Background Tetralogy of Fallot(TOF)is the most common cyanotic heart defect,accounting for 10%of all congenital defects.Pulmonary valve stenosis(PVS)is one common right ventricular outflow tract obstruction problem in...Background Tetralogy of Fallot(TOF)is the most common cyanotic heart defect,accounting for 10%of all congenital defects.Pulmonary valve stenosis(PVS)is one common right ventricular outflow tract obstruction problem in patients with TOF.Congenital bicuspid pulmonary valve(BPV)is a condition of valvular stenosis,which morphologic feature is the presence of only two pulmonary leaflets instead of the normal tri-leaflet.Congenitally BPV are uncommon and the occurrence is often associated with TOF.Methods The three-dimensional geometric reconstruction of pulmonary root(PR)were based on well-accepted mathematical analytic models with physiological parameters obtained from a typical sample of the pulmonary root used in clinical surgery.The PR geometry included valvular leaflets,sinuses,interleaflet triangles and annulus.The dynamic computational models of normal PR with tri-leaflet and PR with BPV in patients with TOF were developed to investigate the effect of geometric structure of BPV on valve stress and strain distributions and the geometric orifice area.Mechanical properties of pulmonary valve leaflet were obtained from biaxial testing of human pulmonary valve left leaflet,and characterized by an anisotropic Mooney-Rivlin model.The complete cardiac cycle was simulated to observe valve leaflet dynamic stress and strain behaviors.Results Our results indicated that stress/strain distribution patterns of normal tri-leaflet pulmonary valve(TPV)and the BPV were different on valve leaflets when the valve was fully open,but they were similar when valves were completely closed.When the valve was fully open,the BPV maximum stress value on the leaflets was 218.1 kPa,which was 128.0%higher than of the normal TPV value(95.6 kPa),and BPV maximum strain value on the leaflets was 70.7%higher than of the normal TPV.The location of the maximum stress from TPV and BPV were also different,which were found at the bottom of the valve near the leaflet attachment for TPV and the vicinity of cusp of the fusion of two leaflets for BPV,respectively.During the valve was fully open,the stress distribution in the interleaflet triangles region of the PR was more asymmetric in the BPV model compared with that in the normal TPV model,and the largest change on the PR with the geometrical variations in the two models was 39.6%in maximum stress.This stress asymmetry indicates that BPV may be one of the causes of post-stenotic pulmonary artery dilatation and aneurysm in patients with TOF.The cusp of the BPV model showed significant eccentricity during peak systolic period,and its geometric orifice area value in the completely opened position of valve was reduced 57.5%from that of the normal TPV model.Conclusions Our initial results demonstrated that valve geometrical variations with BPV may be a potential risk factor linked to occurrence of PVS in patients with TOF.Computational models could be used as an effective tool to identifying possible linkage between pulmonary valve malformation disease development and biomechanical factors,better design of artificial valves and new surgical procedures without testing those on patients.Large-scale clinical studies are needed to validate these preliminary findings.展开更多
目的:探讨二叶式主动脉瓣狭窄患者主动脉根部形态学特点对经导管主动脉瓣置换术(TAVR)疗效的影响。方法:回顾性选取2014年1月至2016年12月在阜外医院、四川大学华西医院及浙江大学附属第二医院行TAVR的二叶式主动脉瓣狭窄患者49例。分...目的:探讨二叶式主动脉瓣狭窄患者主动脉根部形态学特点对经导管主动脉瓣置换术(TAVR)疗效的影响。方法:回顾性选取2014年1月至2016年12月在阜外医院、四川大学华西医院及浙江大学附属第二医院行TAVR的二叶式主动脉瓣狭窄患者49例。分析患者主动脉根部形态学特点、手术有效性及安全性,并进行随访。结果:二叶式主动脉瓣无嵴与带嵴类型占比相当(55.1%vs 44.9%),瓣叶钙化程度重[钙化体积HU850=(604.1±318.7) mm^3],平均瓣环周长大于平均瓣环上水平周长[(78.8±7.4) mm vs (67.1±6.7) mm,P<0.001],平均左心室流出道(LVOT)周长大于平均瓣环周长[(81.6±10.5) mm vs (78.8±7.4) mm,P=0.003]。置入瓣中瓣患者12例(24.5%),瓣膜置入过深患者14例(34.1%)。置入瓣中瓣患者比无瓣中瓣患者瓣环平均内经[(26.8±2.4) mm vs(23.9±2.0) mm,P<0.001]、周长[(85.7±7.0) mm vs (76.6±6.1) mm,P<0.001]及LVOT平均内径[(28.4±2.7) mm vs (24.3±3.1) mm,P<0.001]、周长[(91.3±9.1) mm vs (78.4±8.9) mm,P<0.001]更大,LVOT周长/瓣环上水平周长比值虽差异无统计学意义[(125.5±12.3)%vs (119.4±15.7)%,P=0.067],但趋近阈值。瓣膜置入过深患者比无置入过深患者LVOT周长/瓣环周长比值更大[(108.0±7.4)%vs (101.2±6.7)%,P=0.005]。结论:二叶式主动脉瓣患者的瓣环和LVOT平均内径及LVOT周长/瓣环周长比值对于TAVR中瓣中瓣的置入及瓣膜置入深度具有一定影响。展开更多
