A novel tissue-engineered stent graft combining decellularized scaffold and bioresorbable stent: a pilot feasibility study in a porcine model.

In 458 BC, a prominent Roman leader named Lucius Quintius Cincinnatus was unique in his behavior. Cincinnatus served his country when he was needed and, after fulfilling his duty, he returned to his private life.1 We now see a new medical device, a biodegradable stent, that mimics this historical figure. The 2 main functions of a stent, treatment of dissection and prevention of restenosis, refer to 2 events that occur and progress in a set frame of time. Coronary dissections are effectively contained by stent insertion and undergo a healing process, with the majority of cardiac events occurring in the first 6 months.2 In-stent restenosis also occurs within the first 6 months.3 Therefore, a permanent prosthesis that is in place beyond this initial period has no clear function. Besides lacking a well-defined function, are there any negative aspects related to the presence of a permanent coronary implant? Zidar et al4 stated that one of the main reasons to develop a biodegradable stent was the short-term need for a stent and the potential long-term complications of metal stents. Kimura et al3 demonstrated, with an extended angiographic follow-up of 3 years, that the presence of a metallic stent does not seem to be associated with lesion progression or accelerated atherosclerosis of the treated site after 6 months. In fact, late improvement in luminal diameter seems to occur between 6 months and 3 years. The Belgian Netherlands Stent Study (BENESTENT I) recently extended its follow-up to 5 years and demonstrated a sustained and persistent benefit of the stent.5 If no demonstrable complications exist with a permanent intracoronary implant, can the question be turned around by asking, “What are the benefits of not having a permanent coronary implant?” Two answers can be given. 1. Coronary stenting freezes recoil, …

To the Editor: A 35-year-old man who smoked for 15 years suffered from chest pain 12 days ago before admission. He was diagnosed as myocardial infarction. Thrombolytic therapy was given consequently. The electrocardiogram showed sub-acute inferior wall myocardial infarction. Echocardiogram showed attenuated constriction of the inferior wall with an ejection fraction of 59%. On September 5, 2013, he was treated with a XINSORB scaffold in right coronary artery (RCA). Angiography revealed a regional lesion with severe stenosis in the distal RCA. No lesions were detected in the rest segment of coronary arteries [Figure 1a]. Intravascular ultrasound (IVUS) confirmed abundant fibrous plaques with plaque rupture in the lesion site [Figure 1b]. After predilatation, a XINSORB scaffold whose size was 3.0 mm × 18.0 mm was implanted. Repeated angiography showed the scaffold was well deployed. Minimal luminal diameter (MLD) was 2.95 mm while in-scaffold residual stenosis was 7.4% [Figure 1c]. No malapposition was detected under IVUS [Figure 1d]. The scaffold area was 6.62 ± 0.57 mm2. The patient was discharged 2 days after the procedure. Neither major adverse cardiac events nor stent thrombus related events were recorded. During the next 6 months, the patient recovered well without recurrent ischemic symptoms. Dual antiplatelet therapy was maintained. Angiography at 6-month follow-up showed the scaffold remained patent without significant neointimal hyperplasia. In-scaffold MLD and percent of diameter stenosis was 2.73 mm and 8.8% respectively, therefore the in-scaffold late luminal loss was calculated as 0.22 mm [Figure 1e]. The area of scaffold, lumen and neointima was 6.69 ± 0.52 mm2, 6.44 ± 0.46 mm2 and 0.24 ± 0.11 mm2 under IVUS [Figure 1f]. No difference was detected between the scaffold area after the procedure and 6-month follow-up (P = 0.82). Optical coherence tomography showed that all struts remained the appearance of preserved box. The struts were embedded in neointima and well-apposed. Figure 1 (a and b) Regional lesion with severe stenosis in the distal RCA; IVUS showed abundant fibrous plaques; (c and d) Final result after treated with a XINSORB scaffold; the struts were well apposed under IVUS; (e and f) The vessel remained patent at 6-month ... Bioresorbable XINSORB scaffold is a balloon-expandable stent system. The scaffold is composed of poly-L-lactic acid (PLLA) as its backbone. Poly-D-L-lactic acid mixed with PLLA is coated on the scaffold surface, containing sirolimus and controlling its elution. The dose of sirolimus is 8 μg/mm. About 80% of anti-proliferative drugs are eluted in 28 days ex vivo. Thickness of strut is 160 μm. The device is stored at 4°C.[1,2] The safety and effectiveness of bioresorbable scaffold (BRS) are confirmed by ABSORB studies.[3,4,5] The XINSORB scaffold is the first domestically made BRS by Chinese company. Promising clinical and angiographic outcomes have been established in this patient. Some advice should be followed when using this device. First, mandatory predilatation must be performed. A balloon to artery ratio of 1:1 is recommended. Second, the scaffold should not be deployed until 90 s after it exposes to the blood. Third, the scaffold should be slowly expanded from 0 to 4 atm during the first 10 s. After that, the scaffold can be fully expanded at a pressure not exceeding 14 atm for 30 s. Lastly, postdilatation was allowed with a 3.0 mm or 3.25 mm noncompliance balloon that was shorter than the implanted scaffold. This is the first implantation of a domestic BRS. Currently, a single-arm clinical trial of XINSORB scaffold is being carried out in Zhongshan Hospital, Fudan University and Chinese People's Liberation Army General Hospital. Large scale and long-term follow-up are required to confirm the substantial benefits of XINSORB scaffold in treating coronary lesions of Chinese population.

