光氧化处理牛颈静脉带瓣管道重建肺动脉与右心室连接

目的观察光氧化处理的牛颈静脉带瓣管道用于重建右心室—肺动脉连接后,在体内循环系统中与血流接触条件下的抗钙化性能及其血流动力学性能。方法以经光氧化反应处理的牛颈静脉带瓣管道为研究对象,以单纯戊二醛交联固定的牛颈静脉带瓣管道作为对照,建立犬重建右心室—肺动脉连接的动物模型;实验动物饲养观察10个月后,通过超声心动图和心导管检查等方法评价两种不同方法固定处理的牛颈静脉带瓣管道重建犬右心室—肺动脉连接后的血流动力学性能,并了解牛颈静脉管道内的瓣膜在犬的右心系统内的功能。屠宰实验动物后取出标本,通过原子吸收光谱法测定组织钙含量,von Kossa钙盐染色观察组织钙化情况。结果心脏超声显示两组管道均通畅,瓣叶活动良好。光氧化处理组结扎肺动脉前、后直接测压及术后9~10个月通过心导管测压,所测得的跨瓣压差维持在较低水平,跨瓣压差无明显升高;戊二醛组结扎肺动脉前、后及术后9~10个月测得的跨瓣压差与光氧化组相似。光氧化组管道血管壁钙含量为7.60±8.02 mg/g,戊二醛组管道血管壁钙含量为22.05±10.78 mg/g,两组有显著性差异(P<0.05);光氧化组和戊二醛组管道瓣膜钙含量分别为0.74±0.23 mg/g和0.88±0.69 mg/g,两组相比无统计学差异(P>0.05)。结论光氧化反应处理固定的牛颈静脉带瓣管道可用于重建右心室—肺动脉连接,血流动力性能良好,与自体肺动脉相当,远期血流动力学性能尚待进一步观察研究。光氧化反应处理固定的牛颈静脉带瓣管道在狗的动物模型中,抗钙化性能优于戊二醛固定的牛颈静脉管道。     

新型无支架生物瓣带瓣管道用于右室流出道重建

目的:验证新型无支架生物瓣带瓣管道应用于右室流出道重建术中的有效性和安全性。方法:2007年11月～2008年5月,全组7例复杂先天性心脏病患者使用了新型无支架牛心包带瓣管道重建右室流出道,其中Rastelli手术6例、Nikaidoh手术1例。通过术后不同时期超声检查结果,记录肺动脉压、血流速度、新建肺动脉瓣跨瓣压差及开口面积和返流情况,了解肺动脉管道直径、有无瘤样扩张以及远端吻合口压差等,对移植的无支架生物瓣带瓣管道的临床性能进行评价。结果:所有患者住院期间均无吻合口渗血、心内膜炎、血栓栓塞等带瓣管道相关并发症发生,恢复顺利,均治愈出院。术后1～4月和6月以上超声检查均提示移植的管道通畅,管壁无变薄、钙化,无瘤样扩张,无明显肺动脉瓣返流等。结论:新型无支架生物瓣带瓣管道具有管壁弹性好、易于缝合、术后排斥反应少等优点,且有良好抗返流作用,早期疗效满意。     

