Cost-effectiveness of Diagnostic Tools to Establish the Presence of Peripheral Arterial Disease in People With Diabetes.

OBJECTIVE: To evaluate the cost-effectiveness of point-of-care duplex ultrasound (PAD-scan) and other bedside tests for the diagnosis of peripheral arterial disease (PAD) in people with diabetes. BACKGROUND: PAD is a risk factor for cardiovascular disease, diabetic foot ulceration (DFU), and amputation in diabetic patients. Diagnosis enables optimization of therapies to manage these risks. PAD-scan can be performed by frontline staff and has been shown to be the most accurate bedside test. However, its cost-effectiveness has not been investigated. METHODS: A Markov model was constructed to estimate the health outcomes and costs over 5 years of different testing strategies applied to a cohort of diabetic patients. Bedside tests investigated were PAD-scan, ankle-brachial pressure index, toe-brachial pressure index, audible and visual Doppler, transcutaneous pressure of oxygen, and pulse palpation. Health outcomes were incidence of new DFU, major cardiovascular events, amputation, death, and DFU healing rates. Sensitivity analyses were performed. RESULTS: PAD-scan was the most cost-effective bedside test with an incremental cost-effectiveness ratio of £11,391/quality-adjusted life years. PADscan had the highest probability (78.7%) of having the greatest net benefit at a willingness to pay threshold of £20,000 per quality-adjusted life years. It reduced the number of amputations by 24% and the number of cardiovascular deaths by 10% over 5 years, compared to toe-brachial pressure index (next best alternative). PAD-scans superiority in incremental cost-effectiveness ratio occurred at a PAD prevalence threshold of 0.24. DISCUSSION: PAD-scan is a cost-effective test for the detection of PAD in patients with diabetes.

Quantifying the burden of survivorship associated with infrarenal abdominal aortic aneurysms.

OBJECTIVES: Survivorship encompasses the physical, psychological, social, functional, and economic experience of a living with a chronic condition for both the patient and their caregiver. It is made up of nine distinct domains and remains understudied in nononcological pathologies, including infrarenal abdominal aortic aneurysmal disease (AAA). This review aims to quantify the extent to which existing AAA literature addresses the burden of survivorship. METHODS: The MEDLINE, EMBASE, and PsychINFO databases were searched from 1989 through September 2022. Randomized controlled trials, observational studies, and case series were included. Eligible studies had to detail outcomes related to survivorship in patients with AAA. Owing to the heterogeneity between studies and outcomes, no meta-analysis was conducted. Study quality was assessed with specific risk of bias tools. RESULTS: A total of 158 studies were included. Of these, only five (treatment complications, physical functioning, comorbidities, caregivers, and mental health) of the nine domains of survivorship have been studied previously. The available evidence is of variable quality; most studies display a moderate to high risk of bias, are of an observational study design, are based within a limited number of countries, and consist of an insufficient follow-up period. The most frequent complication after EVAR was endoleak. EVAR is associated with poorer long-term outcomes compared with open surgical repair in most studies retrieved. EVAR showed better outcomes in regard to physical functioning in the short term, but this advantage was lost in the long term. The most common comorbidity studied was obesity. No significant differences were found between open surgical repair and EVAR in terms of impact on caregivers. Depression is associated with various comorbidities and increased the risk of a nonhospital discharge. CONCLUSIONS: This review highlights the absence of robust evidence regarding survivorship in AAA. As a result, contemporary treatment guidelines rely on historic quality-of-life data that are narrow in scope and nonrepresentative of contemporary clinical practice. As such, there is an urgent need to reevaluate the aims and methodology associated with traditional quality-of-life research moving forward.

Diagnostic Accuracy of Point-of-care Tests Used to Detect Arterial Disease in Diabetes: TEsting for Arterial Disease in Diabetes (TrEAD) Study.