The modern open surgical management of abdominal aortic aneurysm (AAA) has changed little since its inception in the 1950s. Endoaneurysmorrhaphy, first described by Rudolph Matas in 1888, involved ligating the branches of an aneurysm from within the aneurysm sac. Approximately 25 years later at the

Evaluation of the Biodegradable Peripheral Igaki-Tamai Stent in the Treatment of De Novo Lesions in the Superficial Femoral Artery: The GAIA Study

This study aimed to develop a new biodegradable stent for peripheral artery disease (PAD) that could provide sufficient radial force to maintain long-term patency and flexibility. All self-expandable hybrid biodegradable stents were designed by using a knitting structure composed of poly-L-lactic acid (PLLA) and nitinol. Four different types of stents were implanted in 20 iliac arteries in 10 mini pigs as follows: a bare-metal stent (BMS) (group 1, n = 5), a drug-free hybrid stent (group 2, n = 5), a 50% (50 : 100, w/w) paclitaxel (PTX)/poly-lactide-co-glycolic acid (PLGA; fast PTX-releasing form) hybrid stent (group 3, n = 5), and a 30% (30 : 100, w/w) PTX/PLGA (slow PTX-releasing form) hybrid stent (group 4, n = 5). We performed follow-up angiography and intravascular ultrasonography (IVUS) at 4 and 8 weeks. In a comparison of groups 1, 2, 3, and 4, less diameter stenosis was observed in the angiographic analysis for group 4 at the 4-week follow-up (19.0% ± 12.7% versus 39.3% ± 18.1% versus 46.8% ± 38.0% versus 4.8% ± 4.2%, resp.; p = 0.032). IVUS findings further suggested that the neointima of the patients in group 4 tended to be lesser than those of the others. Our new biodegradable 30% PTX/PLGA (slow-releasing form) stent showed more favorable results for patency than the other stent types.

ABSTRACTBioresorbable scaffolds have the potential to overcome several problems associated with metallic stents. Bioresorbable poly-L-lactic acid (PLLA) scaffold implantation for the treatment of peripheral artery disease has already been reported in animal models and clinical trials; however, no studies comparing PLLA scaffolds and bare metal stents (BMSs) with regard to early vascular morphological changes, identified using intravascular ultrasound (IVUS) analysis, have been reported. In this study, PLLA scaffolds and BMSs were implanted bilaterally in iliac arteries of five miniature pigs. Digital subtraction angiography and IVUS were performed before and immediately after stent implantation and at 6-week follow-up. All PLLA scaffolds and BMSs were patent at 6-week follow-up. Per IVUS analysis, the percent area stenosis did not significantly differ between PLLA scaffolds and BMSs (65.7% vs. 67.2%, P = .761). Furthermore, percent vessel lumen change also did not differ significantly. Neointima formation (the neointimal area plus medial area) was significantly less with PLLA scaffolds than with BMSs (15.65 mm2 vs. 25.69 mm2, P < .001). In conclusion, based on IVUS results, short-term results after stent implantation in porcine iliac arteries were comparable between PLLA scaffolds and BMSs. Therefore, PLLA scaffolds are safe and feasible for implantation in peripheral arteries.

The influence of smoking on endovascular abdominal aortic aneurysm repair

Bioresorbable Scaffold for Treatment of Coronary Artery Lesions: Intravascular Ultrasound Results From the ABSORB Japan Trial

Regulatory TEVAR clinical trials

A novel double opposed helical (DH) biodegradable stent was designed and fabricated for CHD applications. The primary objective was to evaluate the feasibility of DH stent delivery and deployment in rabbit external iliac arteries (EIA). Secondary objectives were to assess stent patency, thrombosis and inflammation at 1-week and 1-month follow-up. Biodegradable stents have largely been designed for adult cardiovascular indications, to avoid long term complications of permanent implants. A growing child with congenital heart disease (CHD) would especially derive substantial benefit from this technology. DH stents were manufactured to 3, 4, 5, and 6-mm diameter with poly-l-lactic acid (PLLA) fibers. Bench test analysis was performed. Six DH stents were implanted in rabbit EIA. Vessel patency was assessed at 1-week and 1-month follow-up with repeat angiography, intravascular ultrasound (IVUS). Histopathological evaluation was performed. The elastic recoil and collapse pressure of DH stents were comparable to conventional metal stents. All DH stents were successfully delivered and implanted with good apposition to the vessel wall and no collapse of the proximal, mid or distal ends. All stented vessels remained patent. No acute or early stent thrombosis was noted. Histopathology showed minimal inflammatory response and mild neointimal proliferation at 1 month follow-up. In vitro results of DH PLLA biodegradable stents are comparable to conventional metal stents. The pilot animal study confirms the delivery and deployment of the DH stents to the desired location. The DH design can be used to fabricate larger diameter stents needed for CHD.

