Analysis of trends and prospects regarding stents for human blood vessels

이정희,Eung Do Kim,Eun Jung Jun,유형선,이준우 한국생체재료학회 2018 생체재료학회지 Vol.22 No.1

Background: The purpose of this paper is to provide technology trends and information regarding market and prospects in stents used for human blood vessels in Korea and the world. A stent is a medical device in the form of a cylindrical metal net used to normalize flow when blood or other bodily fluids such as biliary fluids are obstructed in blood vessels, gastrointestinal tracts, etc. by inserting the stent into a narrowed or clogged area. Stents are classified into vascular and non-vascular stents. The coronary artery stent is avascular stent that is used for coronary atherosclerosis. The demand is increasing for stents to treat diseases such as those affecting the heart and blood vessels of elderly and middle-aged patients. Due to the current shift in the demographic structure caused by an aging society, the prospect for stents seems to be very bright. The use of a stent designed to prevent acute vascular occlusion and restenosis, which is a side effect of conventional balloon angioplasty, has rapidly become popular because it can prevent acute complications and improve clinical outcomes. Since the initial release of this stent, there have been significant developments in its design, the most notable of which has been the introduction of drug-eluting stents (DES). Bioresorbable scaffolds (BRS) have the potential to introduce a paradigm shift in interventional cardiology, a true anatomical and functional “vascular restoration” instead of an artificial stiff tube encased by a persistent metallic foreign body. Methods: Data for this research were gathered from primary and secondary sources as well as the databases of the Korea Institute of Science Technology Information (KISTI) located in Seoul, Korea like KISTI Market Report. The sources used for primary research included the databases available from the Korea Institute of Science Technology Information, past industry research services/studies, economic and demographic data, and trade and industry journals. Secondary research was used to supplement and complement the primary research. Interviews were conducted with physicians and surgeons from the key hospitals and senior sale/marketing managers from stent product suppliers in South Korea. Results: The global stent market is estimated at US $ 7.98 billion in 2016 and is expected to grow at a Compound Annual Growth Rate (CAGR) of 3.8% over the next 5 years. As of 2016, the global market for vascular stents is estimated at $ 7.22 billion, with coronary artery stents accounting for 67.3% of the vascular stent market. Among the coronary artery stents, BRS is notably expected to grow at an annual average rate of 8.8% by 2020, but the global adoption rate of BRS remains low at present. In the Korean market, stents for blood vessels account for most of the market, and the market size of stents for blood vessels in Korea was estimated to be 145 billion won as of 2016. Conclusions: In comparison to the sales growth rate of other medical devices, the future stent technology market is judged to be higher in growth potential.

Biodegradable-polymer drug-eluting stents vs. bare metal stents vs. durable-polymer drug-eluting stents: a systematic review and Bayesian approach network meta-analysis

Kang, Si-Hyuck,Park, Kyung Woo,Kang, Do-Yoon,Lim, Woo-Hyun,Park, Kyung Taek,Han, Jung-Kyu,Kang, Hyun-Jae,Koo, Bon-Kwon,Oh, Byung-Hee,Park, Young-Bae,Kandzari, David E.,Cohen, David J.,Hwang, Seung-Sik The European Society of Cardiology 2014 European heart journal Vol.35 No.17