基金supported in part by National Sciences Foundation of China grants ( 11672001, 81571691 and 81771844)
文摘Background Tetralogy of Fallot(TOF)is the most common cyanotic heart defect,accounting for 10%of all congenital defects.Pulmonary valve stenosis(PVS)is one common right ventricular outflow tract obstruction problem in patients with TOF.Congenital bicuspid pulmonary valve(BPV)is a condition of valvular stenosis,which morphologic feature is the presence of only two pulmonary leaflets instead of the normal tri-leaflet.Congenitally BPV are uncommon and the occurrence is often associated with TOF.Methods The three-dimensional geometric reconstruction of pulmonary root(PR)were based on well-accepted mathematical analytic models with physiological parameters obtained from a typical sample of the pulmonary root used in clinical surgery.The PR geometry included valvular leaflets,sinuses,interleaflet triangles and annulus.The dynamic computational models of normal PR with tri-leaflet and PR with BPV in patients with TOF were developed to investigate the effect of geometric structure of BPV on valve stress and strain distributions and the geometric orifice area.Mechanical properties of pulmonary valve leaflet were obtained from biaxial testing of human pulmonary valve left leaflet,and characterized by an anisotropic Mooney-Rivlin model.The complete cardiac cycle was simulated to observe valve leaflet dynamic stress and strain behaviors.Results Our results indicated that stress/strain distribution patterns of normal tri-leaflet pulmonary valve(TPV)and the BPV were different on valve leaflets when the valve was fully open,but they were similar when valves were completely closed.When the valve was fully open,the BPV maximum stress value on the leaflets was 218.1 kPa,which was 128.0%higher than of the normal TPV value(95.6 kPa),and BPV maximum strain value on the leaflets was 70.7%higher than of the normal TPV.The location of the maximum stress from TPV and BPV were also different,which were found at the bottom of the valve near the leaflet attachment for TPV and the vicinity of cusp of the fusion of two leaflets for BPV,respectively.During the valve was fully open,the stress distribution in the interleaflet triangles region of the PR was more asymmetric in the BPV model compared with that in the normal TPV model,and the largest change on the PR with the geometrical variations in the two models was 39.6%in maximum stress.This stress asymmetry indicates that BPV may be one of the causes of post-stenotic pulmonary artery dilatation and aneurysm in patients with TOF.The cusp of the BPV model showed significant eccentricity during peak systolic period,and its geometric orifice area value in the completely opened position of valve was reduced 57.5%from that of the normal TPV model.Conclusions Our initial results demonstrated that valve geometrical variations with BPV may be a potential risk factor linked to occurrence of PVS in patients with TOF.Computational models could be used as an effective tool to identifying possible linkage between pulmonary valve malformation disease development and biomechanical factors,better design of artificial valves and new surgical procedures without testing those on patients.Large-scale clinical studies are needed to validate these preliminary findings.
文摘目的:探讨二叶式主动脉瓣狭窄患者主动脉根部形态学特点对经导管主动脉瓣置换术(TAVR)疗效的影响。方法:回顾性选取2014年1月至2016年12月在阜外医院、四川大学华西医院及浙江大学附属第二医院行TAVR的二叶式主动脉瓣狭窄患者49例。分析患者主动脉根部形态学特点、手术有效性及安全性,并进行随访。结果:二叶式主动脉瓣无嵴与带嵴类型占比相当(55.1%vs 44.9%),瓣叶钙化程度重[钙化体积HU850=(604.1±318.7) mm^3],平均瓣环周长大于平均瓣环上水平周长[(78.8±7.4) mm vs (67.1±6.7) mm,P<0.001],平均左心室流出道(LVOT)周长大于平均瓣环周长[(81.6±10.5) mm vs (78.8±7.4) mm,P=0.003]。置入瓣中瓣患者12例(24.5%),瓣膜置入过深患者14例(34.1%)。置入瓣中瓣患者比无瓣中瓣患者瓣环平均内经[(26.8±2.4) mm vs(23.9±2.0) mm,P<0.001]、周长[(85.7±7.0) mm vs (76.6±6.1) mm,P<0.001]及LVOT平均内径[(28.4±2.7) mm vs (24.3±3.1) mm,P<0.001]、周长[(91.3±9.1) mm vs (78.4±8.9) mm,P<0.001]更大,LVOT周长/瓣环上水平周长比值虽差异无统计学意义[(125.5±12.3)%vs (119.4±15.7)%,P=0.067],但趋近阈值。瓣膜置入过深患者比无置入过深患者LVOT周长/瓣环周长比值更大[(108.0±7.4)%vs (101.2±6.7)%,P=0.005]。结论:二叶式主动脉瓣患者的瓣环和LVOT平均内径及LVOT周长/瓣环周长比值对于TAVR中瓣中瓣的置入及瓣膜置入深度具有一定影响。
