A systematic review of prediction models on arteriovenous fistula: Risk scores and machine learning approaches.

OBJECTIVE: Failure-to-mature and early stenosis remains the Achille's heel of hemodialysis arteriovenous fistula (AVF) creation. The maturation and patency of an AVF can be influenced by a variety of demographic, comorbidity, and anatomical factors. This study aims to review the prediction models of AVF maturation and patency with various risk scores and machine learning models. DATA SOURCES AND REVIEW METHODS: Literature search was performed on PubMed, Scopus, and Embase to identify eligible articles. The quality of the studies was assessed using the Prediction model Risk Of Bias ASsessment (PROBAST) Tool. The performance (discrimination and calibration) of the included studies were extracted. RESULTS: Fourteen studies (seven studies used risk score approaches; seven studies used machine learning approaches) were included in the review. Among them, 12 studies were rated as high or unclear "risk of bias." Six studies were rated as high concern or unclear for "applicability." C-statistics (Model discrimination metric) was reported in five studies using risk score approach (0.70-0.886) and three utilized machine learning methods (0.80-0.85). Model calibration was reported in three studies. Failure-to-mature risk score developed by one of the studies has been externally validated in three different patient populations, however the model discrimination degraded significantly (C-statistics: 0.519-0.53). CONCLUSION: The performance of existing predictive models for AVF maturation/patency is underreported. They showed satisfactory performance in their own study population. However, there was high risk of bias in methodology used to build some of the models. The reviewed models also lack external validation or had reduced performance in external cohort.

Dialysis nurses' knowledge, attitude, practices, and self-efficacy regarding vascular access care: A multicenter cross-sectional survey in Singapore.

BACKGROUND: Dialysis nurses play a pivotal role in the management of vascular access (VA), physician-patient liaison, and patient education for hemodialysis patients. This multicenter study aims to review the dialysis nurses' knowledge, attitude, practice, and self-efficacy toward providing care for patients' VA. METHODS: A multi-centered study was conducted using a self-administered survey. Nurses from 47 Singapore dialysis centers (five hospital-based and 42 community-based) providing hemodialysis were invited to participate on a voluntary and anonymous basis from April to November 2022. The survey consists of nurses' knowledge on VA (10 items), attitude on VA care (six items), usual practices (seven items), and self-efficacy in VA cannulation and management (six items). The total scores for the knowledge, attitude, and self-efficacy components were 50, 30, and 30 respectively. The instrument has been validated in a pilot study. RESULTS: In total, five hundred sixteen dialysis nurses participated the survey. The mean (±SD) knowledge score of the participants toward VA care was 30.0 (±8.1) over a total score of 50. The means (±SD) of their attitude and self-efficacy scores were 24.4 (±4.1) and 24.2 (±3.1) over 30 respectively. The majority of the nurses (84.1% in hospital-based centers and 98.9% in community-based centers) conducted patient education in some aspects of VA care. The percentage of nurses indicated need for referral to access specialists due to various abnormalities varied significantly between the hospital-based and community-based settings. In the multivariable linear regression analysis, longer working experience was a significant factor for higher knowledge score (B = 0.26; p = 0.001), attitude score (B = 0.08; p = 0.01), and self-efficacy score (B = 0.34; p < 0.001). CONCLUSION: Dialysis nurses in Singapore have satisfactory knowledge, practice, and self-efficacy on VA care. The majority of them expressed positive opinions toward the VA-related training they received, new technologies, and communications. The identified knowledge and practice gaps could be incorporated into the future training programs.

A portable optical pulsatile flowmetry demonstrates strong clinical relevance for diabetic foot perfusion assessment.

We present a robust, cost-effective (<2000 USD), and portable optical diffuse speckle pulsatile flowmetry (DSPF) device with a flexible handheld probe for deep tissue blood flow measurement in the human foot as well as a first-in-man observational clinical study using the proposed optical device for tissue ischemia assessment and peripheral artery disease (PAD) diagnosis. Blood flow in tissue is inherently pulsatile in nature. However, most conventional methods cannot measure deep tissue-level pulsatile blood flow noninvasively. The proposed optical device can measure tissue-level pulsatile blood flow ∼6 mm underneath the skin surface. A new quantitative tissue perfusion index (TPIDSPF) based on frequency domain analysis of the pulsatile blood flow waveform is defined to assess tissue ischemia status. Through a clinical study involving 66 subjects, including healthy individuals and diabetes patients with and without PAD, TPIDSPF demonstrated strong correlations of 0.720 with transcutaneous tissue partial oxygen pressure (TcPO2) and 0.652 with toe-brachial index (TBI). Moreover, among the three methods, TPIDSPF demonstrated the highest area under the curve for PAD diagnosis among diabetes patients, with a notable value of 0.941. The promising clinical results suggest that the proposed optical method has the potential to be an effective clinical tool for identifying PAD among the diabetic cohort.

Decision-making for early major amputation in selected diabetic foot ulcer patients with peripheral vascular disease.

Objective: To estimate the costs from delaying major amputation in patients with concurrent diabetic foot ulcer and peripheral vascular disease. We seek to model economic benefits from saved costs from promoting timely major amputations among these patients. Methods: Retrospective modeling using data from National University Hospital, Singapore. We identified patients who might have delayed major amputations by applying a hierarchical clustering algorithm. We then modeled the transitions of all patients over time with a Markov process using a number of relevant health states to enable estimation of cost outcomes. We next summarized the expected changes to the bed days used and cost outcomes arising from reassigning some patients who may have had a delayed amputation to timely amputation. The findings from the sample were scaled to reflect national incidence rates for this disease for the years 2014-2019 in Singapore. Results and Conclusions: Nine of the 137 patients (6.57%) would be suitable for a major amputation at 3 months, yet in reality, their amputation was delayed. Based on this, and assuming a timely amputation is done for the entire population of patients in Singapore we expect annual savings of 264,791 bed days and $211 million in costs. These findings are preliminary and uncertain. The value of this paper is to show a method for estimating outcomes, report the findings from a small sample, and stimulate future research. New cohort studies might be designed to capture a wider range of outcomes and recruit a larger sample of individuals.

The autophagy-lysosome pathway: a potential target in the chemical and gene therapeutic strategies for Parkinson's disease.

Parkinson's disease is a common neurodegenerative disease with movement disorders associated with the intracytoplasmic deposition of aggregate proteins such as α-synuclein in neurons. As one of the major intracellular degradation pathways, the autophagy-lysosome pathway plays an important role in eliminating these proteins. Accumulating evidence has shown that upregulation of the autophagy-lysosome pathway may contribute to the clearance of α-synuclein aggregates and protect against degeneration of dopaminergic neurons in Parkinson's disease. Moreover, multiple genes associated with the pathogenesis of Parkinson's disease are intimately linked to alterations in the autophagy-lysosome pathway. Thus, this pathway appears to be a promising therapeutic target for treatment of Parkinson's disease. In this review, we briefly introduce the machinery of autophagy. Then, we provide a description of the effects of Parkinson's disease-related genes on the autophagy-lysosome pathway. Finally, we highlight the potential chemical and genetic therapeutic strategies targeting the autophagy-lysosome pathway and their applications in Parkinson's disease.