Factors Associated with Sedentary Behavior in Patients with Intermittent Claudication.

OBJECTIVES: Time spent in sedentary behavior has been associated with cardio-metabolic risk factors in the general population and in patients with symptomatic peripheral artery disease (PAD). Given the association of sedentary behavior and poor health outcomes, it is important to identify factors associated with sedentary behavior in these patients. The aim of this study was to identify factors associated with the sedentary time in patients with symptomatic PAD. METHODS: The sample included 297 patients with symptomatic PAD. Sedentary behavior was assessed using a step activity monitor and the patients were divided into tertiles. Demographic data, body mass index, comorbid conditions, and measures of severity of PAD (ankle brachial index, ischemic window, claudication measurements, peak oxygen uptake and walking economy) were obtained. RESULTS: Patients in the highest tertile (i.e. more sedentary) had a higher body mass index and a higher prevalence of diabetes mellitus, metabolic syndrome, and obesity than patients in the lowest tertile, whereas their peak walking time, peak oxygen uptake, and walking economy were lower (p < .05 for all). Using multiple regression procedures, the factors associated with the sedentary time were male sex (b = .217, R2 = .180, p = .001), body mass index (b = .154, R2 = .059, p = .013), peak walking time (b = -.360, R2 = .066, p ≤ .001), and walking economy (b = -.187, R2 = .142, p = .004). CONCLUSION: In patients with symptomatic PAD, greater time spent in sedentary behavior was found in men, and in patients with higher body mass index, lower peak walking time, and lower walking economy.

Walking Economy is Impaired in Older Men and Women with Type 2 Diabetes.

OBJECTIVE: We compared the walking economy in older participants with and without type 2 diabetes. METHODS: Walking economy was determined in 115 older participants with type 2 diabetes and 130 older control participants without diabetes by continuously measuring oxygen uptake during a treadmill test in which the work rate was at a constant speed of 2 mph and a grade of 0% for a duration of 10 minutes. Participants also completed a Balke treadmill protocol for the determination of peak oxygen uptake, defined as the highest oxygen uptake value attained during the final work stage attained. Fractional utilization was then calculated as the walking economy oxygen uptake divided by peak oxygen uptake, expressed as a percentage. RESULTS: Compared to those without diabetes, participants with type 2 diabetes were older (p=0.042), had higher prevalence of men (p=0.034), obesity (p=0.010), chronic kidney disease (p=0.020), peripheral artery disease (p=0.024), and had a higher body mass index (p=0.025), and waist/hip ratio (p=0.006). After adjusting for these variables, the participants with diabetes had higher walking economy (p<0.001), fractional utilization (p<0.001), and lower peak oxygen uptake (p<0.001) than those without diabetes (p<0.001). CONCLUSIONS: Older men and women with type 2 diabetes are less economical when they ambulate at a given speed than compared to control participants without diabetes, independent of their greater co-morbid burden. The impaired walking economy in the diabetic participants is further magnified by their lower aerobic fitness, thereby leading to a higher fractional utilization of oxygen consumed during a given walking task.

Cannulated versus non-cannulated cancellous screw fixation for femoral neck fractures: a synthetic bone biomechanical study.

PURPOSE: To compare the compressive strength of cannulated versus non-cannulated cancellous screws for undisplaced femoral neck fractures in synthetic bones. METHODS: 18 synthetic proximal femurs simulating an AO B1 valgus impacted femoral neck fracture in osteoporotic bone were used. The fracture angles were between 55º and 63º (Pauwels grade 2). Fixation was made using 6.5-mm non-cannulated screws (n=6), 6.5-mm cannulated screws (n=6), or 7.3-mm cannulated screws (n=6). A custom-built jig was designed to guide the insertion of the screws in an identical triangular configuration. Screws were tightened by a single operator using a torque-measuring screwdriver. The femoral head was subjected to progressive axial loading at 5 mm/min. The load to failure and displacement were recorded. RESULTS: The 3 groups did not differ significantly except that the load to failure was higher in the construct with 6.5-mm non-cannulated screws than that with 6.5-mm cannulated screws (1222 N vs 1008 N, p=0.003). CONCLUSION: The compressive strength of a synthetic bone hip fracture model fixed with non-cannulated screws was higher than that of cannulated screws of the same diameter.

Interfragmentary compression profile of 4 headless bone screws: an analysis of the compression lost on reinsertion.

