -1.25). Moderate improvements were observed in daytime sleepiness (ES = -.53) and functional outcomes sensitive to sleepiness (ES = .49). Although causality could not be determined with this study design, these results support further research to determine whether CMP stimulation can improve sleep quality. © 2016 Wiley Periodicals, Inc.

News in Pathogenesis of Chronic Venous Insufficiency

AbstractThis review article is concentrating on the news in the pathophysiology of chronic venous insufficiency (CVD). Despite ongoing progress in understanding the molecular aspects of CVD the exact mechanism of its development remains unclear. Many different factors may play role in the pathogenesis of CVD, including changes in hydrostatic pressure, valvular incompetence, increased capillary permeability, endothelial dysfunction, activation of leukocytes, deep venous obstruction, capillary microthrombosis, ineffective function of calf muscle pump, biochemical and structural changes in the vessel wall, extracellular matrix alteration, and several other mechanisms. A better understanding of the pathophysiology is an important step in the finding of new potential treatment.

A Prospective Cohort Study of Symptomatic Venous Thromboembolic Events in Foot and Ankle Trauma

Category: Trauma Introduction/Purpose: The incidence of Venous Thromboembolism (VTE) and the balance of risks and benefits associated with chemical thromboprophylaxis in foot and ankle trauma are controversial, and much less investigated than in hip and knee surgery. A recent systematic review showed a low VTE rate in foot and ankle surgery (0-0.55%), but with an increased incidence in foot and ankle trauma, the highest in TA rupture and surgery. This study compares the 90-day VTE rates of 3 cohorts of patients: Group 1: TA ruptures managed in a full weight bearing (FWB), functional, Vacoped™ protocol over an 8 week period; Group 2: Stable ankle fractures managed in NWB below knee casts for 6 weeks; Group 3: Unstable or displaced ankle fractures managed with surgery and NWB below knee casts for 6 weeks. Methods: The data was extracted from two prospectively collected databases, one for the acute TA ruptures between March 2010 and December 2014, and one for ankle fractures from October 2013 to April 2014. These datasets were cross validated with the hospital VTE database. All patients were risk assessed at the time of presentation to the hospital. Selective chemical thromboprophylaxis was prescribed for patients with the previous history of VTE and patients who were deemed high-risk on VTE assessment. 90-day incidence of symptomatic VTE was drawn from the hospital radiology database. Results: Group 1: Overall VTE rate of 4.9% at a mean of 16.1 days. 3 Pulmonary Embolism (PE) and 11 Deep Vein Thrombosis (DVT). Total number of 283 patients. Group 2: Overall VTE rate of 2.2% at a mean of 33.4 days. 5 DVT. Total number of 227 patients Group 3: Overall VTE rate of 3.0% at a mean of 37.2 days. 1 PE and 5 DVT. Total number of 199 patients. Symptomatic VTE presents significantly earlier in acute TA rupture than ankle fracture patients (p=0.002) Conclusion: Although the overall incidence of VTE in foot and ankle trauma is low., there is a relatively higher incidence of VTE in patients with acute TA ruptures. This is, in spite of recent early weight bearing regimens. This study also shows that occurrence of symptomatic VTE in patients with Acute TA rupture happens much sooner compared to the ankle fracture patients. Although the exact reason for this difference in time of presentation of VTE is unknown, it may be due to de-functioning of the calf muscle pump immediately after the acute TA rupture.

The efficiency of O-(beta-hydroxyethyl)-rutosides in reducing the incidence of superficial venous insufficiency in patients with calf muscle pump dysfunction.

