Native Artery Research Articles

Acute Aortic Occlusion: A Nationwide Cohort Study

Introduction: Acute aortic occlusion (AAO) is a rare and potentially catastrophic event. The aim was to extend the understanding of this condition, and to study time-trends and long-term survival. Methods: A well validated nationwide vascular database, where patients had been entered prospectively, was used to identify the cases, and a cross-link to the Population Registry to study long-term survival. Results: During the 21-year study-period (1994-2014), 715 patients had been treated for AAO with a yearly incidence of 3.7 per million inhabitants. Mean age was 69.7 years, 50.5% were women and mean follow-up was 5.2 years. The aetiology for AAO was in-situ thrombosis in 458 patients (64.1%), saddle embolus in 152 (21.3%), and occluded grafts/stents/stentgrafts in 105 (14.7%). The proportion of occluded grafts/stents/stentgrafts increased during the study period with a simultaneous reduction in the proportion of in-situ thrombosis, the proportion of saddle embolus was relatively unaltered over time. Grafts/stents/stentgrafts were occluded after a mean of 39.2 months from initial surgery. Most patients (81.2%) presented with bilateral acute limb ischaemia. The most commonly used methods for revascularization were thrombo-embolectomy (32.0%), thrombolysis (22.4%), axillary-bifemoral bypass (18.9%) and aorto-biilical/bifemoral bypass (18.2%). The choice of revascularization technique depended on the aetiology of the occlusion. Amputation was required in 8.6% of the cases and 19.9% of the patients died within the first month after surgery. The 30-days mortality rate was lower after occluded grafts/stents/stentgrafts (9.5%) and higher in the saddle embolus group (30.9%, p<0.001). There was a reduction in overall 30-days mortality over time (25.0% 1994-2000 versus 15.3% 2008-2014, p=0.008). There were significant differences in survival between the subgroups, depending on aetiology, throughout the follow-up, although the difference occurred early after the event (log-rank, p<0.001, see the attached Figure). Conclusion: Mortality after AAO is high, but improving over time. The proportion of AAO secondary to occluded grafts/stents/stentgrafts increases, and the proportion secondary to native artery thrombosis decreases, over time.

In Vivo Tissue-Engineered Allogenic “Biotube” Vascular Grafts Could Grow in a Growing Canine Model

Introduction - In pediatric surgery, size mismatch inducing between artificial vascular grafts and growing recipients vessels remains a serious problem to be solved. Biotubes are connective tissue tubes, formed by in body tissue architecture technology (IBTA), which is a novel and practical approach of regenerative medicine. Recently, we developed type C Biotubes with thick wall thickness. This study aimed to evaluate the growth potential of type C Biotubes by examining their caliber and length adaptation to growing native arteries after implantation.

World’s Smallest Calibre Microbiotube Graft: Its Growth Evaluation and Two Year Follow-up in a Rat Model

Introduction - We recently developed the world’s smallest calibre MicroBiotube vascular graft with an inner diameter of 0.6 mm. It is formed using in-body tissue architecture (iBTA) and has a high degree of patency and capacity for regeneration in the acute phase, 1 month after implantation. This report presents the growth ability of Microbiotube and the compatibility and stability of MicroBiotubes in the chronic phase of implantation for 2 years in a rat model. Methods - The MicroBiotubes (internal diameter 0.6 mm) were prepared by embedding the mould subcutaneously in rats for 2 months. An allogenic MicroBiotube was implanted into the abdominal aorta (inner diameter 0.5 mm) for its growth evaluation up to 3 months, or into the femoral arteries (inner diameter 0.5 mm) for chronic evaluation up to 2 years. Follow-up observation was performed by 7-Tesla magnetic resonance angiogram. Histological observation was performed after 1 year of implantation. Results - Growth evaluation) Monthly follow-up angiogram showed that internal diameter of MicroBiotubes (length 3 mm) was expanded to ca. 1.5 times after 3 month of implantation according to the growth of native arteries (Fig. 1). At the same time, their length was extended to ca. 1.5 times. Chronic evaluation) There was no occlusion of all patent implanted MicroBiotubes (length 5 mm, patency 75%) at 1 month after implantation up to 2 years (Fig. 2). In all observation period, no abnormal morphological changes or calcification occurred. Histological observation at 2 years showed layered vascular construction. Conclusion - This study suggests that MicroBiotubes have growth ability, high compatibility, stability, and durability as replacement grafts.

