Wall shear stress plays an important role in the development of in-stent restenosis. It has been demonstrated that low wall shear stress. is associated with neointimal hyperplasia. We used computational fluid dynamics (CFD) to investigate the steady and pulsatile flows in the vicinity of model stents and focused on the changes of wall shear stress caused by the implanted stents. The results showed that wall shear stress depended greatly on the size and structure of the stents, which would have implications for the optimization of intravascular
Angioplasty, Balloon, Coronary ; adverse effects ; instrumentation ; Biomechanical Phenomena ; Computer Simulation ; Computer-Aided Design ; Coronary Restenosis ; prevention & control ; Hemodynamics ; physiology ; Humans ; Prosthesis Design ; Shear Strength ; Stents

Abstract: To report a case of Aspergillus salwaensis-induced spinal infection and its laboratory detection. The inflammatory granulation and necrotic tissue samples of a patient with spinal infection were collected from, the Affiliated Hospital of Chengde Medical College on June 17, 2020 for direct smear microscopy and culture, and the isolated strain was identified by microscopy by smear staining, matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF-MS), molecular identification and in vitro antifungal susceptibility test. The patient was 62 years old female and presented with recurrent chest and back pain with no obvious cause. The initial diagnosis was spinal infection, after 7 days of treatment with levofloxacin, the effect was not good. Surgery was then performed remove the lesion via posterior thoracic debridement, and fungal hypha was observed under microscope in tissue specimens. The isolated strains had no typical structure, MALDI-TOF-MS was used for identification for many times, but there was no identification result. After 7 days of fluconazole treatment, the patient's condition improved, and her chest and back pain were alleviated compared to before surgery. The patient was discharged and followed up in the outpatient department, the fungus was later identified as Aspergillus salwaensis by sequence analysis of the internal transcribed spacer (ITS) gene sequencing, and the patient's antifungal medication was changed to voriconazole after with the attending physician. The patient consciously recovered well with no pain in the operative area and normal spinal activity at 1 year follow-up. The possibility of spinal fungal infection should be considered in patients with back pain without a clear cause and poor response to routine antibiotic treatment. Direct smear report of microscopic results are very important for guiding clinical antibiotic selection for rare filament fungi with atypical colony and microscopic morphology and unsuccessful MALDI-TOF-MS identification, molecular biological methods such as ITS sequence analysis can be helpful for early identification of the fungal species, improving identification speed.

Stent implantation can cause thrombus, vessel injury and blood flow disturbance which are considered as the main causes of instent restenosis. In order to investigate the influence of stent implantation on vessel wall and blood flow, we used finite element method (FEM) and computational fluid dynamics (CFD) in this work. The results showed that the implantation of the stent could cause vessel injury and flow stagnation. The instant recoil of the implanted stent is much more than that of the stent itself (12.3% versus 3.1%). In conclusion, FEM and CFD can help illustrate and quantify some biomechanical characteristics for the optimization of stent design.
Blood Flow Velocity ; physiology ; Computer Simulation ; Finite Element Analysis ; Humans ; Models, Cardiovascular ; Prosthesis Design ; Prosthesis Implantation ; methods ; Stents ; adverse effects

Objective To explore the risk factors for postoperative hypoxemia in patients undergoing Stanford type A aortic dissection surgery.Methods The clinical data of 77 patients with Stanford type A aortic dissection surgery were analyzed retrospectively.Among the patients, 40 patients occurred hypoxemia(hypoxemia group),and 37 patients did not occur hypoxemia(non-hypoxemia group).The preoperative,intraoperative and postoperative clinical data were compared between 2 groups,and the independent risk factors for postoperative hypoxemia were analyzed by multiple Logistic regression analysis.Results The incidence of postoperative hypoxemia in patients with Stanford type A aortic dissection was 51.9% (40/77).The multiple Logistic regression analysis result showed that age (OR =1.088,95% CI 1.018-1.164,P=0.013),body mass index≥25 kg/m2(OR=6.495,95% CI 1.327-31.789,P=0.021),pericardial effusion(OR=6.384,95% CI 1.426-28.576,P=0.015),white blood cell count(OR=1.289,95% CI 1.033-1.609,P=0.024)and using recombinant human coagulationⅦa (OR = 23.757, 95% CI 2.849 - 198.085, P = 0.003) were the independent predictive factors for postoperative hypoxemia in patients with Stanford type A aortic dissection.Conclusions The postoperative hypoxemia in patients with Stanford type A aortic dissection is related with perioperative systemic inflammation, especially in obese patients who should be given anti-inflammatory treatment during perioperative period.Control of bleeding and reducing the recombinant human coagulationⅦa as far as possible can reduce the incidence of postoperative hypoxemia.