Limited Adherence to Peripheral Arterial Disease Guidelines and Suboptimal Ankle Brachial Index Reliability in Dutch Primary Care

Peripheral artery disease recognition, diagnosis, and management in general practice in the Republic of Ireland and England: an online survey

BACKGROUND

Peripheral artery disease (PAD) is common and associated with future cardiovascular events. PAD is underdiagnosed, which limits opportunities to address secondary prevention of cardiovascular disease. It is unknown how closely guidelines for detection of PAD are followed in primary care.

AIM

To survey GPs' attitudes to diagnosis and follow-up of patients with PAD.

DESIGN & SETTING

Online survey of GPs in England and the Republic of Ireland (RoI).

METHOD

GPs' approaches to management of PAD were assessed using likelihood ratings (scales of 0-10) and discrete questions. Findings were summarised as proportions, or median and interquartile ranges (IQR).

RESULTS

In total, 111 responses were analysed; 68 (61%) from England and 43 (39%) from the RoI. Considering a hypothetical patient at risk of PAD, likelihood of GPs enquiring about PAD symptoms (leg pains: 3/10 or erectile dysfunction: 2/10) was low. GPs in the RoI compared with GPs in England more often examined the heart (10/10 versus 7/10) or carotid vessels (5/10 versus 1/10). Lower limb pulses were palpated in response to symptoms or signs of PAD. In England 25% of practitioners, and in the RoI 55% of practitioners, reported that they do not measure ankle-brachial index (ABI).

CONCLUSION

Currently, detection of PAD is generally triggered by 'classical' leg claudication symptoms, while known vascular risk factors appear to elicit little consideration. ABI measurement is not performed by many practitioners, suggesting that a proportion of vascular referrals must be based on history and examination findings alone. Opportunities to recognise PAD are missed.

Duplex ultrasound and pedal acceleration time as tools to evaluate foot perfusion: a literature review

Currently, the standard non-invasive test for diagnosing Peripheral Arterial Disease is the Ankle-Brachial Index. However, this test becomes unfeasible in a certain population. New evidence proposes the pedal acceleration time, an ultrasound index, as an alternative test. An integrative bibliographic review was carried out between June 3, 2022 and January 8, 2023, to investigate this new index as a tool to assess foot perfusion. Papers published in English, Portuguese, or Spanish between 2012 and 2022 were searched on PubMed, Google Scholar, and Scielo, using the keywords "Peripheral Arterial Disease" AND "Acceleration Time" AND (Pedal OR Plantar). Research that didn't assess foot perfusion using the methods of interest or did not present human data and also case series or reports were excluded. Seven out of the sixty-six articles identified in the searches were selected for the review, all of which had notable methodological limitations. Pedal acceleration time seems to be able to diagnose and stratify and may reflect prognosis.

Mobile health technologies to improve walking distance in people with intermittent claudication

BACKGROUND

Peripheral arterial disease (PAD) is the obstruction or narrowing of the large arteries of the lower limbs, which can result in impaired oxygen supply to the muscle and other tissues during exercise, or even at rest in more severe cases. PAD is classified into five categories (Fontaine classification). It may be asymptomatic or various levels of claudication pain may be present; at a later stage, there may be ulceration or gangrene of the limb, with amputation occasionally being required. About 20% of people with PAD suffer from intermittent claudication (IC), which is muscular discomfort in the lower extremities induced by exertion and relieved by rest within 10 minutes; IC causes restriction of movement in daily life. Treatment for people with IC involves addressing lifestyle risk factors. Exercise is an important part of treatment, but supervised exercise programmes for individuals with IC have low engagement levels and high attrition rates. The use of mobile technologies has been suggested as a new way to engage people with IC in walking exercise interventions. The novelty of the intervention, low cost for the user, automation, and ease of access are some of the advantages mobile health (mhealth) technologies provide that give them the potential to be effective in boosting physical activity in adults.

