Small Stents Research Articles

Inverse design of deployable origami structures that approximate a general surface

Shape-morphing finds widespread utility, from the deployment of small stents and large solar sails to actuation and propulsion in soft robotics. Origami structures provide a template for shape-morphing, but rules for designing and folding the structures are challenging to integrate into broad and versatile design tools. Here, we develop a sequential two-stage optimization framework to approximate a general surface by a deployable origami structure. The optimization is performed over the space of all possible rigidly and flat-foldable quadrilateral mesh origami. So, the origami structures produced by our framework come with desirable engineering properties: they can be easily manufactured on a flat reference sheet, deployed to their target state by a controlled folding motion, then to a compact folded state in applications involving storage and portability. The attainable surfaces demonstrated include those with modest but diverse curvatures and unprecedented ones with sharp ridges. The framework provides not only a tool to design various deployable and retractable surfaces in engineering and architecture, but also a route to optimizing other properties and functionality.

Technical Feasibility and Histological Analysis of Balloon-Expandable Metallic Stent Placement in a Porcine Eustachian Tube

There is a clinical need to develop a stent to treat obstructive and refractory Eustachian tube dysfunction (ETD) after balloon Eustachian tuboplasty. An animal model for stent placement in the Eustachian tube (ET) is needed to develop optimal designs and materials, as stents for ETD have not been clinically applied. The purpose of this study was to evaluate the technical feasibility of stent placement and histological changes in a porcine ET model. Six ETs were evaluated in three pigs. Cobalt–chrome alloy stents with two different diameters were placed in the left and right ET of each animal (right, 3.5 mm; left, 2.5 mm). The outcomes were assessed by endoscopic and fluoroscopic imaging during the procedure, computed tomography after the procedure, and by histological examinations. Stent placement was technically successful in all specimens after metallic guiding sheaths were located in the nasopharyngeal end of the ET. The mean luminal diameters of the proximal, middle, and distal portions of the larger stents in the right ETs were 3.48 mm, 2.54 mm, and 2.15 mm, respectively. In the left ETs using smaller stents, these values were 2.49 mm, 1.73 mm, and 1.42 mm, respectively. The diameters of the inserted stents differed by stent location and the original diameter. Histological findings showed tissue hyperplasia with severe inflammatory cell infiltration at 4 weeks after stent placement. In conclusion, stent placement into the porcine ET was technically feasible, and stent-induced tissue hyperplasia was significantly evident. The luminal configuration of the placed ET stent changed according to its non-elastic nature and anatomical features of the porcine ET. Using this model, ET stents of various materials and designs with anti-inflammatory or anti-proliferative drugs can be optimized for future treatments of ET dysfunction.

Tracheocutaneous Fistula After Pediatric Open Airway Reconstruction.

Tracheocutaneous fistula (TCF) is a common occurrence after pediatric tracheostomy decannulation. However, the persistence of TCF after staged reconstruction of the pediatric airway is not well-described. The primary objective was to determine the rate of persistent TCF after successful decannulation in children with staged open airway reconstruction. A case series with chart review of children who underwent decannulation after double-stage laryngotracheal reconstruction between 2017 and 2019. A total of 26 children were included. The most common open airway procedure was anterior and posterior costal cartilage grafting (84.6%, 22/26). Median age at decannulation was 3.4 years (IQR: 2.8-4.3) and occurred 7.0 months (IQR: 4.3-10.4) after airway reconstruction. TCF persisted in 84.6% (22/26) of children while 15.4% (4/26) of stomas closed spontaneously. All closures were identified by the one-month follow-up visit. There was no difference in age at tracheostomy (P = .86), age at decannulation (P = .97), duration of tracheostomy (P = .43), or gestational age (P = .23) between stomas that persisted or closed. Median diameter of stent used at reconstruction was larger in TCFs that persisted (7.0 mm vs 6.5 mm, P = .03). Tracheostomy tube diameter (P = .02) and stent size (P < .01) correlated with persistence of TCF on multivariable logistic regression analysis. There were 16 surgical closure procedures, which occurred at a median of 14.4 months (IQR: 11.4-15.4) after decannulation. Techniques included 56.3% (9/16) by primary closure, 18.8% (3/16) by secondary intention and 25% (4/16) by cartilage tracheoplasty. The overall success of closure was 93.8% (15/16) at latest follow-up. Persistent TCF occurs in 85% of children who are successfully decannulated after staged open airway reconstruction. Spontaneous closure could be identified by 1 month after decannulation and was more likely when smaller stents and tracheostomy tubes were utilized. Surgeons should counsel families on the frequency of TCF and the potential for additional procedures needed for closure.

