Stented Vessel Research Articles

Outcomes After Fenestrated and Branched Endografts for Juxtarenal, Pararenal, and Thoraco-abdominal Aortic Aneurysm Repair: 1-year Follow-up

Introduction: The aim of this study was to evaluate the 1-year follow-up results of fenestrated (FEVAR) and branched (BEVAR) endovascular aortic repair in terms of mortality, target visceral vessel patency, endoleaks, and reintervention rates. Methods: All consecutive patients treated with FEVAR or BEVAR in a single center were included in a prospectively maintained database. Analyses of outcomes included technical success, operative mortality and late events with regard to target vessel stent patency, reintervention, endoleak, and mortality during follow-up. Survival, target vessel stent patency, and reinterventions during follow up were subjected to Kaplan-Meier analysis. Results: A total of 38 patients were treated for juxta/pararenal abdominal aortic aneurysm (n=23), thoraco-abdominal aneurysm (n=12) or type I endoleak (n=3). 24 FEVAR (22 Terumo Aortic Fenestrated Anaconda endografts, 2 JOTEC E-xtra Design Engineering) and 15 BEVAR (inner or outer branched JOTEC E-xtra Design Engineering) procedures were performed from 2013 to December 2018. 97.4% of patients were male, mean age was 72.3 (±7.3) years and mean aortic diameter was 69.4 (±16.6) mm. 6 patients had previously undergone at least one open/endovascular aortic procedure. Technical success (stent graft implantation with patent stented target vessels and no Type I/III endoleak) was 97.4%. Revascularization was successful in 129 of 131 target vessels (97.7%). In two patients catheterization/stenting of one renal artery was not possible. Survival at 30 days was 86.8%. 4 patients died within 30 days. Mean follow-up was 15.1 (±17.2) months. Survival at 1 year was 67.5%. During follow up,10 patients died, one of them aneurysm-related. Freedom from endoleak at 1 year was 70.7%; 5 type I endoleaks treated and 2 type II endoleaks in follow-up. Freedom from reintervention at 1 year was 67.5%; 5 type 1 endoleaks (2 type Ia, 3 type Ib), 1 dissection, 3 access vessel complications (1 external iliac thrombosis, 2 common femoral artery stenosis/thrombosis). Freedom from target vessel thrombosis at 1 year was 93.1%. Conclusion: Total endovascular repair in juxta/pararenal abdominal aortic aneurysm and thoracoabdominal aneurysms has favorable midterm results. Most of the reinterventions were performed on renal arteries endoleaks or on vessel access complications. Disclosure: Nothing to disclose

Early and Mid-Term Outcomes of Open Repair, Fenestrated Stent Graft and Chimney Graft in Juxtarenal Abdominal Aortic Aneurysms

Introduction - Juxtarenal abdominal aortic aneurysm (JAAA) is defined as an infrarenal AAA that is adjacent to or involving the lower margin of the renal artery origins1. Recently, promising results have been reported in peer reviewed journals after fenestrated and chimney graft approaches to repair of JAAA2,3. Open repair, fenestrated endovascular aneurysm repair (FEVAR) and chimney endovascular aneurysm repair (Ch-EVAR) are effective methods to treat this condition, but the comparative effectiveness of these treatment modalities is unclear4. Upon completion of a hybrid vascular intervention room at our institution and careful planning and sizing, we started a prospective registry of all JAAA cases performed. Here we present our retrospectively analyzed results, including short and midterm follow-up results in patients with JAAA treated using either endovascular or open repair. Methods - We retrospectively reviewed patients with JAAA (n= 75) who underwent chimney grafts (Ch-EVAR, n = 23), fenestrated stent grafts (FEVAR, n = 20) or open repair (OR, n = 32) between January 2011 and December 2016 at a single institution. Our primary endpoint was peri-operative mortality. Secondary endpoints included renal function impairment, new-onset dialysis, procedural details and postoperative complications. Descriptive statistics are reported as mean ± standard deviation for continuous data and categorical data are presented as number and percentage. Kaplan-Meier analysis was used to estimate freedom from late re-intervention, primary patency of targeted vessel stent grafts and overall survival. Results - There were no statistically significant differences in baseline characteristics among the three groups. Perioperative mortality was not significantly different between groups: 4.3% (1/23) in the Ch-EVAR group, 0% in the FEVAR group and 3.1% (1/32) in the OR group(p = 0.532). Mean follow up time was 36.7 months. There were no statistically significant differences among the three groups in secondary endpoints, except for increased blood loss in the open repair group when compared to the endovascular groups. There were no statistically significant differences in overall survival among groups (p=0.282). Estimated targeted vessel stent patency at 1 and 4 years were 89.5% and 89.5% in the Ch-EVAR group and 93.8% and 93.8% in the FEVAR group, respectively. There were no statistically significant differences in estimated freedom from late re-intervention among groups (82.3% in the Ch-EVAR group, 77.2% in the FEVAR group and 96.4% in the OR group) Conclusion - We were unable to show a ststistically significant difference in outcomes among the treatment options for JAAA repair, which may be due to the size of our series. Nevertheless, our results show that after careful patient selection, we are able to offer our patients good results with fenestrated and chimney graft techniques that are comparable to open surgical procedures, but with a much faster recovery time. All three approaches (Ch-EVAR, FEVAR and open surgery) are effective treatment options for JAAA repair and have comparable short and mid-term outcomes in well-selected patients. Long term follow-up results are needed to determine the optimal management of JAAA. References·Jongkind V, Yeung KK, Akkersdijk GJ, Heidsieck D, Reitsma JB, Tangelder GJ, Wisselink W. Juxtarenal aortic aneurysm repair. J Vasc Surg. 2010;52:760-767·Verhoeven EL, Vourliotakis G, Bos WT, Tielliu IF, Zeebregts CJ, Prins TR, Bracale UM, van den Dungen JJ. Fenestrated stent grafting for short-necked and juxtarenal abdominal aortic aneurysm: An 8-year single-centre experience. Eur J Vasc Endovasc Surg. 2010;39:529-536·Donas KP, Torsello GB, Piccoli G, Pitoulias GA, Torsello GF, Bisdas T, Austermann M, Gasparini D. The protagoras study to evaluate the performance of the endurant stent graft for patients with pararenal pathologic processes treated by the chimney/snorkel endovascular technique. J Vasc Surg. 2016;63:1-7·Katsargyris A, Oikonomou K, Klonaris C, Topel I, Verhoeven EL. Comparison of outcomes with open, fenestrated, and chimney graft repair of juxtarenal aneurysms: Are we ready for a paradigm shift? J Endovasc Ther. 2013;20:159-169