OBJECTIVE: We compared the diagnostic performance of a novel point-of-care duplex ultrasound test (podiatry ankle duplex scan; PAD-scan) against commonly used bedside tests for the detection of PAD in diabetes. BACKGROUND: PAD is a major risk factor for diabetic foot ulceration and amputation. Its diagnosis is fundamental though challenging. Although a variety of bedside tests are available, there is no agreement as to which is the most useful. PAD-scan may be advantageous over current tests as it allows for vessel visualization and more accurate arterial waveform assessment. However, its accuracy has not been previously evaluated. METHODS: From March to October 2019, we recruited 305 patients from 2 diabetic foot clinics. The diagnostic performance of ankle-brachial pressure index, toe-brachial pressure index, transcutaneous pressure of oxygen, pulse palpation, and ankle waveform assessment using PAD-scan and Doppler devices (audible and visual waveform assessment) were assessed. The reference test was a full lower limb duplex ultrasound. RESULTS: Based on the reference test, 202 (66.2%) patients had evidence of PAD. PAD-scan had a significantly higher sensitivity [95%, confidence interval (CI) 90%-97%) as compared to all other tests. Particularly low sensitivities were seen with pulse palpation (43%, CI 36%-50%) and transcutaneous pressure of oxygen (31%, CI 24%-38%). PAD-scan had a lower specificity (77%, CI 67%-84%) compared to toe-brachial pressure index (86%, CI 78%-93%; P < 0.001), but not statistically different when compared to all other tests. CONCLUSIONS: PAD-scan has superior diagnostic utility and is a valid first line investigation.

Machine learning-based classification of arterial spectral waveforms for the diagnosis of peripheral artery disease in the context of diabetes: A proof-of-concept study.

BACKGROUND: Point-of-care duplex ultrasound has emerged as a promising test for the diagnosis of peripheral artery disease (PAD). However, the interpretation of morphologically diverse Doppler arterial spectral waveforms is challenging and associated with wide inter-observer variation. The aim of this study is to evaluate the utility of machine learning techniques for the diagnosis of PAD from Doppler arterial spectral waveforms sampled at the level of the ankle in patients with diabetes. METHODS: In two centres, 590 Doppler arterial spectral waveform images (PAD 369, no-PAD 221) from 305 patients were prospectively collected. Doppler arterial spectral waveform signals were reconstructed. Blinded full lower-limb reference duplex ultrasound results were used to label waveform according to PAD status (i.e., PAD, no-PAD). Statistical metrics and multiscale wavelet variance were extracted as discriminatory features. A long short-term memory (LSTM) network was used for the classification of raw signals, and logistic regression (LR) and support vector machines (SVM) were used for classification of extracted features. Signals and feature vectors were randomly divided into training (80%) and testing (20%) sets. RESULTS: The highest overall accuracy was achieved using a logistic regression model with a combination of statistical and multiscale wavelet variance features, with 88% accuracy, 92% sensitivity, and 82% specificity. The area under the receiver operating characteristics curve (AUC) was 0.93. CONCLUSION: We have constructed a machine learning algorithm with high discriminatory ability for the diagnosis of PAD using Doppler arterial spectral waveforms sampled at the ankle vessels.

Factors associated with infrainguinal bypass graft patency at 1-year; a retrospective analysis of a single centre experience.

INTRODUCTION: The aim of this study was to identify factors associated with primary graft patency 1 year following open lower limb revascularisation (LLR) at a tertiary referral vascular service. METHODS: A retrospective analysis of patients undergoing infra-inguinal bypass surgery between January 2016 and May 2017 at a tertiary vascular centre (St Mary's Hospital, London) was performed. Data regarding patient demographics, comorbidities, type of operation and post-operative anti-thrombotic strategy were collected. Quality of run-off score was assessed from pre-operative imaging. RESULTS: Seventy-seven cases were included in the analysis. Overall, the primary patency rate at 1-year was 63.6% (n = 49/77) and the secondary patency rate was 67.5% (n = 52/77). Independent variables with statistically significant inferior patency rates at 1-year were (1) bypasses with below knee targets (p = 0.0096), (2) chronic limb threatening ischaemia indication (p = 0.038), (3) previous ipsilateral revascularisation (p < 0.001) and (4) absence of hypertension history (p = 0.041). There was also a trend towards significance for American Society of Anesthesiologists (ASA) grade (p = 0.06). Independent variables with log-rank test p values of <0.1 were included in a Cox proportional hazards model. The only variable with a statistically significant impact on primary patency rates was previous open or endovascular ipsilateral revascularisation (HR 2.44 (1.04-5.7), p = 0.04). CONCLUSION: At 1-year follow-up, previous ipsilateral revascularisation was the most significant factor in affecting patency rates. Patients in this subgroup should therefore be deemed high-risk, which should be reflected in the informed consent and peri-operative management.

