Objective Based on hemodynamic analysis, to investigate the cause of distal re-entry tear in Stanford type B aortic dissection after thoracic endovascular aortic repair (TEVAR).Methods A patient with type B aortic dissection was reexamined regularly with computed tomography angiography (CTA) at 1st month, 6th month, 12th month and 24th month after TEVAR. Based on the CTA images in each period, three-dimensional (3D) aorta models were reconstructed to perform morphological analysis and hemodynamic simulation.Results Compared with the diameter at 1st month after TEVAR, the diameter of true lumen at 12 months after TEVAR increased by 1.8 times and the global distortion of aorta increased by 16.67%. At postoperative 1st, 6th and 12th month, the maximum blood velocities at the new entry tear in systole were 69.6%, 33.7% and 92.1% higher than the average ones at distal landing zone, and the maximum wall shear stresses (WSSs) were 2.52, 2.32 and 3.52 times of the average WSSs respectively. In addition, the maximum time-averaged WSS (TAWSS) at 1st, 6th and 12th month after TEVAR were 1.88, 2.53 and 3.62 times of the mean TAWSS respectively.ConclusionsThe morphology of the aorta remodeled after TEVAR, and a sudden change in the diameter of true lumen occurred at distal anchoring zone and continued to increase. As a result, the blood flow velocity in this area accelerated, and the intima was continuously exposed to high WSS, leading to the redissection.

Objective To study the effects of aneurysmal neck angle on stent displacement after endovascular repair of abdominal aortic aneurysm (AAA). Methods The CT images of 28 patients were selected to establish preoperative AAA model, postoperative AAA model and covered stent model respectively, and the models were divided into non-severe angulation group ( n = 14) and severe angulation group ( n = 14) according to the preoperative angle of tumor neck. The geometric shape of each model was measured, and the changes of AAA geometric parameters and postoperative stent displacements before and after surgery were analyzed. The displacement force of the model during the first follow-up was calculated by hemodynamic simulation. Results Significant differences were found in tumor length, maximum diameter, displacement force, tumor neck length and tumor volume between two groups of patients (P<0. 05), while there was no significant difference between COG (the center of gravity) displacement and proximal displacement (P> 0. 05). For the incidence of internal leakage, there were 2 cases in non-severe angulation group and 4 cases in severe angulation group (P>0. 05).Conclusions Severe neck angulation can lead to a significant increase in support displacement force and decrease in proximal anchorage zone, and thus increase the possibility of support displacement. It is suggested that doctors should strengthen postoperative follow-up for patients with severe neck angulation and be vigilant of the occurrence of long-term internal leakage in clinic.

Objective To study the intestinal absorption characteristics of apixaban in rats with renal failure, and the effect of P-glycoprotein (P-gp) inhibitors on its absorption behavior. Methods The in vivo absorption experiment was performed in CRF rats by one-way perfusion method and the absorption factors was investigated by establishing the HPLC analysis method. Results The absorption rate constant (K_a) of apixaban in each intestinal segment was significantly different (P<0.05) with no significant difference in apparent absorption coefficient (P_app) (P>0.05). The K_a and P_app values in the rat ileum decreased with the increasing of drug concentration. After addition of P-gp inhibitor verapamil hydrochloride (0.1 mmol/L), the K_a and P_app values of apixaban in the jejunum and ileum were significantly increased. Conclusion Apixaban is absorbed in all intestinal segments. P-gp inhibitors can significantly promote the absorption of apixaban in jejunum and ileum, suggesting that apixaban is P-gp substrate and its absorption mechanism is supposed to be active transport.

【Objective】 To explore the effects of prucalopride (PRUC) on the intestinal function during the perioperative period of robot-assisted laparoscopic radical cystectomy (RARC) and urinary diversion. 【Methods】 A total of 75 patients undertaking RARC with urinary diversion (orthotopic neobladder or ileal bladder) in Nanjing Drum Hospital during Jan.and Dec.2021 were divided into PRUC group (n=28) and control group (n=47) according to whether they took PRUC or not.Postoperative intestinal ventilation time and defecation time, drainage tube retention time, tolerance time for first intake of semi-flow food, postoperative hospital stay, and incidence of complications were observed and recorded in the two groups.Postoperative C-reactive protein (CRP) and neutrophil/lymphocyte ratio (NLR) were compared. 【Results】 The PRUC group had shorter intestinal ventilation time and defecation time [(47.14±16.31) h vs.(74.04±35.33) h, P<0.01; (86.14±30.47) h vs.(123.57±79.12) h, P=0.02] , smaller change of ΔCRP and ΔNLR [(79.99±29.71) mg/L vs.(127.75±56.98) mg/L; (9.24±6.43) vs.(16.11±9.90), P<0.01] .All complications were minor, the incidence of intestinal obstruction in PRUC group tended to decrease within 90 days after operation (P=0.38), and there was no significant difference in other complications between the two groups (P>0.05). 【Conclusion】 The perioperative use of PRUC in RARC with urinary diversion is safe and effective, which can promote the recovery of intestinal function after operation.