Unloading and successful treatment with bioresorbable stents during percutaneous coronary intervention:A case report

BACKGROUND With the development of percutaneous coronary intervention(PCI),the number of interventional procedures without implantation,such as bioresorbable stents(BRS)and drug-coated balloons,has increased annually.Metal drug-eluting stent unloading is one of the most common clinical complications.Comparatively,BRS detachment is more concealed and harmful,but has yet to be reported in clinical research.In this study,we report a case of BRS unloading and successful rescue.This is a case of a 59-year-old male with the following medical history:“Type 2 diabetes mellitus”for 2 years,maintained with metformin extended-release tablets,1 g PO BID;“hypertension”for 20 years,with long-term use of metoprolol sustained-release tablets,47.5 mg PO QD;“hyperlipidemia”for 20 years,without regular medication.He was admitted to the emergency department of our hospital due to intermittent chest pain lasting 18 hours,on February 20,2022 at 15:35.Electrocardiogram results showed sinus rhythm,ST-segment elevation in leads I and avL,and poor R-wave progression in leads V1–3.High-sensitivity troponin I level was 4.59 ng/mL,indicating an acute high lateral wall myocardial infarction.The patient’s family requested treatment with BRS,without implanta-tion.During PCI,the BRS became unloaded but was successfully rescued.The patient was followed up for 2 years;he had no episodes of angina pectoris and was in generally good condition.CONCLUSION We describe a case of a 59-year-old male experienced BRS unloading and successful rescue.By analyzing images,the causes of BRS unloading and the treatment plan are discussed to provide insights for BRS release operations.We discuss preventive measures for BRS unloading.

Bioresorbable stent unloading during percutaneous coronary intervention:Early detection and management

In this letter,we comment on a recent case report by Sun et al in the World Journal of Cardiology.The report describes the successful management of a rare complication:The unloading or detachment of a bioresorbable stent(BRS)during percutaneous coronary intervention(PCI)in a male patient.The unloading of BRS was detected via angiography and intravascular ultrasound(IVUS)imaging of the left coronary artery and left anterior descending artery.Although this case is interesting,the authors’report lacked crucial details.Specifically,insufficient information about the type of BRS used,potential causes of BRS unloading,or whether optical coherence tomography(OCT)imaging for coronary arteries was performed before,during,or after PCI.The OCT imaging of coronary arteries before PCI can potentially prevent BRS unloading due to its higher resolution compared to IVUS.In addition,despite detecting myocardial bridging during the PCI,the authors did not provide any details regarding this variation.Here we discuss the various types of BRS,the importance of OCT in PCI,and the clinical relevance of myocardial bridging.

Recognition and management of stent malposition in the portal vein during endoscopic retrograde cholangiopancreatography:A case report

BACKGROUND Portal vein injury is an uncommon complication of endoscopic retrograde cholangiopancreatography(ERCP),for which stent malpositioning in the portal vein is very rare and can lead to fatal events.We report a case of biliary stent migration to the portal vein and a novel method for its safe removal under the guidance of portal angiography.Moreover,we reviewed the literature and summarized reports on the identification and management of this condition.CASE SUMMARY A 59-year-old woman with pancreatic cancer presented with abdominal pain and a high fever 20 days after the placement of two plastic biliary stents under the guidance of ERCP.Blood cultures and laboratory tests revealed sepsis,which was treated with antibiotics.A contrast-enhanced computed tomography scan revealed that one of the biliary stents in the main portal vein was malpositioned.To safely remove the stent,portal angiography was performed to visualize the portal vein and to allow the management of any bleeding.The two stents were removed without obvious bleeding,and an uncovered self-expanding metal stent was placed in the common bile duct for drainage.The patient had an uneventful 6-month follow-up period,except for self-resolving portal vein thrombosis.CONCLUSION The combination of endoscopic and angiographic techniques allowed uneventful management of stent malposition in the portal vein.