肺动脉带瓣支架植入术实验研究

目的把猪心包为瓣膜材料的带瓣肺动脉瓣膜支架植入动物体内，探讨该技术可行性。方法猪心包经过提取、打磨、浸泡等处理后，制作成三瓣叶形状，用聚丙烯线固定于自膨胀镍钛支架内。在0．6％戊二醛浸泡36h后保存于60％的乙醇中。打开胸腔及心包，暴露心脏，穿刺右心室前壁，在超声监测下．成功对7头羊和1头猪植入肺动脉带瓣支架。结果全部植入支架的动物未出现并发症。术前及术后即刻、24h、1个月和2个月行心脏超声，术后第2和第3个月行造影检查，支架内瓣膜开放良好，无反流。带瓣支架置人前后右心室压力、肺动脉压力，未出现明显的血流动力学变化，1例羊术后2个月于肺动脉到右心室连续拉管测得12mmHg（1mmHg=0．133kPa）压差，该例肺动脉带瓣支架植入位置偏低，处于右心室流出道位置，其他植入位置正常。术后第2个月行大体及光镜观察发现固有瓣膜因被支架压靠在肺动脉壁内而被废用，支架的另一端处于右心室流出道，支架内瓣膜未见钙化灶，周围组织无炎症反应，少量上皮组织爬行，肺、肝、脾、肾等重要器官均无血栓现象。电镜观察示周围组织细胞形态结构正常．支架内瓣膜纤维组织形态结构正常。结论以猪心包为瓣膜材料的带瓣肺动脉支架在动物体内应用安全有效。     

在肾动脉下方的腹主动脉上犬同种带瓣主、肺动脉移植模型

目的：建立在肾动脉下方的腹主动脉上犬同种带瓣主、肺动脉移植实验模型，以研究其移植后免疫学、组织活性和超微结构改变以及宿主细胞替换供体组织过程。方法：将犬分为４组，采用犬同种带瓣主、肺动脉沿血流方向移植于异性受体犬肾动脉下方的腹主动脉上的方法。结果：全组２８例均存活，满足实验设计要求。结论：本实验模型具有手术操作容易、成功率高、术后并发症少、费用低廉等优点     

非缝合式无支架异种主动脉生物瓣膜的研制

目的: 研制新型非缝合式无支架异种主动脉生物瓣膜,在体外对其功能进行初步研究。方法: 将猪主动脉瓣缝合到NiTi形状记忆合金支架上,在离体猪心脏内置入新型瓣膜,肉眼及彩超下观测瓣膜闭合、冠状动脉血流及瓣周漏情况。通过TH-1200型人工心脏瓣膜脉动流测试系统测定25#非缝合式无支架异种主动脉生物瓣膜平均跨瓣压差、返流百分比、瓣膜开口面积。结果: 新型瓣膜能较简单的植入离体猪心脏内。且不同压力（80～250mmHg）下,瓣膜闭合良好,无明显瓣周漏,冠状动脉血流良好;心脏彩超检测瓣周结构与主动脉壁之间可见无回声间隙,无明显的瓣周漏。体外脉动实验提示新型瓣膜与机械瓣膜相比跨瓣压差小,返流少,开口面积大。结论: 该型瓣膜制备相对简单,具有血流动力学良好,跨瓣压小,无需抗凝等优点,可简化手术操作,降低手术难度。     

经皮“瓣上瓣”支架植入对急性主动脉瓣反流动物短期预后的影响

目的:探讨经皮冠状动脉开口上方植入带瓣膜支架,这种"瓣上瓣"技术对急性主动脉瓣反流动物短期预后的影响。方法:选择体重为(18.7±4.1)kg的健康犬10只,建立急性主动脉瓣反流模型。模型建立成功后饲养1周,心脏超声评价心功能和瓣膜功能,同时将带瓣膜支架经导管植入至冠脉开口的上方,随访6个月,观察实验效果。结果:10只犬中有8只成功建立急性主动脉瓣反流模型,1周后成功将带瓣膜支架植入到冠状动脉开口上方,术后6个月随访发现,瓣膜支架的位置和功能良好,心脏功能明显改善,主动脉瓣膜反流明显减轻。结论:经皮"瓣上瓣"支架植入可以明显改善急性主动脉瓣反流动物的短期预后,该技术可以作为一种急救措施用于临床。     

