Ankle-brachial Index Threshold Research Articles

ANKLE-BRACHIAL INDEX AS SHORT TERM AND LONG-TERM PREDICTOR OF CARDIOVASCULAR EVENTS AFTER MYOCARDIAL INFARCTION: A 3-YEAR FOLLOW-UP STUDY

Objective: The ankle-brachial index (ABI) is a non-invasive index originally proposed for the diagnosis of lower-extremity peripheral artery disease. It is also a marker of atherosclerosis in other vascular sites and may serve as a prognostic marker for cardiovascular events even in the absence of PAD symptoms. However, data on the prognostic value of this index in the setting of acute myocardial infarction (MI) are scarce. Design and method: We prospectively evaluated 441 patients [79.4% male; average age 62 years, 67.6% hypertensive, 29.7% diabetes mellitus (DM); 54.9% STEMI] hospitalized for acute MI. Basic demographic, echocardiographic, peri- and postoperative details were recorded and analyzed. The ABI threshold used to define abnormal levels was less than or equal to 0.90 and recorded according to established guidelines using a certified automated device (ABPI MD, MESI®). The primary endpoint was a composite of all-cause and cardiovascular death, as well as major cardiovascular events including decompensated heart failure, new ACS, cerebrovascular event, malignant arrhythmia, PAD event and new onset renal dysfunction. All events were assessed both in-hospital and within 3 years of follow-up. Results: The mean ABI of our study population was estimated to be 1.1 (IQR: 1.00 to 1.18). In reduced multivariate regression models ABI was a prognostic indicator for the in-hospital composite endpoint. Particularly, patients with abnormal ABI showed a threefold risk of in-hospital events [HR 2.93, 95% CI: 1.48-5.81, p=0.002]. Regarding all-cause mortality, after multivariate analysis, ABI [HR 2.88, 95% CI: 1.53 – 5.42, p=0.001] maintained its predictive power regardless of hypertension, DM, LDL levels and smoking status of the study population in 3 years follow-up. Conclusions: In the setting of an acute MI, lower ABI values expose these patients to a higher risk of in-hospital events and are independently associated with long-term all-cause mortality. Consequently, ABI monitoring in patients with MI may identify patients with a higher risk profile and contribute to early clinical decision making.

Performance of systolic pressure index for lower limb peripheral arterial disease in a group of elderly in sub-Saharan Africa

BackgroundThe automatic measurement of the ankle-brachial index (ABI) constitutes a reliable, simple, safe, rapid, and inexpensive alternative diagnostic screening test compared with the Doppler method for peripheral arterial disease (PAD). We aimed to compare the diagnostic performance of automatic ABI measurement tests to Doppler ultrasound for PAD in a group of patients aged 65 years and above, in Sub-Saharan Africa. MethodsThis was an experimental comparative study of the performance of Doppler ultrasound to the automated ABI test in the diagnosis of PAD in patients aged ≥ 65 years followed-up at the Yaoundé Central Hospital, Cameroon between January to June 2018. An ABI threshold < 0.90 is defined as a PAD. We compare the sensitivity, and specificity of the high ankle-brachial index (ABI-HIGH), low ankle-brachial index (ABI-LOW), and the mean ankle-brachial index (ABI-MEAN) for both tests. ResultsWe included 137 subjects with an average age of 71.7 ± 6.8 years. In the ABI-HIGH mode, the automatic device had a sensitivity of 55% and a specificity of 98.35% with a difference between the two techniques of d = 0.024 (p = 0.016). In the ABI-MEAN mode, it had a sensitivity of 40.63% and a specificity of 99.15%; d = 0.071 (p < 0.0001). In the ABI-LOW mode, it had a sensitivity of 30.95% and a specificity of 99.11%; d = 0.119 (p < 0.0001). ConclusionThe Automatic measurement of systolic pressure index has a better diagnostic performance in the detection of Peripheral Arterial Disease compared to the reference method by continuous Doppler in sub-Saharan African subjects aged ≥ 65 years.