A Pilot Study of Heart Rate Variability Synchrony as a Marker of Intraoperative Surgical Teamwork and Its Correlation to the Length of Procedure.

Objective: Quality of intraoperative teamwork may have a direct impact on patient outcomes. Heart rate variability (HRV) synchrony may be useful for objective assessment of team cohesion and good teamwork. The primary aim of this study was to investigate the feasibility of using HRV synchrony in surgical teams. Secondary aims were to investigate the association of HRV synchrony with length of procedure (LOP), complications, number of intraoperative glitches and length of stay (LOS). We also investigated the correlation between HRV synchrony and team familiarity, pre- and intraoperative stress levels (STAI questionnaire), NOTECHS score and experience of team members. Methods: Ear, nose and throat (ENT) and vascular surgeons (consultant and registrar team members) were recruited into the study. Baseline demographics including level of team members' experience were gathered before each procedure. For each procedure, continuous electrocardiogram (ECG) recording was performed and questionnaires regarding pre- and intraoperative stress levels and non-technical skills (NOTECHS) scores were collected for each team member. An independent observer documented the time of each intraoperative glitch. Statistical analysis was conducted using stepwise multiple linear regression. Results: Four HRV synchrony metrics which may be markers of efficient surgical collaboration were identified from the data: 1. number of HRV synchronies per hour of procedure, 2. number of HRV synchrony trends per hour of procedure, 3. length of HRV synchrony trends per hour of procedure, 4. area under the HRV synchrony trend curve per hour of procedure. LOP was inversely correlated with number of HRV synchrony trends per hour of procedure (p < 0.0001), area under HRV synchrony trend curve per hour of procedure (p = 0.001), length of HRV synchrony trends per hour of procedure (p = 0.002) and number of HRV synchronies per hour of procedure (p < 0.0001). LOP was positively correlated with: FS (p = 0.043; R = 0.358) and intraoperative STAI score of the whole team (p = 0.007; R = 0.493). Conclusions: HRV synchrony metrics within operating teams may be used as an objective marker to quantify surgical teamwork. We have shown that LOP is shorter when the intraoperative surgical teams' HRV is more synchronised.

A systematic review and meta-analysis of the diagnostic accuracy of point-of-care tests used to establish the presence of peripheral arterial disease in people with diabetes.

OBJECTIVE: No agreement has been reached regarding which bedside test is the most useful for the diagnosis of peripheral arterial disease (PAD) in patients with diabetes. The aim of the present systematic review and meta-analysis was to evaluate the performance of bedside tests for the detection of PAD in individuals with diabetes. METHODS: MEDLINE and EMBASE databases were systematically searched for studies providing data on the diagnostic performance of bedside tests used for the detection of PAD in those with diabetes. A meta-analysis was performed to obtain pooled estimates of sensitivity and specificity for the diagnosis of PAD. RESULTS: A total of 18 studies, reporting on a total of 3016 limbs of diabetic patients, were included in our qualitative review. Of these, 11 studies (1543 limbs) were included in the meta-analysis of diagnostic accuracy: ankle-brachial pressure index (9 studies and 1368 limbs; sensitivity, 63.5% [95% confidence interval (CI), 51.7%-73.9%]; specificity, 89.3% [95% CI, 81.1%-94.2%]); toe-brachial pressure index (3 studies and 221 limbs; sensitivity, 83.0% [95% CI, 59.1-94.3%]; specificity, 66.3% [95% CI, 41.3%-84.6%]); and tibial waveform assessment (4 studies and 397 limbs; sensitivity, 82.8% [95% CI, 73.3%-89.4%], specificity, 86.8% [95% CI, 75.5%-93.3%]). Overall, we found a high risk of bias across the studies, most frequently relating to patient selection and the lack of blinding. CONCLUSIONS: The toe-brachial pressure index, pulse oximetry, and tibial arterial waveform assessment demonstrated some promise, warranting further investigation.