Fatigue Performance of Fabrics of Stent-Grafts Supported with Z-Stents vs. Ringed Stents

Stent-grafts were commercialized rapidly and gained a broad clinical acceptance over the past two decades. However,relatively more recent recognition of particular stent-graft design shortcomings have been identified which need to be addressed. It appears that various stent-graft designs may be more or less resistant to metal fatigue and /or fabric abrasions which can lead to type III and type IV endoleaks over the long term. Therefore,it is necessary to investigate the fatigue performance of the most common stentgraft designs: Z-stents and ringed stents,in a long-term in vitro fatigue simulation environment. This paper aimed to analyze nondestructively( gross observations) and destructively( fabric characteristics,mechanical and chemical properties) in order to put forward suggestions to improve the fabric and stent characteristics that may prevent type III and IV endoleaks. The fabric supported with ringed stent-grafts remained nearly completely intact after 168h. However, the fabric supported with Z-stents demonstrated significant damage. Fabric characteristics and tensile strength of the fibers did not present a significant difference between the control and fatigue simulated specimens. The crystallinity declined for both specimens. The fatigue performance of fabrics supported with ringed stents appears to be superior to that supported with Z-stents. The potential for a dynamic and destructive interaction between the apices of Z-stents which can lead to fraying and /or tearing of the graft fabric must be addressed in future designs.

Mechanical compression management of the right middle cerebral artery inferior trunk using a stent during coil embolization of middle cerebral artery aneurysms:A case report and literature review

Endovascular coil embolization is a minimally invasive,rapid,and effective method for the treatment of intracranial aneurysms.However,complications associated with coil embolization,such as intraoperative aneurysm rupture or arterial occlusion,should be promptly managed during the procedure to avoid catastrophic consequences.This study presents a case of mechanical compression management of the right middle cerebral artery(MCA)inferior trunk during coil embolization for bilateral MCA aneurysms.The inferior trunk of the right MCA was abruptly occluded due to mechanical compression during coil embolization of the right MCA bifurcation aneurysm.A Solitaire AB stent(4×20 mm,Covidien/Medtronic,Dublin,Ireland)was implanted in the inferior trunk of the right MCA after tirofiban was injected via a microcatheter,and the right inferior trunk was recanalized.The patient also underwent coil embolization of the left MCA bifurcation aneurysm,without any complications.It is crucial to recognize compressive occlusion of adjacent aneurysm branches to avoid severe complications during intracranial aneurysm embolization.Stent placement is a rescue treatment option for recanalization of an occluded artery.

Monitoring cerebral ischemia during carotid endarterectomy and stenting

Current therapy for carotid stenosis mainly includes carotid endarterectomy and endovascular stenting,which may incur procedure-related cerebral ischemia.Several methods have been employed for monitoring cerebral ischemia during surgery,such as awake neurocognitive assessment,electroencephalography,evoked potentials,transcranial Doppler,carotid stump pressure,and near infrared spectroscopy.However,there is no consensus on the gold standard or the method that is superior to others at present.Keeping patient awake for real time neurocognitive assessment is effective and essential;however,not every surgeon adopts it.In patients under general anesthesia,cerebral ischemia monitoring has to rely on non-awake technologies.The advantageous and disadvantageous properties of each monitoring method are reviewed.

Persistent current in a magnetized Rashba ring

We theoretically study the persistent currents flowing in a Rashba quantum ring subjected to the Rashba spinorbit interaction. By introducing uniform or nonuniform magnetization into the ring, we find that a nonzero persistent charge current circulates in the ring, which stems from the original equilibrium spin current due to the Rashba spinorbit interaction. Because of broken time reversal symmetry, the two oppositely flowing spin-up and spin-down charge currents of the equilibrium spin current are no longer equal, and so a net persistent charge current can flow in the system. It is also found that the persistent current can be modulated by the Fermi energy, the Rashba spin-orbit interaction strength and the magnetization in the ring. Moreover, the magnetization perpendicular to the ring plane can optimize the current. The persistent current flowing in the ring is a manifestation of the nonzero equilibrium spin current existing in the ring.

PERSISTENT CURRENT IN A ONE-DIMENSIONAL MESOSCOPIC RING WITH ELECTRON-PHONON INTERACTION IN THE LATTICE MODEL

A new non-perturbative method is used to discuss the persistent current in a one-dimensional mesoscopic ring threaded by a flux φ with electron-phonon interaction in the lattice model. The current is periodic in φ with a flux quantum φ 0 and the electron-phonon interaction suppresses the persistent current. By considering the contributions of many-phonon correlations, we could obtain more accurate results.