Development of an In-body-tissue-engineered Collagenous Biosheet for Regenerative Vascular Reconstruction in a Beagle Model

Introduction - Autologous pericardial tissues are commonly used for the arterial reconstruction. To overcome their limited amount, tissue-engineered material that has potential to engraft to native tissues and then grow is desired especially in pediatric surgery. In body tissue architecture (iBTA) can prepare autologous collagenous sheet-like tissues, called Biosheets, by using a patient's body as a bioreactor. Its process is simple and safe, just subcutaneously embedding a mold for about 2 months. Since Biosheet has sufficient mechanical properties they could be applied as reconstruction materials for abdominal wall or diaphragm. This study investigated the possibility of Biosheet as a regenerative vascular reconstruction material in a beagle model. Methods - Cylindrical molds (diameter 18 mm, length 7 cm) were embedded in beagles or cows (Hokkaido University) subcutaneously for 2 months. Tubular tissues were formed inside of all molds, and were harvested upon removing the mold. Canine or bovine Biosheets (size 5 x 7 cm, thickness ca. 0.6 mm) were obtained by cutting the tubular tissues at the longitudinal direction as collagenous sheet-like tissues. Arterial defects at pulmonary arteries (ca. 10 × 20 mm, 1 in photos) or descending aorta (ca. 10 x 10 mm, 2 in photos) were made and patch repair using Biosheets was performed in beagles under partial clamping. Results - In ultrasonic echo observation, little change in blood flow change occurred after the patching. Angiogram showed no elongation or stenosis at the patched region (3 in photos). Tissue migration from native artery occurred primarily on the luminal surface of the Biosheets with their degradation (4 in photos). Even in xeno implantation using bovine Biosheets after 6 months Bioisheets were almost completely disappeared and partial arterial reconstruction was observed. The function as a pulmonary or aortic artery was maintained for more than 6 months. Conclusion - Biosheet could function as a regenerative vascular repair material even at arteries or in xeno grafts.

Ultrasound Criteria for Assessment of Vertebral Artery Origins

We sought to validate ultrasound as a reliable means of assessing vessel stenosis of vertebral artery origins. We reviewed 1,135 patient charts with ultrasound of the posterior circulation performed in 2008-2015 in a single hospital. Inclusion criteria for native vessels consisted of ultrasound and digital subtraction angiography (DSA) performed within 3 months. Patients with indwelling stents were analyzed separately from native vessels. Using DSA as the gold standard, we determined sensitivity and specificity of ultrasound in detecting occlusion at vertebral artery origin. All patients with nonoccluded native vertebral artery origins were evaluated for degree of stenosis on DSA, and compared to mean flow velocity (MFV), peak systolic velocity (PSV), and end-diastolic velocity (EDV) on ultrasound. Among 218 vertebral artery origins in 139 patients evaluated, ultrasound showed sensitivity of 85.7% (95% confidence interval (CI): 69.7-95.2%) for occlusion and specificity of 99.5% (95%CI: 96.9-99.9%). Among 126 arteries without occlusion, <50% stenosis had average MFV (39±19 cm/s), 50-69% stenosis had average MFV (68±35 cm/s), and severe (70-99%) stenosis had average MFV (120±93 cm/s) (P<.001). MFV cutoff value of 44 cm/s corresponded to 77% sensitivity and 70% specificity to detect vertebral artery origin stenosis >50% (C-statistic: .81). PSV value of 97 cm/s corresponded with 72% sensitivity and 70% specificity to detect >50% stenosis (C-statistic: .77). MFV cutoff value of 60 cm/s corresponded with 70% sensitivity and 82% specificity to predict 70-99% stenosis (C-statistic: .83). PSV cutoff value of 110 cm/s corresponded with 80% sensitivity and 72% specificity to predict 70-99% stenosis (C-statistic: .84). Ultrasound has good sensitivity and excellent specificity for detecting vertebral origin occlusion. Flow velocity can be used to screen for severe stenosis of vertebral artery at origin.

Comparison of Supraceliac and Infrarenal Aortic Conduits in Liver Transplantation: Is There a Difference in Patency and Postoperative Renal Dysfunction?

