Ankle brachial index measurement in primary care: are we doing it right?

Tibiofemoral Dislocation Management in a Rural High School Football Scenario: Development of a Popliteal Artery Injury Suspicion Index

OBJECTIVE

This study evaluated the knowledge and preparedness of athletic trainers (ATs) for diagnosing and managing an anterior tibiofemoral knee dislocation in a rural or limited-resource high school football setting scenario. The study hypothesis was that more experienced ATs would display greater preparedness than less experienced ATs. A secondary objective was to develop evidence-based guidelines to help the AT provide better emergency triage care.

METHODS

This prospective cross-sectional study distributed a rural high school football game scenario survey electronically to a random sample of 2000 certified ATs to determine their perceptions of readiness to diagnose and manage an anterior tibiofemoral knee dislocation with signs or symptoms of possible popliteal artery injury.

RESULTS

A total of 249 surveys (12.5%) were completed. Years of athletic training experience were ≤5 years (n = 82, group 1) and ≥6 years (n = 167, group 2). Both groups perceived that they could not "rule out" an arterial injury and had similar "red flag" sign and symptom rankings. Group 2 perceived a more serious situation than group 1 (77.5 ± 15 vs 70.8 ± 14, P < 0.0001) and were more likely to activate the emergency action plan (74.5 ± 25 vs 64.4 ± 26, P = 0.005). Both groups were "neutral" about their ability to diagnose the condition or manage the case, had poor ankle-brachial index test familiarity, and agreed that evidence-based guidance was needed.

CONCLUSIONS

More experienced ATs perceived a more serious situation than less experienced ATs and were more likely to activate the emergency action plan. Both groups were neutral about their ability to diagnose the condition or manage the case, had poor ankle-brachial index test familiarity, and agreed that they would benefit from evidence-based guidance. Proposed guidelines provide the AT with a more measured, evidence-based index of suspicion for potential popliteal artery injury in anterior tibiofemoral dislocation cases. This will complement existing hospital emergency department-based management algorithms, decreasing the likelihood of this condition progressing to limb loss or death.

Ankle brachial index and its correlation with cardiovascular risk factors in pre-diabetes: Two-year cross-sectional study

Background

A state of impaired glucose tolerance is called prediabetes. The diagnosis of prediabetes is controversial, yet it still puts a person at risk for developing diabetes. The ankle-brachial index (ABI) is useful for identifying persons at risk for peripheral artery disease and for diagnosing the condition in those who have symptoms in their lower extremities and subclinical atherosclerosis. This study highlights ABI and its correlation with cardiovascular risk factors like lipid profile and anthropometric measurement including neck circumference in prediabetes so that primary care physicians may be able to diagnose early before advancing to diabetes.

Materials and Methods

This cross-sectional study of 2 years duration from December 2020 to September 2022 was conducted in the Department of Medicine, at a tertiary care teaching hospital situated in a rural area. Patients with pre-diabetes were enrolled and Ankle Brachial Index was calculated. The correlation of ABI with anthropometric measures and lipid profile was assessed.

Results

On calculating ABI by manual method 21% which is 42 out of 200 had low ABI (<0.9). On the other hand, on calculating ABI by probe method low range of ABI was found to be 37% which is 74 patients out of 200. There was a significant correlation between ABI and body mass index and lipid profile. The diagnostic performance of ABI < 0.9 had 56.8% sensitivity and 100.0% specificity.

Conclusion

ABI can be used as a noninvasive and cost-effective modality for assessing subclinical atherosclerosis in patients with prediabetes and thus prevent its morbid complications even assessed at the primary care physician level.

Diagnostic values of ischemia modified albumin in diabetes-related complications: a narrative review

Purpose

Oxidative stress (OS) plays a critical role in the onset and progression of macro and microvascular complications of diabetes mellitus (DM). Ischemia-modified albumin (IMA) is a novel and simple test for evaluating OS. In the present study, we reviewed the available information on the alteration of circulating IMA in DM and its possible prognostic and diagnostic value in DM-related complications.

Methods

Relevant studies regarding IMA alteration in DM published until May 30, 2022 were extracted from Google Scholar, PubMed, Scopus, and Science Direct databases. The following key words were used: IMA, DM, diabetes complications, retinopathy, nephropathy, diabetic foot, and vascular complications.

Results

This review revealed increased circulating IMA levels in the patients with type 1, type 2, and gestational DM. Furthermore, IMA showed a close relationship with the severity of DM complications including hyperglycemia, dyslipidemia, diabetic retinopathy, diabetic nephropathy, peripheral arterial disease, and diabetic foot ulcer. However, lack of assay standardization and low specificity are major obstacles to the use of IMA as a promising biomarker.

Conclusion

IMA levels are associated with DM complications and can be applied as a practical test for evaluating the risk and predicting the severity of DM complications.

Validating fatty acid binding protein 3 as a diagnostic and prognostic biomarker for peripheral arterial disease: A three-year prospective follow-up study

BACKGROUND

Patients with peripheral arterial disease (PAD) often remain undiagnosed and therefore suboptimally managed. Here, we investigated the diagnostic and prognostic potential of fatty acid binding protein 3 (FABP3) in patients with PAD.

METHODS

In the discovery phase, 374 PAD and 184 non-PAD patients were recruited from vascular surgery ambulatory clinics at St. Michael's Hospital (Toronto, Ontario, Canada) between October 4, 2017 to October 29, 2018. The diagnostic ability of baseline FABP3 level was investigated through receiver operator characteristic (ROC) curves to determine two cutoff points: 1) an exclusionary "rule out" cutoff point, and 2) a confirmatory "rule in" cutoff point. Next, these cutoff points were confirmed in the external validation phase using a separate cohort of 312 patients (180 PAD and 132 non-PAD) recruited from ambulatory vascular surgery clinics at St. Michael's Hospital (Canada) between November 6, 2018-July 30, 2019. Cox regression analyses were used to explore the independent association between FABP3 and major adverse limb events (MALE - defined as need for arterial revascularization or major amputation) and decrease in ankle-brachial index (ABI -defined as drop ≥0.15) during 3 years of follow-up.

