The correlation between symptoms and non-invasive test results in patients referred for peripheral arterial disease testing

A normal penile pressure cannot rule out the presence of lesions on the arteries supplying the hypogastric circulation in patients with arterial claudication

Abstract

Proximal claudication remains a difficult diagnosis. The ankle to brachial index may be insensitive in the case of isolated hypogastric lesions. Penile pressure represents an alternative method for proximal arteries. Surprisingly, the accuracy of penile pressure measurement in detecting lesions on the arteries supplying pelvic circulation in patients suffering claudication has rarely been studied. We aimed to evaluate the diagnostic accuracy of the penile brachial index < 0.60 (penile over brachial systolic pressure ratio) to non-invasively investigate arteriographic lesions on arteries supplying the hypogastric circulation in 88 male patients referred for Fontaine stage II. The receiver operating characteristic (ROC) curve was used to define the diagnostic performance of the penile brachial index and search for a specific cut-off point in this population. Accuracy was 69.3% (95% confidence interval: 58.6–78.7) for the detection of an arterial stenosis or occlusion on at least one side. The penile brachial index ≤ 0.45 was 74% sensitive and 68% specific to discriminate the 19 patients with bilateral arterial occlusion from the other 66 patients. In conclusion, the penile brachial index is relatively insensitive for the detection of proximal abnormal blood flow impairment except in the case of bilateral occlusion of arteries supplying the hypogastric circulation in patients with claudication. A normal penile pressure is probably not efficient enough to rule out the presence of lesions on the arteries towards the hypogastric circulation in patients with arterial claudication.

Efficacy of arm-ergometry versus treadmill exercise training to improve walking distance in patients with claudication

Abstract

The efficacy of treadmill walking training to improve pain-free (PFWD) and maximal (MWD) walking distance in patients with claudication is well documented. The effects of aerobic arm-ergometry to improve PFWD and MWD compared to treadmill walking or usual care are not known. Forty-one participants (29 male, 12 female, mean age 67.7 years, 92.7% smoking history, 36.6% with diabetes) with lifestyle-limiting claudication were randomized to 12 weeks of 3 hours/week of supervised exercise training using either arm-ergometry, treadmill walking, or a combination, versus control. PFWD and MWD were assessed before and after training, and after 12 weeks of follow-up. The 12-week MWD increased significantly in the arm-ergometry (+53%), treadmill (+69%), and combination (+68%) groups ( p < 0.002 versus control). The 24-week MWD was maintained in the arm-ergometry ( p = 0.009) and treadmill ( p = 0.019) groups, whereas the combination group declined ( p = 0.751) versus control. The 12-week PFWD increased significantly in the arm-ergometry group (+82%; p = 0.025 versus control). Change in PFWD in treadmill (+54%; p = 0.196 versus control) and combination (+60%; p = 0.107 versus control) groups did not reach statistical significance. PFWD improvement was maintained in the arm-ergometry group after a 12-week follow-up (+123%; p = 0.011 versus control). In conclusion, these pilot data demonstrate for the first time that dynamic arm exercise training can improve walking capability in people with peripheral arterial disease (PAD)-induced claudication compared to participants receiving usual care and that improvement was not different from that seen with treadmill walking exercise training. Dynamic arm exercise may be a therapeutic exercise option for patients with PAD.

Prevalência e fatores de risco da doença arterial periférica sintomática e assintomática em hospital terciário, Rio de Janeiro, Brasil

CONTEXTO: Doença arterial periférica é caracterizada pelo índice tornozelo-braquial (ITB) < 0,90, em indivíduos ≥ 40 anos, aumentando a prevalência com a idade. OBJETIVO: Detectar a prevalência de doença arterial periférica assintomática e sintomática, com introdução do ITB, associada a fatores de risco demarcados. MÉTODOS: Coorte descritiva identificada em unidade hospitalar terciária de angiologia, de dezembro de 2006 a dezembro de 2007, com idade ≥ 30 anos. Doenças pregressas e fatores de risco foram analisados associados à prevalência. ITB < 0,90 e questionário padronizado definiram doença arterial periférica sintomática com claudicação e assintomática com ausência de claudicação, ambas comparadas aos sem doença arterial periférica (ITB 0,90-1,30). A análise estatística utilizou programa SPSS, com significância de p < 0,05. RESULTADOS: Dos 407 pacientes, 248 apresentaram doença arterial periférica, sendo 52,2% do sexo feminino, com média de idade de 70,1±10,2 anos (p < 0,005). A prevalência de 60,9% (IC95% 56-66) foi subdividida em: assintomática, 10,1% (IC95% 6,3-13,8); e sintomática, 89,9% (IC95% 86,2-93,7). Destes, 32,2% (IC95% 26,4-38,1) apresentaram isquemia crítica. Ajustada por sexo e idade, a prevalência aumenta significativamente entre 55-74 anos, com predomínio do feminino (1,35:1) nos indivíduos acima de 74 anos. A prevalência dos assintomáticos e sintomáticos foi influenciada por tabagismo, hipertensão, diabéticos autorreferidos e confirmados, sobrepeso, infarto agudo do miocárdio e acidente vascular encefálico (p < 0,005). A média do ITB foi mais baixa nos sintomáticos (0,57±0,17) (p < 0,005). CONCLUSÃO: O ITB detectou doença arterial periférica com graus variáveis de gravidade associada a fatores de risco, identificando os assintomáticos não-claudicantes e os sintomáticos em unidade terciária.

Management of lower extremity peripheral arterial disease

Peripheral arterial disease (PAD), a manifestation of systemic atherosclerosis, is a significant health problem. It manifests in lower extremities as intermittent claudication, limb ischemia, or gangrene and other locations as stroke, renal failure, or mesenteric ischemia. Fontaine and Rutherford classifications are the 2 commonly used classifications to stage the severity of PAD. The diagnostic tools include ankle-brachial index, a valuable tool in diagnosing lower extremity PAD, and a treadmill test. Other useful diagnostic tools include the San Diego Claudication Questionnaire to screen patients for symptoms and imaging modalities such as duplex scan, angiogram, computer tomographic angiogram, and magnetic resonance angiogram. Medical management of PAD involves comprehensive care, including risk factor modification of etiologies predisposing to atherosclerosis. These involve using antiplatelet therapy with aspirin or clopidogrel, controlling hypertension, managing hypercholesterolemia, and using vasodilators such as cilostazol. Exercise rehabilitation is an efficacious approach to improve intermittent claudication and should be recommended to each patient. Revascularization therapy is indicated for those who have critical limb ischemia or severe claudication not improved by medical management. Revascularization consists of endovascular techniques to open up the vessel and traditional bypass surgery to bypass the diseased segment. Recent published guidelines detailing recommendations on different treatment modalities in patients with PAD are described.

Physical activity during daily life and functional decline in peripheral arterial disease

BACKGROUND

Few modifiable behaviors have been identified that are associated with slower rates of functional decline in persons with lower-extremity peripheral arterial disease. We determined whether higher levels of physical activity during daily life are associated with less functional decline in persons with peripheral arterial disease.

METHODS AND RESULTS

The study population included 203 peripheral arterial disease participants who underwent vertical accelerometer-measured physical activity continuously over 7 days and were followed up annually for up to 4 years (mean, 33.6 months). Outcomes were average annual changes in 6-minute walk performance, usual-paced and fast-paced 4-m walking velocity, and the short performance physical battery. Analyses were adjusted for age, sex, race, comorbidities, body mass index, ankle brachial index, smoking, and walking exercise frequency. Higher baseline physical activity levels measured by a vertical accelerometer were associated with significantly less average annual decline in 6-minute walk performance (P for trend=0.010), fast-paced 4-m walking velocity (P for trend=0.002), and the short performance physical battery (P for trend=0.001). Compared with the lowest baseline quartile, those in the highest baseline quartile of physical activity had less annual decline in 6-minute walk performance (-50.82 versus -107.0 ft/y; P=0.019), fast-paced 4-m walking speed (-0.0034 versus -0.111 m . s(-1) . y(-1); P=0.002), and the short performance physical battery (-0.074 versus -0.829; P=0.005).

CONCLUSIONS

Higher physical activity levels during daily life are associated with less functional decline among people with peripheral arterial disease. These findings may be particularly important for the large number of peripheral arterial disease persons without access to supervised walking exercise programs.

