Initial Claudication Distance Research Articles

Metabolic syndrome impairs physical function, health-related quality of life, and peripheral circulation in patients with intermittent claudication

This study was conducted to (1) examine the effect of metabolic syndrome on intermittent claudication, physical function, health-related quality of life, and peripheral circulation in patients with peripheral arterial disease (PAD), and (2) determine whether peripheral vascular function was predictive of intermittent claudication and physical function in patients with metabolic syndrome. Patients limited by intermittent claudication and who had metabolic syndrome (n = 133) were compared with those without metabolic syndrome (n = 201). Patients were assessed on metabolic syndrome characteristics, PAD-specific measures consisting of ankle/brachial index and claudication distances, physical function measures, health-related quality of life, and calf blood flow and transcutaneous oxygen tension responses after 3 minutes of vascular occlusion. Initial claudication distance (mean +/- SD) was 29% shorter (P = .018) in patients with metabolic syndrome than in the controls (128 +/- 121 meters vs 180 +/- 166 meters), and absolute claudication distance was 22% shorter (P = .025) in those with metabolic syndrome (319 +/- 195 meters vs 409 +/- 255 meters). Furthermore, patients with metabolic syndrome had lower peak oxygen uptake (P = .037), a shorter 6-minute walk distance (P = .027), lower values on six domains of health-related quality of life (P < .05), reduced calf hyperemia (P = .028), and greater calf ischemia (P < .001) after vascular occlusion. In the group with metabolic syndrome, calf ischemia was correlated with initial claudication distance (r = 0.30, P = .004), absolute claudication distance (r = 0.40, P < .001), and peak oxygen uptake (r = 0.52, P < .001). Metabolic syndrome worsens intermittent claudication, physical function, health-related quality of life, and peripheral circulation in patients with PAD. Calf ischemia in those with metabolic syndrome was predictive of intermittent claudication and physical function. The additive burden of metabolic syndrome thus places patients who are limited by intermittent claudication at an even greater risk for living a functionally dependent lifestyle. Aggressive risk-factor modification designed to treat components of metabolic syndrome should be evaluated for efficacy in modifying physical and vascular function in patients with intermittent claudication.

The PADHOC Device is a Better Guide to the Actual Incapacity Suffered by Claudicants than the Gold Standard Constant Load Treadmill Test

The Constant Load Treadmill Test (CLTT) is currently the primary method used to measure walking impairment in patients with peripheral vascular disease. The aim of this study was to compare the CLTT and PADHOC device as assessments of walking impairment. 55 patients with intermittent claudication underwent a CLTT and a Double Physiological Walking Test (DPWT) using the PADHOC device. Health-related quality of life was measured using the Short Form 36 and the Claudication Scale. The initial claudication and maximum walking distance from the first part of the DPWT showed the best correlation with domains of pain and physical function. The DPWT is more representative of the functional incapacity experienced by patients with intermittent claudication. We believe that the PADHOC is a suitable alternative to the CLTT in the assessment of this patient group.

Metabolic Syndrome Impairs Function, Health-Related Quality of Life, and Peripheral Circulation in Patients with Intermittent Claudication

Patients limited by intermittent claudication have multiple co-morbid conditions and are sendentary, thereby increasing their risk of having metabolic syndrome. Metabolic syndrome's possible negative effects on ambulation and peripheral circulation in these patients are of particular importance. PURPOSE: To examine the effect of metabolic syndrome on intermittent claudication and peripheral circulation in patients with peripheral arterial disease (PAD), and to determine whether peripheral vascular function was predictive of the severity of intermittent claudication in patients with metabolic syndrome. METHODS: Patients limited by intermittent claudication who had metabolic syndrome (n = 155) were compared to those without metabolic syndrome (n = 428). Patients were assessed on metabolic syndrome characteristics, ambulatory function, and peripheral vascular function. RESULTS: Initial claudication distance (ICD) was 30% shorter (p = 0.007) in patients with metabolic syndrome than in the controls (133 ± 119 vs. 189 ± 165 m; mean ± SD), and absolute claudication distance (ACD) was 21% shorter (p = 0.028) (327 ± 194 vs. 413 ± 248 m). Furthermore, patients with metabolic syndrome had greater calf ischemia (p = 0.016) following a vascular occlusion test. Calf ischemia was correlated with ICD (r = 0.28, p = 0.031), and ACD (r = 0.39, p = 0.003) in the group with metabolic syndrome. CONCLUSION: Metabolic syndrome worsens intermittent claudication and peripheral circulation in patients with PAD. Thus, the additive burden of metabolic syndrome places patients limited by intermittent claudication at even greater risk for living a functionally dependent lifestyle. Supported by NIH (R01-AG-16685, K01-00657).