Accuracy of RESOLVE score derived from coronary computed tomography versus visual angiography to predict side branch occlusion in percutaneous bifurcation intervention

IntroductionVisually estimated angiographic V-RESOLVE score was developed as a simple and accurate prediction tool for side branch (SB) occlusion in patients undergoing coronary bifurcation intervention. Data on the use of coronary computed tomography angiography (coronary CTA) for guiding percutaneous coronary intervention in bifurcation lesions is scarce. ObjectivesWe aimed to validate the ability of quantitative CTA-derived RESOLVE score for predicting SB occlusion in coronary bifurcation intervention and to compare its predictive value with that of the angiography-based V-RESOLVE score. MethodsWe included 363 patients with 400 bifurcation lesions. Angiographic V-RESOLVE score and CTA-derived RESOLVE score were calculated utilizing the weights from the QCA-based RESOLVE score. The scoring systems were divided into quartiles, and classified as the non-high-risk group and the high-risk group. Accuracy was assessed using areas under the receiver-operator characteristic curve (AUC). SB occlusion was defined as any decrease in Thrombolysis in Myocardial Infarction flow grade (including the absence of flow) in the SB after main vessel stenting. ResultsIn total, 28 SB occlusions (7%) occurred. CTA-derived RESOLVE and V-RESOLVE scores achieved comparable predictive accuracy (0.709 vs. 0.752, respectively, p = 0.531) for predicting SB occlusion, and the analysis of AUC for each constituent element of the scores did not show any significant difference between CTA and visual angiography. The total net reclassification index was −18.6% (p = 0.194), and there were no significant differences in the rates of SB occlusion in the non-high-risk group (4.9% vs. 3.8%, p = 0.510) and the high-risk group (13.8% vs. 18.6%, p = 0.384) between CTA-derived RESOLVE and V-RESOLVE scores. ConclusionsThe quantitative CTA-derived RESOLVE score is an accurate and reliable alternative to the visually estimated angiographic V-RESOLVE score for prediction of SB occlusion in coronary bifurcation intervention. Clinical trial registrationURL: https://www.clinicaltrials.gov. Unique identifier: NCT03709836.

A novel, rapid, and low cost method for preparing tissues with metallic stents for routine histology.

