Peripheral arterial disease and its clinical significance in nonagenarians

BACKGROUND AND AIMS: The purpose of this study was to characterize the prevalence and clinical features of peripheral arterial disease (PAD) among 90-year-old individuals and to assess its relationship to lower extremity functional status and survival over one year. METHODS: A prospective, population- based study of all 90-year-old residents of Jyv?skyl?, Finland. Fifty-eight out of the 79 registered residents were examined for ankle-brachial index (ABI). Lower extremity functional status was assessed as self-reported difficulty in performing specific physical activities of daily living (PADL). In a subgroup of 36 individuals, lower extremity functioning was further assessed by measuring walking endurance and walking velocity. Death dates were collected for one year after the examination from the hospital register. RESULTS: Thirteen persons (22%) had an ABI<0.9. PAD was asymptomatic in 11 of them and the diagnosis of PAD new to 12 of them. Thirty (52%) subjects had a normal ABI (0.9-1.4) and in 15 (26%) cases the ABI was pathologically high (>1.4). A significant accumulation of cardiovascular risk factors was observed among those with an ABI<0.9 compared with those with normal or high ABI (2.0+/-0.8 vs 1.3+/-0.8 vs 1.5+/-0.5, p=0.03). Those with low or high ABI reported more difficulties in the PADL tasks than those with normal ABI, but the results did not reach statistical significance. No difference in maximal walking velocity was observed according to ABI in the subgroup with data available. After one year, nine people had died, of whom only two (7%) with normal ABI and seven with low or high ABI (25%) (p=0.05). CONCLUSIONS: PAD was found to be mainly asymptomatic among 90-year-old people. An abnormal ABI was also associated with increased mortality risk over a one-year follow-up. Although our study was small-scale, it does provide novel information about the prevalence of PAD and clinical significance of ABI in very old people.     

Ethnic differences in peripheral arterial disease in the NHLBI Genetic Epidemiology Network of Arteriopathy (GENOA) study

Few studies have investigated whether ethnic groups differ in the prevalence of peripheral arterial disease (PAD). We compared the distribution of the ankle-brachial index (ABI), a measure of PAD, between African Americans and non-Hispanic white individuals. Subjects (n = 931) belonged to the Genetic Epidemiology Network of Arteriopathy (GENOA) study, a community-based study of hypertensive sibships, and included 453 African Americans from Jackson, Mississipi (mean age 72 +/- 6 years, 69% women) and 478 non-Hispanic white individuals from Rochester, Minnesota (mean age 58 +/- 7 years, 64% women). ABI was determined at two sites in each lower extremity and the lowest of four indices was used in the analyses. PAD was defined as an ABI of < or = 0.95. Information about conventional risk factors was derived from interviews and from blood samples drawn at the study visit. The prevalence of diabetes and hypertension was significantly higher in African Americans than in non-Hispanic white individuals. After adjusting for age, African American subjects had a lower mean ABI (women 0.97 vs 1.04, p < 0.001; men 0.96 vs 1.12, p < 0.001) and a greater prevalence of PAD (women 34% vs 22%, p = 0.010; men 33% vs 11%, p < 0.001) than their non-Hispanic white counterparts. In multiple regression analyses, African American ethnicity was a predictor of a lower ABI and the presence of PAD in each sex after adjusting for age and other conventional risk factors. In conclusion, the lower ABI and greater prevalence of PAD in African Americans than in non-Hispanic white individuals is not explained by differences in conventional risk factors. Identifying additional 'novel' risk factors that account for the ethnic differences in PAD is an important next step towards understanding why such differences exist and developing more effective strategies to reduce the burden of PAD.     

Ankle brachial index as a marker of atherosclerosis in Chinese patients with high cardiovascular risk.