Inflammation and Chlamydia pneumoniae Infection Correlate with the Severity of Peripheral Arterial Disease

Background Our aim was to investigate the association of inflammation and Chlamydia pneumoniae infection with the presence and severity of peripheral arterial disease. Methods Twenty-eight patients whose initial claudication distance (ICD) in the traditional constant-load treadmill test was <200 m, underwent femoral endarterectomy as part of their interventional treatment (group A). Group B consisted of 23 patients whose ICD was >200 m and were put on medication and a daily exercise program. The control group consisted of 30 non-vascular patients of the Ophthalmology Department (group C). We measured the levels of C-reactive protein, fibrinogen, vascular cell adhesion molecule-1 and tumor necrosis factor-α, and the titers of IgA and IgG antibodies against C. pneumoniae in the serum of all the patients. Finally, the atheromas and vein segments of group A patients, were immunohistochemically (IHC) examined for the presence of C. pneumoniae. Results Peripheral arterial disease (PAD) patients, had significantly higher CRP (p=0.026) and anti-Cp IgA levels (p=0.001) when compared to control subjects, after a multiple linear regression analysis. The odds ratio for the prevalence of femoral atherosclerosis was 3.16 for IgA seropositive patients (CI 1.15–8.67). When comparing group A and group B patients, CRP (p=0.003) and IgA (p=0.011), were significantly correlated with severe PAD. Group A patients with positive immunohistochemical examination of the plaque, had higher anti-Cp IgA levels (p=0.023) and TNF-α values (p=0.031), compared to the IHC negative patients. C. pneumoniae was detected in 50% of the femoral atheromas, but in only 3.6% of the veins. Conclusion This study supports the hypothesis that inflammation (CRP) and chronic C. pneumoniae infection (IgA seropositivity), have an important role in lower limb atherosclerosis and correlate with the severity of the disease.

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

The authors evaluated the effect of intermittent pneumatic compression on the walking ability, peripheral hemodynamics and quality of life in patients with claudication. Forty-one patients with claudication were randomized to intermittent compression and aspirin or aspirin alone. Inflation for 4 seconds at 3 impulses per minute, calf inflate delay 2 second was used for 5 months for at least 2.5 hours daily. The claudication patients who had intermittent pneumatic compression had improved initial and absolute claudication distance on treadmill testing and improved ankle-brachial index measurements compared with those who did not. The authors concluded that intermittent pneumatic compression was effective method for improving walking ability and pressure indices.

The effect of exercise intensity on the response to exercise rehabilitation in patients with intermittent claudication

The purpose of this randomized trial was to compare the efficacy of a low-intensity exercise rehabilitation program vs a high-intensity program in changing physical function, peripheral circulation, and health-related quality of life in peripheral arterial disease (PAD) patients limited by intermittent claudication. Thirty-one patients randomized to low-intensity exercise rehabilitation and 33 patients randomized to high-intensity exercise rehabilitation completed the study. The 6-month exercise rehabilitation programs consisted of intermittent treadmill walking to near maximal claudication pain 3 days per week at either 40% (low-intensity group) or 80% (high-intensity group) of maximal exercise capacity. Total work performed in the two training regimens was similar by having the patients in the low-intensity group exercise for a longer duration than patients in the high-intensity group. Measurements of physical function, peripheral circulation, and health-related quality of life were obtained on each patient before and after the rehabilitation programs. After the exercise rehabilitation programs, patients in the two groups had similar improvements in these measures. Initial claudication distance increased by 109% in the low-intensity group (P < .01) and by 109% in the high-intensity group (P < .01), and absolute claudication distance increased by 61% (P < 0.01) and 63% (P < .01) in the low-intensity and high-intensity groups, respectively. Furthermore, both exercise programs elicited improvements (P < .05) in peak oxygen uptake, ischemic window, and health-related quality of life. The efficacy of low-intensity exercise rehabilitation is similar to high-intensity rehabilitation in improving markers of functional independence in PAD patients limited by intermittent claudication, provided that a few additional minutes of walking is accomplished to elicit a similar volume of exercise.