FINDINGS

In the discovery phase, FABP3 levels were significantly elevated in patients with PAD compared to non-PAD patients. ROC analysis demonstrated that FABP3 had an AUC of 0.83 (95% CI: 0.81-0.86, p-value < 0.001). FABP3 exclusionary cutoff was <1.55 ng/ml (sensitivity = 96%; specificity = 40%), whereas FABP3 confirmatory cutoff was >3.55 ng/ml (sensitivity = 43%; specificity = 95%) - values that were confirmed in the external validation phase. Cox regression analysis demonstrated FABP3 to be an independent predictor of increase in MALE [HR = 1.14 (1.03-1.29); p-value = 0.010] and worsening PAD status (drop in ABI >0.15 [HR = 1.11 (1.02-1.19); p-value = 0.009]).

INTERPRETATION

Our findings suggested that FABP3 levels can be used as both a diagnostic and prognostic biomarker for PAD, and may facilitate risk stratification in select individuals for purposes of vascular evaluation or intensive medical management.

FUNDING

Funding for this study was provided by the Bill and Vicky Blair Foundation.

Diagnostic Accuracy of Ankle-Brachial Pressure Index Compared with Doppler Arterial Waveforms for Detecting Peripheral Arterial Disease: A Systematic Review

GENERAL PURPOSE

To present the results of a research study evaluating the diagnostic accuracy of the ankle-brachial pressure index (ABPI) compared with that of Doppler arterial waveforms (DAWs) to detect peripheral arterial disease (PAD).

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After completing this continuing education activity, the participant will:1. Summarize the evidence the authors considered when comparing the diagnostic accuracy of the ABPI with that of Doppler arterial waveforms to detect PAD.2. Select the characteristics of the participants in the studies the authors analyzed.3. Identify the results of the authors' study comparing the diagnostic accuracy of the ABPI with that of Doppler arterial waveforms to detect PAD.4. Distinguish the authors' conclusions about the advantages of using Doppler arterial waveforms to detect PAD.

Perceptions of primary care and hospital clinicians on the use of the Ankle Brachial Pressure Index in general practice

INTRODUCTION Peripheral arterial disease is an increasingly prevalent chronic illness globally. The Ankle Brachial Pressure Index (ABPI) is a well-established, simple, relatively quick and non-invasive assessment useful in diagnosing and quantifying peripheral arterial disease. ABPIs may be currently underutilised in general practice. AIM To explore perspectives of health professionals on the role of the ABPI. METHODS One-to-one interviews were conducted with health professionals using snowball sampling. Questions centred around interviewees' education on, experience with and view on the usefulness of the ABPI in general practice. Interviews were recorded and used for thematic analysis. RESULTS Participants consisted of 13 health-care professionals: nine general practitioners, two vascular surgeons and two allied health professionals. Most general practitioners interviewed identified benefits of ABPIs use in primary care, including aiding peripheral arterial disease diagnostics, management, referral and triage. No general practitioners stated they had ever had formal training in undertaking ABPIs. Two of the nine general practitioners stated regular ABPI use in their practice. Participants who did not use ABPIs identified practical barriers to its use in general practice, including cost of equipment, length of time needed and perceived low patient need to justify cost. All interviewees agreed that there was a role for ABPI use in the community if barriers were overcome. DISCUSSION There was consensus among general practitioners that ABPI use is beneficial. Many general practitioners named similar practical barriers to more common use of ABPIs in general practice. They saw a role for ABPIs in primary care, although it may be more practical as a tool for specialised individual clinicians to use for communities, given practical barriers of cost, time and perceived low patient need. Formal training could be considered, as none of the interviewed general practitioners had ever had any.

Fatty acid binding protein 3 is associated with peripheral arterial disease

Background

Peripheral arterial disease (PAD) affects more than 150 million people worldwide and is associated with high rates of lower extremity amputation, myocardial infarction, stroke and death. Fatty acid binding protein 3 (FABP3) is released into circulation in patients with skeletal muscle injury. In this pilot study, we investigated a possible association between PAD and blood levels of FABP3.

Methods

Blood samples were collected from patients with clinical symptoms and diagnostic findings indicative of PAD (PAD group; ankle-brachial index [ABI] <0.9; n = 75) and in those without clinical or diagnostic features of PAD (non-PAD group; ABI >0.9; n = 75) presenting to vascular surgery ambulatory clinics at St. Michael's Hospital. Plasma samples were analyzed by protein multiplex to quantify FABP3 levels.

Results

PAD patients were found to have higher blood levels of FABP3 compared to patients without PAD (mean 3.90 ± 1.69 vs 2.03 ± 0.78; P < .001). A subgroup analysis demonstrated that the FABP3 levels were increased by almost two-fold in patients with PAD, independent of coronary artery disease (P < .001) or diabetes mellitus status (P < .001). Moreover, a significant negative correlation between FABP3 and the ABI was observed in PAD and patients without PAD matched groups (r = –0.51; P = .001). Last, immunohistochemistry demonstrated elevated expressions of FABP3 within skeletal muscle obtained from patients with the most severe form of PAD, chronic limb-threatening ischemia, when compared with patients without PAD.

Conclusions

Patients with PAD have elevated plasma levels of FABP3. An increasing severity of PAD is associated with higher FABP3 levels.

