Improving walking ability and ankle brachial pressure indices in symptomatic peripheral vascular disease with intermittent pneumatic foot compression: a prospective controlled study with one-year follow-up

Comparison of intermittent pneumatic compression device and compression stockings for workers with leg edema and pain after prolonged standing: a prospective crossover clinical trial

BACKGROUND

During prolonged standing, insufficient calf muscle pumping accompanies venous stasis and hypertension in the lower legs, resulting in valve dysfunction, venous wall problems, and sub-sequent inflammation. Compression therapy, which includes medical compression stockings (MCS) and mechanical intermittent pneumatic compression (IPC), is one of the most effective therapeutic interventions for treating chronic venous diseases. This study aimed to compare the therapeutic effect among resting, IPC and MCS alone, and IPC with MCS in long-standing workers (> 8 h daily).

METHODS

This crossover trial was conducted with 39 participants with complaints of leg edema and pain whose work involved standing for more than 8 h daily. Four treatment protocols were established for each visit as follows: protocol A (not wear MCS during work and rest without IPC after work), protocol B (wear MCS during work and rest without IPC after work), protocol C (not wear MCS during work and treat with IPC after work), and protocol D (wear MCS during work and treat with IPC after work). The primary outcome was the visual analogue scale (VAS) score for leg pain. The secondary outcomes were leg volume (mL), circumference (cm), extracellular fluid/total body fluid (ECF/TBF), and extracellular water/total body water (ECW/TBW) through bioelectrical impedance analysis. Outcomes were assessed before work (T0), after work (T1), and 60 min after intervention (T2).

RESULTS

All four protocols had significantly increased leg pain after work (T0-1) but improved 60 min after intervention (T1-2), particularly protocol C (decreased VAS by 1.9). When leg swelling was compared at T0 and T1, protocols A and C showed significant increases in leg volume and circumference, indicating significant work-induced edema, whereas protocols B and D showed no change or even a decrease. After interventions, leg volume and circumference significantly decreased in protocols A and C, although protocols B and C did not show significant improvement. The ECF/TBF and ECW/TBW of all protocols decreased after interventions.

CONCLUSIONS

Leg pain and edema after prolonged standing (T1-T2) in adults were safely and effectively improved by both IPC alone and IPC with MCS. Although the use of MCS during the workday did not show improvement in leg pain immediately after work (T0-T1), both MCS with resting and MCS with IPC decreased leg pain at T1-T2 and prevented leg edema at T0-T1.

TRIAL REGISTRATION

This trial protocol was registered at the Clinical Research Information Service (KCT0005383, the date of first registration: 08/09/2020).

A systematic review of lower extremity electrical stimulation for treatment of walking impairment in peripheral artery disease

Lower extremity peripheral artery disease (PAD) induces an ischemic pain in the lower limbs and leads to walking impairment. Electrical stimulation has been used in patients with PAD, but no systematic review has been proposed to address the efficacy of the technique as a treatment for walking impairment in PAD. A systematic search was performed to identify trials focused on electrical stimulation for the treatment of walking impairment in patients with PAD in the Cochrane Central Register, PubMed, Embase, and the Web of Science. Studies were included where the primary outcomes were pain-free walking distance and/or maximal walking distance. When appropriate, eligible studies were independently assessed for quality using the Cochrane Collaboration's tool for assessing risk of bias. Five studies eligible for inclusion were identified, of which only two were randomized controlled studies. Trial heterogeneity prevented the use of the GRADE system and the implementation of a meta-analysis. Three types of electrical stimulation have been used: neuromuscular electrical stimulation (NMES, n = 3), transcutaneous electrical stimulation (n = 1), and functional electrical stimulation (n = 1). The two available randomized controlled studies reported a significant improvement in maximal walking distance (+40 m/+34% and +39 m/+35%, respectively) following a program of NMES. Owing to the low number of eligible studies, small sample size, and the risk of bias, no clear clinical indication can be drawn regarding the efficacy of electrical stimulation for the management of impaired walking function in patients with PAD. Future high-quality studies are required to define objectively the effect of electrical stimulation on walking capacity.

Effects of Intermittent Pneumatic Compression on Leg Vascular Function in People with Spinal Cord Injury: A Pilot Study

Objective: The purpose of this pilot study was to determine whether 60 mins of intermittent pneumatic compression therapy (IPC) could acutely increase leg blood flow-induced shear stress and enhance vascular endothelial function in persons with spinal cord injury (SCI). Design: Pretest with multiple posttests, within subject randomized control design. Setting: University of Southern Mississippi, Spinal Cord Injury Research Program within the School of Kinesiology, recruiting from the local community in Hattiesburg, Jackson, and Gulfport, MS. Participants: Eight adults with SCI (injury level: T3 and below; ASIA class A-C; age: 41±17 yrs). Interventions: A 60-min IPC session was performed in one leg (experimental leg; EXP), with the other leg serving as a control (CON). Outcomes Measures: Posterior-tibial artery shear rate (Doppler-ultrasound) was examined at rest, and at 15 and 45 mins during IPC. Endothelial function was assessed using the flow-mediated dilation (FMD) technique, before and after IPC. Results: Resting FMD (mm) was similar between legs at rest. A two-way repeated measures ANOVA (leg x time) revealed that during IPC, peak shear rate increased in the EXP leg (215±137 to 285±164 s^-1 at 15 mins; +39±29%, P = 0.03), with no change occurring in the CON. In addition, FMD significantly increased in the EXP leg (Pre IPC: 0.36±0.14 vs. Post IPC: 0.47±0.17 mm; P = 0.011, d = 0.66), with no change occurring in the CON leg. Conclusion: These preliminary findings suggests that IPC therapy may acutely increase leg shear stress within 15 mins, with a resultant moderate-large improvement in vascular endothelial function after 60 mins in people with SCI.

Superficial femoral artery blood flow with intermittent pneumatic compression of the lower leg applied during walking exercise and recovery

The purpose of this study was to determine if muscle blood flow during walking exercise and postexercise recovery can be augmented through the application of intermittent compression of the lower legs applied during the diastolic phase of the cardiac cycle. Results from four conditions were assessed: no compression (NoComp), compression during walking (ExComp), compression during postexercise recovery (RecComp), and compression applied throughout (AllComp). Superficial femoral artery (SFA) blood flow was measured (Doppler ultrasound) during rest and postexercise recovery. Mean arterial blood pressure (MAP, finger photoplethysmography) was used to calculate vascular conductance as VC = SFA flow/MAP. Near infrared spectroscopy measured changes in oxygenated (O2Hb) and deoxygenated hemoglobin concentration throughout the test. Compression during exercise increased SFA blood flow measured over the first 15 s of postexercise recovery (AllComp: 532.2 ± 123.1 mL/min; ExComp: 529.8 ± 99.2 mL/min) compared with NoComp (462.3 ± 87.3 mL/min P < 0.05) and corresponded to increased VC (NoComp: 4.7 ± 0.9 mL·min−1·mmHg−1 versus ExComp: 5.5 ± 1.0 mL·min−1·mmHg−1, P < 0.05). Similarly, compression throughout postexercise recovery also resulted in increased SFA flow (AllComp: 190.5 ± 57.1 mL/min; RecComp: 158.7 ± 49.1 mL/min versus NoComp: 108.8 ± 28.5 mL/min, P < 0.05) and vascular conductance. Muscle contractions during exercise reduced total hemoglobin with O2Hb comprising ~57% of the observed reduction. Compression during exercise augmented this reduction ( P < 0.05) with O2HB again comprising ~55% of the reduction. Total hemoglobin was reduced with compression during postexercise recovery ( P < 0.05) with O2Hb accounting for ~40% of this reduction. Results from this study indicate that intermittent compression applied during walking and during postexercise recovery enhanced vascular conductance during exercise and elevated postexercise SFA blood flow and tissue oxygenation during recovery.

NEW & NOTEWORTHY Intermittent compression mimics the mechanical actions of voluntary muscle contraction on venous volume. This study demonstrates that compression applied during the diastolic phase of the cardiac cycle while walking accentuates the actions of the muscle pump resulting in increased immediate postexercise muscle blood flow and vascular conductance. Similarly, compression applied during the recovery period independently increased arterial flow and tissue oxygenation, potentially providing conditions conducive to faster recovery.

