Stent Failure Research Articles

Association of stroke or death with severity of carotid lesion calcification in patients undergoing carotid artery stenting

ObjectiveCarotid artery stenting (CAS) for heavily calcified lesions is controversial due to concern for stent failure and increased perioperative stroke risk. However, the degree to which calcification affects outcomes is poorly understood, particularly in transcarotid artery revascularization (TCAR). With the precipitous increase in TCAR use and its expansion to standard surgical-risk patients, we aimed to determine the impact of lesion calcification on CAS outcomes to ensure its safe and appropriate use. MethodsWe identified patients in the Vascular Quality Initiative who underwent first-time transfemoral CAS (tfCAS) and TCAR between 2016 and 2021. Patients were stratified into groups based on degree of lesion calcification: no calcification, 1% to 50% calcification, 51% to 99% calcification, and 100% circumferential calcification or intraluminal protrusion. Outcomes included in-hospital and 1-year composite stroke/death, as well as individual stroke, death, and myocardial infarction outcomes. Logistic regression was used to evaluate associations between degree of calcification and these outcomes. ResultsAmong 21,860 patients undergoing CAS, 28% patients had no calcification, 34% had 1% to 50% calcification, 35% had 51% to 99% calcification, and 3% had 100% circumferential calcification/protrusion. Patients with 51% to 99% and circumferential calcification/protrusion had higher odds of in-hospital stroke/death (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.02-1.6; P = .034; OR, 1.9; 95% CI, 1.1-2.9; P = .004, respectively) compared with those with no calcification. Circumferential calcification was also associated with increased risk for in-hospital myocardial infarction (OR, 3.5; 95% CI, 1.5-8.0; P = .003). In tfCAS patients, only circumferential calcification/protrusion was associated with higher in-hospital stroke/death odds (OR, 2.0; 95% CI, 1.2-3.4; P = .013), whereas for TCAR patients, 51% to 99% calcification was associated with increased odds of in-hospital stroke/death (OR, 1.5; 95% CI, 1.1-2.2; P = .025). At 1 year, circumferential calcification/protrusion was associated with higher odds of ipsilateral stroke/death (12.4% vs 6.6%; hazard ratio, 1.64; P = .002). ConclusionsAmong patients undergoing CAS, there is an increased risk of in-hospital stroke/death for lesions with >50% calcification or circumferential/protruding plaques. Increasing severity of carotid lesion calcification is a significant risk factor for stroke/death in patients undergoing CAS, regardless of approach.

In silico fatigue optimization of TAVR stent designs with physiological motion in a beating heart model

Background and ObjectiveThe rapid expansion of TAVR to younger, low-risk patients raises concerns regarding device durability. Necessarily, extended stent lifetime will become more critical for new generation devices. In vitro methods commonly used for TAVR stent fatigue testing exclude the effects of the beating heart. We present a more realistic in silico stent fatigue analysis utilizing a beating heart model in which TAVR stents experience complex, nonuniform dynamic loading. MethodsVirtual TAVR deployments were simulated in the SIMULIA Living Heart Human Model of a beating heart using stent models of the self-expandable nitinol 26-mm CoreValve and Evolut R devices, and a 27-mm PolyV-2. Stent deformation was monitored over three cardiac cycles, and fatigue resistance was evaluated for the nitinol stents using finite element analysis via ABAQUS/Explicit. The average strain and strain amplitude of each stent element were tracked, and established thresholds were applied to determine potential fatigue failure. Fatigue performance of control stents was compared to parametrically modified models with a 20% increase or decrease in strut width. ResultsStents with reduced strut width applied lower radial force against the contracting myocardium of the beating heart, resulting in larger displacements and higher strain values. Formulas relating in vivo strain to stent design do not account for this. In all models, there were elements in which strains exceeded fatigue failure. The PolyV-2 stent had far fewer failing elements since its struts were optimized to reduce the strain in stent joints, achieving better fatigue resistance in the stent crown and waist elements. Different stent sections showed markedly different fatigue resistance due to the varying loading conditions. ConclusionsOur analysis indicates that previous studies underestimate strain amplitudes that may cause stent failure. This study demonstrates the utility of advanced in silico analysis of devices deployed within a beating heart that mimics in vivo loading, offering a cost-effective alternative to human or animal trials and establishing a platform to assess the impact of device design on device durability. The limited fatigue life of TAVR stents indicated here highlights a clinical complication that may eventually develop as younger, lower-risk TAVR patients, age.