Wearable Activity Monitors in Home Based Exercise Therapy for Patients with Intermittent Claudication: A Systematic Review.

OBJECTIVE: Intermittent claudication (IC) can severely limit functional capacity and quality of life. Supervised exercise therapy is the recommended first line management; however, this is often limited by accessibility, compliance and cost. As such, there has been an increased interest in the use of wearable activity monitors (WAMs) in home based telemonitoring exercise programmes for claudicants. This review aims to evaluate the efficacy of WAM as a feedback and monitoring tool in home based exercise programmes for patients with IC. DATA SOURCES: A search strategy was devised. The databases MEDLINE, EMBASE, and Web of Science were searched through to April 2020. REVIEW METHODS: Randomised trials and prospective trials were included. Eligible trials had to incorporate WAMs as a feedback tool to target walking/exercise behaviour. The primary outcome was the change in walking ability. Study quality was assessed with risk of bias tool. RESULTS: A total of 1148 records were retrieved. Of these, eight randomised controlled trials and one prospective cohort study, all of which compared a WAM intervention against standard care and/or supervised exercise, met the inclusion criteria. Owing to heterogeneity between studies, no meta-analysis was conducted. WAM interventions improved measures of walking ability (heterogeneous outcomes such as maximum walking distance, claudication distance and six minute walk distance), increased daily walking activity (steps/day), cardiovascular metrics (maximum oxygen consumption), and quality of life. CONCLUSION: There is some evidence that home based WAM interventions are beneficial for improving walking ability and quality of life in patients with IC. However, existing studies are limited by inadequate sample size, duration, and appropriate power. Achieving consensus on outcome reporting and study methods, as well as maximising device adherence, is needed.

Harnessing Machine Learning to Personalize Web-Based Health Care Content.

Web-based health care content has emerged as a primary source for patients to access health information without direct guidance from health care providers. The benefit of this approach is dependent on the ability of patients to access engaging high-quality information, but significant variability in the quality of web-based information often forces patients to navigate large quantities of inaccurate, incomplete, irrelevant, or inaccessible content. Personalization positions the patient at the center of health care models by considering their needs, preferences, goals, and values. However, the traditional methods used thus far in health care to determine the factors of high-quality content for a particular user are insufficient. Machine learning (ML) uses algorithms to process and uncover patterns within large volumes of data to develop predictive models that automatically improve over time. The health care sector has lagged behind other industries in implementing ML to analyze user and content features, which can automate personalized content recommendations on a mass scale. With the advent of big data in health care, which builds comprehensive patient profiles drawn from several disparate sources, ML can be used to integrate structured and unstructured data from users and content to deliver content that is predicted to be effective and engaging for patients. This enables patients to engage in their health and support education, self-management, and positive behavior change as well as to enhance clinical outcomes.

Factors Affecting Engagement in Web-Based Health Care Patient Information: Narrative Review of the Literature.