Background.Aorto-hepatic conduits can provide arterial inflow for liver transplants in cases where the native hepatic artery is unsuitable for use.Methods.Clinical outcomes of all patients undergoing liver transplantation (LT) with an aorto-hepatic conduit between 2000 and 2016 were included. Recipients were divided into 2 groups: those with a supraceliac (SC) aortic conduit (N = 22) and those with an infrarenal (IR) aortic conduit (N = 82).Results.There was no difference in calculated model for end-stage liver disease score between the 2 groups. The SC group received grafts with a higher mean donor risk index (1.69 versus 1.48; P = 0.02). Early allograft dysfunction was 18.2% in the SC group and 29.3% in the IR group (P = 0.30). In the SC group, 10.5% of patients required initiation of postoperative continuous renal replacement therapy compared to 12.1% of patients in the IR group (P = 0.69). No difference in the rate of postoperative acute kidney injury was seen between the 2 groups (P = 0.54). No significant difference in median creatinine at 1 year was seen between the SC (1.2 mg/dL; IQR 1–1.3) and IR (1.2 mg/dL; IQR 0.9–1.5) groups (P = 0.85). At a median follow-up of 5.3 years, thrombosis of the aortic conduit occurred in 0% of patients in the SC group and 6.1% of patients in the IR group (P = 0.24). Graft survival was not significantly different between the 2 groups (P = 0.47).Conclusions.No difference in renal dysfunction as demonstrated by need for post-LT continuous renal replacement therapy, acute kidney injury, or creatinine at 1 year post-LT was seen between SC and IR aortic conduits. A slight trend of higher conduit thrombosis rate was seen with IR compared to SC aortic conduits; however, this did not reach statistical significance. Both SC and IR aortic conduits represent reasonable options when the native hepatic artery is unsuitable for use.

Long-term outcomes of percutaneous coronary intervention in grafts and native vessels in coronary artery bypass grafting patients with diabetes mellitus.

Atherosclerosis in diabetic patients progresses fast. Evidence on how to choose target vessels of percutaneous coronary interventions (PCIs) in diabetic patients post-coronary artery bypass graft (post-CABG) is insufficient. One hundred and fifty-seven patients with diabetes and previous CABG, who underwent PCI of either a graft vessel (GV) (n=44) or a native vessel (NV) (n=113) in the National Center for Cardiovascular Disease, China, were studied. In-hospital and long-term clinical outcomes were compared between the groups. Diabetic patients with prior CABG had more PCI to native arteries, but the proportion of grafts PCI increased as time went on. Both groups had similar baseline characteristics. Group GV patients compared with group NV had more totally occluded NVs, less totally occluded grafts and more in-stent restenosis. However, there was no difference in in-hospital mortality and long-term incidence of major adverse cardiac event (MACE), cardiac death, nonfatal myocardial infarction (MI), or revascularization. Multivariate logistic regression analysis showed that PCI success [hazard ratio (HR), 11.488; 95% confidence interval (CI), 1.135-116.303; P<0.05] was independent predictor of MACE. It suggested similar long-term clinical outcomes after PCI in GV or NV in prior CABG patients with diabetes. Thus, the vessel with higher estimated PCI success rate should be prioritized by operators.

Physico-mechanical and in vitro characterization of electrically conductive electrospun nanofibers of poly urethane/single walled carbon nano tube by great endothelial cells adhesion for vascular tissue engineering

Cardiovascular diseases (CVD) because of blood vessel disease are considered as one of the most frequent causes for mortality in all over the world. Recently, blood vessel tissue engineering is identified as one the promising strategies in order to overcome CVD. Accordingly, using Nano technology provides many benefits in blood vessel tissue engineering. In Present research Unique electrical, mechanical and biochemical properties of SWNT combined with electrospun polyurethane nanofiber was investigated as a functional composite scaffold for vascular tissue engineering. SWNT and polyurethane nanofibers incorporation indicated a biomechanical behavior similar to native artery. The scaffold morphological properties have been investigated by the use of scanning electron microscopy. With respect to the results, nanofiber diameter distribution was narrowed down by increasing SWNT content, while mean nanofiber diameter increased from 40 nm up to 140 nm. Physico-chemical characterization using FTIR, DSC, XRD and Raman test, demonstrated the nanoparticle appropriate dispersion and interaction to the polyurethane macromolecule. Along with increasing SWNT content up to the 2% (W/W) ultimate stress and young modulus increased 3 and 11 time, compared to pure PU, respectively. Structures electrical conductivity was increased from 0.0013 s/cm to 0.36 s/cm along with the increasing of SWNT content up to 2%. SWNT unique properties modulated samples hydrophilicity, and also contact angle of nanofiber scaffolds decreased from 1000 to 770. By passing 7 days, in vitro cell culture demonstrated dense layer of endothelial cells, which is crucial for blood vessel tissue engineering. Obtained results confirmed that electrospun poly urethane-SWNT scaffold could be considered as an appropriate candidate for blood vessel tissue engineering.

Use of Aligned Microscale Sacrificial Fibers in Creating Biomimetic, Anisotropic Poly(glycerol sebacate) Scaffolds.