OBJECTIVES

To assess the benefits and harms of mobile health (mhealth) technologies to improve walking distance in people with intermittent claudication.

SEARCH METHODS

The Cochrane Vascular Information Specialist conducted systematic searches of the Cochrane Vascular Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and CINAHL, and also searched the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov. The most recent searches were carried out on 19 December 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in people aged 18 years or over with symptomatic PAD and a clinical diagnosis of IC. We included RCTs comparing mhealth interventions to improve walking distance versus usual care (no intervention or non-exercise advice), exercise advice, or supervised exercise programmes. We excluded people with chronic limb-threatening ischaemia (Fontaine III and IV).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were change in absolute walking distance from baseline, change in claudication distance from baseline, amputation-free survival, revascularisation-free survival. Our secondary outcomes were major adverse cardiovascular events, major adverse limb events, above-ankle amputation, quality of life, and adverse events. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included four RCTs involving a total of 614 participants with a clinical diagnosis of IC. The duration of intervention of the four included RCTs ranged from 3 to 12 months. Participants were randomised to either mhealth or control (usual care or supervised exercise programme). All four studies had an unclear or high risk of bias in one or several domains. The most prevalent risk of bias was in the area of performance bias, which was rated high risk as it is not possible to blind participants and personnel in this type of trial. Based on GRADE criteria, we downgraded the certainty of the evidence to low, due to concerns about risk of bias, imprecision, and clinical inconsistency. Comparing mhealth with usual care, there was no clear evidence of an effect on absolute walking distance (mean difference 9.99 metres, 95% confidence interval (CI) -27.96 to 47.93; 2 studies, 503 participants; low-certainty evidence). None of the included studies reported on change in claudication walking distance, amputation-free survival, or revascularisation-free survival. Only one study reported on major adverse cardiovascular events (MACE) and found no clear difference between groups (risk ratio 1.37, 95% CI 0.07 to 28.17; 1 study, 305 participants; low-certainty evidence). None of the included studies reported on major adverse limb events (MALE) or above-ankle amputations.

AUTHORS' CONCLUSIONS

Mobile health technologies can be used to provide lifestyle interventions for people with chronic conditions, such as IC. We identified a limited number of studies that met our inclusion criteria. We found no clear difference between mhealth and usual care in improving absolute walking distance in people with IC; however, we judged the evidence to be low certainty. Larger, well-designed RCTs are needed to provide adequate statistical power to reliably evaluate the effects of mhealth technologies on walking distance in people with IC.

Screening for Peripheral Artery Disease Using an Automated Four-Limb Blood Pressure Monitor Equipped with Toe-Brachial Index Measurement

Toe-brachial index (TBI) measurement helps to detect peripheral artery disease (PAD) in patients with incompressible ankle arteries due to medial arterial calcification, which is most frequently associated with diabetes. We aimed to evaluate how an automated four-limb blood pressure monitor equipped with TBI measurement could contribute to PAD screening. In 117 patients (mean age 63.2 ± 12.8 years), ankle-brachial index (ABI) measurement was performed using the Doppler-method and the MESI mTablet. TBI was obtained via photoplethysmography (MESI mTablet, SysToe) and a laser Doppler fluxmeter (PeriFlux 5000). Lower limb PAD lesions were evaluated based on vascular imaging. A significant correlation was found between Doppler and MESI ankle-brachial index values (r = 0.672), which was stronger in non-diabetic (r = 0.744) than in diabetic (r = 0.562) patients. At an ABI cut-off of 0.9, Doppler (AUC = 0.888) showed a sensitivity/specificity of 67.1%/97.4%, MESI (AUC 0.891) exhibited a sensitivity/specificity of 57.0%/100%; at a cut-off of 1.0, MESI demonstrated a sensitivity/specificity of 74.7%/94.8%. The TBI values measured using the three devices did not differ significantly (p = 0.33). At a TBI cut-off of 0.7, MESI (AUC = 0.909) revealed a sensitivity/specificity of 92.1%/67.5%. Combining MESI ABI and TBI measurements recognised 92.4% of PAD limbs. Using an ABI cut-off level of 1.0 and sequential TBI measurement increases the sensitivity of the device in detecting PAD. The precise interpretation of the obtained results requires some expertise.