Coronary artery stenting has become a common procedure and cardiovascular pathology specimens containing these metallic stents are accordingly becoming common. Histologic examination of stented vessels is imperative, but special techniques are needed due to the presence of metal within the tissue. We describe a rapid and inexpensive method for preparing stented vascular specimens for routine histology suitable for use in almost any histology laboratory. After formalin fixation and decalcification, stented vascular segments were freeze-embedded and sectioned using a handheld power micro cutoff wheel tool into ~1mm slices. Sections were allowed to thaw and the strut shards removed with fine forceps. No longer containing metal, the sections were processed for routine paraffin embedding, microtomy and staining. Histologic sections showed only minor tissue disruption around the stent struts. In our experience with 25 stented arteries (mean interval from implantation 5.6 years), the mean subjective section quality score was 4.1 out of 5. The position of each strut could easily be determined, along with neointimal in-stent restenosis and thrombosis. Local reaction to each strut could be surmised even if minor tissue disruption occurred. The entire process was completed in 2-3 days. The incremental cost over that of routine histology is nominal. This method for examining stented vascular segments histologically could readily be applied in most pathology laboratories and serves as a highly practical solution to dilemma of examining stents histologically.

Comparison of diagnostic performance in assessing the rewiring position into a jailed side branch between online 3D reconstruction systems version 1.1 and 1.2 derived from optical frequency domain imaging

The three-dimensional reconstruction of optical coherence tomography and optical frequency domain imaging (3D-OCT/OFDI) helps optimize bifurcation percutaneous coronary interventions (PCIs) with side branch (SB) dilatation by identifying the optimal rewiring position. 3D-OCT/OFDI’s diagnostic performance for assessing the rewiring position into a jailed SB is unknown. We retrospectively evaluated the diagnostic performances of a conventional (ver. 1.1) and a new (ver. 1.2) online 3D-OFDI reconstruction system based on an offline 3D reconstruction system’s performance. We analyzed 45 patients’ 52 OFDI pullbacks with main vessel stenting followed by rewiring into a jailed SB for coronary bifurcation lesions. We counted the undetected stent struts in the polygon of confluence as the stent detection performance. We assessed the diagnostic agreement regarding the rewiring position into a jailed SB by the three 3D reconstruction systems. The percentage of undetected struts and the diagnostic agreement of ver.1.2 were significantly better than those of ver.1.1 [5.1 ± 5.1% vs. 30.2 ± 14.2%; p < 0.0001, and 94.2% (49/52) vs. 76.9% (40/52); p = 0.0120]. The new online 3D-OFDI reconstruction system provides better diagnostic performance than the conventional online system for assessing the rewiring position into a jailed SB.

A particle-based model for endothelial cell migration under flow conditions

Endothelial cells (ECs) play a major role in the healing process following angioplasty to inhibit excessive neointima. This makes the process of EC healing after injury, in particular EC migration in a stented vessel, important for recovery of normal vessel function. In that context, we present a novel particle-based model of EC migration and validate it against in vitro experimental data. We have developed a particle-based model of EC migration under flow conditions in an in vitro vessel with obstacles. Cell movement in the model is a combination of random walks and directed movement along the local flow velocity vector. For model calibration, a set of experimental data for cell migration in a similarly shaped channel has been used. We have calibrated the model for a baseline case of a channel with no obstacles and then applied it to the case of a channel with ridges on the bottom surface, representative of stent strut geometry. We were able to closely reproduce the cell migration speed and angular distribution of their movement relative to the flow direction reported in vitro. The model also reproduces qualitative aspects of EC migration, such as entrapment of cells downstream from the flow-disturbing ridge. The model has the potential, after more extensive in vitro validation, to study the effect of variation in strut spacing and shape, through modification of the local flow, on EC migration. The results of this study support the hypothesis that EC migration is strongly affected by the direction and magnitude of local wall shear stress.

Do ultrathin strut bare-metal stents with passive coating improve efficacy in large coronary arteries? Insights from the randomized, multicenter BASKET-PROVE trials

BackgroundThe new generation thinner-strut silicon carbide (SiC) coated cobalt chromium (CoCr) bare-metal stents (BMS) are designed to accelerate rapid endothelialisation and reduce thrombogenicity when implanted in coronary arteries. However, smaller studies suggest higher rates of symptomatic restenosis in patients receiving the newer generation BMS.We investigated the efficacy of a newer generation ultrathin strut silicon-carbide coated cobalt-chromium (CoCr) BMS (SCC-BMS) as compared to an older thin-strut uncoated CoCr BMS (UC-BMS) in patients presenting with coronary artery disease requiring stenting of large vessels (≥3.0 mm).MethodsAll patients randomized to SCC- (n = 761) or UC-BMS (n = 765) in the two BASKET-PROVE trials were included. Design, patients, interventions and follow-up were similar between trials except differing regimens of dual antiplatelet therapy. The primary endpoint was clinically driven target-vessel revascularization within 24 months. Safety endpoints of cardiac death, non-fatal myocardial infarction (MI), and definite/probable stent thrombosis (ST) were also assessed. We used inverse probability weighted proportional hazards Cox regressions adjusting for known confounders.ResultsDemographics, clinical presentation, and risk factors were comparable between the groups, but patients receiving SCC-BMS underwent less complex procedures. The risk for clinically driven TVR was increased om the SCC-BMS group compared to the UC-BMS group (cumulative incidence, 10.6% vs. 8.4%; adjusted relative hazard [HR], 1.49 [95% CI, 1.05–2.10]). No differences in safety endpoints were detected, cardiac death (1.6% vs. 2.8%; HR, 0.62 [CI, 0.30–1.27]), non-fatal MI (3.2% vs. 2.5%; HR, 1.56 [CI, 0.83–2.91]), and definite/probable ST (0.8% vs. 1.1%; HR, 1.17 [CI, 0.39–3.50]). Differences in strut thickness between the two stents did not explain the association between stent type and clinically driven TVR.ConclusionsIn patients requiring stenting of large coronary arteries, use of the newer generation SCC-BMS was associated with a higher risk of clinically driven repeat revascularization compared to the UC-BMS with no signs of an offsetting safety benefit.

