Drug-eluting metallic stents in urology

Abstract

Drugeluting metal stents (DESs) have been extensively used in coronary and vascular disease. This type of stents has been proven to provide significantly lower restenosis rates due to the reduction of neo-intimal hyperplasia in comparison to the traditionally used bare metal stents (BMSs). The latter stents have been evaluated for more than a decade in urological practice in an attempt to provide permanent relief of urethral or ureteral obstruction. Although the initial results were promising, long-term experience revealed significant complications, which are mainly attributed to stent-related hyperplastic reaction compromising stent patency. The favorable experience of vascular DESs led to the application of DESs in both the urethra and ureter of animal models. These experimental results demonstrated a reduction of hyperplastic reaction of DESs in comparison to BMSs. Nevertheless, clinical data are currently not available. Considering the fact that DESs are under continuous development, the use of DESs in urology holds promise for the future and seems to be an intriguing field.

Keywords: Drug-eluting; metal stent; optical coherence tomography; paclitaxel; sirolimus; ureteral stent; zotarolimus.

Figure 1

(a) Optical coherence tomography image of rabbit ureter stented by drug-eluting stent. Notice the presence of the stent struts which appear as an illuminating point accompanied by a backshadow. The yellow line shows the thickness of the urothelium.(b) Optical coherence tomography image of the other ureter of the same animal, stented by bare metal stent of. The yellow line shows the thickness of the urothelium, which in this case is obviously higher