Diagnosis and Treatment of Lower Extremity Arterial Disease-A Survey among Family Medicine Trainees in Poland

Guidelines point to the ankle-brachial index (ABI) as a non-invasive tool for the initial diagnosis of lower extremity artery disease (LEAD). Questions have been raised whether primary practices should perform ABI. An online questionnaire was distributed among family medicine trainees in two academic centers in Poland. The questionnaire aimed to establish their knowledge about LEAD management and their opinion on the usefulness of ABI measurement and other LEAD diagnostic methods in primary care. ABI measurement was found either very or moderately useful in LEAD diagnosis by 94.5% of the respondents. Among the three most important elements of LEAD management, lifestyle changes, secondary prevention of atherosclerosis and exercise treatment were chosen, respectively, by 98.6%, 83.6% and 72.6% of them. ABI was seen as a useful diagnostic method at the primary care by 74% of the participants; however, 82.2% of them do not have access to ABI measurement in their workplace. The residents have good knowledge of the diagnostic methods of LEAD and consider ABI measurement as useful in LEAD diagnosis. However, most of them do not have access to ABI measurements in their clinical practices. Future discussion and potential financial changes will be needed for the introduction of ABI measurements into Polish primary care.

Statin use improves survival of patients with known or suspected lower extremity artery disease on all ankle brachial index levels

Background: Statin medication improves the prognosis of patients with lower extremity artery disease (LEAD). Research has previously focused on patients with a lowered ankle brachial index (ABI) excluding patients with a normal or elevated ankle brachial index. The aim of this study was to analyze the impact of statin use on survival and cardiovascular mortality in patients with LEAD of different severity depicted by the ABI level. Patients and methods: 4128 ABI measurements by trained and experienced nurses between 2000 and 2009 were combined with medication data from the Social Insurance Institution and causes of death data from the national causes of death registry. End of follow-up was set at the end of 2014. The data of statin use included all statin medication with the Anatomical Therapeutic Chemical (ATC) classification codes between C10AA01 and C10AA08. Results: 1956 (47.4%) patients had statin medication. Statin use was associated with improved overall survival and amputation free survival (AFS) on all ABI levels. When adjusted for age, sex and diabetes the greatest overall survival benefit from statin use was for the patients with ABI>1.3 (hazard ratio, HR: 0.67, 95% CI: 0.48-0.94, p=0.020, reference group statin non-users) and ABI 0.9-1.3 (HR: 0.78, 95% CI: 0.65-0.94, p=0.008). In propensity score matched pairs statin treatment was associated with significantly lower all-cause mortality (p<0.0001), cardiovascular mortality (p=0.034), cerebrovascular mortality (p=0.003) and embolic stroke related mortality (p=0.001) in patients with ABI >1.3 or <0.9. Overall survival benefit was significant in females with ABI<0.5 and in males across several ABI levels. Conclusions: According to our study, statins seem to improve overall and amputation free survival regardless of ABI level. Statin use was associated with lower mortality from cerebrovascular disease, overall mortality and in the propensity score matched patients with ABI<0.9 or >1.3 with cardiovascular mortality.

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.