Magnetic Particle Imaging: Artifact-Free Metallic Stent Lumen Imaging in a Phantom Study.

To illustrate the potential of magnetic particle imaging (MPI) for stent lumen imaging in comparison with clinical computed tomography (CT) and magnetic resonance imaging (MRI). Imaging of eight tracer-filled, stented vessel phantoms and a tracer-filled, non-stented reference phantom for each diameter was performed on a preclinical MPI scanner: eight commercially available coronary stents of different dimensions (diameter: 3-4mm; length: 11-38mm) and materials (stainless steel, platinum-chromium) were implanted into silicone vessel phantoms. For comparison, all vessel phantoms were also visualized by MRI and CT. Two radiologists assessed the images regarding stent-induced artifacts using a 5-point grading scale. The visualization of all stented vessel phantoms was achieved without stent-induced artifacts with MPI. In contrast, MRI and CT images revealed multiform stent-induced artifacts. Given its clinical introduction, MPI has the potential to overcome the disadvantages of MRI and CT concerning the visualization of the stent lumen.

Echocardiographic guidance of interventions in adults with congenital heart defects.

Cardiac catheterization procedures have revolutionized the treatment of adults with congenital heart disease over the past six decades. Patients who previously would have required open heart surgery for various conditions can now undergo percutaneous cardiac catheter-based procedures to close intracardiac shunts, relieve obstructive valvular lesions, stent stenotic vessels, or even replace and repair dysfunctional valves. As the complexity of percutaneous cardiac catheterization procedures has increased, so has the use of echocardiography for interventional guidance in adults with congenital heart disease. Transthoracic, transesophageal, intracardiac, and three-dimensional echocardiography have all become part and parcel of the catheterization laboratory experience. In this review, we aim to describe the different echocardiographic techniques and their role in various cardiac catheterization interventions specific to adults with congenital heart disease.

2381Low-intensity pulsed ultrasound ameliorates DES-induced coronary adventitial inflammation and hyperconstricting responses in pigs in vivo - A novel non-invasive therapy for coronary inflammation

Abstract Background We previously demonstrated that coronary adventitial inflammation plays important roles in the pathogenesis of coronary artery spasm, including drug-eluting stent (DES)-induced coronary hyperconstricting responses, in pigs and humans. Indeed, the coronary adventitia has recently attracted much attention as the important site for vascular inflammation. However, a direct therapeutic approach to the coronary adventitia remains to be developed. We have developed a non-invasive low-intensity pulsed ultrasound (LIPUS) therapy for angina, which exerts anti-inflammatory effects through improved coronary microcirculation. Purpose In this study, we aimed to examine whether our LIPUS therapy ameliorates DES-induced coronary hyperconstricting responses in pigs in vivo, and if so, what mechanisms are involved. Methods An everolimus-eluting stent (EES) was implanted into the left anterior descending (LAD) coronary artery in normal male pigs. They were randomly assigned to the LIPUS or the sham therapy groups. After EES implantation, in the LIPUS group, LIPUS (32 cycles, 193 mW/cm2) was applied to the heart at 3 different levels (proximal and distal stent edges and middle portion of the stent) through X-ray for 20 min at each level for every other day for 2 weeks (6 days in total) (Figs. 1A, 1B). The sham therapy group was treated in the same manner but without LIPUS. At 4 weeks after the procedure, we performed coronary angiography to examine coronary vasoconstricting responses to intracoronary serotonin in vivo. Finally, stented coronary vessels were harvested for immunohistochemistry of vasa vasorum, lymphatic vessels (LYVE-1), sympathetic nerve fibers (SNF), vascular inflammation (macrophages and IL-1β expression), Rho-kinase expression and activity as evaluated by phosphorylated myosin phosphatase target subunit-1 (pMYPT-1). Results Coronary vasoconstricting responses to intracoronary serotonin were significantly enhanced in the sham therapy group but were significantly suppressed in the LIPUS group at the DES edges in the LAD, whereas those responses were comparable at the non-DES implanted segments in the left circumflex (LCx) coronary arteries between the 2 groups. (Figs. 1C, 1D). Furthermore, in vivo lymph transport speed was significantly faster in the LIPUS group than in sham group (Figs. 1E–1G). Histological analysis showed that except vasa vasorum formation, the number of lymphatic vessels, adventitial inflammatory cells infiltration, Rho-kinase expression and activity were all significantly enhanced in the sham therapy group and were significantly suppressed in the LIPUS group (Figs. 1G–1K). Figure 1 Conclusion We were able to develop a non-invasive LIPUS therapy for coronary functional abnormalities caused by chronic adventitial inflammation in pigs in vivo, for which multiple beneficial effects appear to be involved (Fig. 1L).