Colon Ascendens Stent Peritonitis (CASP ).

Colon ascendens stent peritonitis (CASP) is one of the well-established models of experimental abdominal sepsis. In CASP surgery, an open link between the gut lumen and the abdominal cavity is created by placing a stent into the colon ascendens. This mimics well the insufficient intestinal anastomosis. It causes a continuous leakage of the gut contents into the peritoneum and leads therefore to peritonitis and sepsis. The abdominal cavity is opened under general anesthesia and a plastic stent is located through and sutured to the colonic wall. The septic severity in CASP models can be titrated by altering the size of the stent catheter. Therefore, CASP models with small stents sizes are suitable for long-term studies and studies with mild/moderate sepsis severity. Within 24h, animals develop clinical signs of sepsis. Monitoring of the clinical state, sufficient analgesia, appropriate antibiotics and fluid resuscitation should be performed postoperatively.

Abstract 16295: Smaller Stent Area and Eccentric Expansion are Associated With Increased Adverse Events After Drug-eluting Stent Implantation in Hemodialysis Patients

Introduction: Factors for adverse cardiac events after drug-eluting stent (DES) implantation among patients with hemodialysis (HD) remain to be elucidated. Hypothesis: Suboptimal DES implantation is associated with the increased incidence of adverse events in patients with HD. Methods: A total of 109 consecutive patients with HD who underwent optical coherence tomography (OCT)-guided DES implantation were included. The impact of post-stent OCT findings on the incidence of device-oriented clinical endpoints (DoCE) at 1 year was investigated. DoCE included cardiac death, target vessel-related myocardial infarction, target lesion revascularization, and stent thrombosis. Results: There was no significant difference in baseline clinical characteristics and pre-stent lesion characteristics between patients with DoCE (n=15) and those without DoCE (n=94). Significant hazard ratio (HR) for the incidence of DoCE was not observed in the presence of edge dissection, irregular protrusion, or incomplete stent apposition (Panel A). In receiver operating characteristic curve analyses, the best cutoff of minimum stent cross-sectional area (MSA), %stent expansion [MSA / mean reference lumen cross-sectional area х 100], and eccentricity index (minimum stent diameter / maximum stent diameter) at MSA site for detecting DoCE was 3.4 (mm 2 ), 72.0 (%), and 0.71, respectively. Significant HR for the incidence of DoCE was observed in the presence of MSA&lt; 3.4 (HR 3.58, 95% confidence interval [CI] 1.04 - 12.4, p=0.035) and eccentricity index&lt; 0.71 (HR 6.68, 95% CI 1.94 - 23.0, p=0.001) (Panel B). Conclusions: Smaller stent area and eccentric expansion were associated with increased incidence of DoCE after DES implantation in patient with HD, although the presence of other post-stent suboptimal findings were not associated with the incidence of DoCE. The present results suggest the importance of larger stent area and concentric stent expansion in patients with HD.

Clinical impact of angiographically insignificant suboptimal poststent findings detected by optical coherence tomography after drug-eluting stent implantation.

Although optical coherence tomography (OCT)-detected suboptimal findings (SF-OCT) such as malapposition, edge dissection, tissue protrusion, thrombus and small minimal stent area (MSA) are frequently observed after the implantation of drug-eluting stents (DES), their clinical implications are controversial. Clinical outcomes may differ between patients with SF-OCTs and without SF-OCTs after DES implantation. A total of 576 patients undergoing OCT analysis after DES implantation were divided into SF-OCT group (n = 379, 379 lesions) and No SF-OCT group (n = 197, 197 lesions). The study population had no significant abnormal finding in final angiography. Quantification was performed for each SF-OCT. The incidences of major adverse cardiovascular events (MACE: all-cause death, non-fatal myocardial infarction, target vessel revascularization, and stent thrombosis) were compared between the two groups. A median follow-up duration was 21.5 months. Among 379 patients with SF-OCT, 32.4% had multiple SF-OCTs. Malapposition (32.1%, IQR of maximal depth 315-580 μm) was the most frequent, followed by small MSA (31.6%), edge dissection (12.5%, IQR of maximal flap of opening 0.27-0.52 mm), thrombus (7.6%, IQR of diameter 1.31-1.97mm) and tissue protrusion (6.8%, IQR of diameter 1.05-1.67 mm). The SF-OCT group showed smaller stent diameter and longer stent length, and lower in-stent lumen expansion rate. The incidence of MACE did not differ between the two groups (3.0% for No SF-OCT vs. 5.0% for SF-OCT; HR 1.601; 95% CI 0.639 to 4.011; P = 0.310). The presence of angiographically insignificant SF-OCTs were not associated with clinical outcomes in this study.