Objective We aimed to evaluate the efficiency of O-(beta-Hydroxyethyl)-rutosides (Oxerutin) in reducing the incidence of venous system disease among patients with calf muscle pump dysfunction secondary to immobilization due to lower-limb fractures. Methods A total of 60 patients with lower-limb fractures and immobilized in plaster casts were included in this study randomized into control (n = 30; mean: 30.37 ± 6.03 years; 73.3% males; no treatment) and experiment (n = 30; mean: 31.67 ± 4.76 years; 66.6% males; Oxerutin, 500 mg po q12hr) treatment groups. Doppler ultrasound was performed to evaluate the effect of oxerutin on the alterations in the venous circulation. Results Patients in the control group were determined to be more commonly affected from the below-knee immobilization in terms of venous dysfunction in the great saphenous vein in the below-knee region when compared with the patients in the oxerutin treatment group (46.7 vs. 13.3%, respectively; p = 0.011). Incidence of reflux in the small saphenous vein was more common in the control group during the healing period when compared with the experiment group (40.0 vs. 10.0%, respectively; p = 0.017). None of the patients developed venous thrombosis. Conclusions In conclusion, the impairment of the lower extremity muscle pump should be considered as an important risk factor for venous disease, and should be evaluated. O-(beta-Hydroxyethyl)-rutosides during 6-8 week cast immobilization for a lower limb fracture may be an effective prophylactic regimen in reducing the incidence of reflux in the below-knee superficial veins.

The value of near-infrared spectroscopy for the assessment of calf muscle function in venous patients.

Near-infrared spectroscopy (NIRS) is a noninvasive technique with the potential to determine the degree of tissueoxygenation. The aim of the current study was to investigate the use of NIRS as a reliable method of detecting calf muscle pump dysfunction in groups of patients with venous disease. Patients with superficial venous insufficiency (SVI) orhistory of deep venous thrombosis (DVT) were classified according to the comprehensive classification system for chronic venous disorders (clinical class, etiology, anatomy, andpathophysiology) and compared with controls (GROUP variable). A 10-stage evaluation of ambulatory venous function was performed, and corresponding values of calf regional oxygen saturation (crSaO2, %) at each phase were recorded (TIME variable). Thereafter, the percentage changes of crSaO2 values (Δ scores, %) between a given phase and the reference phase were estimated. Differences among groups and phases were evaluated using analysis of variance. Subgroup analysis between C0-C2 and C3-C6 patients was performed. The receiver operating characteristic curve analysis was used todetect the best predictive capability for SVI and DVT. A total of 30 patients with SVI, 31 patients with DVT, and 34 controls were included in the study. A statistically significant effect of TIME (F= 382.4; P< .001) andTIME×GROUP interaction (F= 6.3; P< .001) was recorded. Concerning prediction, we found a statistically significant area under the curve (AUC) for SVI (AUC= 0.72; 95% confidence interval, 0.58-0.83; P= .003) and forDVT (AUC= 0.83; 95% confidence interval, 0.71-0.92; P< .0001) patients. The measurement of crSaO2 using NIRS detected alterations in calf muscle pump oxygenation during exercise and differences in tissue oxygenation among SVI patients, DVT patients, and controls. NIRS may represent a reliable noninvasive tool for the study of calf muscle dysfunction in venous disease and a useful vehicle for generating testable hypotheses in the laboratory setting.

Evaluating the effectiveness of a self-management exercise intervention on wound healing, functional ability and health-related quality of life outcomes in adults with venous leg ulcers: a randomised controlled trial.