The Role of Fatty Acid Binding Protein 3 in Cardiovascular Diseases

Fatty acid binding proteins (FABPs) are proteins found in the cytosol that contribute to disorders related to the cardiovascular system, including atherosclerosis and metabolic syndrome. Functionally, FABPs serve as intracellular lipid chaperones, interacting with hydrophobic ligands and mediating their transportation to sites of lipid metabolism. To date, nine unique members of the FABP family (FABP 1–9) have been identified and classified according to the tissue in which they are most highly expressed. In the literature, FABP3 has been shown to be a promising clinical biomarker for coronary and peripheral artery disease. Given the rising incidence of cardiovascular disease and its associated morbidity/mortality, identifying biomarkers for early diagnosis and treatment is critical. In this review, we highlight key discoveries and recent studies on the role of FABP3 in cardiovascular disorders, with a particular focus on its clinical relevance as a biomarker for peripheral artery disease.

Simplification of ankle-brachial-index measurement using Doppler-waveform classification in symptomatic patients suspected of lower extremity artery disease

Objectives

Ankle-brachial index (ABI) is commonly used for screening lower extremity peripheral artery disease (PAD) according to the international guidelines. Arterial Doppler waveform recordings is a tool to diagnose and assess PAD severity. We hypothesized that ABI measurement could be simplified by measuring only the pressure where the best arterial flow is recorded. The aim of this study was to evaluate the concordance between ABI performed according to the American Heart Association guidelines (AHA-ABI) and ABI measured according to best arterial waveform (FLOW-ABI).

Design

This was a monocentric cross-sectional study.

Methods

We included patients with exertional limb symptoms suspected of PAD. Arterial Doppler waveforms and ABI were acquired on both lower extremities at the pedis and tibial posterior arteries. Each arterial waveform was classified using the Saint-Bonnet classification. Concordances were analyzed with the kappa coefficient (confidence interval 95%). Exercise PAD study was registered n° NCT03186391.

Results

In total, one hundred and eighty-eight patients (62+/−12 years and 26.8+/−4.5 kg/m²) with exertional limb symptoms were included from May 2016 to June 2019. On each extremity, FLOW-ABI had excellent concordance for the diagnosis of PAD with the AHA-ABI with a kappa of 0.95 (95% CI: 0.90, 0.99) in the right extremity and 0.91 (95% CI: 0.86, 0.97) in the left extremity.

Conclusion

There is almost perfect concordance between AHA-ABI and FLOW-ABI. Thus, ABI can be simplified into five pressure measurements instead of seven in patient suspected of PAD with exertional limb symptoms. The question remains in patients with chronic limb ischemia.

Automated Measurements of Ankle-Brachial Index: A Narrative Review

Peripheral artery disease (PAD) is an atherosclerotic disease that causes obstruction in lower limb arteries. It increases cardiovascular risk even in asymptomatic patients. Accurate diagnostic tools for identification of affected individuals are needed. Recently, there have been attempts to establish a reliable method of automated ankle-brachial index (ABI) identification. A search of PubMed database to identify studies assessing automatic ABI measurements in agreement with standard PAD diagnosis methods was conducted in December 2020. A total of 57 studies were analyzed in the review. The majority of analyzed studies found ABI measured by automatic oscillometric devices to be potentially feasible for use. Some note that, even though the Doppler and oscillometric methods are not fully interchangeable, the oscillometric devices could be used in screening. Significantly fewer publications are available on automatic plethysmographic devices. For photoplethysmography, most studies reported either good or moderate agreement with reference standards. For air plethysmography, poorer agreement with Doppler ABI is suggested. It is noted that pulse volume recording (PVR) function may improve the diagnostic accuracy of the devices.

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.

Diagnostic Performance of Ankle-Brachial Pressure Index in Lower Extremity Arterial Disease

Introduction  Ankle-brachial pressure indices (ABIs) continue to form the basis of diagnostics for lower extremity arterial disease (LEAD). However, there remains a paucity of data to support its accuracy. This study aims to evaluate its diagnostic sensitivity and specificity using established arterial-imaging modalities as a benchmark.