A Re-evaluation of the Current Ankle-Brachial Index Threshold in the Setting of Trauma

INTRODUCTION: An ankle-brachial index (ABI) less than 0.9 is the current threshold for determining need for CT angiogram in a trauma patient without hard signs of vascular injury. Recent work suggests a screening threshold of 0.7 may be used without missing an injury. We hypothesized that a threshold of 0.7 would lead to missed injuries. METHODS: Retrospective review during a 44-month period identified patients 15 years and older with traumatic injury, recorded ABI, and CT angiogram of an extremity. Sensitivity and specificity were calculated for radiographic abnormality and major vascular injury requiring intervention at various ABI thresholds. Analyses were performed for all-cause traumatic injury, blunt, and penetrating mechanisms. RESULTS: A total of 319 patients met inclusion criteria. Penetrating injury was the predominant mechanism (63%). Of the patients who had a radiographic abnormality on CTA (33%), 7.6% required procedural intervention. All patients undergoing intervention had a soft sign of vascular injury at time of presentation: penetrating injury adjacent to major vascular structure (n = 7), history of arterial bleeding (n = 3), or nonexpanding hematoma (n = 3). An ABI of 0.7 had a sensitivity of 33.3% for detecting vascular injuries requiring intervention. Sensitivity was poor even for the standard ABI threshold of 0.9 (66.7%; Table). Table. - Sensitivity and Specificity Analyses for Various Ankle-Brachial Index Thresholds Outcome Ankle-Brachial Index ≤ 0.9 Ankle-Brachial Index ≤ 0.8 Ankle-Brachial Index ≤ 0.7 Major vascular injury requiring intervention All-cause Sensitivity = 66.7% Specificity = 49.5% Sensitivity = 44.4% Specificity = 78.2% Sensitivity = 33.3% Specificity = 87.8% Penetrating Sensitivity = 66.7% Specificity = 49.7% Sensitivity = 44.4% Specificity = 80.0% Sensitivity = 33.3% Specificity = 90.3% Radiographic Irregularity All-cause Sensitivity = 56.3% Specificity = 53.7% Sensitivity = 31.1% Specificity = 82.8% Sensitivity = 19.4% Specificity = 91.1% Penetrating Sensitivity = 62.9% Specificity = 54.9% Sensitivity = 32.3% Specificity = 84.4% Sensitivity = 19.4% Specificity = 93.4% Blunt Sensitivity = 46.3% Specificity = 51.9% Sensitivity = 29.3% Specificity = 80.2% Sensitivity = 19.5% Specificity = 87.7% CONCLUSION: ABI alone proved to be a poor screening test for vascular injury in this cohort of patients, which represents the highest rate of penetrating trauma in any study evaluating ABI. These results invite a re-evaluation of ABI’s usefulness in modern trauma assessments because a subset of clinically significant vascular injuries may go undetected by the current threshold.

An assessment of a screening method for peripheral arterial disease of the lower limbs in patients aged at least 65 years at the Yaoundé Central Hospital, Cameroon

The automatic measurement of the Ankle-Brachial Index (ABI) constitutes a reliable, simple, safe, rapid, and inexpensive alternative diagnostic screening test compared with the Doppler method for peripheral arterial disease (PAD). We aimed to compare the diagnostic performance of automatic ABI measurement tests to Doppler ultrasound for PAD in patients aged ≥ 65. This was an experimental comparative study of Doppler ultrasound's performance to the automated ABI test in diagnosing PAD in patients aged ≥ 65 years followed up at the Yaoundé Central Hospital, Cameroon, between January to June 2018. An ABI threshold < 0.90 defined a PAD. We compare the sensitivity, and specificity of the high Ankle-Brachial Index (ABI-HIGH), low Ankle-Brachial Index (ABI-LOW), and the mean Ankle-Brachial Index (ABI-MEAN) for both tests. We included 137 subjects with an average age of 71.7 ± 6.8 years. In the ABI-HIGH mode, the automatic device had a sensitivity of 55% and a specificity of 98.35% with a difference between the two techniques of d = 0.024 ( P = 0.016). In the ABI-MEAN mode, it had a sensitivity of 40.63% and a specificity of 99.15%; d = 0.071 ( P < 0.0001). In the ABI-LOW mode, it had a sensitivity of 30.95% and a specificity of 99.11%; d = 0.119 ( P < 0.0001). Compared to the Doppler method, the ABI-HIGH mode of the automatic measuring device had better diagnostic performance and can thus be used as a screening test for PAD patients aged ≥ 65 years in our context.