PURPOSE: To evaluate the interfragmentary compression force generated by 4 different types of headless compression screws and to examine the effects of removal and reinsertion of the screw. METHODS: We chose foot bones rather than scaphoids for the model because they were larger and would enable comparison of 2 screw designs in the same bone, thereby controlling for the effect of interspecimen variability. A transverse osteotomy was made in 10 fresh-frozen cadaveric navicular bones and 10 medial cuneiforms. A load cell was used to measure compression between the 2 fragments as a screw was inserted across the fracture. Each bone was tested twice, with an Acutrak Mini (Acumed, Hillsboro, OR; n = 10) and an SBi AutoFIX screw (SBi, Morrisville, PA; n = 10) or an Extremifix (Osteomed, Addison, TX; n = 10) and a Barouk screw (Depuy, Warsaw, IN; n = 10). Compression was recorded at initial insertion and on removal and reinsertion of the screw twice to the same position. Compression was also measured after one additional full turn further than the initial position. RESULTS: The mean interfragmentary compression generated by the Acutrak Mini screw was greater than that of the SBi AutoFIX screw (96 N vs 22 N). There was a trend toward a greater mean compression generated by the Extremifix screw compared to the Barouk screw (85 N vs 22 N). There was a significant loss of compression upon removal and reinsertion of the screws. An additional full turn of the screw was able to re-establish a large proportion of the original compression. CONCLUSIONS: The compression forces achieved by headless screw systems appeared to vary according to the screw design, depth of insertion, and the quality of the bone. Substantial compression was lost if the screw was removed and replaced. Some screw designs appeared to require a greater depth of insertion to achieve effective compression, and the number of additional turns required to re-establish compression might vary according to the thread design. CLINICAL RELEVANCE: Surgeons should be aware of the compression profile of each screw design and the effect of screw removal and reinsertion in the clinical setting of small bone fixation.

Predictors of change in walking distance in patients with peripheral arterial disease undergoing endovascular intervention.

BACKGROUND: Endovascular treatment of peripheral artery disease is becoming frequent, yet the clinical factors which predict ambulatory outcomes are not known. HYPOTHESIS: To identify predictors of change in walking distance in patients who underwent endovascular intervention for their lower extremity peripheral arterial disease (PAD). METHODS: A total of 134 patients underwent lower extremity peripheral arterial intervention, 52 patients were contacted via phone between 1 and 36 months (a mean of 22 mo) after their initial procedure. The remaining 82 patients were excluded due to the following reasons: death (n = 13), contact information was not available (n = 50), and refusal to participate in the follow-up (n = 19). RESULTS: The patients were 63 +/- 12 years old (mean +/- standard deviation [SD]), 46% were male, 47% were diabetics, 49% had coronary artery disease, of whom 29% had prior revascularization, and 22% had coronary artery bypass grafts (CABG). The disease severity described by Fontaine classification were as follows: 44.2% were in stage II, 15.4% were in stage III, and 40.4% were in stage IV. Walking distance was improved in 21% of patients, worsened in 73% of patients, and unchanged in 6% of patients. Stepwise multiple regression demonstrated that patients who started to walk or exercise (R = 0.372, P < 0.012) and who had a prior history of CABG (R = 0.467, P < 0.006) were the only independent predictors of the change in walking distance at follow-up. Those who started to walk reported worse walking distance at follow-up, while those with a history of CABG reported better walking distance at follow-up. CONCLUSION: CABG prior to endovascular intervention is predictive of favorable change in walking distance in patients with PAD at follow-up. Therefore, post-CABG patients are good candidates for exercise rehabilitation and risk factor modification.

An audit of the current consent practices of consultant orthodontists in the UK.

OBJECTIVE: To collect information on the current consent practices of consultant orthodontists for orthodontic and joint orthognathic treatment. DESIGN: Postal questionnaire. SUBJECTS AND METHODS: The questionnaire was sent to all 222 consultant orthodontists held on the database of the British Orthodontic Society. The questionnaire consisted of five multi-part questions requiring tick-box responses. OUTCOME: A total of 199 questionnaires were returned. RESULTS: Written information on orthodontic treatment was provided by 56 per cent of respondents whilst 41 per cent obtained written consent. Written information on joint orthognathic treatment was provided by 47.5 per cent of respondents, whilst 20 per cent obtained joint written consent. Most who obtained written consent for orthodontics and joint orthognathic treatment used 16 years as an appropriate age for patients to provide their own consent. CONCLUSIONS: Consent practice amongst consultant orthodontists varies, with 35 per cent providing neither written information nor seeking written consent prior to orthodontic or joint orthognathic treatment.