蛋白多糖在脱细胞猪肺动脉带瓣管道中抗钙化的作用

目的:证实去除细胞外基质蛋白多糖对提高脱细胞猪肺动脉带瓣管道抗钙化性能的作用,为研制组织工程化肺动脉带瓣管道做准备。方法:实验分为3组,即A组:为新鲜猪肺动脉带瓣管道组织,B组:用胰蛋白酶+Triton X-100处理的脱细胞猪肺动脉带瓣管道组织和C组:在B组处理的基础上再经透明质酸酶消化,去除细胞外蛋白多糖基质成分的猪肺动脉带瓣管道组织,每组4份(n=4)。方法:实验室:将3组样本分别进行HE染色后,用光镜和扫描电镜观察肺动脉管壁及瓣膜组织的变化。采用盐酸胍抽提结合阿利新蓝染色法测定蛋白多糖的含量。同时将3组样本包埋于大鼠皮下,于6周后取出标本进行Van Kosaa银染色法(钙盐染色)和原子吸收分光光度计法分别定性、定量分析组织的钙化程度。结果:光镜和电镜检查结果显示,猪肺动脉管壁和瓣膜组织的细胞可以较完整的去除,纤维网架结构可以完整保持。蛋白多糖含量的测定显示,与A、B组相比,C组细胞外基质蛋白多糖的含量显著下降(P<0.05)。大鼠皮下包埋实验显示,与A、B两组相比,C组的钙化反应更少,管壁组织钙的含量显著下降(P<0.05)。结论:采用胰蛋白酶+Triton X-100脱细胞方法可以达到去除细胞的目的。通过大鼠皮下包埋实验证明,采用透明质酸酶消化减少细胞外基质蛋白多糖的含量可以进一步减少脱细胞组织的钙化反应,为组织工程肺动脉带瓣管道的构建提供较为理想的脱细胞基质材料。     

去细胞组织工程猪肺动脉带瓣管道的生物相容性研究

目的:探讨去细胞组织工程猪肺动脉带瓣管道的生物相容性。方法:①新鲜猪肺动脉带瓣管道组织3份,A组为对照组,B、C组采用胰蛋白酶+Triton X-100对新鲜猪肺动脉带瓣管道进行去细胞处理,C组在去细胞处理后行明胶嵌合再处理;②对3组瓣膜及管壁组织行大鼠皮下包埋实验,8周后观察材料的组织相容性和生长情况;③通过动态凝血试验、溶血试验、血小板粘附性能试验分析3种组织材料的血液相容性。结果:与A组相比,B组及C组的炎性细胞浸润显著减少,C组仅有轻微组织反应;B、C组材料组织相容性好,并于8周后有纤维细胞长入。相对A组及B组,C组的瓣膜及管壁组织具有更低的凝血率,OD-凝血时间曲线下降更缓慢且吸光度高,同时血小板粘附更少且没有明显变形和伪足。结论:这种去细胞组织工程猪肺动脉带瓣管道不仅具有极低的免疫原性,而且具有一定的生长潜能、良好的组织相容性及血液相容性,有可能成为一种新的、理想的组织工程肺动脉带瓣管道支架材料。     

小左心室和大左心室患者进行相同机械二尖瓣置换术后围手术期血流动力学研究

目的:探讨比较小左心室和大左心室患者进行大口径二尖瓣置换术的围手术期血流动力学变化。方法:进行单独二尖瓣置换术的患者按照左心室舒末径<40 mm、>40 mm而<60 mm和>60mm分为3组,均进行相同大小On-X二尖瓣置换。每组患者手术后均进行各瓣膜跨瓣压差、流速和肺动脉压的测定,最后用SPSS统计分析。结果:在进行同样大小二尖瓣置换后,3组心室大小不同的患者术后主动脉瓣流速、二尖瓣流速和肺动脉压力在各组间并没有统计学差异。结论:在注意心肌保护和围手术期处理的条件下,左心室舒张末径较小的患者和大左心室患者在接受较大口径机械二尖瓣置换时,围手术期血流动力学无明显差异。     

