Restenosis after stenting of atherosclerotic renal artery stenosis: Is there a rationale for the use of drug‐eluting stents?

Abstract

Percutaneous stent-angioplasty has become an accepted therapy for the treatment of atherosclerotic renal artery stenosis (RAS) because of higher acute and long-term success rates compared with balloon angioplasty alone. Restenosis rates after successful renal stent placement vary from 6 to 20% and depend mainly on the definition of restenosis and the vessel diameter of the renal artery or stent. We recommend that restenosis should be defined as >70%. The safety and efficacy of drug-eluting stents for the treatment of RAS is poorly defined. The currently partially published GREAT study (Palmaz Genesis peripheral stainless steel balloon expandable stent: comparing a sirolimus-coated vs. a bare stent in REnal Artery Treatment) examined the effect of a sirolimus-coated stent on restenosis rate in 102 patients and found a relative risk reduction of angiographic binary in-stent restenosis by 50% (7% versus 14%, P = ns). Given the lack of outcome data, the considerable expenses associated with drug-eluting stents, morbidity, and cost associated with prolonged dual antithrombotic therapy, the use of drug-eluting stents in RAS should be restricted to clinical trials. This is a review on restenosis rate following renal stenting, its definition, and the potential use for implantation of a drug-eluting stent in RAS, which so far for this indication is not yet commercially available.

Sirolimus-Eluting Biodegradable Poly-l-Lactide Stent for Peripheral Vascular Application: A Preliminary Study in Porcine Carotid Arteries

“…Thus far, incorporation of Paclitaxel or Dexamethasone to the polymeric stent has been performed with promising results regarding restenosis after implantation in porcine coronary and iliac arteries [24,25]. According to the beneficial effects of Sirolimus eluting metal stents in clinical settings, we hypothesized, that incorporated Sirolimus suppresses the inflammation process around the PLLA struts [2][3][4][5][6][7][8][9]. The common carotid artery was used as a model in these animals but the findings may also be applicable to other arterial vessels, particularly small vessels where restenosis is a major issue.…”

“…They have substantially improved long-term outcomes for restenosis after coronary implantation [2][3][4]. They are currently under clinical investigation for the superficial femoral artery [5,6], and promising results of single-centers have been achieved in other arteriosclerotic lesions [7][8][9]. Furthermore, sirolimus eluting metallic stents were effective in reducing neointimal formation in porcine carotid arteries in a short-term study [10].…”

Ultrasound velocity criteria for renal in-stent restenosis

“…Published studies for DUS criteria for renal ISR have used PSV, RAR, resistive index, or a combination of these to assess ISR, [21][22][23] whereas others used differences in resistive index, 23 22 on the other hand, showed a drop in accuracy in the detection of renal ISR if the velocity criteria for nonstented renal artery was applied, and further suggested lowering PSV (from 180 to 144 cm/s) and RAR (from 3.5 to 2.53 ) to increase sensitivity and specificity to detect ISR.…”

The role of percutaneous revascularization for renal artery stenosis

“…115,119 Although there has been interest in drug-eluting stents in the renal arteries, there is currently no data supporting their use in limiting restenosis, and one study showed marginal differences in restenosis rates between drug-eluting and bare metal stents. 120 Distal embolization may occur at the time of aortic catheterization, PTRA or renal artery stent placement. Although clinically apparent distal embolization is uncommon during RAI (0-3%), embolization of atheroemboli, acute thromboemboli, or cholesterol emboli may lead to leg or foot pain ('blue toe syndrome'), bowel ischemia, or skin injury ('livedo reticularis'), or a decline in renal function.…”