Automated ankle-brachial pressure index measurement by clinical staff for peripheral arterial disease diagnosis in nondiabetic and diabetic patients

Prevalence of peripheral artery disease in the elderly population in urban and rural areas of Central Africa: the EPIDEMCA study

OBJECTIVE

Data on peripheral artery disease in Africa are sparse and limited to urban areas. Given the urban/rural socio-economical gradient in these countries, we sought to determine the prevalence and risk factors of peripheral artery disease in urban and rural areas of two countries in Central Africa.

METHODS

Individuals ≥65 years old living in two urban and rural areas of the Republic of Central Africa (ROC) and the Central African Republic (CAR) were invited. Demographic, clinical and biological data were collected. Ankle-brachial index ≤0.90 defined peripheral artery disease.

RESULTS

Among the 1871 participants (age 73 years, 62% female) the prevalence of peripheral artery disease was 14.8%, higher in ROC than in CAR (17.4% vs. 12.2%, p = 0.007) and higher in females than males (16.6% vs. 11.9%, p = 0.012). The prevalence of peripheral artery disease increased with age, respectively at 10.9%, 14.9%, 15.1% and 22.2% for age bands of 65-69, 70-74, 75-79 and 80+years (p < 0.001). Higher rates of peripheral artery disease were found in urban areas in ROC (20.7% vs. 14.4% in rural areas, p = 0.011), but not in CAR (11.5% vs. 12.9%, p = NS). In multivariate analysis, peripheral artery disease was significantly associated with age (odds ratio (OR): 1.03; p = 0.004), dyslipidaemia (OR: 1.88; p = 0.003), smoking (OR: 1.78; p = 0.003), obesity (OR: 1.98; p = 0.034) and underweight (OR: 1.49; p = 0.023). Regular alcohol drinking was associated with decreased risk of peripheral artery disease (OR: 0.73; p = 0.044).

CONCLUSION

The prevalence of peripheral artery disease in the elderly is high in Africa, especially in females. In ROC, with a higher urban-rural socio-economic gradient, peripheral artery disease is more frequent in the urban areas.

Time and reliability issues associated with automatic vs. manual measurements of Ankle to Brachial pressure Index (ABI) following heavy load exercise

OBJECTIVES

Ankle to brachial index after heavy load exercise is the most accurate way of diagnosing minor arterial lesions in athletes, such as endofibrosis. The reliability and practical aspects of ankle to brachial index measurements after heavy-load exercise have not been studied. The purpose of this study was to analyze the interest of oscillometric automatic vs. manual Doppler measurements, for the calculation of ankle to brachial index, after heavy-load exercise in athletes.

DESIGN

Prospective single-center study.

METHODS

Fifteen healthy trained athletes performed an incremental test twice. Ankle to brachial index measurements were performed at Rest, as soon as possible after exercise (Rec-0), and then started at the 3rd minute of recovery (Rec-3), by two operators using each one of the two ankle to brachial index measurement methods.

RESULTS

Mean times for automatic vs. manual ankle to brachial availability were 99 ± 18 s vs. 113 ± 25 s (p = 0.005) and 44 ± 25 s vs. 53 ± 12 s (p = 0.001) respectively at Rec-0 and Rec-3. Ankle to brachial index values from the two methods were highly correlated (r = 0.89). Mean absolute differences of automatic vs. manual ankle to brachial values from test-retest were 0.04 ± 0.05 vs. 0.08 ± 0.08 (p > 0.05) and 0.07 ± 0.05 vs. 0.09 ± 0.10 (p > 0.05) at Rest and Rec-0.

CONCLUSIONS

Automatic method allows obtaining faster and simultaneously post-exercise ankle to brachial index measurement compare to the manual Doppler. This time issue does not result in a significant change in absolute ankle to brachial index values, nor in the absolute differences of these in test-retest. Nevertheless, the test-retest variability of post-exercise ankle to brachial index results seems smaller with the automatic than the manual method.

Interaction between diabetes and a high ankle-brachial index on mortality risk

OBJECTIVE

Low ankle-brachial index (ABI) is a predictor of increased mortality. The impact of a high ABI on mortality is less studied. Moreover, diabetes is frequently associated with high ABI and, because of specific mechanisms in diabetic vascular diseases, the relationship with prognosis may be unique. Therefore, our aim was to compare mortality in individuals with and without diabetes according to abnormally low and high ABI.