Transjugular Intrahepatic Portosystemic Shunt Placement for Portal Hypertension: Meta-Analysis of Safety and Efficacy of 8 mm vs. 10 mm Stents.

Introduction Hepatic encephalopathy (HE) following transjugular intrahepatic portosystemic shunt (TIPS) placement remains a leading adverse event. Controversy remains regarding the optimal stent diameter given that smaller stents may decrease the amount of shunted blood and decrease the risk of HE, but stent patency and/or clinical adequacy of portal decompression may also be affected. We aim to provide meta-analysis-based evidence regarding the safety and efficacy of 8 mm vs. 10 mm stents during TIPS placement. Methods PubMed, Embase, Cochrane Library, and Web of Science were searched for studies comparing 8 mm and 10 mm stents during TIPS placement for portal hypertension decompression in cirrhotic patients. Randomized controlled trials and cohort studies were prioritized for inclusion. Overall evaluation of quality and bias for each study was performed. The outcomes assessed were the prevalence of HE, rebleeding or failure to control refractory ascites, and overall survival. Subgroup analysis based on TIPS indication was conducted. Results Five studies with a total number of 489 cirrhotic patients were identified. The pooled hazard ratio (HR) of post-TIPS HE was significantly lower in patients in the 8 mm stent group than in the 10 mm stent group (HR: 0.68, 95% CI: 0.51~0.92, p value < 0.0001). The combined HR of post-TIPS rebleeding/the need for paracentesis was significantly higher in patients in the 8 mm stent group than in the 10 mm stent group (HR: 1.76, 95% CI: 1.22~2.55, p value < 0.0001). There was no statistically significant difference in the overall survival between the 8 mm and 10 mm stent groups. The combined risk of HE in the variceal bleeding subgroup was statistically lower (HR: 0.52, CI: 0.34-0.80) with an 8 mm stent compared with a 10 mm stent. The combined risk of both rebleeding/paracentesis and survival was not statistically significant between 8 mm and 10 mm stent use in subgroup analysis. Conclusion 8 mm stents during TIPS placement are associated with a significant lower risk of HE compared to 10 mm stents (32% decreased risk), as well as a 76% increased risk of rebleeding/paracentesis. Meta-analysis results suggest that there is not one superior stent choice for all clinical scenarios and that the TIPS indication of variceal bleeding or refractory ascites might have different appropriate selection of the shunt diameter.

Thrombolysis in Cerebral Infarction 2b Reperfusions: To Treat or to Stop?

In patients undergoing mechanical thrombectomy, achieving complete (Thrombolysis in Cerebral Infarction 3) rather than incomplete successful reperfusion (Thrombolysis in Cerebral Infarction 2b) is associated with better functional outcome. Despite technical improvements, incomplete reperfusion remains the final angiographic result in 40% of patients according to recent trials. As most incomplete reperfusions are caused by distal vessel occlusions, they are potentially amenable to rescue strategies. While observational data suggest a net benefit of up to 20% in functional independence of incomplete versus complete reperfusions, the net benefit of secondary improvement from Thrombolysis in Cerebral Infarction 2b to 3 reperfusion might differ due to lengthier procedures and delayed reperfusion. Current strategies to tackle distal vessel occlusions consist of distal (microcatheter) aspiration, small adjustable stent retrievers, and administration of intra-arterial thrombolytics. While there are promising reports evaluating those techniques, all available studies show relevant limitations in terms of selection bias, single-center design, or nonconsecutive patient inclusion. Besides an assessment of risks associated with rescue maneuvers, we advocate that the decision-making process should also include a consideration of potential outcomes if complete reperfusion would successfully be achieved. These include (1) a futile angiographic improvement (hypoperfused territory is already infarcted), (2) an unnecessary angiographic improvement (the patient would not have developed infarction if no rescue maneuver was performed), and (3) a successful rescue maneuver with clinical benefit. Currently there is paucity of data on how these scenarios can be predicted and the decision whether to treat or to stop in a patient with incomplete reperfusion involves many unknowns. To advance the status quo, we outline current knowledge gaps and avenues of potential research regarding this clinically important question.

