自體動靜脈瘻管（arteriovenous fistula, AVF）是血液透析（hemodialysis, HD）患者的首選透析管路，因其具有較長的存活時間和較少的併發症。然而，在AVF手術後可能會因初始靜脈直徑不足，導致血流量不理想，影響AVF成熟化的成功率。另外，AVF手術後患者通常需等待二到三個月的時間讓AVF成熟後才能進行血液透析。研究指出，在手術中使用支架置入的方法能夠擴大靜脈直徑，進而提高血流量，從而提高AVF成功成熟的機會及縮短成熟化所需要的時間。然而，目前市售的靜脈支架大多為金屬材質，一旦置入血管內，支架將永久存於體內，增加了血管再狹窄和血栓形成等風險。因此，金屬支架在臨床上並不常被使用來協助AVF的成熟化。而可降解聚合物支架雖然可以解決金屬支架永久留存於體內的問題，但其機械性質較弱，無法提供協助AVF成熟化所需的血管擴張能力。
因此，本研究提出新的方法，結合氣球重複擴張靜脈和生物可降解聚合物支架，來達成協助及加速AVF成熟化。透過氣球重複擴張靜脈的方式，使靜脈出現鬆弛的現象，並透過置入聚合物支架來擴張鬆弛後的靜脈。由實驗結果得知本研究所提出的方法能有效擴張豬內頸靜脈內徑，由3.91±0.02 mm至6.54±0.07 mm，達成成熟後靜脈瘻管所需直徑。同時，為了保護可能受傷的靜脈並降低出血風險，本研究提出了使用覆膜支架的概念。覆膜的使用可將受傷的靜脈壁與血液流動區域分隔開，減少可能發生的靜脈壁二次損傷，以加速靜脈壁的自我修復。

Autologous arteriovenous fistula (AVF) is the preferred dialysis line for patients with hemodialysis (HD) due to its longer survival time and fewer complications. However, after AVF surgery, the initial venous diameter may be insufficient, resulting in unsatisfactory blood flow and affecting the success rate of AVF maturation. In addition, after AVF surgery, patients usually wait two to three months for the AVF to mature before undergoing hemodialysis. Studies have shown that the use of stenting can increase vein diameter and blood flow, thereby increasing the success rate of AVF maturation and reducing the time required for maturation. However, most of the venous stents currently on the market are made of metal, and once placed in the blood vessel, the stent will remain in the body permanently, increasing the risk of vascular restenosis and thrombosis. Therefore, metal stents are not often used clinically to assist in AVF maturation. While degradable polymer stents can solve the problem of permanent retention of metal stents in the body, their mechanical properties are weak and cannot provide the vasodilation capacity required to assist AVF maturation.
Therefore, this study proposes a novel approach to assist and accelerate AVF maturation in combination with balloon repeated venous dilation and biodegradable polymer stents. The vein was relaxed by repeated dilation of the balloon, and the relaxed vein was dilated by placing a polymer stent. According to the experimental results, the method proposed in this study can effectively expand the internal diameter of the internal jugular vein of pigs from 3.91±0.02 mm to 6.54±0.07 mm, reaching the required diameter of mature venous fistula. At the same time, in order to protect potentially injured veins and reduce the risk of bleeding, the concept of using a covered stent was proposed in this study. The use of stent membrane can separate the injured vein wall from the blood flow, reduce the possible secondary damage to the vein wall, and accelerate the self-repair of the vein wall.

1.衛生福利部中央健康保險署. 國人全民健康保險就醫疾病資訊. 2021; Available from: https://www.nhi.gov.tw/Content_List.aspx?n=D529CAC4D8F8E77B&topn=23C660CAACAA159D.
2.Taiwan, K.D.i. 台灣腎病年報. 2021; Available from: https://www.tsn.org.tw/twrds/20220829/8d02a166-9a9b-4e17-927b-f9970d39ab44/8d02a166-9a9b-4e17-927b-f9970d39ab44.pdf.
