The Pre-dilatation of vessels: A simple method to recruit small caliber veins for creating distal fistulas.

Maturation failure remains a major clinical problem of distal arteriovenous fistula (AVF). Early failure (EF) is associated with the small size of the veins. For about 10 years we have used in more than 1000 fistulas, the Vessels Pre-Dilatation (VPD) to increase the recruitment of small veins for creating distal AVFs. The purpose of this study is to highlight if the VPD can reduce the incidence of EF or failure to mature (FTM) in AVFs created with small veins. Data of all the consecutive patients directly admitted to our Department for their first distal AVF from January to December 2019 were collected. The patients were divided in two groups, one with a vein diameter after the tourniquet ⩽2.0 mm (G1) and one >2 mm (G2). Both in G1 then in G2 the vessels had undergone VPD. Immediate failure (IF), EF, FTM, delayed or arrested maturation rate (DAM), unassisted AVFs and matured AFVs were evaluated. The patients recruited totalled 104, 37 in G1, and 67 in G2. The two groups were homogeneous in age, incidence of diabetes, obesity, heart disease, peripheral vasculopathy, and race. Female were more numerous in G1 (51% vs 12%, p < 0.001). In G1 and G2 occurred respectively 3 IF versus zero (p < 0.05), 10 EF (29%) versus 6 (9%) (p < 0.05), 6 DAM (16%) versus 6 (9%), 21 unassisted AVFs (57%) versus 57 (85%) (p < 0.01). Dividing the patients into groups of unassisted and assisted AVFs, female and low vein diameter are more represented in the assisted group. There were 32 matured AVFs (86%) in G1 and 65 (97%) in G2. In order to increase the incidence of the distal AVF, the PDV allows to include small veins. However, more patients require further interventions to achieve maturation of the fistula.

[A case of Xanthinuria in a patient with marked hypouricemia]. / Un caso di xantinuria in una paziente con marcata ipouricemia.

Xanthinuria is a rare autosomal recessive disorder associated with a deficiency of xanthine oxidoreductase (XOR), which normally catalyzes the conversion of hypoxanthine to uric acid. The effects of this deficit are an elevated concentration of hypoxanthine and xanthine in the blood and urine, hypouricemia, and hypouricuria. The deficit in XOR can be isolated (type I xanthinuria) or associated with a deficit in aldehyde oxidase (type II xanthinuria) and sulfite oxidase (type III xanthinuria). While the first two variants have a benign course, are often asymptomatic (20%), and clinically indistinguishable, type III xanthinuria is a harmful form that leads to infant death due to neurological damage. The clinical symptoms (kidney stones, CKD, muscle and joint pain, peptic ulcer) are the result of the accumulation of xanthine, which is highly insoluble, in the body fluids. We describe a case of type I xanthinuria in a 52-year-old woman who presented with hypouricemia, hypouricuria and kidney stones. The diagnosis was based on purine catabolite levels in urine and serum measured by 3 nonroutine methods: high-pressure liquid chromatography, mass spectrometry, and magnetic resonance imaging. To identify the type of xanthinuria the allopurinol test was used. We believe that these tests will facilitate the diagnosis of xantinuria especially in asymptomatic patients without the need for a biopsy of the liver or intestines, which is useful only for scientific purposes.

How to create and preserve distal fistulas in a large number of patients: the experience of a single centre.

Background: Distal arterio-venous fistula (AVF) is considered the gold standard for vascular access in hemodialysis. The aim of this retrospective study is to report our experience on two innovative techniques, Intraoperative Transluminal Angioplasty (ITA) and Vessel Pre-Dilatation (VPD). Methods: We collected data from all the consecutive patients directly admitted to our Department from January 2014 to October 2018 in order to create or repair an AVF. Early Failure (EF), Failure to Mature (FTM), Late Failure (LF), Primary and Secondary patency rate were evaluated. Results: All patients underwent VPD; of the total 647 AFVs, 128 received an ITA for the presence of suboptimal vessels. 98.3% of AVFs were located on the forearm. EF occurred in 83 cases; in 67 of these a new AVF was successfully created upstream from the previous one. LF occurred in 100 cases; of these, the access was abandoned in 32 cases and we performed a new AVF upstream from the previous one in 68 cases. FTM occurred in 57 cases, 31 of which were treated with Percutaneous Transluminal Angioplasty (PTA) whilst 26 were resolved performing a new anastomosis upstream. Primary and secondary patency at 1, 2, 3 and 4 years were, respectively, 80%, 74%, 68%, 64% and 94%, 91%, 89%, 88%. By dividing patients into an ITA group and a control group, we did not find any difference in primary and secondary patency. Conclusions: VPD and ITA could be useful to increase the incidence and the prevalence of distal AVF.