[S1 guideline on intermittent pneumatic compression (IPC)]

Under the direction of the German Society of Phlebology (Deutsche Gesellschaft für Phlebologie) and in cooperation with other specialist associations, the S1 guideline on intermittent pneumatic compression (IPC) was adopted in January 2018. It replaces the previous guideline from March 2005. The aim of the guideline is to optimize the indication and therapeutic use of IPC in vascular diseases and edema. An extensive literature search of MEDLINE, existing guidelines, and work relevant to the topic was performed. In view of the often methodologically weak study quality with often small numbers of cases and heterogeneous treatment protocols, recommendations can often only be derived from the available data using good clinical practice/expert consensus. Intermittent pneumatic compression is used for thromboembolism prophylaxis, decongestive therapy for edema, and to positively influence arterial and venous circulation to improve clinical symptoms and accelerate ulcer healing in both the outpatient and inpatient care setting. The therapy regimens and devices used depend on the indication and target location. They can be used as outpatient and inpatient devices as well as at home for long-term indications. A target indication is thrombosis prophylaxis. IPC should be used in severe chronic venous insufficiency (stages C4b to C6), in extremity lymphedema as an add-on therapy and in peripheral arterial occlusive disease (PAOD) with stable intermittent claudication or critical ischemia. IPC can be used in post-traumatic edema, therapy-resistant venous edema, lipedema and hemiplegia with sensory deficits and edema. Absolute and relative contraindications to IPC must be taken into account and risks considered and avoided as far as possible. Adverse events are extremely rare if IPC is used correctly. If the indication and application are correct-also as an add-on therapy-it is a safe and effective treatment method, especially for the treatment of the described vascular diseases and edema as well as thrombosis prophylaxis.

Enhanced muscle blood flow with intermittent pneumatic compression of the lower leg during plantar flexion exercise and recovery

This study tested the hypothesis that intermittent compression of the lower limb would increase blood flow during exercise and postexercise recovery. Data were collected from 12 healthy individuals (8 men) who performed 3 min of standing plantar flexion exercise. The following three conditions were tested: no applied compression (NoComp), compression during the exercise period only (ExComp), and compression during 2 min of standing postexercise recovery. Doppler ultrasound was used to determine superficial femoral artery (SFA) blood flow responses. Mean arterial pressure (MAP) and cardiac stroke volume (SV) were assessed using finger photoplethysmography, with vascular conductance (VC) calculated as VC = SFA flow/MAP. Compared with the NoComp condition, compression resulted in increased MAP during exercise [+3.5 ± 4.1 mmHg (mean ± SD)] but not during postexercise recovery (+1.6 ± 5.9 mmHg). SV increased with compression during both exercise (+4.8 ± 5.1 ml) and recovery (+8.0 ± 6.6 ml) compared with NoComp. There was a greater increase in SFA flow with compression during exercise (+52.1 ± 57.2 ml/min) and during recovery (+58.6 ± 56.7 ml/min). VC immediately following exercise was also significantly greater in the ExComp condition compared with the NoComp condition (+0.57 ± 0.42 ml·min^-1·mmHg^-1), suggesting the observed increase in blood flow during exercise was in part because of changes in VC. Results from this study support the hypothesis that intermittent compression applied during exercise and recovery from exercise results in increased limb blood flow, potentially contributing to changes in exercise performance and recovery. NEW & NOTEWORTHY Blood flow to working skeletal muscle is achieved in part through the rhythmic actions of the skeletal muscle pump. This study demonstrated that the application of intermittent pneumatic compression during the diastolic phase of the cardiac cycle, to mimic the mechanical actions of the muscle pump, accentuates muscle blood flow during exercise and elevates blood flow during the postexercise recovery period. Intermittent compression during and after exercise might have implications for exercise performance and recovery.

Collateral artery pathways of the femoral and popliteal artery

BACKGROUND

The role of collateral artery circulation in the lower limb is under debate but clinically relevant, particularly when using covered stents for occlusive disease. Covered stents seem to outperform nitinol stents in extensive disease, but collaterals could be essential in case of acute thrombosis. In the present study, we describe the collateral pathways of the deep and superficial femoral artery (DFA, SFA) and the popliteal artery (PA), observed in human cadavers.

METHODS

Ten fresh frozen cadaver legs were selected. The SFA and DFA were separately cannulated and injected with a different colored latex mixture simultaneously. After curing of the latex, the circulation was dissected thus visualizing the main arteries and their collateral vessels. The process was photographed and recorded, and collateral pathways were analyzed using a standardized vessel segmentation. The upper leg was divided in three regions, that is, the femoral triangle (F), the adductor canal (H), and the popliteal fossa (P) that, in turn, were split in three segments (1, 2, and 3, from proximal to distal).

RESULTS

Overall, 113 collateral vessels were found; 69 originated from the DFA, 34 from the SFA, and 10 from the PA. The majority of collaterals originating from the DFA terminated in the SFA (57%). Fifty-six of 113 collaterals (50%) ended in either the distal adductor channel (H3) or the proximal PA (P1). Another 28 collateral arteries (25%) had their origin in this segment (H3, P1) and mostly connected to the P2 and P3 segments. Forty-three collaterals of the DFA and H3 segment had a direct or indirect connection to below the knee muscles.

CONCLUSIONS

The majority of collaterals originate from the DFA, and the greater part of all collaterals has a connection with the H3-P1 segment. This observation may have clinical implications in the planning of endovascular procedures.

Non-Invasive Management of Peripheral Arterial Disease

BACKGROUND

Peripheral arterial disease (PAD) is common and symptoms can be debilitating and lethal. Risk management, exercise, radiological and surgical intervention are all valuable therapies, but morbidity and mortality rates from this disease are increasing. Circulatory enhancement can be achieved using simple medical electronic devices, with claims of minimal adverse side effects. The evidence for these is variable, prompting a review of the available literature.

METHODS

Embase and Medline were interrogated for full text articles in humans and written in English. Any external medical devices used in the management of peripheral arterial disease were included if they had objective outcome data.

RESULTS

Thirty-one papers met inclusion criteria, but protocols were heterogenous. The medical devices reported were intermittent pneumatic compression (IPC), electronic nerve (NMES) or muscle stimulators (EMS), and galvanic electrical dressings. In patients with intermittent claudication, IPC devices increase popliteal artery velocity (49-70 %) and flow (49-84 %). Gastrocnemius EMS increased superficial femoral artery flow by 140 %. Over 4.5-6 months IPC increased intermittent claudication distance (ICD) (97-150 %) and absolute walking distance (AWD) (84-112 %), with an associated increase in quality of life. NMES of the calf increased ICD and AWD by 82 % and 61-150 % at 4 weeks, and 26 % and 34 % at 8 weeks. In patients with critical limb ischaemia IPC reduced rest pain in 40-100 % and was associated with ulcer healing rates of 26 %. IPC had an early limb salvage rate of 58-83 % at 1-3 months, and 58-94 % at 1.5-3.5 years. No studies have reported the use of EMS or NMES in the management of CLI.

CONCLUSION

There is evidence to support the use of IPC in the management of claudication and CLI. There is a building body of literature to support the use of electrical stimulators in PAD, but this is low level to date. Devices may be of special benefit to those with limited exercise capacity, and in non-reconstructable critical limb ischaemia. Galvanic stimulation is not recommended.

Effects of Intermittent Pneumatic Compression on Reduction of Postoperative Lower Extremity Edema and Normalization of Foot Microcirculation Flow in Patients Undergoing Arterial Revascularization

BACKGROUND In patients with chronic leg ischemia, the beneficial effect of arterial revascularization can be significantly decreased due to postoperative leg swelling. The aim of this study was to assess the effects of intermittent pneumatic compression (IPC) on skin flow normalization in patients undergoing revascularization procedures due to chronic leg ischemia. MATERIAL AND METHODS We evaluated 116 patients with chronic leg ischemia. The patients were divided into groups according to the performed treatment (endovascular or surgical) and implementation of IPC postoperatively. The leg edema assessment and microcirculation flow assessment were performed pre- and postoperatively, using percutaneous O2 pressure (TcpO2), cutaneous blood perfusion (CBP) measurements, and skin flow motion assessment. RESULTS In patients who did not receive IPC, a decrease in CBP value was observed in the 1st postoperative assessment. Among patients receiving IPC, the CBD value increased at the 1st and 2nd postoperative measurements, especially in the surgical group. The lowest TcpO2 values were observed in by-pass surgery group without IPC postoperatively. CONCLUSIONS The benefits of the by-pass procedure in patients with leg ischemia can be significantly reduced by postoperative edema. Among patients with postoperative leg edema, local tissue blood perfusion can be improved by the use of IPC, which can result in decreased local leg swelling, as well as improved skin blood perfusion and TcpO2.