Ankle-Brachial Index for Risk Stratification in Patients With Symptomatic Peripheral Artery Disease With and Without Prior Lower Extremity Revascularization: Observations From the EUCLID Trial.

[Figure: see text].

Re-evaluating the safety and effectiveness of the 0.9 ankle-brachial index threshold in penetrating lower extremity trauma

ObjectiveCurrent guidelines recommend additional imaging when the ankle-brachial index (ABI) is ≤0.9 after extremity trauma; however, the accuracy of this 0.9 threshold compared with other values has not been evaluated. The primary aim of this study was to compare the safety and effectiveness of various ABI thresholds in predicting lower extremity vascular injuries after penetrating trauma. We hypothesized that a lower ABI threshold can be used safely to avoid unnecessary imaging. MethodsA retrospective cohort study was performed at a single level I trauma center from January 2015 to December 2017. All patients who presented with penetrating lower extremity trauma and who underwent computed tomography angiography (CTA) were reviewed. Patients taken directly to the operating room without first undergoing CTA or those without documented ABIs were excluded. Demographic information, clinical features of presentation, interventions performed, and outcomes were recorded. P values were obtained using the Kolmogorov-Smirnov test, and a receiver operating characteristic curve was created to compare various ABI thresholds. ResultsA total of 47 patients (81% male), with a mean age of 29 years (range, 14-59 years), met inclusion criteria. Of the 17 limbs (36%) with a vascular abnormality seen on CTA, 6 (35%) required an intervention. The distribution of ABIs in injured limbs requiring revascularization was significantly lower (P = .006) than in those that did not require intervention. An ABI threshold of 0.7 is most accurate, with the highest combined sensitivity (83%) and specificity (91%) for detecting vascular injuries requiring revascularization. In addition, the negative predictive value was no different between a threshold of 0.7 (98%) and a threshold of 0.9 (97%), with both thresholds missing one vascular injury (pseudoaneurysm) requiring repair. ConclusionsThe ABI remains reliable in distinguishing between limbs with and limbs without vascular injury requiring revascularization after penetrating lower extremity trauma. A lower threshold can safely be used without compromising the negative predictive value of a screening ABI. Applying a threshold of 0.7 to our cohort would have avoided 51% (24) of the CTA studies performed without missing additional vascular injuries requiring repair.

Re-evaluating the Safety and Effectiveness of the 0..9 Ankle-Brachial Index Threshold in Penetrating Lower Extremity Trauma

Re-evaluating the Safety and Effectiveness of the 0..9 Ankle-Brachial Index Threshold in Penetrating Lower Extremity Trauma

Lowering the Ankle–Brachial Index Threshold in Blunt Lower Extremity Trauma May Prevent Unnecessary Imaging