To obtain reliable data on the epidemiology, co-morbidities and risk factor profile of peripheral arterial disease (PAD), we evaluated the clinical significance of the ankle brachial index (ABI) as an indicator of PAD in Chinese patients at high cardiovascular (CV) risk. ABI was measured in 5,646 Chinese patients at high CV risk, and PAD was defined as an ABI<0.9 in either leg. Multivariable logistic regression analyses were performed to identify factors associated with PAD. A total of 5,263 patients were analyzed, 52.9% male, mean age 67.3 years, mean body mass index (BMI) 24.2 kg/m2, mean systolic/diastolic blood pressure (SBP/DBP) 139/80.7 mmHg. The prevalence of PAD in the total group of patients was 25.4%, and the prevalence was higher in females than in males (27.1% vs. 23.9%; odds ratio [OR]: 1.64). Patients with PAD were older than those without PAD (72.3+/-9.9 years vs. 65.6+/-11.7 years; OR: 1.06), and more frequently had diabetes (43.3% vs. 31.3%; OR: 2.02), coronary heart disease (CHD) (27.0% vs. 18.8%; OR: 1.67), stroke (44.4% vs. 28.3%; OR: 1.78), lipid disorders (57.2% vs. 50.7%; OR: 1.3) and a smoking habit (42.7% vs. 38.6%; OR: 1.52). The ORs for the PAD group compared with the non-PAD group demonstrated that these conditions were inversely related to ABI. Statin, angiotensin-converting enzyme-inhibitors and antiplatelet agents were only used in 40.5%, 53.6% and 69.1% of PAD patients, respectively. The data demonstrated the high prevalence and low treatment of PAD in Chinese patients at high CV risk. A lower ABI was associated with generalized atherosclerosis. Based on these findings, ABI should be a routine measurement in high risk patients. Aggressive medication was required in these patients.     

Endothelial reactivity and cardiac risk factors in older patients with peripheral arterial disease

Peripheral arterial disease (PAD) is a major cause of morbidity and mortality. Endothelium-dependent vasoreactivity, which is advocated as a measure of vascular health, is impaired in persons with cardiac risk factors and coronary artery disease. Few studies have examined the degree of endothelial dysfunction in patients with PAD. Using high-resolution external vascular ultrasound, we measured brachial artery diameter and flow at rest, and in response to reactive hyperemia (flow-mediated dilation) in 50 older patients (age 69 +/- 1 year) with PAD (ankle-to-brachial artery index of 0.67 +/- 0.03), and 50 age-matched non-PAD patients. Coronary artery disease was more prevalent in PAD than in non-PAD patients (40% vs 4%, p <0.001). Systolic blood pressure (153 +/- 4 vs 141 +/- 3 mm Hg, p <0.01), fasting glucose (129 +/- 6 vs 109 +/- 5 mg/dl, p <0.001), and pack-years smoked (54 +/- 7 vs 25 +/- 3, p <0.01) were higher in the PAD than in non-PAD patients. There were no differences in baseline brachial artery diameter, blood velocity, or flow between the 2 groups. However, the 1-minute postocclusion percent change in diameter (6.5 +/- 0.7% vs 9.8 +/- 0.7%, p <0.001) and the change in diameter (0.22 +/- 0.02 vs 0.33 +/- 0.02 mm, p <0.001) were lower in PAD than in non-PAD patients, suggesting impaired endothelium-dependent dilation. The postocclusion hyperemic velocity and blood flow were also lower in PAD than in non-PAD patients. In multiple regression analyses the low-density lipoprotein-to-high-density lipoprotein cholesterol ratio, elevated fasting glucose, and high systolic blood pressure were independent predictors of percent change in brachial artery diameter (r2 = 0.37, p <0.001). Thus, older patients with PAD had impaired endothelial dependent vasodilation compared with controls that was associated with the presence of cardiac risk factors. The effect of cardiac risk factor intervention on endothelial function in patients with PAD remains to be determined.     

Effect of angiotensin blockade on the association between albuminuria and peripheral arterial disease in elderly Taiwanese patients with type 2 diabetes mellitus.