Exercise that targets ankle joint mobility may lead to improvement in calf muscle pump function and subsequent healing. The objectives of this research were to assess the impact of an exercise intervention in addition to routine evidence-based care on the healing rates, functional ability and health-related quality of life for adults with venous leg ulcers (VLUs). This study included 63 patients with VLUs. Patients were randomised to receive either a 12-week exercise intervention with a telephone coaching component or usual care plus telephone calls at the same timepoints. The primary outcome evaluated the effectiveness of the intervention in relation to wound healing. The secondary outcomes evaluated physical activity, functional ability and health-related quality of life measures between groups at the end of the 12 weeks. A per protocol analysis complemented the effectiveness (intention-to-treat) analysis to highlight the importance of adherence to an exercise intervention. Intention-to-treat analyses for the primary outcome showed 77% of those in the intervention group healed by 12 weeks compared to 53% of those in the usual care group. Although this difference was not statistically significant due to a smaller than expected sample size, a 24% difference in healing rates could be considered clinically significant. The per protocol analysis for wound healing, however, showed that those in the intervention group who adhered to the exercise protocol 75% or more of the time were significantly more likely to heal and showed higher rates for wound healing than the control group (P = 0·01), that is, 95% of those who adhered in the intervention group healed in 12 weeks. The secondary outcomes of physical activity, functional ability and health-related quality of life were not significantly altered by the intervention. Among the secondary outcomes (physical activity, functional ability and health-related quality of life), intention-to-treat analyses did not support the effectiveness of the intervention. However, per protocol analyses revealed encouraging results with those participants who adhered more than 75% of the time (n = 19) showing significantly improved Range of Ankle Motion from the self-management exercise programme (P = 0·045). This study has shown that those participants who adhere to the exercise programme as an adjunctive treatment to standard care are more likely to heal and have better functional outcomes than those who do not adhere to the exercises in conjunction with usual care.

The clinical importance of air plethysmography in the assessment of chronic venous disease.

Air plethysmography is a non-invasive test that can quantify venous reflux and obstruction by measuring volume changes in the leg. Its findings correlate with clinical and hemodynamic measures. It can quantitatively assess several components of venous hemodynamics: valvular reflux, calf muscle pump function, and venous obstruction. Although clinical uses of air plethysmography have been validated, it is used almost exclusively for medical research. Air plethysmography can be used to assess chronic venous disease, to evaluate improvement after venous surgery, to diagnose acute and past episodes of deep venous thrombosis, to evaluate compression stocking therapy, to study the physiological implications of high-heeled shoes in healthy women, and even to evaluate the probability of ulcer healing.

Supervised exercise training as an adjunctive therapy for venous leg ulcers: study protocol for a randomised controlled trial.

BackgroundVenous leg ulcers are common, chronic wounds that are painful and reduce quality of life. Compression therapy is known to assist in the healing of venous leg ulceration. Supervised exercise training that targets an improvement in calf muscle pump function might be a useful adjunctive therapy for enhancing ulcer healing and other aspects of physical and mental health. However, the evidence of exercise for individuals with venous ulcers is sparse. Here, we describe the protocol for a study that aims to assess the feasibility of undertaking a randomised controlled trial of a supervised exercise programme in people who are receiving compression for venous ulceration.Methods/DesignThis is a randomised, controlled, assessor-blinded, two-centre, feasibility trial with two parallel groups. Eighty adults who are receiving lower-limb compression for a venous leg ulcer will be randomly assigned to receive usual care (compression only) or usual care plus a 12-week supervised exercise programme. Participants in the exercise group will be invited to undertake three, 60-minute sessions of supervised exercise each week, and each session will involve a combination of treadmill walking, upright cycling and strength and flexibility exercises for the lower limbs. Participants will be assessed before randomisation and 3, 6 and 12 months after randomisation. Primary outcomes include rates of recruitment, retention and adherence. Secondary outcomes include time to ulcer healing, proportion of participants healed, percentage and absolute change in ulcer size, health-related quality of life (EQ-5D-5L and VEINES-QOL/Sym), lower-limb cutaneous microvascular function (laser Doppler flowmetry coupled with iontophoresis) and physical fitness (30-second sit-to-stand test, chair sit and reach test, 6-minute walk test and ankle range of motion). The costs associated with the exercise programme and health-care utilisation will be calculated. We will also complete interviews with a sub-sample of participants to explore their experiences of having a venous ulcer and the acceptability of the exercise intervention and study procedures.DiscussionData from this study will be used to refine the supervised exercise programme, investigate the acceptability of the intervention and study design and determine the most appropriate outcome measures, thereby providing estimates of the factors needed to design an adequately powered trial across several centres.Trial registrationCurrent Controlled Trials, ISRCTN10205425 (May 2014) - http://www.controlled-trials.com/ISRCTN10205425 Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-015-0963-z) contains supplementary material, which is available to authorized users.

