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Background: Peripheral arterial disease (PAD) of the lower limbs is caused by atherosclerotic occlusive disease in which narrowing of arteries reduces blood flow to the lower limbs. PAD is common; it is estimated to affect 236 million individuals worldwide. Advanced age, smoking, hypertension, diabetes and concomitant cardiovascular disease are common factors associated with increased risk of PAD. Complications of PAD can include claudication pain, rest pain, wounds, gangrene, amputation and increased cardiovascular morbidity and mortality. It is therefore clinically important to use diagnostic tests that accurately identify PAD. Accurate and timely detection of PAD allows clinicians to implement appropriate risk management strategies to prevent complications, slow progression or intervene when indicated. Toe-brachial index (TBI) and toe systolic blood pressure (TSBP) are amongst a suite of non-invasive bedside tests used to detect PAD. Both TBI and TSBP are commonly utilised by a variety of clinicians in different settings, therefore a systematic review and meta-analysis of their diagnostic accuracy is warranted and highly relevant to inform clinical practice., Objectives: To (1) estimate the accuracy of TSBP and TBI for the diagnosis of PAD in the lower extremities at different cut-off values for test positivity in populations at risk of PAD, and (2) compare the accuracy of TBI and TSBP for the diagnosis of PAD in the lower extremities. Secondary objectives were to investigate several possible sources of heterogeneity in test accuracy, including the following: patient group tested (people with type 1 or type 2 diabetes, people with renal disease and general population), type of equipment used, positivity threshold and type of reference standard., Search Methods: The Cochrane Vascular Information Specialist searched the MEDLINE, Embase, CINAHL, Web of Science, LILACS, Zetoc and DARE databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 27 February 2024., Selection Criteria: We included diagnostic case-control, cross-sectional, prospective and retrospective studies in which all participants had either a TSBP or TBI measurement plus a validated method of vascular diagnostic imaging for PAD. We needed to be able to cross-tabulate (2 x 2 table) results of the index test and the reference standard to include a study. To be included, study populations had to be adults aged 18 years and over. We included studies of symptomatic and asymptomatic participants. Studies had to use TSBP and TBI (also called toe-brachial pressure index (TBPI)), either individually, or in addition to other non-invasive tests as index tests to diagnose PAD in individuals with suspected disease. We included data collected by photoplethysmography, laser Doppler, continuous wave Doppler, sphygmomanometers (both manual and aneroid) and manual or automated digital equipment., Data Collection and Analysis: Two review authors independently completed data extraction using a standardised form. We extracted data to populate 2 x 2 contingency tables when available (true positives, true negatives, false positives, false negatives). Where data were not available to enable statistical analysis, we contacted study authors directly. Two review authors working independently undertook quality assessment using QUADAS-2, with disagreements resolved by a third review author. We incorporated two additional questions into the quality appraisal to aid our understanding of the conduct of studies and make appropriate judgements about risk of bias and applicability., Main Results: Eighteen studies met the inclusion criteria; 13 evaluated TBI only, one evaluated TSBP only and four evaluated both TBI and TSBP. Thirteen of the studies used colour duplex ultrasound (CDU) as a reference standard, two used computed tomography angiography (CTA), one used multi-detector row tomography (MDCT), one used angiography and one used a combination of CDU, CTA and angiography. TBI was investigated in 1927 participants and 2550 limbs. TSBP was investigated in 701 participants, of which 701 limbs had TSBP measured. Studies were generally of low methodological quality, with poor reporting of participant recruitment in regard to consecutive or random sampling, and poor reporting of blinding between index test and reference standard, as well as timing between index test and reference standard. The certainty of evidence according to GRADE for most studies was very low., Authors' Conclusions: Whilst a small number of diagnostic test accuracy studies have been completed for TBI and TSBP to identify PAD, the overall methodological quality was low, with most studies providing a very low certainty of evidence. The evidence base to support the use of TBI and TSBP to identify PAD is therefore limited. Whilst both TBI and TSBP are used extensively clinically, the overall diagnostic performance of these tests remains uncertain. Future research using robust methods and clear reporting is warranted to comprehensively determine the diagnostic test accuracy of the TBI and TSBP for identification of PAD with greater certainty. However, conducting such research where some of the reference tests are invasive and only clinically indicated in populations with known PAD is challenging., (Copyright © 2024 The Authors. Cochrane Database of Systematic Reviews published by John Wiley & Sons, Ltd. on behalf of The Cochrane Collaboration.)