3.Murea, M., et al. Vascular access for hemodialysis: A perpetual challenge. in Seminars in dialysis. 2019. Wiley Online Library.
4.康健知識庫. 慢性腎臟病. 2023; Available from: https://kb.commonhealth.com.tw/library/450.html?rec=ch-kb-i2i-1&from_id=health-178&from_index=1&from_area=area01#next-data-12-collapse.
5.Dixon, B., Why don't fistulas mature? Kidney international, 2006. 70(8): p. 1413-1422.
6.He, Y., et al., Analyses of hemodialysis arteriovenous fistula geometric configuration and its associations with maturation and reintervention. Journal of vascular surgery, 2021. 73(5): p. 1778-1786. e1.
7.Fontseré, N., et al., Effect of a postoperative exercise program on arteriovenous fistula maturation: a randomized controlled trial. Hemodialysis International, 2016. 20(2): p. 306-314.
8.Bashar, K., et al., Arteriovenous fistula in dialysis patients: factors implicated in early and late AVF maturation failure. The Surgeon, 2016. 14(5): p. 294-300.
9.Bashar, K., et al., The role of venous diameter in predicting arteriovenous fistula maturation: when not to expect an AVF to mature according to pre-operative vein diameter measurements? A best evidence topic. International Journal of Surgery, 2015. 15: p. 95-99.
10.Dageforde, L.A., et al., Increased minimum vein diameter on preoperative mapping with duplex ultrasound is associated with arteriovenous fistula maturation and secondary patency. Journal of Vascular Surgery, 2015. 61(1): p. 170-176.
11.Quencer, K.B. and M. Arici, Arteriovenous fistulas and their characteristic sites of stenosis. American Journal of Roentgenology, 2015. 205(4): p. 726-734.
12.Bax, B. and J. Müssig, Impact and tensile properties of PLA/Cordenka and PLA/flax composites. Composites Science and Technology, 2008. 68(7-8): p. 1601-1607.
13.Lim, L.-T., R. Auras, and M. Rubino, Processing technologies for poly (lactic acid). Progress in Polymer Science, 2008. 33(8): p. 820-852.
14.Nampoothiri, K.M., N.R. Nair, and R.P. John, An overview of the recent developments in polylactide (PLA) research. Bioresource Technology, 2010. 101(22): p. 8493-8501.
15.Lu, S., et al., Is There Light at the End of the Thin-Strut Tunnel? In Vitro Insights on Strut Thickness Impact on Thrombogenicity in Bioresorbable Stents or Scaffolds. JACC: Cardiovascular Interventions, 2018. 11(7): p. 714-716.
16.Bylsma, L., et al., Arteriovenous fistulae for haemodialysis: a systematic review and meta-analysis of efficacy and safety outcomes. European Journal of Vascular and Endovascular Surgery, 2017. 54(4): p. 513-522.
17.Hossny, A., Brachiobasilic arteriovenous fistula: different surgical techniques and their effects on fistula patency and dialysis-related complications. Journal of Vascular Surgery, 2003. 37(4): p. 821-826.
18.(CVSKL), C.V.S.K.L., Arteriovenous Fistula (AVF). 2020.
19.Konner, K., B. Nonnast-Daniel, and E. Ritz, The Arteriovenous Fistula. Journal of the American Society of Nephrology, 2003. 14(6): p. 1669-1680.
20.臨床工学技士の熱血透析blog, 自己血管内シャント（AVF）を解説《吻合方法3つ・作成部位・タバチエールシャント・シャント手術など》. 2021. Available from：https://iryou-kenkou-morichan.com/avf/
21.Manne, V., et al., Can pre and postoperative vein diameter and postoperative flow velocities influence the patency of vascular access in hemodialysis patients? Indian Journal of Vascular and Endovascular Surgery, 2018. 5(3): p. 145-148.
