Calculation Of Ankle-brachial Index Research Articles

Perfusion imaging techniques in lower extremity peripheral arterial disease.

Lower limb peripheral arterial disease (PAD) characterizes the impairment of blood flow to extremities caused by arterial stenoses or occlusions. Evaluation of PAD is based on clinical examination, calculation of ankle-brachial index and imaging studies such as ultrasound, CT, MRI and digital subtraction angiography. These modalities provide significant information about location, extension and severity of macrovasular lesions in lower extremity arterial system. However, they can be also used to evaluate limb perfusion, using appropriate techniques and protocols. This information may be valuable for assessment of the severity of ischemia and detection of hypoperfused areas. Moreover, they can be used for planning of revascularization strategy in patients with severe PAD and evaluation of therapeutic outcome. These techniques may also determine prognosis and amputation risk in patients with PAD. This review gives a basic overview of the perfusion techniques for lower limbs provided by imaging modalities such as ultrasound, CT, MRI, digital subtraction angiography and scintigraphy and their clinical applications for evaluation of PAD and revascularization outcome.

Association of chronic inflammation with cardiovascular risk in chronic obstructive pulmonary disease-A cross-sectional study.

Background and AimsCOPD is progressive lung disease with known higher cardiovascular (CV) risk, mainly attributed to smoking of cigarettes as the main etiological factor of disease. The aim of this study was to compare CV risk in patients with COPD to control groups of smokers and non‐COPD and to investigate the relation of lung function variables, COPD severity, and smoking with Systemic Coronary Risk Estimation (SCORE) risk calculation, arterial stiffness (AS) values, and biological systemic inflammatory markers.MethodsA total of 208 subjects were included in this study: 61 subjects diagnosed with COPD, 83 smokers without COPD, and 64 nonsmokers without COPD. Medical history and clinical data were recorded, including assessment of pulmonary function and AS, calculation of ankle‐brachial index, blood analysis, and CV risk assessment by SCORE risk calculation.ResultsSubjects with COPD had significantly higher values of SCORE calculation of risk, central aortic pressure, AS, and markers of systemic inflammation compared to control groups of smokers and nonsmokers without COPD (p < 0.001). Furthermore, statistically significant increase in hs‐CRP concentration was found between the COPD group and the control group of non‐COPD smokers (p < 0.001), and a statistically significantly higher SCORE calculation was found in the COPD group compared to control groups of smokers and nonsmokers without COPD (p < 0.001).ConclusionThe results of the research support further identification and research of biological markers and simple specific tests such as arteriography that will enable progress in personalized treatment of patients with COPD and better primary and secondary prevention of comorbidities with the aim of improved treatment outcome.

Infrared Thermography as a Diagnostic Tool for the Assessment of Patients with Symptomatic Peripheral Arterial Disease Undergoing Infrafemoral Endovascular Revascularisations

Aim: The aim of this study was to evaluate the utility and reliability of temperature foot changes measured by infrared thermography (IRT) for the evaluation of patients with atherosclerotic peripheral arterial disease (PAD) before and after endovascular revascularisation. Methods: This is an observational prospective study carried out on symptomatic PAD patients. Evaluations consisted of a clinical examination, duplex scan with ankle–brachial index calculation (ABI) and IRT measurements with infrared camera FLIR-ONE connected to a smartphone with android technology. Locations on the foot sampled with IRT were the anterior tibial, pedal, posterior and arcuate arteries. Results obtained with IRT on the symptomatic foot were compared to the contralateral foot and with the ABI values obtained bilaterally before and 24 h after revascularisation. Results: Within one year, 40 patients were enrolled, among whom 87,5% suffered from critical limb ischaemia. In three patients, it was impossible to obtain ABI measurements because of ulcerations on the limb. Skin temperature changes obtained by IRT between the symptomatic limb and the contralateral limb had a mean difference of 1.7 °C (range: 1.1–2.2 °C), p < 0.001. There was a positive correlation between ABI and temperature values of the limb needed for treatment before revascularisation (p = 0.025; r = 0.36) and after revascularisation (p = 0.024, r = 0.31). The technical success rate was 100% in all cases, achieving a significant increase in temperature at all points of the foot analysed, with a median change of 2 °C (p < 0.001). Conclusion: IRT is a safe, reliable and simple application. It could be a valuable tool for the assessment of the clinical presentation and severity of foot blood perfusion in symptomatic PAD patients and the evaluation of the technical success of endovascular revascularisation. IRT might have a role in follow-up of revascularisation procedures.