Methods  In this retrospective study, a regional, prospectively maintained, vascular laboratory database was interrogated to identify referred patients with arterial disease who underwent concomitant assessment with ABI and lower limb arterial duplex ultrasound (DUS). Duplex acted as the reference standard. Those who had peripheral computed tomography angiogram (CTA) within 3 months of initial assessment were included in a subgroup analysis to correlate ABI with CTA. The primary end point was the sensitivity and specificity of ABI compared with DUS as the reference standard.

Results  Concomitant assessment was performed in 438 limbs (250 patients) over a 27-month period. The ABI was normal (0.9 to 1.4) in 196 limbs (44.9%) and abnormal in the remaining 241 limbs (55.1%). False-positive results occurred in 83 out of 241 limbs (34.4%), and false-negative results occurred in 54 limbs out of 196 (27.5%). True-positive results were 158 out of 241 limbs (65.6%), whereas true-negative results were 142 out of 196 limbs (72.4%). ABI using DUS as a benchmark identified a sensitivity for peripheral artery disease of 72.3% and a specificity of 69.3%. Concomitant CTA imaging was available in 200 limbs. The sensitivity and specificity of ABI correlated with CTA were 65.5 and 68.8%, respectively.

Conclusion  ABIs have a moderate predictive value in the diagnosis of LEAD. Normal range outcomes cannot be taken to infer the absence of LEAD and, as such, further arterial imaging in the form of DUS or angiography should be strongly considered in those with suspected underlying disease requiring intervention. Further noninvasive tests such as exercise studies or pulse volume waveforms should be considered, if diagnostic uncertainty exists, in those requiring nonoperative intervention and risk factor control.

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.

Evidence-based medical treatment of peripheral arterial disease: A rapid review

ABSTRACT Introduction: Peripheral arterial disease (PAD) treatment guidelines recommend the use of statins and antiplatelets in all PAD patients to reduce adverse cardiovascular and limb-related outcomes. In addition, hypertension and diabetes should be treated to reach recommended targets. The aim of this rapid review was to evaluate the level of adherence to evidence-based medical therapy (EBMT) recommended by PAD treatment guidelines in the real-world setting. Methods: We searched PubMed and Embase using keywords, MeSH and Emtree terms related to the population, exposure and outcomes from their inception to 22 September 2020. We included randomised controlled trials, non-randomised studies, and observational studies reporting adherence to at least 1 of these 4 drug classes: (1) statins, (2) antiplatelets, (3) antihypertensives and (4) antidiabetic drugs. Non-English articles, abstracts, dissertations, animal studies and case reports or series were excluded. A narrative summary of the results was performed. Results: A total of 42 articles were included in the review. The adherence to lipid-lowering drugs/statins ranged from 23.5 to 92.0% and antiplatelets from 27.5 to 96.3%. Only 7 and 5 studies reported use of “any anti-hypertensive” and “any anti-diabetic” medications, respectively, and the proportion of the cohort treated were generally close to the proportion with hypertension and/or diabetes. Adherence in studies published in 2016–2020 ranged from 52.4–89.6% for lipid-lowering drugs and 66.2–96.3% for antiplatelets. Conclusion: EBMT adherence in PAD patients was highly variable and a substantial proportion in many settings were undertreated. There was also a notable lack of studies in Asian populations. Keywords: Evidence-practice gap, medication adherence, pharmacoepidemiology

Diagnostic accuracy of automated oscillometric determination of the ankle-brachial index in peripheral artery disease

OBJECTIVE

Peripheral artery disease (PAD) is underdiagnosed in primary care settings, partly because of limited accuracy of the Doppler ankle-brachial index (ABI). This study aimed to assess the diagnostic accuracy of an automated oscillometric ABI device compared with reference standard vascular laboratory Doppler ABI equipment and to examine the influence of oscillometric errors on performance.

METHODS

Consecutive patients who were referred to a large general hospital for an ABI measurement were invited to participate. In each patient, the oscillometric analysis was followed by the Doppler analysis. Legs with incompressible ankle arteries were excluded from analysis. ABI values were compared using the Bland-Altman method. Oscillometric errors were defined as the incapacity of the oscillometer to report a value of ABI. A receiver operating characteristic curve was constructed, and the area under the curve was computed.