Treadmill exercise and resistance training in patients with peripheral arterial disease with and without intermittent claudication: a randomized controlled trial

CONTEXT

Neither supervised treadmill exercise nor strength training for patients with peripheral arterial disease (PAD) without intermittent claudication have been established as beneficial.

OBJECTIVE

To determine whether supervised treadmill exercise or lower extremity resistance training improve functional performance of patients with PAD with or without claudication.

DESIGN, SETTING, AND PARTICIPANTS

Randomized controlled clinical trial performed at an urban academic medical center between April 1, 2004, and August 8, 2008, involving 156 patients with PAD who were randomly assigned to supervised treadmill exercise, to lower extremity resistance training, or to a control group.

MAIN OUTCOME MEASURES

Six-minute walk performance and the short physical performance battery. Secondary outcomes were brachial artery flow-mediated dilation, treadmill walking performance, the Walking Impairment Questionnaire, and the 36-Item Short Form Health Survey physical functioning (SF-36 PF) score.

RESULTS

For the 6-minute walk, those in the supervised treadmill exercise group increased their distance walked by 35.9 m (95% confidence interval [CI], 15.3-56.5 m; P < .001) compared with the control group, whereas those in the resistance training group increased their distance walked by 12.4 m (95% CI, -8.42 to 33.3 m; P = .24) compared with the control group. Neither exercise group improved its short physical performance battery scores. For brachial artery flow-mediated dilation, those in the treadmill group had a mean improvement of 1.53% (95% CI, 0.35%-2.70%; P = .02) compared with the control group. The treadmill group had greater increases in maximal treadmill walking time (3.44 minutes; 95% CI, 2.05-4.84 minutes; P < .001); walking impairment distance score (10.7; 95% CI, 1.56-19.9; P = .02); and SF-36 PF score (7.5; 95% CI, 0.00-15.0; P = .02) than the control group. The resistance training group had greater increases in maximal treadmill walking time (1.90 minutes; 95% CI, 0.49-3.31 minutes; P = .009); walking impairment scores for distance (6.92; 95% CI, 1.07-12.8; P = .02) and stair climbing (10.4; 95% CI, 0.00-20.8; P = .03); and SF-36 PF score (7.5; 95% CI, 0.0-15.0; P = .04) than the control group.

CONCLUSIONS

Supervised treadmill training improved 6-minute walk performance, treadmill walking performance, brachial artery flow-mediated dilation, and quality of life but did not improve the short physical performance battery scores of PAD participants with and without intermittent claudication. Lower extremity resistance training improved functional performance measured by treadmill walking, quality of life, and stair climbing ability.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00106327.

Progression of peripheral arterial disease predicts cardiovascular disease morbidity and mortality

OBJECTIVES

The purpose of this study was to examine the association of progressive versus stable peripheral arterial disease (PAD) with the risk of future cardiovascular disease (CVD) events.

BACKGROUND

An independent association between PAD, defined by low values of the ankle-brachial index (ABI), and future CVD risk has been demonstrated. However, the prognostic significance of declining versus stable ABI has not been studied.

METHODS

We recruited 508 subjects (59 women, 449 men) from 2 hospital vascular laboratories in San Diego, California. ABI and CVD risk factors were measured at Visit 2 (1990 to 1994). ABI values from each subject's earliest vascular laboratory examination (Visit 1) were abstracted from medical records. Mortality and morbidity were tracked for 6 years after Visit 2 using vital statistics and hospitalization data.

RESULTS

In multivariate models adjusted for CVD risk factors, very low (<0.70) and, in some cases, low (0.70 < or = ABI <0.90) Visit 2 ABIs were associated with significantly elevated all-cause mortality, CVD mortality, and combined CVD morbidity/mortality at 3 and 6 years. Decreases in ABI of more than 0.15 between Visit 1 and Visit 2 were significantly associated with an increased risk of all-cause mortality (risk ratio [RR]: 2.4) and CVD mortality (RR: 2.8) at 3 years, and CVD morbidity/mortality (RR: 1.9) at 6 years, independent of Visit 2 ABI and other risk factors.

CONCLUSIONS

Progressive PAD (ABI decline >0.15) was significantly and independently associated with increased CVD risk. Patients with decreasing ABI may be candidates for more intensive cardiovascular risk factor management.

Comparison of atherosclerotic indicators between cardio ankle vascular index and brachial ankle pulse wave velocity

BACKGROUND

Aortic pulse wave velocity has been used for evaluating atherosclerosis. Recently, the development of the volume plethysmographic method has made it possible to easily measure the index of the pulse wave velocity. The brachial ankle pulse wave velocity and cardio ankle vascular index are used for estimating the extent of atherosclerosis. The diagnostic usefulness of these indexes in predicting coronary artery disease was examined.

METHODS

The brachial ankle pulse wave velocity, the cardio ankle vascular index, and the high-sensitivity C-reactive protein were measured in 696 patients who had chest pain and underwent coronary angiography. Measurement values of brachial ankle pulse wave velocity were compared with those of cardio ankle vascular index in terms of the baseline covariates and the number of major coronary vessels involved (vessel disease).

RESULTS

The brachial ankle pulse wave velocity was significantly correlated with age, systolic blood pressure, and diastolic blood pressure but not with the high-sensitivity C-reactive protein. The cardio ankle vascular index was correlated only with age and the high-sensitivity C-reactive protein. The average of both brachial ankle pulse wave velocity and cardio ankle vascular index values was greater in 3 vessel disease group than in 0 vessel disease group. The receiver operating characteristic curve showed that the diagnostic accuracy of coronary artery disease was significantly higher in the cardio ankle vascular index than in the brachial ankle pulse wave velocity (area under the curve +/- standard error: 0.691 +/- 0.025 vs. 0.584 +/- 0.026; P < .05).

CONCLUSIONS

As a means of estimating the extent of atherosclerosis in large arteries, our results show that both brachial ankle pulse wave velocity and cardio ankle vascular index are useful and that cardio ankle vascular index may have some advantages in its application to patients taking blood pressure-lowering medication because of the minimum effect of blood pressure on its measurement values. The cardio ankle vascular index has increased performance over brachial ankle pulse wave velocity in predicting the coronary artery disease.

Physical activity during daily life and circulating biomarker levels in patients with peripheral arterial disease

Higher levels of inflammation are associated with adverse outcomes in patients with lower extremity peripheral arterial disease (PAD). This study evaluated associations of physical activity during daily life with levels of inflammatory biomarkers, D-dimer, and homocysteine in patients with PAD. Participants were 244 men and women (mean age 74.4 +/- 8.2 years) with PAD (ankle brachial index <0.90). C-reactive protein, interleukin-6, soluble intracellular adhesion molecule-1, soluble vascular cellular adhesion molecule-1, D-dimer, and homocysteine were assessed at study entry. Physical activity was objectively assessed with a vertical accelerometer, which participants wore continuously for 7 days. After adjusting for age, gender, race, body mass index, smoking, co-morbidities, ankle brachial index, and other potential confounders, higher physical activity levels were associated linearly and significantly with lower levels of all measured circulating biomarkers: soluble vascular cellular adhesion molecule-1 (p trend = 0.001), D-dimer (p trend = 0.005), homocysteine (p trend = 0.006), interleukin-6 (p trend = 0.010), C-reactive protein (p trend = 0.028), and soluble intracellular adhesion molecule-1 (p trend = 0.033). In conclusion, higher levels of physical activity were associated independently with lower levels of inflammatory markers, homocysteine, and D-dimer in patients with PAD.

Diabetes-related microvascular and macrovascular diseases in the physical therapy setting

Physical therapists commonly treat people with diabetes for a wide variety of diabetes-associated impairments, including those from diabetes-related vascular disease. Diabetes is associated with both microvascular and macrovascular diseases affecting several organs, including muscle, skin, heart, brain, and kidneys. A common etiology links the different types of diabetes-associated vascular disease. Common risk factors for vascular disease in people with diabetes, specifically type 2 diabetes, include hyperglycemia, insulin resistance, dyslipidemia, hypertension, tobacco use, and obesity. Mechanisms for vascular disease in diabetes include the pathologic effects of advanced glycation end product accumulation, impaired vasodilatory response attributable to nitric oxide inhibition, smooth muscle cell dysfunction, overproduction of endothelial growth factors, chronic inflammation, hemodynamic dysregulation, impaired fibrinolytic ability, and enhanced platelet aggregation. It is becoming increasingly important for physical therapists to be aware of diabetes-related vascular complications as more patients present with insulin resistance and diabetes. The opportunities for effective physical therapy interventions (such as exercise) are significant.