Procedural and clinical impact of intravascular lithotripsy for the treatment of peri-stent calcification

BackgroundUse of intravascular lithotripsy (IVL) for treating peri-stent calcification is increasing. However, this indication remains ‘off-label’. We aimed to investigate the efficacy and clinical outcomes of in-stent IVL. MethodsPatients from five European centers who underwent in-stent IVL were included between 2019 and 2023. Demographic, clinical, procedural and follow-up data were collected from electronic hospital records. Angiographic and intracoronary imaging (ICI) data were analyzed in a centralized core-laboratory. ResultsOf 101 patients (71.2 ± 9.2 years), 56(55 %) received in-stent IVL for late stent failure (median 109 days post-PCI) due to calcific neoatherosclerosis or extra-stent calcification(late-IVL), while 45(45 %) underwent bail-out IVL due to stent infraexpasion (immediate-IVL). Both late-IVL and immediate-IVL significantly improved angiographic %diameter stenosis (73.7[59.6–89.8]% to 16.4 [10.4–26.9]%;p < 0.0001 and 28.6[22.5–43.3]% to 14.1[10.3–29.4]%;p < 0.0001, and minimum lumen area (MLA) (3.4 ± 1.2 to 8.6 ± 2.5 mm2;p < 0.002 and 5.4 ± 1.9 to 7.3 ± 1.9;p < 0.0001).Device(98 %) and procedural success(80 %) were high. MACE rates in-hospital (2 %), 30-days (3 %),6-months(5 %) and 1-year(7 %) were low and comparable in both groups. Acute diameter gain was lower in immediate-IVL (2.1 ± 0.7 mm vs. 0.5 ± 0.4 mm;p < 0.0001). This, however, was explained by significant differences in pre-IVL angiographic and ICI parameters (%diameter stenosis 73.7[59.6–89.8] vs. 28.6[22.5–43.3]%; p < 0.0001 and MLA (3.4 ± 1.2 vs 5.4 ± 1.9 mm2; p < 0.0001), whereas post-IVL percentage diameter stenosis (16.4(10.4–26.9) vs. 14.1(10.3–29.4);p = 0.914) and MLA (8.6 ± 2.5vs. 7.4 ± 1.9 mm2;p = 0.064) in late- and immediate-IVL were comparable. ConclusionsIVL in-stent due to peri-stent calcification is an effective strategy, both late and immediately after stent implantation. Overall, MACE rates at short- and mid-term were low and comparable in both groups, although clinical findings should be taken with caution.

Preoperative endoscopic biliary drainage by metal versus plastic stents for resectable perihilar cholangiocarcinoma

Background and study aimsAdequate preoperative biliary drainage (PBD) is recommended in most patients with resectable perihilar cholangiocarcinoma (pCCA). Most expert centers use endoscopic plastic stents rather than self-expanding metal stents (SEMS). In the palliative setting, however, use of SEMS has shown longer patency and superior survival. The aim of this retrospective study was to compare stent dysfunction of SEMS versus plastic stents for PBD in resectable pCCA patients. Patients and methodsIn this retrospective, multicenter, international cohort study, patients with a potentially resectable pCCA who underwent initial endoscopic PBD were included from 2010-2020. Stent failure was a composite endpoint of cholangitis and/or re-intervention due to adverse events or insufficient PBD. Other adverse events, surgical outcomes, and survival were recorded. Propensity score matching (PSM) was performed on several baseline characteristics. Results474 patients had successful stent placement, of whom 61 received SEMS and 413 plastic stents. PSM (1:1) resulted in two groups of 59 patients. Stent failure occurred significantly less in the SEMS group (31% vs 64%, p<0.001). Besides less cholangitis after SEMS placement (15% vs 31%, p = 0.012), other PBD-related adverse events did not differ. The number of patients undergoing surgical resection was not significantly different (46% vs 49%, p = 0.71). Complete intraoperative SEMS removal was successful and without adverse events in all patients. ConclusionsStent failure was lower in patients with SEMS as PBD compared to plastic stents in patients with resectable pCCA. Removal during surgery was well feasible. Surgical outcomes were comparable.