BACKGROUND: Web-based content is rapidly becoming the primary source of health care information. There is a pressing need for web-based health care content to not only be accurate but also be engaging. Improved engagement of people with web-based health care content has the potential to inform as well as influence behavioral change to enable people to make better health care choices. The factors associated with better engagement with web-based health care content have previously not been considered. OBJECTIVE: The aims of this study are to identify the factors that affect engagement with web-based health care content and develop a framework to be considered when creating such content. METHODS: A comprehensive search of the PubMed and MEDLINE database was performed from January 1, 1946, to January 5, 2020. The reference lists of all included studies were also searched. The Medical Subject Headings database was used to derive the following keywords: "patient information," "online," "internet," "web," and "content." All studies in English pertaining to the factors affecting engagement in web-based health care patient information were included. No restrictions were set on the study type. Analysis of the themes arising from the results was performed using inductive content analysis. RESULTS: The search yielded 814 articles, of which 56 (6.9%) met our inclusion criteria. The studies ranged from observational and noncontrolled studies to quasi-experimental studies. Overall, there was significant heterogeneity in the types of interventions and outcome assessments, which made quantitative assessment difficult. Consensus among all authors of this study resulted in six categories that formed the basis of a framework to assess the factors affecting engagement in web-based health care content: easy to understand, support, adaptability, accessibility, visuals and content, and credibility and completeness. CONCLUSIONS: There is a paucity of high-quality data relating to the factors that improve the quality of engagement with web-based health care content. Our framework summarizes the reported studies, which may be useful to health care content creators. An evaluation of the utility of web-based content to engage users is of significant importance and may be accessible through tools such as the Net Promoter score. Web 3.0 technology and development of the field of psychographics for health care offer further potential for development. Future work may also involve improvement of the framework through a co-design process.

Arterial spectral waveform analysis in the prediction of diabetic foot ulcer healing.

OBJECTIVE: We assessed the association between (1) severity of vessel wall calcification, (2) number of patent vessels at the ankle and (3) arterial spectral waveform features, as assessed on a focused ankle Duplex ultrasound (DUS), and healing at 12-months in a cohort of patients who had their diabetic foot ulcers conservatively managed. RESEARCH DESIGN AND METHODS: Scans performed on 50 limbs in 48 patients were included for analysis. Patient health records were prospectively reviewed for 12-months to assess for the outcome of ulcer healing. RESULTS: We identified that the number of waveform components, peak systolic velocity, systolic rise time and long forward flow as well as the number of vessels patent at the ankle on DUS, may be useful independent predictors of healing, as noted by the trend towards statistical significance. CONCLUSION: Arterial spectral waveform features may be useful in predicting the chance of diabetic foot ulcer healing.

A novel team Familiarity Score for operating teams is a predictor of length of a procedure: A retrospective Bayesian analysis.

OBJECTIVE: The aim of our retrospective study was to assess whether a novel team Familiarity Score (FS) is associated with the length of procedure (LOP), postoperative length of stay (LOS), and complication rate after vascular procedures. METHODS: We retrospectively analyzed 326 vascular procedures performed at a tertiary care vascular surgery center between April 2012 and September 2014. Data collected included patients' age, American Society of Anesthesiologists grade, LOP, type and urgency of procedure, LOS, and complications. Familiarity Score (FS) was defined as the sum of the number of times that each possible pair of the team (vascular consultant, vascular registrar, scrub nurse, anesthetic consultant) within the team had worked together during the previous 6 months, divided by the number of possible combinations of pairs in the team. Bayesian statistics was used to analyze the data. RESULTS: FS was significantly associated with type and urgency of the procedure (Bayes factor [BF] >1000). Emergency procedures were performed by less familiar teams, and the least familiar teams were involved in the emergency aortic procedures-endovascular and open. FS was strongly associated with LOP (BF = 37) but not with LOS (BF = 4.0) and complication rate. CONCLUSIONS: FS in vascular teams was shown to be strongly associated with LOP, suggesting that more familiar teams might collaborate more efficiently.

Wearable Sensor Technology Efficacy in Peripheral Vascular Disease (wSTEP): A Randomized Controlled Trial.