DESIGN AND METHODS

We studied the association between ABI and all-cause and cardiovascular mortality in 6986 participants from the REACH registry, a cohort of 45 years and older stable outpatients at high cardiovascular risk (2875 (41.1%) with diabetes) followed for 4 years.

RESULTS

ABI was normal (0.91-1.29) in 49.5%, low (≤0.9) in 47.5%, and high (≥1.3) in 2.9% of participants. During follow up, 9.9% of participants died (6.5% from cardiovascular causes). A low ABI was associated with cardiovascular mortality (adjusted hazard ratio, HR, 1.98, 95% CI 1.62-2.41) and all-cause mortality (HR 2.01, 95% CI 1.72-2.36), without heterogeneity according to diabetes. In contrast, high ABI was associated with higher risk of all-cause mortality in individuals with diabetes (HR 2.11, 95% CI 1.16-3.84), but not without diabetes (HR 0.82, 95% CI 0.36-1.85; p-value for interaction 0.07). The trend was similar for cardiovascular mortality (HR 2.13, 95% CI 1.03-4.44 and HR 1.05, 95% CI 0.43-2.59 with and without diabetes, respectively; p-value for interaction 0.24).

CONCLUSIONS

In the REACH registry, low ABI was associated with mortality, similarly in individuals without and with diabetes, whereas the association with high ABI was only observed in patients with diabetes.

Indocyanine green angiography for the diagnosis of peripheral arterial disease with isolated infrapopliteal lesions

BACKGROUND

In this study, we evaluated the accuracy of the indocyanine green angiography (ICGA) test to diagnose peripheral arterial disease (PAD) with isolated infrapopliteal lesions.

METHODS

This study was undertaken from a retrospective review of PAD patients with isolated infrapopliteal lesions who underwent ICGA between November 2012 and July 2013. We calculated the ICGA parameters while comparing the findings with the ankle-brachial index (ABI) and toe-brachial index (TBI) in patients with infrapopliteal lesions.

RESULTS

Twenty-three limbs with isolated infrapopliteal lesions in 14 PAD patients and 15 limbs without arterial lesions in 9 control patients were examined using ABI, TBI, and ICGA. The Td 90% (the time elapsed from the maximum intensity to 90% of the maximum intensity) correlated most significantly with the ABI value. A cutoff value of Td 90% >25 sec also significantly correlated with the presence of PAD (sensitivity, 82.6%).

CONCLUSIONS

ICGA might therefore be useful for assessing the peripheral perfusion quantitatively, even in PAD patients with isolated infrapopliteal lesions. The use of Td 90% on ICGA may also be effective for accurately estimating the presence of PAD.

Validation study of automated oscillometric measurement of the ankle-brachial index for lower arterial occlusive disease by comparison with computed tomography angiography

The ankle-brachial index (ABI) determined by the oscillometric method has been shown to reliably detect peripheral arterial disease (PAD), with highly correlations with the Doppler method. However, most of these studies were shown in cohorts with a small number of PAD patients, and no imaging studies have been performed. The purpose of this study is to evaluate the diagnostic accuracy and optimal threshold of oscillometric ABI for detecting PAD using computed tomography angiography (CTA) as a gold standard in a cohort that consists mostly of PAD patients. This retrospective study included 108 consecutive patients with 216 limbs. ABI measured by an oscillometric device was compared with CTA. The diagnostic accuracy of oscillometric ABI to detect ≥50% and ≥75% stenosis confirmed by CTA and the optimal ABI cutoff values were evaluated using receiver operating characteristic (ROC) curve analysis. The oscillometric ABI could not be measured in nine limbs. The mean ABI was 0.72±0.31. The areas under the ROC curves (AUCs) for detecting ≥50% and ≥75% stenosis with oscillometric ABI were 0.919 and 0.918, respectively. The optimal ABI cutoff values to detect these levels of stenosis were 0.99 (sensitivity, 90%: specificity, 85%) and 0.87 (sensitivity, 84%: specificity, 89%), respectively. If patients with diabetes mellitus (DM) were analyzed separately, the AUC for detecting ≥75% stenosis was 0.888. Oscillometric ABI had a high diagnostic accuracy to detect PAD using CTA as a gold standard. The diagnostic ability of ABI to detect PAD could be impaired by the presence of DM.

