Background Although flow diverter device(FDD)has brought revolutionized advances in endovascular treatment of intracranial aneurysms,it also presents considerable drawbacks as well,as the innovation for novel device h...Background Although flow diverter device(FDD)has brought revolutionized advances in endovascular treatment of intracranial aneurysms,it also presents considerable drawbacks as well,as the innovation for novel device has never stopped.This preclinical research aims to evaluate the safety and efficacy of a newly developed FDD,the EMBOPIPE,through in vivo and in vitro experiments.Methods Aneurysms were induced in 20 New Zealand white rabbits which were randomized to three follow-up groups according to the time elapsed after EMBOPIPE implantation(28,90,and 180 days).Additional EMBOPIPEs were implanted in the abdominal aorta to cover the renal artery in nine rabbits.Angiography was performed immediately after device placement in all groups.Aneurysm occlusion,patency of renal arteries,and pathological outcomes were assessed.For the in vitro experiments,we measured the thrombogenic potential of EMBOPIPEs(n=5)compared with bare stents(n=5)using the Chandler loop model.Evaluation indicators were the platelet counts,macroscopic observations and scanning electron microscopy.Results EMBOPIPEs were successfully deployed in 19 of 20 rabbit aneurysms(95.0%).The rates of complete or near-complete aneurysm occlusion were 73.3%,83.3%,and 100%in the 28-,90-,and 180-day groups,respectively.All renal arteries covered by EMBOPIPEs remained patent,and the mean difference in renal artery diameter before and after the device placement in the three groups was 0.07 mm,0.10 mm,and 0.10 mm,respectively(p=0.77).Renal pathology was normal in all cases.The pathological findings of the aneurysms were as follows:thickened and adequate neointimal coverage at the aneurysm neck,minimal inflammatory response,near-complete smooth muscle cell layer,and endothelialization along the device.In vitro experiments showed that the platelet counts were significantly higher in EMBOPIPE blood samples than in bare stent samples and that platelet adhesion to the device was lower in the EMBOPIPE stent struts compared with bare stent struts through macroscopic observations and scanning electron microscopy.Conclusions The EMBOPIPE can achieve high rates of aneurysm occlusion while maintaining excellent branch artery patency.It exhibited wonderful pathological results.This novel device with phosphorylcholine surface modification could reduce platelet thrombus attached to the stent struts.展开更多
Thrombosis is one of the main complications in patients implanted with ventricular assist device(VAD).The complicated structure and disturbed flow field within failure heart and blood pump play an important role in th...Thrombosis is one of the main complications in patients implanted with ventricular assist device(VAD).The complicated structure and disturbed flow field within failure heart and blood pump play an important role in thrombosis formation.In this study,the influence of Left ventricular(LV)volumes on flow field contributing to thrombosis formation within failure heart and VAD was investigated.Computational Fluid Dynamics(CFD)methods were employed to investigate the effect of different LV volumes on the thrombogenic potential of failure heart and VAD.Lagrangian methods were utilized to obtain information on platelet voyage trajectories.The concepts of mean and threshold of stress accumulation and residence time were introduced to accurately assess the likelihood of thrombus.Eulerian methods were used to identify thrombus-prone locations.CFD results showed that residence time(RT)was the main cause of thrombus formation in the failure heart,and the percentage of platelet trajectories above the RT threshold increased significantly with increasing LV volume.The RT in the left atrial appendage and LV increased significantly with LV volume increasing,which indicated that thrombus is prone to form there.Compared with the failure heart,non-physiological shear stress(NPSS)-caused platelet activation is the main reason for thrombus formation within VAD.The narrow zones(top clearance and secondary flow passage)within VAD have a high incidence of thrombus generation.In VAD patients,the LV volume has an important impact on thrombosis probability within failure heart,in which the larger size of the LV volume is,the higher risk of thrombosis will be.The size of LV volume has little effect on the thrombosis formation probability of VAD,where the NPSS plays the leading role in thrombosis formation.The finding of this study can be utilized to guild the clinical treatment and VAD structure optimization design for reducing the thrombosis risk.展开更多