OBJECTIVE: To evaluate the effect of using wearable activity monitors (WAMs) in patients with intermittent claudication (IC) within a single-center randomized controlled trial. BACKGROUND: WAMs allow users to set daily activity targets and monitor their progress. They may offer an alternative treatment to supervised exercise programs (SEPs) for patients with IC. METHODS: Thirty-seven patients with IC were recruited and randomized into intervention or control group. The intervention consisted of a feedback-enabled, wrist-worn activity monitor (WAM) in addition to access to SEP. The control group was given access to SEP only. The outcome measures were maximum walking distance (MWD), claudication distance (CD), and quality of life as measured by the VascuQol questionnaire. Participants were assessed upon recruitment, and at 3, 6, and 12 months. RESULTS: Patients in the WAM group showed significant improvement in MWD at 3 and 6 months (80-112 m, to 178 m; P < 0.001), which was sustained at 12 months. The WAM group also increased CD (40 vs 110 m; P < 0.001) and VascuQol score (4.7 vs 5.8; P = 0.004). The control group saw a temporary increase in VascuQol score at 6 months (4.5 vs 4.7; P = 0.028), but no other improvements in MWD or CD were observed. Significantly higher improvements in MWD were seen in the WAM group compared with that in the control group at 6 months (82 vs -5 m; P = 0.009, r = 0.47) and 12 months (69 vs 7.5 m; P = 0.011, r = 0.52). CONCLUSIONS: The study demonstrates the significant, sustained benefit of WAM-led technologies for patients with IC. This potentially resource-sparing intervention is likely to provide a valuable adjunct or alternative to SEP.

Validation of an assessment tool for pre-operative EVAR planning.

INTRODUCTION: Current methods of teaching endovascular aortic aneurysm repair (EVAR) planning involve non-criteria-based observations that lack validity. The primary aim of this study was to validate an EVAR Planning Objective Structured Assessment of Skill (EpOSAS) tool for the assessment of pre-operative EVAR planning skills. METHODS: Content analysis was performed in order to inform the formulation of EpOSAS domains. Thirty-five participants planned two cases of infra-renal abdominal aortic aneurysm for EVAR, using the OsiriX 7 platform. EVAR planning measurements, with accompanying screenshots, were uploaded onto an electronic data collection sheet. Performance was assessed by three blinded assessors using the EpOSAS tool. Construct and concurrent validity were evaluated. RESULTS: Inter-observer reliability for the three assessors for total EpOSAS scores was high (Cronbach's α 0.89). There were statistically significant differences in total EpOSAS scores between the different experience groups, demonstrating construct validity (Novice (5.3, IQR 5-5.3), Intermediate (15.3, IQR 14.8-16.8) and Experts (17.5, IQR 17-17.7), p<0.001). A statistically significant correlation was found between total EpOSAS scores and percentage error in measurements, demonstrating concurrent validity (Spearman's rank correlation coefficient: R=-0.250, p<0.001). Receiver-operator characteristics analysis established a cut-off point of 16 out of 18 for determining competence. CONCLUSION: We have developed and validated a tool that can be used for the assessment of pre-operative EVAR planning skills.

Sources of Delay in the Acute Limb Ischemia Patient Pathway.

BACKGROUND: Acute limb ischemia (ALI) continues to pose a significant challenge to clinicians and is associated with an unacceptably high rate of morbidity and mortality. Despite its time critical nature, little is known regarding the delays encountered during the patient pathway. The aim of this study was to identify sources of delay in the patient pathway at our institution. METHODS: Sixty-seven cases of ALI of the lower extremities from 66 patients, who had presented to our center between May 2003 and April 2014, were identified for retrospective analysis. Data were retrieved from the patient records, discharge summaries and hospital laboratory, emergency department and radiology databases. RESULTS: Median time from onset of symptom to arrival at our institution was 11.35 hr (interquartile range [IQR] 6.27-72). Median cumulative time taken from arrival to vascular team review was 40 min (22.5-120), to imaging being performed was 4.75 hr (2.42-17.25), and to intervention being performed was 10.2 hr (4-31). There were significantly longer delays to presentation in those transferred from inpatient beds as compared with those transferred from the emergency department of other hospitals (66 hr [10.3-98] vs. 8 hr [5.6-14.9], P = 0.007). In total, 84.6% of patients underwent preoperative arterial imaging. Time taken from arrival to diagnostic arterial imaging was significantly longer in patients presenting out-of-ours (15 hr [6.5-20.75]) as compared with patients presenting in-hours (3.5 hr [2-6.5], P = 0.014) or during the weekend (2 hr [2-3], P = 0.022). Time from presentation to intervention was significantly shorter in patients presenting over the weekend (3.9 hr [2.6-5.1]) as compared with those presenting in-hours (14.2 hr [6.2-29], P = 0.006) and out-of-hours (16 hr [10-33], P = 0.021). Out-of-hours, a significant portion of the delay, was attributable to imaging (median time to imaging 15 hr). CONCLUSIONS: This study demonstrates the systematic nature of delays in the patient pathway from onset of symptoms to treatment. Several factors including time to patient presentation and time to imaging and delays in timely transfer to an appropriate facility contribute to this. Strategies need to be deployed to reduce time to revascularization.