Report from the 2013 meeting of the International Compression Club on advances and challenges of compression therapy

The International Compression Club, a collaboration of medical experts and industry representatives, was founded in 2005 to develop consensus reports and recommendations regarding the use of compression therapy in the treatment of acute and chronic vascular disease. During the recent meeting of the International Compression Club, member presentations were focused on the clinical application of intermittent pneumatic compression in different disease scenarios as well as on the use of inelastic and short stretch compression therapy. In addition, several new compression devices and systems were introduced by industry representatives. This article summarizes the presentations and subsequent discussions and provides a description of the new compression therapies presented.

Acute oxygenation changes on ischemic foot of a novel intermittent pneumatic compression device and of an existing sequential device in severe peripheral arterial disease

Background

Intermittent pneumatic compression (IPC) improves haemodynamics in peripheral arterial disease (PAD), but its effects on foot perfusion were scarcely studied. In severe PAD patients we measured the foot oxygenation changes evoked by a novel intermittent IPC device (GP), haemodynamics and compliance to the treatment. Reference values were obtained by a sequential foot-calf device (SFC).

Methods

Twenty ischemic limbs (Ankle-Brachial Index = 0.5 ± 0.2) of 12 PAD patients (7 male, age: 74.5 ± 10.8 y) with an interval of 48 ± 2 hours received a 35 minute treatment in supine position with two IPC devices: i) a Gradient Pump (GP), which slowly inflates a single thigh special sleeve and ii) an SFC (ArtAssist^®, ACI Medical, San Marcos, CA, USA), which rapidly inflates two foot-calf sleeves. Main outcome measure: changes of oxygenated haemoglobin at foot (HbO_2foot) by continuous near-infrared spectroscopy recording and quantified as area-under-curve (AUC) for periods of 5 minutes. Other measures: haemodynamics by echo-colour Doppler (time average velocity (TAV) and blood flow (BF) in the popliteal artery and in the femoral vein), patient compliance by a properly developed form.

Results

All patients completed the treatment with GP, 9 with SFC. HbO_2foot during the working phase, considered as average value of the 5 minutes periods, increased with GP (AUC 458 ± 600 to 1216 ± 280) and decreased with SFC (AUC 231 ± 946 to −1088 ± 346), significantly for most periods (P < 0.05). The GP treatment was associated to significant haemodynamic changes from baseline to end of the treatment (TAV = 10.2 ± 3.3 to 13.5 ± 5.5 cm/sec, P = 0.004; BF = 452.0 ± 187.2 to 607.9 ± 237.8 ml/sec, P = 0.0001), not observed with SFC (TAV = 11.2 ± 3.4 to 11.8 ± 4.3 cm/sec; BF = 513.8 ± 203.7 to 505.9 ± 166.5 ml/min, P = n.s.). GP obtained a higher score of patient compliance (P < 0.0001).

Conclusions

A novel IPC thigh device, unlike a traditional SFC device, increased foot oxygenation in severe PAD, together with favourable haemodynamic response and high compliance to the treatment under the present experimental conditions.

Community walking programs for treatment of peripheral artery disease

BACKGROUND

Supervised walking programs offered at medical facilities for patients with peripheral artery disease (PAD) and intermittent claudication (IC), although effective, are often not used due to barriers, including lack of reimbursement and the need to travel to specialized locations for the training intervention. Walking programs for PAD patients that occur in community settings, such as those outside of supervised settings, may be a viable treatment option because they are convenient and potentially bypass the need for supervised walking. This review evaluated the various methods and outcomes of community walking programs for PAD.

METHODS

A literature review using appropriate search terms was conducted within PubMed/MEDLINE and the Cochrane databases to identify studies in the English language that used community walking programs to treat PAD patients with IC. Search results were reviewed, and relevant articles were identified that form the basis of this review. The primary outcome was peak walking performance on the treadmill.

RESULTS

Ten randomized controlled trials examining peak walking outcomes in 558 PAD patients demonstrated that supervised exercise programs were more effective than community walking studies that consisted of general recommendations for patients with IC to walk at home. Recent community trials that incorporated more advice and feedback for PAD patients in general resulted in similar outcomes, with no differences in peak walking time compared with supervised walking exercise groups.

CONCLUSIONS

Unstructured recommendations for patients with symptomatic PAD to exercise in the community are not efficacious. Community walking programs with more feedback and monitoring offer improvements in walking performance for patients with claudication and may bypass some obstacles associated with facility-based exercise programs.

Physiology in medicine: peripheral arterial disease

Peripheral arterial disease (PAD) is an atherosclerotic condition that can provoke symptoms of leg pain ("intermittent claudication") during exercise. Because PAD is often observed with comorbid conditions such hypertension, dyslipidemia, diabetes, cigarette smoking, and/or physical inactivity, the pathophysiology of PAD is certainly complex and involves multiple organ systems. Patients with PAD are at high risk for myocardial infarction, stroke, and all-cause mortality. For this reason, a better physiological understanding of the pathogenesis and treatment options for PAD patients is necessary and forms the basis of this Physiology in Medicine review.

Acute impact of intermittent pneumatic leg compression frequency on limb hemodynamics, vascular function, and skeletal muscle gene expression in humans

The mechanisms by which intermittent pneumatic leg compression (IPC) treatment effectively treats symptoms associated with peripheral artery disease remain speculative. With the aim of gaining mechanistic insight into IPC treatment, the purpose of this study was to investigate the effect of IPC frequency on limb hemodynamics, vascular function, and skeletal muscle gene expression. In this two study investigation, healthy male subjects underwent an hour of either high-frequency (HF; 2-s inflation/3-s deflation) or low-frequency (LF; 4-s inflation/16-s deflation) IPC treatment of the foot and calf. In study 1 (n = 11; 23.5 ± 4.7 yr), subjects underwent both HF and LF treatment on separate days. Doppler/ultrasonography was used to measure popliteal artery diameter and blood velocity at baseline and during IPC treatment. Flow-mediated dilation (FMD) and peak reactive hyperemia blood flow (RHBF) were determined before and after IPC treatment. In study 2 (n = 19; 22.0 ± 4.6 yr), skeletal muscle biopsies were taken from the lateral gastrocnemius of the treated and control limb at baseline and at 30- and 150-min posttreatment. Quantitative PCR was used to assess mRNA concentrations of genes associated with inflammation and vascular remodeling. No treatment effect on vascular function was observed. Cuff deflation resulted in increased blood flow (BF) and shear rate (SR) in both treatments at the onset of treatment compared with baseline (P < 0.01). BF and SR significantly diminished by 45 min of HF treatment only (P < 0.01). Both treatments reduced BF and SR and elevated oscillatory shear index compared with baseline (P < 0.01) during cuff inflation. IPC decreased the mRNA expression of cysteine-rich protein 61 from baseline and controls (P <0 .01) and connective tissue growth factor from baseline (P < 0.05) in a frequency-dependent manner. In conclusion, a single session of IPC acutely impacts limb hemodynamics and skeletal muscle gene expression in a frequency-dependent manner but does not impact vascular function.

Dynamic Ultrasound and Treadling: Novel Approaches to Assess and Improve Lower Extremity Circulation

The purpose of this study was to evaluate the safety and efficacy of a novel treatment of peripheral vascular disease through treadling and to report a dynamic vascular ultrasound technique. After informed consent, 17 volunteers were enrolled in the study. Ultrasound was used to measure venous and arterial waveforms at the superficial femoral artery and vein in the subject's right thigh during a 5-minute baseline evaluation (resting), a 10-minute treadling period, and a 5-minute cool down period. Comparisons between flow velocities were made during the three trial periods using a Repeated Measures Mixed Linear Model test with P < 0.05 considered significant. Twenty-six examinations were performed on subjects with an average age of 37 years (range, 25-75 years). Significant increases in maximum and minimum arterial and venous flow velocities during the treadling time compared with the resting and cool down period were observed ( P < 0.0001) with no change in the subjects’ vital signs. We found no significant difference in maximum and minimum arterial and venous flow velocities between the resting and cool down period ( P > 0.05). There were no untoward side effects, and all subjects were able to complete the protocol. Low-resistance treadling is safe and improves venous and arterial flow. Dynamic peripheral ultrasonography is a viable technique to assess flow during treadling. Potential future implications of this study include the evaluation, treatment, and management of lower extremity vascular and chronic diseases and more sensitive peripheral vascular sonography through dynamic ultrasound.