Is transradial access the way to go to prevent post PCI readmission?

Small vessel diameter is associated with higher risk of target lesion revascularization (TLR) after percutaneous coronary intervention (PCI). The COMBO sirolimus-eluting biodegradable-polymer stent has a proprietary anti-CD34 antibody layer to enhance homogeneous endothelialization, which may be advantageous in treating small vessels.We examined for differences in 1-year clinical outcomes after PCI by maximum implanted stent diameter from the COMBO collaboration.The COMBO collaboration (n = 3614) is a patient-level pooled dataset of patients undergoing PCI with COMBO stents in the MASCOT and REMEDEE multicenter registries. Stent diameter was available in 3590 (99.3%) patients. We compared patients receiving COMBO stents <3 mm versus ≥3 mm. The primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, target vessel-myocardial infarction (TV-MI) or clinically driven TLR. Secondary outcomes included stent thrombosis (ST). Adjusted outcomes were assessed using Cox regression methods.The study included 792 (22%) patients with small stents <3 mm and 2798 (78%) patients with large stents ≥3 mm. Small stent patients included more women with lower body mass index and higher prevalence of diabetes but similar prevalence of acute coronary syndrome. Risk of 1-year TLF was similar in small and large stent groups (4.4% vs. 3.8%, HR 1.12, 95% CI 0.74–1.72, p = 0.58). There were no differences in the rates of cardiac death (1.7% vs. 1.5%, p = 0.74), TV-MI (1.4% vs. 1.2%, p = 0.58) or TLR (2.7% vs. 2.1%, p = 0.31). Definite or probable ST occurred in 1.3% of the small stent and 0.7% of the large stent PCI patients, p = 0.14, HR 2.13, 95% CI 0.93–5.00, p = 0.07.One-year ischemic outcomes after COMBO PCI were similar irrespective of stent diameter in this all-comers international cohort.

Removal of covered metallic stents with a bullet head for bronchopleural fistula using a fluoroscopy-assisted interventional technique

To investigate the feasibility and safety of a fluoroscopy-assisted interventional technique for removal of bullet-shaped self-expanding covered metallic stents from bronchopleural fistulas (BPFs). Clinical data for 49 consecutive patients who underwent removal of bullet-shaped self-expanding covered metal stents from October 2010 to November 2019 were analysed retrospectively. Fifty-one stents were removed in all, including 29 large Y-shaped bullet stents, 10 small Y-shaped bullet stents, and 12 branched bullet-shaped stents. The average duration for which tracheal stents were in place was 99.4±8.5 days. Fifty-one stents were removed successfully, of which 49 were directly removed on the first attempt. The time required for stent removal ranged from 7-60 minutes (median time, 22 minutes). In eight cases, the stent was removed by the conventional method (i.e., grasping the upper tip of the stent to collapse and adduct the proximal end), and in 43 by the eversion method (i.e., grasping the distal end of the stent to invert and peel out). Interventional radiology is a simple, safe, and effective method to extract self-expanding covered metallic bullet-shaped stents, with no need for general anaesthesia and tracheal intubation. It has a short operation time, is well tolerated by patients, and is worthy of clinical application.

Extrabiliary applications of fully covered antimigration biliary metal stents.

Background and AimsEndoscopic stent placement in luminal GI strictures is not always feasible with traditional stents. For example, standard luminal stent delivery catheters may not successfully traverse severe strictures, and enteral stents may not be suitable for sites in the GI tract that pose significant adverse events if downstream migration were to occur. We demonstrate extrabiliary applications of specialized, fully covered antimigration biliary metal stents.MethodsThis is a retrospective series of 4 patients with different benign and malignant luminal GI strictures who underwent placement of fully covered antimigration biliary metal stents in different configurations as a bridge or destination therapy.ResultsLuminal obstruction resolved without adverse events in all cases.ConclusionsAlthough off label, extrabiliary use of these stents can successfully address scenarios of complex luminal pathology. To compensate for the small stent caliber, two stents may be placed side by side in a double-barrel configuration. Strict diet modifications are necessary when applying this therapeutic paradigm.