Corridor-based functional performance measures correlate better with physical activity during daily life than treadmill measures in persons with peripheral arterial disease

OBJECTIVE

To compare associations of physical activity during daily life with treadmill walking performance and corridor-based functional performance measures in persons with lower extremity peripheral arterial disease (PAD).

STUDY DESIGN

Cross-sectional.

SUBJECTS

One hundred fifty-six men and women with PAD who completed baseline measurements and were randomized into the study to improve leg circulation (SILC) exercise clinical trial.

MAIN OUTCOME MEASURES

Participants completed a Gardner-Skinner treadmill protocol. Corridor-based functional performance measures were the 6-minute walk, walking velocity over four meters at usual and fastest pace, and the short physical performance battery (SPPB) (0-12 scale, 12 = best). Physical activity during daily life was measured continuously over 7 days with a Caltrac (Muscle Dynamics Fitness Network, Inc, Torrence, Calif) accelerometer.

RESULTS

Adjusting for age, gender, and race, higher levels of physical activity during daily life were associated with greater distance achieved in the 6-minute walk (P trend = .001), faster fast-paced four-meter walking velocity (P trend < .001), faster usual-paced four-meter walking speed (P trend = .027) and a higher SPPB (P trend = .005). The association of physical activity level with maximum treadmill walking distance did not reach statistical significance (P trend = .083). There were no associations of physical activity with treadmill distance to onset of leg symptoms (P trend = .795).

CONCLUSION

Functional performance measures are more strongly associated with physical activity levels during daily life than treadmill walking measures.

Association between daily ambulatory activity patterns and exercise performance in patients with intermittent claudication

PURPOSE

To determine the association between daily ambulatory activity patterns and exercise performance in patients with intermittent claudication.

METHODS

One hundred thirty-three patients limited by intermittent claudication participated in this study. Patients were assessed on their ambulatory activity patterns for 1 week with a small, lightweight step activity monitor attached to the ankle using elastic velcro straps above the lateral malleolus of the right leg. The step activity monitor recorded the number of strides taken on a minute-to-minute basis and the time spent ambulating. Patients also were characterized on ankle-brachial index (ABI), ischemic window (IW) after a treadmill test, as well as initial claudication distance (ICD), and absolute claudication distance (ACD) during treadmill exercise.

RESULTS

The patient characteristics (mean +/- SD) were as follows: ABI = 0.71 +/- 0.23, IW = 0.54 +/- 0.72 mm Hg.min.meter(-1), ICD = 236 +/- 198 meters, and ACD = 424 +/- 285 meters. The patients took 3366 +/- 1694 strides/day, and were active for 272 +/- 103 min/day. The cadence for the 30 highest, consecutive minutes of each day (15.1 +/- 7.2 strides/min) was correlated with ICD (r = 0.316, P < .001) and ACD (r = 0.471, P < 0.001), and the cadence for the 60 highest, consecutive minutes of each day (11.1 +/- 5.4 strides/min) was correlated with ICD (r = 0.290, P < .01) and ACD (r = 0.453, P < .001). Similarly, the cadences for the highest 1, 5, and 20 consecutive minutes, and the cadence for the 30 highest, nonconsecutive minutes all were correlated with ICD and ACD (P < .05). None of the ambulatory cadences were correlated with ABI (P > .05) or with ischemic window (P > .05).

CONCLUSION

Daily ambulatory cadences are associated with severity of intermittent claudication, as measured by ACD and ICD, but not with peripheral hemodynamic measures.

The association between elevated ankle systolic pressures and peripheral occlusive arterial disease in diabetic and nondiabetic subjects

OBJECTIVE

The presence of a high ankle-brachial index (ABI) is related to stiff ankle arteries due to medial calcification. Recently, this condition has attracted new interest after reports of a worse cardiovascular prognosis, similar to a low ABI. We sought to compare risk factors contributing to a low (< or =0.90) and high (> or =1.40) ABI. Additionally, we hypothesized that in instances of high ABI, occlusive PAD may coexist.

METHOD

This cross-sectional study was conducted at vascular laboratories in a university medical center. The subjects were 510 ambulatory patients (37% had diabetes) previously examined at our vascular laboratories and who responded positively to our invitation. We collected data on smoking, diabetes, hypertension, dyslipidemia, and cardiovascular disease history. The noninvasive assessment of lower limb arteries consisted of the measurement of ABI, toe-brachial index (TBI), and posterior tibial artery peak flow velocity (Pk-PT). A TBI >0.7 and a Pk-PT >10 cm/s were considered normal.

RESULTS

High- and low-ABI were detected, respectively, in 2.1% and 57.8% of limbs. For a low ABI, age (odds ratio [OR], 1.29/10 y), pack-years (OR, 1.08/10 units), and hypertension (OR, 1.90) were independent significant (P < .001) factors. A strong association was found between diabetes and high ABI (OR, 16.0; P < .001). When ABI ranges were compared with TBI and Pk-PT results, those with ABI < or =0.90 and ABI > or =1.40 presented similar patterns of abnormalities. Pk-PT or TBI, or both, was abnormal in more than 80% of cases in both ABI < or =0.90 and > or =1.40 groups. The ABI vs TBI relationship appeared linear in nondiabetic patients, but had an inverted J-shape in diabetic patients, suggesting high ABI masked leg ischemia.

CONCLUSIONS

Diabetes is the dominant risk factor for a high (> or =1.40) ABI. Occlusive PAD is highly prevalent in subjects with high ABI, and these subjects should be considered as PAD-equivalent.

Circulating blood markers and functional impairment in peripheral arterial disease

OBJECTIVES

To determine whether higher levels of inflammatory blood markers, D-dimer, and homocysteine were associated with greater impairment in lower extremity functioning in persons with peripheral arterial disease (PAD).

DESIGN

Cross-sectional.

SETTING

Three Chicago-area medical centers.

PARTICIPANTS

Four hundred twenty-three persons with PAD (ankle-brachial index (ABI) <0.90).

MEASUREMENTS

Lower extremity performance was assessed using the 6-minute walk and with usual- and fast-paced 4-m walking speed. Blood markers were D-dimer, C-reactive protein (CRP), interleukin-6 (IL-6), soluble vascular cellular adhesion molecule-1 (sVCAM-1), soluble intracellular adhesion molecule-1 (sICAM-1), and homocysteine. Calf muscle area was measured using computed tomography.

RESULTS

Adjusting for confounders, higher levels of D-dimer (P<.001), IL-6 (P<.001), sVCAM-1 (P=.006), CRP (P=.01), homocysteine (P=.004), and sICAM-1 (P=.046) were associated with poorer 6-minute walk performance. Higher levels of D-dimer (P<.001), IL-6 (P=.003), sVCAM-1 (P=.001), and homocysteine (P=.005) were associated with slower usual-paced 4-m walking speed. Higher levels of D-dimer, sVCAM-1, sICAM-1, IL-6, and homocysteine were associated with slower fast-paced walking speed. Results were attenuated after additional adjustment for calf muscle area.

CONCLUSION

Higher levels of inflammation and D-dimer were associated with poorer lower extremity performance in participants with PAD, independent of confounders including ABI.

Face-to-Face Interaction Compared with Video Watching on Use of Physical Activity in Peripheral Arterial Disease: A Pilot Trial

Few studies have defined the association of physician-patient communication with physical activity levels in patients with peripheral arterial disease. We hypothesized that a face-to-face intervention versus video watching would improve physical activity levels in patients with peripheral arterial disease. The authors conducted a randomized trial involving 2 interventions. The face-to-face intervention included a brief dialogue with patients to understand their perceptions of peripheral arterial disease and importance of walking. The comparison group watched a video that included an overview of peripheral arterial disease. The primary outcome was changed from baseline to follow-up in levels of physical activity. Fiftyone patients with peripheral arterial disease were randomized. There were no statistically significant differences between the 2 groups in reported activity level or walking ability at 12 weeks. For within group changes, the patients in the video-watching group improved their walking speed (8.5%; SD = 4.1; P = .05). Patients with peripheral arterial disease may benefit from the use of an educational video to increase the use of unsupervised physical activity. Further research is needed to identify interventions that can increase the use of unsupervised physical activity in this population.

