[Stents in dialysis vascular access--do they promise improved high quality prolonged access use].

UNLABELLED: The life expectancy of dialysis patients depends, to a large extent, on blood access which provides uninterrupted and efficient treatment. Dialysis access created by a direct anastomosis between artery and vein usually allows normal dialysis for many years. Blood access by a bridge graft between artery and vein functions for a much shorter time and occludes chiefly because of endothelial hyperplasia at the graft vein anastomosis. This type of fistula is created when the veins of the patient are small. During the last few years the dialysis population is increasingly composed of adult and elderly patients suffering from diabetes mellitus, hypertension, dyslipidemias and atheromatous vascular disease so that a relatively large proportion of dialysis accesses are created using a bridge graft. Since we currently do not have the knowledge of how to arrest or delay the processes which lead to access occlusion, attempts are made to implement prophylactic strategies, find stenoses and dilate them before the access fails. Up to date, controlled trials have not succeeded in proving that this method prolongs access use. These trials did not describe the use of stents following dilatation. MATERIALS AND METHODS: Between July 2002 and May 2005, 238 angiographies were performed on blood accesses including 179 angioplasties of stenoses. In sixteen patients a stent was deployed during the angioplasty. RESULTS: In ten patients dialysis was performed using the same access up to the end of the study period, an average of 43 months from the creation of the access. Three patients died with a functioning access and in three the access occluded during the period of followup. DISCUSSION: This study shows that the use of stents following angioplasty of dialysis access stenoses can improve the duration of use of accesses created through grafts.

Increased detection of early vascular abnormalities after renal biopsies by color Doppler sonography.

OBJECTIVE: The purpose of this study was to assess the frequency of abnormal vascular findings after renal biopsies as detected by color and pulsed Doppler sonography. METHODS: With both color and pulsed Doppler sonography, we examined 77 patients who underwent a renal biopsy of a native kidney. The examination was carried out before and immediately after the biopsy. A follow-up sonographic assessment was performed 24 hours later. If abnormal vascular findings were detected, the patients were reexamined after 2 weeks or even for a longer period. RESULTS: Tissue samples suitable for histologic diagnosis were obtained in 94% of the biopsies. In 17 of 77 patients, changes were observed in the color and pulsed Doppler examination immediately after the biopsy. A small localized flow disturbance was diagnosed in 10 kidneys, and a color tract was seen in 7. In 1 case, this tract was associated with a small localized flow disturbance. In 2 other patients, a localized flow disturbance was detected only in the examination performed 24 hours after the biopsy. Eight of the 10 flow disturbances diagnosed immediately after the biopsy and all tracts were not visible at the 24-hour follow-up examination. All these vascular findings were undetectable on sonographic examination without color and pulsed Doppler imaging. CONCLUSIONS: The results indicate that vascular lesions, detectable with color and pulsed Doppler sonography, are not rare findings early after renal biopsies. These vascular findings show a high rate of spontaneous resolution within the first 24 hours.