Metallic ureteral stent in restoring kidney function: Nine case reports

BACKGROUND Retroperitoneal fibrosis is an exceptionally rare disease characterized by proliferation of fibrous tissue and inflammation in the retroperitoneum.It features many symptoms in the kidneys and in other organs and usually leads to ureteral obstruction.CASE SUMMARY Here we present 9 consecutive cases of idiopathic retroperitoneal fibrosis(IRPF)in patients who presented to the Department of Nephrology or Department of Rheumatology,Xuanwu Hospital,Capital Medical University,Beijing,China,between January 2012 and June 2017 with ureteral obstruction due to external compression of the ureter that led to hydronephrosis and kidney dysfunction.Computed tomography imaging was used to identify hydronephrosis and ureteral obstruction and to evaluate kidney function.Each patient was diagnosed with IRPF based on clinical observation and computed tomography examination results.To restore kidney function,a retrograde metallic stent was placed in the ureter under X-ray guidance 2 d after each patient’s admission.No perioperative complications occurred in any patient,but postoperative complications occurred in two patients as follows:Patient 2 had stent migration and repeated metallic stent infections that resolved with treatment;and patient 4 had postoperative hematuria because he resumed normal activities too soon after stent placement(contrary to instruction).Placement of the metallic ureteral stents provided relief from ureteral obstruction and restored kidney function in all patients.CONCLUSION Our 9-case series underscores the utility and efficacy of applying the Resonance®metallic ureteral stent to treat ureteral obstruction in patients with IRPF.For all retroperitoneal fibrosis cases in our series,ureteral stents provided effective relief and were shown to reduce the incidence rate of perioperative and postoperative complications.

Persistent fever during treatment of a pregnant woman with acute pyelonephritis

Acute pyelonephritis is a serious infection in pregnancy. It is presented with fever, shaking chills and flank pain. Intravenous hydration and antimicrobial therapy are sufficient in the treatment unless pyelonephritis is complicated. In case of fever persisting for more than 48 h despite appropriate antimicrobial treatment, a possible complication such as urinary tract obstruction, abscess or phlegmon should be considered. Here, we present an 18-year-old pregnant woman with acute pyelonephritis whose persistent fever returned to normal after double-J ureteral stent was placed even if she had no finding of such a complication.

Persistent Current in Two Connected Mesoscopic Rings with Reservoirs

The persistent current and transmission of two connected Aharonov-Bohm rings coupled to external leads are solved analytically. The conditions on which we may observe persistent current, zero or perfect transmission as well as Fano resonance are studied.

Analogue Between Dynamic Hamiltonian-Operators of a Mesoscopic Ring Carrying Persistent Current and a Josephson Junction

By making the analogy between the operator Hamiltonians of a mesoscopic ring carrying the persistent current and a Josephson junction we have introduced a phase operator and entangled state representation to establish a theoretical formalism for the ring system.

Effect of electric field on the spectrum and the persistent current of a quantum ring with two electrons （II） additional effect of a charged impurity

This paper studies the effect of a charged impurity together with or without an external homogeneous electric field on a quantum ring threaded by a magnetic field B and containing two electrons. The potential caused by the impurity has been plotted which is helpful to the understanding of the electronic structures inside the ring. The deep valley appearing in the potential curve is the source of localization, which affects seriously the Aharonov-Bohm oscillation （ABO） of the energy and persistent current. It also causes the fluctuation of the total orbital angular momentum L of the pair of electrons. It is found that the appearance of the impurity reduces the domain of the fractional ABO. During the increase of B, the domain of the integral ABO may appear earlier when B is even quite small. The transition from the localized states to extended states has also been studied. Furthermore, it has deduced a set of related formulae for a transformation, by which an impurity with a charge ep placed at an arbitrary point Rp is equivalent to an impurity with a revised charge ep placed at the X-axis with a revised radial distance Rp. This transformation facilitates the calculation and make the analysis of the physical result clearer.

