Effects of percutaneous endovascular angioplasty for severe stenosis or occlusion of subclavian artery.

To investigate the effect and safety of percutaneous endovascular angioplasty (PEA) with optional stenting for the treatment of severe stenosis or occlusion of subclavian artery, patients with severe stenosis ≥ 70% or occlusion of subclavian artery treated with PEA were retrospectively enrolled. The clinical data were analyzed. A total of 222 patients were retrospectively enrolled, including 151 males (68.0%) and 71 females (32.0%) aged 48-86 (mean 63.9 ± 9.0) years. Forty-seven (21.2%) patients had comorbidities. Subclavian artery stenosis ≥ 70% was present in 201 (90.5%) patients and complete subclavian occlusion in 21 (9.5%) cases. Angioplasty was successfully performed in all (100%) patients. Balloon-expandable stents were used in 190 (85.6%) cases, and self-expandable stents in 20 (9.0%) cases. Only 12 (5.4%) cases were treated with balloon dilation only. Among 210 patients treated with stent angioplasty, 71 (33.8% or 71/210) cases underwent balloon pre-dilation, 139 (66.2% or 139/210) had direct deployment of balloon-expandable stents, and 2 (1.0% or 2/210) experienced balloon post-dilation. Distal embolization protection devices were used in 5 (2.3% or 5/222) cases. Periprocedural complications occurred in 3 (1.4%) patients, including aortic dissection in 2 (0.9%) cases and right middle cerebral artery embolism in 1 (0.5%). No hemorrhage occurred. Among 182 (82.0%) patients with 6-month follow-up, restenosis > 70% occurred in 1 (0.5%) patient, and among 68 (30.6%) patients with 12-month follow-up, restenosis > 70% took place in 11 (16.2%) patients. Percutaneous endovascular angioplasty can be safely and efficiently performed for the treatment of severe stenosis ≥ 70% or occlusion of subclavian artery.

[Three-dimensional printed 316L stainless steel cardiovascular stent's electrolytic polishing and its mechanical properties].

The interventional therapy of vascular stent implantation is a popular treatment method for cardiovascular stenosis and blockage. However, traditional stent manufacturing methods such as laser cutting are complex and cannot easily manufacture complex structures such as bifurcated stents, while three-dimensional (3D) printing technology provides a new method for manufacturing stents with complex structure and personalized designs. In this paper, a cardiovascular stent was designed, and printed using selective laser melting technology and 316L stainless steel powder of 0-10 µm size. Electrolytic polishing was performed to improve the surface quality of the printed vascular stent, and the expansion behavior of the polished stent was assessed by balloon inflation. The results showed that the newly designed cardiovascular stent could be manufactured by 3D printing technology. Electrolytic polishing removed the attached powder and reduced the surface roughness Ra from 1.36 µm to 0.82 µm. The axial shortening rate of the polished bracket was 4.23% when the outside diameter was expanded from 2.42 mm to 3.63 mm under the pressure of the balloon, and the radial rebound rate was 2.48% after unloading. The radial force of polished stent was 8.32 N. The 3D printed vascular stent can remove the surface powder through electrolytic polishing to improve the surface quality, and show good dilatation performance and radial support performance, which provides a reference for the practical application of 3D printed vascular stent.

Three-dimensional printed 316L stainless steel cardiovascular stent's electrolytic polishing and its mechanical properties / 生物医学工程学杂志

The interventional therapy of vascular stent implantation is a popular treatment method for cardiovascular stenosis and blockage. However, traditional stent manufacturing methods such as laser cutting are complex and cannot easily manufacture complex structures such as bifurcated stents, while three-dimensional (3D) printing technology provides a new method for manufacturing stents with complex structure and personalized designs. In this paper, a cardiovascular stent was designed, and printed using selective laser melting technology and 316L stainless steel powder of 0-10 µm size. Electrolytic polishing was performed to improve the surface quality of the printed vascular stent, and the expansion behavior of the polished stent was assessed by balloon inflation. The results showed that the newly designed cardiovascular stent could be manufactured by 3D printing technology. Electrolytic polishing removed the attached powder and reduced the surface roughness Ra from 1.36 µm to 0.82 µm. The axial shortening rate of the polished bracket was 4.23% when the outside diameter was expanded from 2.42 mm to 3.63 mm under the pressure of the balloon, and the radial rebound rate was 2.48% after unloading. The radial force of polished stent was 8.32 N. The 3D printed vascular stent can remove the surface powder through electrolytic polishing to improve the surface quality, and show good dilatation performance and radial support performance, which provides a reference for the practical application of 3D printed vascular stent.