The impact of type 2 diabetes and peripheral arterial disease on quality of life

Peripheral arterial disease (PAD) is associated with impaired walking distance as the result of claudication and reduced quality of life (QOL). Diabetes mellitus (DM) is commonly associated with PAD. The combined effect of DM and PAD versus PAD alone on walking distance and QOL is not well understood. This prospective, descriptive study examined walking distance and QOL associated with DM and PAD compared with PAD alone. Walking distance was assessed by an exercise treadmill test to determine initial claudication distance and absolute claudication distance and by self-report using the Walking Impairment Questionnaire. QOL was measured using the Short Form-36. The overall sample consisted of 92 men and women with PAD and DM or PAD alone. Of the total sample, 74 participants had PAD with ABI less than 0.9 mm Hg and 18 subjects had PAD and uncontrolled DM with hemoglobin A1c 7.0 mg/dL or greater. The mean age was 72 years (standard deviation [SD] = 7) for the PAD only group and 75 years (SD = 8) (not significant) for the PAD and DM groups. Initial claudication distance was greater in subjects with PAD only (186.9 m, SD = 136.4) than in diabetic subjects with PAD (127.3 m, SD = 70.0, P = .01). Absolute claudication distance was higher in patients with PAD only (461.3 m, SD 308) than in diabetic subjects with PAD (279.1 m, SD = 100, P = .01). Self-reported walking speed was reduced in patients with DM and PAD compared with patients with PAD only (P = .05). Diabetic patients with PAD reported impaired role function (P = .007), general health (P = .03), and social function (P = .04) compared with patients with PAD only. We conclude that DM has a significant detrimental impact on walking distance and QOL in patients with PAD. These findings suggest that diabetic patients with PAD are at greater risk for experiencing social isolation, impaired role function, reduced overall perceptions of general health, and impaired functional capacity. Future studies with larger sample sizes are needed to identify factors that contribute to these perceptions in diabetic patients with PAD.

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, 3 h/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.

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

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). 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. 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. 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.

Exercise patterns and cardiovascular fitness of patients with peripheral arterial disease

Peripheral arterial disease (PAD) is characterized by walking impairment as the result of claudication, which is improved by exercise. Few studies have examined the impact of existing exercise patterns in community-dwelling patients with PAD on cardiovascular fitness and absolute claudication distance (ACD). This descriptive study examines exercise patterns, walking distance, and cardiovascular fitness in a sample of community-dwelling older adults with PAD. Approximately 50% of subjects reported walking 4 (+/-2) days per week for 38 +/- 24 minutes. ACD (exercisers = 459.9 +/- 272; non-exercisers = 351.2 +/- 266.3, P = .06) and initial claudication distance (exercisers = 198.5 +/- 139.7; non-exercisers = 138.7 +/- 95.8 P = .02) were similar between groups. The workload accomplished was approximately 4.1-4.7 metabolic equivalents. Resting heart rate (HR) was associated with initial claudication distance ( r = -.37, P = .001) and ACD ( r = -.46, P < .01) and was lower in the group of exercisers versus the non-exercisers ( P = .05). Mean resting SBP was elevated and continued to increase at peak exercise with no difference between groups ( P = .75). Quality of life was poor for both groups. Simultaneous multiple regression analysis was performed to determine predictors of peak exercise HR. The model included gender, age, current exercise, ankle-brachial index, coronary artery disease, beta blockers, ACD, and atrial fibrillation (R = 44%, P = .01). Higher peak exercise HR was associated with older age, female gender, no beta blockers, and greater ACD ( P < .01). The findings from this descriptive study demonstrate the need for larger long-term studies to address issues of exercise adherence and the psychologic and functional benefits of exercise.