P2690Safety and effectiveness of thin-strut DES for bifurcated coronary lesions not involving left main: a RAIN (veRy thin stents for patients with left mAIn or bifurcatioN in real life) sub-analysis

Abstract Background Thinner stent struts of new DES (drug eluting stent) are associated with shorter time of reendothelialization, a reduction of shear stress and inflammation of coronary walls. Despite this great innovations their clinical safety and efficacy in challenging scenarios as non left main bifurcation coronary lesions has not been tested. Methods RAIN is a multicenter registry enrolling patients treated on bifurcated coronary lesions and left main with thin-strut DES. Baseline characteristics and procedural data were recorded. Target lesion revascularization (TLR) was the primary endpoint, whereas major adverse clinical events (MACE; composite of all-cause death, myocardial infarction (MI), target vessel revascularization (TVR), TLR and stent thrombosis (ST)) along with its single components were the secondary endpoints. A multivariate analysis to identify predictors of TLR and sub-analysis according to stenting strategy (provisional vs 2-stent technique), use of final kissing balloon (FKB) and IVUS/OCT optimization were performed. Results Data from 1803 patients (59% ACS, 61% stable CAD) treated on bifurcations were retrospectively evaluated. Follow up was available for 1685 (94%) patients for a median of 12 months (IQR 7–18). TLR occurred globally in 2.5% of cases (2.2% in provisional stenting, 3.5% in 2-stent technique). The rate of MACE was 9.4%, whereas all-cause death and MI, occurred in 4.1% and 3.2% of cases respectively. TVR and definite ST incidence were 3.7% and 1.1%. At multivariate analysis, chronic kidney disease (CKD) negatively influenced the main endpoint (HR 1.95, 95% CI 1.06–3.6, p=0.03), whereas post-dilatation (HR 0.56, 95% CI 0.3–0.93, p=0.04) and provisional stenting resulted being protective factors. FKB reduced TLR occurrence at FU only in 2-stent technique (p=0.03), whereas intracoronary imaging (performed in 29% of patients) were uninfluential. Conclusion Very thin-strut DES represents a highly effective solution in bifurcation lesions. The risk of TLR is reduced by post-dilatation and provisional stenting. FKB is recommended in 2-stent technique, whereas further studies are required to address the impact of intracoronary imaging in this setting.

125Incidence and outcomes of bailout stenting following use of drug coated balloon

Abstract Background The incidence of bailout stenting post-drug coated balloon use (DCB) in the literature has been more than 10%; ranging up-to 21% in Bello trial and this variation could be due to the different criteria used to consider bailout stenting and may also reflect aggressive pre-dilatation. Our eyes are trained to expect stent like result and anything less is considered sub-optimal and this could be one of the reasons for high incidence of bailout stenting. The current recommendation is to use drug eluting stent (DES) for bailout stenting and hence raising in the possibility of drug toxicity or maybe even synergistic effect from combination of Paclitaxel (DCB) and limus (DES). Aim We have evaluated the incidence and outcomes of patients needing bailout stenting in our centre. Methods and results We evaluated all patients who were treated with DCB between January 2016-August 2017. Bailout stenting per lesion were identified and studied for endpoints which included cardiac death, target vessel MI, stent thrombosis, target lesion revascularization and target vessel revascularisation. Between the study period; 468 lesions (in 364 patients) were treated with paclitaxel DCB (Sequent Please, B Braun, Germany). Bailout stenting was required in 23 lesions (4.9%) and of which 12 (52%) was for flow limiting dissections (type C or more) and the remaining 11 was for recoil of more than 50%. Majority of the lesions were de novo (18; 78%). All bailout stenting was performed with third generation limus eluting stents. During a median follow-up of 18.14 months; range; 7–33 months, there was no cardiac death and target vessel MI occurred in 1 patient (4.3%), TLR and TVR were in 3 lesions (13%). MACE rate (combination of cardiac death, target vessel MI and TVR) was 13%. There were no cases of stent thrombosis as per the ARC definition. Conclusion One of the highlighting features of our study is very low-rates of bailout stenting. This may be due to our criteria of not stenting mild dissections (unless they are flow limiting) and also to accepting recoil of up-to 50% post-DCB use. The outcome in bailout stenting group is acceptable especially with hard endpoints (cardiac death, target vessel MI and stent thrombosis) although TLR and TVR rates were higher indicating synergistic effect of paclitaxel and limus may not offer additional benefits.