BACKGROUND: The aim of the present study was to examine the impact of the clinical use of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) on the association between the urinary albumin/creatinine ratio (ACR) and ankle-brachial index (ABI) or peripheral arterial disease (PAD) in elderly Taiwanese patients with type 2 diabetes mellitus. METHODS AND RESULTS: Two-hundred and ninety patients (108 men, 182 women) aged > or = 65 years (mean +/- SD, 71.6 +/-4.9) were cross-sectionally studied. ACR was expressed as the natural logarithm [ln(ACR)] and divided into normoalbuminuria (< 30.0 microg/mg) and albuminuria (> or = 30.0 microg/mg). ABI was evaluated both continuously and as peripheral arterial disease (PAD) (-) and PAD (+) using the cutoff of 0.9. Statistical analyses were performed with consideration of covariates and the use of ACEI/ARB. Results showed that in patients not using ACEI/ARB, ln (ACR) negatively correlated with ABI (r = -0.261, p < 0.01) and was associated with ABI with adjusted regression coefficient of -0.0213 (p < 0.05). PAD patients had a significantly higher level of ln (ACR) than those without PAD (4.83+/-1.34 vs 3.73+/-1.29, p < 0.001) and PAD prevalence was significantly higher in those with albuminuria than in those with normoalbuminuria (22.6% vs 4.9%, p < 0.001). The multivariate-adjusted odds ratio for PAD for every 1 unit increment of ln (ACR) was 2.10 (1.31-3.38), and for albuminuria vs normoalbuminuria 3.86 (1.04-14.31) in patients not using ACEI/ARB. In patients using ACEI/ARB, none of these analyses was significant. Patients using ACEI/ARB had a significantly lower risk of PAD with a multivariate-adjusted odds ratio of 0.34 (0.12-0.97). CONCLUSIONS: ACR negatively correlates with ABI and is associated with PAD in elderly diabetic patients not treated with ACEI/ARB. The use of ACEI/ARB attenuates this association and may be associated with a lower risk of PAD.     

Relation of levels of hemostatic factors and inflammatory markers to the ankle brachial index

Associations between hemostatic and inflammatory markers relative to the ankle brachial index (ABI), an indicator of the presence and severity of peripheral arterial disease (PAD), are not fully understood. We studied relations among selected hemostatic factors, inflammatory markers, and the ankle brachial index (ABI) in patients with and without peripheral arterial disease (PAD). Participants were 370 men and women with ABI <0.90 and 231 patients with ABI 0.90 to 1.50 identified from noninvasive vascular laboratories and general medicine practice. Blood factors were D-dimer, prothrombin 1.2, tissue plasminogen activator (t-PA) antigen, plasminogen activator inhibitor-1 (PAI-1), and inflammatory markers (high-sensitivity C-reactive protein [CRP], fibrinogen, and serum amyloid A [SAA]). Among patients without a history of cardiac or cerebrovascular disease, the ABI was significantly inversely associated with log D-dimer (p <0.001), log prothrombin 1.2 (p = 0.001), log CRP (p <0.001), and log fibrinogen (p = 0.005) in unadjusted analyses. In multivariable regression analyses adjusting for all blood factors as well as potential confounders, D-dimer was associated independently with ABI in participants with a history of cardiac or cerebrovascular disease (p = 0.003) and in participants without a history of cardiac or cerebrovascular disease (p = 0.017). In these analyses, CRP was associated independently with ABI among participants with a history of cardiac or cerebrovascular disease (p = 0.026). CRP was not associated independently with ABI in participants without a history of cardiac or cerebrovascular disease. We conclude that D-dimer levels may be more sensitive than other blood markers for measuring the extent of atherosclerosis in lower extremity arteries.     

Lower extremity ischemia, calf skeletal muscle characteristics, and functional impairment in peripheral arterial disease

OBJECTIVES: To determine whether lower ankle brachial index (ABI) levels are associated with lower calf skeletal muscle area and higher calf muscle percentage fat in persons with and without lower extremity peripheral arterial disease (PAD). DESIGN: Cross-sectional. SETTING: Three Chicago-area medical centers. PARTICIPANTS: Four hundred thirty-nine persons with PAD (ABI<0.90) and 265 without PAD (ABI 0.90-1.30). MEASUREMENTS: Calf muscle cross-sectional area and the percentage of fat in calf muscle were measured using computed tomography at 66.7% of the distance between the distal and proximal tibia. Physical activity was measured using an accelerometer. Functional measures included the 6-minute walk, 4-meter walking speed, and the Short Physical Performance Battery (SPPB). RESULTS: Adjusting for age, sex, race, comorbidities, and other potential confounders, lower ABI values were associated with lower calf muscle area (ABI<0.50, 5,193 mm(2); ABI 0.50-0.90, 5,536 mm(2); ABI 0.91-1.30, 5,941 mm(2); P for trend<.001). These significant associations remained after additional adjustment for physical activity. In participants with PAD, lower calf muscle area in the leg with higher ABI was associated with significantly poorer performance in usual- and fast-paced 4-meter walking speed and on the SPPB, adjusting for ABI, physical activity, percentage fat in calf muscle, muscle area in the leg with lower ABI, and other confounders (P<.05 for all comparisons). CONCLUSION: These data support the hypothesis that lower extremity ischemia has a direct adverse effect on calf skeletal muscle area. This association may mediate previously established relationships between PAD and functional impairment.     