RESULTS

A total of 201 patients participated. The Bland-Altman plot showed a mean difference of 0.05 ± 0.12 (limits of agreement, -0.20 to 0.29), representing a small ABI overestimation after oscillometry. Oscillometric errors occurred more commonly in limbs with PAD than in limbs without PAD (28% and 7%, respectively; P < .001). Considering a 0.9 threshold and after oscillometric error exclusion, the oscillometric ABI showed a 74% sensitivity and a 97% specificity for a diagnosis of PAD. When oscillometric errors were considered as abnormal ABIs, sensitivity increased to 86% and specificity was maintained at 95%. The receiver operating characteristic curve showed an area under the curve of 0.96. The best oscillometric ABI cutoff point was 1.00. Using this threshold and when considering oscillometric errors as abnormal ABIs, sensitivity improved to 94% while maintaining specificity at 92%.

CONCLUSIONS

Oscillometric ABI showed good diagnostic accuracy compared with the reference standard. However, the high incidence of oscillometric errors and the challenges to correctly interpret readings may limit the use of the oscillometric method in PAD diagnosis.

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.

Feasibility and Clinical Relevance of a Mobile Intervention Using TrackPAD to Support Supervised Exercise Therapy in Patients With Peripheral Arterial Disease: Study Protocol for a Randomized Controlled Pilot Trial

Background

Peripheral arterial disease (PAD) is a common and severe disease with a highly increased cardiovascular morbidity and mortality. Through the circulatory disorder and the linked undersupply of oxygen carriers in the lower limbs, the ongoing decrease of the pain-free walking distance occurs with a significant reduction in patients’ quality of life. Studies including activity monitoring for patients with PAD are rare and digital support to increase activity via mobile health technologies is mainly targeted at patients with cardiovascular disease in general. The special requirement of patients with PAD is the need to reach a certain pain level to improve the pain-free walking distance. Unfortunately, both poor adherence and availability of institutional resources are major problems in patient-centered care.

Objective

The objective of this trackPAD pilot study is to evaluate the feasibility of a mobile phone–based self tracking app to promote physical activity and supervised exercise therapy (SET) in particular. We also aim for a subsequent patient centered adjustment of the app prototype based on the results of the app evaluation and process evaluation.

Methods

This study was designed as a closed user group trial, with assessors blinded, and parallel group study with face-to-face components for assessment with a follow-up of 3 months. Patients with symptomatic PAD (Fontaine stage IIa or IIb) and possession of a mobile phone were eligible. Eligible participants were randomly assigned into study and control group, stratified by their distance covered in the 6-min walk test, using the software TENALEA. Participants randomized to the study group received usual care and the mobile intervention (trackPAD) for the follow-up period of 3 months, whereas participants randomized to the control group received only usual care. TrackPAD records the frequency and duration of training sessions and pain level using manual user input. Clinical outcome data were collected at the baseline and after 3 months via validated tools (6-min walk test, ankle-brachial index, and duplex ultrasound at the lower arteries) and self-reported quality of life. Usability and quality of the app was determined using the user version of the Mobile Application Rating Scale.

Results

The study enrolled 45 participants with symptomatic PAD (44% male). Of these participants, 21 (47%) were randomized to the study group and 24 (53%) were randomized to the control group. The distance walked in the 6-min walk test was comparable in both groups at baseline (study group: mean 368.1m [SD 77.6] vs control group: mean 394.6m [SD 100.6]).

Conclusions

This is the first trial to test a mobile intervention called trackPAD that was designed especially for patients with PAD. Its results will provide important insights in terms of feasibility, effectiveness, and patient preferences of an app-based mobile intervention supporting SET for the conservative treatment of PAD.

International Registered Report Identifier (IRRID)

DERR1-10.2196/13651