Usefulness of ankle-brachial index calculated using diastolic blood pressure for prediction of mortality in patients with acute myocardial infarction.

A low ankle-brachial index (ABI) calculated using systolic blood pressure (SBP) (ABIsbp) is associated with poor cardiovascular outcome in patients with acute myocardial infarction (AMI). ABI is always calculated using SBP clinically. However, there was no study investigating ABI calculated using mean artery pressure (MAP)(ABImap) and diastolic blood pressure (DBP)(ABIdbp) for mortality prediction in AMI patients. Therefore, our study was aimed to investigate the issue. 199 AMI patients were enrolled. Different ABIs were measured by an ABI-form device. The median follow-up to mortality was 64months. There were 40 cardiovascular and 137 all-cause mortality. The best cutoff values of ABImbp and ABIdbp for mortality prediction were 0.91 and 0.78, respectively. After multivariate analysis, only ABIdbp and ABIdbp<0.78 could predict cardiovascular mortality (P≤.047). However, all of six ABI parameters, including ABIsbp, ABImap, ABIdbp, ABIsbp<0.90, ABImap<0.91, and ABIdbp<0.78, could predict all-cause mortality (P≤.048). In a direct comparison of six ABI models for prediction of all-cause mortality, basic model+ABIdbp <0.78 had the highest predictive value (P≤.025). In conclusion, only ABIdbp and ABIdbp<0.78 could predict cardiovascular and all-cause mortality after multivariate analysis in our study. Furthermore, when adding into a basic model, ABIdbp<0.78 had the highest additively predictive value for all-cause mortality in the six ABI parameters. Hence, calculation of ABI using DBP except SBP might provide an extra benefit in prediction of cardiovascular and all-cause mortality in AMI patients.

Abstract P305: Alternative Ankle Brachial Index Calculation and CVD Events and Mortality: The Multi-Ethnic Study of Atherosclerosis (MESA)

Introduction: The ankle brachial index (ABI) is independently associated with cardiovascular disease (CVD) events and mortality. The recommended ABI calculation for the ankle pressure involves taking the higher (ABI-TRAD) of the dorsalis pedis (DP) or posterior tibial (PT) arteries in the lower of the two legs. However, little is known about using the lower (ALT-ABI) of the DP/PT in evaluating CVD endpoints. Methods: Using a multiethnic cohort free of known CVD disease at baseline, participants with complete ABI assessment were followed for incident CVD events, CVD mortality and all-cause mortality. ABI was assessed as categories: low (≤0.9), borderline (0.9-1.0), low-normal (1.0-1.1), normal (1.1-1.4) and high (≥1.4) and continuously using ALT-ABI. Leg symptoms were assessed with the San Diego Claudication Questionnaire. We used cox models to assess associations between ALT-ABI and outcomes adjusting for age, gender, race/ethnicity, ASCVD risk score and leg symptoms. Results: Of the 6,669 participants with complete ABI measures, the mean ALT-ABI was 1.03 +/- 0.12 versus ABI-TRAD of 1.10 +/- 0.11. The mean age of participants was 62 years and 1,625 (24.4%) reported some type of leg pain with walking. At a median follow up of 14.2 years, 1,214 deaths, 657 CVD events, and 288 CVD-specific deaths had occurred. Of the 824 individuals with low ALT-ABI, 581 (70.5%) had an ABI &gt; 0.9 using ABI-TRAD. As seen in the Table, lower values and categories of ALT-ABI were associated with increased risk of CVD events, CVD and all-cause mortality. Conclusions: Using ALT-ABI identified more individuals with an ABI ≤ 0.9. The ALT-ABI is significantly associated with CVD outcomes, even in asymptomatic individuals. Significant risk increases were present even in those with a low-normal ALT-ABI. While clinical guidelines recommend further workup and risk reduction in individuals with leg symptoms and an ABI-TRAD ≤ 0.9, this method of ABI calculation and cutoff may misidentify individuals at-risk for adverse CV outcomes.