1-Year Outcomes with COMBO Stents in Small-Vessel Coronary Disease: Subgroup Analysis From the COMBO Collaboration

BackgroundSmall vessel diameter is associated with higher risk of target lesion revascularization (TLR) after percutaneous coronary intervention (PCI). The COMBO sirolimus-eluting biodegradable-polymer stent has a proprietary anti-CD34 antibody layer to enhance homogeneous endothelialization, which may be advantageous in treating small vessels. ObjectiveWe examined for differences in 1-year clinical outcomes after PCI by maximum implanted stent diameter from the COMBO collaboration. MethodsThe COMBO collaboration (n = 3614) is a patient-level pooled dataset of patients undergoing PCI with COMBO stents in the MASCOT and REMEDEE multicenter registries. Stent diameter was available in 3590 (99.3%) patients. We compared patients receiving COMBO stents <3 mm versus ≥3 mm. The primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, target vessel-myocardial infarction (TV-MI) or clinically driven TLR. Secondary outcomes included stent thrombosis (ST). Adjusted outcomes were assessed using Cox regression methods. ResultsThe study included 792 (22%) patients with small stents <3 mm and 2798 (78%) patients with large stents ≥3 mm. Small stent patients included more women with lower body mass index and higher prevalence of diabetes but similar prevalence of acute coronary syndrome. Risk of 1-year TLF was similar in small and large stent groups (4.4% vs. 3.8%, HR 1.12, 95% CI 0.74–1.72, p = 0.58). There were no differences in the rates of cardiac death (1.7% vs. 1.5%, p = 0.74), TV-MI (1.4% vs. 1.2%, p = 0.58) or TLR (2.7% vs. 2.1%, p = 0.31). Definite or probable ST occurred in 1.3% of the small stent and 0.7% of the large stent PCI patients, p = 0.14, HR 2.13, 95% CI 0.93–5.00, p = 0.07. ConclusionsOne-year ischemic outcomes after COMBO PCI were similar irrespective of stent diameter in this all-comers international cohort.

The Hemodynamic Impact of Mitral Regurgitation on Aortic Insufficiency in the LVAD-Supported Heart

Aortic valve incompetence (AI) is a serious complication that develops in 20% of LVAD patients within 12 months of implantation. Many LVAD patients with AI also develop mitral regurgitation (MR). Our goal in this study was to measure systemic flow (Qsys) and LVAD flow (QLVAD) during AI, MR and AI+MR. A mock circulatory loop with a dilated silicone LV and bioprosthetic valves was attached to a HeartMate II LVAD (Abbott Labs), and pressure and flow measured in the LV, LVAD and aorta. A Pre-LVAD ejection fraction of 20% without any valve dysfunction was established, followed LVAD support at speeds of 8, 9.4 and 11krpm. AI and MR were created with small stents that were non-obstructive to forward flow but prevented the leaflets from fully closing. Four conditions were tested: Normal, AI, MR and AI and MR combined. Average flow was obtained from ten cycles of data, and Q calculated as QLVAD/Qsys. Pre-LVAD AI, MR and AI+MR produced a 28%, 12% and 45% reduction in Qsys, respectively. LVAD support at 9.4krpm increased Normal Qsys to 3.6 L/min with 95% of flow through the LVAD. MR reduced Qsys by 16% and QLVADby 21%; AI reduced by Qsys by 24% but QLVADby only 5%; and AI+MR reduced Qsys by 25% and QLVADby 7%, which was comparable to AI alone. In all conditions except AI+MR, Q increases with LVAD speed indicating that QLVAD increases faster than Qsys. This trend reverses when MR is present, reducing the impact of AI as LVAD speed is increased. The major finding of these studies is that MR does not worsen Qsys when it coincides with AI and LVAD support. AI and MR occur during different phases of the cardiac cycle and sum in the absence of LVAD support. When an LVAD is added without valve dysfunction, QLVADis evenly distributed across systole and diastole. AI and MR reduces systolic and increases diastolic QLVAD, but AI+MR restores the original distribution. AI+MR produces the same overall Qsys but QLVADoccurs more evenly throughout the cardiac cycle resulting in a greater sensitivity to LVAD speed changes.