There is a pressing need for a simple, readily accessible, blood-based biomarker for PAD. In this study, we found elevated levels of FABP3 in patients with PAD. This increase in FABP3 was irrespective of history of coronary artery disease or diabetes. Furthermore, our data suggest that an increasing severity of PAD is associated with higher FABP3 levels. Subsequently, FABP3 may be a potential diagnostic biomarker for PAD. However, further studies are needed to confirm the capability of FABP3 to serve as a valid and reliable biomarker for PAD.

Perceived Challenges to Routine Uptake of the Ankle Brachial Index within Primary Care Practice

(1) Introduction: The ankle-brachial index (ABI) is the most widely used method of diagnosing peripheral arterial disease (PAD). However, the uptake of ABIs has been reported to be low in primary care settings across different various healthcare settings; however, this is yet to be investigated within the Canadian context. (2) Objective: Therefore, we sought to assess the rates of ABI usage as well as perceived barriers among primary care practitioners (PCPs) in Toronto, Canada. (3) Methods: A modified questionnaire was electronically sent to 257 PCPs in the Greater Toronto Area (GTA). Questions pertained to frequency, feasibility, utility, and barriers associated with ABI usage in clinical practice. Responses were collected and tallied. (4) Results: A total of 52 PCPs completed the questionnaire. 79% of PCPs did not routinely perform ABIs within their clinical practice, and 56% deemed ABI usage as unfeasible. Constraints in time and staff personnel, as well as complexity of ABI result interpretation, were cited as the major perceived barriers to ABI usage. The overwhelming majority of PCPs viewed alternative forms of diagnosis, such as a blood test for PAD, as being preferable to ABI, as such an approach would enhance diagnostic simplicity and efficiency. (5) Conclusion: ABI usage rates are poor within primary care practices in Toronto, Canada. Alternative approaches for diagnosing PAD may result in greater adoption rates among PCPs and therefore improve the identification of patients with PAD.

Clinical factors associated with peripheral artery disease in patients with documented coronary artery disease: A post hoc analysis of the COMPASS trial

BACKGROUND AND AIMS

Patients with coronary artery disease (CAD) who also have peripheral artery disease (PAD) are at high risk of subsequent cardiovascular events and mortality. Despite this, PAD in patients with CAD often remains undiagnosed. The objective of this analysis was to assess clinical factors that predict the presence of PAD in patient with documented CAD who also have PAD.

METHODS

In a post hoc analysis of patients with CAD in the COMPASS trial, we developed separate prediction models for symptomatic lower extremity PAD and documented carotid artery disease (Model 1), asymptomatic lower extremity PAD defined as ABI <0.9 (Model 2) and for any PAD (symptomatic or asymptomatic; Model 3). Using logistic regression models, candidate variables were chosen to predict the presence of PAD. Overall model performance was evaluated for discrimination and calibration using the concordance statistic and Hosmer and Lemeshow Goodness-of-fit chi-square, respectively. The final model was validated by bootstrapping.

RESULTS

Of 23,402 participants, 3484 (14.9%) had a history of symptomatic PAD or carotid artery disease (Model 1), 1422 (5.7%) participants had asymptomatic PAD (Model 2) and 4906 (20.6%) had any PAD (Model 3). Model 1 demonstrated a C-statistic of 0.667 and goodness-of-fit p-value of 0.859. Model 2 demonstrated a C-statistic of 0.626 and goodness-of-fit p-value of 0.250. Model 3 demonstrated a C-statistic of 0.646 and goodness-of-fit p-value of 0.240.

CONCLUSION

Routinely available clinical information is only marginally useful to identify patients with CAD and concomitant PAD.

Urinary fatty acid binding protein 3 (uFABP3) is a potential biomarker for peripheral arterial disease

Plasma levels of fatty acid binding protein 3 (pFABP3) are elevated in patients with peripheral artery disease (PAD). Since the kidney filters FABP3 from circulation, we investigated whether urinary fatty acid binding protein 3 (uFABP3) is associated with PAD, and also explored its potential as a diagnostic biomarker for this disease state. A total of 130 patients were recruited from outpatient clinics at St. Michael's Hospital, comprising of 65 patients with PAD and 65 patients without PAD (non-PAD). Levels of uFABP3 normalized for urine creatinine (uFABP3/uCr) were 1.7-folds higher in patients with PAD [median (IQR) 4.41 (2.79-8.08)] compared with non-PAD controls [median (IQR) 2.49 (1.78-3.12), p-value = 0.001]. Subgroup analysis demonstrated no significant effect of cardiovascular risk factors (age, sex, hypertension, hypercholesteremia, diabetes and smoking) on uFABP3/uCr in both PAD and non-PAD patients. Spearmen correlation studies demonstrated a significant negative correlation between uFABP3/uCr and ABI (ρ = - 0.436; p-value = 0.001). Regression analysis demonstrated that uFABP3/Cr levels were associated with PAD independently of age, sex, hypercholesterolemia, smoking, prior history of coronary arterial disease and Estimated Glomerular Filtration rate (eGFR) [odds ratio: 2.34 (95% confidence interval: 1.47-3.75) p-value < 0.001]. Lastly, receiver operator curve (ROC) analysis demonstrated unadjusted area under the curve (AUC) for uFABP3/Cr of 0.79, which improved to 0.86 after adjusting for eGFR, age, hypercholesteremia, smoking and diabetes. In conclusion, our results demonstrate a strong association between uFABP3/Cr and PAD and suggest the potential of uFABP3/Cr in identifying patients with PAD.