Influence of peripheral vascular calcification on efficiency of screening tests for peripheral arterial occlusive disease in diabetes--a cross-sectional study

AIMS

Pulse palpation and ankle brachial index are recommended to screen for peripheral arterial occlusive disease in people with diabetes. However, vascular calcification can be associated with false negative tests (arteriopathy present despite normal screening tests). We therefore studied the impact of peripheral vascular calcification on the performance of these tests.

METHODS

This cross-sectional study included 200 people with diabetes at high risk of cardiovascular disease. The main exclusion factor was an estimated glomerular filtration rate < 30 ml/min. Peripheral arterial occlusive disease was diagnosed by colour duplex ultrasonography and peripheral vascular calcification scored by computed tomography scan. We measured sensitivity, specificity, predictive values, accuracy and likelihood ratios of pulse palpation and ankle brachial index, and looked for the impact of calcification on false negative tests (arteriopathy present despite normal screening tests).

RESULTS

Ankle brachial index alone had poor sensitivity and negative predictive value and high negative likelihood ratio. Pulse palpation had higher sensitivity and negative predictive value. An abnormal pulse palpation, defined by weak or missing pulses, combined with an abnormal ankle brachial index, had the highest sensitivity and negative predictive value (92.3 and 89.8%, respectively). Vascular calcification score was higher in patients with false negative tests, for both pulse palpation and ankle brachial index (P < 0.0001 for all). Ankle systolic blood pressure was higher in patients with false negative tests for pulse palpation (P = 0.004).

CONCLUSIONS

Below-knee vascular calcification gave a high rate of false negative results for ankle brachial index. Refined pulse palpation combined with ankle brachial index remained the best strategy to screen for peripheral arteriopathy.

Decrease in ankle-brachial index over time and cardiovascular outcomes in patients with hemodialysis

INTRODUCTION

Abnormal ankle-brachial index (ABI) is associated with increased morbidity and mortality in hemodialysis patients. However, whether the decrease in ABI over time carries the prognostic value is unknown. The aim of this study was to assess whether the decrease in ABI over time was a good predictor of poor cardiovascular (CV) prognosis in hemodialysis patients.

METHODS

This study enrolled 234 routine hemodialysis patients and 173 patients completed the follow-up. The ABI was measured by an ABI-form device at baseline and at the first year follow-up. The ΔABI was defined as ABI measured at the first year follow-up minus ABI measured at baseline. Progressors of ABI were defined as patients with ΔABI < -0.3. CV events were defined as CV death, hospitalization for unstable angina, nonfatal myocardial infarction, hospitalization for arrhythmia, hospitalization for congestive heart failure and stroke.

RESULTS

The follow-up period was 37.8 ± 11.1 months. In the multivariate analysis, progressors of ABI (hazard ratio, 2.71; 95% confidence interval, 1.10-6.68, P = 0.03), decreased albumin and increased high-sensitivity C-reactive protein were associated with increased CV events.

CONCLUSIONS

This longitudinal study showed ΔABI < -0.3 was independently associated with an increase in CV events. Hence, a great decrease in ABI over time might be a useful indicator of poor CV prognosis in hemodialysis patients.

Ankle brachial index using an automatic blood pressure device in occupational medicine: relevance in routine examination and comparison with Framingham cardio-vascular risk score

AIM

The aim of this study was to assess the feasibility and relevance of determining ankle brachial index (ABI) using an automatic blood pressure device in subjects seen for their annual routine examination by occupational physicians and to compare the obtained ABI with the Framingham score.

PATIENTS AND METHODS

Sixteen physicians randomly recruited 634 subjects in 12 departments of occupational medicine. Subjects aged between 40 and 60 years underwent a determination of ABI using an OMRON HM 722 device and the analysis of Framingham score. Other analysed variables were: sex, age, smoking habit, hypertension, diabetes, hypercholesterolemia, glycaemia, total cholesterol, HDL and LDL cholesterol and triglycerides levels.