Tips and tricks for facilitating teaching of Doppler waveforms and ankle-brachial index in undergraduate level: A practical guide

Although the measurement of ankle-brachial index (ABI) is considered a fundamental skill in assessment and diagnosis of peripheral arterial disease and a predictive tool for cardiovascular events, real-world practice shows that the experience of many health professionals is far from ideal. Not only teaching and practice of ABI measurement in undergraduate medical curricula are limited but various mistakes in the process of calculation, estimation, and interpretation of ABI results in the postgraduate practice have also been documented. Because vascular surgery is a core subject in our medical school, we deal with the difficulties and challenges that undergraduate medical students and nurses face to measure and comprehend ABI. We came up with useful tips and maneuvers to overcome these difficulties. Accordingly, this article provides twelve easy-to-follow useful tips to enhance and facilitate the teaching and comprehension of ABI. Moreover, it favors the simultaneous teaching of Doppler arterial waveform examination as a means to facilitate accurate interpretation and validation of ABI results.

THE FEATURES OF ATHEROSCLEROTIC PROCESS DEVELOPMENT AND ACUTE CORONARY SYNDROME COURSE IN PATIENTS WITHOUT DYSLIPIDEMIA

The aim is to study the conditions of appearance and the features of course of the acute coronary syndrome (ACS) in patients with normal rates of lipid metabolism and to assess the influence of additional risk factors (uinary acid, C-reactive protein, fibrinogen) on the development of atherosclerotic process by assessment of surrogate markers of atherosclerosis the thickness of intima-media complex (TIMC) of carotid arteries (СА), the presence of atherosclerotic plaque (AP) in CA, the value of ankle-brachial index (ABI)) in patients with ACS without dyslipidemia (DLP). Materials and methods. The study included 66 patients without DLP (50 men and 16 women, the mean age - 53,7±10,6 years) with ACS, divided in groups depending on its forms: 1 group – patients with instable angina (IA), 2 group – patients with myocardium infraction (MI) without ST segment elevation and 3 group – patients with MI with ST segment elevation. The level of serum acid, C-reactive protein, fibrinogen in blood serum were detected and ultrasound examination of СА with detection of CA TIMC, presence of atherosclerotic plaque and measuring of arterial pressure on upper and low extremities with ABI calculation was carried out. Results. Among examined patients MI with ST segment elevation was diagnosed in 33 persons (50,0%); MI without ST segment elevation – in 18 (27,3%) and IA – in 15 (22,7%). The complicated ACS was observed in 20 (30,30%) persons. The value of CA TIMC among patients with MI with ST segment elevation was reliably higher than in patients with MI without ST segment elevation (р&lt;0,001), and ABI was reliably lower in persons with MI and ST segment elevation (р&lt;0,05) and IA (р&lt;0,05) than in patients with MI without ST segment elevation. Correlative analysis demonstrated the interconnection between the levels of inflammation indicators (C-reactive protein, fibrinogen) in the blood serum and the value of CA TIMC and ABI. Conclusions. The persons without DLP need additional examination (detection of C-reactive protein, fibrinogen levels in blood serum, ultrasound of CA and detection of ABI) for more precise evaluation of ACS risk.

Abstract W P143: Ankle-brachial Index Predicts Extracranial Vascular Events After Transient Ischemic Attacks. Data From The Promapa Study

The ankle brachial index (ABI) is a known measure of lower-limb peripheral artery disease (PAD), as well as an independent predictor of vascular events. Various methods of ABI calculation have been described. The traditional method (ABI-TM) uses the higher ankle pressure as a numerator and it results in higher specificity. The alternative method (ABI-AM) takes the lower ankle pressure as numerator. It is associated with better sensitivity. Our goal was to compare the prognostic value of abnormal ABI (ABI &lt;=0.9), determined by the two methods, in order to predict subsequent stroke and extracranial vascular events (EVE) in transient ischemic attack (TIA) patients from a multicenter study. Methods: We analyzed data from consecutive 1137 patients with TIA from the multicenter PROMAPA study in which ABI was determined. We determined risk of stroke recurrence (SR) and EVE (ischemic cardiopathy or peripheral arterial disease) at one year of follow up. Results: A total of 616 (54.2%) subjects fulfilled all inclusion criteria. The risk of SR and EVE was 4.7% and 2.1%, respectively. The proportion of abnormal ABI differed according to the method used: 11.5% ABI-TM versus 38.0 ABI-AM (p=0.001). In both situations, abnormal ABI was related to the association of &gt;1 risk factors and large artery atherosclerosis. SR was not predicted by abnormal ABI. However, only abnormal ABI-AM was significantly associated with EVE (p=0.003). Cox proportional-hazards multivariate analyses identify the association of &gt; 1 risk factors (Hazard Ratio [HR] 4.7, 95% CI 1.1-21.2. p=0.045) and abnormal ABI-AM (HR 4.0, 95% CI 1.1-14.6, p=0.035) as independent predictors of EVE. Conclusion: ABI using the lower ankle pressure as numerator is associated with EVE after TIA. The measurement of ABI using the lower ankle pressure as numerator among TIA patients appeared to be useful to identify patients with risk of EVE and to plan adequate prevention therapies or specific diagnostic protocols.

