[Steno-obstructions of haemodialytic FAV: new aspects of endovascular treatments]. / Trattamento endovascolare delle complicanze steno-ostruttive delle fistole artero-venose emodialitiche: nuovi aspetti di intervento con radiologia interventistica.

Angioplasty is the usual method for the treatment of stenosis of arteriovenous fistulas for hemodialysis, along with fibrinolysis and thrombus aspiration. We evaluated the efficacy and safety of interventional radiology procedures in the treatment of stenosis or occlusion of arteriovenous fistulas. One hundred thirteen patients suffering from malfunction of arteriovenous fistulas underwent interventional radiological procedures (140 treatments). In all patients color-Doppler was performed beforehand. Stenosis at the site of the fistula was found in all patients and was treated with percutaneous transluminal angioplasty (PTA); stenosis at the anastomosis site was found in 63 cases and was treated by angioplasty with a microcatheter. In 40 patients suffering from recent thrombotic occlusion, locoregional thrombolysis and PTA were necessary. Technical and clinical success was achieved in 107 patients (94.6%); in 1 of 6 unsuccessful treatments the procedure had to be interrupted due to the rupture of a vein. Follow-up exams demonstrated primary patency in 92.5%, 71.9% and 49.5% of patients at 6 months, 1 year and 2 years, respectively. In 19 patients (17.7%) hemodynamically significant restenosis was observed, which was treated with multiple PTAs (27 treatments, only 1 of which with a negative outcome), resulting in a 94.2% success rate; only 1 patient had to undergo a fourth PTA. The overall patency rate was 95%, 87.2%, 62.3% at 6 months, 1 year and 2 years, respectively. In our experience immediate success and excellent patency rates were observed, which persisted in the medium and long term. PTA, with thrombolysis and thromboaspiration, is the treatment of choice in cases of malfunctioning arteriovenous fistulas. PTA should always be attempted before making a new surgical access in order to preserve the vascular tree.

[Use of venae comitantes in the creation of arteriovenous fistulas: retrospective evaluation of our experience]. / L'utilizzo della vena comitans nel confezionamento delle fistole artero-venose: valutazione retrospettiva della nostra esperienza.

In order to estimate the outcome of arteriovenous fistula (AVF) for hemodialysis, we reviewed our experience in the construction of AVFs using the venae comitantes in patients without an adequate superficial venous vascular territory. The study included 34 patients affected by end-stage renal disease in whom an AVF was created using the deep venous system. In 26 of them we performed an anastomosis between the brachial artery and its vena comitans. Immediate success, defined by the presence of a thrill at the end of the anastomosis, was obtained in 84%, while primary failure of the AVF (immediate postoperative failure) occurred in 3 patients (12%). Early failure, defined as failure within 6 weeks of AVF placement, occurred in 4% of patients. Of the 22 patients with a functioning AVF, 8 (36%) subsequently requested a second operation to bring the fistula to the surface. Some of these involved the placement of synthetic grafts for better accessibility. The primary patency of the AVFs was equal to 64%, while the patency after a second intervention was 91%. Among the 26 AVFs created with venae comitantes, total patency at 50 weeks was 62%. Our experience with the placement of prosthetic grafts draining into the venae comitantes has not provided encouraging results. We believe that for adequate exploitation of venae comitantes it is important to use native veins that have to meet specific anatomical and functional requirements. The creation of an AVF with a native vein, taking advantage of the deep venous system, is feasible under the right circumstances.

[Central venous stenting in patients on hemodialysis: review of our case series and long-term follow-up]. / Stenting venoso centrale in pazienti emodializzati: revisione della nostra casistica e follow-up a distanza.

Aims of the study was validate the venous stenting technique as the treatment of choice in patients affected by stenosis or occlusion of the central venous area. To evaluate the long-term patency of placed stents in our series and to detect factors predisposing to restenosis. Twenty-three hemodialyzed patients were treated by PTA or placement of a metallic self-expandable stent in the central venous area because of occlusion or severe stenosis caused by repeated central venous access puncture for Port-A-Cath or pacemaker placement. All patients were examined every 3 months after treatment by clinical examination and color-Doppler ultrasound. Stents were placed with success in all cases but one, where it was impossible to get past the occlusion. Restenosis was observed in 12 cases at 4 to 12 months (average 8 months). Intrastent restenoses were treated with success by PTA alone and stent placement in 4 cases. A new restenosis was observed in 4 retreated patients in whom the stent was short or angled. In the other patients restenosis was attributable to disregard of anticoagulant therapy. In conclusions, the availability of new devices and dedicated stents is still necessary. There is a limited relationship between patency and wrong stent placement. Patients undergoing stenting should be controlled by clinical examination and color-Doppler ultrasound in hospitals where skilled interventional radiologists are available.