Current algorithms for the management of blunt lower extremity trauma recommend additional imaging in patients presenting with soft signs of vascular injury and an ankle-brachial index (ABI) less than 0.9. The aim of this study is to analyze lower extremity computed tomography angiographies (CTAs) to determine the incidence and characteristics of patients sustaining vascular injury from blunt lower extremity trauma. We hypothesized that a lower ABI threshold can avoid unnecessary imaging without missing clinically significant vascular injury. A single-center, retrospective review of all consecutive patients who presented to a level 1 trauma center with blunt lower extremity trauma and underwent a CTA from January 2015 to December 2017 was conducted. Baseline demographics, clinical features, and outcomes were recorded. Patients without documented ABIs were excluded. A receiver operating characteristic curve was used to define the ABI threshold. One hundred twenty-five patients (133 injured limbs) met inclusion criteria. The mean age was 44years (range 9-96), and 74% of the patients were male. A vascular abnormality was identified on CTA in 65 limbs (48.9%), of which only 8 (12%) required intervention. The ABIs in these 8 injured limbs were between 0 and 0.6. An ABI threshold of 0.6 maximized the balance between sensitivity (100%) and specificity (87%) and missed no injuries requiring revascularization. The ABI remains useful in evaluating blunt lower extremity trauma. A lower ABI threshold in patients presenting with soft signs of vascular injury after blunt trauma may avoid unnecessary imaging without missing vascular injuries requiring intervention. Further prospective studies are needed to validate the safety and effectiveness of a lower ABI threshold.

Lowering the Ankle Brachial Index Threshold in Blunt Lower Extremity Trauma May Prevent Unnecessary Imaging

Lowering the Ankle Brachial Index Threshold in Blunt Lower Extremity Trauma May Prevent Unnecessary Imaging

Effects of the whole nursing intervention on the control of the risk factors of diabetic foot

Objective To investigate the effects of the whole nursing intervention on the control of the risk factors of diabetic foot. Methods A total of 600 cases of type 2 diabetes patients with the risk factors of diabetic foot were randomly divided into observation group and control group, 300 respectively. For each group, there were three subgroups of low, medium and high risk of diabetic foot with 100 cases in each subgroup. Patients in two groups were given the whole nursing intervention and routine nursing intervention respectively. The foot skin conditions, ankle brachial index (ABI) and sensory threshold determination, weighted integral score of risk factors of diabetic foot and the incidence of diabetic foot before the intervention, 6 months post intervention, 12 months post intervention and 18 months post intervention were compared between two groups. Results Before the intervention, there were no statistically significant differences in the foot skin conditions, determination of ABI and sensory threshold, weighted integral score of risk factors of diabetic foot and the incidence of diabetic foot between two groups (P>0.05) . At 6 months post intervention, 12 months post intervention and 18 months post intervention, significant differences in the foot skin conditions were observed between two groups (P 0.05) . At 12 and 18 months post intervention, there were statistically significant differences in the ABI and sensory threshold value between two groups (P<0.05) . At 18 months post intervention, comparison of weighted integral scores of risk factors of diabetic foot between two groups showed that, in the observation group, the ratio of subgroup with low-risk increased, while the ratios of subgroups with medium and high-risk decreased; in the control group, the ratio of subgroup with low-risk decreased, while the ratios of subgroups with medium and high-risk increased. The differences were statistically significant (P<0.01) . There were 10 cases of diabetic foot in the observation group and 38 cases in the control group. The number of diabetic foots in the observation group was significantly lower than that in the control group, with a statistically significant difference (P<0.01) . Conclusions The effect of the whole nursing intervention on the control of the risk factors of diabetic foot is remarkable. Key words: Diabetic foot; Risk factor; Nursing intervention

Ankle brachial index for the diagnosis of lower limb peripheral arterial disease.

Ankle brachial index for the diagnosis of lower limb peripheral arterial disease.

Effectiveness of bedside investigations to diagnose peripheral artery disease among people with diabetes mellitus: a systematic review.