Body fat distribution and flow-mediated endothelium-dependent vasodilation in older men.

OBJECTIVE: Recent studies indicate that abdominal fat accumulation, in particular intra-abdominal fat, is related to impaired endothelial function in young healthy volunteers. The aim of this study was to examine whether the distribution of body fat depots is related to impaired endothelial function in older men. METHODS: Cross-sectional sample of 38 older (68+/-1 y) sedentary (VO(2max)=2.4+/-0.1 l/min) men. Flow-mediated endothelial dependent vasodilation (EDD) was assessed in the brachial artery in response to reactive hyperemia using high-resolution ultrasound. Abdominal subcutaneous and visceral fat depots were assessed by computed tomography scan (CT-scan) at the L(4)-L(5) region in the supine position. Percentage body fat was assessed via dual-energy X-ray absorptiometry (DEXA). RESULTS: Flow-mediated percentage change in brachial artery was 7.6+/-0.7%, suggesting an impaired flow-mediated EDD. Using simple linear regression analysis, there were no statistically significant relationship observed between flow-mediated EDD and the indices of total and abdominal adiposity (percentage body fat=29.3+/-0.9%, r=-0.11; total abdominal fat area=465+/-23 cm(2), r=-0.1; intra-abdominal fat area=200+/-14 cm(2), r=-0.14; subcutaneous fat area=265+/-13 cm(2), r=-0.05; BMI=29.3+/-0.9 kg/m(2), r=-0.07; and waist to hip ratio=0.98+/-0.01, r=-0.20). CONCLUSION: These findings suggest that in older sedentary men there is no clear correlation between adiposity and body fat distribution and impairment of flow-mediated endothelium dependent vasodilation.

Impaired balance and higher prevalence of falls in subjects with intermittent claudication.

BACKGROUND: The purpose of this study was to determine whether peripheral arterial disease (PAD) subjects have impaired balance and a higher prevalence of falls than non-PAD controls and to determine whether balance and falls are related to the severity of PAD and functional status. METHODS: A total of 367 PAD subjects (aged 68 +/- 1 years; mean +/- SEM) and 458 non-PAD controls (aged 67 +/- 1 years) were recruited. Unipedal stance time, history of ambulatory stumbling and unsteadiness, and history of falling were recorded. Additionally, subjects were characterized on age, ankle/brachial index (ABI), anthropometry, measured and self-reported ambulatory function, and monitored daily physical activity. RESULTS: Unipedal stance time was 28% shorter ( p <.001) in the PAD subjects than in the non-PAD controls (15.9 +/- 0.9 vs 22.1 +/- 1.0). History of ambulatory stumbling and unsteadiness was 86% more prevalent ( p <.001) in the PAD group (150/367 = 41%) than in the controls (101/458 = 22%), and history of falling was 73% more prevalent ( p <.001) in the PAD subjects (95/367 = 26%) than in the controls (69/458 = 15%). Within the PAD group, 6-minute walk distance, self-reported ambulatory function, and daily physical activity were significantly related to the balance and falling measures ( p <.05), whereas ABI was unrelated ( p >.05). CONCLUSIONS: Compared with the controls, PAD subjects with intermittent claudication had impaired balance and a greater likelihood of falling, both of which were associated with ambulatory function and daily physical activity.

Exercise rehabilitation improves functional outcomes and peripheral circulation in patients with intermittent claudication: a randomized controlled trial.