一种慢性主动脉瓣关闭不全动物模型建立的实验研究

目的:探讨通过介入方法破坏主动脉瓣膜,建立一种慢性主动脉瓣膜关闭不全犬模型的可行性。方法: 选择体质量为(18.3±4.6) kg的健康犬10只。经皮送入加硬导丝,在超声引导下穿破主动脉瓣叶,同时进行球囊扩张瓣叶穿孔处。主动脉瓣上造影检查瓣膜破裂口有无明显的反流,心脏超声检查评估主动脉瓣膜的反流量以及左室射血分数。术后将实验犬饲养两个月,再次复查心脏超声评估主动脉瓣膜的反流量及左心室的功能。结果: 10只实验犬中,除两只在建立急性主动脉瓣膜破裂伤时,导丝穿入心肌导致心包填塞,而放弃继续操作外,其余8只犬手术成功,主动脉瓣膜的瞬时反流量达到(5.2±0.8) ml/s。术后第20天、35天,各有1只实验犬死于心力衰竭,其余6只犬存活到两个月。所有存活实验犬均出现活动耐量的减退。复查心脏超声提示,主动脉瓣瞬时反流量为(8.4±1.2) ml/s,比术后即刻有明显增加;左室射血分数为(42.5±1.1)%,比术后即刻明显降低;左心室容积为(69.5±6.8) ml,左心室壁厚度为(8.6±1.7) mm,比术后即刻有明显的增加,以上各项指标差异均有统计学意义（P<0.05）。结论: 通过经皮穿刺主动脉瓣叶加球囊扩张的方法,建立慢性主动脉瓣关闭不全的犬模型可行,效果理想。     

Percutaneous pulmonary valve implantation in left pulmonary artery branch in a patient with a functional single lung

Percutaneous pulmonary valve technology has had a great impact on patients with congenital and acquired heart disease. In some patients, implantation of a percutaneous pulmonary valve may not be possible due to the morphology of the existing right ventricular outflow tract. In this report, we describe implantation of a Melody transcatheter pulmonary valve in the left pulmonary artery in a patient with acquired right pulmonary artery occlusion and a large right ventricular outflow tract.     

Percutaneous pulmonary valve replacement in a large right ventricular outflow tract: an experimental study

OBJECTIVES: We report our initial experience with percutaneous pulmonary valve replacement in animals with large pulmonary trunks, using a modified percutaneous approach. BACKGROUND: Percutaneous pulmonary valve replacement has recently been introduced, and early clinical experience has been reported. This technique is presently limited to patients with a right ventricular outflow tract no bigger than 22 mm in diameter. METHODS: In seven animals (groups 1 and 3), we implanted a newly designed nitinol stent in the shape of a conduit with a central restriction of its diameter, containing an 18-mm bovine valve, as a one-step procedure. The animals in groups 1 and 3 were sacrificed after valve implantation and after two-month follow-up, respectively. In the second group (n = 3), we expected to percutaneously reduce the diameter of the pulmonary artery. Eight weeks later, we implanted an 18-mm valve mounted in a balloon-expandable stent. These animals were sacrificed after valve implantation. RESULTS: Eight of 10 devices were successfully delivered and were functioning perfectly at the initial evaluation and after two months. We failed to cross the tricuspid valve in two cases. The downsize mechanism allowed the pulmonary diameter to be reduced from 30 to 18 mm, without an impact on right ventricular function in any of the animals. CONCLUSIONS: Non-surgical implantation of a pulmonary valve is possible in ewes with all types of pulmonary trunk, regardless of its size. A "downsize" stent is needed to allow valve implantation in a large trunk. Further refinements will make this technique feasible in humans.     