Relation of Magnetic Resonance Imaging Based Arterial Signal Enhancement to Markers of Peripheral Artery Disease

Peripheral artery disease (PAD) is associated with impaired lower extremity function. We hypothesized that contrast-enhanced magnetic resonance imaging (CE-MRI) based arterial signal enhancement (SE) measures are associated with markers of PAD. A total of 66 participants were enrolled, 10 were excluded due to incomplete data, resulting in 56 participants for the final analyses (36 PAD, 20 matched controls). MR imaging was performed postreactive hyperemia using bilateral thigh blood-pressure cuffs. First pass-perfusion images were acquired at the mid-calf region with a high-resolution saturation recovery gradient echo pulse sequence, and arterial SE was measured for the lower extremity arteries. As expected, peak walking time (PWT) was reduced in PAD patients compared with controls (282 [248 to 317] sec, vs 353 [346 to 360] sec; p = 0.002), and postexercise ankle brachial index (ABI) decreased in PAD patients but not in controls (PAD: 0.75 ± 0.2, 0.60 [0.5 to 0.7]; p <0.001; vs Controls: 1.17 ± 0.1, 1.19 [1.1 to 1.2]; p = 0.50). Intraclass correlation coefficients were excellent for inter- and intraobserver variability of arterial tracings (n = 10: 0.95 (95%-confidence interval [CI]: 0.94 to 0.96), n = 9: 1.0 (CI: 1.0 to 1.0). Minimum arterial SE was reduced in PAD patients compared with matched controls (128 [110 to 147] A.U. vs 192 [149 to 234] A.U., p = 0.003). Among PAD patients but not in controls the maximum arterial SE was associated with the estimated glomerular filtration rate (eGFR), a marker of renal function (n = 36, ß = 1.37, R² = 0.12, p = 0.025). In conclusion, CE-MRI first-pass arterial perfusion is impaired in PAD patients compared with matched controls and associated with markers of lower extremity ischemia.

Specialised wound care clinics in Spain: distribution and characteristics

OBJECTIVE

To determine the number of specialised wound care units/clinics (SWCUs) in Spain, at present, and to describe their most important characteristics.

METHOD

This was an observational study with a descriptive-analytical, cross-sectional, multicentre approach, where the studied population consisted of SWCUs in Spain. A specific data-collection questionnaire was designed using a modified Delphi method, consisting of four rounds, with the collaboration of 10 wound experts. The final questionnaire included 49 items distributed across four dimensions/areas with a content validity index (CVI-Total for pertinence=0.96 and CVI-Total for relevance=0.94.

RESULTS

A total of 42 SWCUs were included in the study. Most SWCUs were based in hospitals (n=15, 35.7%) or healthcare centres, covering a specific healthcare area (n=17, 40.5%). SWCU coordinators were primarily nurses (n=33, 78.6%). Staff members' professions in SWCUs included registered nurses (n=38 units, 92.7%), nursing assistants (n=8 units, 19.5%), podiatrists (n=8 units, 19.5%), vascular surgeons (n=7 units, 17%), osteopaths (n=2 units, 4.8%) and medical doctors from different specialties (n=3 units, 7.2%). For wound aetiology, the most prevalent wounds managed were diabetic foot ulcers (n=38 units, 90.5%), followed by venous leg ulcers (n=36 units, 85.7%) and arterial ischaemic ulcers (n=36 units, 85.7%). A statistically significant association was found between the number of staff members in a SWCU and the existence of resistance/opposition barriers when developing a SWCU (Chi-square test, p=0.049; Cramér's V=0.34; 34%), as well as between resistance/opposition barriers when developing a SWCU and a nurse as coordinator of a SWCU (MacNemar test, p=0.007, Cramér's V=0.35; 35%).

CONCLUSION

The typical SWCU implemented in Spain is located in a hospital or integrated in a healthcare structure that offers coverage to a whole health area and providing services for people with hard-to-heal wounds (wound management and prevention) and health professionals (advice, consultancy and training/education). Despite the growing number of SWCUs in Spain, the future of this new organisational model is uncertain, as there can be barriers to creating them and some deficiencies, such as low staff numbers, which need to be addressed.

Thermographic Characterization of Cutaneous Ulcers of Different Etiologies

The characterization of the temperature of skin ulcers may provide preliminary diagnostic evidence. The aim of this study was to characterize cutaneous ulcers of different etiologies by infrared thermography. 122 cutaneous ulcers of 87 patients (age 60.1 ± 15.7 years) were evaluated, allocated into five groups: venous ulcers (VU) n = 26, arterial ulcers (AU) n = 20, mixed ulcers (MU) n = 25, pressure ulcers (PU) n = 29, and neuropathic ulcers (NU) n = 22. The cutaneous temperature was recorded by infrared thermography (FLIR-450™); we also evaluated the ulcer area, the ankle brachial index (ABI), the range of motion (ROM) of the ankle, and pain. For the different variables, the statistical analysis was performed using the Kruskal Wallis test, ANOVA, the chi-squared test, and the Spearman test (SPSS™ software version 20, p < 0.05). A significant difference was found between the temperatures of PU and NU. The ABI was significantly lower in the MU and AU groups, and pain was also higher in these groups. The ROM was decreased in all groups, and the MU and VU groups had the lowest ROM. There was no correlation between temperature and the clinical findings (ABI, ROM, and pain). There was a moderate correlation in the analysis between the temperature and the area of the ulcer in the PU group, as larger ulcers had lower temperatures. It is possible to characterize cutaneous ulcers by infrared thermography, and there are temperature differences among ulcers with different etiologies.

Peripheral arterial disease diagnosis and management in primary care: a qualitative study

BACKGROUND

Patients diagnosed with peripheral arterial disease (PAD) are at an increased risk of coronary heart disease, stroke, heart attack, and PAD progression. If diagnosed early, cardiovascular risk factors can be treated and the risk of other cardiovascular diseases can be reduced. There are clear guidelines on PAD diagnosis and management, but little is known about the issues faced in primary care with regards adherence to these, and about the impact of these issues on patients.