[The treatment of AKI in nephrology hospitalization: the SLE-HDF 15 litres in 10 hours].

The AKI in intensive care has been widely treated by international and national guidelines. The treatment of AKI in patients not requiring admission in Intensive Care Unit, but often hospitalized in Nephrology Unit, it is showed of less relevance. For over 5 years we have used for the treatment of AKI of patients admitted in Nephrology Unit an intermittent slow technique, implemented in approximately 600 patients with AKI for a total of about 3000 treatments. In this study we report the clinical results obtained in 100 consecutive patients referred to our Nephrology Unit from 1st January 2014. We excluded the patients with AKI and lactic acidosis by metformin, which were treated with CVVHDF. The Dialysis Protocol provides a slow low efficiency intermittent treatment called SLE-HDF (Sustained Low Efficiency Hemo-Dia-Filtration), with 10-hour duration, 1.5 L/h dialysate for a patient up to 75 kg, 2 L/h up to 85 kg, 2.5 L/h over 85 kg. Half of the dialysate was used in convention in post and half in diffusion. Endpoints were the recovery of renal function and the survival of the patient. On each patient was calculated on at least one seat, the Kt/V urea (UKt/V). Were studied 100 patients, 45 females and 55 males, with mean age 79.4 + 11 years. The weight was 74 kg + 18 kg at the start of treatment. The 65% of patients had diuresis < to 500 ml/24 hours. The causes of AKI were: 41% heart failure, 31 % AKI on MRC, 7% rhabdomyolysis, 6% Hepato-renal Syndrome, 4% sepsis, 11 % other causes. Major comorbidities were heart disease (63%), diabetes (50%), COPD (38%), age over 85 years, cancers 23, liver disease 16, hypotension requiring amine 15, sepsis 10. In total in the 100 patients, 512 treatments were performed, average 5.12 + 3.7. The mean UKt/V was 0.4 + 0.05 per session. The deaths were 43. Patients discharged were 57. Of these, 43 had a recovery of renal function. Fourteen patients have not recovered renal function and were admitted for chronic dialysis treatment. In conclusion, our protocol of SLE-HDF, which uses volumes of dialysate sharply lower than used in literature, has been shown to be effective in correcting the biochemical profile of the patient with AKI. The clinical results are considered satisfactory, having obtained the improvement in 57% of patients, considering that the 43 deaths, 10 were suffering from Hepato-cirrhosis and 13 from malignant neoplasm. Further studies are needed to confirm our findings.

Primary intraoperative transluminal angioplasty: a new approach to reduce the early failure of distal arteriovenous fistulas.

PURPOSE: About 8 years ago, we approached an intraoperative transluminal angioplasty (ITA) performed during the arteriovenous fistula (AVF) creation, to treat arterial or venous stenosis diagnosed by a preliminary ultrasound examination. Objective of this study is to validate the efficacy of ITA. METHODS: Early failure (EF) and failure to mature (FTM) were evaluated in 69 AVFs with ITA created in 58 patients in the last 3 years. In the same period, 160 patients received 188 AVFs without ITA and were considered control group. Of the two groups, age, comorbid factors, sex, primary and secondary patency rate (PR) were also analysed. RESULTS: The two groups were homogeneous for gender and age (70.4 + 11.1 years of ITA group vs. 66.3 + 14.4, p = 0.059). The incidence of diabetes, heart disease and peripheral artery disease was higher in the ITA group (43% vs. 17%, p<0.0001, 35% vs. 6%, p<0.0001 and 56% vs. 15%, p<0.0001, respectively). EF and FTM occurred in seven and eight cases in the ITA group and in 15 and 13 cases in the controls, respectively. Total failure occurred in 24% of ITA group and 14% of the controls (p = 0.2). The primary PR at 6, 12 and 24 months was 78%, 72% and 59% for ITA group and 85%, 78% and 78 % for control group (p<0.01). The secondary PR at 6, 12 and 24 months was 91%, 86% and 80% for ITA group and 95%, 95% and 92% for the controls (p<0.01). CONCLUSIONS: Our ITA approach has allowed satisfactory results in patients at a high risk of AVF failure.