<P><B>Background</B></P><P>The aim of this study was to compare the safety and efficacy of biodegradable-polymer (BP) drug-eluting stents (DES), bare metal stents (BMS), and durable-polymer DES in patients undergoing coronary revascularization, we performed a systematic review and network meta-analysis using a Bayesian framework.</P><P><B>Methods and results</B></P><P>Study stents included BMS, paclitaxel-eluting (PES), sirolimus-eluting (SES), endeavor zotarolimus-eluting (ZES-E), cobalt–chromium everolimus-eluting (CoCr-EES), platinium–chromium everolimus-eluting (PtCr-EES), resolute zotarolimus-eluting (ZES-R), and BP biolimus-eluting stents (BP-BES). After a systematic electronic search, 113 trials with 90 584 patients were selected. The principal endpoint was definite or probable stent thrombosis (ST) defined according to the Academic Research Consortium within 1 year.</P><P><B>Results</B></P><P>Biodegradable polymer-biolimus-eluting stents [OR, 0.56; 95% credible interval (CrI), 0.33–0.90], SES (OR, 0.53; 95% CrI, 0.38–0.73), CoCr-EES (OR, 0.34; 95% CrI, 0.23–0.52), and PtCr-EES (OR, 0.31; 95% CrI, 0.10–0.90) were all superior to BMS in terms of definite or probable ST within 1 year. Cobalt–chromium everolimus-eluting stents demonstrated the lowest risk of ST of all stents at all times after stent implantation. Biodegradable polymer-biolimus-eluting stents was associated with a higher risk of definite or probable ST than CoCr-EES (OR, 1.72; 95% CrI, 1.04–2.98). All DES reduced the need for repeat revascularization, and all but PES reduced the risk of myocardial infarction compared with BMS.</P><P><B>Conclusions</B></P><P>All DESs but PES and ZES-E were superior to BMS in terms of ST within 1 year. Cobalt–chromium everolimus-eluting stents was safer than any DES even including BP-BES. Our results suggest that not only the biodegradability of polymer, but the optimal combination of stent alloy, design, strut thickness, polymer, and drug all combined determine the safety of DES.</P>

Palliative Care of Malignant Ureteral Obstruction with Polytetrafluoroethylene Membrane-Covered Self-Expandable Metallic Stents: Initial Experience

김재한,송강현,조문기,박종욱 대한비뇨의학회 2012 Investigative and Clinical Urology Vol.53 No.9

Purpose: We assessed the efficacy and safety of insertion of a polytetrafluoroethylene membrane-covered self-expandable metallic stent (UVENTA stent) for palliation of malignant ureteral obstruction on the basis of our early results. Materials and Methods: Eighteen patients underwent UVENTA stent insertion for extrinsic malignant ureteral obstructions of 20 ureters. The UVENTA stents were deployed retrogradely under cystoscopy and fluoroscopy. Candidates for the procedure had preexisting double-J stents that were nonfunctional or caused excessive bladder irritation. We recorded the success and patency rate in addition to any complications associated with the procedure. Results: The mean length of obstruction was 10.6 cm (range, 2 to 20 cm). Two ureters were obstructed in the upper ureter, 9 in the lower ureter, and 9 in multiple levels of ureter. Simultaneous balloon dilation was performed in 12 ureters. UVENTA stents were successfully inserted in all patients. No obstruction of the UVENTA stents occurred during the mean follow-up period of 7.3 months (patency rate 100%), but de novo ureteral obstruction developed in 4 ureters. There were no instances of stone formation, hyperplastic reaction, encrustation, or migration. Abnormally elevated serum creatinine decreased to normal levels and hydronephrosis gradually resolved during the 4 weeks after UVENTA insertion. No significant complications developed except for transient and self-limiting hematuria and mild lower abdominal pain. Conclusions: UVENTA stents may relieve malignant ureteral obstruction safely and easily. Long-term follow-up is necessary to assess the role of this stent in the treatment of malignant ureteral obstruction. Purpose: We assessed the efficacy and safety of insertion of a polytetrafluoroethylene membrane-covered self-expandable metallic stent (UVENTA stent) for palliation of malignant ureteral obstruction on the basis of our early results. Materials and Methods: Eighteen patients underwent UVENTA stent insertion for extrinsic malignant ureteral obstructions of 20 ureters. The UVENTA stents were deployed retrogradely under cystoscopy and fluoroscopy. Candidates for the procedure had preexisting double-J stents that were nonfunctional or caused excessive bladder irritation. We recorded the success and patency rate in addition to any complications associated with the procedure. Results: The mean length of obstruction was 10.6 cm (range, 2 to 20 cm). Two ureters were obstructed in the upper ureter, 9 in the lower ureter, and 9 in multiple levels of ureter. Simultaneous balloon dilation was performed in 12 ureters. UVENTA stents were successfully inserted in all patients. No obstruction of the UVENTA stents occurred during the mean follow-up period of 7.3 months (patency rate 100%), but de novo ureteral obstruction developed in 4 ureters. There were no instances of stone formation, hyperplastic reaction, encrustation, or migration. Abnormally elevated serum creatinine decreased to normal levels and hydronephrosis gradually resolved during the 4 weeks after UVENTA insertion. No significant complications developed except for transient and self-limiting hematuria and mild lower abdominal pain. Conclusions: UVENTA stents may relieve malignant ureteral obstruction safely and easily. Long-term follow-up is necessary to assess the role of this stent in the treatment of malignant ureteral obstruction.