Asymptomatic peripheral arterial disease is associated with more adverse lower extremity characteristics than intermittent claudication

BACKGROUND

This study assessed functional performance, calf muscle characteristics, peripheral nerve function, and quality of life in asymptomatic persons with peripheral arterial disease (PAD).

METHODS AND RESULTS

PAD participants (n=465) had an ankle brachial index <0.90. Non-PAD participants (n=292) had an ankle brachial index of 0.90 to 1.30. PAD participants were categorized into leg symptom groups including intermittent claudication (n=215) and always asymptomatic (participants who never experienced exertional leg pain, even during the 6-minute walk; n=72). Calf muscle was measured with computed tomography. Analyses were adjusted for age, sex, race, ankle brachial index, comorbidities, and other confounders. Compared with participants with intermittent claudication, always asymptomatic PAD participants had smaller calf muscle area (4935 versus 5592 mm(2); P<0.001), higher calf muscle percent fat (16.10% versus 9.45%; P<0.001), poorer 6-minute walk performance (966 versus 1129 ft; P=0.0002), slower usual-paced walking speed (P=0.0019), slower fast-paced walking speed (P<0.001), and a poorer Short-Form 36 Physical Functioning score (P=0.016). Compared with an age-matched, sedentary, non-PAD cohort, always asymptomatic PAD participants had smaller calf muscle area (5061 versus 5895 mm(2); P=0.009), poorer 6-minute walk performance (1126 versus 1452 ft; P<0.001), and poorer Walking Impairment Questionnaire speed scores (40.87 versus 57.78; P=0.001).

CONCLUSIONS

Persons with PAD who never experience exertional leg symptoms have poorer functional performance, poorer quality of life, and more adverse calf muscle characteristics compared with persons with intermittent claudication and a sedentary, asymptomatic, age-matched group of non-PAD persons.

Critical review of the ankle brachial index

Ankle brachial index (ABI) has been utilized in the management of peripheral arterial disease (PAD).ABI is a surrogate marker of atherosclerosis and recent studies indicate its utility as a predictor of future cardiovascular disease and all-cause mortality. Even so, this critical test is underutilized. The purpose of this review is to summarize available evidence associated with ABI methodology variances, ABI usage in the treatment of PAD, and ABI efficacy in predicting cardiovascular disease. This review further evaluates how ABI is used in the prognosis and follow-up of lower extremity arterial disease.We reviewed the most current American College of Cardiology guidelines for the management of PAD, the Trans Atlantic Intersociety Consensus (TASC) working group recommendations, and searched the Medline for the following words: ankle brachial index, ABI sensitivity and specificity, and peripheral arterial disease.The ABI is a simple, noninvasive clinical test that should not only be applied to diagnose PAD, but also to provide important prognostic information about future cardiovascular events. Although the ABI has been employed in clinical practice for some time, our review of various studies reveals a lack of standardization regarding both the method of measuring ABI and the cutoff point for abnormal ABI. It is extremely important that we understand all aspects of this crucial test, as it is now being recommended as part of a patient's routine health risk assessment.

Oscillometric measurement of ankle-brachial index

INTRODUCTION

Peripheral arterial disease is a coronary risk equivalent; a low ankle-brachial index (ABI) is indicative of systemic vascular disease, and should place a patient in the high-risk category. Few physicians measure ABI because it is technically challenging and time consuming. Oscillometric blood pressure monitors are readily available and easy to use. The use of a simple method of documenting ABI was assessed and compared with the conventional method.

METHODS

The oscillometric ABI (OABI) was measured for normal volunteers, patients attending a cardiovascular risk clinic (Cardiovascular Risk Factor Reduction Unit [CRFRU] at the University of Saskatchewan, Saskatoon) and patients referred to a vascular laboratory (vasc lab). The latter group had Doppler ABI (DABI) measurements and served to validate OABI. An Omron HEM 711C oscillometric system (Omron Canada Inc) with appropriate cuff size for arm and leg circumference was used.

RESULTS

The mean +/- SEM OABI was 1.13+/-0.08 in normal volunteers (n=26), 1.10+/-0.10 in CRFRU patients (n=11, P not significant) and 1.03+/-0.14 in vasc lab patients (n=57, P<0.05 compared with normal volunteers). No difference was found between sexes, and there was no correlation with age. In the vasc lab group, the correlation with DABI was 0.71 (P<0.05). The sensitivity of OABI to detect DABI of less than 0.9 was 0.71, and the specificity was 0.89. OABI was found to be less sensitive at detecting low values in patients with nonpalpable pulses on physical examination.

CONCLUSION

The OABI is feasible and operator-independent, but does not detect low ABI efficiently. If OABI is abnormal, low DABI is likely. The OABI is less likely to detect disease in patients with nonpalpable peripheral pulses. Such patients are better referred directly to a vascular laboratory for DABI testing.

Profound influence of different methods for determination of the ankle brachial index on the prevalence estimate of peripheral arterial disease

Background

The ankle brachial index (ABI) is an efficient tool for objectively documenting the presence of lower extremity peripheral arterial disease (PAD). However, different methods exist for ABI calculation, which might result in varying PAD prevalence estimates. To address this question, we compared five different methods of ABI calculation using Doppler ultrasound in 6,880 consecutive, unselected primary care patients ≥65 years in the observational getABI study.

Methods

In all calculations, the average systolic pressure of the right and left brachial artery was used as the denominator (however, in case of discrepancies of ≥10 mmHg, the higher reading was used). As nominators, the following pressures were used: the highest arterial ankle pressure of each leg (method #1), the lowest pressure (#2), only the systolic pressure of the tibial posterior artery (#3), only the systolic pressure of the tibial anterior artery (#4), and the systolic pressure of the tibial posterior artery after exercise (#5). An ABI < 0.9 was regarded as evidence of PAD.

Results

The estimated prevalence of PAD was lowest using method #1 (18.0%) and highest using method #2 (34.5%), while the differences in methods #3–#5 were less pronounced. Method #1 resulted in the most accurate estimation of PAD prevalence in the general population. Using the different approaches, the odds ratio for the association of PAD and cardiovascular (CV) events varied between 1.7 and 2.2.

Conclusion

The data demonstrate that different methods for ABI determination clearly affect the estimation of PAD prevalence, but not substantially the strength of the associations between PAD and CV events. Nonetheless, to achieve improved comparability among different studies, one mode of calculation should be universally applied, preferentially method #1.

Measurement of Walking Distance and Speed in Patients With Peripheral Arterial Disease

Background— The maximal walking distance (MWD) performed on a treadmill test remains the “gold standard” in estimating the walking capacity of patients who have peripheral arterial disease with intermittent claudication, although treadmills are not accessible to most physicians. We hypothesized that global positioning system (GPS) recordings could monitor community-based outdoor walking and provide valid information on walking capacity in patients with peripheral arterial disease.

Methods and Results— We studied 24 patients (6 women) with arterial claudication (median [25th to 75th percentile] values: 57 years old [48 to 67 years], 169 cm tall [164 to 172 cm], weight 81 kg [71 to 86 kg], and ankle-brachial index 0.64 [0.56 to 0.74]). MWD on the treadmill was 184 m (144 to 246 m), which was compared with the results of self-reported MWD, the distance score from the Walking Impairment Questionnaire, MWD observed during a 6-minute walking test, and MWD measured over a GPS-recorded unconstrained outdoor walk in a public park. Self-reported MWD, Walking Impairment Questionnaire distance score, 6-minute walking test score, and GPS-measured MWD were 300 m (163 to 500 m), 28% (15% to 47%), 405 m (338 to 441 m), and 609 m (283 to 1287 m), respectively. The best correlation with MWD on the treadmill test was obtained with the MWD measured by the GPS (Spearman r =0.81, P <0.001).

Conclusions— Outdoor walking capacity measured by a low-cost GPS is a potentially innovative way to study the walking capacity of patients with peripheral arterial disease. It opens new perspectives in the study of walking capacity for vascular patients with claudication under free-living conditions or for physicians who do not have a treadmill.

Associations between lower extremity ischemia, upper and lower extremity strength, and functional impairment with peripheral arterial disease

OBJECTIVES

To identify associations between lower extremity ischemia and leg strength, leg power, and hand grip in persons with and without lower extremity peripheral arterial disease (PAD). To determine whether poorer strength may mediate poorer lower extremity performance in persons with lower arterial brachial index (ABI) levels.