The Relationship between Perivertebral Venous Cement Embolism and Balloon Expansion Pressure in Balloon Kyphoplasty.

INTRODUCTION: Osteoporotic vertebral compression fractures (OVCFs) are common fractures in the elderly suffering osteoporosis. Most patients have bone fusion with deformity of vertebral collapse; however, some patients suffer nonunion and persistent pain at the fracture site. Due to the limitations of conservative treatment, balloon kyphoplasty (BKP) has been recently performed for OVCFs. This study aimed to investigate the relationship between cement embolization and balloon expansion pressure (BEP) in patients who underwent BKP. METHODS: We investigated 62 patients who underwent BKP for cement embolization into the perivertebral veins among the 155 patients admitted to our hospital due to thoracolumbar vertebral compression fractures between April 1, 2019, and March 31, 2020. Surgery was indicated for patients who had severe back or low back pain and whose daily life was severely impaired, and in whom the shape of the vertebral body was clearly changed on functional X-ray. RESULTS: Intraoperative X-ray and postoperative CT revealed cement embolization into the perivertebral veins in three cases (4.83%). The BEP was significantly higher in the group with cement embolism than in the group without cement embolism (P < 0.001). Pulmonary cement embolism (PCE) and infection were not observed. One case of cement leakage into the spinal canal was observed (1.61%). CONCLUSIONS: While the surgical intervention of BKP can contribute to the treatment of OVCFs, careful attention should be paid to the prevention of complications, including cement embolization into the perivertebral veins, and such complications should be appropriately managed.

Silk Fibroin as a Coating Polymer for Sirolimus-Eluting Magnesium Alloy Stents.

Magnesium (Mg) alloy-based, bioresorbable scaffolding is a promising candidate for next-generation stents. Rapid corrosion of Mg alloy in the physiological environment, however, hinders its clinical application. Hydrofluoric acid (HF) treatment and biodegradable polymer coating have been widely reported to enhance corrosion resistance of the Mg alloy. Poor biocompatibility of biodegradable polymers, however, is known to promote adverse events such as intimal hyperplasia and thrombosis. We selected silk fibroin (SF) as the polymer for stent coating and evaluated drug release from the SF layer, corrosion resistance of the Mg alloy, and biocompatibility. After the stent was coated with SF, ethanol treatment of the SF layer enriched the ß-sheet content. Release of sirolimus (SRL), a drug that prevents intimal hyperplasia, from the SF layer was slower than that with a poly(ε-caprolactone), the conventional biodegradable polymer used on medical devices. Ethanol treatment of the SF-coated stent further slowed SRL release from the SF layer. Crystalline domains in SF formed by the ß-sheet structure could contribute to the slow release of SRL. The SF coating suppressed local and deep corrosion of the Mg alloy stent, although total corrosion remained unaffected. Uniform corrosion without local or deep corrosion prolongs the stent's radial strength. The SF coating showed excellent biocompatibility with human umbilical vein endothelial cells and minimal platelet adhesion. SF is expected to replace traditional biodegradable polymers for use on bioresorbable stents.

Interventional therapy for biliary restenosis occurring after surgical T-tube drainage: preliminary investigation / 介入放射学杂志