The impact of a focused vascular lower limb arterial duplex (F-VLAD) scan in management decisions for acute limb ischaemia.

OBJECTIVE: To establish the diagnostic accuracy of a 'focused vascular lower limb arterial duplex scan (F-VLAD)' developed to facilitate rapid decision-making for acute limb ischaemia (ALI). METHODS: Ten cases of ALI were identified from our patient database; clinical details, history and examination findings were extracted from the clinical notes. Original 'full' duplex ultrasound (DUS) pictorial reports were 're-formatted' to include only anatomical segments included in the 'F-VLAD' scan. The series of 10 reports were emailed to 1741 vascular surgeons. Each recipient received a random mixture of full and F-VLAD scans. Participants were asked regarding next step in management and confidence in decision-making (Likert scale; 1 strongly disagree, 5 strongly agree). The cases were again sent out to the same database and respondents were asked as to the cause of ischaemia (embolic or thrombosis). RESULTS: Eighty-one participants responded to the first survey and 43 participants to the second survey. Participants felt more confident making decisions regarding management using the full duplex report compared to the F-VLAD report (4 (3-4) vs 3 (2-4), median (IQR); p<0.001). However, there was no significant difference in diagnostic accuracy (differentiating embolus from thrombosis) when comparing the F-VLAD and full DUS reports (85.4% vs 88.3%; p=0.461). F-VLAD and 'full' DUS reports had comparable sensitivity (85.1% vs 86.8%), specificity (85.6% vs 89.2%),positive predictive value (PPV) (80.4% vs 81.9%) and negative predictive value (NPV) (89.2% vs 92.2%), respectively. CONCLUSION: The F-VLAD scan has comparable accuracy to a traditional full DUS in diagnosing the underlying aetiology of ALI. This may facilitate surgeon-performed point-of-care DUS.

Randomized study of teaching ultrasound-guided vascular cannulation using a phantom and the freehand versus needle guide-assisted puncture techniques.

PURPOSE: The task of ultrasound-guided vessel cannulation can be technically difficult. Needle guides have been designed to facilitate vessel puncture. We aimed to identify and compare the learning curves of participants performing vessel puncture with conventional freehand (FH) and needle guide-assisted (NG) techniques. METHODS: Thirty-six participants were randomly allocated to either the FH or the NG group. They were asked to consecutively perform as many as 30 vessel punctures on a simulated phantom model. Quantitative metrics (time taken and number of skin and posterior-wall punctures) were recorded and compared between the two groups. The cumulative sum and moving F-test statistical methods were used to delineate the learning curves. RESULTS: There was a significantly lower rate of posterior-wall punctures in the NG group than in the FH group (15% versus 26%; p < 0.0001). Participants in the NG group also performed significantly fewer skin punctures than did those in the FH group (mean, 405 versus 515; p < 0.0001). Cumulative sum statistical method analysis showed that participants in the NG group surmounted the learning curve earlier (13 attempts; interquartile range, 10.3-17.0) than did those in the FH group (19 attempts; interquartile range, 15.0-27.5). The number of attempts to surmount the learning curve was significantly less for the FH group (7.2 versus 16 attempts; p = 0.007) when using the moving F-test. CONCLUSIONS: The NG puncture allows a greater number of trainees to cross the learning threshold and offers the advantages of fewer posterior-wall punctures and skin punctures. The use of NG puncture may result in a shorter path to proficiency, allowing trainees to attempt needle puncture earlier and with a greater degree of safety.