Ankle-Brachial Index Assessment: Does it Matter how arm Pressures are Measured?

Introduction —The ankle-brachial index (ABI) is an essential tool used not only in screening for peripheral artery disease (PAD) but also in deciding treatment options of the patient with known PAD. Most vascular laboratories have standardized testing, i.e., Doppler measurement of the arm and ankle pressures in ABI calculation. However, some centers still rely on auscultation with a stethoscope to measure arm pressure. This study sought to determine any differences in ABI calculation between the two techniques. Methods —Permission for the study was obtained by the Institutional Review Boards of Des Moines University and the Iowa Heath-Des Moines System. We first calculated the ABI in a group of 50 healthy volunteers with no history of PAD (control group) by using both Doppler arm pressure and stethoscope arm pressure and Doppler-derived ankle pressures. This represented our “normal” population. We enrolled patients in two Intersocietal Commission for the Accreditation of Vascular Laboratories–accredited Vascular Laboratories at the Iowa Methodist Medical Center (Des Moines, IA) and the Iowa Clinic (West Des Moines, IA) to perform similar Doppler and stethoscope arm pressure and Doppler ankle pressures for ABI determinations in 50 patients (study group). Results —In the comparison group of healthy volunteers, the mean Doppler ABI was 1.18 ± 0.17 in the left leg and 1.22 ± 0.21 in the right leg. Using stethoscope arm pressure measurement, we found that the mean left leg ABI was 1.18 ± 0.17 and 1.17 ± 0.20 in the right leg. The study group of patients showed a Doppler arm pressure determination of ABI in the left leg of 1.02 ± 0.24 and 1.02 ± 0.23 in the right leg. Stethoscope ABI calculation for the study patients showed a mean left leg ABI of 1.03 ± 0.24 and in the right leg of 1.04 ± 0.24. A test–retest reliability analysis was then performed via the parallel model. Cronbach's alpha was then calculated to ascertain the level of agreement between the two ABI data sets (Doppler versus stethoscope ABI) in both the control and study patient groups. The equality of variance was confirmed by the chi-squared test (χ2 = 0.532, df = 1, p &gt; 0.05) for the patient group and 0.972 for the normal population (df = 1, p &gt; 0.05) indicating equal variance in both groups and therefore no difference between test results by method of arm blood pressure assessment. The reliability scale estimate was alpha = 0.99 for the patients and alpha = 0.90 for the normal comparison group, confirming a high degree of correspondence between the two measurement approaches. There was a tendency toward a greater degree of variance in the comparison group of healthy volunteers. Testing was performed by less-experienced, third-year podiatry medical students and may reflect an “experience” factor in measuring ankle and arm pressures, but the differences were not statistically significant. Conclusions —Our study showed very little difference in ABI calculation between Doppler versus stethoscope determination of the highest arm pressure. It appears that both techniques produced similar results. On the basis of our findings, ABI calculations can be performed with the use of either technique, provided they are standardized to one method of arm pressure determination.

Automated photoplethysmography-based determination of ankle-brachial index: a validation study against Doppler sonography

