Covered Cheatham-Platinum Stent for Treatment of Descending Thoracic Aortic Stenosis Caused by Takayasu Arteritis in Two Children.

Takayasu arteritis (TA) is a chronic type of systemic large vessel vasculitis, mainly involving the aorta and its main branches. Both surgical and endovascular revascularization are effective methods for treating TA-related stenosis of the aorta and its branches. By December 2020, there have been very limited reports on the use of coated Cheatham-Platinum (CP) stents in the treatment of TA associated descending thoracic aortic stenosis. Two children with thoracic aortic stenosis caused by TA who received the covered CP stent in Xuanwu Hospital of Capital Medical University were reported. The follow-up time was 1.5 years and 4 years, respectively. The covered cheatham-platinum (CP) stent may be an alternative treatment for TA associated children with descending aortic stenosis.

Directional atherectomy and drug-coated balloon angioplasty vs. bare nitinol stent angioplasty for femoropopliteal artery lesions.

Background: The present study evaluated the prognosis of directional atherectomy (DA)+drug-coated balloon (DCB) angioplasty for femoropopliteal artery lesions compared with bare nitinol stent (BNS). Patients and methods: This retrospective cohort study included patients with femoropopliteal artery lesions who underwent percutaneous endovascular surgery between January 2016 and June 2019. The primary outcome was the primary patency rate after 12, 24, and 36 months; the secondary outcomes comprised incidence of flow-limiting dissections, technical success, limb salvage, and all-cause death. Results: During the study period, 110 (44%) patients underwent DA+DCB, and 140 (56%) patients underwent bare nitinol stent (BNS). There were no differences in the 12- and 24-month patency rates of the two groups (98.2% vs. 93.6% and 68.2% vs. 60.0%, both p>.05). The 36-month primary patency rate in the DA+DCB group was significantly higher than that of the BNS group (27.3% vs. 15.7%, p=.003). The technical success rate and all-cause death were similar between groups (p>.05). Flow-limiting dissections occurred more frequently in the BNS group than in the DA+DCB group (27.9% vs. 10.9%, p=.033). After adjustment for potential confounders, such as sex, smoking, hypertension, hyperlipidemia, ABI after surgery, TASC II B, lesion length ≥15 cm, two-vessel runoff, and three-vessel runoff, the HR for primary patency rate comparing BNS to DA+DCB was 2.61 (95%CI: 1.61-4.25). Conclusions: In this retrospective cohort study, DA+DCB was associated with a higher 30-month primary patency rate and a lower flow-limiting dissection incidence than BNS.

Midterm Outcome of Directional Atherectomy Combined with Drug-Coated Balloon Angioplasty Versus Drug-Coated Balloon Angioplasty Alone for Femoropopliteal Arteriosclerosis Obliterans.

BACKGROUND: The "leave nothing behind" strategies have been becoming a popular treatment for femoropopliteal arteriosclerosis obliterans. Atherectomy before drug-coated balloon (DCB) angioplasty may have an advantage in improving the efficiency of drug delivery into the blood vessel wall. This study aimed to compare the therapeutic effects of directional atherectomy combined with DCB angioplasty with DCB angioplasty alone in the treatment of femoropopliteal arteriosclerosis obliterans. METHODS: Patients with femoropopliteal arteriosclerosis obliterans who received endovascular therapy from June 2016 to June 2018 in our hospital and presented with life-limiting claudication or severe chronic limb ischemia comprised the study cohort. The patients were randomized to receive directional atherectomy combined with DCB angioplasty (n = 45) or DCB alone (n = 49). Ninety-four patients were enrolled in our study with 72 males, and the mean age was 67 ± 10 years. The mean lesion length was 112 ± 64 mm. RESULTS: There were no significant differences in the baseline characteristics of patients and lesions between the 2 randomized groups (P > 0.05). Flow-limiting dissections occurred more frequently in the DCB group (n = 12; 24.5%) than in the DA-DCB group (n = 2; 4.4%; P = 0.006). The technical success rate in the DA-DCB group was superior to that in the DCB group (95.6% vs. 75.5%, P = 0.006). The mean follow-up duration was 16.7 ± 6.1 months in the DCB group and 15.3 ± 5.8 months in the DA-DCB group. No amputations were performed. The overall mortality in the DCB group was 4.1% (2/49), while all patients survived in the DA-DCB group. The 12-month and 24-month primary patencies in the DA-DCB group were greater than those in the DCB group (80.5% vs. 75.7% and 67.1% vs. 55.1%, respectively); however, using all available patency data, no significant differences over time were observed (P = 0.377). CONCLUSIONS: In this study, directional atherectomy combined with DCB angioplasty can decrease the flow-limiting dissection rate in the treatment of femoropopliteal arteriosclerosis obliterans compared with DCB angioplasty alone. There was no significant difference between the 2 groups in terms of primary patency rate which was needed to be further clarified.