Management of Venous Stasis Ulcers in the Older Adult

Venous stasis disease is common among older adults due to calf muscle pump failure, immobility, chronic edema, and obesity. Increased venous pressure increases the capillaries’ permeability allowing fluid, proteins, and blood cells to leak into the tissues. Ulceration is precipitated by reduced oxygen diffusion to the skin and microvasculature damages. While most chronic leg ulcers are caused by venous stasis disease, there is a need to rule out other underlying pathologies including arterial, neuropathic, metabolic, hematological, infectious, malignant, and inflammatory diseases. Compression therapy with high stiffness index is the mainstay of treatment for venous leg ulcers. Adherence to compression therapy could be a challenge in the older population due to reduced dexterity, muscle strength, range of motion, and flexibility. Medications such as pentoxifylline, flavonoids, and zinc have been shown to have a positive role in the management of venous disease.

A 1D pulse wave propagation model of the hemodynamics of calf muscle pump function.

The calf muscle pump is a mechanism which increases venous return and thereby compensates for the fluid shift towards the lower body during standing. During a muscle contraction, the embedded deep veins collapse and venous return increases. In the subsequent relaxation phase, muscle perfusion increases due to increased perfusion pressure, as the proximal venous valves temporarily reduce the distal venous pressure (shielding). The superficial and deep veins are connected via perforators, which contain valves allowing flow in the superficial-to-deep direction. The aim of this study is to investigate and quantify the physiological mechanisms of the calf muscle pump, including the effect of venous valves, hydrostatic pressure, and the superficial venous system. Using a one-dimensional pulse wave propagation model, a muscle contraction is simulated by increasing the extravascular pressure in the deep venous segments. The hemodynamics are studied in three different configurations: a single artery–vein configuration with and without valves and a more detailed configuration including a superficial vein. Proximal venous valves increase effective venous return by 53% by preventing reflux. Furthermore, the proximal valves shielding function increases perfusion following contraction. Finally, the superficial system aids in maintaining the perfusion during the contraction phase and reduces the refilling time by 37%. © 2015 The Authors. International Journal for Numerical Methods in Biomedical Engineering published by John Wiley & Sons Ltd.

Effect of physical therapy on wound healing and quality of life in patients with venous leg ulcers: a systematic review.

Patients with venous leg ulcers (VLUs) have calf muscle pump dysfunction, which is associated with reduced ankle range of motion (ROM). Physical therapy or exercise that targets ankle joint mobility may lead to improvement in calf muscle pump function and subsequent healing. However, little is known regarding the effect of physical therapy or exercise on healing and quality of life (QOL), which is impaired in patients with VLUs. To systematically review the current literature on the effect of physical therapy on healing and QOL outcomes in patients with VLUs and to identify research gaps that warrant further investigation. PubMed (MEDLINE), CINAHL, and Cochrane databases were searched in April 2014. We found 10 articles, consisting of randomized clinical trials and single-arm cohort studies with small sample sizes, that used physical therapy or exercise for patients with open or healed VLUs. Although there is evidence that exercise strengthens the calf muscle pump and improves ankle ROM, few studies have investigated the effect of these interventions on QOL and healing, and few involved the supervision of a physical therapist. The lack of evidence and randomized clinical trials suggests the need for further investigation on physical therapy-oriented exercise on wound healing and QOL. In addition, more studies are needed to investigate sustainability of the increased ankle ROM after physical therapy has ended or if VLU reoccurrences are prevented.