ORiginal Article : Preoperative Colonoscopy for Detection of Synchronous Neoplasms after Insertion of Self-Expandable Metal Stents in Occlusive Colorectal Cancer; Comparison of Covered and Uncovered Stents

( Sun Gyo Lim ),( Kwang Jae Lee ),( Kwang Wook Suh ),( Seung Yeop Oh ),( Soon Sun Kim ),( Jun Hwan Yoo ),( Jeong Ook Wi ) The Editorial Office of Gut and Liver 2013 Gut and Liver Vol.7 No.3

Background/Aims: In patients with occlusive colorectal cancers, a complete preoperative evaluation of the colon proximal to the obstruction is often impossible. We aimed to evaluate the feasibility of preoperative colonoscopy after stent placement and to determine whether the success rate of colonoscopy differs between covered and uncovered stents. Methods: Seventy-three patients with malignant colorectal obstruction were enrolled prospectively. In patients with a resectable cancer, a preoperative colonoscopy was performed after insertion of a self-expandable metal stent (SEMS). The success rate of complete preoperative colonoscopy was compared between covered and uncovered stents. Results: Forty-five of 73 patients who underwent stent placement had a resectable cancer (61.6%). A complete preoperative colonoscopy was possible in 40 of 45 patients (88.9%). The success rate of complete preoperative colonoscopy was significantly lower in the covered-stent group when the obstructing mass lesion was located in the sigmoid colon (p=0.024). Synchronous cancer was detected in one patient (2.2%). Stent migration was observed in four patients with a covered stent. Conclusions: A preoperative complete colonoscopy after SEMS placement was feasible and safe in most patients with malignant colorectal obstruction. Uncovered stents seem to have more advantages than covered stents in preoperative colonoscopy proximal to the obstruction. (Gut Liver 2013; 7:311-316)

Preliminary Investigation on Efficacy and Safety of Substance P-Coated Stent for Promoting Re-Endothelialization: A Porcine Coronary Artery Restenosis Model

Park Dae Sung,Oh Seok,진유정,Na Mi Hyang,Kim Munki,Kim Jeong Ha,Hyun Dae Young,Cho Kyung Hoon,Hong Young Joon,Kim Ju Han,Ahn Youngkeun,Hermida-Prieto Manuel,Vázquez-Rodríguez José Manuel,Gutiérrez-Chico 한국조직공학과 재생의학회 2024 조직공학과 재생의학 Vol.21 No.1