Biocompatibility evaluation of heparin-conjugated poly(ε-caprolactone) scaffolds in a rat subcutaneous implantation model.

Vascular grafts prepared from synthetic polymers have serious shortcomings that can be resolved by surface modification, such as by immobilizing heparin. In this study, the mechanical properties, biocompatibility, anticoagulation property, and water contact angle of two heparin-conjugated poly(ε-caprolactone) scaffolds (PCL-hexamethylendiamine-heparin, PCL-HMD-H. PCL-lysine-heparin, PCL-LYS-H) were compared to identify a preferred heparin conjugation method. An evaluation of the subcutaneous tissue biocompatibility of the scaffolds demonstrated that PCL-HMD-H had better endothelial cell proliferation than the PCL-LYS-H and was therefore a promising scaffold candidate for use in vascular tissue-engineering.

Vascular Remodeling Process of Heparin-Conjugated Poly(ε-Caprolactone) Scaffold in a Rat Abdominal Aorta Replacement Model.

In the field of vascular graft research, poly-ε-caprolactone (PCL) is used owing to its good mechanical strength and biocompatibility. In this study, PCL scaffold was prepared by electrospinning and surface modification with heparin via hexamethylenediamine. Then the scaffolds were implanted into the infrarenal abdominal aorta of Wistar rats and contrast-enhanced micro-ultrasound was used to monitor the patency of grafts after implantation. These grafts were extracted from the rats at 1, 3, and 6 months for histological analysis, immunofluorescence staining, and scanning electron microscopy observation. Although some grafts experienced aneurysmal change, results showed that all implanted grafts were patent during the course of 6 months and these grafts demonstrated well-organized neotissue with endothelium formation, smooth muscle regeneration, and extracellular matrix formation. Such findings confirm feasibility to create heparin-conjugated scaffolds of next-generation vascular grafts.

In vivo evaluation of safety and performance of a tapered nitinol venous stent with inclined proximal end in an ovine iliac venous model.

A tapered stent with inclined proximal end is designed for fitting the iliac anatomically. The aim of the present study was to evaluate the safety and performance of the new stent in ovine left iliac veins. The experiment was performed in 30 adult sheep, and one nitinol-based VENA-BT® iliac venous stent (KYD stent) was implanted into each animal's left common iliac vein. Follow-up in all sheep consisted of angiographic, macroscopic, and microscopic examinations at Day 0 (< 24 h), Day 30, Day 90, Day 180 and Day 360 post-stenting (six animals per each time-point). 30 healthy ~ 50 kg sheep were included in this study and randomly divided into five groups according to the follow-up timepoint. All stents were implanted successfully into the left ovine common iliac vein. No significant migration occurred at follow-up. There is no statistically significant difference between the groups (p > 0.05), indicating no serious lumen loss occurred during the follow-up period. Common iliac venous pressure was further measured and the results further indicated the lumen patency at follow-up. Histological examinations indicated that no vessel injury and wall rupture, stent damage, and luminal thrombus occurred. There was moderate inflammatory cell infiltration around the stent in Day-0 and Day-30 groups with the average inflammation score of 2.278 and 2.167, respectively. The inflammatory reaction was significantly reduced in Day-90, Day-180 and Day-360 groups and the average inflammation scores were 0.9444 (p < 0.001, Day-90 vs Day-0), 1.167 (p < 0.001, Day-180 vs Day-0) and 0.667 (p < 0.001, Day-90 vs Day-0), respectively. The microscopic examinations found that the stents were well covered by endothelial cells in all follow-up time points. The results suggested that the KYD stent is feasible and safe in animal model. Future clinical studies may be required to further evaluate its safety and efficacy.