RESULTS

Mean age of the population studied was 48.1 ± 6.0 years; 73% were men, 36% were smokers, 14% had hypertension, 3.3% diabetes and 22% hypercholesterolemia. Biochemical values were glycaemia 0.90 ± 0.30 g/l, total cholesterol 2.10 ± 0.4 g/l, HDL cholesterol level 0.50 ± 0.20 g/l, LDL cholesterol level 1.30 ± 0.40 g/l, and triglycerides 1.40 ± 1.0 g/l. Mean ABI were 1.1 ± 0.1 in both legs. Mean Framingham score was 8.2 ±  5.4%. Only 20 subjects (3%) had an ABI < 0.90. No relation was found between pathological ABI and Framingham score (abnormal ABI : 9.9 ± 5.5 vs. normal ABI : 8.2 ± 5.4, NS).

CONCLUSION

The determination of ABI using a simple commercially available automatic blood pressure device is feasible and easy to implement by preventive or general physicians in all kinds of routine examinations. In our opinion automatic ABI very easy and quick to determine provides, in addition to Framingham score, a simple and useful tool to detect subjects at high cardio-vascular risk.

Automated oscillometric determination of the ankle-brachial index: a systematic review and meta-analysis

Measurement of the ankle-brachial index (ABI) using a Doppler device is widely used to identify subjects with peripheral artery disease (PAD), and those who are at high risk of cardiovascular disease. This paper presents a systematic review (Medline/PubMed, Embase and Cochrane) and meta-analysis of studies assessing the usefulness of automated oscillometric devices for ABI estimation and PAD detection compared with the conventional Doppler method. A total of 25 studies including 4186 subjects were analyzed. A random-effects model analysis showed that the average oscillometric ABI was similar to the Doppler ABI (mean difference ± s.e. 0.020 ± 0.018, P=0.3) but that the absolute differences were significant (0.048 ± 0.009, P<0.01). The pooled correlation coefficient (r) between the oscillometric and Doppler ABI was 0.71 ± 0.05. Simultaneous arm-leg measurements resulted in a smaller difference between the average oscillometric ABI value and the average Doppler ABI value than did sequential measurements (-0.012 ± 0.022 vs. 0.040 ± 0.026, respectively, P<0.01). The average sensitivity and specificity of the oscillometric ABI estimation in PAD diagnosis was 69 ± 6% and 96 ± 1%, respectively (with Doppler ABI taken as the reference). These data suggest that an automated ABI measurement obtained by oscillometric blood pressure monitors is a reliable and practical alternative to the conventional Doppler measurement for the detection of PAD. To increase the sensitivity of the PAD diagnosis based on an oscillometric ABI, a higher threshold of 1.0 might be preferable.

Chapter II: Diagnostic methods

Non-invasive vascular studies can provide crucial information on the presence, location, and severity of critical limb ischaemia (CLI), as well as the initial assessment or treatment planning. Ankle-brachial index with Doppler ultrasound, despite limitations in diabetic and end-stage renal failure patients, is the first-line evaluation of CLI. In this group of patients, toe-brachial index measurement may better establish the diagnosis. Other non-invasive measurements, such as segmental limb pressure, continuous-wave Doppler analysis and pulse volume recording, are of limited accuracy. Transcutaneous oxygen pressure (TcPO(2)) measurement may be of value when rest pain and ulcerations of the foot are present. Duplex ultrasound is the most important non-invasive tool in CLI patients combining haemodynamic evaluation with imaging modality. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are the next imaging studies in the algorithm for CLI. Both CTA and MRA have been proven effective in aiding the decision-making of clinicians and accurate planning of intervention. The data acquired with CTA and MRA can be manipulated in a multiplanar and 3D fashion and can offer exquisite detail. CTA results are generally equivalent to MRA, and both compare favourably with contrast angiography. The individual use of different imaging modalities depends on local availability, experience, and costs. Contrast angiography represents the gold standard, provides detailed information about arterial anatomy, and is recommended when revascularisation is needed.

Accuracy of ankle-brachial index obtained by automated blood pressure measuring devices in patients with diabetes mellitus

BACKGROUND

Upper arm automated blood pressure devices are widely available and could be used to estimate the ankle-brachial index.