Measures of arterial stiffness and wave reflection are associated with walking distance in patients with peripheral arterial disease

We hypothesized that measures of arterial stiffness and wave reflection influence functional capacity of patients with peripheral arterial disease (PAD). Consecutive patients (n=106, 69+/-10 years, 66% men) referred for lower extremity arterial evaluation were studied. Radial artery pulse waveforms were obtained by applanation tonometry and an ascending aortic pressure waveform derived by a transfer function. Aortic augmentation index (AIx) is the difference between the first and second systolic peak of the ascending aortic pressure waveform indexed to the pulse pressure (PP) and T(r) is the reflected wave arrival time. Ankle-brachial index (ABI) and walking distance were measured as per laboratory protocol after excluding patients with non-compressible vessels (ABI>1.5) and severe PAD (ABI<0.5). To account for right-censoring of walking distances in patients completing the 5 min walk (n=56), we used survival analysis to identify variables associated with walking distance. Mean (+/-S.D.) values were: AIx, 31.2+/-10.9%; T(r), 134+/-18 ms; PP, 66.5+/-17.1 mmHg; ABI, 0.87+/-0.22; walking distance, 177+/-75 m. In both multivariable accelerated failure time (AFT) and Cox proportional-hazards models, older age, female sex, greater body mass index, lower ABI, and a measure of arterial stiffness (higher AIx and PP, lower T(r)) were associated with a lower walking distance. Higher AIx and lower T(r) were associated with a lower walking distance even after adjustment for PP as well as in the subset of patients with PAD (ABI<0.9 at rest or post-exercise, n=82). In conclusion, measures of arterial stiffness and wave reflection are associated with walking distance in patients with PAD and may be a target of therapy in such patients.     

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.     

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.     

Acute reduction in ankle/brachial index following smoking in chronic smokers with peripheral arterial occlusive disease.

The ankle-brachial systolic pressure index (ABI), a noninvasive measure of peripheral arterial occlusive disease (PAOD) severity, is considered a marker of atherosclerosis and an independent predictor of mortality. However, it is not known whether factors other than PAOD severity, such as cigarette smoking, have an effect on ABI measurement. Therefore, the authors examined the acute effects of cigarette smoking on ABI and the peripheral circulation in 10 older (63 +/- 10 years) chronic smokers (39 +/- 37 pack-years) with PAOD (ABI=0.64 +/- 0.14). The patients were instructed to refrain from smoking and from consuming caffeine-containing beverages for at least 12 hours before the tests. The patients were randomly assigned to 2 days of testing consisting of a nonsmoking and a smoking day. Resting heart rate, blood pressure, ABI, and calf blood flow by plethysmography were obtained on both testing days. The smoking day consisted of smoking two filter cigarettes over a period of 10 minutes before the measurement of ABI and calf blood flow. The ABI on the smoking day (0.55 +/- 0.11) was lower (p=0.008) than on the nonsmoking day (0.64 +/- 0.14) owing to a lower (p=0.020) ankle systolic blood pressure (81 +/- 28 vs 93 +/- 28 mmHg). Brachial systolic blood pressures, heart rate, and calf blood flow were not altered by smoking (p>0.05). These results demonstrate that the acute effect of cigarette smoking lowers the ABI in chronic smokers with intermittent claudication, thereby yielding evidence of a transient deleterious effect of cigarette smoking on the peripheral circulation in chronic smokers.     