DESIGN

Cross-sectional.

SETTING

Academic medical centers.

PARTICIPANTS

Four hundred twenty-four persons with PAD and 271 without PAD.

MEASUREMENTS

Isometric knee extension and plantarflexion strength and handgrip strength were measured using a computer-linked strength chair. Knee extension power was measured using the Nottingham leg rig. ABI, 6-minute walk, and usual and fastest 4-m walking velocity were measured. Results were adjusted for potential confounders.

RESULTS

Lower ABI values were associated with lower plantarflexion strength (P trend=.04) and lower knee extension power (P trend <.001). There were no significant associations between ABI and handgrip or knee extension isometric strength. Significant associations between ABI and measures of lower extremity performance were attenuated after additional adjustment for measures of strength.

CONCLUSION

These results are consistent with the hypothesis that lower extremity ischemia impairs strength specifically in distal lower extremity muscles. Associations between lower extremity ischemia and impaired lower extremity strength may mediate associations between lower ABI values and greater functional impairment.

The impact of peripheral arterial disease on health-related quality of life in the Peripheral Arterial Disease Awareness, Risk, and Treatment: New Resources for Survival (PARTNERS) Program

Abstract

This study tested the hypothesis that patients with PAD have impaired health-related quality of life (HRQoL) to a degree similar to that of patients with other types of cardiovascular disease (other-CVD), and also evaluated the clinical features of PAD associated with impaired HRQoL. This was a cross-sectional study in 350 primary care practice sites nationwide with 6,499 participants. The reference group had no clinical or hemodynamic evidence of PAD or other-CVD; the PAD group had an ankle-brachial index < 0.90 or a prior history of PAD; the other-CVD group had a clinical history of cardiac or cerebral vascular disease (but no PAD), and the combined PAD-other-CVD group included both diagnoses. Individuals were assessed using four HRQoL questionnaires including the Walking Impairment Questionnaire (WIQ), Medical Outcomes Study SF-36 (SF-36), Cantril Ladder of Life and the PAD Quality of Life questionnaire. PAD patients had lower WIQ distance scores than the other-CVD group. Both the PAD and other-CVD groups had significantly lower SF-36 Physical Function scores compared with the reference group. The WIQ revealed that PAD patients were more limited by calf pain, whereas other-CVD patients were more limited by chest pain, shortness of breath and palpitations. In conclusion, in this nationwide study, one of the first to directly compare the HRQoL burden of CVD with that of PAD, the evaluation of PAD in office practice revealed a HRQoL burden as great in magnitude as in patients with other forms of CVD.

Does Lower-Extremity Arterial Disease Predict Future Falling Among Older Men and Women?

The purpose of this study was to determine whether lower-extremity peripheral arterial disease (PAD) is an independent risk factor for falls among older persons. Men and women 55 years old and older participated. Subjects with PAD (n = 86) were identified from a noninvasive vascular laboratory and a general medicine practice. Randomly selected controls without PAD (n = 82) were identified from the same medicine practice. Subjects were categorized into PAD (ankle brachial index, <0.90) or controls (ankle brachial index, 0.90 to 1.50). Subjects underwent a comprehensive baseline evaluation for fall risk. Prospective fall data were obtained using monthly mail-in postcards and structured telephone interviews over a mean follow-up of 9.6 ± 2.9 months. Two independent investigators blinded to PAD status reviewed each fall incident for its eligibility. A total of 37 subjects (22%) had at least 1 eligible fall. In an unadjusted Cox regression model, the relative risk of falling was lower among PAD subjects than among controls (relative risk, 0.54; 95% confidence interval, 0.28 to 1.06). After adjustment for age, gender, history of frequent falls in the last year, number of comorbidities, and balance and gait abnormalities, PAD was significantly associated with a lower risk of falling (relative risk, 0.43; 95% confidence interval, 0.21 to 0.87) as compared with controls. PAD is associated with a lower risk of falling as compared with persons without PAD among older men and women. Future study is needed to determine whether reduced levels of physical activity among patients with PAD account for the lower rate of falling observed here.

Patterns of ambulatory activity in subjects with and without intermittent claudication

PURPOSE

This study compared the patterns of ambulatory activity in subjects with and without intermittent claudication.

METHODS

The study participants were 98 subjects limited by intermittent claudication and 129 controls who were matched for age, gender, and race. Subjects were assessed on their ambulatory activity patterns for 1 week with a small, lightweight step activity monitor attached to the ankle using elastic Velcro (Velcro Industries BV, Manchester, NH) straps above the lateral malleolus of the right leg. The step activity monitor recorded the number of strides taken on a minute-to-minute basis, the time spent ambulating, and the time and number of strides measured at low (<15 strides/min), medium (15 to 30 strides/min), and high (>30 strides/min) cadences.

RESULTS

Subjects with intermittent claudication took fewer total strides each day than the controls (3149 +/- 1557 strides/d vs 4230 +/- 1708 strides/d; P < .001) and fewer strides at medium (1228 +/- 660 strides/day vs 1638 +/- 724 strides/day; P = .001) and high (766 +/- 753 strides/day vs 1285 +/- 1029 strides/day; P < .001) cadences. Subjects with intermittent claudication also had a lower daily average cadence than the controls (11.8 +/- 2.9 strides/min vs 13.5 +/- 3.1 strides/min; P < .001) and spent less total time ambulating each day (264 +/- 109 min/day vs 312 +/- 96 min/day; P = .034), primarily at medium (58 +/- 30 min/day vs 75 +/- 32 min/day; P < .001) and at high (19 +/- 17 min/day vs 30 +/- 22 min/day; P = .001) cadences.

CONCLUSION

Intermittent claudication is associated with lower total daily ambulatory activity owing both to less time ambulating and to fewer strides taken while ambulating, particularly at moderate and high cadences.

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

BACKGROUND

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Baseline functional performance predicts the rate of mobility loss in persons with peripheral arterial disease

OBJECTIVES

We compared rates of mobility loss among persons with versus without peripheral arterial disease (PAD). Associations between baseline functional performance and mobility loss in persons with and without PAD were studied.

BACKGROUND

Persons with PAD have poorer functional performance than persons without PAD. The prognostic value of poorer performance in persons with PAD is unknown.

METHODS

Participants were 398 persons with and 240 without PAD who were free of mobility impairment at baseline. Participants were followed for a median of 50 months. Baseline measures included the 6-min walk and the Short Physical Performance Battery score. Mobility status, assessed annually, was defined as the self-reported loss of the ability to walk one-quarter mile or walk up and down one flight of stairs without assistance.

RESULTS

Adjusting for age and gender, we found that PAD participants had a greater rate of mobility loss than persons without PAD (hazard ratio [HR] 1.63; 95% confidence interval [CI] 1.03 to 2.56). This difference was not statistically significant after additional adjustment for baseline performance. Among PAD participants, risk of mobility loss in the lowest versus the 2 highest quartiles of baseline performance were as follows: HR 9.65 (95% CI 3.35 to 27.77, p < 0.001) for the 6-min walk and HR 12.84 (95% CI 4.64 to 35.55, p < 0.001) for the Short Physical Performance Battery when adjusting for confounders.

CONCLUSIONS

Persons with PAD experience greater mobility loss than persons without PAD. This association was explained by poorer baseline functional performance among participants with PAD. Poorer lower extremity performance predicts increased mobility loss in persons with and without PAD.

Elevated levels of inflammation, d-dimer, and homocysteine are associated with adverse calf muscle characteristics and reduced calf strength in peripheral arterial disease

OBJECTIVES

This study determined whether increased levels of inflammatory blood markers, D-dimer, and homocysteine were associated with smaller calf skeletal muscle area, increased calf muscle percent fat, reduced calf muscle density, and poorer calf strength in persons with lower extremity peripheral arterial disease (PAD).

BACKGROUND

Elevated levels of inflammatory markers and D-dimer are associated with greater functional impairment and functional decline in persons with PAD. Mechanisms of these associations are unknown.

METHODS

Participants were 423 persons with PAD. Calf muscle area, percent fat, and density were measured with computed tomography. Physical activity levels were measured objectively over 7 days with the Caltrac (Muscle Dynamics Fitness Network, Inc., Rocklin, California) vertical accelerometer. Isometric plantarflexion strength was measured. Analyses were adjusted for age, gender, race, comorbidities, the ankle-brachial index, and other potential confounders.