AIM

To identify the issues for primary care health professionals (HPs) and patients in PAD diagnosis and management, and to explore the impact of these on HPs and PAD patients.

DESIGN & SETTING

Qualitative study conducted in a primary care setting in the North East of England. Data was collected between December 2014 and July 2017.

METHOD

Semi-structured interviews and focus groups were conducted with PAD register patients (n = 17), practice nurses ([PNs], n = 17), district nurses (DNs], n = 20), tissue viability nurses (n = 21), and GPs (n = 21).

RESULTS

HPs' attitudes to PAD, difficulty accessing tests, and patient delays impacted upon diagnosis. Some HPs had a reactive approach to PAD identification. Patients lacked understanding about PAD and some reported a delay consulting their GP after the onset of PAD symptoms. After diagnosis, few were attending for regular GP follow-up.

CONCLUSION

Patient education about PAD symptoms and risks, and questioning about exercise tolerance, could address the problem of under-reporting. Annual reviews could provide an opportunity to probe for PAD symptoms and highlight those requiring further investigation. Improved information when PAD is diagnosed and, considering the propensity for patients to tolerate worsening symptoms, the introduction of annual follow-up (at minimum) is warranted.

The reliability of the ankle brachial index: a systematic review

BACKGROUND

The ankle brachial index (ABI) is widely used in clinical practice as a non-invasive method to detect the presence and severity of peripheral arterial disease (PAD). Current guidelines suggest that it should be used to monitor potential progression of PAD in affected individuals. As such, it is important that the test is reliable when used for repeated measurements, by the same or different health practitioners. This systematic review aims to examine the literature to evaluate the inter- and intra-rater reliability of the ABI.

METHODS

A systematic search of MEDLINE, EMBASE and CINAHL Complete was conducted to 20 January 2019. Two authors independently reviewed and selected relevant studies and extracted the data. Methodological quality was determined using the Quality Appraisal of Reliability (QAREL) Checklist.

RESULTS

Fifteen studies of ABI reliability in a range of patient populations were identified as suitable for inclusion in the review: seven considered inter-rater reliability, four intra-rater reliability, and four studies evaluated both inter- and intra-rater reliability. Inter-rater reliability was found to be highly variable, with intraclass correlation coefficients (ICC's) ranging from poor to excellent (ICC 0.42-1.00), while intra-rater also demonstrated considerable variation, with ICCs from 0.42-0.98. Meta-analysis was not possible due to the lack of statistical information reported.

CONCLUSIONS

Results of included studies suggest the inter- and intra-tester reliability of the ABI is acceptable. However, inconsistencies in obtaining systolic pressure measurements, calculating ABI values, and incomplete reporting of methodologies and statistical analysis make it difficult to determine the validity of the results of included studies. Further research, with more consistent reliability methodology, statistical analysis and reporting conducted in populations at risk of PAD is needed to conclusively determine the ABI reliability.

Physiological Association between Limb Ballistocardiogram and Arterial Blood Pressure Waveforms: A Mathematical Model-Based Analysis

By virtue of its direct association with the cardiovascular (CV) functions and compatibility to unobtrusive measurement during daily activities, the limb ballistocardiogram (BCG) is receiving an increasing interest as a viable means for ultra-convenient CV health and disease monitoring. However, limited insights on its physical implications have hampered disciplined interpretation of the BCG and systematic development of the BCG-based approaches for CV health monitoring. In this study, a mathematical model that can predict the limb BCG in responses to the arterial blood pressure (BP) waves in the aorta was developed and experimentally validated. The validated mathematical model suggests that (i) the limb BCG waveform reveals the timings and amplitudes associated with the aortic BP waves; (ii) mechanical filtering exerted by the musculoskeletal properties of the body can obscure the manifestation of the arterial BP waves in the limb BCG; and (iii) the limb BCG exhibits meaningful morphological changes in response to the alterations in the CV risk predictors. The physical insights garnered by the analysis of the mathematical model may open up new opportunities toward next generation of the BCG-based CV healthcare techniques embedded with transparency, interpretability, and robustness against the external variability.

Non-invasive assessment of peripheral arterial disease: Automated ankle brachial index measurement and pulse volume analysis compared to duplex scan

Objectives:

This cross-sectional study aimed to individually and cumulatively compare sensitivity and specificity of the (1) ankle brachial index and (2) pulse volume waveform analysis recorded by the same automated device, with the presence or absence of peripheral arterial disease being verified by ultrasound duplex scan.

Methods:

Patients (n=205) referred for lower limb arterial assessment underwent ankle brachial index measurement and pulse volume waveform recording using volume plethysmography, followed by ultrasound duplex scan. The presence of peripheral arterial disease was recorded if ankle brachial index <0.9; pulse volume waveform was graded as 2, 3 or 4; or if haemodynamically significant stenosis >50% was evident with ultrasound duplex scan. Outcome measure was agreement between the measured ankle brachial index and interpretation of pulse volume waveform for peripheral arterial disease diagnosis, using ultrasound duplex scan as the reference standard.

Results:

Sensitivity of ankle brachial index was 79%, specificity 91% and overall accuracy 88%. Pulse volume waveform sensitivity was 97%, specificity 81% and overall accuracy 85%. The combined sensitivity of ankle brachial index and pulse volume waveform was 100%, specificity 76% and overall accuracy 85%.

Conclusion:

Combining these two diagnostic modalities within one device provided a highly accurate method of ruling out peripheral arterial disease, which could be utilised in primary care to safely reduce unnecessary secondary care referrals.