Poly(glycerol sebacate) (PGS) is a biocompatible, biodegradable elastomer that has been shown promise as a scaffolding material for tissue engineering; it is still challenging, however, to produce anisotropic scaffolds by using a thermoset polymer, such as PGS. Previously, we have used aligned sacrificial poly(vinyl alcohol) (PVA) fibers to help produce an anisotropic PGS membrane; a composite membrane, formed by embedding aligned PVA fibers in PGS prepolymer, was subjected to curing and subsequent PVA removal, resulting in aligned grooves and cylindrical pores on the surface of and within the membrane, respectively. PVA, however, appeared to react with PGS during its curing, altering the mechanical characteristics of PGS. In this study, aligned sacrificial fibers made of polylactide (PLA) were used instead. Specifically, PLA was blend-electrospun with polyethylene oxide to increase the sacrificial fiber diameter, which in turn increased the size of the grooves and cylindrical pores. The resultant PGS membrane was shown to be in vitro cyto-compatible and mechanically anisotropic. The membrane’s Young’s modulus was 1–2 MPa, similar to many soft tissues. In particular, the microscale grooves on the membrane surface were found to be capable of directing cell alignment. Finally, based on the same approach, we fabricated a biomimetic, anisotropic, PGS tubular scaffold. The compliance of the tubular scaffold was comparable to native arteries and in the range of 2% to 8% per 100 mmHg, depending on the orientations of the sacrificial fibers. The anisotropic PGS tubular scaffolds can potentially be used in vascular tissue engineering.

Gelatin-polytrimethylene carbonate blend based electrospun tubular construct as a potential vascular biomaterial.

The present work details the fabrication of electrospun tubular scaffolds based on the biocompatible and unexploited blend of gelatin and polytrimethylene carbonate (PTMC) as a media (middle layer of blood vessel) equivalent for blood vessel regeneration. An attempt to resemble the media stimulated the selection of gelatin as a matrix (substitution for collagen) with the inclusion of the biodegradable elastomer PTMC (substitution for elastin). -The work highlights the variation of electrospinning parameters and its assiduous selection based on fiber diameter distribution and pore size distribution to obtain smooth microfibers and micropores which is reported for the first time for this blend. Electrospun conduits of gelatin-PTMC blend had fibers sized 6-8 μm and pores sized ~100-150 μm. Young's modulus of 0.40 ± 0.045 MPa was observed, resembling the tunica media of the native artery (~0.5 MPa). An evaluation of the surface properties, topography, and mechanical properties validated its physical requirements for inclusion in a vascular graft. Preliminary biological tests confirmed its minimal in-vitro toxicity and in-vivo biocompatibility. MTT assay (indirect) elucidated cell viability above 70% with scaffold extract, considered to be non-toxic according to the EN ISO-10993-5/12 protocol. The in-vivo subcutaneous implantation in rat showed a marked reduction in macrophages within 15 days revealing its biocompatibility and its possibility for host integration. This comprehensive study presents for the first time the potential of microporous electrospun gelatin and PTMC blend based tubular construct as a potential biomaterial for vascular tissue engineering. The proposed media equivalent included in a bilayer or trilayer polymeric construct can be a promising off-shelf vascular graft.

Temporal Trends and Management of Acute Aortic Occlusion: A 21 Year Experience

The aim was to study patients with acute aortic occlusion (AAO), a rare and life threatening event, in a population based cohort and the outcome of surgical treatment. The Swedish nationwide vascular database (Swedvasc) was used to identify cases, and the population registry to study long term survival. Variables associated with outcome were tested with the chi-square test and analysis of variance. During the 21 year study period (1994-2014), 693 cases of surgical treatment for AAO were included, with a yearly incidence of 3.6 per million inhabitants. Mean±SD age was 69.9±11.2 years, 352 patients (50.8%) were women, and mean±SD length of follow up was 5.2±5.5 years. Most patients presented with bilateral acute limb ischaemia (596 patients, 86.0%). The aetiology of AAO was native artery thrombosis in 458 patients (66.1%), saddle embolus in 152 (21.9%), and occluded graft/stent/stent grafts in 83 (12.0%). The proportion of occluded grafts/stent/stent grafts increased during the study period (n=14 [6.7%] in 1994-2000 vs. n=45 [17.4%] in 2008-2014; p<.001) with a simultaneous reduction of arterial thrombosis (n=149 [71.6%] in 1994-2000 vs. n=158 [61.2%] in 2008-2014; p <. 001). Major amputation above the ankle was performed in 39 patients (8.5%), and 140 patients died within 30 days of surgery (20.2%). Thirty day mortality rate was lower after occluded grafts/stents/stent grafts (eight patients [9.6%]) and higher after saddle embolus (47 patients [30.9%]); p<.001). There was a reduction in overall 30 day mortality over time (n=53 [25.5%] in 1994-2000 vs. n=40 [15.5%] in 2008-2014; p=.007). Long term survival revealed significant differences between the subgroups, although the difference occurred early after the event (p<.001). Mortality after surgical treatment of AAO is improving over time, yet a significant mortality rate was observed throughout the study period. The proportion of AAO secondary to occluded grafts/stents/stent grafts increased over time.