应用新型介入瓣膜行经导管主动脉瓣置入术的实验研究

目的 探讨应用新型介入瓣膜在实验动物体内行经导管主动脉瓣置入术(TAVI)的可行性,并观察新型介入瓣膜置入后的短期效果.方法 选取健康成年绵羊20只,在全身麻醉及成像造影设备的辅助下,经绵羊一侧颈总动脉置入输送鞘管,于主动脉瓣环处释放新型介入瓣膜.以左心室和主动脉造影及经胸超声心动图观察介入瓣膜的位置和作用.记录术后30 d实验动物的存活情况.结果 所有实验绵羊均置入新型介入瓣膜.15只(75％)存活绵羊的术后造影显示介入瓣膜位置良好,无移位,未影响二尖瓣;冠状动脉开口显影良好,冠状动脉通畅.经胸超声心动图显示5例绵羊存在轻度瓣周漏.术后存活绵羊主动脉瓣反流百分比由术前( 1.25±0.46)％增加至(4.52±3.56)％(P＜0.05).术后主动脉瓣有效瓣口面积、主动脉收缩压、主动脉舒张压、平均主动脉压、左心室收缩压、左心室舒张末压、心率与术前比较差异均无统计学意义(P＞0.05).5只(25％)绵羊于TAVI后30 d内死亡,其中介入瓣膜释放展开后即刻,因左冠状动脉开口堵塞发生心室颤动而死亡1只,术后20 min死于急性心肌梗死1只,术后8和12h死于二尖瓣反流2只,术后26 d死于感染性心内膜炎1只.结论 采用新型介入瓣膜在实验动物体内行TAVI是可行的,短期内安全、有效.     

Bilateral coronary fistulae to pulmonic valve in presence of severe three-vessel coronary artery disease

A 62-year-old man was admitted to the coronary care unit due to anginal pain and palpitations--coronary angiography revealed three-vessel coronary artery disease. The unexpected finding was the presence of coronary to pulmonary artery fistulae bilaterally, from both the proximal RCA and the proximal LAD. Right heart catheterization revealed normal right ventricular and pulmonary artery pressure and absence of hemodynamically significant left to right shunt. The patient underwent a triple coronary bypass including the closure of bilateral fistulae, which were draining into the left sinus of the pulmonary valve. One month after the operation he was in good health and had no complaints. Bilateral coronary artery fistulae is a rare anomaly diagnosed in 0.002-0.0013% of adult coronary angiograms. (Int J Cardiovasc Intervent 1999; 2: 249-251).     

Utilisation of gastric ring systems for pulmonary artery banding: an animal study

OBJECTIVES: Pulmonary artery banding is often required as a first palliative procedure in infants with congenital heart disease and high pulmonary blood flow or to retrain the left ventricle. The purpose of the study was to demonstrate the safety of a gastric banding system as an adjustable pulmonary artery banding in chronic implantation. METHODS: Five ewes underwent implantation of the banding system around the main pulmonary artery through a left thoracotomy. All had functional evaluation with progressive occlusion and opening of the device every two weeks for a total period of three months. Invasive pressure measurements in the right ventricle and aorta were carried out each time. RESULTS: Devices could be implanted easily. Progressive occlusion and re-opening were possible in all animals during each time point. All animals survived throughout the protocol. Retrieval of the device was achieved in all animals. In one, it was challenging because of the presence of a fibrotic reaction around the device. It died because of pulmonary artery perforation before the sacrifice. At autopsy, microscopic examination showed no signs of myocardial fibrosis. CONCLUSIONS: In animals, gastric banding system is a safe and effective implantable device to adjust pulmonary artery diameter over a prolonged period of time. This new device may be a valuable alternative to the repeated conventional pulmonary artery banding needed for ventricular retraining in humans.     

Effects of acute hemodynamic alterations on pulmonic valve motion. Experimental and clinical echocardiographic studies.