Geometric and hemodynamic analysis of fenestrated and multibranched aortic endografts

ObjectiveThe objective of this study was to determine the influence of hemodynamic force on the development of type III endoleak and branch thrombosis after complex endovascular thoracoabdominal aortic aneurysm repair. MethodsPatients with thoracoabdominal aortic aneurysm, within surgical range, treated with a fenestrated or branched endovascular aneurysm repair from 2014 to 2018 and with 3-month control computed tomography angiography were selected. Demographic variables, aneurysm anatomy, and endograft conformation were analyzed retrospectively from a prospective registry. The hemodynamic force was calculated using the mass and momentum conservation equations. ResultsTwenty-eight patients were included; the mean follow-up period was 24.7 ± 19.3 months. There were 102 abdominal vessels successfully catheterized (19 celiac arteries, 29 superior mesenteric arteries, 27 right renal arteries, 26 left renal arteries, and 1 polar renal artery). The rate of type III endoleak was 11.5% (n = 12); six cases were associated with branches that received two stents (P < .001). A higher rate of endoleak was observed with wider stents (8.50 ± 1.0 mm vs 7.17 ± 1.3 mm; P = .001) but not with longer stents (P = .530). All cases of type III endoleak affected visceral arteries (eight celiac arteries and four superior mesenteric arteries). The freedom from type III endoleak at 24 months was 86%. The rate of thrombosis was 5.9% (n = 6). A higher rate of thrombosis was observed in smaller vessels (5.00 ± 1.3 mm vs 7.16 ± 1.8 mm; P = .001), with higher stent oversizing (36.87% ± 23.6% vs 5.52% ± 15.0%; P < .001), and with a higher angle of curvature (124.33 ± 86.1 degrees vs 57.71 ± 27.9 degrees; P < .001). All cases of thrombosis were related to renal arteries (two left renal arteries, two right renal arteries, and two polar renal arteries). The freedom from thrombosis at 24 months was 92%. The area under the curve for the angle of curvature was 0.802 (95% confidence interval, 0.661-0.943; P = .013), and the cutoff point was established at 59.5 degrees (sensitivity, 100%; specificity, 60.4%). The receiver operating characteristic curve for the stent oversize showed an area under the curve of 0.903 (95% confidence interval, 0.821-0.984; P = .001), and the cutoff point was 14.5% (sensitivity, 100%; specificity, 77.1%). A higher hemodynamic force was associated with thrombosis (23.35 × 10−3 N ± 18.7 × 10−3 N vs 12.31 × 10−3 N ± 6.8 × 10−3 N; P = .001) but not with endoleak (P = .796). The freedom from endoleak and thrombosis at 24 months was 86% and 90%, respectively. ConclusionsLonger stents should be preferred to avoid type III endoleak. A higher angle of curvature leads to a higher hemodynamic force that results in a higher rate of thrombosis. Accordingly, we recommend maintaining the angle of curvature under 59.9 degrees. Small vessels and excessive stent oversizing entail a higher risk of thrombosis; as such, we advise a maximum stent oversize of 14.5%. Renal arteries are more susceptible to thrombosis, whereas visceral arteries are more prone to endoleak.

PERFORMANCE OF ULTRA-HIGH RESOLUTION CT OF INSTENT RESTENOSIS OF BELOW 3.0MM CORONARY STENT

Accuracy of coronary computed tomography of small coronary stents (<3.0mm) is limited. We have investigated the diagnostic performance of ultra-high resolution computed tomography (URCT) which has 0.25mm slice thickness in patients who received small coronary stents (<3.0mm). Consecutive patients

Abstract WP23: Is There Increased Incidence of Subarachnoid Hemorrhage With Use of Stentrievers in Distal Circulation?

Background: Multiple recent positive endovascular trials have proven mechanical thrombectomy as standard of care for large vessel occlusion (LVO) of the Anterior Circulation (AC). Post-thrombectomy subarachnoid hemorrhage (PT-SAH) is a known complication of this procedure. The aim of this study was to compare the incidence of SAH in proximal (ICA terminus and MCA M1) versus distal (MCA M2 and beyond) LVOs with use of stentrievers. Methods: Retrospective analysis of patients who underwent anterior circulation acute ischemic stroke interventions (AISI) at a community based, university affiliated comprehensive stroke center during a 5 year period (2014-2019) was done. AISI using stentrievers were separated in 2 groups based on location of LVO (Proximal and Distal). Post procedure CT heads were reviewed for SAH in location of stent deployment. Results: 2980 patients presented with acute ischemic stroke during the pre-specified time period. Of those, 2,682 were anterior circulation strokes. Of those, 373 received AISI. Stentrievers were used in 193 patients. Proximal occlusions (ICA terminus and MCA M1) were placed into Group A (n=150). Distal occlusions (MCA M2 and beyond) were placed into Group B (n=43). Group A had 6% SAH (n=9); Group B had 16% SAH (n=7) (p value &lt;0.05). Conclusion: This study reveals an increased incidence of PT-SAH for distal LVOs. Main limitation of the study is the small sample size. Next generation stentrievers with smaller stent size and different design may decrease incidence of PT-SAH. Larger prospective RCTs are warranted to validate these results.