This study aimed to investigate clinical outcomes following bioresorbable scaffold (BRS) optimized with intravascular ultrasound (IVUS), and furthermore expansion of BRS in calcific lesions. Although IVUS use has contributed to improved clinical outcomes with metallic stent implantation, it is unclear if this is also true with regards to BRS, especially in calcified lesions. Between May 2012 and April 2015, 291 lesions in 198 patients were treated with BRS with IVUS use. We evaluated overall clinical outcomes at 1-year and investigated the expansion and eccentricity index of BRS amongst quadrants categorized by calcium arc (CA) every 90-degrees. The rates of major adverse cardiac events were 5.4% (at 6 months) and 10.7% (at 12 months). TLR was observed in 3.1% at 6-month and 7.5% at 12-month follow up. Although there was a significant difference among quadrants regarding to eccentricity of calcium (0°≦CA < 90°: 0.82 ± 0.09, 90°≦CA < 180°: 0.75 ± 0.12, 180°≦CA < 270°: 0.78 ± 0.11, and 270°≦CA≦360°: 0.79 ± 0.09, ANOVA P = 0.002), the BRS expansion index [minimal scaffold area (MSA) divided by BRS area expanded at a nominal pressure] was comparable between quadrants. The use of IVUS to optimize BRS implantation results in favorable clinical outcomes even for complex lesions. Although eccentric calcium distribution resulted in asymmetric expansion of BRS, the final MSA was comparable irrespective of calcium distribution. © 2016 Wiley Periodicals, Inc.

Treatment options for delayed AAA rupture following endovascular repair

Complex anatomical restrictions can lead to further interventions after the emergence of a postoperative aneurysm enlargement in thoracic endovascular aortic repair (TEVAR) for a thoracoabdominal aortic aneurysm (TAAA). A 75-year-old male underwent a TEVAR for a Crawford extent I TAAA. The main device and the distal extension were placed using a fenestrated technique, outside of the instructions for use. The aneurysm expanded because of an endoleak and stent graft migration; and was surgically repaired by fully salvaging the previous endografts 38 months after the first TEVAR. However, the distal extension, which was the proximal anastomosis site with a prosthetic graft, became completely dislocated from the main device eight months after the open surgical conversion, resulting again in the enlargement of the aneurysm. An additional TEVAR was successfully performed to correct the dislocated stent graft. An appropriate treatment strategy is crucial to prevent multiple reinterventions for TAAA with complex anatomical restrictions.

Newer generation bioresorbable scaffolds (BRSs) with thinner struts and improved deliverability are expected to enhance safety and efficacy profiles. Bioheart (Bio-Heart, Shanghai, China) BRS is constructed from a PLLA (poly-l-lactic acid) backbone coated with a PDLLA (poly D-l-lactic acid) layer eluting sirolimus. We report 2-year serial intracoronary imaging findings. In this first-in-human study, 46 patients with single de novo lesions in native coronary vessels (vessel size 3.0-3.75mm, lesion length ≤ 25mm) were enrolled at a single institution. Baseline intravascular ultrasound (IVUS) and post-implantation IVUS and optical coherence tomography (OCT) examinations were mandatory. After successful implantations of BRS, the 46 patients were randomized to two different follow-up cohorts in a 2:1 ratio. Thirty patients in cohort 1 had to undergo angiography, IVUS, and OCT follow-ups at 6 and 24months, respectively. The 16 patients in cohort 2 underwent the same types of imaging follow-ups at 12 and 36months, respectively. Clinical follow-ups were scheduled uniformly in both cohorts at 1, 6, and 12months and annually up to 5years for all patients. Between August and November 2016, a total of 54 patients were assessed. However, 8 patients could not meet all the inclusion criteria; thus, the remaining 46 patients (age 57.5 ± 8.7 years, 34.8% female, 50.0% with unstable angina, 26.1% diabetics) with 46 target lesions were enrolled in this study. All patients in both cohorts were required to complete clinical follow-up uniformly and regularly. In cohort 1, one patient had definite scaffold thrombosis within 6months of follow-up; thus, after 6months, cohort 1 had 96.7% patients . Imaging follow-up was available in 24 patients, and in-scaffold late loss was 0.44 ± 0.47 mm; intracoronary imaging confirmed the late loss was mainly due to to neointimal hyperplasia, but not scaffold recoil. Serial 2-year clinical and imaging follow-up results confirmed the preliminary safety and efficacy of Bioheart BRS for treatment of simple coronary lesions.

The Relationship between Temporal Changes in Proximal Neck Angulation and Stent-Graft Migration after Endovascular Abdominal Aortic Aneurysm Repair