Objective To study the influence of stent and balloon shape on hemodynamics in tapered vessels with multiple stenosis.Methods The hemodynamic model was established after the implantation of vascular stent in tapered vessel with multiple stenosis.The numerical simulation method was used to study the effect of the combination of different shaped stents and balloons on postoperative hemodynamics.Results When the cylindrical stent was expanded using the cylindrical balloon and tapered balloon respectively,compared with cylindrical balloon expansion,the proportion of low-speed blood flow area generated by tapered balloon expansion was reduced by 0.58％,and the proportion of low time-averaged wall shear stress(TAWSS)area was reduced by 3.22％.The use of tapered balloon for expansion could produce less low-speed blood flow and low TAWSS area.When tapered balloon was used to expand the cylindrical stent and tapered stent respectively,compared with expanding tapered stent,the proportion of low-speed blood flow area generated by expanding cylindrical stent decreased by 1.35％,and the proportion of low TAWSS area decreased by 9.73％.Conclusions The hemodynamic environment of tapered vessel with multiple stenosis was influenced by the shape of stent and balloon.The use of tapered balloon to expand the cylindrical stent in tapered vessels with multiple stenosis can achieve favorable hemodynamic environment and reduce the risk of ISR occurence.This study can provide a scientific basis for the rational formulation of clinical intervention scheme.

Objective To study the influence of stent and balloon shape on hemodynamics in tapered vessels with multiple stenosis.Methods The hemodynamic model was established after the implantation of vascular stent in tapered vessel with multiple stenosis.The numerical simulation method was used to study the effect of the combination of different shaped stents and balloons on postoperative hemodynamics.Results When the cylindrical stent was expanded using the cylindrical balloon and tapered balloon respectively,compared with cylindrical balloon expansion,the proportion of low-speed blood flow area generated by tapered balloon expansion was reduced by 0.58％,and the proportion of low time-averaged wall shear stress(TAWSS)area was reduced by 3.22％.The use of tapered balloon for expansion could produce less low-speed blood flow and low TAWSS area.When tapered balloon was used to expand the cylindrical stent and tapered stent respectively,compared with expanding tapered stent,the proportion of low-speed blood flow area generated by expanding cylindrical stent decreased by 1.35％,and the proportion of low TAWSS area decreased by 9.73％.Conclusions The hemodynamic environment of tapered vessel with multiple stenosis was influenced by the shape of stent and balloon.The use of tapered balloon to expand the cylindrical stent in tapered vessels with multiple stenosis can achieve favorable hemodynamic environment and reduce the risk of ISR occurence.This study can provide a scientific basis for the rational formulation of clinical intervention scheme.

Objective:To perform a prospective cohort study to identify individual susceptibility of glucocorticoid (GC) -associated osteonecrosis of the femoral head (GA-ONFH) and their clinical and genetic risk factors. Methods:The present prospective cohort study enrolled patients who received their first GC therapy between July 2015 and January 2018 at Zhongshan Hospital. All patients did not receive any GC treatment before enrollment. Further, they planned to start GC treatment with the dose (equivalent prednisone) of ≥30 mg/d, lasted ≥3 weeks, or pulse dose ≥200 mg/d, lasted ≥3 d. Blood samples were collected before GC treatment to evaluate bone metabolism and its released factors. Hip MRI was performed at the 1st, 3rd, 6th, 12th and 24th month to diagnose GA-ONFH. All patients were followed-up for ≥2 years. The endpoint was regarded as diagnosis of GA-ONFH or completion of 2 years follow-up. Lasso regression was performed to determine which clinical features were associated with GA-ONFH. A nested case-control sub-cohort (A, n=12) was established prospectively based on the main cohort by 1∶1 matching. Whole exome sequencing was performed to screen differential and functional candidate single nucleotide polymorphisms and insertion-deletions (SNP/InDels). Another sub-cohort (B, n=50) was constructed retrospectively in patients with GA-ONFH and non-ONFH patients received standard high dose GC treatment for more than two years. The candidate SNP/InDels were verified by Sanger sequencing based on the patients from sub-cohort B. Results:A total of 96 patients were enrolled of which 88 of them (32 males and 56 females, mean age 42.30 years) completed follow-up. Eight cases (9.1%) were diagnosed with GA-ONFH. The median time from the start of GC therapy to the diagnosis of ONFH was 53.00(34.00,13.50) days. The baseline characteristics, such as age, sex and body mass index, indicated no significant difference between the ONFH group and the non-ONFH group. The cumulative GC dose of the ONFH patients in the first month was higher than that of non-ONFH [32.74(29.55, 47.05) mg/kg vs. 24.00(21.10, 29.45) mg/kg, Z=-2.410, P=0.016]. However, there was no significant difference of patients who underwent pulse therapy (37.5% vs. 10.0%, adjusted χ 2=2.829, P=0.093). The ratio of serum apolipoprotein B/apolipoprotein A1 (ApoB/ApoA1) in patients with ONFH was higher than that in non-ONFH group before GC use [0.95(0.80, 1.50) vs. 0.70(0.60, 0.80), Z=-2.875, P=0.000]. Due to the multicollinearity, Lasso regression model was performed to reduce overfitting. All variables were included in the model. The results suggested that higher ApoB/ApoA1 ratio, lower serum β-c-terminal telopeptide (β-CTX) and higher cumulative GC dose in the first month were the top three risk factors of GA-ONFH. This model had an accuracy of 0.982 in internal validation. Seven differential candidate SNP/InDels were found by whole exome sequencing of sub-cohort A. We further verified these SNP/InDels in sub-cohort B. The patients with COLEC12 mutation (rs2305027, G1816A) were at risk of GA-ONFH ( OR=6.00, 95% CI: 1.17, 30.73). Conclusion:Higher first-month GC dose, lower serum β-CTX level before treatment, higher ApoB/ApoA1 ratio and COLEC12 mutation (rs2305027, G1816A) could increase the risk of GA-ONFH.