Does a small stent size increase the risk of post-operative complications following reconstructive robotic surgery in the pediatric population?

The use of double J stents (DJS) is common practice during robotic reconstructive surgeries in the pediatric population. Some studies claimed that a small stent diameter is prone to obstruction and migration, thus might increase the number of post-op complications. The aim of this study was to evaluate whether the use of a small stent size leads to higher complication rate following robotic reconstructive surgery in children. We have retrospectively reviewed the medical files of patients, who underwent reconstructive robotic surgery with insertion of 3Fr or 4Fr DJS over a 3-year period, from two medical centers. The data included demographics, operation type, DJS size, post-op complications and duration of hospital stay. The study included 47 patients, 33 (70.2%) were male. The mean age was 34 months (range 3–192 months). 3Fr DJS was used in 13 (27.7%) patients and 4Fr stent was utilized in the remaining 34 (72.3%) children. 3Fr stents were more frequently used in younger children (14 vs 42 months, p < 0.01). There were 3 (6.4%) stent-related post-op complications, two leaks in the 4Fr stent group and one stent migration in the 3Fr group. No statistically significant difference in post-operative complication rate, was found between the two DJS groups (p = 0.631). No correlation was found between DJS size and type of complication (r = 0.238, p = 0.107 for dislodgement; r = − 0.130, p = 0.382 for leaks, respectively). Our data show that the use of small DJS size does not lead to increased post-op complication rate and is safe and durable in pediatric robotic surgery.

Geometric Analysis of Fenestrated and Multibranched Aortic Endografts – Relevance of Branches’ Angulation for Type III Endoleaks and Branch Thrombosis

Introduction: Endovascular treatment of thoracoabdominal aortic aneurysms (TAAA) is the gold standard procedure in most vascular centers. The goal of this study is to determine geometric risk factors for the development of type III endoleaks and branch thrombosis in patients treated with fenestrated (F-) or multibranched (B-) endovascular aneurysm repair (EVAR). The primary endpoint was the post-operative end-stent angulation for both FEVAR and BEVAR and its relevance in type III endoleak and branch thrombosis. Methods: From November 2013 to March 2018, consecutive patients with TAAA treated with a FEVAR of BEVAR were selected. Demographic variables, aneurysm anatomy and endografts’ conformation were analyzed retrospectively. Results: 24 patients underwent CTA before and after FEVAR (n=8) and BEVAR (n=16), and 86 vessels were successfully catheterized (celiac artery n=14, superior mesenteric artery n=24, right renal artery n=24, left renal artery n=22, polar renal artery n=2). All patients were considered ASA III and the median age was 72 years (49-81). The mean aneurysm diameter was 67.4mm (54.4-92.7). The mean follow-up period was 22.7 months and the rate free of type III endoleak and thrombosis at 24 months were 89% and 88%, respectively. All the FEVAR vessels (n=26) were catheterized using 1 stent, while 16.7% (n=10) of the BEVAR vessels (n=60) required 2 stents. The total stent longitude in FEVAR was significantly shorter than in BEVAR (26.67±4.4mm vs 6.50.63±8.51mm, p=0.000), as was the radius of curvature (FEVAR 34.75±18.7º; BEVAR 64.92±18.2º, p=0.000). There were no significant differences between FEVAR and BEVAR in terms of rate of type III endoleak (p=0.240) or branch thrombosis (p=0.544). The overall rate of branch thrombosis was 9.3% (n=8) and was more frequent in smaller vessels (5.00±1.25mm vs 7.30±1.8mm, p=0.001) and in vessels with higher stent oversizing (36.87±23.6% vs 3.57±13.8%, p=0.000). The overall rate of type III endoleaks was 11.6% (n=10), and all cases were associated with 4-branch endografts (p=0.030). 60% of the vessels that required 2 stents showed a type III endoleak, which was significantly higher than the vessels treated with 1 stent (5.3%) (p=0.000). A higher rate of type III endoleak was observed in greater vessels (7.63±0.59mm vs 7.04±2.0mm, p=0.029) and with wider stents (8.40±1.1mm vs 7.18±1.2mm, p=0.002). A positive correlation was found between the presence of endoleak and the need for 2 stents per vessel (p=0.000) but not with the total longitude of the stent (p=0.103). The end-stent angulation, the radius of curvature and the total stent longitude did not entail a higher rate of endoleak (p=0.719; p=0.634; p=0.314 respectively) or thrombosis (p=0.424; p=0.102; p=0.205 respectively). Conclusion: In our series, the end-stent angle does not relate with a higher risk of type III endoleak nor with branch thrombosis, neither does the radius of curvature or the total stent longitude. Care must be taken when measuring the vessel’s diameter, in order to choose the adequate stent size, as small vessels and excessive stent oversizing entail a higher risk of branch thrombosis. Longer stents should be considered rather than using more than one, since a higher number of stents per vessel associates a higher risk of endoleak.