A hemodynamic study of the effect of neuromuscular electrical stimulation on enhancing popliteal venous flow

Neuromuscular electrical stimulation has been studied to be a method of prophylaxis for deep venous thrombosis by activating the calf muscle pump. However, there is little evidence of the effects of different stimulating parameters on hemodynamics and comfort levels. The objective of this paper is to compare the effects of different stimulating parameters (current amplitude, pulse-width) on hemodynamic alterations of the popliteal vein and the comfort levels in a group of fourteen healthy subjects. Doppler ultrasound detection of peak venous velocity and blood volume were taken from baseline, twelve sequential electrical stimulations and foot dorsiflexion for each subject. A visual analogue scale was used to assess the subjects’ pain perception of neuromuscular electrical stimulation. The results showed that peak venous velocity and blood volume augmented as current amplitude and pulse-width increased while pain level also increased. A compromise was reached that parameters consisting of an amplitude of 10mA and a pulse-width of 500 μs would obtain a high-peak venous velocity and blood flow volume with a relatively comfortable perception. In addition, parameters consisting of an amplitude of 20mA and a pulse-width of 300 μs were also shown to be a promising choice. However, further studies need to be done to validate and enrich these findings.

Calf muscle pump stimulation as a means to reduce symptoms of fibromyalgia syndrome.

Fibromyalgia (FM) is a debilitating chronic condition that often affects women in midlife with widespread pain that interrupts attempts to exercise. The purpose of this pilot study was to test the efficacy of calf muscle pump (CMP) stimulation as an adjuvant therapy for FM by (1) assessing the correlation of the level of symptoms, as measured by the revised Fibromyalgia Impact Questionnaire (FIQR), and blood pressure (BP), (2) measuring change in mean FIQR scores for subjects who use a CMP-stimulation device for 12 weeks, and (3) measuring the correlation of total device usage and the level of symptoms as measured by the FIQR. The 29 male and female participants (mean age = 47.3 years) were screened using the Widespread Pain Index (WPI), Symptom Severity (SS) score, and the FIQR. Participants were contacted weekly, and progress was assessed using the WPI, SS score, and the FIQR as well as general questions regarding responses to CMP stimulation. The attrition rate was high, which is not uncommon in studies of patients with FM. We found that diastolic BP was significantly inversely correlated with baseline FIQR scores during quiet sitting. Further, 12 weeks of CMP stimulation was associated with significant improvement in average FIQR scores at a rate of approximately -1.5 points per week (R (2) = .9; p ≤ .0001). Total device usage was strongly and inversely correlated with baseline FIQR scores (R (2) = .43; p = .02). These findings suggest that CMP stimulation may provide an additional treatment option for individuals with FM who are challenged to perform traditional forms of exercise.

The effect of ankle range of motion on venous ulcer healing rates.

Limitation of ankle movement may contribute to calf muscle pump failure, which is thought to contribute to venous leg ulcer formation, which affects nearly 1 million Americans. We therefore wished to study ankle movement in patients with venous leg ulcers and its effect on healing. Using goniometry, we measured baseline ankle range of motion in venous leg ulcer patients from a Phase 2 dose-finding study of an allogeneic living cell bioformulation. Two hundred twenty-seven patients were enrolled in four active treatment groups and one standard-care control group, all receiving compression therapy. Goniometry data from a control group of 49 patients without venous disease, from a previous study, was used for comparison. We found patients with active venous leg ulcers had significantly reduced ankle range of motion compared with the control group (p = 0.001). After 12 weeks of therapy, baseline ankle range of motion was not associated with healing, as there was no significant difference between healed and nonhealed groups, suggesting that ankle range of motion is not important in venous leg ulcer healing or, more likely, is overcome by compression. However, patients with venous ulcers located on the leg (as opposed to the ankle) had significantly higher ankle range of motion for plantar flexion and inversion (p = 0.021 and p = 0.034, respectively) and improved healing with both cell bioformulation and standard care (p = 0.011), suggesting that wound location is an important variable for ankle range of motion as well as for healing outcomes.