OBJECTIVE: To determine the effects of a 6-month exercise program on ambulatory function, free-living daily physical activity, peripheral circulation, and health-related quality of life (QOL) in disabled older patients with intermittent claudication. DESIGN: Prospective, randomized controlled trial. SETTING: University Medical (Center and Veterans Affairs Medical Center, Baltimore, Maryland. PARTICIPANTS: Thirty-one of 61 patients with Fontaine stage II peripheral arterial occlusive disease (PAOD) were randomized to exercise rehabilitation and 30 to usual-care control. Three patients from the exercise group and six patients from the control group dropped out, leaving 28 and 24 patients, respectively, completing the study in each group. INTERVENTION: Six months of exercise rehabilitation. MEASUREMENTS: Treadmill distance walked to onset of claudication and to maximal claudication, ambulatory function, peripheral circulation, perceived QOL, and daily physical activity. RESULTS: Compliance with the exercise program was 73% of the possible sessions. Exercise rehabilitation increased treadmill distance walked to onset of claudication by 134% (P < .001) and to maximal claudication by 77% (P < .001), walking economy by 12% (P = .003), 6-minute walk distance by 12% (P < .001), and maximal calf blood flow by 30% (P < .001). Changes in distance walked to maximal pain correlated with changes in walking economy (r = -.50, P = .013) and changes in maximal calf blood flow (r = .38, P = .047). Exercise rehabilitation increased accelerometer-derived daily physical activity by 38% (P < .001); this change correlated with the change in distance walked to maximal pain (r = .45, P = .020). These improvements were significantly better than the changes in the control group (P < .05). CONCLUSION: Improvements in claudication following exercise rehabilitation in older PAOD patients are dependent on improvements in peripheral circulation and walking economy. Improvement in treadmill claudication distances in these patients translated into increased accelerometer-derived physical activity in the community, which enabled the patients to become more functionally independent.

Altered gait profile in subjects with peripheral arterial disease.

The purpose of this study was to determine whether peripheral arterial disease (PAD) subjects had impaired temporal and spatial gait characteristics compared to non-PAD controls at preferred and rapid self-selected walking paces. A total of 28 PAD subjects with intermittent claudication (age = 71 +/- 1; mean +/- SEM) and 15 non-PAD controls with at least one cardiovascular risk factor but no ambulatory leg pain (age = 71 +/- 1) were recruited. Gait parameters consisting of velocity, cadence, stride length, swing time, stance time, single-support time, double-support time, and base of support were recorded at the preferred and rapid walking paces. At the rapid walking pace, velocity was 22% slower (p < 0.001) in the PAD subjects compared with the non-PAD controls (99.9 +/- 3.3 vs. 117.5 +/- 5.3 cm/s) due to an 8% (p = 0.019) slower cadence (99.9 +/- 1.7 vs. 103.3 +/- 2.4 steps/min) and a 14% (p < 0.001) shorter stride length (119.8 +/- 2.9 vs. 135.8 +/- 4.2 cm/stride). The PAD subjects spent 5% less of the gait cycle in the swing phase (p = 0.006) and 3% more in stance (p = 0.006) than their non-PAD counterparts. During the stance phase, the PAD subjects spent 5% less of the gait cycle in single-stance (p=0.004) and 16% more in double-stance (p = 0.007). Similar results were obtained at the preferred walking pace. In conclusion, compared with the controls, PAD subjects adopted an ambulatory pattern that favored greater gait stability at the expense of greater walking speed at either their preferred or rapid self-selected paces.

Lack of functional benefits following infrainguinal bypass in peripheral arterial occlusive disease patients.

This study aimed to determine whether peripheral arterial occlusive disease (PAOD) patients with critical limb-threatening ischemia experienced functional benefits following lower extremity revascularization. Twenty ambulatory patients (aged 68 +/- 7 years) underwent infrainguinal revascularization to alleviate their symptoms. Peripheral hemodynamic and functional measures were obtained on each patient 1 week prior to and 3-4 months following revascularization. Critical limb-threatening ischemia was alleviated by surgery in all patients because the ankle/brachial index (ABI) increased 133% (p < 0.001) from 0.33 +/- 0.06 to 0.77 +/- 0.09. Despite the marked peripheral hemodynamic improvement following revascularization, little gains were noted in functional measures. The 6-min walking distance was unchanged (p = 0.739) from 85 +/- 9 m to 101 +/- 11 m. Additionally, the free-living daily physical activity, measured by an accelerometer worn over a 2-day period, was unchanged (p = 0.996) from 214 +/- 46 kcal/day to 215 +/- 83 kcal/day. In contrast, self-perceived ambulatory function improved by 142% to 271% (p < 0.001), and self-perceived physical activity increased 134% to 156% (p < 0.001). In conclusion, limb salvage following infrainguinal bypass does not translate into improvements in measured ambulation or in measured physical activity in PAOD patients, even though the patients perceive these measures to be better.

Decreased NADH dehydrogenase and ubiquinol-cytochrome c oxidoreductase in peripheral arterial disease.