Background: Current polymer-based drug-eluting stents (DESs) have fundamental issues about inflammation and delayed re-endothelializaton of the vessel wall. Substance-P (SP), which plays an important role in inflammation and endothelial cells, has not yet been applied to coronary stents. Therefore, this study compares poly lactic-co-glycolic acid (PLGA)-based everolimus-eluting stents (PLGA-EESs) versus 2-methacryloyloxyethyl phosphorylcholine (MPC)-based SP-eluting stents (MPC-SPs) in in-vitro and in-vivo models. Methods: The morphology of the stent surface and peptide/drug release kinetics from stents were evaluated. The in-vitro proliferative effect of SP released from MPC-SP is evaluated using human umbilical vein endothelial cell. Finally, the safety and efficacy of the stent are evaluated after inserting it into a pig's coronary artery. Results: Similar to PLGA-EES, MPC-SP had a uniform surface morphology with very thin coating layer thickness (2.074 μm). MPC-SP showed sustained drug release of SP for over 2 weeks. Endothelial cell proliferation was significantly increased in groups treated with SP (n = 3) compared with the control (n = 3) and those with everolimus (n = 3) (SP: 118.9 ± 7.61% vs. everolimus: 64.3 ± 12.37% vs. the control: 100 ± 6.64%, p < 0.05). In the animal study, the percent stenosis was higher in MPC-SP group (n = 7) compared to PLGA-EES group (n = 7) (MPC-SP: 28.6 ± 10.7% vs. PLGA-EES: 16.7 ± 6.3%, p < 0.05). MPC-SP group showed, however, lower inflammation (MPC-SP: 0.3 ± 0.26 vs. PLGA-EES: 1.2 ± 0.48, p < 0.05) and fibrin deposition (MPC-SP: 1.0 ± 0.73 vs. PLGA-EES: 1.5 ± 0.59, p < 0.05) around the stent strut. MPC-SP showed more increased expression of cluster of differentiation 31, suggesting enhanced re-endothelialization. Conclusion: Compared to PLGA-EES, MPC-SP demonstrated more decreased inflammation of the vascular wall and enhanced re-endothelialization and stent coverage. Hence, MPC-SP has the potential therapeutic benefits for the treatment of coronary artery disease by solving limitations of currently available DESs. Background: Current polymer-based drug-eluting stents (DESs) have fundamental issues about inflammation and delayed re-endothelializaton of the vessel wall. Substance-P (SP), which plays an important role in inflammation and endothelial cells, has not yet been applied to coronary stents. Therefore, this study compares poly lactic-co-glycolic acid (PLGA)-based everolimus-eluting stents (PLGA-EESs) versus 2-methacryloyloxyethyl phosphorylcholine (MPC)-based SP-eluting stents (MPC-SPs) in in-vitro and in-vivo models. Methods: The morphology of the stent surface and peptide/drug release kinetics from stents were evaluated. The in-vitro proliferative effect of SP released from MPC-SP is evaluated using human umbilical vein endothelial cell. Finally, the safety and efficacy of the stent are evaluated after inserting it into a pig's coronary artery. Results: Similar to PLGA-EES, MPC-SP had a uniform surface morphology with very thin coating layer thickness (2.074 μm). MPC-SP showed sustained drug release of SP for over 2 weeks. Endothelial cell proliferation was significantly increased in groups treated with SP (n = 3) compared with the control (n = 3) and those with everolimus (n = 3) (SP: 118.9 ± 7.61% vs. everolimus: 64.3 ± 12.37% vs. the control: 100 ± 6.64%, p < 0.05). In the animal study, the percent stenosis was higher in MPC-SP group (n = 7) compared to PLGA-EES group (n = 7) (MPC-SP: 28.6 ± 10.7% vs. PLGA-EES: 16.7 ± 6.3%, p < 0.05). MPC-SP group showed, however, lower inflammation (MPC-SP: 0.3 ± 0.26 vs. PLGA-EES: 1.2 ± 0.48, p < 0.05) and fibrin deposition (MPC-SP: 1.0 ± 0.73 vs. PLGA-EES: 1.5 ± 0.59, p < 0.05) around the stent strut. MPC-SP showed more increased expression of cluster of differentiation 31, suggesting enhanced re-endothelialization. Conclusion: Compared to PLGA-EES, MPC-SP demonstrated more decreased inflammation of the vascular wall and enhanced re-endothelialization and stent coverage. Hence, MPC-SP has the potential therapeutic benefits for the treatment of coronary artery disease by solving limitations of currently available DESs.

