[Midarm arteriovenous fistula: single-center experience]. / Fistola artero venosa midarm: esperienza monocentrica.

In uremic patients on hemodialysis, a first vascular access using native vessels tailored into a radiocephalic arteriovenous fistula (AVF) on the wrist is the gold standard in vascular access quality. However, among the uremic population the percentage of older patients affected by diabetes or by severe generalized vascular disease is growing. In these patients distal radiocephalic AVFs often have a limited survival. This induced us to design a technique for tailoring vascular accesses at a proximal site. In the past two years (2006-2007) we created 19 AVFs at the midarm position (midarm AVF) using the proximal section of the radial artery. Midarm AVF was the second choice in 70% of patients after failure of a distal AVF and the first choice in 30% of patients. The survival of this type of access has been excellent. We have registered only one thrombosis after 6 months. In four cases access was interrupted because of the death of the patients. The remaining 14 accesses are working perfectly well. Our experience leads us to conclude that midarm AVF is not only an important intermediate step after the failure of a distal AVF and before the application of a proximal AVF, but in a population of patients with diabetes and generalized vascular disease it should probably be proposed as the AVF of choice.

[Experience in the surveillance of arteriovenous fistula in Verbania, Italy]. / Esperienza di Verbania nella sorveglianza delle fistole arterovenose.

One hundred forty-five patients are receiving renal replacement therapy at our center: 127 are on hemodialysis, 18 on peritoneal dialysis. From 2000 through 2005 a total of 215 arteriovenous fistulas (57% distal, 31% proximal, 12% prosthesis) were created. After some time we felt the necessity to design a vascular access surveillance system because the uremic population was increasingly constituted by aged people, including many diabetics and people suffering from hypertension with generalized vascular disease. The system comprised objective examination of the access at every dialysis session; kinetic Kt/V every 3 months; and a recirculation test (GIT) every 6 months. When there were anomalies in one of the above test results, color Doppler was performed. Detection of major stenosis with altered velocity parameters was a clear indication for angiography, possibly followed by angioplasty (PTA). In the indicated period, 15 patients underwent this procedure, and PTA was performed in all of them, often with placement of an endovascular stent. The results showed a survival of 12 months in 85% of patients and 18 months in 71% of patients. On the whole these data are comparable with others in the medical literature. The incidence of restenosis can be considered acceptable: it occurred in 3 cases out of 15 and could be corrected by PTA. In conclusion, PTA plus stent implantation is a valid method allowing quick and reliable correction of stenosis; a vascular access surveillance protocol and color Doppler imaging allow patient selection for angiography. PTA is to be considered an intermediate phase in stenosis correction before suggesting a new vascular access intervention to the patient.

Verapamil versus amlodipine in proteinuric non-diabetic nephropathies treated with trandolapril (VVANNTT study): design of a prospective randomized multicenter trial.

Angiotensin converting enzyme inhibitors (ACEI) are the most effective antiproteinuric agents and should be used as first-line drugs in both diabetic and non-diabetic proteinuric nephropathies. The role of calcium channel blockers (CCB) is much more controversial. In diabetic patients verapamil and diltiazem seem more effective than dihydropyridines in reducing urinary protein excretion, and have additive effects with ACEI, but little is available on chronic treatment of non-diabetic nephropathies for non-dihydropyridine CCBs. To test whether the combination of verapamil 180 mg or amlodipine 5 mg with trandolapril 2 mg reduces urinary protein excretion more than trandolapril 2 mg alone, we planned a prospective, randomized, double-blind, multicenter trial. The secondary aims are to evaluate the effects of both treatments on the selectivity of proteinuria and check their safety. Consecutive patients aged between 18 and 70 years with non-diabetic proteinuria > or =2 g/24 h and plasma creatinine < 3 mg/dl or creatinine clearance > or = 20 ml/min are asked to participate. After a four-week run-in during which previous antihypertensive therapy is withdrawn, a single dose of trandolapril 2 mg is given once a day in open conditions for four weeks. At the end of this period patients are randomly assigned to receive once a day, in a double blind fashion, either trandolapril 2 mg and verapamil 180 mg [plus a placebo], or trandolapril 2 mg plus amlodipine 5 mg. They are monitored after one, two, five and eight months.