开胸经导管植入带瓣膜主动脉瓣支架置换犬主动脉瓣膜的短期疗效观察

目的:探讨开胸经导管植入带瓣膜支架置换主动脉瓣膜的可行性及术后短期疗效.方法:新鲜猪心包以0.6%戊二醛浸泡36 h后缝合在瓣膜环上,并将其固定在哑铃型镍钛记忆合金自膨胀支架上,制成带瓣膜主动脉瓣支架.选择健康杂种犬8只,通过开胸穿刺左心室心尖部,超声引导下将带瓣膜支架经导管植入至主动脉瓣处,置换犬自身主动脉瓣膜,术后定期行心电图、心脏彩超、CT及DSA造影检查,随访3个月,观察治疗效果.结果:成功制作带瓣膜主动脉瓣支架,经导管植入置换主动脉瓣膜后5只犬成活;心脏彩超及DSA造影检查证实术后支架位置及瓣膜功能良好,冠脉血流未受影响,术后3个月CT检查未发现支架移位,无明显并发症发生.结论:开胸经导管途径植入自制带瓣膜主动脉瓣支架可有效置换犬主动脉瓣膜,短期随访疗效理想.     

经导管人工生物主动脉瓣膜置换动物实验

目的:探索经导管人工生物主动脉瓣膜置换动物实验的可行性和安全性。方法:将自膨胀镍钛支架三叶式猪心包瓣膜装配入18F导管输送系统,在X线和超声引导下,经颈总动脉逆行性放置到8只健康的实验用绵羊主动脉瓣膜位置。植入前、后即刻进行主动脉根部及左心室造影、超声心动图检查评估植入支架瓣膜的功能及对冠脉血流灌注及二尖瓣功能等的影响。结果:6只实验动物植入支架瓣膜成形良好,无移位,冠脉血流未受影响,可见微量瓣周漏。因瓣膜位置放置不良导致2只实验动物术中死亡,其中1例因为瓣膜植入位置过深,影响到二尖瓣开放与闭合,引起急性心功能不全;另1例因为瓣膜植入位置偏高,影响到冠状动脉血流,导致急性心肌梗死和恶性心律失常。结论:经颈总动脉逆行性植入支架式主动脉生物瓣膜动物实验取得初步成功,即刻效果满意。     

新型带瓣膜主动脉瓣球囊扩张支架的研制及测试

目的通过体外测试评价新型带瓣膜主动脉瓣球囊扩张支架及输送装置的各项性能,为下一步动物体内实验提供依据。方法支架材料采用钴基合金,设计成圆柱形网状结构。人工瓣膜取材于经处理的新鲜牛心包,将人工瓣膜缝合在支架上制成带瓣膜主动脉支架。使用人工心脏瓣膜脉动流测试仪和人工心脏瓣膜加速疲劳测试仪,分别对带瓣膜支架瓣叶材料脉动流和人工瓣膜耐疲劳情况进行测试。将带瓣膜支架压缩至自行研制的输送装置的球囊上,取离体羊心脏标本,经升主动脉将支架直视下置入羊主动脉瓣位置,扩张球囊释放支架,注水观察瓣膜功能。结果人工瓣膜瓣叶脉动流测试结果表明人工瓣膜启闭良好,无明显反流,符合生理需求。人工瓣膜耐疲劳测试结果表明瓣膜耐疲劳性能良好。带瓣膜支架经压缩后可通过输送鞘管送入离体羊主动脉瓣,支架释放后可牢固地置于羊主动脉瓣位置,人工瓣膜启闭功能良好。结论带瓣膜支架设计合理,性能良好,可用于动物经导管主动脉瓣置入实验。     

带瓣膜二尖瓣支架的研制及体外经导管植入实验

目的:研制可经导管植入的带瓣膜二尖瓣支架,并探索二尖瓣支架植入方法的可行性.方法:用超弹性镍钛记忆合金丝编织双盘状网状支架,中间有腰部连接,内置瓣膜环.将新鲜的羊心包给予0.6%戊二醛浸泡36 h后缝合在瓣膜环上,制成带瓣膜二尖瓣支架.取离体的山羊心脏及大血管标本,直视下穿刺房闻隔,将输送鞘管从下腔静脉送到左心室,沿鞘管将带瓣膜二尖瓣支架送入左心室,打开左室面,回拉鞘管,确认左室面卡住瓣环口后,释放左房面,完成体外经导管植入实验.注水实验观察瓣膜启闭功能.结果:制备的带瓣膜二尖瓣支架可牢固地置于自体二尖瓣环位置,反复牵拉后未见支架脱入心腔,同时观察到原有二尖瓣瓣叶、腱索等均被夹在双盘状支架之间,瓣下结构无破坏.瓣膜启闭功能良好.结论:人工带瓣膜二尖瓣支架设计合理,可经导管安全释放,瓣膜功能良好.     