The effect of current cigarette smoking on calf muscle hemoglobin oxygen saturation in patients with intermittent claudication

The purpose of this study was to compare calf muscle hemoglobin oxygen saturation response during exercise between smokers and non-smokers with peripheral arterial disease. Patients limited by intermittent claudication who were smokers (n = 12) were compared with those who had not smoked (n = 28) for at least 1 year prior to investigation. Ankle/brachial index (ABI) measurements were obtained with Doppler ultrasound, and maximal calf blood flow was measured by venous occlusion plethysmography. Hemoglobin oxygen saturation (StO2) of the calf muscle, initial claudication distance (ICD), and absolute claudication distance (ACD) were obtained during a graded treadmill test. Smokers refrained from smoking on the morning of the test. Smokers had similar ABI values compared with non-smokers (0.70 +/- 0.26 vs 0.73 +/- 0.23 [mean +/- SD]; p = 0.808), whereas the smokers had lower values for maximal calf blood flow (8.71 +/- 5.76 %/min vs 11.48 +/- 4.46 %/min; p = 0.038), ICD (122 +/- 123 m vs 243 +/- 177 m; p = 0.023), and ACD (284 +/- 170 m vs 452 +/- 263 m; p = 0.023). Additionally, smokers had lower calf muscle StO2 values at the end of 1 minute (16 +/- 15% vs 37 +/- 19%; p = 0.002) and 2 minutes of exercise (16 +/- 16% vs 35 +/- 25%; p = 0.008), and at the occurrence of ICD (17 +/- 17% vs 32 +/- 23%; p = 0.033) and ACD (16 +/- 16% vs 32 +/- 24%; p = 0.024). After adjusting for blood flow, calf muscle StO2 values remained lower in the smokers (p < 0.05). Finally, calf muscle StO2 at the end of the first minute of exercise was related to ICD (r = 0.611, p < 0.001) and ACD (r = 0.443, p < 0.01). In conclusion, smokers limited by intermittent claudication have lower calf muscle StO2 during exercise than nonsmokers, and lower StO2 during exercise is associated with shorter ICD and ACD.     

Association of low ankle brachial index with high mortality in primary care.

AIMS: We aimed to assess the increased risk of death and severe vascular events in elderly individuals with subclinical or manifest peripheral arterial disease (PAD), evidenced by low ankle brachial index (ABI < 0.9) in primary care. METHODS AND RESULTS: In this monitored prospective observational study, 6880 representative unselected patients aged >or=65 years were followed up over 3 years by 344 primary care physicians. Main outcome measures were mortality or a combined endpoint of mortality and severe vascular events. In total, 20 127 patient-years were observed. In the group of PAD patients (n=1230), 134 patients died; in the group without PAD (n=5591), 237 patients died [multivariate hazard ratio (HR) 2.0; 95% confidence interval 1.6-2.5, P<0.001]. Compared with an ABI>or=1.1, the risk of death increased linearly in the lower ABI categories: ABI 0.7-0.89, HR 1.7 (1.2-2.4, P<0.001); ABI<0.5, HR 3.6 (2.4-5.4, P<0.001). CONCLUSION: Patients with a low ABI (PAD), who can be readily identified in a primary care setting, have a substantially increased risk of death and severe vascular events. Patients with an ABI between 1.1 and 0.9 should be considered and followed up as borderline PAD cases. Particular attention should be paid to patients with PAD and previous vascular events, as their risk is markedly increased.     

Comparison of usefulness of inflammatory markers in patients with versus without peripheral arterial disease in predicting adverse cardiovascular outcomes (myocardial infarction, stroke, and death)

We tested the hypothesis that a combination of measurements of different aspects of atherosclerosis, including burden of atherosclerosis and levels of inflammation, would contain more predictive information than either alone in an outpatient population. We enrolled 110 patients (62 +/- 15 years of age) who were referred to the noninvasive vascular laboratory for sequential Doppler pressure measurements of the lower extremities. We measured ankle-brachial index (ABI) and serum markers of inflammation and followed subjects for a mean of 2.25 years. Fifty subjects did not have peripheral arterial disease (PAD; ABI > or =0.9), whereas 60 did (ABI <0.9). Markers of inflammation, including C-reactive protein (3.83 +/- 0.9 vs 2.11 +/- 1.1, p = 0.019), were higher in subjects who had PAD. During follow-up, 42% developed an event (myocardial infarction, stroke, unplanned coronary or lower extremity revascularization, or death). Decreasing ABI (chi-square 7.3, p = 0.026) and increasing C-reactive protein (chi-square 22.1, p <0.001) increased the risk of an event. Risk increased sixfold between the lowest and highest groups for all events and fourfold for hard events (myocardial infarction, stroke, and death) using both C-reactive protein and ABI. In conclusion, patients who have PAD and increased inflammation are at highest risk for adverse cardiovascular outcomes. Characterizing atherosclerosis on the basis of these parameters provides important prognostic information.     