Prognostic risk factors for recurrent acute lower limb ischemia in patients treated with intra-arterial thrombolysis

ObjectiveThe objective of this study was to assess factors predisposing patients to recurrent acute lower limb ischemia (RALLI). MethodsAcute lower limb ischemia patients treated with catheter-directed thrombolysis (CDT) at Tampere University Hospital and Turku University Hospital between March 2002 and December 2015 were included. The patients' baseline demographics, comorbidities, and other characteristics were assessed retrospectively. Significant factors revealed by univariable analysis were tested in a multivariable model for associations with RALLI. A patency analysis was performed, and the risks of reocclusion were identified. The limb salvage rates after reocclusion were evaluated. ResultsAltogether, 303 consecutive patients with a mean age of 71 years (standard deviation, 11.8 years) were included. Of them, 159 (52.5%) were men. A total of 164 (54.1%) native arterial and 139 (45.9%) bypass graft occlusions were initially treated with CDT. On completion of CDT, 204 additional endovascular or conventional surgical procedures on 203 patients were performed to obtain adequate distal perfusion. During a median follow-up of 40 months (interquartile range, 69 months), 40 (24.4%) cases of RALLI occurred in native arteries and 90 (64.7%) in bypass graft patients (P < .001). In native arteries, the absence of appropriate anticoagulant and antiplatelet medication was independently associated with the development of acute reocclusions (hazard ratio, 6.51) in the Cox multivariable regression analysis. The patency rates were 86.6%, 72.2%, and 68.0% at 1 year, 5 years, and 9 years, respectively. In bypass grafts, worsened tibial runoff (crural index III: hazard ratio, 2.40) was independently associated with RALLI. The respective patency rates were 60.5%, 34.0%, and 29.2% for synthetic conduits and 30.8%, 20.5%, and 13.7% for autologous vein grafts at 1 year, 5 years, and 9 years. Altogether, 38 (29.2%) major amputations were performed on patients with reocclusions. Patients with synthetic conduits demonstrated superior limb salvage rates after reocclusion in comparison to native arteries or vein grafts (P = .025). ConclusionsAppropriate post-thrombolytic antiplatelet or anticoagulant treatment after native arterial events is of great importance, but additional data are needed to improve treatment algorithms. Adequate outflow in bypass graft patients is crucial. Patients with prosthetic bypass grafts have superior limb salvage rates after reocclusion.

Prosthetic Versus Native Artery Inflow for Infrainguinal Bypass

Abstract Background Infrainguinal bypass performed after previous prosthetic inflow reconstruction offers a choice of where to perform the proximal anastomosis. The hood of a previous inflow bypass might be technically easier to isolate during reoperative surgery. However, the more distal native artery might offer better patency to the outflow revascularization. The purpose of the present study was to compare the outcomes of infrainguinal bypass using the hood of a previous inflow bypass vs the native artery as the inflow source. Methods A single vascular group's database was queried for all cases of infrainguinal bypass performed after previous prosthetic inflow bypass to a femoral artery from January 2006 to December 2016. The demographics, indications, operative details, and long-term results were recorded and analyzed. Two groups were compared stratified by the location of the proximal anastomosis for the distal bypass. In one group, the inflow source for the distal bypass was from the hood of a previous inflow graft (prosthetic). In the second group, the distal native arterial tree was used as the inflow source. A subset analysis of the patency of the distal bypass was also performed between the two groups for those in which the previous inflow reconstruction had become occluded. Patency was calculated using the Kaplan-Meier method. Results A total of 197 patients had undergone infrainguinal bypass after previous inflow bypass from 2006 to 2016. Of the 197 procedures, 59 (30%) had used the hood of the previous bypass as the inflow source (prosthetic group) and 138 (70%) had used the native artery distal to the hood of the inflow bypass as the inflow source (native group). The indications were similar between the two groups. The two groups had a similar proportion of men and a similar incidence of hypertension, hyperlipidemia, coronary artery disease, tobacco use, and renal disease. The previous inflow procedures were also similar between the two groups. The native artery used for the inflow source in the native group was the profunda femoris in 80 (58%), common femoral artery in 51 (37%), and superficial femoral artery in 7 (5.1%). Patency was significantly greater for the native group at 1 year (91% vs 75%; P = .0221). Also, the patency after inflow bypass occlusion significantly favored the native group at 1 year (87% vs 40%; P = .0035). Conclusion Infrainguinal bypass performed after previous ipsilateral inflow bypass offers the option of using the hood of the bypass or a native artery as the inflow source. The present study demonstrated greater patency rates when using the distal native artery as the inflow source. The native artery option also offered continued patency when the inflow bypass occluded.

