Can we measure the ankle-brachial index using only a stethoscope? A pilot study

Novel markers of endothelial dysfunction in hepatitis C virus-related cirrhosis: More than a mere prediction of esophageal varices

BACKGROUND

Hepatitis C virus (HCV) infection may affect lipid metabolism by enhancing the circulating levels of inflammatory cytokines, together with its impact on endothelial function.

AIM

To evaluate the potential correlation of changes in lipid profile, carotid intima-media thickness (CIMT), and ankle-brachial index with the severity of fibrosis, grades of esophageal varices (EVs), and fibrosis indices.

METHODS

The study included 240 subjects who were divided into 3 groups; group 1 (n = 90, HCV-related cirrhotic patients with EVs), group 2 (n = 90, HCV-related cirrhotic patients without EVs), and group 3 (n = 60, served as the healthy control group). All patients underwent routine laboratory tests, including a lipid profile assay. Low-density lipoproteins (LDL)/platelet count and platelet/splenic diameter ratios were calculated. Abdominal ultrasonography, CIMT by carotid Doppler, bedside ankle-brachial index (ABI), liver stiffness measurement, and upper gastrointestinal endoscopy were performed.

RESULTS

Multivariate logistic regression revealed that very-low-density lipoprotein (VLDL) (β = 0.988, odds ratio 2.5, P = 0.001), LDL/platelet count ratio (β = 1.178, odds ratio 3.24, P = 0.001), CIMT (β = 1.37, odds ratio 3.9, P = 0.001), and ABI (β = 2.3, odds ratio 5.9, P = 0.001) were the key variables associated with significant fibrosis, EVs and endothelial dysfunction. CIMT and LDL/platelet count ratio were predictive of advanced fibrosis and EVs at cutoff values of 1.1 mm and 1 mm, respectively, with an area under the curve (AUC) of 0.966 and 0.960 (P = 0.001), while VLDL and ABI at a cutoff of 16.5 mg/dL and 0.94 were predictive of advanced fibrosis and EVs with an AUC of 0.891 and 0.823, respectively (P = 0.001).

CONCLUSION

CIMT, ABI, VLDL, LDL/platelet count ratio are good non-invasive predictors of advanced fibrosis, presence of EVs, and endothelial dysfunction in liver cirrhosis.

Concurrent Validity of Digital Vascular Auscultation for the Assessment of Blood Flow Obliteration on the Radial Artery in Healthy Subjects

This study aimed to determine the validity of digital vascular auscultation for the assessment of changes in the radial pulse in healthy subjects, using Doppler sonography as a validated test referent. Sixty-one non-symptomatic subjects (mean age of 52.5 ± 16.1 years) were assigned and evaluated under one of the following conditions: In condition 1, blood flow of the radial artery was not modified; for condition 2, blood flow of the radial artery was modified using a pressure sleeve around the humerus. The radial pulse was then measured three times with each diagnostic tool by three different blinded evaluators. Both instruments demonstrated a high association between the identification of blood flow modifications or not and the assigned condition (p < 0.001). A strong concordance between the two devices when detecting the “changes” or “no changes” in blood flow was demonstrated (k = 0.936, p < 0.001). Stethoscope sensitivity was 95%, and specificity was 99%. In conclusion, digital vascular auscultation seems to be a valid technique to examine blood flow changes of the radial artery in non-symptomatic subjects, and it could be useful for physical therapists when combined with provocative tests for the screening of possible thoracic outlet syndrome in patients.

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

BACKGROUND

Peripheral arterial disease (PAD) of the lower limb is common, with prevalence of both symptomatic and asymptomatic disease estimated at 13% in the over 50 age group. Symptomatic PAD affects about 5% of individuals in Western populations between the ages of 55 and 74 years. The most common initial symptom of PAD is muscle pain on exercise that is relieved by rest and is attributed to reduced lower limb blood flow due to atherosclerotic disease (intermittent claudication). The ankle brachial index (ABI) is widely used by a variety of healthcare professionals, including specialist nurses, physicians, surgeons and podiatrists working in primary and secondary care settings, to assess signs and symptoms of PAD. As the ABI test is non-invasive and inexpensive and is in widespread clinical use, a systematic review of its diagnostic accuracy in people presenting with leg pain suggestive of PAD is highly relevant to routine clinical practice.

OBJECTIVES

To estimate the diagnostic accuracy of the ankle brachial index (ABI) - also known as the ankle brachial pressure index (ABPI) - for the diagnosis of peripheral arterial disease in people who experience leg pain on walking that is alleviated by rest.

SEARCH METHODS

We carried out searches of the following databases in August 2013: MEDLINE (Ovid SP),Embase (Ovid SP), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO), Latin American and Caribbean Health Sciences (LILACS) (Bireme), Database of Abstracts of Reviews of Effects and the Health Technology Assessment Database in The Cochrane Library, the Institute for Scientific Information (ISI) Conference Proceedings Citation Index - Science, the British Library Zetoc Conference search and Medion.

SELECTION CRITERIA

We included cross-sectional studies of ABI in which duplex ultrasonography or angiography was used as the reference standard. We also included cross-sectional or diagnostic test accuracy (DTA) cohort studies consisting of both prospective and retrospective studies.Participants were adults presenting with leg pain on walking that was relieved by rest, who were tested in primary care settings or secondary care settings (hospital outpatients only) and who did not have signs or symptoms of critical limb ischaemia (rest pain, ischaemic ulcers or gangrene).The index test was ABI, also called the ankle brachial pressure index (ABPI) or the Ankle Arm Index (AAI), which was performed with a hand-held doppler or oscillometry device to detect ankle vessels. We included data collected via sphygmomanometers (both manual and aneroid) and digital equipment.