The effects of stenting on hemorheological parameters: An in vitro investigation under various blood flow conditions.

Despite their wide clinical usage, stent functionality may be compromised by complications at the site of implantation, including early/late stent thrombosis and occlusion. Although several studies have described the effect of fluid-structure interaction on local haemodynamics, there is yet limited information on the effect of the stent presence on specific hemorheological parameters. The current work investigates the red blood cell (RBC) mechanical behavior and physiological changes as a result of flow through stented vessels. Blood samples from healthy volunteers were prepared as RBC suspensions in plasma and in phosphate buffer saline at 45% haematocrit. Self-expanding nitinol stents were inserted in clear perfluoroalkoxy alkane tubing which was connected to a syringe, and integrated in a syringe pump. The samples were tested at flow rates of 17.5, 35 and 70 ml/min, and control tests were performed in non-stented vessels. For each flow rate, the sample viscosity, RBC aggregation and deformability, and RBC lysis were estimated. The results indicate that the presence of a stent in a vessel has an influence on the hemorheological characteristics of blood. The viscosity of all samples increases slightly with the increase of the flow rate and exposure. RBC aggregation and elongation index (EI) decrease as the flow rate and exposure increases. RBC lysis for the extreme cases is evident. The results indicate that the stresses developed in the stent area for the extreme conditions could be sufficiently high to influence the integrity of the RBC membrane.

Location-Specific Comparison Between a 3D In-Stent Restenosis Model and Micro-CT and Histology Data from Porcine In Vivo Experiments

BackgroundCoronary artery restenosis is an important side effect of percutaneous coronary intervention. Computational models can be used to better understand this process. We report on an approach for validation of an in silico 3D model of in-stent restenosis in porcine coronary arteries and illustrate this approach by comparing the modelling results to in vivo data for 14 and 28 days post-stenting.MethodsThis multiscale model includes single-scale models for stent deployment, blood flow and tissue growth in the stented vessel, including smooth muscle cell (SMC) proliferation and extracellular matrix (ECM) production. The validation procedure uses data from porcine in vivo experiments, by simulating stent deployment using stent geometry obtained from micro computed tomography (micro-CT) of the stented vessel and directly comparing the simulation results of neointimal growth to histological sections taken at the same locations.ResultsMetrics for comparison are per-strut neointimal thickness and per-section neointimal area. The neointimal area predicted by the model demonstrates a good agreement with the detailed experimental data. For 14 days post-stenting the relative neointimal area, averaged over all vessel sections considered, was 20 ± 3% in vivo and 22 ± 4% in silico. For 28 days, the area was 42 ± 3% in vivo and 41 ± 3% in silico.ConclusionsThe approach presented here provides a very detailed, location-specific, validation methodology for in silico restenosis models. The model was able to closely match both histology datasets with a single set of parameters. Good agreement was obtained for both the overall amount of neointima produced and the local distribution. It should be noted that including vessel curvature and ECM production in the model was paramount to obtain a good agreement with the experimental data.

Factors Affecting the Degree of Angular Remodeling in Stent-Assisted Coiling of Bifurcation Aneurysms

Background: Stent-assisted coiling (SAC) leads to significant changes in the vascular angle altering the bifurcation geometry and the hemodynamics at the bifurcation apex. It is believed that the stent alone exerts this effect, but other possible factors have not been studied. Purpose: To study the factors contributing to angular remodeling following SAC of bifurcation aneurysms including the anatomical, stent-related, and coil-related factors. Materials and Methods: We reviewed 43 basilar and carotid bifurcation aneurysms treated by SAC using Neuroform EZ (n = 28), Enterprise (n = 8), and Lvis Jr. (n = 7) stents. The bifurcation angle between the mother and stented daughter vessel was measured in 4 settings: pretreatment, poststenting, postcoiling, and at delayed follow-up (6–12 months). The degree of stent-induced angular remodeling was calculated by subtracting the poststenting bifurcation angle from the pretreatment one, while the coil-induced angular remodeling was calculated as the difference between the postcoiling and poststenting bifurcation angle. The immediate postprocedural degree of angular remodeling is the sum of the stent- and coil-induced angular remodeling. We studied the effect of several factors including the pretreatment bifurcation angle, aneurysm site, diameter of parent vessel, stent type, stent length in the daughter vessel, postoperative actual in situ coil size, and packing density. Results: The mean degree of stent-induced and coil-induced angular remodeling was 10.2 (0–47) and 4.53 (–7 to 30), respectively. The immediate postprocedural and delayed angular remodeling was 14.8 (–4 to 47) and 4.75 (–12 to 40), respectively. The degree of immediate remodeling was significantly affected by the actual in situ coil size (p = 0.017), and the pretreatment bifurcation angle (p = 0.024). Linear regression was carried out and the pretreatment bifurcation angle was defined as a predictor. The degree of delayed remodeling is significantly affected only by the pretreatment bifurcation angle (p = 0.011). Conclusion: Immediate angular remodeling following SAC of bifurcation aneurysms can happen after stenting or coiling or both. This is the first study reporting the role of the coils as an additional factor beside the stent in inducing immediate angular changes; this effect is correlated to the size of the coils. The pretreatment bifurcation angle is the most consistent factor affecting the degree of both immediate and delayed angular remodeling.