Determination of ankle-brachial-index (ABI) by manual Doppler is well established to screen for lower extremity arterial disease (LEAD) and to predict cardiovascular risk. A new generation of digital-controlled devices promises automated ABI determination. The aim of this study was to determine comparability of automated photoplethysmography (PPG)-derived ABI calculation with the Doppler-ABI algorithm commonly used in cohort studies. Automated PPG-based ABI measurements [Vascular Explorer (VE) and Vicorder (VI)] were recorded from 112 limbs of healthy subjects and 22 limbs of patients with confirmed LEAD. Validity was evaluated on the basis of receiver-operating characteristic (ROC) analysis of clinical status and concordance with Doppler-ABI. Differences between cuff inflation [inf]- and deflation [def]-based method were studied in VE. PPG-based ABI values were higher compared to Doppler-ABI (VI +0.06, VEinf +0.15, VEdef +0.09, p < 0.001, respectively). The difference was pronounced in pathological (<0.9), borderline (0.9-0.99) and low normal (1.0-1.09) ABI, but less in ABI ≥1.1. However, ROC analysis revealed excellent diagnostic value for LEAD (sensitivity/specificity) and comparable area under the curve at method-adapted ABI thresholds for all methods: Doppler (95/90 %, 0.95), VI (75/96 %, 0.91), VEinf (85/89 %, 0.93) and VEdef (80/98 %, 0.94). Digital-controlled PPG-based ABI determination is a useful diagnostic application for LEAD. However, the systematic higher ABI in PPG-based measurement compared to Doppler and remarkable differences between the deflationary and inflationary method are critical for the interpretation of borderline and low normal ABI values where precise reading is essential to detect mild LEAD and subclinical disease and to predict cardiovascular risk.

Very Low Frequency of PAD in People with CHD in Six Middle Eastern Countries

We read with interest the article by Al-Thani et al. [1] reporting a very low frequency (2.6%) of peripheral arterial disease (PAD) in people with acute coronary syndrome in a multicenter study conducted in six Middle Eastern countries. A recent multicenter study in Turkey showed 20% prevalence of PAD in people with established cardiovascular disease or who were at risk for atherosclerotic diseases [2]. Diabetes that was present in 70% of the participants in their study is actually a major cause of arterial stiffness or calcification, which frequently results in misclassification of diabetics in ankle brachial index (ABI) testing by causing paradoxically high values [3]. In this context, it would be utmost helpful if the authors could provide some data related to the prevalence of a high ABI (>1.4) in their study population, so that the readers could recognize whether a high ABI potentially influenced the frequency of a low ABI. Another point that should be noted is the method of assessment of PAD by ABI testing. In recent years, many societies published detailed consensus guidelines on the definition and management of PAD [4–6]. Collectively, the ABI cut-off value for the diagnosis of PAD is currently accepted as ≤0.9. Although ABI of <0.8 can be found in several surveys as the diagnostic threshold, adherence to guidelines and their updates would be a superior evidence-based approach. In such case, it could be speculated that the prevalence of PAD would be recorded some higher in the study by Al-Thani et al. A final concern is the need for a correct calculation of ABI. As explained clearly in the TASC II guidelines, [4] higher readings of dorsalis pedis or tibialis posterior arteries should be used as the numerator in the index formula. However, Al-Thani et al. used the average (i.e., mean of dorsalis pedis plus tibialis posterior records) systolic blood pressure readings in each ankle as the numerator in order to calculate the ABI ratio. Compared to guideline recommendations, this method obviously results in use of lower values for any ankle especially when one of the readings is lower than the other, causing an increase in the frequency of a low ABI. Opposite to our concern regarding the ABI cut-off in the previous section, such a calculation could further reduce the reported prevalence of PAD in this multicenter large scale survey. However, through a scientific view, this does not eliminate the potential limitations. We guess that the readers would appreciate if the authors could comment on these issues.

Target Organ Damage in Hypertension

Target Organ Damage in Hypertension

Risk factors related to low ankle-brachial index measured by traditional and modified definition in hypertensive elderly patients.

Peripheral arterial disease (PAD) increases with age and ankle-brachial index (ABI) ≤ 0.9 is a noninvasive marker of PAD. The purpose of this study was to identify risk factors related to a low ABI in the elderly using two different methods of ABI calculation (traditional and modified definition using lower instead of higher ankle pressure). A cross-sectional study was carried out with 65 hypertensive patients aged 65 years or older. PAD was present in 18% of individuals by current ABI definition and in 32% by modified method. Diabetes, cardiovascular diseases, metabolic syndrome, higher levels of systolic blood pressure and pulse pressure, elevated risk by Framingham Risk Score (FRS), and a higher number of total and antihypertensive drugs in use were associated with low ABI by both definitions. Smoking and LDL-cholesterol were associated with low ABI only by the modified definition. Low ABI by the modified definition detected 9 new cases of PAD but cardiovascular risk had not been considered high in 3 patients when calculated by FRS. In conclusion, given that a simple modification of ABI calculation would be able to identify more patients at high risk, it should be considered for cardiovascular risk prediction in all elderly hypertensive outpatients.

