Evaluation of a Polymeric Flap Valve-Attached Ureteral Stent for Preventing Vesicoureteral Reflux in Elevated Intravesical Pressure Conditions: A Pilot Study Using a Porcine Model

Kim, Hyeon Woo; Park, Chang-Ju; Seo, Seungwan; Park, Yangkyu; Lee, Jeong Zoo; Shin, Dong Gil; Moon, Hong Sang; Lee, Jong‐Hyun

doi:10.1089/end.2015.0711

Cited by 13 publications

(8 citation statements)

References 21 publications

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“…In this setting, experimental data would help to test the function (particularly, resistance to retrograde pressure) and durability of the antireflux valve, potentially providing insights into further modifications. Animal models have been utilized to evaluate not only feasibility of drug‐eluting biliary SEMSs 72,73 and biodegradable biliary stents, 74,75 but also antireflux properties of ureteral stents 76–78 . However, there has been a lack of data on ARMSs from animal and phantom studies due to the limited access to those experimental systems.…”

Section: In Vitro Models For Preclinical Evaluation Of Antireflux Valvesmentioning

confidence: 99%

“…Animal models have been utilized to evaluate not only feasibility of drug-eluting biliary SEMSs 72,73 and biodegradable biliary stents, 74,75 but also antireflux properties of ureteral stents. [76][77][78] However, there has been a lack of data on ARMSs from animal and phantom studies due to the limited access to those experimental systems. The in vitro model utilized to evaluate antegrade and retrograde flows in ARMSs consisted of a stent holder, flow controllers, and manometers.…”

Section: Antireflux Metal Stents: Evidence From Clinical Studiesmentioning

confidence: 99%

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Antireflux metal stent for biliary obstruction: Any benefits?

Hamada

Nakai

Isayama

et al. 2020

Digestive Endoscopy

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Endoscopic retrograde cholangiopancreatography with stent placement has been utilized as standard palliative management of distal malignant biliary obstruction (MBO). Compared to plastic stents, metal stents can provide longer‐term relief of symptoms. When a large‐bore metal stent is placed across the ampulla, patients are predisposed to the risk of cholangitis or stent dysfunction due to reflux of duodenal contents. To mitigate the risk of adverse events associated with the duodenobiliary reflux, efforts have been directed to development of antireflux metal stents (ARMSs). The antireflux property has been introduced through adding of an antireflux valve to the duodenal stent end. Evidence from clinical studies indicates that ARMSs may not only reduce the risk of ascending cholangitis during follow‐up but also prolong stent patency time. However, the results of clinical studies testing ARMSs are inconsistent owing to heterogeneous designs of antireflux valves and stent bodies. Metal stents are increasingly indicated for benign biliary strictures and MBO in the setting of neoadjuvant chemotherapy, and therefore, research is warranted to evaluate ARMSs for those indications. Given that endoscopic ultrasound (EUS)‐guided transmural biliary drainage has gained popularity, the optimal timing of placing an ARMS in relation to EUS‐guided and percutaneous drainage should be investigated. Development and evaluation of ARMSs require an integrative approach utilizing phantom and animal models, measurements of stent mechanical properties, and in vivo functional study after stent placement. In this review article, we summarize updated evidence on ARMSs for MBO and discuss issues that should be addressed in future studies.

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Section: In Vitro Models For Preclinical Evaluation Of Antireflux Valvesmentioning

confidence: 99%

Section: Antireflux Metal Stents: Evidence From Clinical Studiesmentioning

confidence: 99%

Antireflux metal stent for biliary obstruction: Any benefits?

Hamada

Nakai

Isayama

et al. 2020

Digestive Endoscopy

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“…The majority of ureter stent studies used pigs as models. These studies tested different surgical procedures and types of ureteral stents [ 44 , 45 , 46 , 47 ]. Rabbits [ 48 , 49 ] and canines [ 32 ] have been used for pyeloplasty and inflammation within urinary tract reconstruction.…”

Section: Discussionmentioning

confidence: 99%

Biodegradable Stent with mTOR Inhibitor-Eluting Reduces Progression of Ureteral Stricture

Su²,

Chang

et al. 2021

IJMS

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In this study, we investigated the effect of mTOR inhibitor (mTORi) drug-eluting biodegradable stent (DE stent), a putative restenosis-inhibiting device for coronary artery, on thermal-injury-related ureteral stricture in rabbits. In vitro evaluation confirmed the dose-dependent effect of mTORi, i.e., rapamycin, on fibrotic markers in ureteral component cell lines. Upper ureteral fibrosis was induced by ureteral thermal injury in open surgery, which was followed by insertion of biodegradable stents, with or without rapamycin drug-eluting. Immunohistochemistry and Western blotting were performed 4 weeks after the operation to determine gross anatomy changes, collagen deposition, expression of epithelial–mesenchymal transition markers, including Smad, α-SMA, and SNAI 1. Ureteral thermal injury resulted in severe ipsilateral hydronephrosis. The levels of type III collagen, Smad, α-SMA, and SNAI 1 were increased 28 days after ureteral thermal injury. Treatment with mTORi-eluting biodegradable stents significantly attenuated thermal injury-induced urinary tract obstruction and reduced the level of fibrosis proteins, i.e., type III collagen. TGF-β and EMT signaling pathway markers, Smad and SNAI 1, were significantly modified in DE stent-treated thermal-injury-related ureteral stricture rabbits. These results suggested that intra-ureteral administration of rapamycin by DE stent provides modification of fibrosis signaling pathway, and inhibiting mTOR may result in fibrotic process change.

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“…To prevent this phenomenon from occurring, several stents with an antireflux mechanism have been designed. At the distal end of the stent, they consist of a valve mechanism that allows drainage of the kidney but closes with increasing intravesical pressure [94] , [95] , [96] .…”

Section: Developments In Improving Stent Characteristicsmentioning

confidence: 99%

“… [94] reached a significantly lower complication rate and higher acceptance rate with an antirefluxive stent. Kim and colleagues [95] developed a flexible polymeric flap valve that can be attached to the intravesical portion of a ureteral stent for the prevention of VUR. This flap valve closes off when intravesical pressure rises above 20 cmH 2 O.…”

Section: Developments In Improving Stent Characteristicsmentioning

confidence: 99%

Ureteral stents in urolithiasis

Beysens

Tailly

2018

Asian Journal of Urology

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Ever since the ureteral stent design was fitted with a curl on both sides to prevent it from migrating up or down the ureter some 40 years ago, its use has gained tremendous momentum, aiding in the rise and evolution of endourology and has confidently kept its place in modern time urology. Over the past four decades, several designs, coating and biomaterials have been developed, trying to reduce infection, encrustation and other stent related symptoms. As the ideal stent has not yet been discovered, different ways of helping patients with their complaints have been researched. This review will cover these aspects of stent use in urolithiasis.

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Evaluation of a Polymeric Flap Valve-Attached Ureteral Stent for Preventing Vesicoureteral Reflux in Elevated Intravesical Pressure Conditions: A Pilot Study Using a Porcine Model

Abstract: A flap valve-attached ureteral stent effectively prevented VUR under conditions of elevated intravesical pressure without urinary obstruction.

Cited by 13 publications

References 21 publications

Antireflux metal stent for biliary obstruction: Any benefits?

Antireflux metal stent for biliary obstruction: Any benefits?

Biodegradable Stent with mTOR Inhibitor-Eluting Reduces Progression of Ureteral Stricture

Ureteral stents in urolithiasis

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