Poly(ethylene glycol) Hydrogels with the Sustained Release of Hepatocyte Growth Factor for Enhancing Vascular Regeneration.

The surface modification of biologically active factors on tissue-engineering vascular scaffold fails to fulfill the mechanical property and bioactive compounds' sustained release in vivo and results in the inhibition of tissue regeneration of small-diameter vascular grafts in vascular replacement therapies. In this study, biodegradable poly(ε-caprolactone) (PCL) was applied for scaffold preparation, and poly(ethylene glycol) (PG) hydrogel was used to load heparin and hepatocyte growth factor (HGF). In vitro analysis demonstrated that the PCL scaffold could inhibit the heparin release from the PG hydrogel, and the PG hydrogel could inhibit heparin release during the process of PCL degradation. Finally, it results in sustained release of HGF and heparin from the PCL-PG-HGF scaffold. The mechanical property of this hybrid scaffold improved after being coated with the PG hydrogel. In addition, the PCL-PG-HGF scaffold illustrated no inflammatory lesions, organ damage, or biological toxicity in all primary organs, with rapid organization of the endothelial cell layer, smooth muscle regeneration, and extracellular matrix formation. These results indicated that the PCL-PG-HGF scaffold is biocompatible and provides a microenvironment in which a tissue-engineered vascular graft with anticoagulant properties allows regeneration of vascular tissue (Scheme 1). Such findings confirm the feasibility of creating hydrogel scaffolds coated with bioactive factors to prepare novel vascular grafts.

Endovascular stenting vs. extrathoracic surgical bypass for symptomatic subclavian steal syndrome.

PURPOSE: To analyze the immediate and long-term outcomes of endovascular stenting vs. extrathoracic surgical bypass for subclavian steal syndrome. METHODS: From 1989 to 2010, 252 consecutive patients (173 men; mean age 62 years) with vertebrobasilar and upper extremity symptoms of subclavian steal were treated with balloon-expandable stents (n=148) or extrathoracic surgical bypasses (n=104: 71 axilloaxillary and 33 carotid-subclavian) using polytetrafluoroethylene grafts. RESULTS: The technical success rate was 97.3% in the stent group vs. 99.0% for the bypass group (p=0.605). There was no perioperative mortality or any permanent neurological deficit in either group. The overall perioperative complication rate was 6.1% in the stent group vs. 9.6% in the bypass group (p=0.295). The 10-year target vessel revascularization rate was 46.6% for stenting vs. 5.8% for bypass (p<0.001). The cumulative primary patency rates at 1, 3, 5, and 10 years were 91%, 78%, 67%, and 49% for the stent group vs. 99%, 97%, 95%, and 89% for the bypass group (p<0.001). The cumulative secondary patency rates were 95%, 91%, 86%, and 64%, respectively, for the stent group vs. 99%, 99%, 98%, and 94% for the bypass group (p=0.001). No difference was detected in overall survival curves between the groups (p=0.527). CONCLUSION: Both endovascular stenting and extrathoracic surgical bypass are safe and effective treatments for subclavian steal syndrome in the short and medium term; however, extrathoracic surgical bypasses are more durable in the long term.

A Retrospective Comparative Study of Twelve-Month Clinical Outcomes for Drug-Coating Balloon Angioplasty and Stent Implantation in Treating Patients with Popliteal Obstructive Lesions.