Measurement of blood pressure, ankle blood pressure and calculation of ankle brachial index in general practice

Low ankle brachial index (ABI) is a sensitive measure of 'burden' of atherosclerosis, indicating cardiovascular risk of the asymptomatic patient. Conventionally, ABI values <0.90 are considered pathological, indicating peripheral arterial disease. The purpose of this study was to establish whether GPs after a short training course can reliably determine ABI compared to assessment in a specialized hospital department. Epidemiological observational study. A total of 6 GPs and 12 general practice nurses from six practices were recruited for the study. Doppler measurements and ABI calculations were performed according to guidelines used by the Department of Nuclear Medicine, Odense University Hospital. On average, blood pressure measurements in general practice yielded lower values than those measured at the hospital. Differences in brachial and ankle blood pressure were -7 mmHg (-43 to 30 mmHg) and -14 mmHg (-63 to 33 mmHg), respectively. Sensitivity and specificity of ABI in general practice were 1.00 (0.87-1.00) and 0.79 (0.69-0.88), respectively. Predictive value of ABI measured <0.9 in general practice was 0.62 (0.46-0.76). Findings in general practice and at the Department of Nuclear Medicine were concordant with regard to the threshold value of ABI 0.9. However, this study does not warrant a recommendation of doppler measurements or assessment of ABI as screening or diagnostic procedure due to low specificity of assessments in general practice. Our results indicate a high number of false-positive tests if the method is applied for screening in general practice.

237 Similar prognostic abilities of different modes of calculation of the ankle-brachial index to predict mortality in patients with coronary artery disease. A systematic prospective study

The traditional method of calculation of the ankle-brachial index (ABI) and the usual 0.90 threshold have been recently challenged by alternate methods and values proposed as more sensitive to predict cardiovascular mortality. However the overall discriminative value of the ABI using different modes of calculation has not been systematically performed. We assessed the ABI to predict the 5-years mortality of 705 patients who underwent coronary bypass surgery. We compared the ROC curves of 6 modes of ABI calculation, combining 3 different numerators (the highest ( high ), the mean ( mean ) and the lowest ( low ) pressure of posterior tibial and anterior tibial arteries) with 2 denominators (the highest ( high ) or the mean ( mean ) systolic pressure of both arms). During follow-up, 97 (13.8%) patients died. The area under the curves (AUC) of the 6 methods to predict 5-years mortality were similar (Table). Only the AUC of method “ High/High ” was significantly (p<0.05) higher than method “ High/Mean ” and “Low/Mean”. The most accurate threshold to predict mortality differed for each method. Each mode of ABI calculation presents its own optimal cut-off value to predict mortality. The use of the single 0.90 threshold to compare different modes of ABI calculation is inappropriate. The ABI mode of calculation and the threshold should be considered altogether. The ability of the ABI to predict mortality is almost similar among different modes of calculation.

411: Inter-Rater Reliability and False Positive Result Rates of Ankle Brachial Index Measurements Performed by Emergency Providers

411: Inter-Rater Reliability and False Positive Result Rates of Ankle Brachial Index Measurements Performed by Emergency Providers

Ankle—brachial index performance among internal medicine residents

The ankle-brachial index (ABI) is the standard test used in clinical practice to detect peripheral artery disease (PAD) and is a powerful predictor of adverse cardiovascular outcomes. This study sought to measure the baseline knowledge of the ABI test among a sample of internal medicine residents and to examine the impact of an educational intervention on performance of the test. A total of 29 residents were asked to perform three tasks, with the performance of each task being assessed using a point-based scoring system: measure an ABI on a normal volunteer (15 points), calculate the ABI based on data from a hypothetical patient (3 points), and interpret a range of ABI values (6 points). A standardized educational intervention was then provided and post-education performance was assessed for each task using the same scoring system. At baseline, 4% of residents correctly measured the ABI, 10% correctly calculated the ABI, and 45% correctly interpreted the ABI. Baseline performance was unaffected by year of residency training. Following the educational intervention, 50% of residents correctly measured the ABI, 75% correctly calculated the ABI, and 88% correctly interpreted the ABI. The mean score for the tasks of ABI measurement, calculation and interpretation between baseline and post-education were 4.6 +/- 3 and 13.9 +/- 1.6 (p < 0.0001), 1 +/- 0.9 and 2.3 +/- 1.2 (p = 0.002), and 4.9 +/- 1.6 and 5.9 +/- 0.3 (p = 0.008), respectively. In conclusion, baseline knowledge of the ABI test was poor among a sample of internal medicine residents. These results suggest that instruction regarding the ABI test is deficient in medical school and residency programs and requires action by those responsible for the education of medical students and residents.