The use of ultrasound in the evaluation of the efficacy of calf muscle pump function in primary chronic venous disease

To evaluate popliteal vein blood flow during calf muscle contraction in chronic venous disease (CVD) patients and healthy controls using ultrasound imaging and to investigate the relationship between venous blood flow and gastrocnemius muscle (GM) morphology. Thirty-one subjects participated in this study (mean age: 40.3 [11.8] years), 15 healthy controls and 16 with CVD (clinical classification: C₁₋₄). Popliteal vein cross-sectional area and venous blood flow velocity (FV) were evaluated by Doppler ultrasound at baseline and during three sets of 10 tip-toe movement repetitions. Muscle thickness, muscle fascicle length and pennation angle of both medial and lateral GM were measured by ultrasound. Measures were repeated a week later in 17 participants in order to assess reproducibility with intraclass correlation coefficient (ICC) and Bland-Altman analysis. Peak FV was lower in CDV group compared with Control group for both first (40.6 [11.8] versus 62.4 (22.1) cm²/second; P = 0.021) and last (30.4 [9.1] versus 49.5 (22.7) cm²/second; P = 0.024) contraction. In CVD group, peak FV during first contraction increased with GM's muscle fascicle length (r = 0.63; P = 0.041). Popliteal FV also increased with rising range of muscle fascicles pennation change between ankle dorsiflexion and plantar flexion (r = 0.70; P = 0.025). No associations were found between haemodynamics and medial or lateral GM thickness. Calf muscular architecture was similar in both CVD and control participants. Test-retest reliability of FV measured in the same session was high (ICC≈0.70) for measures taken in the first contraction of the set but lowered when using the last contraction (ICC<0.50). Reproducibility of ultrasound evaluation of calf pump is acceptable within the same session but is unsatisfactory when testing in separate days. Patients with moderate CVD have lower FV during calf muscles contraction but similar muscle anatomical characteristics compared with healthy controls. Changes in calf muscles flexibility and fatigue resistance may be investigated as possible causes of calf pump dysfunction.

The Effect of Lower Limb Cast Immobilization on Calf Muscle Pump Function

We have investigated the role of the calf muscle pump in casted patients. An audit of venous thromboembolism (VTE) in casted patients showed that the thrombosis occurred in the casted leg; this has not been previously assessed. We postulated that local factors play a major role, and we set out to assess the calf muscle pump in casted patients and to determine whether this can be optimized despite below-knee cast immobilization. We measured the flow in the popliteal vein using a validated method of Doppler ultrasound measurement of peak velocity with and without a below-knee plaster cast. We demonstrated that a simple strategy of toe and ankle exercises can maintain venous return despite below-knee cast immobilization. This is the first study to examine the effect of the calf muscle pump in the presence of a plaster cast. Major muscle groups such as the flexor hallucis longus and gastrocsoleus extend beyond the field of control of the cast and can still be recruited. We recommend that all patients treated with a below-knee cast be given a program of exercises that can be comfortably performed with the cast; this could provide a useful, inexpensive, and safe thromboprophylaxis strategy acting at the site of greatest risk and targeting a major cause of VTE.

Neuropathy and Ankle Mobility Abnormalities in Patients With Chronic Venous Disease

How complications associated with chronic venous insufficiency (CVI) develop is not clear. The central source of the complications is likely a dysfunction of the calf muscle pump, which includes veins and their valves, the gastrocnemius and other lower leg and foot muscles as well as the nerves supplying the muscles, and ankle mobility limitations. The least well-studied source of complications is the relationship between range of ankle movement (ROAM), neuropathy, and the clinical severity of the disease. To study sensory neuropathic changes and ankle mobility in patients with CVI to help elucidate the pathophysiologic development of venous ulcers. A cross-sectional study took place from August 2011 to August 2012 at the outpatient wound clinic and the wound healing research clinic at the University of Miami Hospital. Sixty-four limbs from 42 individuals were evaluated and individually classified according to the clinical aspect of the clinical-etiology-anatomy-pathophysiology classification for CVI. Range of ankle movement was measured using goniometry, measuring active ankle combined plantarflexion and dorsiflexion and combined inversion and eversion. Peripheral neuropathy was measured subjectively through the Neuropathy Symptom Score and objectively through the Neuropathy Disability Score scales. More patients with severe CVI had reduced plantarflexion-dorsiflexion ROAM compared with patients with mild CVI (25 [89%] vs 11 [31%]; P < .001) and reduced inversion-eversion ROAM (22 [79%] vs 4 [11%]; P < .001). Patients with worse CVI had significantly worse neuropathy with higher Neuropathy Symptom Score and Neuropathy Disability Score values compared with patients with less severe CVI. We found a relationship between reduced ROAM and worse neuropathy with increased severity of CVI. Management in patients with CVI should include testing for neuropathy and improving ankle mobility.