The purpose of this study was to assess the effects of acute alterations of the pulmonary circulation on the pulmonic valve echocardiogram. We measured the pulmonic valve opening velocity (PVOV) and right-sided systolic time intervals (right ventricular preejection period-to-right ventricular ejection time ratio [RPEP/RVET] in 22 open-chest dogs subjected to acute hemodynamic alterations produced by inferior vena cava constriction, atrial pacing, isoproterenol infusion and microsphere embolization of the pulmonary artery. We found only fair correlations between PVOV and peak pulmonary artery flow (r = 0.56), right ventricular dp/dt (r = 0.43), stroke volume (r = 0.42), pulmonary artery systolic pressure (r = 0.33) and peak pulmonary artery acceleration (r = 0.31). RVET was shortened by reduced venous return (caval constriction) and by increases in heart rate (atrial pacing and isoproterenol), which resulted in increases in RPEP/RVET that did not correspond well to simultaneous changes in pulmonary artery pressure. In seven patients breathing 10% O2 to raise pulmonary artery pressure acutely, we found no change or a fall in PVOV. Thus, the pulmonic valve echocardiogram is influenced by multiple factors relating to parameters of pulmonary flow and right ventricular contractility, and may be of limited clinical usefulness in predicting pulmonary artery pressures.     

Acceleration of the wavefront of myocardial necrosis by chronic hypertension and left ventricular hypertrophy in dogs

Previous studies have shown that hypertension and left ventricular hypertrophy (HT-LVH) increase completed infarct size. Myocardial infarction progresses in a wavefront of myocardial necrosis from the subendocardium to the subepicardium. We tested two hypotheses: First, HT-LVH accelerates the wavefront of myocardial necrosis when compared with normotensive animals; and second, lowering of arterial pressure by infusing nitroprusside 1 hour after coronary artery occlusion exerts a salutary effect on infarct size. To test these hypotheses, systemic hypertension (mean aortic pressure = 141 +/- 3 mm Hg) and left ventricular hypertrophy (18% increase in left ventricular mass) were induced in dogs using a single-kidney, single-clip model. Seventeen adult mongrel dogs were used as controls. We measured mean aortic pressure, heart rate, left atrial pressure, and myocardial perfusion (microspheres) in several groups of normal and HT-LVH awake dogs. In two groups (normal and HT-LVH), 1 hour of circumflex coronary artery occlusion was followed by 4 hours of reperfusion. In two additional groups (normal and HT-LVH), 3 hours of circumflex coronary artery occlusion was followed by 90 minutes of reperfusion. In another group with HT-LVH, nitroprusside was infused to reduce mean arterial pressure to 100 mm Hg beginning 1 hour after occlusion and was continued for the duration of reperfusion period (HT-LVH + N). Infarct size was assessed using triphenyltetrazolium chloride stain and risk area was determined using postmortem barium angiography. Fifteen of 17 (88%) control animals survived coronary artery occlusion, whereas only 17 of 42 (40%) dogs with HT-LVH survived coronary occlusion (p less than 0.05). Infarct-to-risk ratios in the various layers of the left ventricular wall were determined for survivors in all groups. After 1 hour of coronary occlusion more than twice as much mid-wall and epicardium was infarcted in the HT-LVH group compared with the control group. After 3 hours of coronary occlusion significantly more endocardium, mid-wall, and epicardium was infarcted in the dogs with HT-LVH. In the nitroprusside-treated HT-LVH dogs, the infarct sizes were similar to control animals. From these data we conclude: 1) the rate of infarction is accelerated in animals with HT-LVH; 2) nitroprusside infused 1 hour after coronary artery occlusion and continued throughout the reperfusion period exerts beneficial effect on infarct size when compared with control animals; and 3) acute coronary artery occlusion in animals with HT-LVH is associated with significantly greater mortality when compared with control animals.     