Abstract 755: Fas Ligand- and Nitric Oxide-Releasing Stent

To restore blood flow in stenotic vessels such as coronary arteries, metallic vascular stents are often used. However, stent deployment under high pressure leads to vascular wall and smooth muscle (SMC) damage, with compensatory thrombosis, inflammation, and neointimal proliferation of SMCs. These events result in vessel re-occlusion and treatment failure. In an effort to prevent intimal hyperplasia and treatment failure, drug-eluting stents were developed roughly 15 years ago. These stents release global inhibitors of proliferation (eg. “mTOR inhibitors”) which stop the growth of SMC as well as vascular endothelial cells (EC). Despite being widely used, drug-eluting stents mandate long-term treatment with potent anticoagulants. This is because mTOR inhibitors prevent re-endothelialization of the stent surface, leaving the clot-inducing metal exposed to the bloodstream. Yet, long-term dual antiplatelet therapy leads to increased risk of bleeding/stroke and myocardial infarction. Here, we leveraged the fact that nitric oxide (NO) increases Fas receptors on the SMC surface. Fas forms a death-inducing complex upon binding to Fas ligand (FasL), while ECs are relatively resistant to this pathway (Figure 1). Selected doses of FasL and NO donor synergistically increased SMC apoptosis and inhibited SMC growth more potently than did everolimus or sirolimus, while having no significant effect on EC viability and proliferation. We verified this differential effect in an ex vivo pig coronary artery model, where the intimal thickening was inhibited by the drug combination, but endothelial viability was retained. We also deployed FasL and NO donor-releasing ethylene-vinyl acetate copolymer (EVAc)-coated stents into pig coronary arteries, and cultured them in perfusion bioreactors for one week. FasL and NO donor, released from the stent coating, killed SMCs in the proximity of the stent struts, even in the presence of flow rates mimicking those of native arteries. Therefore, the FasL-NO donor-combination has the potential to prevent intimal hyperplasia and in-stent restenosis, without harming endothelial restoration, and hence may be a superior drug delivery strategy for drug-eluting stents.

Soft-sheath, stiff-core microfiber hydrogel for coating vascular implants

Vascular implants remain clinically challenged due to often-occurring thrombosis and stenosis. Critical to addressing these complications is the design of implant material surfaces to inhibit the activities of platelets, smooth muscle cells (SMCs) and inflammatory cells. Recent mechanobiology studies accentuate the significance of material elasticity to cells and tissues. We thus developed and characterized an implant coating composed of hybrid, viscoelastic microfibers with coaxial core-sheath nanostructure. The coating over metallic stent material was formed by first depositing coaxially-electrospun fibers of poly(L-lactic acid) core and polyethylene glycol dimethacrylate sheath, and then polymerizing fibers with various UV times. Material characterizations were performed to evaluate the coating structure, mechanical property and biocompatibility. Results showed that coaxial microfibers exhibited arterial-like mechanics. The soft surface, high water content and swelling ratio of the coaxial fibers resemble hydrogels, while they are mechanically strong with an elastic modulus of 172–729 kPa. The coating strength and surface elasticity were tunable with the photopolymerization time. Further, the elastic fibers, as conformal coating on stent metal, strongly reduced SMC overgrowth and discouraged platelet adhesion and activation, compared to bare metals. Importantly, after 7-day subcutaneous implantation, coaxial fiber-coated implants showed more favorable in vivo responses with reduced tissue encapsulation, compared to bare stent metals or those coated with a two-layered fiber mixture composed of fibers from individual polymers. The excellent biocompatibility aroused from nanostructural interfaces of hybrid fibers offering hydrated, soft, nonfouling microenvironments. Such integrated fiber system may allow creation of advanced vascular implants that possess physico-mechanical properties of native arteries.

