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Renal artery stenosis (RAS) and renal complications emerge in some patients after endovascular aneurysm repair (EVAR) to treat abdominal aorta aneurysm (AAA). The mechanisms for the causes of these problems are not clear. We hypothesized that for EVAR patients, lower limb exercise could negatively influence the physiology of the renal artery and the renal function, by decreasing the blood flow velocity and changing the hemodynamics in the renal arteries. To evaluate this hypothesis, pre- and post-operative models of the abdominal aorta were reconstructed based on CT images. The hemodynamic environment was numerically simulated under rest and lower limb exercise conditions. The results revealed that in the renal arteries, lower limb exercise decreased the wall shear stress (WSS), increased the oscillatory shear index (OSI) and increased the relative residence time (RRT). EVAR further enhanced these effects. Because these parameters are related to artery stenosis and atherosclerosis, this preliminary study concluded that lower limb exercise may increase the potential risk of inducing renal artery stenosis and renal complications for AAA patients. This finding could help elucidate the mechanism of renal artery stenosis and renal complications after EVAR and warn us to reconsider the management and nursing care of AAA patients.

BackgroundAbdominal aortic aneurysm (AAA) is a kind of dangerous aortic vascular disease, which is characterized by abdominal aorta partial enlargement. At present, endovascular aneurysm repair (EVAR) is one of the main treatments of abdominal aortic aneurysm. However for some patients after EVAR the aneurysm re-expanded and even ruptured, leading to poor postoperative effect. The stent-graft endoleak after EVAR was realized to influence the AAA in-sac pressure and contribute to the aneurysm re-enlargement.MethodsIn order to analyze the influence of endoleaks positions on the pressure shielding ability of stent-graft after EVAR, type I and type III endoleak models were reconstructed based on computed tomography (CT) scan images, and the hemodynamic environment in AAA was numerically simulated.ResultsWhen the endoleak was at the proximal position the pressure shielding ability will be obviously weakened. While, the pressure shielding ability was higher in the systole phase than that in diastole phase when the endoleak located at the middle or distal positions. Unfortunately, when the endoleak located at the proximal position, the pressure shielding ability would be relatively weak in the whole cardiac cycle.ConclusionsThe results revealed that the influence of endoleaks on pressure shielding ability of stent-graft was both location and time specific.

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The effects of different doses of cisatracurium besilate on perioperative hemodynamics and early postoperative cognitive function in patients undergoing radical resection of lung cancer were investigated. One hundred and thirty-six patients who underwent radical resection of lung cancer from June 2013 to June 2016 in Dongying People's Hospital were retrospectively analyzed. Patients who were not given atracurium were selected as the control group (n=35). According to the different anesthetic doses, patients in the experimental group were separated into low dose (0.15 mg/kg cisatracurium besilate) group (LD group, n=34), medium dose (0.2 mg/kg cisatracurium besilate) group (MD group, n=36) and high dose (0.3 mg/kg cisatracurium besilate) group (HD group, n=31). The mean arterial pressure and heart rate (HR) were recorded before induction of anesthesia (T0), at the time of entering pleural cavity (T1), at the end of surgery (T2), and 1 day after surgery (T3). The Mini-Mental State Examination (MMSE) was used to evaluate the postoperative cognitive function scores of the 4 groups 1 day before operation and on the 1st, 3rd and 7th day after surgery. The agitation of patients at 6 and 12 h after operation was evaluated by Ramsay sedation score. There was no significant difference in arterial pressure among the four groups at T2 and T3 (P>0.05). There was no significant difference in terms of MMSE among the four groups 1 day before operation, 3 days after operation and 7 days after operation, but the MMSE score of the control group was significantly lower than that of the LD, MD and HD groups 1 day after surgery (P<0.05). Therefore, cisatracurium besilate can stabilize hemodynamics during radical operation of lung cancer and reduce the incidence of postoperative cognitive dysfunction, and it has no close association with the dose.