Current status of infrapopliteal artery stenting in patients with critical limb ischemia

Abstract

Due to the fear that early thrombosis and late luminal loss resulting from intimal hyperplasia might impede sustained patency of small-caliber arteries, such as those of the infrapopliteal bed, stent implantation in below-knee vessels remains controversial and is generally reserved for cases with a suboptimal outcome after percutaneous transluminal angioplasty (i.e. > 50% residual stenosis, flow-limiting dissection). Although evidence starts to build, favoring the use of stenting in the tibial area, results of well-conducted randomized controlled trials have to be awaited to change this strategy. Because of diameter similarities with coronary arteries, the first stents applied in the infrapopliteal vessels were all coronary devices. Once the feasibility of the stenting approach with these coronary products was shown, device manufacturers started to develop a dedicated infrapopliteal product range. To date, a broad spectrum of stent types has been used and investigated for the given indication. This article overviews the available literature and results of different balloon-expandable (bare metal, passive coated, drug eluting), self-expanding and absorbable stent types available for below-the-knee application and gives recommendations for future device technology advancements.Keywords: Stents, ischemia, arteriosclerosis. ResumoDevido ao receio de que a trombose precoce ou a estenose tardia por hiperplasia intimal possam impedir a manutenção da perviedade em vasos de pequeno calibre, o uso de stents pós-angioplastia no leito arterial infrapoplíteo permanece controverso e geralmente é reservado aos casos de resultado subótimo após angioplastia transluminal percutânea (isto é, estenose residual > 50% ou dissecção com limitação do fluxo). Apesar de evidências começarem a favorecer o uso de stents no segmento tibial, é necessário aguardar o resultado de ensaios controlados, randomizados e bem conduzidos para mudar esta estratégia. Sendo estes vasos infrapoplíteos de diâmetro similar às artérias coronárias, os primeiros stents usados neste segmento eram todos stents coronários. Uma vez que se mostrou exeqüível o uso destes stents, a indústria iniciou o desenvolvimento de uma linha de produtos específicos ao segmento infrapoplíteo. Atualmente uma gama de stents tem sido usada e investigada para este fim. Este artigo revê resultados disponíveis na literatura com diferentes stents expansíveis por balão (metal não-recoberto, revestimento passivo, eluição de fármacos), auto-expansíveis e absorvíveis disponíveis para o segmento infrapoplíteo e apresenta recomendações para os futuros avanços tecnológicos dos dispositivos.Palavras-chave: Stents, isquemia, arteriosclerose.

Recanalization of infrapopliteal occlusions

“…Widespread use of stenting is not practiced in the crural vessels, which are of narrow caliber with relatively slow flow that may induce thrombosis. Intimal hyperplasia is another concern [33]. Primary stenting is not recommended [102].…”

“…They are highly flexible to resist fracture and subsequent occlusion, whilst limiting lumen loss as much as p ossible [33].…”

“…Patients with renal failure, or initial occlusions, had worse outcomes. The place of dual antiplatelet therapy with aspirin and clopidogrel to limit this late occlusion is also not clear [33]. Despite the high risk of restenosis and loss of patency after stenting, limb salvage may still be excellent [49].…”

In-situ investigation of stress conditions during expansion of bare metal stents and PLLA-coated stents using the XRD sin2ψ-technique

“…Therefore, non-coronary stents with a strut thickness of some 100 mm were used to show the feasibility of the method. Examples of peripheral vascular applications are iliac (Dyet et al, 2000), infrapopliteal (Bosiers et al, 2008) and renal (Newman-Sanders and Gedroyc, 1995), as well as nonvascular vertebroplasty applications (Fürderer et al, 2002;Rotter et al, 2010). XRD-measurements rely on crystalline materials, such as metals, but can also be used for semi-crystalline materials, such as certain polymers.…”

Treatment of critical lower limb ischemia using a hybrid technique

“…However, the subset of good candidates for the procedure is considerably restricted by prohibitive comorbidities, local skin conditions, absence of suitable vessels for grafting, patient body type (obesity) and inadequate distal bed for revascularization. 3 It is becoming ever more common to treat patients with thoracoabdominal aortic aneurysms using a hybrid technique. In other words, the conventional surgical technique and the endovascular techniques are used in combination, with revascularization of visceral branches originating from the aneurysm and placement of an endoprosthesis.…”