Peripheral arterial disease (PAD) is associated with muscle metabolic changes that may contribute to the disability in these patients. However, the biochemical defects in PAD have not been identified. The present study was undertaken to test the hypothesis that PAD is associated with specific defects in skeletal muscle electron transport chain activity. Seventeen patients with PAD and nine age-matched controls underwent gastrocnemius muscle biopsies. There were no differences in the mitochondrial content per gram of skeletal muscle as assessed by citrate synthase activity between the PAD patients and the control subjects. Skeletal muscle NADH dehydrogenase activity was decreased by 27% compared with controls when expressed per unit of citrate synthase activity. Expression of enzyme activities normalized to cytochrome c-oxygen oxidoreductase activity confirmed a 26% decrease in NADH dehydrogenase activity and also demonstrated a 38% decrease in ubiquinol-cytochrome c oxidoreductase activity. Thus PAD is associated with specific changes in muscle mitochondrial electron transport chain activities characterized by relative decreases in NADH dehydrogenase and ubiquinol-cytochrome c oxidoreductase activities, which may contribute to the metabolic abnormalities and decreased exercise performance in these patients.

Fibrinolytic response to acute exercise in patients with peripheral arterial disease.

PURPOSE: Elevations in tissue plasminogen activator (tPA) are postulated to protect against atherothrombotic events during exercise. However, fibrinolytic response to repetitive bouts of symptom-limited exercise is unknown in peripheral arterial disease (PAD) patients, a population with impaired fibrinolysis and increased risk for ischemic events. The purpose of the present study was to evaluate the fibrinolytic response to repetitive bouts of symptom-limited exercise in PAD patients. METHODS: Nine (8 male, 1 female) patients with Fontaine State II PAD were studied. Fasting blood samples for determination of tPA and plasminogen activator inhibitor (PAI-1) were obtained into an acidified citrate solution via an indwelling venous catheter before, immediately after, 30 min after, and 60 min after submaximal treadmill walking. Patients walked intermittently at 65% of maximal intensity achieved on a previous graded exercise test until 30 min of exercise was achieved. RESULTS: Exercise increased tPA activity by 180% (0.5 +/- 0.16 IU.mL(-1) baseline, 1.4 +/- 1.2 IU.mL(-1) postexercise), and decreased PAI-1 activity by 40% (20.6 +/- 5.5 AU.mL(-1) baseline, 11.8 +/- 6.2 AU.mL(-1) postexercise), without changing tPA or PAI-1 antigen. Notably, plasma tPA activity levels 1 h after exercise remained elevated by 80%, whereas PAI-1 activity remained decreased by 49%. The decrease in PAI-1 significantly (P < 0.05) correlated with oxygen uptake (VO(2)) during submaximal exercise (r = -0.77). CONCLUSION: These findings demonstrate that repetitive bouts of symptom-limited exercise produce a substantial improvement in the fibrinolytic profile of PAD patients, which persists at least 1 h after exercise cessation.

Lower extremity strength deficits in peripheral arterial occlusive disease patients with intermittent claudication.

The purposes of this study were to quantify the degree and distribution of lower extremity weakness in patients with peripheral arterial occlusive disease (PAOD) compared to apparently healthy older patients and to determine if performance of a simple functional measure correlates with lower extremity strength. Older patients (n = 46), 31 with PAOD (mean age = 69.9 years; mean ankle-brachial index = 0.67) and 15 without PAOD (mean age = 62.6 years; mean ankle-brachial index = 1.20), underwent isometric strength testing of hip, knee, and ankle musculature. In patients with PAOD, dorsiflexion strength was 15% lower (p < 0.05) in the more affected limb (55 +/- 4 Newton-meters; mean +/- SE) versus the less affected limb (65 +/- 5 Newton-meters). Overall, the dorsiflexor muscles of the more affected extremity were 22% weaker (p < 0.05) in the PAOD group than in the non-PAOD group (73 +/- 6 Newton-meters). No other significant differences in strength were found between the PAOD and the healthy elderly groups or between the more affected and less affected limbs in the PAOD patients. The time to perform five sequential sit-to-stand transfers using an armless chair was 23% greater (p < 0.01) in the PAOD group (13.0 +/- 0.5 s) than in the healthy elderly (10.7 +/- 0.9 s). In the PAOD patients, dorsiflexor strength was correlated with chair stand time (r = -0.37, p < 0.05). The authors conclude that PAOD patients with intermittent claudication are functionally limited by dorsiflexion weakness, impairing their ability to perform tasks requiring distal lower extremity strength.