[The kidney in dysproteinemia]. / Il rene nelle paraproteinemie.

Several renal diseases are associated with the dysproteinemias, and their pathogenesis is related to paraprotein deposits in the kidney: light chains can affect the kidney by a direct toxic effect on tubular cells, or by intratubular or tissue precipitation. Multiple myeloma (MM) is the most prevalent dysproteinemia, and the spectrum of associated renal diseases includes myeloma kidney (cast nephropathy), amyloidosis and monoclonal immunoglobulin deposition disease (MIDD). Renal failure is seen in approximately 50% of patients with MM at diagnosis, most frequently attributed to myeloma kidney. Renal function can recover in more than half the patients by prompt rehydration with intravenous fluids, to achieve a urine flow of >3 l/day, and by treating the hypercalcemia. Plasma exchange in combination with corticosteroids is suggested in patients with rapidly progressive renal failure. When renal failure is associated with MIDD or amyloidosis, renal function recovery is reduced to 10%, and patient survival is related to the entity of extrarenal tissue distribution of paraprotein deposits. Dialysis should be offered to patients with end-stage renal disease. High dose chemotherapy and autologous stem cells transplantion (SCT) is recommended in patients who do not have severe co-morbidities.

End-stage renal failure from renal amyloidosis of the AA type associated with giant lymph node hyperplasia (Castleman's disease).

A case of end-stage renal failure caused by renal amyloidosis of the AA type is reported. No chronic disease responsible for the deposition of reactive amyloid was detected until giant lymph node hyperplasia of the angiofollicular type was identified in a mediastinal mass. Amyloid was found within the tumour mass and was characterized by immunochemistry with monoclonal antibodies to be of the AA type. Castleman's disease should be added to the list of chronic diseases endangering renal function by inducing the production and tissue deposition of secondary (AA) amyloid.

Effects of synthetic salmon calcitonin administration on gastrin, immunoreactive insulin and growth hormone release after protein meal in uremic patients.

Recent studies indicate that calcitonin inhibits, in man, the secretion of several hormones such as gastrin, insulin, growth hormone. There are no reports about this effect in uremic patients in which frequently calcitonin, gastrin, growth hormone, and insulin response to glucose administration is increased. A comparative study of the effects of synthetic salmon calcitonin infusion (50 U iv) on gastrin, growth hormone and insulin release protein meal (250 g of boiled lean beef) in 10 uremic patients undergoing hemodialysis and in 10 normal subjects was performed. Insulin and growth hormone response to protein meal was inhibited by calcitonin both in normal and uremic subjects. Gastrin response instead was inhibited only in normal subjects. These findings indicate that in uremic patients the inhibitory effect of calcitonin on insulin and growth hormone secretion is still present. The lack of evident inhibitory effect on gastrin release could be related to persistent hypergastrinemia because of the increased half life of the hormone which could mask acute changes of secretion.

[Malate dehydrogenase and glutamate dehydrogenase activity modification in livers of rats exposed to a double stress (dry heat - fasting). I]. / Modificazioni dell'attivita' della malico-deidrogenase e della glutammato-deidrogenasi nel fegato di ratti sottoposti a duplice stress (caldo secco - digiuno). Nota I.

We have studied MDH and GLDH behaviour in liver homogenized of rats exposed to double stress (dry heat and starvation) for 24 hours respectively. Both enzyme showed a statistically significant activity increase, either after 24 and 72 hours. Such an increase is affected mainly by starvation. This behaviour reflects the metabolic needs of organism, related to increased energetic requirements.

[Modification of malate dehydrogenase and glutamate dehydrogenase in hearts of rats exposed to a double stress (dry heat - fasting). III]. / Modificazioni dell'attivita' della malico-deidrogenasi i della glutammato-deidrogenasi nel cuore di ratti sottoposti a duplice stress (caldo secco - digiuno). Nota III.

MDH and GLDH activity modifications have been studied in heart homogenized of rats exposed to double stress (dry heat and starvation). MDH activity shows statistically significant variations only after 72 hours. This induces to suspect a decrease of energetic metabolism due to a probable substratum lack. GLDH activity shows a statistically significant decrease after 24 hours, and this decrease increases after 72 hours. This behaviour could be explained by an acclimatization reaction of such an amount to delete the hunger effect on protein catabolism.