PURPOSE: Despite increased interest in treating superficial femoral and popliteal arteries with endovascular technology, there is little data regarding comparative results of different treatment modalities in the popliteal artery. It was hypothesized that to improve clinical outcomes in this segment, drug-coating balloon (DCB) angioplasty would not be inferior to stent implantation. METHODS: The records of consecutive Chinese patients with popliteal lesions who were treated with DCB or stenting between June 2016 and February 2017 were retrospectively reviewed. The preoperative demographic, lesion characteristics and postoperative outcomes were compared and statistically analyzed. All patients were divided into different subgroups according to the degree of calcium or degree of ischemia. RESULTS: One hundred two consecutive patients with popliteal lesions were treated with DCB or stenting and 95 (93.1%) completed a follow-up. Critical limb ischemia was present in 70.5% and occlusions were present in 61.1% of patients. DCB angioplasty was performed on 43 patients and angioplasty with primary stenting was performed on 52 patients. There was no difference in twelve-month primary patency (79.1% vs 82.7%; P = 0.687), secondary patency (95.3% vs 94.2%; P = 0.808) and amputation-free survival (93.0% vs 94.2%; P = 0.825) between the DCB group and stent groups. In patients with severe calcium, the twelve-month primary patency (61.1% vs. 79.2%; P = 0.239) and amputation-free survival (83.3% vs 87.5%; P = 0.739) did not differ between the DCB and stent groups. CONCLUSIONS: This study demonstrates that DCB treatment in Chinese patients with popliteal atherosclerotic occlusive lesions can be associated with similar twelve-month patency and amputation-free survival compared to stenting, even in patients with severe calcification. LEVEL OF EVIDENCE: Level 3a, Non-randomized follow-up study.

A systematic review and meta-analysis comparing the efficacy of cyanoacrylate ablation over endovenous thermal ablation for treating incompetent saphenous veins.

OBJECTIVES: The aim of this study was to systemically review and analyze the efficacy of cyanoacrylate ablation (CA) in comparison with endovenous thermal ablation (ETA) for the treatment of incompetent saphenous veins. METHODS: A systematic literature search was conducted using databases of Pubmed, Embase, and Cochrane Library from the times of their inception to April 2020. Studies were selected based on inclusion and exclusion criteria after assessing the risk of bias in comparative studies with Cochrane and rating quality of evidence with the GRADE methodology. The meta-analysis was carried out using the Review Manager 5.4 program to conduct homogeneity tests. RESULTS: One cohort study and three randomized controlled trials (RCT), including a total of 1457 participants were included in the meta-analysis. ETA included endovenous laser ablation (ELVA) and radiofrequency ablation (RFA) in the selected studies. Comparison between CA and a combination of EVLA and RFA or RFA alone were carried out in two of RCTs, while comparison between CA with EVLA was conducted in one RCT and the cohort study. There was no statistical difference in closure rates between CA and ETA after pooled analysis. Similar symptom alleviation observed between different groups. However, the CA group showed a lower ecchymosis rate than RFA and a significantly lower incidence of adverse events, such as ecchymosis, phlebitis and paresthesia, than EVLA. Compared with ETA, the patients received CA treatment exhibited lower pain scores in a shorter procedure duration without needing compression stocking, returned to normal life sooner, and had significantly better quality of care. There was no significant difference in the number needed to treat for additional therapy after three months of follow-up between groups. CONCLUSIONS: This meta-analysis indicates that CA has better overall outcomes than ETA and offers superior clinical benefits in the treatment of incompetent saphenous veins.

Gelatin coating promotes in situ endothelialization of electrospun polycaprolactone vascular grafts.

Rapid endothelialization is crucial for in situ tissue engineering vascular grafts to prevent graft failure in the long-term. Gelatin is a promising nature material that can promote endothelial cells (ECs) adhesion, proliferation, and migration. In this study, the internal surface of electrospun polycaprolactone (PCL) vascular grafts was coated with gelatin. Endothelialization and vascular wall remolding were investigated by imaging and histological studies in the rat abdominal aorta replacement model. The endothelialization of heparinized gelatin-coated PCL (GP-H) vascular grafts was more rapid and complete than heparinized PCL (P-H) grafts. Intimal hyperplasia was milder in the GP-H vascular grafts than the P-H vascular grafts in the long-term. Meanwhile, smooth muscle cells (SMCs) and extracellular matrix (ECM) regeneration were better in the GP-H vascular grafts. By comparison, an aneurysm was observed in the P-H group in 6 months. Calcification was observed in both groups. All vascular grafts were patient after implantation in both groups. Our results showed that gelatin coating on the internal surface of PCL grafts is a simple and effective way to promote endothelialization. A more rapid endothelialization and complete endothelium can inhibit intimal hyperplasia in the long-term.

Drug-Coated Balloon Angioplasty and Debulking for the Treatment of Femoropopliteal In-Stent Restenosis: A Systematic Review and Meta-Analysis.