Prospective randomized controlled trial to analyze the effects of intermittent pneumatic compression on edema following autologous femoropopliteal bypass surgery

Background

Patients who undergo autologous femoropopliteal bypass surgery develop postoperative edema in the revascularized leg. The effects of intermittent pneumatic compression (IPC) to treat and to prevent postreconstructive edema were examined in this study.

Methods

In a prospective randomized trial, patients were assigned to one of two groups. All patients suffered from peripheral arterial disease, and all were subjected to autologous femoropopliteal bypass reconstruction. Patients in group 1 used a compression stocking (CS) above the knee exerting 18 mmHg (class I) on the leg postoperatively for 1 week (day and night). Patients in group 2 used IPC on the foot postoperatively at night for 1 week. The lower leg circumference was measured preoperatively and at five postoperative time points. A multivariate analysis was done using a mixed model analysis of variance.

Results

A total of 57 patients were analyzed (CS 28; IPC 29). Indications for operation were severe claudication (CS 13; IPC 13), rest pain (10/5), or tissue loss (7/11). Revascularization was performed with either a supragenicular (CS 13; IPC10) or an infragenicular (CS 15; IPC 19) autologous bypass. Leg circumference increased on day 1 (CS/IPC): 0.4%/2.7%, day 4 (2.1%/6.1%), day 7 (2.5%/7.9%), day 14 (4.7%/7.3%), and day 90 (1.0%/3.3%) from baseline (preoperative situation). On days 1, 4, and 7 there was a significant difference in leg circumference between the two treatment groups.

Conclusions

Edema following femoropopliteal bypass surgery occurs in all patients. For the prevention and treatment of that edema the use of a class I CS proved superior to treatment with IPC. The use of CS remains the recommended practice following femoropopliteal bypass surgery.

Intermittent pneumatic compression: physiologic and clinical basis to improve management of venous leg ulcers

Venous leg ulcers (VLUs) are a significant health problem that afflicts 1% of the population at some point during their lifetime. Intermittent pneumatic compression (IPC) is widely used to prevent deep venous thrombosis. However, IPC seems to have application to a broader base of circulatory diseases. The intermittent nature of pulsatile external compression produces beneficial physiologic changes, which include hematologic, hemodynamic, and endothelial effects, which should promote healing of VLUs. Clinical studies of the management of VLUs show that IPC increases overall healing and accelerates the rate of healing, leading to current guideline recommendations for care of patients with VLUs. Proper prescription of IPC to improve the management of patients with VLUs requires further definition. It seems that application of IPC in combination with sustained graduated compression improves outcome in patients with the most advanced venous disease.

Evaluation of A-V impulse technology as a treatment for oedema following polytetrafluoroethylene femoropopliteal surgery in a randomised controlled trial

OBJECTIVE

To investigate the efficacy of A-V impulse technology (A-V) for oedema prevention and treatment following PTFE femoropopliteal surgery.

DESIGN

Prospective randomized clinical trial.

MATERIALS

36 patients undergoing PTFE femoropopliteal bypass reconstructions, either being treated postoperatively with a compression stocking (CS) (Group-1, n = 19) or with A-V (Group-2, n = 17).

METHODS

Patients in treatment group-1 used a CS postoperatively during 1 week day and night, patients in group-2 were treated with A-V postoperatively at night during one week. The lower leg circumference was measured preoperatively and at five postoperative time points.

RESULTS

Limb circumference has increased postoperatively on day 1 (CS 1.5%/A-V 1.4%), on day 4 (5.7%/6.3%), on day 7 (6.6%/6.1%), on day 14 (7.9%/7.7%) and on day 90 (5.8%/5.2%). Differences between treatment groups were not significant. A re-operation gives a significant 3.9% increase in circumference as compared to a first operation (95% CI: 1.5-6.4%; p = 0.002).

CONCLUSION

No significant differences were found in the extent of developed edema between the groups following PTFE femoropopliteal bypass surgery. A redo peripheral bypass operation results in significantly more postoperative oedema than a first-time performed bypass operation.

A prospective randomized controlled study with intermittent mechanical compression of the calf in patients with claudication

OBJECTIVES

The study tested the feasibility of using a new portable mechanical compression device for the treatment of claudication. The device applies intermittent non-pneumatic mechanical compression (IMC) to the calf. It was hypothesized that it can offer a low-cost convenient option for patients and achieve good compliance and improved clinical outcomes.

METHODS

Thirty patients were enrolled in a randomized controlled single blind study. Fourteen patients were assigned to active IMC. Sixteen control patients continued with medical treatment alone. Outcomes were recorded at baseline, after one month, three months, and six months. The study examined changes in exercise tolerance using Initial Claudiacation Distance (ICD) and Absolute Claudiaction Distance (ACD) as well as ankle-brachial index at rest (ABI-r) and post-exercise (ABI-pe). All patients had stable claudication due to peripheral arterial disease (PAD) and were already under best medical treatment (BMT). To be eligible for inclusion, patients had to be between the ages of 50 and 75 years, had to have stable claudication with an absolute claudication distance >40 meters but <300 meters on a standardized treadmill stress test (3.8 km/h at a 10% grade), have a resting ABI in the affected limb <0.8 with a drop of at least 0.15 following exercise, in whom surgical intervention was not expected for at least three months. Fourteen patients were assigned to active IMC consisting of compressions 65 mm Hg in amplitude, applied for three 3-second compressions/minute, two hours/day for three months. Sixteen control patients continued with BMT alone.

RESULTS

One month after treatment, ICD increased by 66% (P = .001), ACD increased by 51.75% (P = .005), and ABI-pe increased by 42% (P = .01). Treatment effects were maintained or further improved after three months. ABI-r did not increase at any time. Compliance exceeded 80%. Three months following cessation of therapy, claudication distances and ABI-pe did not decrease significantly.

CONCLUSIONS

We concluded that the use of IMC of the calf for three months increased claudication distances and led to objective improvements in ABI-pe. Intermittent mechanical compression may be a useful approach to patients with continued claudication despite standard medical treatment.

Nonoperative active management of critical limb ischemia: initial experience using a sequential compression biomechanical device for limb salvage

Critical limb ischemia (CLI) patients are at high risk of primary amputation. Using a sequential compression biomechanical device (SCBD) represents a nonoperative option in threatened limbs. We aimed to determine the outcome of using SCBD in amputation-bound nonreconstructable CLI patients regarding limb salvage and 90-day mortality. Thirty-five patients with 39 critically ischemic limbs (rest pain = 12, tissue loss = 27) presented over 24 months. Thirty patients had nonreconstructable arterial outflow vessels, and five were inoperable owing to severe comorbidity scores. All were Rutherford classification 4 or 5 with multilevel disease. All underwent a 12-week treatment protocol and received the best medical treatment. The mean follow-up was 10 months (SD +/- 6 months). There were four amputations, with an 18-month cumulative limb salvage rate of 88% (standard error [SE] +/- 7.62%). Ninety-day mortality was zero. Mean toe pressures increased from 38.2 to 67 mm Hg (SD +/- 33.7, 95% confidence interval [CI] 55-79). Popliteal artery flow velocity increased from 45 to 47.9 cm/s (95% CI 35.9-59.7). Cumulative survival at 12 months was 81.2% (SE +/- 11.1) for SCBD, compared with 69.2% in the control group (SE +/- 12.8%) (p = .4, hazards ratio = 0.58, 95% CI 0.15-2.32). The mean total cost of primary amputation per patient is euro29,815 ($44,000) in comparison with euro13,900 ($20,515) for SCBD patients. SCBD enhances limb salvage and reduces length of hospital stay, nonoperatively, in patients with nonreconstructable vessels.