Atypical leg symptoms: does routine measurement of the ankle brachial pressure index (ABPI) in primary care benefit patients?

Background : Managing patients with atypical leg symptoms in primary care can be problematic. Determining the ankle brachial pressure index (ABPI) may be readily performed to help diagnose peripheral arterial disease, but is often omitted where signs and symptoms are unclear. Question: Does routine measurement of ABPI in patients with atypical leg symptoms aid management increase satisfaction and safely reduce hospital referral? Methodology: Patients with atypical leg symptoms but no skin changes or neurological symptoms underwent clinical review and Doppler ABPI measurement (suspicious finding ≤ 1.0). Testing was performed by the same doctor (study period: 30 months). Patient outcomes were determined from practice records, hospital letters and a telephone survey. Results : The study comprised 35 consecutive patients (males: N = 15), mean age 64 years (range: 39-88). Presentation included pain, cold feet, cramps, irritation and concerns regarding circulation. Prior to ABPI measurement, referral was considered necessary in 10, not required in 22 and unclear in 3. ABPI changed the referral decision in 10 (29%) and confirmed the decision in 25 (71%). During the study, 10 (29%) patients were referred (9 vascular, 1 neurology). Amongst the vascular referrals, significant peripheral arterial disease has been confirmed in six patients. A further two patients are under review and one did not attend. To date, lack of referral in patients with atypical leg symptoms but a normal ABPI has not increased morbidity. Current status was assessed by telephone review in 16/35 (46% contact rate; mean 18 months, range 2-28). Fifteen patients (94%) appreciated that their symptoms had been quickly and conveniently assessed, 8/11 (73%) with a normal ABPI were reassured by their result and in 8/11 symptoms have resolved. Discussion/Conclusion: APBI conveniently aids management of atypical leg symptoms by detecting unexpected peripheral arterial disease, avoids /confirms the need for referral, reassures patients and guides reassessment. This study suggests ABPI should be used more widely.

Current utility of the ankle-brachial index (ABI) in general practice: implications for its use in cardiovascular disease screening

Background

Peripheral arterial disease (PAD) is a marker of systemic atherosclerosis and associated with a three to six fold increased risk of death from cardiovascular causes. Furthermore, it is typically asymptomatic and under-diagnosed; this has resulted in escalating calls for the instigation of Primary Care PAD screening via Ankle Brachial Index (ABI) measurement. However, there is limited evidence regarding the feasibility of this and if the requisite core skills and knowledge for such a task already exist within primary care. This study aimed to determine the current utility of ABI measurement in general practices across Wales, with consideration of the implications for its use as a cardiovascular risk screening tool.

Method

A self-reporting questionnaire was distributed to all 478 General Practices within Wales, sent via their responsible Health Boards.

Results

The survey response rate was 20%. ABI measurement is primarily performed by nurses (93%) for the purpose of wound management (90%). It is infrequently (73% < 4 times per month) and often incorrectly used (42% out of compliance with current ABI guidance). Only 52% of general practitioners and 16% of nurses reported that patients with an ABI of ≤ 0.9 require aggressive cardiovascular disease risk factor modification (as recommended by current national and international guidelines).

Conclusion

ABI measurement is an under-utilised and often incorrectly performed procedure in the surveyed general practices. Prior to its potential adoption as a formalised screening tool for cardiovascular disease, there is a need for a robust training programme with standardised methodology in order to optimise accuracy and consistency of results. The significance of a diagnosis of PAD, in terms of associated increased cardiovascular risk and the necessary risk factor modification, needs to be highlighted.

Concordance between automated oscillometric measurement of ankle-brachial index and traditional measurement by eco-Doppler in patients without peripheral artery disease

AIM

To evaluate the concordance between automated oscillometric measurement (WatchBP® Office ABI) of the ankle- brachial index (ABI) and the traditional measurement by eco-Doppler in a Spanish population without peripheral artery disease attended in primary care.

METHODS

The ABI was determined by both methods in a general population aged ≥ 18 years, from the RICARTO study. The intraclass correlation coefficient was calculated to assess the concordance between both techniques and the Bland-Altman plot was determined to analyze the agreement between them.

RESULTS

A total of 322 subjects (mean age 47.7 ± 16.0 years; 54.3% women) were included in the study. With regard to cardiovascular risk factors, 70.5% of subjects had dyslipidemia, 26.7% hypertension, 24.8% obesity, 8.4% diabetes and 25.5% were smokers. Mean ABI measured by eco-Doppler and the automated method were 1.17 ± 0.1 and 1.2 ± 0.1, respectively (mean differences - 0.03 ± 0.09; p < 0.001). The Pearson correlation coefficient and the intraclass correlation coefficient were in both cases 0.70.

CONCLUSIONS

The automated oscillometric measurement of ABI is a reliable and useful alternative to conventional eco-Doppler determination in the general population without peripheral artery disease attended in primary care.

Training to Measure Ankle–Brachial Index at the Undergraduate Level

We examined the effectiveness of teaching ankle–brachial index (ABI) measurement to medical students. ABI was estimated in 28 lower limbs by an experienced vascular surgeon. After a 2-week training course, 5 fourth-year students repeated the estimations and their results were compared with that of the trainer’s. There was no difference in ABI values between trainees and trainer for subjects with mild-to-moderate peripheral arterial disease (PAD; 0.77 ± 0.22 vs 0.77 ± 0.19, respectively, P = .95). In the 4 normal limbs, ABI was 1.37 ± 0.12 and 1.16 ± 0.11, as measured by the trainer and the trainees, respectively ( P < .00001). In subjects with severe PAD, trainees tended to overestimate ABI ( P = .0002) in the beginning of the educational process, but this was no longer the case at a later stage of the training with no difference in ABI values between the 2 examiner groups ( P = .09). In conclusion, training of medical students in ABI measurement can be helpful toward accurate estimation of PAD and merits further practice.