Case report and narrative review of the literature: a rare colonic stent failure in a palliative patient

IntroductionWith palliative patients, a holistic approach is important. Interventions should minimise length of hospital stay, maximise quality of life, and control symptoms. A self-expanding metal stent (SEMS) for the palliative treatment of malignant large bowel obstruction (MLBO) is designed to provide these benefits to patients approaching the end of their life. We present the case of a patient treated with a SEMS over 2 years earlier for MLBO. He was treated with palliative intent at diagnosis because his frailty and medical co-morbidities precluded surgery. He later presented with severe tenesmus, and these new symptoms were later found to be due to a rare stent failure in which the stent had fractured and was irretrievable. This had to be managed conservatively before the patient sadly passed away 7 months later.DiscussionA SEMS is considered the first-line treatment to relieve MLBO caused by inoperable left-sided colonic cancer. This treatment offers a reduced length of hospital stay, reduced stoma rates, fewer complications, and comparable survival compared to de-functioning stoma. However, SEMSs are not expected to be in use for extended periods of time. The literature reports an average survival after a colonic stent insertion of between 121 and 199 days when used in a palliative setting.ConclusionThis is one of the first case reports to describe a colonic stent failure occurring over 2 years after insertion. This case argues that further research into the longer-term outcomes of this management option is warranted, particularly as palliative patients are living longer.

Association of LDL-C level with neoatherosclerosis and plaque vulnerability in patients with late restenosis: an optical coherence tomography study

Neoatherosclerosis (NA) is a significant contributor to late stent failure; however, predictors of late in-stent restenosis (ISR) with NA have not been systematically reported. This study aimed to identify predictors of NA incidence and plaque vulnerability in patients with late ISR and the role of low-density lipoprotein cholesterol (LDL-C) levels in this process. A total of 216 patients with 216 lesions who underwent optical coherence tomography (OCT) before interventional procedure for late drug-eluting stent ISR were enrolled and divided into NA and non-NA groups based on OCT findings. Results showed that higher LDL-C levels were associated with NA, thin-cap fibroatheroma (TCFA), intimal disruption, plaque erosion, and thrombosis. Multivariate regression analysis revealed that the LDL-C level was an independent risk factor for NA and TCFA. The LDL-C levels exhibited a significant predictive value for NA and TCFA, surpassing other factors such as stent age and other lipid types. In conclusion, a high LDL-C level is an independent predictor of NA incidence and plaque vulnerability in patients with late ISR.

Corrosion failure of nitinol stents in the upper gastrointestinal tract: The role of surface finishes and the importance of an appropriate test environment

Esophageal nitinol stents are an established method for treating swallowing difficulties caused by obstructing cancer. As a consequence of improved patient survival, stent failure and an increasing need for re-intervention is a rapidly emerging problem. This research investigates the influence of different quality of raw metal alloys in combination with production technology on corrosion resistance. Four different international stent manufacturers produced samples of their standard stents from nitinol sourced from three different alloy manufacturers. The corrosion resistance was evaluated by cyclic potentiodynamic scans according to the ASTM standards in phosphate buffered saline solution. Because of targeted application of the stent in gastrointestinal tract, the simulated gastric fluid was also used for corrosion measurement. In addition, the surface of the samples was studied by X-ray Photoelectron Spectroscopy and Mott-Schottky analysis. Results demonstrated that both, raw material and certain steps in the manufacturing process affects corrosion resistance. Conversely, other certain measures in the manufacturing process are able to reduce the impact of the base material on corrosion susceptibility. Furthermore, we could demonstrate that a key factor influencing corrosion resistance is the concentration of nickel on the surface. Current accepted standard test methods with phosphate buffered saline solution are inadequate for assessing susceptibility to corrosion by gastric acid and should take the low pH of the implanted environment into account. Understanding the corrosive process and the impact of surface finishes is key to developing stents suitable for long-term palliation.