Prospective study to determine the effect of intermittent pneumatic foot and calf compression on popliteal artery peak systolic blood flow

OBJECTIVE

This study investigated the effects of posture and also intermittent foot and calf compression on peak systolic flow of the popliteal artery in a normal population.

METHODS

This was a prospective study carried out in normal subjects at the Vascular Laboratory, Department of Surgery, Hospital Kuala Lumpur, from March 2006 to September 2006. The study compared the popliteal artery blood flow during change of posture from the horizontal (supine) to the sitting position and the effect of intermittent pneumatic compression (IPC) of the foot and calf on popliteal artery blood flow immediately and 10 minutes after cessation of compression.

RESULTS

A total of 15 subjects involving 30 limbs were examined in this study. On comparing flows between the horizontal and sitting position, there was a mean reduction in blood flow of 23% (p < 0.005). Immediately after compression of the foot and calf, there was an increase in blood flow of between 4% and 35% with a mean of 15% (p < 0.05). Peak systolic flows at 10 minutes postcompression were 536 +/- 95 mL/min, which was still significantly higher than precompression measurements.

CONCLUSION

There is a significant reduction in popliteal artery blood flow on changing from the supine to the sitting position. Popliteal artery blood flow is higher than baseline after 15 minutes of intermittent pneumatic foot and calf compression. The increase in popliteal artery blood flow is still present 10 minutes after cessation of IPC.

Venous tonus enhancement after a short cycle of intermittent pneumatic compression

Objectives

To test if intermittent pneumatic compression (IPC) used with a short cycle could reproduce and confirm the 30 min vasoconstriction effect observed after a long cycle of pressure.

Methods

Eighteen subjects took part in the study, 12 with venous insufficiency (VI) and six without VI (NonVI). Duplex scanner was used to evaluate the diameter of six sites of veins on each of both lower limbs before and after the treatment. The IPC was applied to only one limb.

Results

The control limb showed no change in venous diameter. The treated limb, showed in the NonVI group one vasoconstriction: the greater saphena at the knee level (GS) ( P < 0.05). In the VI group, four sites out of six showed a vasoconstriction: the common femoral ( P < 0.005), the GS at its cross ( P < 0.001), the GS ( P < 0.001) and the lesser saphena ( P < 0.05).

Conclusions

Both long and short cycle of IPC are suitable to enhance the venous tone in VI patients for at least 30 min after the end of the treatment.

Long-term Intermittent Compression Increases Arteriographic Collaterals in a Rabbit Model of Femoral Artery Occlusion

OBJECTIVES

To assess the effects of intermittent limb compression on arterial collateral formation in a rabbit-model.

DESIGN

Animal study.

MATERIAL AND METHODS

New Zealand rabbits (n=11), aged 2-years, weight of at least 4.0 kg, underwent bilateral superficial femoral artery ligation. In ten of these, the experimental leg underwent 60 minutes of daily intermittent compression for a ten week period with 3 sec/90 mmHg pressure inflation and a cycle of 3 times per minute. The contra-lateral limbs were not treated. At the end of the ten-week period, high-resolution angiograms were obtained by barium infusion into the aorta. The angiograms were analyzed in a blinded manner and the number of collateral arteries larger than 100 microns, was counted. Following perfusion-fixation, histological specimens of transverse sections of the compressed semi-membranous muscle were examined.

RESULTS

The compressed limbs demonstrated a significantly (8.1+/-.87 vs 6.0+/-.97; p<0.005) greater number of collateral vessels, ranging in size from 100-700 microns, as compared to the control sides. The mean size of collaterals in the compressed limbs was not significantly different (0.33+/-0.17 vs 0.31+/-0.16). Microscopic examination of the collaterals confirmed remodeling by a typical neo-intima consisting of 6-7 cell-layers.

CONCLUSIONS

Intermittent limb compression increases the number of angiographical collateral arteries.

Unsupervised walking therapy and atherosclerotic risk-factor management for patients with peripheral arterial disease: a pilot trial

BACKGROUND

Although only a small percentage of patients with peripheral arterial disease (PAD) have claudication, many more suffer from atypical leg symptoms.

PURPOSE

This pilot trial evaluated a risk-factor modification program to improve walking ability in patients with PAD and leg symptoms other than intermittent claudication.

METHODS

Patients 18 years or older with an ankle-brachial index (ABI) of 0.50 to 0.89 completed a baseline assessment of current walking ability, physical activity level, health-related quality of life, glycosylated hemoglobin values, and fasting lipid profiles. Patients were randomized to usual care (control group) versus usual care plus an educational intervention on risk-factor management (intervention group). We compared functional outcomes between and within groups using the Student's t test and control and intervention group outcomes at 12 weeks using analysis of covariance with the baseline value as the covariate.

RESULTS

We randomized 50 patients into two treatment arms. There was no difference in the mean age of patients in each group. At baseline, mean ABI for the control versus the intervention group was 0.72 (SD = 0.10) and 0.75 (SD = 0.10), respectively, and mean stair-climbing values did not differ between groups. At 12 weeks, mean stair-climbing values were 40.2 (SD = 30.2) for the control and 61.2 (SD = 32.8) for the intervention group. The difference in adjusted mean walking distance between groups at 12 weeks was not significant. Analysis of covariance associated assignment to the intervention versus the control arm with a significant increase at 12 weeks in the ABI (p = .008) and stair-climbing ability (p = .02).

CONCLUSIONS

Patients in the intervention group improved objective measures of blood flow and reported stair-climbing ability.

Functional outcome of critical limb ischemia

Results of treatment for critical limb ischemia have traditionally focused on physician-oriented end points related to limb salvage surgery. Although numerous studies have demonstrated excellent patency and limb salvage after surgical revascularization procedures, survival in this patient population is poor, comorbidities reducing quality of life are rampant, and recovery from limb salvage surgery can be prolonged and complicated despite "success" as defined by traditional reporting methods. Patient-oriented outcome end points, such as health- related quality of life and functional status, are essential in defining optimal treatment options for the population of patients with critical limb ischemia. This area of research remains in its infancy, but will become increasingly important as the population of patients with critical limb ischemia and treatment options for these patients continue to expand. The current status and future outlook of functional and quality of life assessment of patients with critical limb ischemia is reviewed.

Successful iliac vein and inferior vena cava stenting ameliorates venous claudication and improves venous outflow, calf muscle pump function, and clinical status in post-thrombotic syndrome

OBJECTIVES

Stent therapy has been proposed as an effective treatment of chronic iliofemoral (I-F) and inferior vena cava (IVC) thrombosis. The purpose of this study was to determine the effects of technically successful stenting in consecutive patients with advanced CVD (CEAP3-6 +/- venous claudication) for chronic obliteration of the I-F (+/-IVC) trunks, on the venous hemodynamics of the limb, the walking capacity, and the clinical status of CVD. These patients had previously failed to improve with conservative treatment entailing compression and/or wound care for at least 12 months.

METHODS

The presence of venous claudication was assessed by > or =3 independent examiners. The CEAP clinical classification was used to determine the severity of CVD. Outflow obstruction [Outflow Fraction at 1- and 4-second (OF1 and OF4) in %], venous reflux [Venous Filling Index (VFI) in mL/100 mL/s], calf muscle pump function [Ejection Fraction (EF) in %] and hypertension [Residual Venous Fraction (RVF) in %], were examined before and after successful venous stenting in 16 patients (23 limbs), 6 females, 10 males, median age 42 years; range, 31-77 yearas, left/right limbs 14/9, using strain gauge plethysmography; 7/16 of these had thrombosis extending to the IVC. Contralateral limbs to those stented without prior I-F +/- IVC thrombosis, nor infrainguinal clots on duplex, were used as control limbs (n = 9). Excluded were patients with stent occlusion or stenoses, peripheral arterial disease (ABI <1.0), symptomatic cardiac disease, unrelated causes of walking impairment, and malignancy. Preinterventional data (< or =30 days) were compared with those after endovascular therapy (8.4 months; interquartile range [IQR], 3-11.8 months). Nonparametric analysis was applied.