The calf muscle pump revisited.

Chronic venous disease (CVD) defines the spectrum of manifestations of venous disease that originate as a result of ambulatory venous hypertension. Thus far, the role of the calf muscle pump in the development and potentiation ofCVD has been overlooked and understated in the clinical setting, with much greater emphasis placed on reflux and obstruction. The aim of this review is to explore the level of significance that calf muscle pump function or dysfunction bears on the development and potentiation of CVD. EMBASE and MEDLINE databases were searched with keywords "calf" AND "muscle" AND "pump" AND "venous" AND "insufficiency" AND ("lower limb*" OR "leg*"), screened for cross-sectional and longitudinal studies relating to chronic venous insufficiency, highlighting the role of the calf muscle pump in CVD and the extent to which the calf muscle pump is impaired in these cases. This resulted in the inclusion of 10 studies. Compared with healthy subjects, patients with CVD have a reduced ejection fraction (15.9%; P< .001) and an increased venous filling index (4.66mL/s; P< .001), indicating impairment in calf muscle pump ejection ability as well as poor venous competence. Calf muscle pump dysfunction is present in 55% of patients with CVD in the literature, but this did not reach significance on meta-analysis. Isotonic exercise programs in patients with active and healed ulcers have been shown to increase calf muscle pump function but not venous competence. Calf muscle pump failure is a therapeutic target inthe treatment of CVD. Evidence suggests that isotonic exercise treatment may be an effective method of increasing the hemodynamic performance of the calf muscle pump. This review emphasizes the requirement for more attention to be placed on the treatment of calf muscle pump failure in cases of CVD by use of exercise treatment programs or other methods, which may be of clinical importance in managing symptomatic disease. To establish this in routine clinical practice, these results would need to be replicated in appropriate clinical trials. It would also be logical to look at other modifiable muscle pumps, such as thethigh and foot, and to explore the potential benefit of electrical devices acting on the leg (eg, electrical muscular orneuromuscular stimulation), especially for those patients in whom exercise capacity is limited.

Measurements of calf muscle oxygenation during standing and exercise in patients with primary valvular insufficiency.