Pancreaticoduodenal Artery Aneurysm Complicated by Median Arcuate Ligament Syndrome.

To highlight median arcuate ligament syndrome as a potential cause for celiac artery stenosis and pancreaticoduodenal artery aneurysm, and describe treatment options in this setting. A 63-year-old male presented with a pancreaticoduodenal artery aneurysm and concomitant celiac artery stenosis that was treated with celiac artery stenting and aneurysm coiling. He subsequently developed stent fracture and celiac artery occlusion secondary to previously unrecognized median arcuate ligament syndrome causing reperfusion of the aneurysm. This was treated with open median arcuate ligament release and aorta to common hepatic artery bypass with good clinical result and stable 20-month surveillance imaging. It is critical to recognize median arcuate ligament syndrome as a cause of celiac artery stenosis in the setting of pancreaticoduodenal artery aneurysm given the high risk of failure of endovascular stenting. Open aorto-hepatic artery bypass and endovascular aneurysm coiling should be the preferred approach in these patients.

Impact of Stent Expansion Index on Stent Failure After Left Main Stenting

Impact of the stent expansion index (EXPI) in percutaneous coronary intervention (PCI) for unprotected left main distal bifurcation lesions (ULMD) has been not completely understood especially in current-generation drug-eluting stent (cDES) era. We evaluated the impact of EXPI on clinical outcomes after PCI with cDES for ULMD. We identified 342 patients treated with cDES for ULMD and postintervention intravascular ultrasound between January 2010 and December 2019. In this study, the ratio of minimum stent area (MSA) to reference vessel area at the MSA site was adopted to assess the stent expansion. We defined the patients with the first and second tertile as low-intermediate EXPI group and those with the third tertile as high EXPI group and compared the clinical outcomes between both groups. The primary end point was target lesion failure (TLF). TLF was defined as a composite of cardiac death, target lesion revascularization (TLR) ,and myocardial infarction. The MSA was located in the ostium of left anterior descending coronary artery in most cases (318 of 342 patients; 93.0%). There were no significant differences between both groups in the baseline clinical, lesion, and procedural characteristics. The high EXPI group had lower TLF rate than the low-intermediate EXPI group (10.2% vs 19.9%, log-rank p=0.033). In conclusion, this is the first report that the higher ratio of MSA to reference vessel area at the MSA site, which was defined as stent EXPI, was associated with more favorable clinical outcomes after PCI for ULMD.

Clinical outcomes of coronary intravascular lithotripsy in patients with stent failure (COIL registry)

BackgroundIntravascular lithotripsy (IVL) has been demonstrated to be an effective treatment of calcified de novo coronary lesions. Safety data on the use of IVL within stented segments are lacking. We sought to evaluate the safety, feasibility, and long-term outcomes of IVL in patients with stent failure. MethodsThis was a retrospective multi-centre registry that included consecutive patients with stent failure who had undergone IVL treatment. The primary efficacy endpoint was procedural success defined as residual stenosis <30% (determined by quantitative coronary angiography analysis) in patients who survived hospital admission without in-hospital adverse events. Major adverse cardiovascular events (MACE) were defined as the composite endpoints of cardiovascular death, spontaneous myocardial infarction, and target vessel revascularisation at one-year follow up. Results102 patients were included in this study. Mean age was 73 ± 9 years and 81% were male. The duration from previous stent implantation and IVL treatment was 24 (interquartile range 7–76) months, of which 10.8% received IVL for acute under-expanded stent. IVL treatment allowed significant improvement in both minimal lumen diameter (1.14 ± 0.60 to 2.53 ± 0.59, P < 0.001) and degree of stenosis (66.8 ± 19.9 to 20.3 ± 11.3%, P < 0.001). The rate of procedural success was 78.4% (80/102 of patients). The one-year MACE was 15.7%. Ostial disease (HR 5.16; 95% CI 1.19 to 22.33; P = 0.028) and lesion length (HR 1.05; 95% CI 1.01 to 1.10; P = 0.010) were independently associated with one-year MACE. ConclusionsIn patients with stent failure, IVL is a safe and feasible treatment for this high-risk group.