METHODS

We conducted a trial to determine the equivalence of ankle-brachial index estimated by an upper arm blood pressure measuring device as index method compared to the handheld Doppler method as the reference standard. A total of 110 patients with diabetes mellitus were sequentially examined by two methods.

RESULTS

The prevalence of peripheral arterial disease was 32%. The index method obtained valid measurements in 104 (95%) patients. Ankle-brachial index was lower with the index method compared to the reference standard (mean difference: -0.05; 95% confidence interval [CI]: -0.50 to 0.39). This confidence interval was above the boundaries clinically established as equivalence margins in our study. The kappa agreement between two methods was 0.45. The performance of the index method was: sensitivity: 67%; specificity: 87%; positive likelihood ratio: 5.25; negative likelihood ratio: 0.18; positive predictive value: 71%; negative predictive value: 85%; and the area under the receiving operating characteristic curve: 0.87 (95% CI: 0.78-0.93).

CONCLUSION

Upper arm automated blood pressure measuring devices cannot replace the handheld Doppler method to estimate the ankle-brachial index in patients with diabetes mellitus.

Automated determination of the ankle-brachial index using an oscillometric blood pressure monitor: validation vs. Doppler measurement and cardiovascular risk factor profile

The ankle-brachial index (ABI) is a method used widely for peripheral arterial disease (PAD) diagnosis and cardiovascular risk prediction. This study validated automated ABI measurements taken using an oscillometric blood pressure (BP) monitor allowing simultaneous arm-leg BP measurements. A total of 93 patients (hypertension 83%; dyslipidemia 72%; diabetes 45%; cardiovascular disease 23%; smoking 15%) were submitted to Doppler and automated ABI measurements, performed using a professional oscillometric BP monitor (Microlife WatchBP Office; triplicate simultaneous arm-leg BP measurements), in a randomized order. The mean difference between the Doppler reading (1.08 ± 0.17) and (1) the first oscillometric ABI reading was 0.03 ± 0.11, (2) the average of two oscillometric readings was 0.02 ± 0.10 and (3) the average of three oscillometric readings was 0.02 ± 0.09 (P < 0.01 for all). Strong correlations were found between oscillometric and Doppler ABI (r 0.80, 0.85 and 0.86 for single and average of two and three oscillometric readings, respectively; P < 0.001 for all). Agreement between oscillometric and Doppler ABI in diagnosing PAD (Doppler ABI < 0.9) was found in 95% of cases (κ 0.79; agreement in diabetics: 94%, κ 0.79). A receiver operating characteristic (ROC) curve revealed area under the curve at 0.98, with a 0.97 oscillometric ABI cutoff for optimal sensitivity (92%) and specificity (92%) in diagnosing PAD. Average time for automated ABI measurement was 5.8 vs. 9.3 min for Doppler (P < 0.001). Doppler and oscillometric ABI were associated and predicted (multivariate regression analysis) by the same cardiovascular risk factors (pulse pressure, smoking and cardiovascular disease history). Automated ABI measurement using a professional BP monitor allowing simultaneous arm-leg BP measurements appears to be a reliable and faster alternative to Doppler measurement.

Use and utility of ankle brachial index in patients with diabetes

Ankle brachial index (ABI) is a simple method to screen peripheral arterial disease (PAD) and to evaluate cardiovascular (CV) prognosis in the general population. Measuring it requires a hand-held Doppler probe but it can be done also with an automatic device. ABI is an effective tool for clinical practice or clinical studies. However, in diabetic patients, it has some specific caveats. Sensitivity of the standard threshold of 0.9 appears to be lower in diabetic patients with complications. Moreover, highly frequent arterial medial calcifications in diabetes increase ABI. It has been demonstrated that measurements >1.3 are well correlated with both an increased prevalence of PAD and CV risk. Therefore, ABI thresholds of less than 0.9 and more than 1.3 are highly suspicious for PAD and high CV risk in diabetic patients. However, when there is concomitant clinical peripheral neuropathy or high risk of arterial calcification, the efficiency of ABI seems to be limited. In this case, other methods should be applied, toe pressure, in particular. Thus, the ABI could be used in patients with diabetes, but values should be interpreted with precision, according to the clinical situation.