22.Barton, M., et al., Balloon angioplasty–the legacy of Andreas Grüntzig, MD (1939–1985). Frontiers in Cardiovascular Medicine, 2014. 1: p. 15.
23.Im, S.H., et al., Current status and future direction of metallic and polymeric materials for advanced vascular stents. Progress in Materials Science, 2022. 126: p. 100922.
24.Luckachan, G.E. and C. Pillai, Biodegradable polymers-a review on recent trends and emerging perspectives. Journal of Polymers and the Environment, 2011. 19: p. 637-676.
25.Toong, D.W.Y., et al., Bioresorbable metals in cardiovascular stents: Material insights and progress. Materialia, 2020. 12: p. 100727.
26.McMahon, S., et al., Bio-resorbable polymer stents: a review of material progress and prospects. Progress in Polymer Science, 2018. 83: p. 79-96.
27.Pauck, R. and B. Reddy, Computational analysis of the radial mechanical performance of PLLA coronary artery stents. Medical Engineering & Physics, 2015. 37(1): p. 7-12.
28.Hu, T., et al., Biodegradable stents for coronary artery disease treatment: Recent advances and future perspectives. Materials Science and Engineering: C, 2018. 91: p. 163-178.
29.Wang, X.-L., K.-K. Yang, and Y.-Z. Wang, Properties of starch blends with biodegradable polymers. Journal of Macromolecular Science, Part C: Polymer Reviews, 2003. 43(3): p. 385-409.
30.Folino, A., et al., Biodegradation of wasted bioplastics in natural and industrial environments: A review. Sustainability, 2020. 12(15): p. 6030.
31.Letcher, T. and M. Waytashek. Material property testing of 3D-printed specimen in PLA on an entry-level 3D printer. in ASME international mechanical engineering congress and exposition. 2014. American Society of Mechanical Engineers.
32.Grasso, M., et al., Effect of temperature on the mechanical properties of 3D-printed PLA tensile specimens. Rapid Prototyping Journal, 2018. 24(8): p. 1337-1346.
33.Tiwari, N., et al., Morphology of dorsal venous arch of hand: a cadaveric study. Journal of College of Medical Sciences-Nepal, 2019. 15(2): p. 139-143.
34.嘉應學院醫學院解剖教研室，豬新解剖（Dissection of pig heart）. 2016. Available from：http://www.jyxyyxyjpjys.com/nd.jsp?id=227
35.Khalaj, R., et al., 3D printing advances in the development of stents. International Journal of Pharmaceutics, 2021. 609: p. 121153.
36.Guerra, A., A. Roca, and J. de Ciurana, A novel 3D additive manufacturing machine to biodegradable stents. Procedia Manufacturing, 2017. 13: p. 718-723.
37.Chang, F.-Y., et al., Using 3D printing and femtosecond laser micromachining to fabricate biodegradable peripheral vascular stents with high structural uniformity and dimensional precision. The International Journal of Advanced Manufacturing Technology, 2021. 116: p. 1523-1536.
38.MODEX, PLA. Available from：https://www.modex3d.com/product/154
39.張耀邦, 新型主動脈瘤支架設計及製作並以仿真主動脈瘤血管模型進行功能驗證, in 機械工程系. 2021, 國立臺灣科技大學: 台北市. p. 136.
40.Zhao, D., et al., Experimental study of polymeric stent fabrication using homemade 3D printing system. Polymer Engineering & Science, 2019. 59(6): p. 1122-1131.
41.Douglas, C.M., Design and analysis of experiments. John Wiley and Sons, 2001.
42.Westerhof, N., et al., Elasticity. Snapshots of Hemodynamics: An Aid for Clinical Research and Graduate Education, 2019: p. 57-64.
43.Brandt-Wunderlich, C., et al., Support function of self-expanding nitinol stents–Are radial resistive force and crush resistance comparable? Current Directions in Biomedical Engineering, 2019. 5(1): p. 465-467.