RESULTS

Higher levels of D-dimer (p = 0.014), C-reactive protein (CRP) (p = 0.002), interleukin (IL)-6 (p < 0.001), and soluble vascular cellular adhesion molecule (sVCAM)-1 (p = 0.008) were associated with smaller calf muscle area. Higher sVCAM-1 (p = 0.004) and IL-6 (p = 0.017) were associated with higher calf muscle percent fat. Higher D-dimer (p < 0.001), sVCAM-1 (p < 0.001), and homocysteine (p = 0.014) were associated with lower calf muscle density. These associations were generally unchanged after additional adjustment for physical activity. Higher sVCAM-1 (p = 0.013) was associated with lower calf strength.

CONCLUSIONS

These data show, for the first time, that higher levels of inflammation, D-dimer, and homocysteine are associated with more adverse calf muscle characteristics in persons with PAD. These associations may contribute to previously established associations between elevated biomarkers and functional impairment and functional decline in PAD.

Exercise performance in patients with peripheral arterial disease who have different types of exertional leg pain

OBJECTIVE

This study compared the exercise performance of patients with peripheral arterial disease (PAD) who have different types of exertional leg pain.

METHODS

Patients with PAD were classified into one of four groups according to the San Diego Claudication Questionnaire: intermittent claudication (n = 406), atypical exertional leg pain causing patients to stop (n = 125), atypical exertional leg pain in which patients were able to continue walking (n = 81), and leg pain on exertion and rest (n = 103). Patients were assessed on the primary outcome measures of ankle-brachial index (ABI), treadmill exercise measures, and ischemic window.

RESULTS

All patients experienced leg pain consistent with intermittent claudication during a standardized treadmill test. The mean (+/- SD) initial claudication distance (ICD) was similar (P = .642) among patients with intermittent claudication (168 +/- 160 meters), atypical exertional leg pain causing patients to stop (157 +/- 130 meters), atypical exertional leg pain in which patients were able to continue walking (180 +/- 149 meters), and leg pain on exertion and rest (151 +/- 136 meters). The absolute claudication distance (ACD) was similar (P = .648) in the four respective groups (382 +/- 232, 378 +/- 237, 400 +/- 245, and 369 +/- 236 meters). Similarly, the ischemic window, expressed as the area under the curve (AUC) after treadmill exercise, was similar (P = .863) in these groups (189 +/- 137, 208 +/- 183, 193 +/- 143, and 199 +/- 119 AUC).

CONCLUSION

PAD patients with different types of exertional leg pain, all limited by intermittent claudication during a standardized treadmill test, were remarkably similar in ICD, ACD, and ischemic window. Thus, the presence of ambulatory symptoms should be of primary clinical concern in evaluating PAD patients regardless of whether they are consistent with classic intermittent claudication.

Physical activity, walking exercise, and calf skeletal muscle characteristics in patients with peripheral arterial disease

OBJECTIVE

This cross-sectional study was set in an academic medical center and conducted to identify associations of physical activity level and walking exercise frequency with calf skeletal muscle characteristics in individuals with lower extremity peripheral arterial disease (PAD).

METHODS

Calf muscle characteristics in 439 men and women with PAD were measured with computed tomography at 66.67% of the distance between the distal and proximal tibia. Physical activity was measured continuously during 7 days with a vertical accelerometer. Patient report was used to determine the number of blocks walked during the past week and walking exercise frequency. Results were adjusted for age, sex, race, comorbidities, ankle-brachial index, body mass index, smoking, and other confounders.

RESULTS

For both objective and subjective measures, more physically active PAD participants had higher calf muscle area and muscle density. Calf muscle area across tertiles of accelerometer-measured physical activity were first activity tertile, 5071 mm(2); second activity tertile: 5612 mm(2); and third activity tertile, 5869 mm(2) (P < .001). Calf muscle density across tertiles of patient-reported blocks walked during the past week were first activity tertile, 31.4 mg/cm(3); second activity tertile, 33.0 mg/cm(3); and third activity tertile, 33.8 mg/cm(3) (P < .001). No significant associations were found between walking exercise frequency and calf muscle characteristics.

CONCLUSION

Among participants with PAD, higher physical activity levels, measured by accelerometer and by patient-reported blocks walked per week, were associated with more favorable calf muscle characteristics. In contrast, more frequent patient-reported walking exercise was not associated with more or less favorable calf muscle characteristics. Results suggest that clinicians should encourage their patients to increase their walking activity during daily life.

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.

High prevalence of proximal claudication among patients with patent aortobifemoral bypasses

BACKGROUND

Proximal (ie, buttock, hip) claudication can result from impaired perfusion in the hypogastric area after aortobifemoral bypass (ABF) despite normal femorodistal blood flow provided by the patent bypass. The proportion of patients that experience proximal claudication after ABF is unknown, and arguments for the vascular origin of symptoms specifically at the proximal level have never been reported.

METHODS

This was a prospective study set in an institutional practice of ambulatory patients referred for a systematic survey of their previous ABF bypass. Among the 131 eligible patients, 10 refused to participate and 16 were unable to walk on a treadmill. The 105 studied patients (94 men, 11 women) were a mean age of 63 +/- 10 years, and the median delay from surgery was 2 years (range, 4 months to 26 years). We used a modified version of the San Diego Claudication Questionnaire administered both at rest before the treadmill study and again after the treadmill test. Transcutaneous oxygen pressure (TcPO2) at the buttock level was used to evaluate blood flow impairment during exercise at the proximal level, with blood flow impairment defined as buttock minus chest TcPO2 decrease in excess of -15 mm Hg.

RESULTS

Thirty patients reported proximal exercise-related pain consistent with vascular criteria by history before exercise. However, 59 patients (56%) reported symptoms compatible with proximal claudication, and TcPO2 values were abnormal on one or both sides in 52. The persistence of at least one (prograde or retrograde) pathway to the hypogastric circulation, determined by review of operative details from the aortobifemoral bypass and angiography, did not significantly decrease the proportion of patients reporting proximal claudication by history (26%) or on treadmill (55%) compared with those with bilateral hypogastric occlusion (33% by history, P = .51 compared with at least one prograde hypogastric pathway and 61% based on treadmill test, P = .65 compared with at least one prograde hypogastric pathway).

CONCLUSION

The present study shows that (1) the proportion of ABF patients with a median bypass age of 2 years that report proximal claudication is high (28%), (2) this proportion is significantly higher when claudication is detected by treadmill exercise tests, (3) a vascular origin (or at least contribution) is likely 88% of the proximal symptoms observed on treadmill, (4) the presence of proximal claudication with associated abnormal TcPO(2) results increases the risk of walking impairment in affected patients, and (5) preservation of at least one internal iliac artery to allow prograde or retrograde flow to the hypogastric vascular bed does not decrease the risk of proximal claudication after ABF surgery. A vascular origin of (or at least contribution to) most of the proximal exercise-related symptoms should always be discussed in patients with patent ABF bypass.

Low ankle-brachial index predicts an adverse 1-year outcome after acute coronary and cerebrovascular events

BACKGROUND

Low ankle-brachial Index (ABI) identifies patients with symptomatic and asymptomatic peripheral arterial disease. The aim of this study was to correlate ABI value (normal or low) with 1-year clinical outcome in patients hospitalized for acute coronary syndromes or cerebrovascular diseases (CVD).

METHODS

ABI was measured in consecutive patients hospitalized because of acute myocardial infarction, unstable angina, stroke or transient ischemic attack (TIA). An ABI lower than or equal to 0.90 was considered abnormal. The primary outcome of the study was the composite of non-fatal acute myocardial infarction, non-fatal ischemic stroke, and death from any cause during the year following the index event.

RESULTS

An abnormal ABI was found in 27.2% of 1003 patients with acute coronary syndromes, and in 33.5% of 755 patients with acute CVD. After a median follow-up of 372 days, the frequency of the primary outcome was 10.8% (57/526) in patients with abnormal ABI and 5.9% (73/1232) in patients with normal ABI [odds ratio (OR) 1.96; 95% CI 1.36-2.81]. Death was more common in patients with abnormal ABI (OR 2.05; 95% CI 1.31-3.22). Cardiovascular mortality accounted for 81.7% of overall mortality. ABI was predictive of adverse outcome after adjustment for vascular risk factors in the logistic regression analysis (OR 1.93; 95% CI 1.24-3.01). The predictive value of ABI was mainly accounted for by patients hospitalized for acute coronary syndromes (adverse outcome: 12.8% in patients with abnormal ABI and 5.9% in patients with normal ABI, OR 2.35; 95% CI 1.47-3.76).