β-Adrenergic Blocking Agents and Intermittent Claudication: Systematic Review

To clarify contradictions in past reports and the package inserts for beta-adrenergic blocking agents (beta-blockers) for patients with intermittent claudication (IC), we investigated the effects of beta-blockers in patients with IC using the systematic review technique. Data sources were randomized, controlled trials that investigated the effects of beta-blockers compared with the placebo or untreated group (controls) in patients with IC. Primary endpoints were walking distance and walking time, and secondary endpoints were ankle-brachial index (ABI) and calf blood flow. Nine trials were included in the analysis. Meta-analysis showed that there was a significant worsening in maximal walking distance and initial claudication distance in patients receiving beta-blockers, with standardized mean differences of -0.31 and -0.39 (95% confidence interval -0.58 to -0.04 and -0.73 to -0.06, P=0.03 and 0.02, respectively) compared with controls. There were no significant differences in maximal walking time (0.07, -0.24 to 0.37), time to onset of claudication (0.12, -0.23 to 0.47), ABI at rest (0.24, -0.30 to 0.78), calf blood flow at rest (0.00, -0.26 to 0.25), and calf blood flow after exercise (-0.23, -0.69 to 0.22). However, only one trial evaluated ABI, and the number of cases is increasing, suggesting that beta-blockers do not worsen ABI. There was no evidence that beta-blockers prescribed for patients with IC have unsuitable "precautions" in the package inserts. However, reluctance to administer beta-blockers to patients because they have IC is not appropriate.

Predictors of physical function in patients with peripherial arterial disease and claudication.

Limitation of walking due to claudication is the hallmark of peripheral arterial disease. The purpose of this secondary analysis was to identify biobehavioral predictors of physical function in peripheral arterial disease patients that included walking ability, gender, age, disease severity, environmental factors (social support), and medical comorbidity (arthritis). All subjects performed an exercise treadmill test to determine initial and absolute claudication distance. The sample consisted of 97 peripheral arterial disease patients, 71 (73%) men and 26 (27%) women, with a mean age of 73+/-8 years (range 52-90 years). Initial claudication distance occurred at 171.88+/-136.35 m. Absolute claudication distance was 421.03+/-286.37 m. A simultaneous multiple regression analysis was performed to determine predictors of physical function. The model accounted for 35% of the variance (p<0.001) and included personal characteristics (age, gender, years of education), severity of disease by ankle-brachial index, environmental factors of social support (marital status), absolute claudication distance, and arthritis. Education (p=0.011), absolute claudication distance (p=0.014), social support (p=0.026), arthritis (p=0.028), and age (p=0.033) were the strongest predictors of physical function. This study identifies biobehavioral factors that place peripheral arterial disease patients at greater risk for reduced physical function and provides a rationale for interventions that improve walking ability.

IS FIBRINOGEN AND D-DIMERS DETERMINATION USEFUL FOR PROGNOSIS OF DIABETIC POLYVASCULAR DISEASE

Claudication secondary to peripheral arterial disease leads to reduced mobility, limited physical functioning, and poor health outcomes. Disease severity can be assessed with quantitative clinical methods and qualitative self-perceived measures of quality of life. Limited data exist to document the degree to which quantitative and qualitative measures correlate. The current study provides data on the relationship between quantitative and qualitative measures of symptomatic peripheral arterial disease.This descriptive case series was set in an academic vascular surgery unit and biomechanics laboratory. The subjects were symptomatic patients with peripheral arterial disease patients presenting with claudication. The quantitative evaluation outcome measures included measurement of ankle-brachial index, initial claudication distance, absolute claudication distance, and self-selected treadmill pace. Qualitative measurements included the Walking Impairment Questionnaire (WIQ) and the Medical Outcomes Study Short Form-36 (SF-36) Health Survey. Spearman rank correlations were performed to determine the relationship between each quantitative and qualitative measure and also between the WIQ and SF-36.Included were 48 patients (age, 62 ± 9.6 years; weight, 83.0 ± 15.4 kg) with claudication (ABI, 0.50 ± 0.20). Of the four WIQ subscales, the ankle-brachial index correlated with distance (r = 0.29) and speed (r = 0.32); and initial claudication distance and absolute claudication distance correlated with pain (r = 0.40 and 0.43, respectively), distance (r = 0.35 and 0.41, respectively), and speed (r = 0.39 and 0.39 respectively). Of the eight SF-36 subscales, no correlation was found for the ankle-brachial index, initial claudication distance correlated with Bodily Pain (r = 0.46) and Social Functioning (r = 0.30), and absolute claudication time correlated with Physical Function (r = 0.31) and Energy (r = 0.30). The results of both questionnaires showed reduced functional status in claudicating patients.Initial and absolute claudication distances and WIQ pain, speed, and distance subscales are the measures that correlated the best with the ambulatory limitation of patients with symptomatic peripheral arterial disease. These results suggest the WIQ is the most specific questionnaire for documenting the qualitative deficits of the patient with claudication while providing strong relationships with the quantitative measures of arterial disease. Future studies of claudication patients should include both quantitative and qualitative assessments to adequately assess disease severity and functional status in peripheral arterial disease patients.