Rapid fabrication of reinforced and cell-laden vascular grafts structurally inspired by human coronary arteries

Design strategies for small diameter vascular grafts are converging toward native-inspired tissue engineered grafts. A new automated technology is presented that combines a dip-spinning methodology for depositioning concentric cell-laden hydrogel layers, with an adapted solution blow spinning (SBS) device for intercalated placement of aligned reinforcement nanofibres. This additive manufacture approach allows the assembly of bio-inspired structural configurations of concentric cell patterns with fibres at specific angles and wavy arrangements. The middle and outer layers were tuned to structurally mimic the media and adventitia layers of native arteries, enabling the fabrication of small bore grafts that exhibit the J-shape mechanical response and compliance of human coronary arteries. This scalable automated system can fabricate cellularized multilayer grafts within 30 min. Grafts were evaluated by hemocompatibility studies and a preliminary in vivo carotid rabbit model. The dip-spinning-SBS technology generates constructs with native mechanical properties and cell-derived biological activities, critical for clinical bypass applications.

One-Year Late Lumen Loss between A Polymer-Coated Paclitaxel-Eluting Stent (Eluvia) and a Polymer-Free Paclitaxel-Coated Stent (Zilver PTX) for Femoropopliteal Disease

Aim: Paclitaxel-eluting stents' (Eluvia and Zilver PTX) effectiveness has been recently reported for femoropopliteeal (FP) lesions. However, there is no evaluation of one-year late lumen loss (LLL). Therefore, we evaluated one-year LLL after implantation with Eluvia or Zilver PTX.Methods: This was a multicenter, prospective study. Patients who had symptomatic de novo lesions in the native FP artery were enrolled. The primary endpoint was one-year angiographic LLL, and the secondary endpoints were binary restenosis and target lesion revascularization (TLR) at one year.Results: From December 2015 to December 2016, 48 patients (Eluvia, 36 patients; Zilver PTX, 12 patients) were enrolled. No significant difference was found in baseline and lesion characteristics between both groups. One-year, LLL was significantly lower in the Eluvia group (0.60 {plus minus}0.80 mm) than in the Zilver PTX group (1.74 {plus minus}0.89 mm) (P = 0.0003). Negative LLL was observed only in the Eluvia group (0% vs. 23%, p = 0.096). The binary restenosis rate was significantly lower than in the Zilver PTX group (0% vs. 16.7%, P = 0.012). The one-year TLR in the Eluvia group tended to be lower (0% vs. 8.3%, P = 0.08). Stent thrombosis was not observed in either group.Conclusion: One-year LLL in the Eluvia group was significantly lower than that in the Zilver PTX group for FP lesions.

IN.PACT SFA Clinical Study Using the IN.PACT Admiral Drug-Coated Balloon in a Chinese Patient Population

Purpose: To confirm the safety and effectiveness of the IN.PACT Admiral drug-coated balloon (DCB) as a treatment for de novo and native artery restenotic lesions in the superficial femoral artery (SFA) and/or proximal popliteal artery in Chinese subjects. Materials and Methods: IN.PACT SFA China (ClinicalTrials.gov identifier NCT02118532) was a single-arm, independently adjudicated, prospective, premarket study that enrolled 143 subjects (mean age 66.8±7.7 years; 107 men) at 15 centers. The predominant risk factors were hypertension (104, 72.7%) and diabetes mellitus (66, 46.2%). The majority of subjects were classified as Rutherford category 2 or 3 [69 (48.3%) and 55 (38.5%), respectively]; 19 (13.3%) subjects had critical limb ischemia (Rutherford category 4). The mean lesion length was 10.4±6.51 cm; more than half of the lesions (75, 52.4%) were chronic total occlusions. Calcification was found in 66 (46.2%) lesions. Outcomes at 12 months were compared with DCB safety and effectiveness performance goals derived from the literature. The 30-day primary safety outcome was a composite of freedom from device- and procedure-related mortality, major target limb amputation, and clinically-driven target lesion revascularization (CD-TLR). Results: The primary safety outcome was 99.3% at 30 days. Follow-up compliance at 12 months was 92.6%. Estimated 1-year primary patency using Kaplan-Meier analysis was 90.9% and freedom from CD-TLR was 97.1%. The rate of CD-TLR at 12 months was 2.9%. The Rutherford category status improved significantly (p<0.001) between baseline and 12 months. Conclusion: Results from IN.PACT SFA China demonstrated high rates of patency and low rates of CD-TLR in Chinese subjects through 12 months despite patient and lesion complexity. These data are consistent with the results of other IN.PACT DCB trials.