Effects of exercise rehabilitation on endothelial reactivity in older patients with peripheral arterial disease.

Peripheral arterial disease (PAD) is a major cause of morbidity and mortality. Endothelial function, which is a measure of vascular health, is impaired in patients with PAD. We examined the effects of 6 months of aerobic exercise rehabilitation on brachial artery endothelial function, assessed using high-frequency ultrasonography, and calf blood flow in 19 older PAD patients (age 69 +/- 1 years, mean +/- SEM) with intermittent claudication (ankle to brachial artery index of 0.73 +/- 0.04). After exercise, the time to onset of claudication pain increased by 94%, from 271 +/- 49 to 525 +/- 80 seconds (p <0.01), and the time to maximal claudication pain increased by 43%, from 623 +/- 77 to 889 +/- 75 seconds (p <0.05). Exercise rehabilitation increased the flow-mediated brachial arterial diameter by 61%, from 0.18 +/- 0.03 to 0.29 +/- 0.04 mm (p <0.005), as well as the relative change in brachial arterial diameter from the resting state by 60%, from 4.81 +/- 0.82% to 7.97 +/- 1.03% (p <0.005). Maximal calf blood flow (14.2 +/- 1.0 vs 19.2 +/- 2.0 ml/100 ml/min; p = 0.04), and postocclusive reactive hyperemic blood flow (9.8 +/- 0.8 vs 11.3 +/- 0.7 ml/100 ml/min; p = 0.1) increased 35% and 15%, respectively. In conclusion, exercise rehabilitation improved ambulatory function, endothelial-dependent dilation, and calf blood flow in older PAD patients with intermittent claudication.

The relationship between history of falling and physical function in subjects with peripheral arterial disease.

The purpose of this study was to determine whether peripheral arterial disease (PAD) subjects with a history of falling had more impaired physical function than their non-falling counterparts. A total of 120 PAD subjects (26%) who had fallen over the past year and 346 PAD subjects (74%) who had not fallen were evaluated. Additionally, subjects were characterized on physical function, consisting of balance, strength, ambulatory function, and monitored physical activity, as well as PAD-specific measures of ankle/brachial pressure index (ABPI) and treadmill claudication distances. Full-tandem stance time was 19% shorter (p < 0.001) in the fallers than in the non-fallers (7.2 +/- 0.3 vs 8.9 +/- 0.1 s; mean +/- SEM), and the self-reported ability to climb stairs was 36% lower (27 +/- 4 vs 42 +/- 2%). Furthermore, the fallers were 126% more likely (p < 0.001) to report ambulatory stumbling and unsteadiness, took 14% longer (p = 0.022) to perform five sequential sit-to-stand transfers using an armless chair, covered 16% shorter distance (p < 0.001) during a 6-min walk test, and were 25% less physically active than the non-fallers. The groups had similar ABPI and treadmill claudication distances (p < 0.05). A history of falling was independently related to the self-reported ability to climb stairs, the full-tandem stance time, self-reported ambulatory stumbling and unsteadiness, and daily physical activity (multiple R = 0.47, p < 0.001). In conclusion, impairments in multiple domains of physical function were associated with a history of falling in PAD subjects with intermittent claudication. Furthermore, the link between poor physical function and falling was independent of PAD severity.

Comorbidities and exercise capacity in older patients with intermittent claudication.

Patients with peripheral arterial disease (PAD) and intermittent claudication often have coronary artery disease (CAD) and other comorbid medical problems. There is a paucity of information on the impact of coexistent medical conditions on exercise capacity and functional status in patients with PAD. This study examined the impact of CAD, diabetes, cigarette smoking, prior peripheral surgical revascularization and other medical conditions on claudication pain times and peak oxygen capacity (VO2) during maximal effort treadmill testing in 119 male outpatient volunteers (ankle-brachial index (ABI) of 0.65 +/- 0.2, mean +/- SEM) with a history of Fontaine Stage II PAD. Smoking status was significantly related to ambulatory function. Current smokers had a lower peak VO2 expressed in l/min than either former or never smokers (ANCOVA adjusted for age, p = 0.003). However, after adjustment for body weight, there was only a trend for a difference in peak VO2 between current (13.2 +/- 0.5 ml/kg per min), former (14.2 +/- 0.4 ml/kg per min) and never (15.4 +/- 1.0 ml/kg per min) smokers (ANCOVA, p = 0.10). Current smokers had a shorter time to onset of claudication pain (p = 0.023) and shorter maximal claudication pain times (p = 0.029) than former or never smokers (p = 0.023). The ABI 1 min after cessation of exercise was also lower in smokers compared to former and never smokers (p = 0.018). There were no significant differences in functional performance measures or time to recovery from maximal claudication pain when patients were categorized on the presence or absence of CAD, diabetes, peripheral revascularization, arthritis, hypertension or dyslipidemia. Therefore, smoking adversely affected exercise capacity in these PAD patients, whereas the presence of CAD, diabetes and other medical problems had a relatively minor impact on exercise capacity. In conclusion, the relatively minor impact of comorbid medical conditions on walking ability in patients with PAD reflects the overwhelming limitation in ambulatory function due to the claudication pain.