Ta ion implanted nanoridge-platform for enhanced vascular responses

Bare metal stents are commonly used in interventional cardiology; they provide successful treatment because of their excellent mechanical properties, expandability ratios, and flexibility. However, their insufficient vascular affinity can induce the development of neointimal hyperplasia following arterial injury and subsequent smooth muscle cell overgrowth in the lumen of a stented vessel. Nanoengineering of the bare metal stent surface is a valuable strategy for eliciting favorable vascular responses. In this study, we introduce a target-ion-induced plasma sputtering (TIPS) technique to fabricate a platform with a favorable endothelial environment. This technique enables the simple single-step production of a Ta-implanted nanoridged surface on a stent with a complex 3D geometry that shows a clear tendency to become oriented parallel to the direction of blood flow. Moreover, the nanoridges developed show good structural integrity and mechanical stability, resulting in apparently stable morphologies under high strain rates. In vitro cellular responses to the Co–Cr, such as endothelialization, platelet activation, and blood coagulation, are considerably altered after TIPS treatment; endothelium formation is rapid and surface thrombogenicity is low. An in vivo rabbit iliac artery model is used to confirm that the nanoridged surface facilitates rapid re-endothelialization and limits the formation of neointima compared to the bare stent. These results indicate that the Ta ion implanted nanoridge platform fabricated using the TIPS technique has immense potential as a solution for in-stent restenosis and ensuring the long-term patency of bare metal stents.

Long-term Outcomes of Mesenteric Stenting and Analysis of In-Stent Restenosis Duplex Ultrasound Criteria

Duplex ultrasound velocity thresholds for stenosis within stented mesenteric vessels are not well established. The objectives of this study were to describe the long-term outcomes of mesenteric stenting for chronic mesenteric ischemia (CMI) and to determine duplex ultrasound velocities associated with clinically significant in-stent restenosis (ISR). A retrospective review of patients who underwent mesenteric stenting for CMI from a single institution between 2011 and 2018 was performed. Duplex ultrasound velocities corresponding with ISR were correlated with angiographic measurement of stenosis. Receiver operating characteristic curves were created using these data to identify the velocity thresholds with highest sensitivity and specificity for clinically significant ISR. There were 61 patients who underwent stenting of 71 arteries; 32 celiac arteries (CAs) and 39 superior mesenteric arteries (SMAs) were analyzed. Overall freedom from reintervention at 1 year, 2 years, and 3 years was 83%, 73%, and 60%. Freedom from occlusion and bypass grafting and 1 year, 2 years, and 3 years was 100%, 86%, and 86%. For CA stents, a peak systolic velocity (PSV) of 440 cm/s correlated with ≥50% ISR with 100% sensitivity and 86% specificity (Fig 1). For SMA stents, a PSV of 341 cm/s correlated with ≥50% ISR with 80% sensitivity and 52% specificity (Fig 2). Endovascular mesenteric stenting is a durable option for CMI with 86% overall patency and 60% freedom from reintervention at 3 years. Duplex ultrasound velocities for clinically significant ISR are higher than those for native mesenteric vessel stenosis. PSV thresholds of 440 cm/s for CA stents and 341 cm/s for SMA stents indicate clinically significant ISR with acceptable sensitivity and specificity rates.Fig 2Receiver operating characteristic curve and distribution of peak systolic velocity (PSV) for identifying clinically significant superior mesenteric artery (SMA) restenosis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

The Future of Cardiovascular Stents: Bioresorbable and Integrated Biosensor Technology.