Response to exercise rehabilitation in smoking and nonsmoking patients with intermittent claudication

Background The purpose was to compare the changes in claudication pain, ambulatory function, daily physical activity, peripheral circulation, and health-related quality of life following a program of exercise rehabilitation in smoking and nonsmoking patients with peripheral arterial disease (PAD) limited by intermittent claudication. Methods and results Thirty-nine smokers (63 ± 4 pack-year smoking history; mean ± SE) and 46 nonsmokers (former smokers who had a 51 ± 7 pack-year smoking history who quit 14 ± 2 years prior to investigation) completed the study. The 6-month exercise rehabilitation program consisted of intermittent treadmill walking to near maximal claudication pain 3 days per week, with progressive increases in walking duration and intensity during the program. Measurements were obtained on each patient before and after rehabilitation. Following exercise rehabilitation the smokers and nonsmokers had similar improvements in these measures, as initial claudication distance increased by 119% in the smokers (P < .001) and by 97% in the nonsmokers (P < .001), and absolute claudication distance increased by 82% (P < .001) and 59% (P < .001) in the smokers and nonsmokers, respectively. Furthermore, exercise rehabilitation improved (P < .05) ambulatory function, daily physical activity, peripheral circulation, and health-related quality of life in the smokers and nonsmokers. Conclusion Exercise rehabilitation is an effective therapy to improve functional independence in both smoking and nonsmoking patients with PAD limited by intermittent claudication. Therefore, smokers with intermittent claudication are prime candidates for exercise rehabilitation because their relatively low baseline physical function does not impair their ability to regain lost functional independence to levels similar to nonsmoking patients with PAD.

Effects of Propionyl-Carnitine in Patients with Type 2 Diabetes and Peripheral Vascular Disease

To assess the efficacy of propionyl-carnitine (PC) in patients with type 2 diabetes and peripheral arterial disease (PAD). This was an open pharmacodynamic study. Twenty-four obese patients with type 2 diabetes and PAD (stage IIb) were enrolled in the study. After an initial run-in period of 7 days on a low-calorie diet (1600 +/- 150 kcal/day), patients received intravenous PC (600mg in 100mL saline solution Na/K 0.9%) twice daily for 10 days (T1). Treatment with PC produced statistically significant increases in maximal walking distance (30%; p < 0.05) and initial claudication distance (15%; p < 0.05) in 15 and eight patients, respectively. In addition, a decrease in dosage of oral antihyperglycaemic agents was observed in 21 patients at T1. No PC-related adverse effects were reported. This study showed that acute intravenous administration of PC in patients with type 2 diabetes with PAD improved PAD-related symptoms as well as glycaemic control.

Tissue (muscle) oxygen saturation (StO2): a new measure of symptomatic lower-extremity arterial disease.