Background: Continuous-wave Doppler is frequently used for detecting peripheral arterial disease in patients with diabetes; however, there is limited evidence investigating diagnostic accuracy. This study aimed to determine sensitivity and specificity of continuous-wave Doppler for detecting peripheral arterial disease in populations with, and without, diabetes and to investigate the influence of disease severity on sensitivity of continuous-wave Doppler for detecting peripheral arterial disease., Results: Data from 396 participants were included. Using colour Duplex ultrasound as reference standard (N=66), printed continuous-wave Doppler waveform analysis sensitivity was 81.75% (95% confidence interval: 76.75 to 85.88) and specificity 89.34% (95% confidence interval: 82.62 to 93.67). Printed continuous-wave Doppler waveform analysis sensitivity for peripheral arterial disease was comparable to sensitivity calculated using angiography as the reference standard (81.67%; 95% confidence interval: 69.56 to 90.48). Sensitivity and specificity were unaffected by diabetes diagnosis (n = 176), sensitivity 82.76% (95% confidence interval: 74.86 to 88.55), and specificity 88.33% (95% confidence interval: 77.82 to 94.23)., Conclusion: Continuous-wave Doppler is a fair assessment tool for peripheral arterial disease in a community-based sample with suspected peripheral arterial disease. Diagnostic accuracy of continuous-wave Doppler for peripheral arterial disease is unaffected by the presence of diabetes.

The postexercise ankle-brachial index (ABI) is recommended in patients with normal resting ABI when peripheral artery disease (PAD) is suspected. The aims of this study were to determine the comparative diagnostic accuracy of the resting and postexercise ABI for detecting PAD, and, the effect of the presence of diabetes on these. Three methods of interpretation currently in use were also investigated: a reduction in postexercise ABI by >20% compared to resting ABI, an ABI value of ≤0.90 postexercise, or a reduction in systolic ankle pressure of >30 mmHg postexercise. This retrospective study used colour duplex ultrasound (CDU) as the reference standard. In 278 limbs (whole group), the resting ABI had an overall area under the curve (AUC) of 0.71, with the postexercise ABI yielding a similar diagnostic accuracy of AUC 0.72. In the non-diabetes group ( n=171), the resting ABI had an overall AUC of 0.74 and the postexercise ABI had a similar AUC of 0.76. In the diabetes group ( n=107), overall accuracy was reduced compared to the non-diabetes group, with the resting ABI having an overall AUC of 0.65 and the postexercise ABI yielding a similar accuracy with an AUC of 0.64. The overall diagnostic accuracy of the postexercise ABI for diagnosing PAD was not greatly improved compared to resting ABI. Given the lower overall diagnostic accuracy in the diabetes group, both the resting and the postexercise ABI results in diabetes populations should be interpreted with caution. There is a risk of undiagnosed disease if relying on these results alone to determine lower limb vascular status.

Background: The resting systolic toe pressure (TP) is a measure of small arterial function in the periphery. TP is used in addition to the ankle-brachial index when screening for peripheral arterial disease (PAD) of the lower limb in those with diabetes, particularly in the presence of lower limb medial arterial calcification. It may be used as an adjunct assessment of lower limb vascular function and as a predictor of wound healing. The aim of this study was to determine the diagnostic accuracy of TP for detecting PAD in people with and without diabetes., Methods: This was a retrospective case-control study. Two researchers extracted information from consecutive patient records, including TP measurements, colour Duplex ultrasound results, demographic information, and medical history. Measures of diagnostic accuracy were determined by receiver operating curve (ROC) analysis, and calculation of sensitivity, specificity, and positive and negative likelihood ratios., Results: Three hundred and nintey-four participants with suspected PAD were included. In the diabetes group ( n  = 176), ROC analysis of TP for detecting PAD was 0.78 (95%CI: 0.69 to 0.84). In the control group ( n  = 218), the ROC of TP was 0.73 (95%CI: 0.70 to 0.80). TP had highest sensitivity when anatomical distribution of disease was both proximal and distal (diabetes group: 79.49%, the control group: 82.61%). TP yielded highest sensitivity in mild disease (50-75% stenosis) in diabetes group, (81.82%) and moderate disease (>75% stenosis) in control group (80.77%)., Conclusions: Our findings indicate that TPs are useful to assist in diagnosing PAD in clinical practice, however, results should be interpreted with caution due to the small probability of PAD being present with a negative test., Competing Interests: This research was completed under the ethical approval of the University of Newcastle ethics committee approval number H2010–1230.Not applicable.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.