Cardiovascular disease is the greatest cause of death worldwide. Atherosclerosis is the underlying pathology responsible for two thirds of these deaths. It is the age‐dependent process of “furring of the arteries.” In many scenarios the disease is caused by poor diet, high blood pressure, and genetic risk factors, and is exacerbated by obesity, diabetes, and sedentary lifestyle. Current pharmacological anti‐atherosclerotic modalities still fail to control the disease and improvements in clinical interventions are urgently required. Blocked atherosclerotic arteries are routinely treated in hospitals with an expandable metal stent. However, stented vessels are often silently re‐blocked by developing “in‐stent restenosis,” a wound response, in which the vessel's lumen renarrows by excess proliferation of vascular smooth muscle cells, termed hyperplasia. Herein, the current stent technology and the future of biosensing devices to overcome in‐stent restenosis are reviewed. Second, with advances in nanofabrication, new sensing methods and how researchers are investigating ways to integrate biosensors within stents are highlighted. The future of implantable medical devices in the context of the emerging “Internet of Things” and how this will significantly influence future biosensor technology for future generations are also discussed.

Thin, Very Thin, or Ultrathin Strut Biodegradable or Durable Polymer-Coated Drug-Eluting Stents: 3-Year Outcomes of BIO-RESORT

ObjectivesThe aim of this study was to assess the 3-year safety and efficacy of treating all-comer patients with 3 contemporary drug-eluting stents (DES). BackgroundThe BIO-RESORT (Comparison of Biodegradable Polymer and Durable Polymer Drug-Eluting Stents in an All Comers Population) (TWENTE III) randomized trial (NCT01674803) found similar 1-year safety and efficacy for the 2 biodegradable-polymer DES (i.e., ultrathin-strut cobalt-chromium Orsiro sirolimus-eluting stent [SES] and very-thin-strut platinum-chromium Synergy everolimus-eluting stent) compared with the durable-polymer thin-strut cobalt-chromium Resolute Integrity zotarolimus-eluting stent (ZES). Two-year follow-up suggested that the SES might reduce repeat revascularizations beyond 1 year compared with the ZES. MethodsA total of 3,514 all-comer patients were treated at 4 centers for coronary intervention. The main clinical endpoint, target vessel failure, was a composite of safety (cardiac death or target vessel–related myocardial infarction) and efficacy (target vessel revascularization). Secondary endpoints included the individual components of target vessel failure and stent thrombosis. ResultsThree-year follow-up data were available for 3,393 of 3,514 patients (96.6%). Target vessel failure occurred in 8.5% with SES and 10.0% with ZES (plog rank = 0.22) and in 8.8% with everolimus-eluting stents (vs. ZES, plog rank = 0.32). Rates of cardiac death, target vessel myocardial infarction, and target vessel revascularization were similar between stent groups. Landmark analyses found no statistically significant between-stent difference in repeat revascularization between 1 and 3 years. Definite or probable stent thrombosis rates were low (SES, 1.1%; everolimus-eluting stent, 1.1%; ZES, 0.9%) and similar with all 3 DES. ConclusionsDespite substantial differences in stent backbone and polymer coating, all 3 DES showed favorable 3-year safety and efficacy in all comers, without significant between-stent differences. Further follow-up is required to definitely answer the question of whether one stent might improve clinical outcomes at a later stage.

Periprocedural Management during Placement of Flow Diverters in Intracranial Aneurysms: A Clinical Report and Review of Literature

Abstract Background Placement of flow diverter (FD) is an endovascular technique where the flow to the aneurysm is directed away from the aneurysmal sac using a stent in the parent vessel. In this clinical report, the authors share their institutional experience pertaining to clinical course of patients with intracranial aneurysm requiring placement of FD. Materials and Methods After approval from institute ethics committee (IEC), the authors retrospectively studied all patients who underwent placement of FD for intracranial aneurysms from January 2014 to December 2017. Data regarding patient demographics, presenting complaints, aneurysm details, anesthesia technique, and intra- and postprocedural complications were noted. Duration of hospital stay, neurological outcome as measured by Glasgow outcome scale (GOS) at discharge and at 6 months was noted. Data are presented as median (range) or number (%). Results Over a period of 3 years, 22 patients underwent FD placement. Two patients had subarachnoid hemorrhage (SAH) at the time of presentation, and the rest had unruptured aneurysms. All patients received general anesthesia (GA) for the procedure, and intravenous propofol was used for induction of anesthesia. Majority of the patients received sevoflurane and nitrous oxide combination for maintenance of anesthesia (20/22 [91%]). Five patients were not extubated at the end of the procedure. The most common indication for mechanical ventilation was delayed reversal because of hypothermia. At 6 months of follow-up, GOS was 5 in 18 patients. None of the patients developed any delayed complications related to FD and were neurologically intact. Conclusions The use of FD for the treatment of aneurysms is a safe option. GA was used for carrying out procedure in all patients. The neurological outcome was good in all patients who were followed at 6 months.