Non-invasive tests for the detection of peripheral artery disease (PAD) among individuals with diabetes mellitus are important to estimate the risk of amputation, ulceration, wound healing and the presence of cardiovascular disease, yet there are no consensus recommendations to support a particular diagnostic modality over another and to evaluate the performance of index non-invasive diagnostic tests against reference standard imaging techniques (magnetic resonance angiography, computed tomography angiography, digital subtraction angiography and colour duplex ultrasound) for the detection of PAD among patients with diabetes. Two reviewers independently screened potential studies for inclusion and extracted study data. Eligible studies evaluated an index test for PAD against a reference test. An assessment of methodological quality was performed using the quality assessment for diagnostic accuracy studies instrument. Of the 6629 studies identified, ten met the criteria for inclusion. In these studies, the patients had a median age of 60-74 years and a median duration of diabetes of 9-24 years. Two studies reported exclusively on patients with symptomatic (ulcerated/infected) feet, two on patients with asymptomatic (intact) feet only, and the remaining six on patients both with and without foot ulceration. Ankle brachial index (ABI) was the most widely assessed index test. Overall, the positive likelihood ratio and negative likelihood ratio (NLR) of an ABI threshold <0.9 ranged from 2 to 25 (median 8) and <0.1 to 0.7 (median 0.3), respectively. In patients with neuropathy, the NLR of the ABI was generally higher (two out of three studies), indicating poorer performance, and ranged between 0.3 and 0.5. A toe brachial index <0.75 was associated with a median positive likelihood ratio and NLRs of 3 and ≤ 0.1, respectively, and was less affected by neuropathy in one study. Also, in two separate studies, pulse oximetry used to measure the oxygen saturation of peripheral blood and Doppler wave form analyses had NLRs of 0.2 and <0.1. The reported performance of ABI for the diagnosis of PAD in patients with diabetes mellitus is variable and is adversely affected by the presence of neuropathy. Limited evidence suggests that toe brachial index, pulse oximetry and wave form analysis may be superior to ABI for diagnosing PAD in patients with neuropathy with and without foot ulcers. There were insufficient data to support the adoption of one particular diagnostic modality over another and no comparisons existed with clinical examination. The quality of studies evaluating diagnostic techniques for the detection of PAD in individuals with diabetes is poor. Improved compliance with guidelines for methodological quality is needed in future studies.

270 Determination of the best ankle brachial index threshold values to efficiently detect significant lower limb arterial plaques using an automated device in a population with risk factors

270 Determination of the best ankle brachial index threshold values to efficiently detect significant lower limb arterial plaques using an automated device in a population with risk factors

Ankle–brachial index and cardiovascular risk prediction: An analysis of 11,594 individuals with 10-year follow-up

BackgroundLow ankle–brachial index (ABI) is associated with increased risk of subsequent cardiovascular disease events, independent of Framingham risk factors, but its ability to improve risk prediction prospectively has not been examined. MethodsWe conducted post-hoc analysis of data from Atherosclerosis Risk in Communities Study (ARIC Study), a large prospective cohort study. 11,594 white and African American (24.2%) men and women, aged 45–64 years, with available Framingham Risk Score (FRS) variables and ABIs at baseline, and without known history of cardiovascular disease or diabetes mellitus or known peripheral arterial disease at baseline were assessed for hard cardiovascular events (hCVD; defined as heart attack, coronary death or stroke) over median follow-up of 10 years. Hazard ratios, C statistic, and net reclassification indexes were calculated to determine the independent predictive ability of ABI compared with FRS. Results659 hCVD events occurred. Standardized ABI was significantly associated with hCVD events but with a relatively small effect on events (hazard ratios of 0.85 per standard deviation (95% CI 0.79–0.91) (p-value<0.0001)). The C statistic of FRS modified with ABI was only modestly improved (0.756–0.758). Net reclassification improvement, an indicator of prospective prediction performance, using an ABI threshold of 0.9 was small and statistically insignificant (0.8%, p=0.50). ConclusionsAlthough the ABI adjusted for Framingham risk variables was independently associated with subsequent events in terms of hazard ratios, the independent effect of ABI when adjusted for FRS was small in magnitude, and the FRS performed similarly with or without integration or supplementation with ABI. These findings do not provide strong evidence to support FRS modification to include ABI.