Near-infrared spectroscopy provides a noninvasive method of measuring tissue oxygen saturation and has been used to monitor extremity compartment syndrome. Tissue O(2) saturation (StO(2)) is potentially useful in assessing patients with peripheral arterial disease (PAD). The purposes of this feasibility study are to (1) explore the diagnostic sensitivity of StO(2) in subjects with PAD and symptoms of intermittent claudication (IC) compared with normal subjects, and (2) correlate the change in StO(2) during and after exercise with the ankle brachial index (ABI) in patients with IC. Material and methods Forty-nine subjects, 35 normal and 14 PAD, from two centers were evaluated in a prospective cross-sectional analysis comparing StO(2) by using the InSpectra tissue spectrometer and ABI at rest (baseline) and after treadmill exercise. Measurements were obtained at baseline and peak exercise (normal subjects) and at baseline, initial claudication distance (ICD) and absolute claudication distance (ACD) in PAD subjects. Endpoint values were the mean of 15 data points. Times to 50% of StO(2) recovery to baseline (T(50)) and complete recovery to baseline (T(100)) were measured. Receiver-operator characteristic curves were constructed to assess the sensitivity/specificity values associated with various StO(2) cut-points. The PAD patients were older (P =.0002) and 57% were male, compared with 37% males in the normal group. The ABI was 0.68 +/- 0.14 in PAD patients versus 1.14 +/- 0.08 in normal subjects (P <.0001). The baseline StO(2) was 65% in both groups. The peak exercise StO(2) was significantly lower and the absolute change in StO(2) and the percent change in StO(2) were significantly greater in PAD patients (P < 0.45). The T(50) and T(100) were longer in the PAD patients compared to normal subjects (P =.0001 and.002, respectively). A T(50) of >70 seconds yielded a sensitivity of 89% and a specificity of 85% for PAD. StO(2) is a new and potentially useful technique to evaluate patients with PAD. Resting StO(2) was similar in PAD-IC subjects and normals. There was a significantly greater drop in StO(2) and longer recovery times in PAD-IC subjects. Interestingly, StO(2) at the ICD and ACD was similar. StO(2) offers a different and perhaps more appropriate end point for diagnosis and monitoring of the management of patients with PAD, and may offer additional insight into the pathophysiology of exercise-induced muscle ischemia and its recovery.

THE RESPONSE TO EXERCISE REHABILITATION IN SMOKING AND NON-SMOKING PATIENTS WITH INTERMITTENT CLAUDICATION

PURPOSE To compare the changes in claudication pain, ambulatory function, daily physical activity, peripheral circulation, and health-related quality of life following a program of exercise rehabilitation in smoking and non-smoking patients with peripheral arterial disease (PAD) limited by intermittent claudication. METHODS Thirty-nine smokers (63 ± 4 pack-year smoking history; mean ± SE) and 46 non-smokers (former smokers who had a 51 ± 7 pack-year smoking history who quit 14 ± 2 years priorto investigation) completed the study. The 6-month exercise rehabilitation program consisted of intermittent treadmill walking to near maximal claudication pain three days per week, with progressive increases in walking duration and intensity during the program. RESULTS At baseline, the smokers had impaired (p <0.05) claudication pain, ambulatory function, daily physical activity, peripheral circulation, and health-related quality of life compared to the non-smokers. Following exercise rehabilitation, initial claudication distance increased by 119% in the smokers (p <0.001) and by 97% in the non-smokers (p <0.001), and absolute claudication distance increased by 82% (p <0.001) and 59% (p <0.001) in the smokers and non-smokers, respectively. Furthermore, exercise rehabilitation improved (p <0.05) ambulatory function, daily physical activity, peripheral circulation, and health-related quality of life in the smokers and non-smokers. All of the changes following the exercise rehabilitation program were similar between the two groups. CONCLUSION Exercise rehabilitation is an effective therapy to improve functional independence in both smoking and non-smoking PAD patients limited by intermittent claudication. Therefore, smokers with intermittent claudication are prime candidates for exercise rehabilitation because their relatively low baseline physical function does not impair their ability to regain lost functional independence to levels similar to non-smoking PAD patients.

Reproducibility of constant-load treadmill testing with various treadmill protocols and predictability of treadmill test results in patients with intermittent claudication