Poor Below Knee Runoff Impacts Femoropopliteal Stent Failure and Fluoropolymer Antithrombotic Effect in Healthy Swine Model

Poor below knee (BTK) runoff is a predictor of stent failure after endovascular femoropopliteal artery treatment; however, lack of pathological evaluation has prevented characterisation of stent failure. The study aimed to investigate the impact of poor BTK runoff and the antithrombotic effect of the polymer of fluoropolymer coated paclitaxel eluting stents (FP-PESs) in a healthy swine femoropopliteal artery model. FP-PESs and bare metal stents (BMSs) and FP-PES and polymer free paclitaxel coated stents (PF-PCSs) were implanted in the bilateral femoral arteries of healthy swine (n= 6, respectively) following coil embolisation in both tibial arteries to induce poor BTK runoff. Histological assessment and intravascular imaging device evaluation were performed at one month. The Japanese Association for Laboratory Animal Science approved the study protocol (reference number: IVT22-90). Optical coherence tomography showed significantly lower percent area stenosis in FP-PES compared with BMS (37.3%, [interquartile range (IQR), 25.6-54.3] % vs. 92.5%[IQR, 75.5 - 96.1] %, respectively, p= .031), and PF-PCS (8.3%[IQR, 4.5 - 27.0] % vs. 31.2%[IQR, 23.3 - 52.2] %, respectively, p= .031). Histopathological evaluation demonstrated that thin fibrin attachment without re-stenosis was the most dominant neointimal tissue characteristic in FP-PES. On the other hand, neointimal tissue characteristics with significant restenosis of BMS and PF-PCS were mainly organising or organised thrombus. Organising and or organised thrombus attachment due to poor BTK runoff was the main cause of in stent restenosis of the swine femoral artery. FP-PES demonstrated the least percent area stenosis, suggesting the importance of the antithrombotic effect of polymer.

Current Management of Highly Calcified Coronary Lesions: An Overview of the Current Status.

The amount of coronary calcium strongly correlates with the degree of atherosclerosis and, therefore, with the rate of future cardiac events. Calcified coronary lesions still represent a challenge for interventional cardiologists, bringing not only a higher risk of immediate complications during percutaneous coronary interventions (PCI), but also a higher risk of late stent failure due to under-expansion and/or malapposition, and therefore, have a relevant prognostic impact. Accurate identification of the calcified plaques together with the analysis of their distribution pattern within the vessel wall by intracoronary imaging is important to improve the successful treatment of these lesions. The aim of this review is to guide readers through the assessment of the calcified plaque distribution using intracoronary imaging in order to select the best devices and strategies for plaque debulking and lesion preparation.

WallFlex® and Evolution® Duodenal Stents Have Similar Efficacy but Different Safety for Malignant Gastric Outlet Obstruction.

