[Vascular ultrasonography in the preparation and surveillance of arteriovenous fistula: a monocentric experience].

Creating an arteriovenous fistula (AVF) is complicated by the gradual increase in the average age of patients initiating chronic haemodialysis treatment and by the greater prevalence of pathologies that impact the cardiovascular system. In the past, the choice of which vessels to use for the creation of the AVF was essentially based on the physical examination of the upper limbs. Current international guidelines suggest that a colour doppler ultrasound (DUS) should be performed to complete the physical examination. Similarly, vascular ultrasound is fundamental in the post-operative phase for appropriately monitoring the access. We have conducted a retrospective analysis on the use of DUS in clinical practice in our centre, in order to determine the repercussions on vascular access survival. To this end, we identified three phases, according to the methods that were used for pre-operative vascular evaluation and monitoring of the AVF, that saw the progressive integration of clinical and ultrasound parameters. The analysis of the data highlighted a statistically significant higher rate of survival for all vascular accesses, evaluated as a whole, and for distal AVFs, in the third phase, despite a greater percentage of patients over 75 (48% vs 28%). In conclusion, we believe that an approach integrating clinical and ultrasound evaluation is indispensable to identify the most suitable AVF site and guarantee its efficiency over time.

Survival and complications of arteriovenous fistula dialysis access in an elderly population.

PURPOSE: In recent years, the number of elderly uremic patients who commence renal replacement therapy has increased. A retrospective review assessed the survival rate and incidence of complications in elderly patients with an arteriovenous fistula (AVF) created between January 2000 and August 2008. METHODS: A total of 78 patients, 48 men and 30 women aged ≥75 with a mean age of 82.5±7.5, commenced hemodialysis therapy during the period under consideration; 31% were diabetic and all had a LVEF ≥30%. For this group of patients, 90 AVF were created: 41 distal AVF (45%), 32 proximal AVF (35%), 13 midarm AVF (15%), and four AV grafts (5%). RESULTS: The survival rate of the AVF was 76% at 12 months and 71% at 24 months. A total of 47 patients with functioning AVF (60%) died during the study period. There were 18 cases of thrombosis (20%). No significant local or systemic complications occurred. CONCLUSIONS: Several aspects should be highlighted: pre-operative color-flow duplex scanning, timing of the creation of the AVF and placement of the AVF as distal as possible.The creation of AVF in elderly patients is a choice supported by the opinion that patients with tunneled central venous catheters have higher mortality rates than those with AVF. In summary, choosing vascular access sites to be created in elderly patients is no different than for younger patients-an AVF remains the gold standard.

Residual renal function and nutrition in young patients on chronic hemodialysis.

Residual renal function (RRF) has been associated with a better nutritional status in adult patients on chronic dialysis, but there is as yet no data available for young patients on chronic hemodialysis (HD). We have retrospectively analyzed 3-day dietary reports and simultaneous urea kinetic monitoring data (n = 179) of 30 children, adolescents and young adults on chronic HD. The protein catabolic rate (PCR) was calculated and normalized by body weight (nPCR). The HD dialysis dose (Kt/VHD), RRF (calculated by urea clearance, Ku, and expressed as residual Kt/V) and total Kt/V (Kt/Vtot) were evaluated. In all patients, nPCR was correlated with dietary protein intake (nDPI) (p < 0.0001) and Kt/Vtot (p < 0.0001) but not with Kt/VHD (p = 0.11). In patients with RRF, Ku was associated with nPCR (p < 0.0001), while Kt/VHD was not (p = 0.10), and nPCR was higher than in patients without RRF (1.46 +/- 0.41 vs. 1.03 +/- 0.33 g/kg/day; p < 0.0001). Patients on recombinant growth hormone (rhGH) treatment showed higher nPCR values than those without rhGH (1.34 +/- 0.41 vs. 1.01 +/- 0.39 g/kg/day; p < 0.0001). In a multiple regression model including age, rhGH treatment, RRF, Kt/Vtot and Kt/VHD, and nPCR showed the best correlation with RRF (beta = 0.128; p < 0.0001). In conclusion, in children, adolescents and young adults on chronic HD treatment, RRF positively affects nutrition independently of HD efficiency and rhGH treatment.

[The role of intraoperative parathyroid hormone assay in the surgical management of hyperparathyroidism]. / Il ruolo del dosaggio del PTH intraoperatorio nella terapia chirurgica dell'iperparatiroidismo.

BACKGROUND: Intraoperative parathyroid hormone (iPTH) assay (QPTH) in combination with preoperative localization, permits a less invasive operative approach in the treatment of hyperparathyroidism. A 50% reduction of the intraoperative PTH level, mesured within 15 minutes with an immunochemestry system of III generation (ICMA), shows the completeness of the hypersecretive tissues surgical removal. PATIENTS AND METHODS: From June 2003 to December 2005 a series of 39 patients underwent target parathyroidectomy with intraoperative parathyroid hormone assay for parathyroid disease. Intraoperative PTH was measured before, 5-10 and 20 minutes after parathyroidectomy. 79.5% of patients had secondary hyperparathyroidism, 29.5% had primary disease. In 38 patients (97,4%) the intraoperative PTH levels declined more than 70% and in only one patient (2,6%) intraoperative PTH levels declined less than 50%. RESULTS AND CONCLUSIONS: QPTH has deeply modified the surgical approach to the treatment of hyperparathyroidism. Intraoperative measurement of iPTH is useful in prediction the complete removal of all parathyroid tissue after surgery for parathyroid disease, thus avoiding persistence or recurrence of disease and surgical failures. In well-studied cases QPTH can be considered a valid alternative to the intraoperative hystological examination.