Índice Tornozelo-Braquial (ITB) determinado por esfigmomanômetros oscilométricos automáticos

Assessing Ankle-Brachial Index is an essential procedure in clinical settings, but since its measurement by the gold standard Doppler Ultrasonic (DU) technique is impaired by technical difficulties, it is underperformed.The aim of this study was to assess the efficacy of an automated oscillometric device (AOD) by performing Ankle-Brachial Index (ABI) assessments and to suggest delta brachial-brachial (delta-BB) and delta-ABI as markers of cardiovascular risk.In this observational and descriptive study, 247 patients (56.2% females, mean age 62.0 years) had their arterial blood pressure (ABP) measured for ABI calculation. Two AOD (OMRON-HEM705CP) devices were used for simultaneous measurements of the ABP, first of the two arms and then of the arm with higher systolic ABP and a leg, first the left and then the right one. When leg ABP measurements were not possible, ABI determination was performed by using the standard Doppler Ultrasonic (DU) technique. Patients were designated to Group N (normal ABI: 0.91 to 1.30) or Group A (abnormal ABI: < or =0.90 or >1.30). Other indexes were also calculated: delta-BB (absolute difference in mmHg of systolic ABP between arms) and delta-ABI (absolute difference of ABI between legs) and the results were compared.In most patients (90.7%), it was possible to determine the ABI. Group N data allowed calculation of the 95th percentile reference values (RV) of delta-BB (0 to 8 mmHg) and delta-ABI (0 to 0.13). When compared to Group N, Group A had a significantly higher prevalence of high values greater than the RVs of delta-ABI (30 of 52 and 10 of 195, respectively; Odds Ratio = 25.23; p<0.0001) and delta-BB (13 of 52 and 7 of 195, respectively; Odds Ratio = 8.95; p<0.0001).In most patients, the ABI could be measured by AOD. Both indexes, delta-BB and delta-ABI greater than the RVs, were significantly more prevalent in patients with abnormal ABI values, and their usefulness as new markers of cardiovascular disease should be further appraised in epidemiological studies.

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

BackgroundThe 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.MethodsIn 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.ResultsThe 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.ConclusionThe 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.

Lower ankle/brachial index, as calculated by averaging the dorsalis pedis and posterior tibial arterial pressures, and association with leg functioning in peripheral arterial disease

Objective: We compared three commonly used methods of ankle/brachial index (ABI) calculation to determine their relative association with objective measures of leg functioning in peripheral arterial disease. Method: The study design was cross-sectional; the setting was an academic medical center. The participants were 244 men and women, aged 55 years and older, with and without peripheral arterial disease, from a noninvasive vascular laboratory and a general medicine practice. The main outcome measures were walking velocity and endurance, measured with the 4-m walk and the 6-minute walk, respectively. Three methods of ABI calculation were assessed: using the highest arterial pressure within each leg (method #1), using the lowest pressure in each leg (method #2), and averaging the dorsalis pedis and posterior tibial pressures within each leg (method #3). For each method, we established the prevalence of peripheral arterial disease. We then used regression analyses to identify the ABI calculation method most closely associated with leg functioning. The ABI with the greatest statistical significance and largest regression coefficient was considered most closely associated with leg functioning. Results: Peripheral arterial disease prevalence ranged from 47% when method #1 was used to 59% when method #2 was used. When the right and left legs were compared, the leg with the lower ABI, as identified through use of method #3, was most associated with leg functioning. Within the leg with the lower ABI, method #3 was more closely associated with 6-minute walk distance (regression coefficient = 811.5 feet per 1 unit ABI; P <.001) and 4-m walking velocity (regression coefficient = 0.353 m/s per 1 unit ABI; P <.001) than method #1 or method #2. Conclusion: The lower ABI, determined by averaging the dorsalis pedis and posterior tibial arterial pressures in each leg, is most predictive of walking endurance and walking velocity in peripheral arterial disease. (J Vasc Surg 2000;32:1164-71.)