Long-term outcome of percutaneous intervention for pulmonary vein stenosis after pulmonary vein isolation procedure.

Report long-term outcomes of percutaneous intervention in patients with pulmonary vein stenosis (PVS) after pulmonary vein isolation (PVI) from a single center over 16 years. Outcome reports of percutaneous intervention for PVS resulting from PVI are limited. Retrospective review of all patients with PVS after PVI who underwent percutaneous intervention at the Cleveland Clinic Foundation between January 2000 and December 2016. A total of 205 patients underwent cardiac catheterization for PVS during the study period. Completely occluded veins which could not be recanalized occurred in six patients. Of the remaining 199 patients, 27 (14%) were lost to follow-up, leaving 172 patients with 276 veins for analysis. Balloon angioplasty was performed in 62 veins and stent implantation in 250 (primary in 214, to treat postdilation restenosis in 36). Re-intervention occurred in 45/62 (73%) balloon-dilated veins and 45/250 (18%) stented veins. Freedom from re-intervention at 1 and 5 years was 90 and 73% following stenting versus 40 and 23% following balloon dilation (p < .001, Hazard ratio (HR) = 5.7). Veins with stent diameter ≥7 mm (n = 231) had greater freedom from re-intervention (95% at 1 year, 79% at 5 years) than veins with stents <7 mm (43% at 1 year, 9% at 5 years), p < .001. There was clear symptomatic improvement after intervention and no procedural mortality. Stent implantation at ≥7 mm for PVS after PVI is associated with low rates of re-intervention, in contrast to balloon dilation and stenting with small conventional stents.

P5626The clinical impact of the angle of OCT detected irregular protrusion after primary PCI at the STEMI culprit lesions

Abstract Background and introduction The percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) shows worse clinical outcomes than that for stable angina. As the one of the reasons, a recent optical coherence tomography (OCT) registry showed that the presence of irregular protrusion (IP)after coronary stenting was the worse predictor of 1-year device-oriented clinical end points. However, the impact of the quantitative findings on IP has not been well investigated in ACS patients. Aim To investigate the clinical impact of the post stent OCT findings, especially IP, detected by OCT after coronary stenting in ACS patients. Methods Consecutive 256 ACS lesions treated with OCT-guided PCI in our Medical University Hospital from January 2013 to November 2016 was retrospectively analyzed. In 256 lesions, 173 lesions were enrolled which had ST-elevation acute myocardial infarction (STEMI) with the onset to recanalization time within 720 minutes. In 170 lesions, the OCT images were available. In OCT image, IP was detected in 140 lesions (82.3%). Quantitative analysis of IP in post-procedure OCT imaging was observed to identify the OCT predictors for clinical endpoint including cardiac death, target vessel revascularization ant stent thrombosis in 1 year after index PCI. Result In post-procedure OCT findings, stent edge dissection was detected in 32.4% of lesions. Incomplete stent apposition was detected in 74.1%. Maximum angle of irregular protrusion was 194±86 degree and the incidence of maximum IP angle &gt;180 degree was 52.9%. Maximum height of IP was 0.26±0.11mm. Small minimal stent area, defined as a lesion with minimal stent area &lt;5.0 mm2 in a drug-eluting stent or &lt;5.6 mm2 in a bare metal stent, was observed in 32.4% of lesions. Maximum IP angle and that of &gt;180degree was significantly associated with the clinical endpoint (p=0.0259 and 0.0429, respectively). Conclusion In STEMI patients, IP was frequently observed in post-procedure OCT imaging during primary PCI. The maximum angle of IP was significantly associated with the clinical end points. The prognostic impact of maximum IP angle in STEMI patient needs further investigations.