16-Slice CT를 이용한 관상 동맥 Stent 재협착의 비침습적 평가

유은혜,최병욱,정남식,서재승,김영진,김태훈,최규옥 대한영상의학회 2007 대한영상의학회지 Vol.56 No.5

Purpose: We strove to evaluate in-stent restenosis of the coronary artery by measuring the in-stent CT attenuation with using 16-multislice CT. Materials and Methods: We analyzed the coronary CT angiography, with using 16-slice CT, in 45 stents of 30 patients. The CT attenuation was measured in the lumen of the stented segments and in the lumen of the segment proximal to the stents, and this attenuation was compared with each other. The CT attenuation difference between them was analyzed in relation to the presence of significant in-stent restenosis. Conventional coronary angiography was used as a standard of reference for in-stent restenosis. Results: 12 stents in 12 patients revealed significant restenosis on the conventional coronary angiography. In 6 (50%) of them, the CT attenuation value of the in-stent lumen was lower than that of the proximal segments (373.8 HU vs. 497.1 HU, respectively, p=0.77). In the other 6 stents, a small stent diameter (n=3) and adjacent severe calcification (n=2) accounted for the higher CT attenuation value of the in-stent lumen. In all the stents without significant restenosis, the CT attenuation values of the in-stent lumens were higher than those of their proximal segments. Conclusion: The measurement of CT attenuation with using 16-slice CT at the in-stent lumen as compared to the attenuation of the proximal segment provides an objective, confident method for the diagnosis of in-stent restenosis. 목적: 16-절편 CT 관동맥조영술에서의 관동맥 스텐트 내강의 감쇠치(attenuation value)를 이용하여 스텐트 재협착을 비침습적으로 평가하고자 하였다. 대상과 방법: 16-slice CT로 coronary CT angiography 시행한 30명 환자의 stents 45개를 분석하였다. Stent 내강과 근위부 정상 관상동맥 분절에서 CT 감쇠치를 서로 비교하여 그 감쇠치차와 stent 재협착 정도간의 연관성을 파악하였다. 이때 고식적 혈관 촬영술을 기준으로 삼고 비교하였다. 결과: 고식적 혈관 촬영술에서 12명 환자의 12개 stents에서 유의한 재협착을 보였고 이들 중 6개에서 stent 내강의 CT 감쇠치가 근위부 동맥의 값보다 더 낮았다. 다른 6개 stents에서는 stent 내강의 감쇠치가 더 높았는데 이들 중 3개 stents는 직경이 작았고, 2개는 석회가 동반되었다. 유의한 재협착이 없었던 stents 모두에서 stent 내강 감쇠치는 근위부 동맥에서보다 더 높았다. 결론: stent 재협착 진단에 있어 16-slice CT에서의 stent 내강과 근위부 관상 동맥의 감쇠치 비교는 객관적인 방법이다. 작은 직경의 stent나 심한 석회화는 이 방법에서 부정확한 결과를 일으키는 주요 원인이다.

하나로 자가팽창 금속 스탠트를 이용한 돼지 경동맥에서의 실험적 연구

서대철 대한영상의학회 1996 대한영상의학회지 Vol.34 No.6

Purpose : To evaluate the patency of the Hanaro self-expanding stainless steel stent in the common carotid artery of the pig. Materials and Methods : Sixteen stents(6mm in diameter/3.5mm in length) were inserted in one or both common carotid arteries of nine pigs. Carotid angiography was performed before and after stent insertion, and at the end of the follow-up period(which ranged from 4 to 13 weeks), to evaluate stent patency and change of stent location. Histopathologic study was carried out to assess the endothelial proliferation. Results : Of nine pigs with 16 successfully-inserted stents, follow-up angiography was obtained in seven pigs with 13 stents. The stents inserted were patent in 12 cases and occluded in one. Stenosis was noted in nine of the 12 stents. In three stents, there was angiographic evidence of recanalization such as non-filling or collateral filling of the rete. In no case was there any change of stent location. Endothelial proliferation was more severe in two of four occluded stents(mean thickness : 0.43mm) than in the other 11 stents(mean thickness : 0.08mm). Conclusion : Because the Hanaro stent was successfully inserted in porcine carotid arteries and showed a rather good patency(92%), the stent can be used in the small arteries. However, before it is used clinically, futher study and development appear to be necessary.

Inner surface modification of polyurethane ureteral stents using plasma-enhanced chemical vapor deposition to improve the resistance to encrustation in a pig model

정재훈,백남욱,임현아,서찬용,조용기,정동근,한덕현 대한비뇨의학회 2023 Investigative and Clinical Urology Vol.64 No.2

Purpose: We developed a ureteral stent with a non-fouling inner surface using plasma micro-surface modification technology. This study aimed to evaluate the safety and efficacy of this stent in animal model. Materials and Methods: Ureteral stents were placed in five Yorkshire pigs. A bare stent was inserted on one side and an inner surface-modified stent was inserted on the other side. Two weeks after stenting, laparotomy was performed to harvest the ureteral stents. The changes in the inner surface were grossly evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). In addition, if encrustation was observed, the components were analyzed using Fourier transform infrared spectroscopy. Urine cultures were used for safety assessment. Results: In all models, urine cultures did not show any bacterial growth before and after stenting, and stent-related complications were not identified. Hard materials were palpable in four bare models. Palpable material was not identified in the modified stent. Calcium oxalate dihydrate/uric acid stones were identified in two bare stents. In the SEM images with EDS, biofilm formation was confirmed in the bare stents. Biofilm formation was significantly less on the inner surface of the modified stent, and the intact surface of the modified stent was larger than that of the bare stent. Conclusions: The application of a specialized, plasma-enhanced, chemical vapor deposition technology to the inner surface of ureteral stents was safe and showed resistance to biofilm formation and encrustation.