The purpose of this article was to compare the efficiency and safety of drug-coated balloon angioplasty (DCB) and atherectomy with percutaneous transluminal angioplasty (PTA) in patients with femoropopliteal in-stent restenosis (ISR). Pubmed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) (all up to March 2019) were searched systematically. Trial sequential analysis (TSA) was conducted. 5 studies with 599 participants were included. Compared with PTA, DCB significantly increased the rate of patency (6 months: RR 1.65, 95% CI 1.30 to 2.09, P < 0.01; 12 months: RR 2.38, 95% CI 1.71 to 3.30, P < 0.01) and the rate freedom from target lesion revascularization (TLR) (6 months: RR 1.18, 95% CI 1.09 to 1.28, P < 0.01; 12 months: RR 1.56, 95% CI 1.33 to 1.82, P < 0.01) at 6 and 12 months follow-up, and the TSA results showed these outcomes were reliable. The rate of clinical improvement by ≥1 Rutherford category in the DCB group was higher than that in the PTA group (6 months: RR 1.35, 95% CI 1.03 to 1.75, P = 0.03; 12 months: RR 1.46, 95% CI 1.17 to 1.82, P < 0.01) at 6 and 12 months. There is no statistically difference of ABI, all-cause mortality, and incidence of amputation between DCB group and PTA group (MD 0.03, 95% CI -0.03 to 0.08, P = 0.40; RR 1.24, 95% CI 0.46 to 3.34, P = 0.67; RR 0.32, 95% CI 0.01 to 7.61, P = 0.48). Compared with PTA, the rate of patency and freedom from TLR in the laser atherectomy (LD) group was higher than that in the PTA group (patency: 6 months: RR 1.28, 95% CI 1.01 to 1.64, P < 0.05, 12 months: RR 2.25, 95% CI 1.14 to 4.44, P < 0.05; freedom from TLR: 6 months: RR 1.27, 95% CI 1.05 to 1.53, P = 0.01, 12 months: RR 1.59, 95% CI 1.12 to 2.25, P = 0.01) at 6 and 12 months follow-up. In conclusion, DCB and LD had superior clinical (freedom from TLR and clinical improvement) and angiographic outcomes (patency rate) compared with PTA for the treatment of femoropopliteal ISR. Moreover, DCB and LD had a low incidence of amputation and mortality and were relatively safe methods.

Surgical treatment of 82 patients with diabetic lower limb ischemia by distal arterial bypass.

BACKGROUND: Diabetic lower limb ischemia is a serious complication of diabetes mellitus. This study was conducted to investigate the effectiveness of distal arterial bypass treatment in diabetic patients with lower limb ischemia. METHODS: From July 2000 to July 2004, 96 lower limbs of 82 diabetic patients (type 2) with severe lower limb ischemia were treated in Xuan Wu Hospital. Arterial bypass with femoro-popliteal polytetrafluoroethylene (PTFE) and graft-tibial autologous grafts was performed on 31 limbs (32.3%). Popliteal-tibial artery bypass alone was performed on 22 limbs (22.9%). Combined iliac artery stenting, femoro-popliteal artery PTFE graft bypass, and graft-tibial artery autologous graft bypass was performed on 12 limbs (12.5%), and femoro-tibial artery graft bypass was performed on 10 limbs (10.4%). Popliteal-tibial-pedal artery graft bypass was performed on 7 limbs (7.3%). RESULTS: Arterial grafts in 92 limbs of 79 patients were patent on discharge. Three patients with 4 ischemic limbs (3.7%) died of respiratory failure 12 hours, 3 days and 7 days after operation respectively. Early operation success rate was 96.3% (79/82). Graft patency rate of patients on discharge was 95.8% (92/96). The short-term total effectiveness rate was 83.3% (80/96). Foot ulcer healing rate was 35.7% (10/28). 97.4% (75/77) patients were followed up for a mean of 13.5 months. The long-term total effective rate was 80.7% (71/88). The total amputation rate was 4.5% (4/88). Mortality was 4.5%. The total graft patency rate was 90.9% (80/88). CONCLUSION: In the treatment of diabetic foot, distal lower limb arterial bypass can help to avoid amputation or lower the amputation level, and may promote foot ulcer healing and improve patient's quality of life.

The penetration and phenotype modulation of smooth muscle cells on surface heparin modified poly(ɛ-caprolactone) vascular scaffold.