Comparison between oscillometric- and Doppler-ABI in elderly individuals

Peripheral arterial disease (PAD) generally remains under-recognized, mainly due to the specialized technical skills required to detect the low values of the ankle-brachial index (ABI). As a simpler and faster alternative to the standard method using continuous-wave Doppler ultrasound, we evaluated automated oscillometric ABI measurement by VP-2000 with an elderly cohort of 113 subjects (age range, 61 to 88 years). The standard deviation in ABIs measured by the Doppler method was statistically greater than that measured by the oscillometric method for each of the two legs (P < 0.001). Correlations in ABIs between the two methods were 0.46 for the left leg and 0.61 for the right leg; this result appears to have been caused by interobserver variation in the Doppler ABI measurements. While the trend showing greater differences between average oscillometric- and Doppler-ABIs was significant at the lower ABI ranges, there was little indication of differences in measurements having an average ABI > 1.1. The difference between the methods was suggestively larger in subjects who were smokers than in non-smokers (P = 0.09), but the difference was not affected by other potential atherosclerotic risk factors, including age at examination (P > 0.50). A larger difference at lower ABIs led to better PAD detection by the Doppler method compared to the oscillometric method (sensitivity = 50%, specificity = 100%), although the overall agreement was not small (Cohen’s Kappa = 0.65). Our findings indicate that oscillometric devices can provide more accurate estimation of the prevalence of PAD in elderly individuals than the conventional Doppler method.

[Use of pulse oximetry as screening method for peripheral arterial disease in patients admitted to a general medicine service]

INTRODUCTION

Ankle-brachial index measured by a continuous wave Doppler device remains as the reference method for office diagnosis of peripheral arterial disease. This method is time consuming, requires an appropriate device and training of the examiner. We evaluated the usefulness of pulse oximetry as an easier method to screen for peripheral arterial disease.

METHODS

A total of 110 subjects were selected by opportunistic sampling among patients admitted to a general medicine service. Entry criteria were age older than 50 years and having an additional cardiovascular risk factor. Patients with known cardiovascular disease were excluded. We measured oxygen saturation (SaO2) by means of a pocket finger tip pulse oximeter at 4 limbs. SaO2 was measured at right and left index fingers and great toes with patient lying and after elevating the foot 30 cm above the bed. We considered as abnormal a difference in SaO2 greater than 2% between fingers and toes. Brachial index was estimated by means of a handheld Doppler device.

RESULTS

The prevalence of peripheral arterial disease was 10% (95% confidence interval [CI], 6%-14%). Pulse oximetry has sensitivity 12% (95%CI, 4%-37%), specificity 67% (95%CI, 60%-74%), positive likelihood ratio 0.43 (95%CI, 0.11-1.19), negative likelihood ratio 1.27 (95%CI, 0.91-1.45) and area under the receiving operating characteristics curve 0.75 (95%CI, 0.67-0.82).

CONCLUSIONS

Pulse oximetry showed low accuracy as screening method for peripheral arterial disease. Simpler and more accurate devices than ankle-brachial index measured by Doppler are necessary to ease the screening of peripheral arterial disease.

Resting Doppler ankle brachial pressure index measurement: a literature review

Peripheral vascular disease (PVD) is under-diagnosed in primary and acute settings. The use of Doppler ankle brachial pressure index (ABPI) is effective in diagnosing PVD , aid in determining aetiology of leg ulcers and is cost efficient in reducing the effects of atherosclerosis and cardiovascular events. The aim of this literature review was to review practitioners' experience in using Doppler ABPI, different skills used to measure ABPI and to examine practitioners' confidence in ABPI. The findings identified variation in method for Doppler measurement: including position of the artery, arm measurement, resting period and type of equipment for measuring blood pressure, variations in practitioners' training and experience have demonstrated variability in ABPI results. Although limited in number, the studies have demonstrated knowledge gap, and the need for training among health professionals.

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.

Peripheral arterial disease associated with caries and periodontal disease

BACKGROUND

Peripheral arterial disease (PAD) is an important cardiovascular disorder of the peripheral arteries. Chronic infections, such as periodontitis, may play an important role in the etiology and pathophysiology of PAD and other cardiovascular conditions. Recently, Streptococcus mutans has been found with high frequency in atheromatous plaques. The aim of this study is to evaluate the possible clinical and microbiologic association between PAD and periodontitis and dental caries.

METHODS

Thirty patients with PAD and 30 control individuals were selected. PAD and its severity were established by the use of the ankle-brachial index (ABI). Clinical attachment loss (AL); probing depth; decayed, missing, and filled teeth (DMFT) index; and C-reactive protein (CRP) levels were evaluated. The presence of bacterial DNA from Streptococcus mutans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, Treponema denticola, and Aggregatibacter actinomycetemcomitans was identified by polymerase chain reaction in subgingival biofilm and serum.

RESULTS

Patients with ≥30% AL ≥ 4 mm had six-fold increased risk of having PAD (odds ratio = 8.18; 95% confidence interval = 1.21 to 35.23; P = 0.031). There was statistical difference in the CRP (P = 0.0413) and DMFT index (P = 0.0002), with elevated number of missing teeth (P = 0.0459) in the PAD group compared with the control group. There were no significant differences in the frequency of bacteria in serum and subgingival plaque.

CONCLUSION

There was a positive relationship between periodontitis based on AL and PAD determined by the ABI (odds ratio = 8.18).

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

BACKGROUND

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.

AIMS

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.

