Risk factors for postoperative hypoxemia in patients undergoing Stanford type A aortic dissection surgery / 中国医师进修杂志

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.

Finite element method and computational fluid dynamics used in the analysis of a stent / 生物医学工程学杂志

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.

Hemodynamics analysis of intravascular stents with different design features / 生物医学工程学杂志

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