The tubular porous poly(ɛ-caprolactone) (PCL) scaffold was fabricated by electrospinning. After then, the scaffold's surface was firstly eroded by hexyldiamine to endow amine group, and heparin was covalently grafted to the surface to get surface heparin modified scaffold (ShPCL scaffold). It was found that ShPCL scaffold can induce smooth muscle cells (SMCs) to penetrate the scaffold surface, while the SMCs cannot penetrate the surface of PCL scaffold. Subsequently, the rabbit SMCs were seeded on the ShPCL scaffold and cultured for 14 days. It was found the expression of α-smooth muscle actin in ShPCL scaffold maintained much higher level than that in culture plate, which implied the SMC differentiation in ShPCL scaffold. Furthermore, the immunefluorescence staining of the cross-sections of ShPCL scaffold exhibited the expression of calponin in ShPCL scaffold can be detected after 7 and 14 days, whereas the expression of smooth muscle myosin heavy chain can also be detected at 14 days. These results proved that penetrated SMCs preferably differentiated in to contractile phenotype. The successful SMC penetration and the contractile phenotype expression implied ShPCL scaffold is a suitable candidate for regenerating smooth muscle layer in vascular tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2806-2815, 2017.

A vascular tissue engineering scaffold with core-shell structured nano-fibers formed by coaxial electrospinning and its biocompatibility evaluation.

In this article, a tubular vascular tissue engineering scaffold with core-shell structured fibers was produced by coaxial electrospinning at an appropriate flow rate ratio between the inner and outer solution. PCL was selected as the core to provide the mechanical property and integrity to the scaffold while collagen was used as the shell to improve the attachment and proliferation of vascular cells due to its excellent biocompatibility. The fine core-shell structured fibers were demonstrated by scanning electron microscope and transmission electron microscope observations. Subsequently, the collagen shell was crosslinked by genipin and further bound with heparin. The crosslinking process was confirmed by the increasing of tensile strength, swelling ratio and thermogravimetric analysis measurements while the surface heparin content was characterized by means of a UV-spectrophotometer and activated partial thromboplastin time tests. Furthermore, the mechanical properties such as stitch strength and bursting pressure of the as-prepared scaffold were measured. Moreover, the biocompatibility of the scaffold was evaluated by cytotoxicity investigation with L929 cells via MTT assay. Endothelial cell adhesion assessments were conducted to reveal the possibility of the formation of an endothelial cell layer on the scaffold surface, while the ability of smooth muscle cell penetration into the scaffold wall was also assessed by confocal laser scanning microscopy. The as-prepared core-shell structured scaffold showed promising potential for use in vascular tissue engineering.

The fabrication of double layer tubular vascular tissue engineering scaffold via coaxial electrospinning and its 3D cell coculture.

A continuous electrospinning technique was applied to fabricate double layer tubular tissue engineering vascular graft (TEVG) scaffold. The luminal layer was made from poly(ɛ-caprolac-tone)(PCL) ultrafine fibers via common single axial electrospinning followed by the outer layer of core-shell structured nanofibers via coaxial electrospinning. For preparing the outer layernano-fibers, the PCL was electrospun into the shell and both bovine serum albumin (BSA) and tetrapeptide val-gal-pro-gly (VAPG) were encapsulated into the core. The core-shell structure in the outer layer fibers was observed by transmission electron microscope (TEM). The in vitro release tests exhibited the sustainable release behavior of BSA and VAPG so that they provided a better cell growth environment in the interior of tubular scaffold wall. The in vitro culture of smooth muscle cells (SMCs) demonstrated their potential to penetrate into the scaffold wall for the 3D cell culture. Subsequently, 3D cell coculture was conducted. First, SMCs were seeded on the luminal surface of the scaffold and cultured for 5 days, and then endothelial cells (ECs) were also seeded on the luminal surface and cocultured with SMCs for another 2 days. After stained with antibodies, 3D cell distribution on the scaffold was revealed by confocal laser scanning microscopy (CLSM) where ECs were mainly located on the luminal surface whereas SMCs penetrated into the surface and distributed inside the scaffold wall. This double layer tubular scaffold with 3D cell distribution showed the promise to develop it into a novel TEVG for clinical trials in the near future.