Evaluation of arteriovenous fistula for hemodialysis with a new generation digital stethoscope: a pilot study.

BACKGROUND AND AIMS: The management of complications of arteriovenous fistula (AVF) for hemodialysis, principally stenosis, remains a major challenge for clinicians with a substantial impact on health resources. Stenosis not infrequently preludes to thrombotic events with the loss of AVF functionality. A functioning AVF, when listened by a stethoscope, has a continuous systolic-diastolic low-frequency murmur, while with stenosis, the frequency of the murmur increases and the duration of diastolic component decreases, disappearing in severe stenosis. These evidences are strictly subjective and dependent from operator skill and experience. New generation digital stethoscopes are able to record sound and subsequently dedicated software allows to extract quantitative variables that characterize the sound in an absolutely objective and repeatable way. The aim of our study was to analyze with an appropriate software sounds from AVFs taken by a commercial digital stethoscope and to investigate the potentiality to develop an objective way to detect stenosis. METHODS: Between September 2022 and January 2023, 64 chronic hemodialysis (HD) patients were screened by two blinded experienced examiners for recognized criteria for stenosis by Doppler ultrasound (DUS) and, consequently, the sound coming from the AVFs using a 3 M™ Littmann® CORE Digital Stethoscope 8570 in standardized sites was recorded. The sound waves were transformed into quantitative variables (amplitude and frequency) using a sound analysis software. The practical usefulness of the core digital stethoscope for a quick identification of an AVF stenosis was further evaluated through a pragmatic trial. Eight young nephrologist trainees underwent a simple auscultatory training consisting of two sessions of sound auscultation focusing two times on a "normal" AVF sound by placing the digital stethoscope on a convenience site of a functional AVF. RESULTS: In 48 patients eligible, all sound components displayed, alone, a remarkable diagnostic capacity. More in detail, the AUC of the average power was 0.872 [95% CI 0.729-0.951], while that of the mean normalized frequency was 0.822 [95% 0.656-0.930]. From a total of 32 auscultations (eight different block sequences, each one comprising four auscultations), the young clinicians were able to identify the correct sound (stenosis/normal AVF) in 25 cases, corresponding to an overall accuracy of 78.12% (95% CI 60.03-90.72%). CONCLUSIONS: The analysis of sound waves by a digital stethoscope permitted us to distinguish between stenotic and no stenotic AVFs. The standardization of this technique and the introducing of data in a deep learning algorithm could allow an objective and fast method for a frequent monitoring of AVF.

[A case of Anderson-Fabry disease: a multidisciplinary approach for diagnosis and follow up].

Fabry disease (also known as Anderson-Fabry disease, angiocheratoma corporis diffusum, diffuse angiocheratoma) is a rare tesaurismosis linked to the deficiency of the lysosomal enzyme alpha-galactosidase A, required for the physiological catabolism of glycosphingolipids. The related clinical signs show a multisystemic feature and define a degenerative and disabling pathology, whose approach requires a close multidisciplinary specialist collaboration. Currently, the renewed interest in the disease is aimed at the need to provide an early diagnosis, in order to early begin the enzyme replacement therapy and to slow down or avoid the establishment of irreparable organ damage. For this reason, the diagnostic suspicion becomes crucial and arises from the careful observation and research of the symptoms, together with the anamnesis and the overall clinical evaluation of the patient.

[An unusual presentation of Amyloidosis AL].

We describe the case of a 74-year-old man admitted to our Nephrology Unit with nephrotic syndrome and mild kidney disease. A complete panel of laboratoristic and instrumental tests did not provide useful information for diagnosis. No specific signs or symptoms suggested the presence of AL amyloidosis. As a matter of fact, diagnosis was reached thanks to the hystopathologic examination of renal tissue and bone marrow, since the associated B-cell lymphoproliferative disorder had not revealed itself through serum and urine electrophoresis and immunofixation. This recent case provides the opportunity to review about the disease and to revaluate the renal biopsy as a first line exam in a clinical context where laboratoristic and instrumental tests offer us poor information.

Current evidence on the use of anti-RAAS agents in congenital or acquired solitary kidney.

RATIONAL: The inhibition of renin-angiotensin-aldosterone system (RAAS) is a major strategy for slowing the progression of chronic kidney disease (CKD). The utility of anti-RAAS agents in patients with congenital or acquired solitary kidney is still controversial. OBJECTIVE: A systematic literature review was conducted. MAIN FINDINGS: The conclusions of the few available studies on the topic are homogeneously in agreement with a long-term reno-protective activity of anti-RAAS drugs in patients with solitary kidney, especially if patients are hypertensive or proteinuric. However, angiotensin 2 (ANG2) levels permit a functional adaptation to a reduced renal mass in adults and is crucial for sustaining complete kidney development and maturation in children. A hormonal interference on ANG2 levels has been supposed in women. Consequently, at least in children and women, the use of ARBs appears more appropriate. Principle conclusions: Available data on this topic are limited; however, by their overall assessment, it would appear that anti-RAAS drugs might also be reno-protective in patients with solitary kidney. The use of ARBs, especially in children and in women, seems to be more appropriate. However, more experimental data would be strictly necessary to confirm this hypothesis.