DATA COLLECTION AND ANALYSIS

Two review authors independently replicated data extraction by using a standard form, which included an assessment of study quality, and resolved disagreements by discussion. Two review authors extracted participant-level data when available to populate 2×2 contingency tables (true positives, true negatives, false positives and false negatives).After a pilot phase involving two review authors working independently, we used the methodological quality assessment tool the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2), which incorporated our review question - along with a flow diagram to aid reviewers' understanding of the conduct of the study when necessary and an assessment of risk of bias and applicability judgements.

MAIN RESULTS

We screened 17,055 records identified through searches of databases. We obtained 746 full-text articles and assessed them for relevance. We scrutinised 49 studies to establish their eligibility for inclusion in the review and excluded 48, primarily because participants were not patients presenting solely with exertional leg pain, investigators used no reference standard or investigators used neither angiography nor duplex ultrasonography as the reference standard. We excluded most studies for more than one reason.Only one study met the eligibility criteria and provided limb-level accuracy data from just 85 participants (158 legs). This prospective study compared the manual doppler method of obtaining an ABI (performed by untrained personnel) with the automated oscillometric method. Limb-level data, as reported by the study, indicated that the accuracy of the ABI in detecting significant arterial disease on angiography is superior when stenosis is present in the femoropopliteal vessels, with sensitivity of 97% (95% confidence interval (CI) 93% to 99%) and specificity of 89% (95% CI 67% to 95%) for oscillometric ABI, and sensitivity of 95% (95% CI 89% to 97%) and specificity of 56% (95% CI 33% to 70%) for doppler ABI. The ABI threshold was not reported. Investigators attributed the lower specificity for doppler to the fact that a tibial or dorsalis pedis pulse could not be detected by doppler in 12 of 27 legs with normal vessels or non-significant lesions. The superiority of the oscillometric (automated) method for obtaining an ABI reading over the manual method with a doppler probe used by inexperienced operators may be a clinically important finding.

AUTHORS' CONCLUSIONS

Evidence about the accuracy of the ankle brachial index for the diagnosis of PAD in people with leg pain on exercise that is alleviated by rest is sparse. The single study included in our review provided only limb-level data from a few participants. Well-designed cross-sectional studies are required to evaluate the accuracy of ABI in patients presenting with early symptoms of peripheral arterial disease in all healthcare settings. Another systematic review of existing studies assessing the use of ABI in alternative patient groups, including asymptomatic, high-risk patients, is required.

Reliability of Doppler and stethoscope methods of determining systolic blood pressures: considerations for calculating an ankle-brachial index

PURPOSE

The purposes of this study were to: (1) identify the interrater and intrarater reliability of systolic blood pressures using a stethoscope and Doppler to determine an ankle-brachial index (ABI), and (2) to determine the correlation between the 2 methods.

BACKGROUND

Peripheral arterial disease (PAD) affects approximately 8 to 12 million people in the United States, and nearly half of those with this disease are asymptomatic. Early detection and prompt treatment of PAD will improve health outcomes. It is important that clinicians perform tests that determine the presence of PAD.

METHOD

Two individual raters trained in ABI procedure measured the systolic blood pressures of 20 individuals' upper and lower extremities. Standard ABI measurement protocols were observed. Raters individually recorded the systolic blood pressures of each extremity using a stethoscope and a Doppler, for a total of 640 independent measures.

RESULTS

Interrater reliability of Doppler measurements to determine SBP at the ankle was very strong (intraclass correlation coefficient [ICC], 0.93-0.99) compared to moderate to strong reliability using a stethoscope (ICC, 0.64-0.87). Agreement between the 2 devices to determine SBP was moderate to very weak (ICC, 0.13-0.61). Comparisons of the use of Doppler and stethoscope to determine ABI showed weak to very weak intrarater correlation (ICC, 0.17-0.35). Linear regression analysis of the 2 methods to determine ABI showed positive but weak to very weak correlations (r2 = .013, P = .184).

CONCLUSIONS

A Doppler ultrasound is recommended over a stethoscope for accuracy in systolic pressure readings for ABI measurements.

Sensitivity and specificity of the ankle—brachial index to diagnose peripheral artery disease: a structured review

The ankle—brachial index (ABI) is a simple, inexpensive diagnostic test for peripheral artery disease (PAD). However, it has shown variable accuracy for identification of significant stenosis. The authors performed a structured review of the sensitivity and specificity of ABI ≤ 0.90 for the diagnosis of PAD. MEDLINE, EMBASE, Cochrane databases, Science Citation Index database, and Biological Abstracts database were searched for studies of the sensitivity and specificity of using ABI ≤ 0.90 for the diagnosis of PAD. Eight studies comprising 2043 patients (or limbs) met the inclusion criteria. The result indicated that, although strict inclusion criteria on studies were formulated, different reference standards were found in these studies, and methods of ABI determination and characteristics of populations varied greatly. A high level of specificity (83.3—99.0%) and accuracy (72.1—89.2%) was reported for an ABI ≤ 0.90 in detecting ≥ 50% stenosis, but there were different levels of sensitivity (15—79%). Sensitivity was low, especially in elderly individuals and patients with diabetes. In conclusion, the test of ABI ≤ 0.90 can be a simple and useful tool to identify PAD with serious stenosis, and may be substituted for other non-invasive tests in clinical practice.