RESULTS

Compared with the control group, limbs with I-F +/- IVC thrombosis before stenting had reduced venous outflow (OF4) and calf muscle pump function (EF), worse CEAP clinical class, and increased RVF (all, P < 0.05). At 8.4 months (IQR, 3-11.8 months) after successful I-F (+/-IVC) stenting, venous outflow (OF1, OF4) and calf muscle pump function (EF) had both improved (P < 0.001) and the RVF had decreased (P < 0.001), at the expense of venous reflux, which had increased further (increase of median VFI by 24%; P = 0.002); the CEAP status had also improved (P < 0.05) from a median class C3 (range, C3-C6; IQR, C3-C5) [distribution, C6: 6; C4: 4; C3: 13] before intervention to C2 (range, C2-C6; IQR, C2-C4.5) [distribution, C6: 1; C5: 5; C4: 4; C2: 13] after intervention. At this follow up (8.4 months median), venous outflow (OF1, OF4), calf muscle pump function (EF), and RVF of the stented limbs did not differ significantly from those of the control; significantly worse (P < 0.025) were the amount of venous reflux (VFI), and the CEAP clinical class, despite the improvement with stenting. Incapacitating venous claudication noted in 62.5% (10 of 16, 95% CI, 35.8%-89.1%) of patients (15 of 23 limbs; 65.2%, 95% CI, 44.2%-86.3%) before stenting was eliminated in all after stenting (P < 0.001).

CONCLUSIONS

Successful I-F (+/-IVC) stenting in limbs with venous outflow obstruction and complicated CVD (C3-C6) ameliorates venous claudication, normalizes outflow, and enhances calf muscle pump function, compounded by a significant clinical improvement of CVD. The significant increase in the amount of venous reflux of the stented limbs indicates that elastic or inelastic compression support of the successfully stented limbs would be pivotal in preventing disease progression.

Hemodynamic impairment, venous segmental disease, and clinical severity scoring in limbs with Klippel-Trenaunay syndrome

BACKGROUND

Klippel-Trenaunay syndrome (KTS) is a complex congenital anomaly featuring two or more of the following: (1) capillary malformations (port-wine stains), (2) soft tissue or bony hypertrophy (or both), and (3) varicose veins or venous malformations. With the purpose of determining the actual significance of venous impairment in patients with KTS, we quantified the venous valvular competency and calf muscle pump function and examined their effect on clinical severity.

METHODS

Included were patients with near-normal function of affected limb(s) and minimal/small foot hypertrophy. Excluded were those with deep venous hypoplasia, aplasia or thrombosis, lymphedema, limb length discrepancy (>2.5 cm), peripheral arterial (ankle-brachial index <1.0), or cardiac disease and walking impairment. Venous duplex scanning, ascending venography, magnetic resonance imaging, strain gauge plethysmography, and a bone scanogram were performed. We studied eight men and seven women aged 15 to 51 years (median, 24 years). The KTS involved 17 limbs (unilateral in 13 patients and bilateral in 2). Contralateral limbs in patients with unilateral KTS acted as controls (n = 13). Venous clinical severity was graded according to the CEAP and venous clinical severity score (VCSS), and reflux complexity was classified according to the venous segmental disease score. Outflow obstruction (outflow fraction at 1 and 4 seconds; OF(1) and OF(4), respectively), reflux (venous filling index), calf muscle pump function (ejection fraction), and hypertension (residual volume fraction) were determined in both limbs with strain gauge plethysmography. Data, reported as median and interquartile range, were analyzed with the Mann-Whitney test.

RESULTS

Varicose veins or venous malformations occurred in the medial, posterior, or anterolateral limb segments of the ankle (7/17, 7/17, and 9/17), calf (10/17, 8/17, and 12/17), knee (9/17, 8/17, and 8/17), and thigh (10/17, 6/17, and 8/17, respectively). Venous malformations occupied the subcutaneous space (17/17) and extended into the subfascial space in 6 (35.3%) of 17 limbs. Abnormal reflux (>0.5 seconds) was distributed in the great (64.7%; 11/17) and small (5.9%; 1/17) saphenous veins and the common femoral (23.5%; 4/17), femoral (41.1%; 7/17), popliteal (29.4%; 5/17), perforator (70.6%; 12/17), and axial calf (35.3%; 6/17) veins. There was no difference in the OF(1) and OF(4) between the affected limbs and the controls. Limbs with KTS had a fivefold greater venous filling index (0.133-0.46 mL . 100 mL(-1) . s(-1); 0.258 mL . 100 mL(-1) . s(-1)) than the controls (0.034-0.055 mL . 100 mL(-1) . s(-1); 0.046 mL . 100 mL(-1) . s(-1); P < .0001), and this was linked to a higher venous segmental disease score (3 [2-4] vs 0 [0-1]; P < .0001). Limbs with KTS had half the ejection fraction (20.8%; 12.3%-24%) of the controls (39.3%; 30.9%-64.6%) and twice as high a residual venous fraction (77% [69.6%-84.5%] vs 40.9% [20.6%-60%]; both P < .004). Patients complained of swelling (100%; 15/15), aching (100%; 15/15), pain (93.3%; 14/15) and heaviness (100%; 15/15), tiredness (66.7%; 10/15), and tightness (33.3%; 5/15) of the limb(s) with KTS. Limbs with KTS had a worse (1) venous clinical severity by 11 VCSS points (11 [8-12] vs 0 [0-1]) and (2) clinical status by 3 CEAP classes (C3 [C3-C4] vs C0 [C0-C2]) than the control limbs (both P < .0001).

CONCLUSIONS

Venous disease in limbs with KTS is a major source of morbidity in affected patients. Limbs with KTS are characterized by complex reflux patterns, severe valvular incompetence, calf muscle pump impairment, and venous hypertension, thus explaining the advanced clinical severity (VCSS) and CEAP grade.

Haemodynamic and Clinical Impact of Superficial, Deep and Perforator Vein Incompetence

OBJECTIVE

The purpose of this study was to assess the effect of venous incompetence of the deep, superficial and perforator veins combined (i.e. multi-system incompetence) on the venous haemodynamics and clinical condition of limbs with chronic venous disease (CVD).

METHODS

One hundred and thirty two limbs (16-C(1); 30-C(2); 20-C(3); 25-C(4); 21-C(5); 20-C(6)) of 121 patients were studied. We excluded those with previous venous surgery/sclerotherapy, peripheral arterial disease, recent deep vein thrombosis (< or =6 months), or inability to comply with the tests. The CEAP clinical class was assessed. Duplex ultrasonography (ultrasound) enabled classification according to: the presence of superficial([S]) (+/- perforator([P])) or deep([D]) (+/-S, +/-P) reflux (>.5s); the number of incompetent venous systems (single-system([S/P/D]), dual-system([S+P/S+D/P+D]), or triple-system([S+P+D])), and the number of incompetent perforators([0/1/2/> or =3]). The amount of reflux (Venous Filling Index([VFI])); calf pump Ejection Fraction([EF]), and Residual Volume Fraction([RVF]) were studied with air-plethysmography.

RESULTS

VFI in limbs with triple-system incompetence (VFI median 6.68 [IQR: 4.7-9.7]ml/s) was higher than in limbs with dual-system incompetence (4.5 [2.1-7.4]ml/s), and VFI in the latter was higher than in limbs with single-system incompetence (1.3 [0.69-2.3]ml/s)(p<0.01 Kruskal-Wallis). Although EF changes were small, RVF in limbs with triple-incompetence (39 [30-51] %) was higher than in single-system incompetence (26 [16-33] %)(p<0.01 Mann-Whitney). Limbs with superficial (+/-P) incompetence had a lower VFI (p<0.01) and RVF (p<0.02) than limbs with deep (+/-S+/-P) incompetence, and limbs with > or =2 incompetent perforator veins had a higher VFI (p<0.04) than those without perforators. All limbs with single-system incompetence were C(1-3,) whereas 78% of those with triple-incompetence were C(4-6) (p<0.01). The number of incompetent systems increased with clinical class (p<0.01).

CONCLUSIONS

The frequency of incompetence of more than one venous system increased with the clinical severity of venous disease and was accompanied by a 5-fold increase in the amount of reflux and a 50% rise in the RVF. The number of incompetent perforators per limb increased with the amount of reflux. The number of incompetent venous systems (superficial, deep, perforator) and perforator veins can be assessed by duplex ultrasound giving an objective indication of the functional severity of venous disease. In this way duplex ultrasound could be used to grade venous function in clinical practice as an alternative to APG measures which are less widely available.