DESIGN

Epidemiological observational study.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Vascular Laboratory for Critical Limb Ischaemia

This is a narrative review on vascular assessment for critical limb ischaemia in the past and present combining Finnish and Japanese experience.

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.

Ankle-Brachial Index determination and peripheral arterial disease diagnosis by an oscillometric blood pressure device in primary care: validation and diagnostic accuracy study

OBJECTIVES

To determine the level of agreement between a 'conventional' Ankle-Brachial Index (ABI) measurement (using Doppler and mercury sphygmomanometer taken by a research nurse) and a 'pragmatic' ABI measure (using an oscillometric device taken by a practice nurse) in primary care. To ascertain the utility of a pragmatic ABI measure for the diagnosis of peripheral arterial disease (PAD) in primary care.

DESIGN

Cross-sectional validation and diagnostic accuracy study. Descriptive analyses were used to investigate the agreement between the two procedures using the Bland and Altman method to determine whether the correlation between ABI readings varied systematically. Diagnostic accuracy was assessed via sensitivity, specificity, accuracy, likelihood ratios, positive and negative predictive values, with ABI readings dichotomised and Receiver Operating Curve analysis using both univariable and multivariable logistic regression.

SETTING

Primary care in metropolitan and rural Victoria, Australia between October 2009 and November 2010.

PARTICIPANTS

250 persons with cardiovascular disease (CVD) or at high risk (three or more risk factors) of CVD.

RESULTS

Despite a strong association between the two method's measurements of ABI there was poor agreement with 95% of readings within ±0.4 of the 0.9 ABI cut point. The multivariable C statistic of diagnosis of PAD was 0.89. Other diagnostic measures were sensitivity 62%, specificity 92%, positive predictive value 67%, negative predictive value 90%, accuracy 85%, positive likelihood ratio 7.3 and the negative likelihood ratio 0.42.

CONCLUSIONS

Oscillometric ABI measures by primary care nurses on a population with a 22% prevalence of PAD lacked sufficient agreement with conventional measures to be recommended for routine diagnosis of PAD. This pragmatic method may however be used as a screening tool high-risk and overt CVD patients in primary care as it can reliably exclude the condition.

To screen or not to screen for peripheral arterial disease in subjects aged 80 and over in primary health care: a cross-sectional analysis from the BELFRAIL study

BACKGROUND

Peripheral arterial disease (PAD) is common in older people. An ankle-brachial index (ABI) < 0.9 can be used as an indicator of PAD. Patients with low ABI have increased mortality and a higher risk of serious cardiovascular morbidity. However, because 80% of the patients are asymptomatic, PAD remains unrecognised in a large group of patients. The aims of this study were 1) to examine the prevalence of reduced ABI in subjects aged 80 and over, 2) to determine the diagnostic accuracy of the medical history and clinical examination for reduced ABI and 3) to investigate the difference in functioning and physical activity between patients with and without reduced ABI.

METHODS

A cross-sectional study embedded within the BELFRAIL study. A general practitioner (GP) centre, located in Hoeilaart, Belgium, recruited 239 patients aged 80 or older. Only three criteria for exclusion were used: urgent medical need, palliative situation and known serious dementia. The GP recorded the medical history and performed a clinical examination. The clinical research assistant performed an extensive examination including Mini-Mental State Examination (MMSE), Geriatric Depression Scale (GDS-15), Activities of Daily Living (ADL), Tinetti test and the LASA Physical Activity Questionnaire (LAPAQ). ABI was measured using an automatic oscillometric appliance.

RESULTS

In 40% of patients, a reduced ABI was found. Cardiovascular risk factors were unable to identify patients with low ABI. A negative correlation was found between the number of cardiovascular morbidities and ABI. Cardiovascular morbidity had a sensitivity of 65.7% (95% CI 53.4-76.7) and a specificity of 48.6% (95% CI 38.7-58.5). Palpation of the peripheral arteries showed the highest negative predictive value (77.7% (95% CI 71.8-82.9)). The LAPAQ score was significantly lower in the group with reduced ABI.

CONCLUSION

The prevalence of PAD is very high in patients aged 80 and over in general practice. The clinical examination, cardiovascular risk factors and the presence of cardiovascular morbidity were not able to identify patients with a low ABI. A screening strategy for PAD by determining ABI could be considered if effective interventions for those aged 80 and over with a low ABI become available through future research.

A review of simple, non-invasive means of assessing peripheral arterial disease and implications for medical management

Abstract Atherosclerotic peripheral arterial disease (PAD) is highly prevalent in the elderly and subjects with atherosclerotic risk factors such as smoking, diabetes mellitus, hypertension, and hyperlipidemia. Importantly, PAD is rarely an isolated condition, but rather a manifestation of systemic atherosclerosis. Hence, there is often coexisting disease in the coronary and cerebral arteries and, consequently, an increased risk of myocardial infarction and stroke. Intermittent claudication is the classic symptom of PAD, yet up to 50% of patients are asymptomatic. Despite the availability of reliable, non-invasive screening tests, PAD is largely underdiagnosed and undertreated, mostly due to the paucity of symptoms and underutilization of screening tools. The ankle-brachial index (ABI), a simple, rapid, and inexpensive diagnostic tool, holds much prognostic value for PAD diagnosis and is ideal for implementation in the primary care physician's office. The early detection of PAD with ABI screening and subsequent medical management represents a critical opportunity to prevent considerable vascular morbidity and mortality. The management of PAD must address claudication symptoms (with cilostazol or pentoxifylline, or in severe cases endovascular or surgical revascularization) and modifiable atherosclerotic risk factors (with an aggressive global risk-reduction regimen involving lifestyle modifications, exercise, smoking cessation, and antiplatelet, lipid-lowering, and antihypertensive therapy).