Surgical outcomes in dogs with tracheal collapse treated with a novel cross-and-hook braided endoluminal stent

Uemura, Akiko,Ozai, Yusuke,Hamabe, Lina,Yoshida, Tomohiko,Tanaka, Ryou The Korean Society of Veterinary Science 2022 Journal of Veterinary Science Vol. No.

Background: Stenting is an effective treatment option for tracheal collapse in dogs. Cross-braided tracheal stents are currently the norm in veterinary medicine, but cross-and-hook braided stents have recently been adopted in human medicine. We examined whether stents manufactured using this novel braiding technique provided additional advantages for the treatment of tracheal collapse in dogs. Objectives: To evaluate the outcomes of cross-and-hook braided stent implantation in the treatment of tracheal collapse in dogs. Methods: The medical records of 22 client-owned dogs that underwent luminal placement of cross-and-hook braided Fauna Stents for the treatment of tracheal collapse between January 2018 and July 2021 were examined and data on canine signalment, clinical signs, diagnostic test results, surgical outcomes, and postoperative complications were retrieved and analyzed statistically. Results: Twenty-six stents were surgically implanted, with 20 dogs (90.9%) receiving one stent and the remaining two (9.1%) receiving two or more stents. All dogs survived the procedure. The median survival time at a median follow-up of 990 days was 879 days. At the final follow-up examination, loss or mild improvement of cough was observed in all dogs. Conclusions: Compared with conventional lumen stents, the cross-and-hook braided Fauna Stent offered a higher survival rate and improved clinical symptoms in all patients. The results of this study suggest that the Fauna Stent may be a promising treatment option for dogs with tracheal collapse.

Overlapping Stents-Assisted Coiling for Vertebral Artery Dissecting Aneurysm : LVIS Stent within Neuroform EZ Stent

Liu, Xing-Long,Wang, Bin,Zhao, Lin-Bo,Jia, Zhen-Yu,Shi, Hai-Bin,Liu, Sheng The Korean Neurosurgical Society 2022 Journal of Korean neurosurgical society Vol.65 No.4

Objective : To evaluate the safety and efficacy of an overlapped stenting-assisted coiling technique in treating vertebral artery dissecting aneurysm (VADA) via Low-profile Visualized Intraluminal Support (LVIS) stent-within-Neuroform EZ stent. Methods : From January 2017 to June 2019, 18 consecutive patients with VADAs (ruptured : unruptured=5 : 13) were treated with the overlapping stents assisted-coiling technique in our center. The overlapping manner was a Neuroform EZ stent being deployed first, followed by LVIS stents placement using the 'shelf' technique. The patients' clinical characteristics, technical feasibility and safety, and immediate and follow-up angiographic results were retrospectively reviewed. Results : Seventeen (94.4%) procedures were technically successful with an exact deployment of the stents and patent parent or perforator arteries. The immediate angiographies after procedure confirmed Raymond class I, II, and III occlusion of VADAs were in 12 (66.7%), two (11.1%), and four cases (22.2%), respectively. Post-procedural complications developed in one patient (5.6%) with minor brainstem infarctions, which resulted from an in-stent thrombosis during the procedure. Angiographic follow-up at 5.7 months (range 3 to 9 months) demonstrated Raymond class I and II occlusion were in all cases (100%). The modified Rankin Scale scores at 21.3 months (range 15 to 42 months) 0-2 in 17 cases (94.4%) and three in one case (5.6%). Conclusion : Overlapping stents via LVIS stent-within-Neuroform EZ stent combined with coiling is safe and effective for patients with VADA in the midterm results.