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.     

Low serum testosterone and high serum estradiol associate with lower extremity peripheral arterial disease in elderly men. The MrOS Study in Sweden.

OBJECTIVES: This study sought to determine whether serum levels of testosterone and estradiol associate with lower extremity peripheral arterial disease (PAD) in a large population-based cohort of elderly men. BACKGROUND: Few studies have explored the relationship between serum sex steroids and lower extremity PAD in men. METHODS: The Swedish arm of the MrOS (Osteoporotic Fractures in Men) study (n = 3,014; average age 75.4 years) assessed ankle-brachial index (ABI) and defined lower extremity PAD as ABI <0.90. Radioimmunoassay measured serum levels of total testosterone, estradiol, and sex hormone-binding globulin, and we calculated free testosterone and free estradiol levels from the mass action equations. RESULTS: A linear regression model including age, current smoking, previous smoking, diabetes, hypertension, body mass index, free testosterone, and free estradiol showed that free testosterone independently and positively associates with ABI (p < 0.001), whereas free estradiol independently and negatively associates with ABI (p < 0.001). Logistic regression analyses showed that free testosterone in the lowest quartile (vs. quartiles 2 to 4; odds ratio [OR] 1.65, 95% confidence interval [CI] 1.22 to 2.23, p = 0.001) and free estradiol in the highest quartile (vs. quartiles 1 to 3; OR 1.45, 95% CI 1.09 to 1.94, p = 0.012) independently associate with lower extremity PAD. CONCLUSIONS: This cross-sectional study shows for the first time that low serum testosterone and high serum estradiol levels associate with lower extremity PAD in elderly men. Future prospective and interventional studies are needed to establish possible causal relationships between sex steroids and the development of lower extremity PAD in men.     

Symptoms of chronic arterial insufficiency correlate with absolute ankle pressure better than with ankle: brachial index

BACKGROUND: Doppler-based measurement of the ankle: brachial index (ABI) has long been regarded as the standard by which to objectively quantify the degree of lower extremity arterial occlusive disease, but this method fails to account for the contribution of systemic blood pressure to actual limb perfusion. We hypothesized that the absolute blood pressure would be a better predictor of the severity of symptoms of chronic occlusive disease than the ABI. Experimental design: retrospective comparative study. Setting: university inpatient/outpatient vascular laboratory. Patients: 1396 evaluable patients out of 2436 total consecutive patients referred with suspected lower extremity arterial occlusive disease. Measures: comparison of absolute ankle and digital pressures and ABI according to severity of symptoms of chronic lower extremity ischemia using three-way analysis of variance (ANOVA), likelihood ratios, and receiver operator characteristic (ROC) curves. RESULTS: The symptoms of tissue ulcer/gangrene, rest pain, and gangrene were characterized by differences in absolute pressures in the great toe (47 +/- 42 mmHg vs 55 +/- 40 mmHg vs 62 +/- 33 mmHg [mean +/- SD], F = 19.05, p < 0.001) and ankle (92 +/- 53 mmHg vs 98 +/- 44 mmHg vs 106 +/- 37 mmHg, F = 12.91, p < 0.001), but not by the ABI (0.71 +/- 0.33 vs 0.68 +/- 0.34 vs 0.71 +/- 0.28, F = 1.24, p > 0.05). ROC curves confirmed absolute digital pressure (area under curve [AUC] = 0.628) and absolute ankle pressure (AUC = 0.607) to be superior to ABI (AUC = 0.572). CONCLUSIONS: The severity of symptoms for peripheral vascular disease correlate better with absolute pressure measurement than with ABI.     