Measurement, calculation, and normal range of the ankle-arm index: a bibliometric analysis and recommendation for standardization

Since its introduction in 1950, a variety of methods of measurement and calculation have been used to establish the ankle-arm index (AAI). This has resulted in variations of its normal range and difficulty in comparing study results. Hence, the objective of our study was to analyze the disparate methods used to assess AAI and its normal range and to recommend a standardized method to assess AAI based on that analysis. We made an inventory of the disparate AAI methods and its normal range reported in 100 randomly selected publications and recommend the means of such standardization. We recommend that an experienced observer assess AAI with the patient at rest in the supine position. The width of the sphygmometer cuffs should be 1.5 times that of the extremity to be measured, and brachial and crural pulses should be detected using a Doppler device. Systolic pressures should be measured at both arms and over the anterior and posterior arteries of both legs, with the cuff placed just proximally to the malleoli. The left arm pressure ought to be used as denominator and the mean of pressures of both crural arteries of each leg ought to be used for the numerator of the AAI for that leg. We advocate 0.90 as the cut-off value to distinguish patients who need further arterial assessment.

Duration and amplitude decay of acute arterial leg inflow enhancement with intermittent pneumatic leg compression: An insight into the implicated physiologic mechanisms

PURPOSE

By acutely enhancing the arterial leg inflow, intermittent pneumatic leg compression (IPC) improves the walking ability, arterial hemodynamics, and quality of life of claudicants. We quantified the duration of acute leg inflow enhancement with IPC of the foot (IPC(foot)), calf (IPC(calf)), or both (IPC(foot+calf)) and its amplitude decay in claudicants and controls in relation to the pulsatility index, an estimate of peripheral resistance. These findings are cross-correlated with the features of the three implicated physiologic mechanisms: (1) an increase in the arteriovenous pressure gradient, (2) suspension of peripheral sympathetic autoregulation, and (3) enhanced release of nitric oxide with flow and shear-stress increase.

METHODS

Twenty-six limbs of 24 claudicants with superficial femoral artery occlusion or stenoses (>75%) and 24 limbs of 20 healthy controls matched for age and sex, meeting stringent selection criteria, had their popliteal volume flow and pulsating index (peak-to-peak velocity/mean velocity) measured with duplex scanning at rest and upon delivery of IPC. Spectral waveforms were analyzed for 50 seconds after IPC delivery per 5-second segments. The three IPC modes were applied in a true crossover design. Data analysis was performed with the Page, Friedman, Wilcoxon, Mann-Whitney and chi2 tests.

RESULTS

The median duration of flow enhancement in claudicants exceeded 50 seconds with IPC(foot), IPC(calf), and IPC(foot+calf) but was shorter (P < .001) in the controls (32.5 to 40 seconds). Among the three IPC modes, the duration of flow enhancement differed (P < .05) only between IPC(foot) and IPC(foot+calf). After reaching its peak within 5 seconds of IPC, flow enhancement decayed at rates decreasing over time (trend, P < .05, Page test), which in both groups were highest at 5 to 20 seconds, moderate at 20 to 35 seconds, and lowest at 35 to 50 seconds (P < .05, Friedman test). Baseline and peak flow with all IPC modes was similar between the two groups. Pulsatility index attenuation in claudicating limbs lasted a median 32.5 seconds with IPC(foot), 37.5 seconds with IPC(calf), and 40 seconds with IPC(foot+calf); duration of pulsatility index attenuation was shorter in the control limbs with IPC(foot) (30 seconds), IPC(calf) (32.5 seconds), or IPC(foot+calf) (35 seconds), yet differences, as well as those among the 3 IPC modes, were not significant.

CONCLUSION

Leg inflow enhancement with IPC exceeds 50 seconds in claudicants and lasts 32.5 to 40 seconds in the controls. Peak flow occurs concurrently with maximal pulsatility index attenuation, within 5 seconds of IPC. Irrespective of group or IPC mode, the decay rate (%) of flow enhancement is highest within 5 to 20 seconds of IPC, moderate at 20 to 35 seconds, and lowest at 35 to 50 seconds. Since attenuation in peripheral resistance terminates with the mid time period (20 to 35 seconds) of flow decay, and nitric oxide has a half-life of <7 to 10 seconds, the study's data indicate that all implicated physiologic mechanisms (1, 2, and 3) are likely active immediately after IPC delivery (0 to 20 sec) and all but nitric oxide are effective in the mid time period (20 to 35 seconds). As the pulsatility index has returned to baseline, the late phase of flow enhancement (35 to 50 seconds) could be attributable to the declining arteriovenous pressure gradient alone.

Hemodynamic effects of intermittent pneumatic compression in patients with critical limb ischemia

BACKGROUND

Traditional teaching assumes that the distal arterial tree is maximally dilated in patients with critical limb ischemia (CLI). Endovascular or arterial bypass procedures are the commonly used interventions to increase distal perfusion. However, other forms of treatment such as spinal cord stimulation or intermittent pneumatic compression (IPC) have been shown to improve limb salvage rates. This prospective study was designed to determine if the use of IPC increases popliteal, gastrocnemial, collateral arterial, and skin blood flow in patients with CLI.

METHODS

Twenty limbs with CLI in 20 patients (mean age, 74 years) were evaluated with duplex ultrasound scans and laser Doppler fluxmetry in the semi-erect position before, during, and after IPC. One pneumatic cuff was applied on the foot and the other on the calf. The maximum inflation pressure was 120 mm Hg and was applied for 3 seconds at three cycles per minute. All patients had at least two-level disease by arteriography. Fourteen limbs were characterized as inoperable, and six were considered marginal for reconstruction. Flow volumes were measured in the popliteal, medial gastrocnemial, and a genicular collateral artery. Skin blood flux was measured on the dorsum of the foot at the same time.

RESULTS

Significant flow increase during the application of IPC was found in all three arteries (18/20 limbs) compared with baseline values (P < .02). The highest change was seen in the popliteal, followed by the gastrocnemial and the collateral artery. After the cessation of IPC, the flow returned to baseline. This was attributed to the elevation of time average velocity, as the diameter of the arteries remained unchanged. The skin blood flux increased significantly as well (P < .03). In the two limbs without an increase in the arterial or skin blood flow, significant popliteal vein reflux was found. Both limbs were amputated shortly after.

CONCLUSIONS

IPC increases axial, muscular, collateral, and skin blood flow in patients with CLI and may be beneficial to those who are not candidates for revascularization. Patients with significant venous reflux may not benefit from IPC. This supports the theory that one of the mechanisms by which IPC enhances flow is by increasing the arteriovenous pressure gradient.

Improvement of the Walking Ability in Intermittent Claudication due to Superficial Femoral Artery Occlusion with Supervised Exercise and Pneumatic Foot and Calf Compression: A Randomised Controlled Trial

OBJECTIVES

To compare the effect of unsupervised exercise, supervised exercise and intermittent pneumatic foot and calf compression (IPC) on the claudication distance, lower limb arterial haemodynamics and quality of life of patients with intermittent claudication.

METHODS

Thirty-four eligible patients with stable intermittent claudication were randomised to IPC (n = 13, 3h/d for 6 months), supervised exercise (n = 12, three hourly sessions/week for 6 months) or unsupervised exercise (n = 9). In each patient, initial claudication distance (ICD), absolute claudication distance (ACD), resting ankle brachial pressure index (ABPI), and resting hyperaemic calf arterial inflow were measured before, 6 weeks, 6 months and 1 year after randomisation. Quality of life was assessed with the short form (SF)-36, walking impairment (WIQ) and intermittent claudication questionnaires (ICQ).

RESULTS

Compared with unsupervised exercise, both IPC and supervised exercise, increased ICD and ACD, up to 2.83 times. IPC increased arterial inflow (p < 0.05 at 6 weeks) and ABPI. Supervised exercise decreased arterial inflow and increased ABPI (p < 0.05 at 6 months). Unsupervised exercise had no effect on arterial inflow or ABPI. IPC improved significantly the ICQ score and the speed score of the WIQ, while supervised exercise improved the WIQ claudication severity score. At 1 year clinical effectiveness of supervised exercise and IPC was largely preserved.