Effect of electric field on the electronic spectrum and the persistent current of a quantum ring with two electrons

The effect of an electric field E on a narrow quantum ring that contains two electrons and is threaded by a magnetic flux B has been investigated. Localization of the electronic distribution and suppression of the AharonovBohm oscillation （ABO） are found in the two-electron ring, which are similar to those found in a one-electron ring. However, the period of ABO in a two-electron ring is reduced by half compared with that in a one-electron ring. Furthermore, during the variation of B, the persistent current of the ground state may undergo a sudden change in sign. This change is associated with a singlet-triplet transition and has no counterpart in one-electron rings. For a given E, there exists a threshold of energy. When the energy of the excited state exceeds the threshold, the localization would disappear and the ABO would recover. The value of the threshold is proportional to the magnitude of E. Once the threshold is exceeded, the persistent current is much stronger than the current of the ground state at E=0.

Value of temporary stents for the management of perivaterian perforation during endoscopic retrograde cholangiopancreatography

Endoscopic retrograde cholangiopancreatography(ERCP) has become the mainstay of treatment in hepato-pancreato-biliary disease. However, ERCP requires a high level of technical skills and experience in therapeutic endoscopy, there is always a risk of complications. Especially, the perforation per se affects the patient adversely, and the clinical course may lead to a poor prognosis, even with appropriate management. The treatments for ERCPrelated perforation are diverse, depending on the location and mechanism of the bowel perforation and the time of diagnosis. Thus, we reviewed the appropriate surgical and non-surgical management options for therapeutic ERCP-related perforations, especially, evaluating metallic stenting as a treatment modality in perivaterian perforation.

Comparison of postoperative complications between internal and external pancreatic duct stenting during pancreaticoduodenectomy: a meta-analysis

Background：Two types of pancreatic duct stents are used to improve postoperative outcomes of pancreatic anastomosis.The aim of this meta-analysis was to evaluate and compare the postoperative outcomes of patients with internal or external stenting during pancreaticoduodenectomy（PD）.Methods：We searched Pub Med,EMBASE,the Cochrane Library and Web of Science databases until the end of December,2014.Studies comparing outcomes of external vs.internal stent placement in PD were eligible for inclusion.Included literature was extracted and assessed by two independent reviewers.Results：Seven articles were identified for inclusion：three randomized controlled trials（RCTs）and four observational clinical studies（OCS）.The meta-analyses revealed that use of external stents had advantage on reducing the incidences of pancreatic fistula（PF）in total[odds ratio（OR）=0.69;95%confidence interval（CI）,0.48-0.99;P=0.04],PF in soft pancreas（OR=0.30;95%CI,0.16-0.56;P=0.0002）and delayed gastric emptying（DGE）（OR=0.58;95%CI,0.38-0.89;P=0.01）compared with internal stents.There were no significant differences in other postoperative outcomes between two stenting methods,including postoperative morbidity（OR=0.93;95%CI,0.39-2.23;P=0.88）,overall mortality（OR=0.70;95%CI,0.22-2.25;P=0.55）,and intra-abdominal collections（OR=0.67;95%CI,0.26-1.71;P=0.40）.Conclusions：Based upon this meta-analysis,the use of external pancreatic stents might have potential benefit in reducing the incidence of PF and DGE.Due to the limited number of original studies,more RCTs are needed to further support our result and clarify the issue.

Coronary Stents Fracture: An Engineering Approach (Review)

With the invention of coronary stent, promising clinical outcomes appeared. However, the long-term success of stent has been beaten by significant in-stent restenosis and consequently stents fractures (SF). Cardiologists have been looking on SF as a threat to patients’ life because it is associated with short- and possibly long-term morbidity rate. In this review, stent materials and properties from the perspective of materials engineering and clinical drivers are discussed. The review also outlines how stent materials and design have evolved with time. Opinions are given as to the merit and direction of various on-going and future developments.

Mechanical formula for the plastic limit pressure of stent during expansion

The mechanics of cardiovascular stents during the process of expansion are very important for stent function and safety. In general, finite element method （FEM） or experi- ments are major methods used to ascertain mechanical prop- erties of the stent. In this paper, we develop a theoretical model of the tubular stent, derive formulas for the axial forces and moments on the stent end, and propose formu- las for the plastic limit pressure vs. the stent＇s radius during expansion. Examples covering different geometrical param- eters and material parameters are provided, and the plastic limit pressures calculated by FEM and the present method are compared, proving that the present formulas are acceptable and meaningful for the design and innovation of the stent.