基金supported by project funding:Peking Medical Research Institute No.2023-5
文摘Background Although flow diverter device(FDD)has brought revolutionized advances in endovascular treatment of intracranial aneurysms,it also presents considerable drawbacks as well,as the innovation for novel device has never stopped.This preclinical research aims to evaluate the safety and efficacy of a newly developed FDD,the EMBOPIPE,through in vivo and in vitro experiments.Methods Aneurysms were induced in 20 New Zealand white rabbits which were randomized to three follow-up groups according to the time elapsed after EMBOPIPE implantation(28,90,and 180 days).Additional EMBOPIPEs were implanted in the abdominal aorta to cover the renal artery in nine rabbits.Angiography was performed immediately after device placement in all groups.Aneurysm occlusion,patency of renal arteries,and pathological outcomes were assessed.For the in vitro experiments,we measured the thrombogenic potential of EMBOPIPEs(n=5)compared with bare stents(n=5)using the Chandler loop model.Evaluation indicators were the platelet counts,macroscopic observations and scanning electron microscopy.Results EMBOPIPEs were successfully deployed in 19 of 20 rabbit aneurysms(95.0%).The rates of complete or near-complete aneurysm occlusion were 73.3%,83.3%,and 100%in the 28-,90-,and 180-day groups,respectively.All renal arteries covered by EMBOPIPEs remained patent,and the mean difference in renal artery diameter before and after the device placement in the three groups was 0.07 mm,0.10 mm,and 0.10 mm,respectively(p=0.77).Renal pathology was normal in all cases.The pathological findings of the aneurysms were as follows:thickened and adequate neointimal coverage at the aneurysm neck,minimal inflammatory response,near-complete smooth muscle cell layer,and endothelialization along the device.In vitro experiments showed that the platelet counts were significantly higher in EMBOPIPE blood samples than in bare stent samples and that platelet adhesion to the device was lower in the EMBOPIPE stent struts compared with bare stent struts through macroscopic observations and scanning electron microscopy.Conclusions The EMBOPIPE can achieve high rates of aneurysm occlusion while maintaining excellent branch artery patency.It exhibited wonderful pathological results.This novel device with phosphorylcholine surface modification could reduce platelet thrombus attached to the stent struts.
基金the National Key R&D Program of China(Grant no.2020YFC0862900,2020YFC0862902,2020YFC0862904 and 2020YFC0122203)the Beijing Municipal Science and Technology Project(Grant no.Z201100007920003)+1 种基金the National Natural Science Foundation of China(Grant no.32071311)Key R&D project of Shanxi Province(Grant no.201903D321149).
文摘Thrombosis is one of the main complications in patients implanted with ventricular assist device(VAD).The complicated structure and disturbed flow field within failure heart and blood pump play an important role in thrombosis formation.In this study,the influence of Left ventricular(LV)volumes on flow field contributing to thrombosis formation within failure heart and VAD was investigated.Computational Fluid Dynamics(CFD)methods were employed to investigate the effect of different LV volumes on the thrombogenic potential of failure heart and VAD.Lagrangian methods were utilized to obtain information on platelet voyage trajectories.The concepts of mean and threshold of stress accumulation and residence time were introduced to accurately assess the likelihood of thrombus.Eulerian methods were used to identify thrombus-prone locations.CFD results showed that residence time(RT)was the main cause of thrombus formation in the failure heart,and the percentage of platelet trajectories above the RT threshold increased significantly with increasing LV volume.The RT in the left atrial appendage and LV increased significantly with LV volume increasing,which indicated that thrombus is prone to form there.Compared with the failure heart,non-physiological shear stress(NPSS)-caused platelet activation is the main reason for thrombus formation within VAD.The narrow zones(top clearance and secondary flow passage)within VAD have a high incidence of thrombus generation.In VAD patients,the LV volume has an important impact on thrombosis probability within failure heart,in which the larger size of the LV volume is,the higher risk of thrombosis will be.The size of LV volume has little effect on the thrombosis formation probability of VAD,where the NPSS plays the leading role in thrombosis formation.The finding of this study can be utilized to guild the clinical treatment and VAD structure optimization design for reducing the thrombosis risk.