带瓣膜主动脉瓣支架的研制及体外经导管植入实验

目的:评价一种新的带瓣膜主动脉瓣支架经导管植入的可行性及其对冠脉血流的影响。方法:用超弹性镍钛记忆合金丝编织成圆柱状网状支架,腰部凹陷,并将网孔扩大,下段内置瓣膜环,将新鲜的猪心包经脱细胞处理后给予0.6%戊二醛浸泡36 h,缝合在瓣膜环上,制成带瓣膜主动脉瓣支架。支架近端连接丝线,收入鞘管,取离体猪心脏标本,经升主动脉将带瓣膜支架送至左室,直视下送至主动脉瓣位置,释放支架,注水观察瓣膜功能及冠脉水流量。结果:制备的带瓣膜主动脉瓣支架可牢固地置于原主动脉瓣位置,释放后可回收,人工瓣膜启闭功能好,冠脉流量及二尖瓣前叶活动未受影响。结论:带瓣膜主动脉瓣支架设计合理,可经导管释放并回收,瓣膜功能良好,不影响冠脉开口,可用于动物体内植入实验研究。     

带瓣膜主动脉瓣支架的研制及经导管植入动物实验

目的:研制可经导管植入的带瓣膜主动脉瓣支架,探索经导管植入该瓣膜支架的可行性。方法:采用0.2 mm镍钛记忆合金丝编织内径为15~19 mm的网状支架。取牛心包,经固定处理后,按仿形类比设计的方法修剪成瓣叶,并缝合在支架的远端,制成带瓣膜主动脉瓣支架。所有瓣膜支架行体外冲水实验、释放实验、体外管道内释放及静态实验。小香猪7只,采用经导管逆行的方法行升主动脉内置入瓣膜支架的动物实验。结果:研制的带瓣膜主动脉瓣支架,经体外试验证明瓣膜关闭良好,反向均为中心水流,并明确该瓣膜支架能经导管顺利释放,释放后能迅速完全扩张,在管道内固定牢靠。采用12F~16F的输送导管,6只实验动物经髂总动脉植入,所有瓣膜支架均能顺利跨过主动脉弓达升主动脉,并顺利释放,除1例瓣膜支架释放后未完全扩张、移位外,其余均迅速完全扩张、固定良好。24 h后处死动物解剖,见支架固定,支架内未见血栓。结论:该带瓣膜主动脉瓣支架启闭功能、自膨功能良好,压缩后的体积符合经导管植入的要求,可采用逆行的方法经髂总动脉植入于升主动脉内,释放后能迅速扩张,固定牢靠。     

带瓣膜三尖瓣支架的研制及体外经导管植入实验

目的:研制可经导管植入的带瓣膜三尖瓣支架,探索置换三尖瓣的技术.方法:用超弹性镍钛记忆合金丝编织双盘状网状支架,两盘中间有腰部连接,内置瓣膜环.将新鲜的羊心包脱细胞处理后给予0.6%戊二醛浸泡48 h后缝合在瓣膜环上,制成带瓣膜三尖瓣支架.取离体的山羊心脏标本,用输送鞘管经下腔静脉穿过三尖瓣口,打开右室面,回拉鞘管,确认右室面卡住瓣环口后,释放右房面,完成体外经导管植入实验.注水实验观察瓣膜启闭功能.结果:制备的带瓣膜三尖瓣支架可牢固地置于自体瓣环位置,反复牵拉后未见支架脱入心腔,同时观察到原有三尖瓣瓣叶、腱索等均被夹在双盘状支架之间,瓣下结构无破坏.瓣膜启闭功能良好.结论:人工带瓣膜三尖瓣支架设计合理,可经导管安全释放,瓣膜功能良好.     

一种新型的对冠脉无影响的主动脉瓣膜支架

目的 通过体外测试和动物实验,采用经导管逆行主动脉瓣植入的方法,评价一种新型主动脉瓣膜支架的可行性和安全性.方法 采用猪的心包制作一种新型主动脉瓣膜支架.所有支架在体外均进行流体力学、扩张和释放实验.将这些支架采用逆行经导管的方法植入6头猪体内.这些猪在植入12 h后进行分析.结果 离体实验显示这种新型主动脉瓣膜支架的瓣叶的闭合是有效的,支架可以通过导管释放,然后完全开展并迅速固定.左右冠状动脉血流量在瓣膜支架植入后没有显著的变化.在体内试验中,逆行经导管植入主动脉瓣膜支架于6头猪体内.然后,有一头猪在植入10 h候因为支架没有完全打开导致死亡.在其余5头猪中,瓣膜支架打开良好,无主动脉瓣逆流,也没有血栓形成.结论 该新型主动脉瓣膜支架稳定性好,可以避免瓣叶对冠状动脉的影响.     