The WallFlex® and Evolution® stents are the most widely used duodenal stents, but no study has compared them. We aimed to compare the efficacy and safety of WallFlex® and Evolution® stents for malignant gastric outlet obstruction. We included all consecutive patients who were treated for malignant gastric outlet obstruction with WallFlex® or Evolution® self-expandable metal uncovered duodenal stents between 2013 and 2020. Multivariable Cox models were performed to assess duodenal stent failure, as defined by gastric outlet obstruction necessitating another duodenal stent. We included 129 patients: 74 received a WallFlex® stent and 55 received an Evolution® stent. The non-failure rate was of 68% (95%CI 55-84) and 65% (95%CI 50-84) at 6months and of 48% (95%CI 32-73) and 45% (95%CI 27-74) at 1 year, with the WallFlex® and Evolution® stents, respectively. The median time to duodenal stent failure was 10.5months in the WallFlex® group and 9.3months in the Evolution® group. The type of duodenal stent was not associated with duodenal stent failure (p logrank = 0.43, adjusted hazard ratio 1.55; 95%CI 0.77-3.14). The overall survival was similar between the two groups (p logrank = 0.92). Three patients had complications due to Evolution® stents; it consisted in dismantled stents that led to hemorrhage in one patient. WallFlex® and Evolution® duodenal stents had similar efficacy for malignant gastric outlet obstruction. There were more adverse events with Evolution® stents.

Clinical impact of OCT-derived suboptimal stent implantation parameters and definitions.

Despite growing evidence supporting the clinical utility of optical coherence tomography (OCT) guidance during percutaneous coronary interventions (PCIs), there is no common agreement as to the optimal stent implantation parameters that enhance clinical outcome. We retrospectively examined the predictive accuracy of suboptimal stent implantation definitions proposed from the CLI-OPCI II, ILUMIEN-IV OPTIMAL PCI, and FORZA studies for the long-term risk of device-oriented cardiovascular events (DoCE) in the population of large all-comers CLI-OPCI project. A total of 1020 patients undergoing OCT-guided drug-eluting stent implantation in the CLI-OPCI registry with a median follow-up of 809 (quartiles 414-1376) days constituted the study population. According to CLI-OPCI II, ILUMIEN-IV OPTIMAL PCI, and FORZA criteria, the incidence of suboptimal stent implantation was 31.8%, 58.1%, and 57.8%, respectively. By multivariable Cox analysis, suboptimal stent implantation criteria from the CLI-OPCI II [hazard ratio 2.75 (95% confidence interval 1.88-4.02), P < 0.001] and ILUMIEN-IV OPTIMAL PCI [1.79 (1.18-2.71), P = 0.006] studies, but not FORZA trial [1.11 (0.75-1.63), P = 0.597], were predictive of DoCE. At long-term follow-up, stent edge disease with minimum lumen area <4.5 mm2 [8.17 (5.32-12.53), P < 0.001], stent edge dissection [2.38 (1.33-4.27), P = 0.004], and minimum stent area <4.5 mm2 [1.68 (1.13-2.51), P = 0.011] were the main OCT predictors of DoCE. The clinical utility of OCT-guided PCI might depend on the metrics adopted to define suboptimal stent implantation. Uncovered disease at the stent border, stent edge dissection, and minimum stent area <4.5 mm2 were the strongest OCT associates of stent failure.

Fatigue strength and life prediction of lower limb venous stents under three-stage loading conditions

After the implantation of lower limb artery stents, the complex loading conditions imposed on the limb can lead to fatigue failure, which may induce inflammation and restenosis. To investigate the effect of multi-axial loading conditions on the fatigue performance of stents, five stents, namely APsolute Pro (APbott Vascular, USA), Complete SE (Medtronic, USA), Protégé EverFlex (PE3, USA), Pulsar-35 (Biotronik, Germany), and E-luminexx-B (Bard, USA), were analyzed based on the finite element method (FEM). Besides, their fatigue strength was determined under three levels of loading conditions, including tension-bending-torsion and compression-bending-torsion. Based on that, the fatigue life of these stents was predicted. The results showed that based on the nominal stress method, tension-bending-torsion loading had a more significant impact on the fatigue life of stents than compression-bending-torsion loading. Besides, two different types of initial cracks were analyzed by the fracture mechanics method. The results suggested that both the initial crack and the external load were the main causes of stent fatigue fractures. Compared with the loading nature, the influence of the initial crack on stent fatigue life was more significant. Under the same loading condition, the APsolute Pro stent had the longest fatigue life, while the E-luminexx-B stent had the shortest. Moreover, the mechanism of stent fatigue failure was revealed by exploring the fatigue performance and life prediction of stents under complex loading conditions. These findings have important implications for improving the structural design of stents and their clinical selection.