Despite the established role of the calf muscle pump for preventing chronic venous disorders, hemoglobin flow in the calf muscle is poorly understood. Near-infrared spectroscopy (NIRS) provides continuous noninvasive monitoring of changes in tissue-oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) levels. The purpose of this study was to investigate the changes in calf muscle O2Hb and HHb levels during standing and exercise in patients with primary valvular insufficiency (PVI). Eighty-three limbs in 81 patients with PVI were enrolled. The clinical manifestations of these patients were categorized according to the CEAP (Clinical, Etiologic, Anatomical, and Pathophysiologic) classification, and patients were divided into group I (C1-3S,Ep,As,d,p,Pr) and group II (C4-6S,Ep,As,d,p,Pr). Moreover, to assess the severity of PVI, the revised Venous Clinical Severity Score (VCSS) was employed. NIRS was used to measure changes in the calf muscle O2Hb and HHb levels. On standing, increases in O2Hb and HHb were calculated by subtracting the baseline value from the maximum value (ΔO2Hbst and ΔHHbst). The time elapsed until the maximum increases in O2Hb and HHb concentrations (TO2Hbst, and THHbst) were also measured. During 10 tiptoe movements, the relative change in O2Hb was calculated by subtracting the value measured at the end of exercise from the value measured at the beginning of exercise(ΔO2Hbex). On the other hand, 10 tiptoe movements produced venous expulsion (ΔHHbEex) and a subsequent retention (ΔHHbRex). The oxygenation index (HbD; HbD= O2Hb- HHb) was also calculated at the end of standing and10 tiptoe movements (ΔHbDst and ΔHbDex). Among the 83 limbs evaluated, 48 were classified as group I and 35 as group II. Standing caused increases in the levels of both ΔO2Hbst and ΔHHbst. However, there were nosignificant differences in these increases between the two groups. In contrast, the TO2Hbst was significantly reduced in group II in comparison with group I (55± 29 vs 36± 30 seconds; P= .007). During 10 tiptoe movements, a decrease in O2Hb concentration was observed, and there was no significant difference in ΔO2Hbex between group I and group II. In contrast, the ΔHHbRex was significantly increased in group II compared with group I (6± 7 vs 9± 6 μmol/L; P= .013). Furthermore, falls in ΔHbDex were more pronounced in group II (7± 16 vs-7± 16 μmol/L; P= .001). A statistically significant correlation was found between C of CEAP and the VCSS (r= 0.778; P< .001). Moreover, NIRS-derived TO2Hbst (r=-0.312; P< .01) and ΔHbDex (r=-0.332; P< .01) showed moderate inverse correlationswith C of CEAP. Similarly, NIRS-derived ΔHbDex (r=-0.501; P< .001) had a strong inverse correlation, and ΔHbDst (r=-0.383; P< .001) and TO2Hbst (r=-0.378; P< .001) had moderate inverse correlations with VCSS. Changes in O2Hb and HHb concentrations differ according to CEAP manifestation and VCSS. These data offer new insights into calf muscle hemodynamics at the microcirculation level in patients with PVI.

Abstract 337: Measurements of Calf Muscle Oxygenation During Standing and Exercise in Patients with Chronic Venous Insufficiency

BACKGROUND Despite the established role of the calf muscle pump for preventing chronic venous insufficiency (CVI), hemoglobin flow in the calf muscle is poorly understood. Near-infrared spectroscopy (NIRS) provides continuous noninvasive monitoring of changes in tissue oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb) levels. The purpose of this study was to investigate the changes in calf muscle HbO2 and HHb levels during standing and exercise in patients with CVI. METHODS Seventy-four limbs in 73 patients with various clinical stages of CVI were enrolled. Patients were divided into early (C0-C3) and advanced (C4a-C6) according to the CEAP classification. NIRS was used to measure changes in the calf muscle HbO2 and HHb levels, and oxygenation index (HbD; HbD=O2Hb-HHb) while lying spine, standing, and then subsequently performing 10 tiptoe movements. RESULTS Among the 74 limbs evaluated, 47 had early and 27 had advanced CVI. Standing caused increases in both O2Hb and HHb levels. However, there were no significant differences in these increases, or HbD, between early and advanced CVI. In contrast, the time elapsed until the maximum increase in O2Hb concentration was significantly reduced in patients with advanced CVI in comparison with patients showing early CVI (55.5 ± 44.2, 32.6 ± 12.6 s, P=.025). During 10 tiptoe movements, a decrease in O2Hb concentration was observed, and there was no significant difference in the reduction of O2Hb values between early and advanced CVI. In contrast, 10 tiptoe movements produced venous emptying (HHbE) and subsequent retention (HHbR), and the HHbR was significantly increased in patients with advanced CVI compared with those with early CVI (6.0 ± 7.0, 9.0 ± 6.2 μmol/L, P=0.021). Furthermore, HbD falls were more pronounced in patients with advanced CVI (7.4 ± 11.5, -5.9 ± 15.7 μmol/L, P=0.002). CONCLUSIONS Changes in O2Hb and HHb concentrations differ between early and advanced CVI during standing and exercise. Detailed investigation of the interrelationship between O2Hb and HHb during calf muscle pump function would lead to a better understanding of the various clinical stages of CVI.