PC024. Lower Limb Malperfusion in Acute Type A Dissection

Acute type A aortic dissection (ATAD) presenting with acute limb ischemia (ALI) has been identified as a predictor of in-hospital mortality. This study examines the outcome of patients presenting with ATAD with ALI. A prospectively collected database was queried for all cases of ATAD repaired between 2002 and 2018 at a tertiary referral center. Patients presenting with ALI were identified. Comparisons between groups with and without lower extremity ALI were made. For continuous variables, univariate two-group comparisons were performed. For categorical variables, univariate two-group comparisons are performed. Statistical significance is set at P < .05. During this period, 378 patients (average age, 56.9 years) underwent ATAD repair. Of these, 62 patients (16.4%) presented with ALI; 35 patients (9.2%) presented with isolated ALI, whereas 27 (7.1%) had concomitant malperfusion in at least one other organ system. Of the 62 patients presenting with ALI, 46 (74.2%) underwent proximal aortic repair alone; 16 (25.8%) also underwent lower extremity vascular intervention (Fig). In the latter part of the study, perfusion of the ischemic limb was accomplished during repair of the ATAD through a side perfusion cannula directly from the bypass circuit (10 patients). There were six amputations (9.7%) performed in the ALI group, two of which had peripheral vascular repairs. Fasciotomies were performed on 18 patients; of these, 5 had concomitant peripheral vascular repairs. Of the 55 patients with ALI surviving past 24 hours, 34 (61%) had resolution of their lower limb ischemia with proximal repair only. The 30-day survival was decreased in patients who presented with any organ malperfusion (P = .012). However, in patients with isolated ALI, there was no significant difference in 30-day mortality (11.4%) compared with the group with no malperfusion (15.7%; P = .5). Sixteen patients underwent peripheral vascular procedures for their limb ischemia, including 10 patients who underwent bypass procedures (7 femoral-femoral, 1 axillary-femoral-femoral, and 2 axillary-femoral), with 1 patient dying within 24 hours. All six patients with adequate follow-up imaging demonstrated asymptomatic occlusion of the bypass graft. In this group, computed tomography angiography showed recanalization of the occluded native arteries. Proximal repair of ATAD resolves most associated ALI. Isolated ALI did not increase 30-day mortality. All patients with follow-up who underwent extra-anatomic bypass developed asymptomatic graft occlusion. This was attributed to competitive flow from the remodeled native arterial system.

IP225. Real-World Outcomes of EKOS Ultrasound-Enhanced Catheter-Directed Thrombolysis for Acute Limb Ischemia

Ultrasound-enhanced catheter-directed thrombolysis (UET) using the EKOS device (EKOS Corporation, Bothell, Wash) for acute peripheral artery ischemia has been purported in clinical trials to accelerate the fibrinolytic process to reduce treatment time and lytic dosage. However, UET performance in a real-world clinical setting has thus far been inadequately described. We performed a retrospective review of all patients undergoing UET for acute limb ischemia at a single institution during a 5-year period. Data collected included patients' demographics, procedural details, and 30-day and 1-year outcomes. Primary outcomes were major bleeding events, limb salvage, and mortality. We identified 32 patients (mean age, 67.4 ± 14.9 years; 25% female) who underwent UET for acute limb ischemia between 2014 and 2018. At presentation, 43.8% were therapeutically anticoagulated. Rutherford acute limb ischemia classification was I in 56.3%, IIa in 25.0%, and IIb in 18.8%. Etiology was thrombosis of native artery in 12.5% of patients, infrainguinal prosthetic bypass in 31.3%, infrainguinal autogenous bypass in 6.3%, and stented native vessel in 50.0%. Mean duration of thrombolytic therapy was 22.2 ± 11.3 hours, and mean tissue plasminogen activator dose was 24.5 ± 15.3 mg. In-line flow to the foot was re-established in 90.6% of patients with a significant improvement in preoperative to postoperative ankle-brachial index (0.31 ± 0.29 vs 0.78 ± 0.34; P < .001) and number of patent tibial runoff vessels (1.31 ± 1.20 vs 1.96 ± 0.86; P < .001; Fig). There was no significant difference in revascularization success between occluded vessel types: native vessel, 75% success; stented vessel, 93.8%, autogenous bypass, 100%, and prosthetic bypass, 90% (P = .48). Major bleeding complications occurred in three patients (9.4%), including two intracranial hemorrhages (6.3%). Limb salvage at 30 days and 1 year was 93.8% and 87.5%, respectively. Ipsilateral reintervention was required in 37.5% of patients within 1 year. Overall mortality was 6.2% at 30 days and 13.5% at 1 year, and mortality was significantly higher in patients with higher Rutherford class (P = .049). UET with the EKOS device demonstrates acceptable real-world outcomes in the treatment of acute limb ischemia. UET is generally safe, with a low rate of associated hemorrhagic complications, and is effective at re-establishing in-line flow to yield high limb salvage rates. However, UET is associated with a high rate of reintervention within 1 year. Further investigation is needed into specific predictors of limb salvage and need for reintervention as well as cost-efficacy of this technology compared with traditional methods.