Overexpression of LOX-1 in hepatocytes protects vascular smooth muscle cells from phenotype transformation and wire injury induced carotid neoatherosclerosis through ALOX15

Neoatherosclerosis (NA), the main pathological basis of late stent failure, is the main limitation of interventional therapy. However, the specific pathogenesis and treatment remain unclear. In vivo, NA model was established by carotid wire injury and high-fat feeding in ApoE−/− mice. Oxidized low-density lipoprotein receptor-1/lectin-like oxidized low-density lipoprotein receptor-1 (OLR1/LOX-1), a specific receptor for oxidized low-density lipoprotein (ox-LDL), was specifically ectopically overexpressed in hepatocytes by portal vein injection of adeno-associated serotype 8 (AAV8)-thyroid binding globulin (TBG)-Olr1 and the protective effect against NA was examined. In vitro, LOX-1 was overexpressed on HHL5 using lentivirus (LV)-OLR1 and the vascular smooth muscle cells (VSMCs)-HHL5 indirect co-culture system was established to examine its protective effect on VSMCs and the molecular mechanism. Functionally, we found that specific ectopic overexpression of LOX-1 by hepatocytes competitively engulfed and metabolized ox-LDL, alleviating its resulting phenotypic transformation of VSMCs including migration, downregulation of contractile shape markers (smooth muscle α-actin (SMαA) and smooth muscle-22α (SM22α)), and upregulation of proliferative/migratory shape markers (osteopontin (OPN) and Vimentin) as well as foaminess and apoptosis, thereby alleviating NA, which independent of low-density lipoprotein (LDL) lowering treatment (evolocumab, a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9)). Mechanistically, we found that overexpression of LOX-1 in hepatocytes competitively engulfed and metabolized ox-LDL through upregulation of arachidonate-15-lipoxygenase (ALOX15), which further upregulated scavenger receptor class B type I (SRBI) and ATP-binding cassette transporter A1 (ABCA1). In conclusion, the overexpression of LOX-1 in liver protects VSMCs from phenotypic transformation and wire injury induced carotid neoatherosclerosis through ALOX15.

Evaluation and management of drug-eluting stent in-stent restenosis.

In-stent restenosis (ISR) is the most common cause of stent failure. Although the rate of ISR is significantly lower with contemporary drug-eluting stents (DES), it remains a challenging clinical entity to treat. In this review, we focus on a practical approach to management of DES ISR with intravascular imaging at its core, as supported by several recently published articles. This facilitates assessment of the underlying mechanism(s) essential to the successful treatment of ISR allowing for a tailored selection of treatment modalities. The successful treatment of DES ISR requires identification of the causative mechanism(s). Individualized treatment may include high-pressure balloon angioplasty alone, cutting or scoring balloons, intravascular lithotripsy, atheroablative therapies and a selection of either repeat DES implantation or drug-coated balloon treatment.

SCAI Expert Consensus Statement on Management of In-Stent Restenosis and Stent Thrombosis.

Stent failure remains the major drawback to the use of coronary stents as a revascularization strategy. Recent advances in imaging have substantially improved our understanding of the mechanisms underlying these occurrences, which have in common numerous clinical risk factors and mechanical elements at the time of stent implantation. In-stent restenosis remains a common clinical problem despite numerous improvements in-stent design and polymer coatings over the past 2 decades. It generates significant health care cost and is associated with an increased risk of death and rehospitalization. Stent thrombosis causes abrupt closure of the stented artery and therefore carries a high risk of myocardial infarction and death. This Society for Cardiovascular Angiography & Interventions (SCAI) Expert Consensus Statement suggests updated practical algorithmic approaches to in-stent restenosis and stent thrombosis. A pragmatic outline of assessment and management of patients presenting with stent failure is presented. A new SCAI classification that is time-sensitive with mechanistic implications of in-stent restenosis is proposed. Emphasis is placed on frequent use of intracoronary imaging and assessment of timing to determine the precise etiology because that information is crucial to guide selection of the best treatment option. SCAI recommends image-guided coronary stenting at the time of initial implantation to minimize the occurrence of stent failure. When in-stent restenosis and stent thrombosis are encountered, imaging should be strongly considered to optimize the subsequent approach.