Artériopathie oblitérante des membres inférieurs chez la femme

The widespread use of the ankle-brachial index (ABI) enabled to reveal the high prevalence of lower extremities peripheral arterial disease (PAD) in women, even higher than in men in several series. Nonetheless, the use of a same ABI threshold for men and women may overestimate the prevalence of subclinical PAD in women. Conversely, the clinical manifestations of PAD are more often atypical in women, with as a result, a delayed diagnosis and management. The level of association between cardiovascular disease risk factors and PAD is similar in both genders. To date, there is no evidence for any association between PAD and different hormonal events in women. Despite an inverse association between hormonal replacement therapy (HRT) after menopause and PAD in epidemiological studies, the trials failed to evidence any protective effect of HRT to prevent PAD. Women with PAD are advised to discontinue HRT in case of limb revascularization. The long-term local and functional prognosis of PAD seems more severe in women, but this is partly explained by a delayed onset of the disease, occurring at a later age. Similarly, the general cardiovascular prognosis PAD is also poorer in women than in men.

Prevalence and Risk Factors of PAD among Patients with Elevated ABI

To assess the prevalence and clinical significance of elevated ankle-brachial index (ABI) in patients referred to vascular consultation. Retrospective clinical study. In 1,762 patients referred with a suspicion of peripheral arterial disease (PAD), ABI and toe brachial index (TBI) were measured by photoplethysmography. ABI>/=1.3 was considered falsely elevated and TBI<0.60 was the diagnostic criterion for PAD. The prevalence of elevated ABI was 8.4% and that of PAD among these patients 62.2%. PAD was significantly more prevalent among subjects with severe symptoms (rest pain, ulcers or gangrene) than in those with intermittent claudication (83.8% and 45.3%, respectively, p<0.001). The risk of PAD diagnosis was ten-fold (OR 10.31, 95% CI 2.07-51.30) among those with chronic renal failure, five-fold among patients with a history of smoking (OR 5.63, 95% CI 1.22-26.00) and over three-fold (OR 3.44, 95% CI 1.46-8.12) among those with coronary heart disease. The specificities of elevated ABI threshold levels (1.3, 1.4 and 1.5) in identifying PAD were 86%, 94% and 96%, respectively, the sensitivities being 44%, 38% and 36%, respectively. The prevalence of elevated ABI in patients referred to vascular consultation is 8.4% and that of PAD among these 62.2%. PAD is significantly more probable among those with chronic renal failure, a history of smoking and coronary heart disease. Furthermore, the specificity of elevated ABI (>/=1.3) in recognizing PAD is good, whereas the sensitivity is only satisfactory.

Intrinsic contribution of gender and ethnicity to normal ankle-brachial index values: The Multi-Ethnic Study of Atherosclerosis (MESA)

Several studies report a higher prevalence of peripheral arterial disease (PAD) in women and among blacks. These studies based their PAD definition on an ankle-brachial index (ABI) <0.90. We hypothesized that there is an inherent contribution of gender and ethnicity to normal ABI values, independent of biologic and social disparities that exist between gender and ethnic groups. Consequently, an ABI threshold that disregards these fundamental gender-related and ethnicity-related differences could partly contribute to reported prevalence differences. A cross-sectional study was designed as part of the Multi-Ethnic Study of Atherosclerosis (MESA), a multicenter United States population study. We selected a subgroup of participants with unequivocally normal ABIs (1.00 to 1.30), and additionally excluded participants with any major PAD risk factor (smoking, diabetes, dyslipidemia, hypertension). In a linear model with ABI as the dependent variable, demographic, clinical, biologic, and social variables were introduced as independent factors. Among 1775 healthy participants, there was no association between ABI level and subclinical cardiovascular disease (coronary calcium or carotid plaque). Male gender, weight, and high education level were positively correlated with ABI, whereas black race, triglycerides, pack-years (in past smokers), and pulse pressure were negatively correlated. In the fully adjusted model, women had about 0.02 lower ABI values than men, and blacks showed ABI values about 0.02 lower than non-Hispanic whites. These data suggest intrinsic ethnic and gender differences in ABI. Such differences, although small in magnitude, are highly significant and can distort population estimates of disease burden.