Exercise for patients with peripheral artery disease.

Peripheral artery disease is a significant health concern among the elderly and will likely become more common. Nonsurgical management, such as modification of risk factors for atherosclerosis, can improve the health of asymptomatic patients and those with intermittent claudication. Exercise rehabilitation, with or without pharmacotherapy, is highly effective in improving health and ambulation in patients with intermittent claudication. Percutaneous transluminal angioplasty and arterial reconstruction may be required for more severely affected patients.

Assessment of physical function and exercise tolerance in older adults: reproducibility and comparability of five measures.

This study examined the reproducibility and comparability of five measures of function and exercise tolerance. The test battery and questionnaire on function and physical activity were administered twice, 7-10 days apart to 38 men and 12 women aged 54-80 years at the Baltimore Veterans Affairs Medical Center. Tests included fast pace 4 and 20-meter walks, 6-minute and graded treadmill walks, and a seated step test. All tests demonstrated good reproducibility with Pearson and intraclass correlation coefficients ranging from 0.84 to 0.98, and percent differences on retest ranging from 4 to 11%. Although correlations between different tests were all significant (range 0.34-0.89), comparison of performance ranks and linear regression analyses indicated that the short fast walks and seated step test may not be suitable substitutes for treadmill or long self-paced corridor walks. Only 28% had the same quintile performance ranking on the step test as on the treadmill walk, and 36% had rankings 2 or more points apart. The fast 20m walk shows the most promise as a low-level alternative to the 6-minute walk; performances had a correlation of 0.73, 82% of ranks were within one point, and 20m speed explained 42% of the variance in distance covered. More development is needed for comprehensive assessment of exercise tolerance in older adults; the 6-minute walk did not adequately discriminate fitness level in persons who walk regularly, and the treadmill posed problems for those with walking difficulty.

Improved functional outcomes following exercise rehabilitation in patients with intermittent claudication.

BACKGROUND: The purposes of this study were to identify predictors of increased claudication distances following exercise rehabilitation in peripheral arterial occlusive disease (PAOD) patients with intermittent claudication and determine whether improved claudication distances translated into increased free-living daily physical activity in the community setting. METHODS: Sixty-three patients were recruited (age, 68+/-1 years, mean +/- standard error). Patients were characterized on treadmill claudication distances, walking economy, peripheral circulation, cardiopulmonary function, self-perceived ambulatory function, body composition, baseline comorbidities, and free-living daily physical activity before and after a 6-month treadmill exercise program. RESULTS: Exercise rehabilitation increased distance to onset of claudication pain by 115% (178+/-22 m to 383+/-34 m; p < .001) and distance to maximal claudication pain by 65% (389+/-29 m to 641+/-34 m; p < .001). The increased distance to onset of pain was independently related to a 27% increase in calf blood flow (r = .42, p < .001) and to baseline age (r = -.26, p < .05), and the increased distance to maximal pain was predicted by a 10% increase in peak oxygen uptake (r = .41, p < .001) and by a 10% improvement in walking economy (r = -.34, p < .05). Free-living daily physical activity increased 31% (337+/-29 kcal/day to 443+/-37 kcal/day; p < .001) and was related to the increases in treadmill distances to onset (r = .24, p < .05) and to maximal pain (r = .45, p < .001). CONCLUSIONS: Increased claudication distances following exercise rehabilitation are mediated through improvements in peripheral circulation, walking economy, and cardiopulmonary function, with younger patients having the greatest absolute ambulatory gains. Furthermore, improved symptomatology translated into enhanced community-based ambulation.