Effect of ureteral stent length and implantation position on migration after implantation.

Ureteral obstruction is a urinary system disease that causes urinary retention, renal injury, renal colic, and infection. Ureteral stents are often used for conservative treatment in clinics, and their migration usually results in ureteral stent failure. The migrations include proximal migration to the kidney side and distal migration to the bladder side, but the biomechanism of stent migration is still unknown. Finite element models of stents with lengths from 6-30cm were developed. The stents were implanted into the middle of the ureter to analyze the effect of stent length on its migration, and the effect of stent implantation position on 6-cm-long stent migration was also observed. The stents' maximum axial displacement was used to assess the ease of stent migration. A time-varying pressure was applied to the ureter outer wall to simulate peristalsis. The stent and ureter adopted friction contact conditions. The two ends of the ureter were fixed. The radial displacement of the ureter was used to evaluate the effect of the stent on peristalsis. The maximum migration occurs in the positive direction for a 6-cm-long stent implanted at the proximal ureter (CD and DE), but in the negative direction at the distal ureter (FG and GH). The 6-cm-long stent demonstrated almost no effect on ureteral peristalsis. The 12-cm-long stent diminished the radial displacement of the ureter from 3-5s. The 18-cm stent diminished the radial displacement of the ureter from 0-8s, and the radial displacement within 2-6s was weaker than other time. The 24-cm stent diminished the radial displacement of the ureter from 0-8s, and the radial displacement within 1-7s was weaker than other time. The biomechanism of stent migration and ureteral peristalsis weakening after stent implantation was explored. Shorter stents were more likely to migrate. The implantation position had less influence on ureteral peristalsis compared with the stent length, which provided a reference for stent design aimed at reducing stent migration. Stent length was the main factor affecting ureteral peristalsis. This study provides a reference for the study of ureteral peristalsis.

Optical coherence tomography-derived predictors of stent expansion in calcified lesions.

Severe coronary artery calcification is associated with stent underexpansion and subsequent stent failure. We aimed to identify optical coherence tomography (OCT)-derived predictors of absolute (minimal stent area [MSA]) and relative stent expansion in calcified lesions. This retrospective cohort study included patients who underwent percutaneous coronary intervention (PCI) with OCT assessment before and after stent implantation between May 2008 and April 2022. Pre-PCI OCT was used to assess calcium burden and post-PCI OCT was used to assess absolute and relative stent expansion. A total of 361 lesions in 336 patients were analyzed. Target lesion calcification (defined as OCT-detected maximum calcium angle ≥ 30°) was present in 242 (67.0%) lesions. Following PCI, median MSA was 5.37 mm2 in calcified lesions and 6.24 mm2 in noncalcified lesions (p < 0.001). Median stent expansion was 78% in calcified lesions and 83% in noncalcified lesions (p = 0.325). In the subset of calcified lesions, average stent diameter, preprocedural minimal lumen area, and total calcium length were independent predictors of MSA in multivariable analysis (mean difference 2.69 mm2 /mm2 , 0.52 mm2 /mm, and -0.28 mm2 /5 mm, respectively, all p < 0.001). Total stent length was the only independent predictor of relative stent expansion (mean difference -0.465% per mm, p < 0.001). Calcium angle, thickness, and the presence of nodular calcification were not significantly associated with MSA or stent expansion in multivariable analyses. Calcium length appeared to be the most important OCT-derived predictor of MSA, whereas stent expansion was mainly determined by total stent length.