Objective To evaluate the curative effect,safety and feasibility of interventional therapy for biliary restenosis occurring after surgical T-tube drainage.Methods The clinical data of 25 patients with biliary restenosis that occurred after surgical T-tube drainage,who were admitted to authors' hospital during the period from June 2014 to March 2016,were retrospectively analyzed.The primary diseases included bile duct carcinoma (n=6),gallbladder carcinoma (n=3),biliary stone (n=13),hepatocellular carcinoma (n=2)and gastric cancer after surgery (n=1).Abnormal junction of pancreatic duct and biliary duct was observed in 4 patients.Interventional procedure via T-tube route was carried out in 22 patients,and T-tube radiography with subsequent percutaneous transhepatic cholangial drainage (PTCD) was conducted in 3 patients.Biliary balloon expansion combined with biliary drainage was performed in 21 patients,and biliary metal stent implantation was adopted in 4 patients.For patients with benign biliary stricture,the drainage tube was retained for 2-3 months before it was removed.All the patients were followed up for 3-24 months at outpatient clinic or by the telephone.The curative effect was evaluated with drainage-tube radiography.Results The interventional operation was successfully accomplished in all patients,no procedure-related complications occurred,the technical success rate was 100％.In 15 patients with benign biliary stricture,biliary plasty with balloon expansion via the T-tube fistula was conducted,then a 10.2-12 F drainage catheter was placed in the biliary tract and the T-tube was pulled out.During the follow-up period,one patient with anastomotic stricture of bile duct carcinoma died of pulmonary infection at 8 months after treatment.Of the 10 patients with malignant stricture,the biliary obstruction was located above the T-tube level in 3,and all the 3 patients received PTCD.Among the 3 patients,2 patients had hepatocellular carcinoma complicated by biliary invasion,as the extent of the cancerous thrombus was very large,both internal drainage tube and external drainage tube had to be implanted.After jaundice regression,the two patients died of hepatic failure at one month and 2.2 months after the operation respectively.One patient with gallbladder carcinoma complicated by invasion of bile duct received implantation of biliary stent,and the patient died of tumor deterioration at 2.5 months after the procedure.In 7 patients,the biliary obstruction was located below the T-tube level.hnplantation of internal drainage tube and external drainage tube via the Ttube fistula was performed in 4 patients,and implantation of metal stent was adopted in 3 patients.Among them,2 patients with gallbladder carcinoma died of tumor deterioration at 3.8 months and 5 months after the operation respectively.In 5 patients with cholangiocarcinoma,biliary stent restenosis occurred in 2 at 3 months after the treatment,and PTCD was adopted.Three patients died of tumor deterioration complicated by organ function failure at 3.6 months,5.2 months and 9.0 months after the operation respectively.Conclusion For the treatment of biliary restenosis occurring after surgical T-tube drainage,interventional therapy is safe and feasible with reliable curative effect,it can significantly improve the life quality of patients.

Clinical effect of drug-eluting stents implantation and balloon expansion in treatment of patients with knee artery lesions / 中国综合临床

Objective To compare the clinical effect of drug-eluting stents implantation or pure balloon expansion for the treatment of patients with knee artery lesions. Methods Sixty-eight patients with knee artery lesions were randomly and voluntarily divided into the control group( n=34 )and observation group( n=34 ) . The patients in the control group were given balloon expansion treatment,while in observation group were implanted drug-eluting stents besides balloon expansion. Pathological changes of skin temperature,percutaneous oxygen partial pressure( TcPO2 ),ankle brachial index( ABI),and the recurrence rate of patients before and after treatment for 6 months and 12 months were recorded and compared. Results After 6 months treatment,TcPO2 and ABI in observation group were(35. 4 ± 4. 5)mmHg and 0. 85 ± 0. 04,significantly higher than that in control group(( 28. 2 ± 3. 5 ) mmHg and 0. 62 ± 0. 03 ),and the differences were statistically significant( t=2. 535,2. 185;P﹤0. 05). At 12 months after treatment,skin temperature,TcPO2,ABI in observation group were(32. 4 ± 4. 3)℃,(34. 3 ± 4. 2)mmHg and 0. 80 ± 0. 04,significantly higher than that of the control group ((28. 6 ± 3. 7)℃,(26. 4 ± 3. 6)mmHg,0. 53 ± 0. 02;t =2. 354,2. 648,2. 064;P ﹤0. 05). Meanwhile,the recurrence rate was 5. 9% in observation group,significantly lower than that of the control group( 32. 4%;χ2=8. 463,P﹤0. 05). Conclusion The clinical effect of drug-eluting stents implantation in treatment of patients with knee artery lesions is superior to that of balloon expansion.

Finite element methods to analyze helical stent expansion.

Helical polymeric stents have been proposed as a suitable geometry for biodegradable drug-eluting polymer-based stents. However, helical stents often experience nonuniform local expansion (dog boning), which can prohibit full stent expansion using conventional methods. The development of stents and deployment methods is challenging and can be supported by numerical analysis; however, this complex problem is often approached with simplified boundary conditions that may not be appropriate for helical stents. The finite element method (explicit and implicit) was used to investigate three common stent expansion approaches with a focus on helical stent geometry, which differs from traditional wire mesh stent expansion. Although each of the three methods considered provided some insight into the expansion characteristics, common displacement controlled, and uniform expansion methods were not able to demonstrate the characteristic local deformations observed in expansion. A coupled stent-balloon model, although computationally expensive, was able to demonstrate the expected nonuniform deformation. To address nonuniform expansion, a progressive expansion approach has been investigated and verified numerically. This method may also provide a suitable solution for nonuniform expansion in other stent designs by minimizing loading and potential damage to the artery that can occur during stent deployment.