CONCLUSIONS

IPC, by augmenting leg perfusion, achieved improvement in walking distance comparable with supervised exercise. Long-term results in a larger number of patients will provide valuable information on the optimal treatment modality of intermittent claudication.

The effect of intermittent pneumatic compression on the bone uptake of (99m)Tc-labelled methylene diphosphonate in the lower limb

INTRODUCTION

Venous compression of the lower limbs will obstruct outflow through the deep and superficial veins, yet inflow will continue, without continual swelling of the limb. It is hypothesised that venous channels in the long bones act as collateral channels to restore outflow, and therefore general blood flow through bone will increase. Such a hemodynamic change should affect the uptake of radiopharmaceuticals by the bone, though uptake changes in themselves would not definitely indicate flow changes. The purpose of this study, therefore, was to determine whether bone uptake in the lower limb is affected by intermittent venous compression, irrespective of the mechanism involved.

MATERIALS AND METHODS

The effect of intermittent pneumatic compression of the thigh and calf on the uptake of (99m)Tc-methylene diphosphonate (MDP) was studied in 24 patients. All were undergoing routine bone imaging for medical conditions that were not focused on their lower limbs, and received 1 h of the therapy at 60 mmHg on one limb only, after injection of the radiopharmaceutical. Three hours after injection the relative difference in uptake (net counts per pixel) between the two limbs was calculated. The standard imaging protocol was otherwise unchanged.

RESULTS

The median differences in uptake in the intermittently compressed limb compared with the contralateral limb were +7.6% (interquartile range +3.9% to +16.0%, p<0.0005 [Wilcoxon]) for the anterior aspect of the femur; +11.7% (interquartile range +4.3% to +22.2%, p<0.0005) posterior, femur; +10.5% (interquartile range +6.5% to +13.8%, p<0.0005) anterior, tibia; +10.6% (interquartile range +5.5% to +17.6%, p<0.0005) posterior, tibia.

CONCLUSION

Intermittent pneumatic compression clearly and significantly increased the uptake of (99m)Tc-MDP in long bones. These data are consistent with increases in blood flow through bone, though a direct mechanical influence on the bone cannot be excluded. This effect should be given consideration during routine therapeutic and thromboprophylactic use of intermittent compression, and if the mechanism of the uptake changes can be established, their possible clinical uses should be investigated.

Rapid foot and calf compression increases walking distance in patients with intermittent claudication: results of a randomized study

OBJECTIVE

The aim of our pilot study was to determine the usefulness of rapid, high-pressure, intermittent pneumatic calf and foot compression (IPCFC) in patients with stable intermittent claudication, with reference to the end points of improvement in initial claudication distance (ICD) (distance at which patient feels pain or discomfort in the legs), and improvement in absolute claudication distance (ACD) (distance at which patient stops walking because the pain or discomfort becomes severe).

METHODS

Thirty male patients presenting with stable, intermittent claudication (ACD between 50 and 150 meters on treadmill testing at 3.8 km/h, 10 degrees gradient) were recruited into this pilot study from a single center. Fifteen patients were randomized to treatment with IPCFC (applied for 1 hour twice daily in the sitting position) and were also advised to have daily exercise, and 15 patients served as controls, who were advised exercise alone. All patients received aspirin and had resting and postexercise ankle/brachial index (ABI) measured at enrollment along with ICD and ACD on treadmill testing (3.8 km/h, 10 degrees gradient). The mean age, baseline ICD, and ACD of the treatment and control groups were 70.4 +/- 7 years and 70.7 +/- 9 years, 55.8 +/- 15 meters and 68.4 +/- 17 meters, and 86.7 +/- 19 meters and 103.9 +/- 27 meters, respectively. Both groups were equally matched for risk factors, including smoking, type II diabetes mellitus, and hypercholesterolemia. IPCFC was applied. The study protocol included follow-up visits at 1, 2, 3, 4, 6, and 12 months with the ABI, ICD and ACD being measured at every visit.

RESULTS

The percent change from baseline for ICD and ACD for each patient visit and the mean +/- standard deviation (SD), standard error (SE), and median were calculated for the control and treatment groups. The percent change from baseline measurements (mean +/- SD) for ICD and ACD in the control group at 4, 6, and 12 months were 2.2 +/- 18 and 2.3 +/- 18, 2.9 +/- 17 and 5.2 +/- 20, and 3.6 +/- 18 and 5.8 +/- 20, respectively. In contrast, the changes in ICD and ACD at 4, 6, and 12 months in the treatment group were 137.1 +/- 128 (P < .01) and 84.3 +/- 82 (P < .01), 140.6 +/- 127 (P < .01) and 96.4 +/- 106 (P = .01), and 150.8 +/- 124 (P <0.01) and 101.2 +/- 104 (P <0.01), respectively. Although the ABI showed a slight increase in the treatment group, these differences were not statistically significant.

CONCLUSIONS

The results of this pilot study show that IPCFC improves walking distance in patients with stable intermittent claudication. A significant increase in ICD and ACD was seen at 4 and 6 months of treatment, respectively, and the improvement was sustained at 1 year. The combination of IPCFC with other treatment such as risk-factor modification and daily exercise may prove useful in patients with peripheral arterial occlusive disease. It may be a useful first line of therapy in patients with disabling claudication who are unfit for major reconstructive surgery. Improved walking on long-term follow-up and experience from different centers may establish a role for this treatment modality in the future.

Effect of intermittent pneumatic compression of foot and calf on walking distance, hemodynamics, and quality of life in patients with arterial claudication: a prospective randomized controlled study with 1-year follow-up

SUMMARY BACKGROUND DATA

Perioperative mortality, graft failure, and angioplasty limitations militate against active intervention for claudication. With the exception of exercise programs, conservative treatments yield modest results. Intermittent pneumatic compression [IPC] of the foot used daily for 3 months enhances the walking ability and pressure indices of claudicants. Although IPC applied to the foot and calf together [IPCfoot+calf] is hemodynamically superior to IPC of the foot, its clinical effects in claudicants remain undetermined.

OBJECTIVE

This prospective randomized controlled study evaluates the effects of IPCfoot+calf on the walking ability, peripheral hemodynamics, and quality of life [QOL] in patients with arterial claudication.

METHODS

Forty-one stable claudicants, meeting stringent inclusion and exclusion criteria, were randomized to receive either IPCfoot+calf and aspirin[75 mg] (Group 1; n = 20), or aspirin[75 mg] alone (Group 2; n = 21), with stratification for diabetes and smoking. Groups matched for age, sex, initial [ICD] and absolute [ACD] claudication distances, pressure indices [ABI], popliteal artery flow, and QOL with the short-form 36 Health Survey Questionnaire (SF-36). IPCfoot+calf (120 mm Hg, inflation 4 seconds x 3 impulses per minute, calf inflate delay 1 second) was used for 5 months, > or =2.5 hours daily. Both groups were advised to exercise unsupervised. Evaluation of patients, after randomization, included the ICD and ACD, ABI, popliteal artery flow with duplex and QOL* at baseline*, 1/12, 2/12, 3/12, 4/12, 5/12* and 17/12. Logbooks allowed compliance control. Wilcoxon and Mann-Whitney corrected[Bonferroni] tests were used.

RESULTS

At 5/12 median ICD, ACD, resting and postexercise ABI had increased by 197%, 212%, 17%, and 64%, respectively, in Group 1 (P < 0.001), but had changed little (P > 0.1) in Group 2; Group 1 had better ICD, ACD, and resting and postexercise ABI (P < 0.01) than Group 2. Inter- and intragroup popliteal flow differences at 5/12 were small (P > 0.1). QOL had improved significantly in Group 1 but not in Group 2; QOL in the former was better (P < 0.01) than in Group 2. QOL in Group 1 was better (P < 0.01) than in Group 2 at 5/12. IPC was complication free. IPC compliance (> or =2.5 hours/d) was >82% at 1 month and >85% at 3 and 5 months. ABI and walking benefits in Group 1 were maintained a year after cessation of IPC treatment.

CONCLUSIONS

IPCfoot+calf emerged as an effective, high-compliance, complication-free method for improving the walking ability and pressure indices in stable claudication, with a durable outcome. These changes were associated with a significant improvement in all aspects of QOL evaluated with the SF-36. Despite some limited benefit noted in some individuals, unsupervised exercise had a nonsignificant impact overall.