CONCLUSIONS

An abnormal ABI can be found in one-third of patients hospitalized for acute coronary or cerebrovascular events and is a predictor of an adverse 1-year outcome.

Peripheral Arterial Disease: A Review of Disease Awareness and Management

BACKGROUND

Peripheral arterial disease (PAD) is a progressive atherosclerotic condition affecting approximately 27 million people in North America and Europe. Albeit a common clinical malady, it is underrecognized and undertreated.

OBJECTIVE

The goal of this article was to review the pathophysiology, clinical implications, diagnosis, and management of PAD.

METHODS

Relevant published information was identified through a search of MEDLINE (1966-2006). Search terms used included peripheral vascular diseases, intermittent claudication, arterial occlusive diseases, antiplatelet therapy, HMG-CoA reductase inhibitors, risk factors, smoking cessation, adrenergic beta-antagonists, and angiotensin-converting enzymes.

RESULTS

PAD is associated with an increased risk of cardiovascular and cerebrovascular disease as well as a reduction in quality of life. PAD symptoms are not always present with the disease; therefore, improvements in screening methods for at-risk patients are necessary. Patients at risk for PAD should be routinely screened, and appropriate management--including antiplatelet therapy and risk factor modifications--should be initiated once the disease is recognized. Risk factor modifications should include smoking cessation as well as blood pressure and cholesterol management. Acetylsalicylic acid (ASA) is the antiplatelet of choice, and clopidogrel should be used as an alternative if ASA therapy is contraindicated or an intolerance is present. Cilostazol has a minimal role for the symptomatic relief in patients with disabling intermittent claudication. All patients with PAD should be treated with a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor and potentially an angiotensin-converting enzyme inhibitor. Beta-Blockers should not be avoided unless documented worsening of symptoms is associated with their use.

CONCLUSIONS

Patients at risk for PAD should be routinely screened, and appropriate management including antiplatelet therapy and risk factor modifications should be initiated once the disease is recognized.

Established and evolving medical therapies for claudication in patients with peripheral arterial disease

Claudication resulting from peripheral arterial disease causes substantial impairment in the ability to carry out normal daily activities. The medical treatments for claudication that are currently available are exercise rehabilitation and one drug, cilostazol. Pentoxifylline, which improves red cell deformability, lowers fibrinogen levels and decreases platelet aggregation, has been used historically, but frequency of use has declined because of limited effectiveness. Exercise rehabilitation, while efficacious, has been underused in the past. This therapy is, however, currently the subject of several large research projects. These studies are investigating mechanisms by which exercise therapy could benefit people with claudication and are also directly comparing it with other therapies. Concurrently, several new drug therapies for claudication are in the process of being evaluated. These research efforts might increase the available armamentarium and thereby help to alleviate the impairments associated with this symptom. The aim of this article is to discuss the current medical treatments being developed for use in patients with claudication resulting from peripheral arterial disease.

Lower extremity nerve function in patients with lower extremity ischemia

BACKGROUND

We determined whether lower extremity ischemia, as measured by the ankle brachial index (ABI), is associated with impaired lower extremity nerve function.

METHODS

Participants included 478 persons with peripheral arterial disease (PAD) identified from noninvasive vascular laboratories and 292 persons without PAD identified from a general medicine practice and noninvasive vascular laboratories. Peripheral arterial disease was defined as an ABI lower than 0.90 (mild PAD: ABI, 0.70 to <0.90; moderate PAD: ABI, 0.50 to <0.70; and severe PAD: ABI, <0.50). The ABI and electrophysiologic measures of the peroneal, sural, and ulnar nerves were obtained.

RESULTS

Among 546 participants without diabetes, PAD participants had significantly impaired peripheral nerve function in the upper and lower extremities compared with non-PAD participants. After adjusting for age, sex, race, smoking, height, body mass index, recruitment source, alcohol use, disk disease, spinal stenosis, cardiac disease, and cerebrovascular disease, these associations were not statistically significant. After adjusting for confounders among nondiabetic participants, those with severe PAD (ABI, <0.50) had poorer peroneal nerve conduction velocity (NCV) compared with participants without PAD (42.6 vs 44.8 m/s; P = .003) and poorer peroneal NCV compared with participants with mild PAD (42.6 vs 45.0 m/s; P = .001) or moderate PAD (42.6 vs 44.1 m/s; P = .03). Among 224 participants with diabetes, after adjusting for confounders, PAD was associated with poorer peroneal NCV (40.8 vs 43.5 m/s; P = .01), sural nerve amplitude (3.1 vs 4.8 muV; P = .045), and ulnar NCV (47.6 vs 50.2 m/s; P = .03) compared with those without PAD.

CONCLUSIONS

Our findings suggest that leg ischemia impairs peroneal nerve function. This association is less strong in patients with diabetes, perhaps because of the overriding influence of diabetes on peripheral nerve function. Clinicians should consider screening for PAD in patients with idiopathic peroneal nerve dysfunction. Peripheral arterial disease-associated nerve dysfunction may contribute to PAD-associated functional impairment.

The effect of novel cardiovascular risk factors on the ethnic-specific odds for peripheral arterial disease in the Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVES

The purpose of this study was to: 1) determine the significance and magnitude of associations between novel cardiovascular disease (CVD) risk factors and peripheral arterial disease (PAD) after adjustment for traditional risk factors; and 2) ascertain the extent to which novel risk factors explain the excess or lower risk for PAD in different ethnic groups.

BACKGROUND

Previous reports have found a significant difference in the risk of PAD by ethnic group, with some of the risk difference attributed to different levels of traditional CVD risk factors.

METHODS

A total of 6,814 individuals free of clinically apparent CVD were enrolled in the MESA (Multiethnic Study of Atherosclerosis) and underwent standardized testing for the presence of PAD by the ankle-brachial index. These subjects also had fasting blood drawn for serum cholesterol, glucose, and a number of novel biomarkers for CVD. Non-Hispanic whites were the largest ethnic group (38%), followed by African Americans (28%), Hispanics (22%), and Chinese (12%).

RESULTS

In this cross-sectional analysis, 6,653 subjects with an ankle brachial index <1.40 were analyzed. The mean (SD) age was 62.2 (10.2) years, and 52.9% were women. Interleukin-6, fibrinogen, D-dimer, and homocysteine were significantly associated with PAD after adjustment for traditional CVD risk factors. Compared with non-Hispanic whites and after adjustment for traditional and "novel" risk factors, the odds for PAD were 1.47 (95% confidence interval [CI]: 1.07 to 2.02) times higher in African Americans, while being 0.45 (95% CI: 0.29 to 0.70) and 0.44 (95% CI: 0.24 to 0.78) in Hispanics and Chinese, respectively.

CONCLUSIONS

Ethnic associations with PAD remained significant even after adjustment for traditional and novel risk factors. This suggests that unknown factors may account for the residual ethnic differences in PAD.

Physical activity during daily life and mortality in patients with peripheral arterial disease

BACKGROUND

We determined whether patients with lower-extremity peripheral arterial disease (PAD) who are more physically active during daily life have lower mortality rates than PAD patients who are less active.

METHODS AND RESULTS

Participants were 460 men and women with PAD (mean age 71.9+/-8.4 years) followed up for 57 months (interquartile range 36.6 to 61.9 months). At baseline, participants were interviewed about their physical activity. Vertical accelerometers measured physical activity continuously over 7 days in 225 participants. Analyses were adjusted for age, sex, race, body mass index, hypertension, smoking, comorbidities, total cholesterol, HDL cholesterol, leg symptoms, and ankle-brachial index. At 57-month follow-up, 134 participants (29%) had died, including 75 participants (33%) who wore accelerometers. Higher baseline physical activity levels measured by vertical accelerometer were associated with lower all-cause mortality (P(trend)=0.003). Relative to PAD participants in the highest quartile of accelerometer-measured physical activity, those in the lowest quartile had higher total mortality (hazard ratio 3.48, 95% confidence interval 1.23 to 9.87, P=0.019). Similar results were observed for the combined outcome of cardiovascular events or cardiovascular mortality (P(trend)=0.005). Higher numbers of stair flights climbed during 1 week were associated with lower total mortality (P(trend)=0.035).