A reversible pulmonary artery band: preliminary experience

Pulmonary artery banding has become an infrequently used surgical technique. However, if a band was developed that could be relieved without the need for open heart surgery, it is likely that pulmonary artery banding would be used more frequently in the management of infants with congenital heart disease. Such a pulmonary artery band was placed in seven 1 week old mongrel puppies by using a loop of an absorbable suture material (Vicryl). One dog died at 2 months as a result of right ventricular failure. The remaining six dogs underwent cardiac catheterization and pulmonary balloon angioplasty at 6 months of age. After measuring pulmonary artery, right ventricular and aortic pressures and performing a right ventricular angiogram, balloon angioplasty of the band site was performed. A 20 mm balloon angioplasty catheter (Medi-Tech) was used in all dogs. Balloon angioplasty decreased right ventricular pressure from 101 +/- 19 to 42 +/- 3 mm Hg (p less than 0.05) and right ventricular systolic outflow tract gradient from 59 +/- 14 to 7 +/- 2 mm Hg (p less than 0.03), and increased the size of the band site from 8.7 +/- 0.03 to 14.9 +/- 0.5 mm (p less than 0.01). All dogs were recatheterized 2 months after angioplasty and were then killed for pathologic evaluation. At follow-up catheterization, right ventricular pressure, right ventricular outflow tract gradient and pulmonary artery size at the band site remained at the values obtained immediately after angioplasty. Postmortem examination demonstrated that there was no evidence of pulmonary artery damage. Although these studies are preliminary, they suggest that a reversible pulmonary artery band can be performed.     

Percutaneous insertion of the pulmonary valve

OBJECTIVES: We report our experience of percutaneous valve insertion in pulmonary position in humans. BACKGROUND: Over the past 40 years, prosthetic conduits have been developed to surgically establish continuity between the right ventricle and the pulmonary artery. However, stenosis and insufficiency of the conduit due to valvular degeneration or panus ingrowth frequently occur, limiting patients' lifespan. Percutaneous stenting of conduits has recently emerged as a technique for delaying surgical replacement, but it creates a pulmonary regurgitation when crossing the valve. METHODS: Seven children and one adult with stenosis and/or insufficiency of the pulmonary graft underwent percutaneous implantation of a bovine jugular valve in pulmonary position. RESULTS: Percutaneous pulmonary valve (PV) replacement was successful in all patients. No complications occurred in early follow-up. Angiography, hemodynamic studies and echocardiography after the procedure showed no significant regurgitation of the implanted valve. Implantation was effective in relieving the obstruction in five patients. All patients showed improvement in their clinical status at the latest follow-up (mean 10.1 months). CONCLUSIONS: Non-surgical insertion of the PV is possible without any major complications. This new technique may have an important role in the management of conduit obstructions and pulmonary regurgitation.     

Factors determining early improvement in mitral regurgitation after aortic valve replacement for aortic valve stenosis: a transthoracic and transesophageal prospective study

BACKGROUND: Mitral regurgitation (MR) is frequently associated with aortic stenosis. Previous reports have shown that coexisting mitral insufficiency can potentially regress after aortic valve replacement. HYPOTHESIS: This study sought to assess the frequency and severity of MR before and after aortic valve replacement for aortic stenosis and to define the determinants of its postoperative evolution. METHODS: For this purpose, 30 adult patients referred for aortic valve surgery underwent pre- and postoperative transthoracic and transesophageal echocardiography and color Doppler examination. RESULTS: Mean preoperative left ventricular ejection fraction was 57 +/- 16% and remained unchanged postoperatively. Preoperative MR was usually mild to moderate and correlated with aortic stenosis severity and left ventricular systolic dysfunction. The color Doppler mitral regurgitant jet area significantly decreased during the postoperative period (p = 0.016) as left ventricular loading conditions returned to normal, suggesting an early decrease of the functional part of MR. On the other hand, the mitral regurgitant jet width at the origin remained unchanged. Statistical analysis found pulmonary artery pressure (p = 0.02) an d indexed left ventricular mass (p = 0.009) to be preoperative predictive factors of postoperative MR improvement. Predictive factors of postoperative MR severity were left atrial diameter (p = 0.02), pulmonary artery pressure (p = 0.003), and the presence of mitral calcifications (p = 0.004). CONCLUSION: In our cohort of patients with normal left venticular ejection fraction, the majority of moderate MR, associated with severe aortic stenosis, regresses early after aortic valve replacement. Mitral calcifications and/or left atrial dilation seem to be predictive factors of fixed MR.