Neuromuscular electrical stimulation for the treatment of diabetic sensorimotor polyneuropathy: A prospective, cohort, proof-of-concept study.

OBJECTIVE: To assess a potential efficacy signal, safety and feasibility of neuromuscular electrical stimulation (NMES) therapy as an adjunct to standard care in patients with diabetic sensorimotor polyneuropathy (DSPN). METHODS: In this single-centre, prospective, cohort, proof-of-concept study, 25 patients with DSPN consented to at least one daily 30-minute NMES therapy session (Revitive® IX) for 10 weeks, with 20 patients completing the study. The primary outcome measure was nerve conductivity assessed using a nerve conduction study of the sural, superficial peroneal, common peroneal and tibial nerves at 10 weeks compared to baseline. Secondary outcomes included superficial femoral artery (SFA) haemodynamics during NMES therapy compared to rest and quality-of-life at 10 weeks compared to baseline. RESULTS: At 10 weeks, there were significant increases in sural sensory nerve action potential amplitude and conduction velocity (p < 0.001), superficial peroneal sensory nerve action potential amplitude (p = 0.001) and conduction velocity (p = 0.002), common peroneal nerve conduction velocity (p = 0.004) and tibial nerve compound muscle action potential amplitude (p = 0.002) compared to baseline. SFA volume flow and time-averaged mean velocity significantly increased (p ≤ 0.003) during NMES compared to rest. Patient-reported Michigan Neuropathy Screening Instrument scores significantly decreased (p = 0.028) at 10 weeks compared to baseline. Three unrelated adverse events occurred, and 15 participants adhered to treatment. CONCLUSIONS: NMES therapy as an adjunct to standard care for 10 weeks significantly increased lower limb nerve conductivity in patients with DSPN and may be beneficial in the treatment of DSPN.

Evaluating the diagnostic and triage performance of digital and online symptom checkers for the presentation of myocardial infarction; A retrospective cross-sectional study.

Online symptom checkers are increasingly popular health technologies that enable patients to input their symptoms to produce diagnoses and triage advice. However, there is concern regarding the performance and safety of symptom checkers in diagnosing and triaging patients with life-threatening conditions. This retrospective cross-sectional study aimed to evaluate and compare commercially available symptom checkers for performance in diagnosing and triaging myocardial infarctions (MI). Symptoms and biodata of MI patients were inputted into 8 symptom checkers identified through a systematic search. Anonymised clinical data of 100 consecutive MI patients were collected from a tertiary coronary intervention centre between 1st January 2020 to 31st December 2020. Outcomes included (1) diagnostic sensitivity as defined by symptom checkers outputting MI as the primary diagnosis (D1), or one of the top three (D3), or top five diagnoses (D5); and (2) triage sensitivity as defined by symptom checkers outputting urgent treatment recommendations. Overall D1 sensitivity was 48±31% and varied between symptom checkers (range: 6-85%). Overall D3 and D5 sensitivity were 73±20% (34-92%) and 79±14% (63-94%), respectively. Overall triage sensitivity was 83±13% (55-91%). 24±16% of atypical cases had a correct D1 though for female atypical cases D1 sensitivity was only 10%. Atypical MI D3 and D5 sensitivity were 44±21% and 48±24% respectively and were significantly lower than typical MI cases (p<0.01). Atypical MI triage sensitivity was significantly lower than typical cases (53±20% versus 84±15%, p<0.01). Female atypical cases had significantly lower diagnostic and triage sensitivity than typical female MI cases (p<0.01).Given the severity of the pathology, the diagnostic performance of symptom checkers for correctly diagnosing an MI is concerningly low. Moreover, there is considerable inter-symptom checker performance variation. Patients presenting with atypical symptoms were under-diagnosed and under-triaged, especially if female. This study highlights the need for improved clinical performance, equity and transparency associated with these technologies.