CONCLUSIONS

PAD patients with higher physical activity during daily life have reduced mortality and cardiovascular events compared with PAD patients with the lowest physical activity, independent of confounders. Further study is needed to determine whether interventions that increase physical activity during daily life are associated with improved survival in patients with PAD.

Obesity, weight change, and functional decline in peripheral arterial disease

BACKGROUND

Our objectives were to determine whether obesity is associated with a greater functional decline compared with the ideal body mass index (BMI) among persons with peripheral arterial disease (PAD) and to determine the associations between weight gain and loss and functional declines in PAD. We hypothesized that baseline obesity and weight gain during follow-up would each be associated with functional declines in persons with PAD.

METHODS

The design was a prospective cohort study. The subjects were 389 men and women with PAD (mean ankle-brachial index, 0.65 +/- 0.14) who were followed up prospectively for a median of 48 months. The main outcome measures were functional assessments (6-minute walk, usual- and rapid-paced 4-m walking speed, and summary performance score). Weight and height were measured at baseline and annually. Results were adjusted for age, sex, race, comorbidities, ankle-brachial index, education, leg symptoms, exercise status, depressive symptoms, pack-years of cigarette smoking, prior-year functioning, and patterns of missing data.

RESULTS

Compared with those with a baseline BMI between 20 and 25 kg/m2, PAD participants with baseline BMI greater than 30 kg/m2 had a significantly greater average annual decline in 6-minute walk performance (-13.1 vs -26.5 m/y; P = .004), usual-paced 4-m walking velocity (-0.028 vs -0.055 m/s per year; P = .024), and fast-paced 4-m walking velocity (-0.053 vs -0.086 m/s per year; P = .012). Persons with weight gain between 5 and 10 pounds after baseline who walked for exercise regularly had significantly less decline in the 6-minute walk than persons without significant weight change who did not walk for exercise (P = .04).

CONCLUSIONS

Obesity is associated with functional decline in persons with PAD. Walking exercise may protect against functional decline in PAD persons with modest weight gain.

Exertional leg pain in patients with and without peripheral arterial disease

BACKGROUND

Although exertional leg pain is a hallmark of peripheral arterial disease (PAD) and can occur in persons without PAD, symptom variation has received inadequate attention.

METHODS AND RESULTS

Three cohort studies were combined for cross-sectional analysis. The San Diego Claudication Questionnaire assessed exertional leg pain. PAD was defined as ankle brachial index (ABI) < or =0.90 or history of lower-extremity revascularization. Of 3658 subjects, 3629 were analyzed after exclusions. Of these, 24.1% had PAD in 1 or both legs. There was a stepwise decrease in average ABI, from no pain to pain on exertion and rest, noncalf pain, atypical calf pain, and classic claudication (P=0.002). When stratified by PAD, this trend was no longer significant. Legs with ABIs >0.90 and revascularization had pain distributions intermediate between that of normal legs (ABI, 1.00 to 1.39) and legs with ABIs < or =0.90. Compared with normal legs, legs with low-normal (0.91 to 0.99) and high-normal (> or =1.40) ABIs had higher pain rates, suggesting borderline disease and vascular stiffness, respectively. Multivariable logistic regression models showed that ABI was a strong correlate of pain category throughout the ABI range. Independently of ABI, age, male sex, diabetes, smoking history, high body mass index, myocardial infarction, and previous revascularization were all significant correlates of exertional leg pain.

CONCLUSIONS

No category of exertional leg pain was sufficiently sensitive or specific for routine PAD diagnosis. Legs with low-normal and high-normal ABIs appeared to have ischemic leg pain; thus, a "normal ABI" is likely to range from 1.00 to 1.39. In addition to ABI, several risk variables were independent correlates of exertional leg pain.

Functional decline in lower-extremity peripheral arterial disease: associations with comorbidity, gender, and race

PURPOSE

To identify comorbidities associated with increased rates of functional decline in persons with lower-extremity peripheral arterial disease (PAD). We also determined whether female sex and black race were associated with greater functional decline than male sex and white race, respectively, in PAD.

METHODS

Three-hundred ninety-seven men and women with PAD were followed prospectively for a median of 36 months. The presence of comorbid illnesses was determined with medical record review, patient report, medications, laboratory values, and a primary care physician questionnaire. Functional outcomes, measured annually, included the 6-minute walk, usual-paced and fast-paced 4-meter walking speed, and summary performance score. The summary performance score is a composite measure of lower-extremity functioning (score range, 0 to 12; 12 = best).

RESULTS

Adjusting for known and potential confounders, PAD patients with pulmonary disease had a significantly greater average annual decline in 6-minute walk performance of -34.02 ft/y (95% confidence interval [CI], -60.42 to -7.63; P = .012), rapid-paced 4-meter walk speed of -0.028 m/s/y (95% CI, -0.054 to -0.001; P = .042), and summary performance score of -0.460/y (95% CI, -0.762 to -0.157; P = .003) compared with those without pulmonary disease. PAD patients with spinal stenosis had a greater average annual decline in 6-minute walk performance of -77.4 ft/y (95% CI, -18.9 to -35.8; P < .001) and usual-paced 4-meter walking velocity of -0.045 m/s/y (95% CI, -0.081 to -0.009; P = .014) compared with participants without spinal stenosis.

CONCLUSION

At 3-year follow-up, pulmonary disease and spinal stenosis were each associated with a significant decline in functioning among persons with PAD. In contrast, female sex and black race were not associated with functional decline among persons with PAD.

D-dimer and inflammatory markers as predictors of functional decline in men and women with and without peripheral arterial disease

OBJECTIVES

To determine whether higher circulating levels of inflammatory and thrombotic markers are associated with greater decline in lower extremity performance.

DESIGN

Prospective cohort.

SETTING

Academic medical center.

PARTICIPANTS

Three hundred thirty-seven men and women with lower extremity peripheral arterial disease (PAD) and 215 without PAD.

MEASUREMENTS

Objective measures of leg function, including the 6-minute walk and Short Physical Performance Battery (SPPB), were obtained at baseline and annually for 3 years. D-dimer, high-sensitivity C-reactive protein, serum amyloid A, and fibrinogen levels were measured at baseline. Participants were categorized into one of three groups, ranging from low to high levels of inflammation, depending on the number of individual blood factors in the lowest and highest tertiles for each corresponding blood factor.

RESULTS

Adjusting for age, sex, race, ankle brachial index, comorbidities, and other confounders, greater inflammation was associated with greater decline in the SPPB (P=.008). Results were similar when repeated in participants with and without PAD separately (P for trend=.04 for participants with PAD and .07 for participants without PAD). In fully adjusted analyses, there were no significant associations between inflammation group and decline in 6-minute walk performance.

CONCLUSION

Higher baseline levels of inflammatory markers and D-dimer were associated with greater decline in the SPPB at 3-year follow-up in persons with and without PAD.

Get the LEAD Out

Lower extremity arterial disease affects approximately one third of individuals 66 years of age and older and has a high risk for nonhealing wounds, infection, and limb loss. Much wound care is given by or under the direction of nurses. Therefore, the assessment and management of these patients presents many opportunities and challenges. Assessment is the cornerstone of effective care, but traditional methods of lower extremity arterial assessment, such as pulse palpation and pain history, are insufficient to determine the presence and extent of ischemia. Recently published national guidelines for assessment and management of patients with lower extremity wounds have recommended using noninvasive tests such as the ankle brachial index and toe brachial index to rule out lower extremity arterial disease, which complicates wound healing. However, the ankle brachial index can be falsely elevated in patients with diabetes and renal failure because of calcification of the arteries, which causes them to be incompressible. In these situations, it has been advised to obtain a toe pressure or toe brachial index because digital arteries are usually less affected by calcification. There is a paucity of data about the knowledge of principles and performance of the ankle brachial index/toe brachial index by nurses, particularly in the United States, using pocket-sized portable Doppler equipment. Therefore, the purpose of this article is to provide an overview and synthesis of relevant studies and published expert opinion regarding noninvasive arterial assessment using ankle brachial and toe brachial indexes as a basis for developing protocols for performing the tests and identifying gaps in research where further investigation is needed.