Background: Most trials on the reliability of constant-load treadmill testing use one pair of treadmill settings (speed, grade) only. The question of whether the results can be applied to tests with different settings is left open. Also, claudication distances measured with differing settings are not comparable, rendering the comparison of the results from different trials difficult. This study evaluates the reliability of constant-load testing with various workloads and compares them with claudication distances achieved with walking at normal speed on level ground but also evaluates whether metabolic equivalent (MET) normalization can be used to translate the results of different treadmill tests into each other. Methods: Fifteen patients with claudication underwent repeated treadmill testing with different treadmill settings, including speeds of 2.0, 3.2, and 4.0 km/h (1.25, 2.0, and 2.5 mph, respectively) and grades of 0% and 12%. The walking capacity was also tested on level ground with a speed chosen by the individual patient. Results of virtual treadmill tests with all possible combinations of the speeds and the grades used were predicted from real tests, with MET normalization. The relationship between real and predicted claudication distances was tested with regression modeling. Results: Reliability coefficients (RCs) for the absolute claudication distance (ACD) were superior to RCs for the initial claudication distance. RCs for ACD ranged between 0.61 and 0.95, with increasing values found with increasing workloads. The best coefficients for the regression of measured on predicted claudication distances were achieved with a model on the basis of a power function ( r = 0.963). The model was only appropriate for the prediction of group mean results from clinical trials but cannot be applied to single patient data. For proof of concept, the model was tested with six published studies in which the claudication distances of a patient sample were double treadmill tested with different workloads. The result of the second test was predicted from the first test, and estimated and measured claudication distances were compared. The mean difference (all trials) was 7.9%, whereas the maximum difference amounted to 16.5%. Conclusion: For an optimal treadmill test reliability, higher workloads should be used and ACD should be preferred over initial claudication distance. MET normalization provides the basis for the comparability of treadmill test results achieved with different test conditions. (J Vasc Surg 2002;36:83-8.)

A Randomised, Double Blind, Placebo-controlled Study to Determine the Efficacy of Immune Modulation Therapy in the Treatment of Patients Suffering from Peripheral Arterial Occlusive Disease with Intermittent Claudication

Objectives: this study examined the effect of immune modulation therapy (IMT) on claudication distancesMaterials and methods: a double-blind placebo controlled trial was performed on patients with disabling intermittent claudication with randomisation stratified for short and long distance IC. For IMT, following exposure to UV light, oxidisation and 42.5°C, 10ml of citrated autologous blood was administered by intra-muscular injection. One course consisted of 6 injections in 3-weeks followed by 3-weeks rest. Patients received 2, 3 or 4 courses depending on response. The primary end-point was the number of responders (>50% increase in initial claudication distance (ICD)) in each group. Secondary end-points included percentage changes in ICD and change in quality of life.Results: at week 24, there were more responders in the IMT group (20/31, 65%) compared to placebo (16/39, 41%) (p=0.06). In the subgroup of short distance claudicants this difference reached significance (IMT 17/26, 65%) (Placebo12/33, 36%) (p=0.04). The median increase in ICD was significantly greater in the IMT group (81%) compared to placebo (44%, p=0.04). These results were supported by quality of life measurements.Conclusions: IMT is a safe and apparently effective treatment for patients with short distance claudication.

Exercise capacity and Doppler pressure measurements in symptomatic peripheral arterial obstructive disease.

Doppler pressure measurements are a useful diagnostic tool in peripheral arterial obstructive disease. The aim of our study was to determine whether these pressure values do predict the degree of impairment of the walking capacity in symptomatic patients. We compared the claudication distances (CDI: initial claudication distance, CDA: absolute claudication distance) of 939 patients (63 +/- 11 years) with stable intermittent claudication (Fontaine IIb) with the ankle pressure values at rest (APR) and after exercise (APE), with the ankle/brachial pressure index at rest (ABIR) and after exercise (ABIE), and with the ratio (ABIRATIO = ABIE/ABIR). Ankle systolic pressures were obtained using an 8 MHz Doppler probe. CD was measured by a treadmill test at constant-load conditions (3 km/hr; inclination 12%). Brachial systolic pressures were obtained using an automated blood pressure monitor. The values of the objectively worse leg were correlated with CDI and CDA. Low Doppler pressure values were not accompanied by significantly shorter walking distances in symptomatic patients. The resting pressure values (APR, ABIR) did not correlate with the claudication distances (CDI: 54 +/- 31 m; CDA: 87 +/- 41 m). For the exercise values (APE, ABIE), even a very slight inverse correlation with the claudication distances was found. In addition, the correlation between the pressure index ratio and the walking distances (ABIRATIO vs. CDI: r = -0.25, p < 0.01; ABIRATIO vs. CDA: r = -0.20, p < 0.01) was inverse, too, but slightly more pronounced. In patients with intermittent claudication the ankle artery pressures and the indices derived from these pressure values do not predict the walking distance. Therefore, the decision for angioplasty or bypass surgery should be made with regards to the impairment of quality of life rather than Doppler pressure values.