Relationship between free-living daily physical activity and peripheral circulation in patients with intermittent claudication

The purpose of this study was to determine the relationship between free-living daily physical activity and peripheral circulation under resting, reactive hyperemia, and maximal exercise conditions in peripheral arterial occlusive disease (PAOD) patients with intermittent claudication. Sixty-one PAOD patients (age = 70 +/- 6 years, ankle/brachial index [ABI] = 0.57 +/- 0.24) were recruited from the Vascular Clinic at the Baltimore Veterans Affairs Medical Center and from radio and newspaper advertisements. Free-living daily physical activity was measured as the energy expenditure of physical activity (EEPA), determined from doubly labeled water and indirect calorimetry. Patients also were characterized on ankle/brachial index, calf blood flow, calf transcutaneous oxygen tension (TcPO2), and calf transcutaneous heating power (TcHP). ABI and calf blood flow served as markers of the macrocirculation of the lower extremity, while TcPO2 and TcHP served as markers of the microcirculation. The claudication patients were sedentary, reflected by a mean EEPA value of 486 +/- 274 kcal/day. EEPA was related to calf TcHP at rest (282 +/- 24 mW; r = -0.413, p = 0.002), after postocclusion reactive hyperemia (275 +/- 22 mW; r = -0.381, p = 0.004), and after maximal exercise (276 +/- 20 mW; r = -0.461, p<0.001). ABI, calf blood flow, and calf TcPO2 were not related to EEPA under any condition. In conclusion, higher levels of free-living daily physical activity were associated with better microcirculation of the calf musculature in older PAOD patients with intermittent claudication.     

Validation of a new method of detecting peripheral artery disease by determination of ankle-brachial index using an automatic blood pressure device

Peripheral artery disease (PAD) is a predictor of total and cardiovascular mortality; its most valuable simple index is the ankle-brachial index (ABI). The present study was designed to assess whether a commercially available automatic device could be used to determine ABI in comparison with the classical Doppler method. The ABI was defined as the ratio of systolic blood pressure at each ankle to the maximal brachial systolic pressure, a pathological index being defined for a ratio <0.90. The ABI were calculated in 219 consecutive patients (aged 55 +/-19 years) with systolic blood pressure measured either by using a mercury sphygmo-manometer and a continuous-wave Doppler probe or an automatic manometer Omron M4. This device has been validated for measurements in upper limbs, and so the authors undertook validation in the lower limbs versus intraarterial measurements. There was an excellent correlation between intraarterial measurements and automatic readings in the range of 70-220 mm Hg, r=0.99, p<0.001. The systolic pressures measured in upper limbs correlated well in the right (r=0.87, p<0.001) and the left (r=0.89, p<0.001) upper limbs; and in the left (r=0.72, p<0.001) and the right (r=0.68, p<0.001) lower limbs. Correlations between ABI in both methods were good in the left (r=0.66, p<0.001) and the right (r=0.61, p<0.001) lower limbs. The sensitivity (76%), specificity (95%), positive predictive value (86%), negative predictive value (90%), and global accuracy (89%) of a pathological automatic index to predict an abnormal Doppler index were good. The use of a simple, automatic blood pressure device to determine ABI appears feasible, easy, and precise. It would provide a practical tool for physicians not trained in Doppler to detect PAD.     

Non-invasive vascular assessment in people with type 2 diabetes: Diagnostic performance of Plethysmographic-and-Doppler derived ankle brachial index,toe brachial index,and pulse volume wave analysis for detection of peripheral arterial disease

ObjectiveThere is evidence that standard assessment techniques for detecting PAD might be of less diagnostic accuracy in people with type 2 diabetes. The aim of this study was to examine diagnostic performance of Plethysmographic-and-Doppler derived ankle brachial index, toe brachial index, and Pulse volume waveform analysis for detecting PAD in people with T2DM.MethodsIn this cross-sectional study 303 patients with T2DM were included in the study. The participants underwent ABI measurement, applying both Plethysmographic and Doppler derived devices, as well as TBI, PVW was also recorded for each patient. Diagnostic performance of each test for detecting PAD, applying ultrasound Doppler scan as the reference standard, was measured. Moreover, the best cut-off point for each method to detect PAD was determined.ResultsPVW showed the highest sensitivity (81.8%) for detecting PAD, followed by ABI_DOP (72.7%), and ABI_PLE (20%). However, all devices showed an excellent specificity for detecting PAD. The optimal cut-off point for diagnosis of PAD was 0.9 for ABI_DOP, 1.2 for ABI_PLE, and 0.38 for TBI.ConclusionWithin this population of patients with T2DM, TBI less than 0.38 provided the best sensitivity for detection of PAD followed by PVW, ABI_DOP ≤ 0.9, and ABI_PLE < 1.2.