经皮经股动脉逆行主动脉瓣植入术

背景:经皮经静脉顺行途径主动脉瓣植入术已有报道,但受到置疑。经股动脉逆行主动脉瓣植入有着潜在的优势。本文中描述经股动脉逆行人工主动脉瓣植入术,并报道初期经验。方法和结果:人工瓣膜由覆有三叶马心包瓣膜及纤维套囊的不锈钢支架构成。常规主动脉球囊瓣膜成形术后,从股动脉至主动脉穿入一个22F或24F鞘管。采用可控、可弯曲导管便于操纵人工瓣膜绕过主动脉弓并通过狭窄的自身瓣膜。在瓣环内球囊扩张展开人工瓣膜时,采用快速心室起搏以减少心输出量。18例因存在并发症而被认为外科手术高危的患者(年龄81±6岁)尝试了行经皮主动脉人工瓣…     

超微孔膨体聚四氟乙烯（ePTFE）自膨式介入肺动脉瓣膜动物实验研究

目的 评价自主研制的超微孔膨体聚四氟乙烯（expanded polytetrafluoroethylene,ePTFE）自膨式介入肺动脉瓣膜动物体内原位置换后的早期实验效果。方法 选用厚度0.1 mm经磷酰胆碱表面接枝的超微孔ePTFE材料制作成三叶自膨式介入心脏瓣膜。雄性绵羊7只,体质量（27.2±1.2）kg,全麻右侧开胸,右室近心尖处缝荷包,将人工瓣膜经导管从右室心尖送入肺动脉瓣行原位置换。术后即时通过心血管造影、右心导管检查,术后4周通过经胸心脏超声、右心导管检查对介入瓣膜功能进行早期评价。结果 7只羊手术均获得成功,术后即时心血管造影提示人工瓣膜位置满意,开闭良好。1只羊因肺部感染合并感染性心内膜炎于术后16 d死亡,其余6只羊随访4周状况良好。术后4周经胸心脏超声提示人工瓣膜工作正常,无明显血栓或赘生物,4只羊无明显反流,2只羊微量反流。右心导管检查提示术后即时人工瓣膜峰值跨瓣压差为（6.0±2.2）mmHg （1 mmHg=0.133 kPa）,术后4周为（9.5±2.7）mmHg,且术后4周与术前[（3.5±1.0）mmHg]相比差异有统计学意义（P<0.05）。结论 超微孔ePTFE自膨式介入肺动脉瓣经右室心尖入路置入成功率高,人工瓣膜早期功能良好。     

Transcatheter Aortic Valve Implantation Assisted with Microcatheter: A New Method to Avoid Coronary Artery Obstruction

Background:

Lack of fluoroscopic landmarks can make valve deployment more difficult in patients with absent aortic valve (AV) calcification. The goal of this article was to evaluate the feasibility and effectiveness of transcatheter implantation of a valved stent into the AV position of a goat, assisted with a microcatheter which provides accurate positioning of coronary artery ostia to help valved stent deployment.

Methods:

The subjects were 10 healthy goats in this study. A microcatheter was introduced into the distal site of right coronary artery (RCA) through femoral artery sheath. A minimal thoracic surgery approach was used to access the apex of the heart. The apex of the left ventricle was punctured; a delivery catheter equipped with the valved stent was introduced over a stiff guidewire into the aorta arch. We could accurately locate the RCA ostia through the microcatheter placed in the RCA under fluoroscopy. After correct valve position was confirmed, the valved stent was implanted after rapid inflation of the balloon. The immediate outcome of the function of the valved stents was evaluated after implantation.

Results:

All ten devices were successfully implanted into the AV position of the goats. Immediate observation after the procedure showed that the valved stents were in the desired position after implantation by angiography, echocardiogram. No obstruction of coronary artery ostia occurred, and no moderate to severe aortic regurgitation was observed.

Conclusions:

When the procedure of transcatheter implantation of a balloon-expandable valved stent into the AV position of goats is assisted with microcatheter positioning coronary artery ostia, the success rate of operation can be increased in those with noncalcified AV.     

Percutaneous aortic valve replacement using a W-model valved stent: a preliminary feasibility study in sheep

Background Percutaneous aortic valve replacement is a promising strategy in the treatment of patients with aortic valve stenosis. And many kinds of valved stents have been implanted in selected patients worldwide. However, the clinical experience is still limited. We developed a W-model valved stent and evaluated the feasibility and safety of percutaneous implantation of the device in the native aortic valve position.
Methods A self expanding nitinol stent with W-model, containing porcine pericardium valves in its proximal part, was implanted in six sheep by means of a 14 French catheter through the right common iliac artery under guidance of fluoroscopy. During stent deployment the original aortic valve was pushed against the aortic wall by the self expanding force of the stent while the new valve was expanded. These sheep were followed up shortly after procedure with supra-aortic angiogram and left ventriculography. Additionally, one sheep was sacrificed after the procedure for anatomic evaluation.
Results It was possible to replace the aortic valve in the beating heart in four sheep. The procedure failed in two sheep due to coronary orifice occlusion in one case and severe aortic valve regurgitation in the other case. One sheep was killed one hour after percutaneous aortic valve replacement for anatomic evaluation. There were no signs of damage of the aortic JntJma, or of obstruction of the coronary orifice,
Conclusions Percutaneous aortic valve replacement with a W-model valved stent in the beating heart is possible. Further studies are mandatory to assess safety and efficacy of this kind of valved stent in larger sample size and by longer follow-up period.     

自膨式带瓣膜主动脉瓣支架对冠脉影响的体外研究

目的 探讨自膨式带瓣膜主动脉瓣支架(瓣膜支架)行体外原位主动脉瓣置换后对冠状动脉的影响.方法 采用12只离体小香猪的升主动脉,经冠脉流量测试系统测得基础的左右冠脉流量(基础流量)、瓣膜支架植入后的冠脉流量(保留瓣膜组)及去除正常瓣膜后再次植入支架的左右冠脉流量(去除瓣膜组),并结合内窥镜检查及解剖观察支架及冠脉开口的情况.结果 保留瓣膜组左冠流量较基础流量明显较少(29.46%, P<0.05),右冠流量虽有所减少,但差异无统计学意义(P>0.05).去除瓣膜组左右冠脉流量较基础流量有所减少(左冠6.82%,右冠5.37%),但差异均无统计学意义(P>0.05),左冠流量较保留瓣膜时明显改善(32.09%,P<0.05).解剖发现左冠开口相对较低.内窥镜检查发现,在保留瓣膜组正常主动脉瓣瓣叶被支架压向侧壁,造成左冠开口完全阻塞3只,部分阻塞4只,右冠开口部分阻塞3只.两组中共见5只瓣膜支架的瓣脚影响冠脉开口,使其部分阻塞,其中左冠4只,右冠1只.结论 该自膨式瓣膜支架行原位主动脉瓣植入后,被压向侧壁的瓣叶易使左冠开口阻塞.同时瓣膜支架的瓣脚有时也会部分影响冠脉流量.     

Percutaneous valve stent insertion to correct the pulmonary regurgitation: an animal feasibility study

Background Pulmonary regurgitation leads to progressive right ventricular dysfunction, susceptibility to arrhythmias,and sudden cardiac death. Percutaneous valve replacement has been developed in recent years, providing patients with an alternative option. Percutaneous pulmonary valve replacement has been recently introduced into clinical practice. The goal of this study was to evaluate the feasibility of percutaneous valve stent insertion to correct the pulmonary regurgitation in sheep using a cup-shaped valve stent.Methods Pulmonary regurgitation was created by percutaneous cylindrical stent insertion in native pulmonary annulus of 8 sheep. One month after the initial procedure, the sheep with previous cylindrical stent implanted underwent the same implantation procedure of pulmonary valve stent. The valve stent consisted of a cup-shaped stent and pericardial valves.Hemodynamic assessments of the bioprosthetic pulmonary valve were obtained by echocardiography at immediately post-implant and at 2 months follow up.Results Successful transcatheter cylindrical stent insertion was performed in 7 sheep but failed in 1 sheep because the cylindrical stent was released to right ventricle outflow tract. After one month the 7 sheep with pulmonary regurgitation underwent valve stent implantation successfully. Echocardiography confirmed the stents were in desired position during the follow-up. No evidence of pulmonary valve insufficiency occurred in any animals. Echocardiography showed all heart function markers were normal.Conclusions Percutaneous cylindrical stent insertion to induce significant pulmonary regurgitation in sheep was feasible, simple and reproducible. Percutaneous pulmonary valve stent implantation can reduce pulmonary regurgitation in a sheep model. Further development of animal model and clinical trials are warranted.