Late diastolic mitral regurgitation

Late diastolic mitral regurgitation (diastolic backflow of blood from the left ventricle to the left atrium at the end of left-ventricular diastole) is registered by Doppler echocardiography in patients with acquired heart defects and dilated cardiomyopathy. This phenomenon is based on the appearance at the end of left-ventricular diastole of the left ventricle/left atrium pressure gradient which is opposite to a normal relationship. Late diastolic regurgitation is more often encountered in patients with incompetence of the mitral and aortic valves. It is caused by disturbances of the work of the left heart and of kinetics of the mitral valve in relatively low frequency of cardiac contractions and is encountered in sinus rhythm and atrial fibrillation, and does not depend on the value of the transmural diastolic gradient. The clinical significance of mitral regurgitation remains unclear.     

Echocardiographic quantitation of mitral regurgitation

Mitral valve regurgitation is a common valvular problem, particularly in developing nations. It causes significant morbidity and mortality, especially if the severity of valve regurgitation is underestimated. Echocardiography plays a significant role in the diagnoses, serial follow-up and management of patients with valvular heart disease. However, precise quantitation of the severity of mitral regurgitation is a crucial element in the therapeutic decisions for managing mitral regurgitation. An accurate assessment of the severity of mitral regurgitation allows for optimal timing of surgical intervention, culminating in improved patient outcomes. This review provides a systematic approach to the quantitation of mitral regurgitation using the echocardiography and Doppler methodologies that are available in the modern noninvasive imaging and hemodynamic laboratory. Additional, novel and evolving noninvasive imaging modalities are reviewed briefly.     

Echocardiographic quantitation of mitral regurgitation

Mitral valve regurgitation is a common valvular problem, particularly in developing nations. It causes significant morbidity and mortality, especially if the severity of valve regurgitation is underestimated. Echocardiography plays a significant role in the diagnoses, serial follow-up and management of patients with valvular heart disease. However, precise quantitation of the severity of mitral regurgitation is a crucial element in the therapeutic decisions for managing mitral regurgitation. An accurate assessment of the severity of mitral regurgitation allows for optimal timing of surgical intervention, culminating in improved patient outcomes. This review provides a systematic approach to the quantitation of mitral regurgitation using the echocardiography and Doppler methodologies that are available in the modern noninvasive imaging and hemodynamic laboratory. Additional, novel and evolving noninvasive imaging modalities are reviewed briefly.     

Diastolic mitral regurgitation in atrioventricular block

Diastolic mitral block was revealed by ++Doppler echocardiography in patients with atrioventricular block degree I, II and III in atrial flutter. The leading mechanism in pathogenesis of diastolic mitral regurgitation lies in delayed contraction of the left ventricle in relation to the left atrium causing incomplete closure of mitral cusps. Other factors contributing to diastolic mitral insufficiency involve overloading of the left ventricle and rigidity of its myocardium. All the patients with atrioventricular block and diastolic mitral regurgitation showed tricuspid diastolic regurgitation. Diastolic mitral regurgitation induces volumetric overloading of the left atrium.     

Current surgical management of mitral regurgitation

From Walton Lillehei, who performed the first successful open mitral valve surgery in 1956, until the advent of robotic surgery in the 21st Century, only 50 years have passed. The introduction of the first heart valve prosthesis, in 1960, was the next major step forward. However, correction of mitral disease by valvuloplasty results in better survival and ventricular performance than mitral valve replacement. However, the European Heart Survey demonstrated that only 40% of the valves are repaired. The standard procedures (Carpentier's techniques and Alfieri's edge-to-edge suture) are the surgical basis for the new technical approaches. Minimally invasive surgery led to the development of video-assisted and robotic surgery and interventional cardiology is already making the first steps on endovascular procedures, using the classical concepts in highly differentiated approaches. Correction of mitral regurgitation is a complex field that is still growing, whereas classic surgery is still under debate as the new era arises.     

经食管超声心动图在二尖瓣修复术中的应用

目的　探讨经食管超声心动图 (TEE)在二尖瓣反流性病变修复术中的指导作用。方法　对 19例二尖瓣反流 (MR)患者 ,体外循环 (CPB)前及修复术后 ,应用TEE评价二尖瓣结构的异常。在相同的仪器条件和相近的血流动力学状态下 ,以实时目测法估测MR。结果　CPB前TEE检查纠正术前诊断 1例。CPB前MR(3 .4± 0 .5 )级 ,修复后残余MR(1.2± 1.0 )级 (P <0 .0 0 0 1)。 2例因残余MR 3级 ,再次转机行二尖瓣替换术。17例修复术患者出院前经胸超声心动图 (TTE)示残余MR与术中TEE残余反流量无显著性差异 [(0 .9± 0 .7)级vs (0 .9± 0 .8)级 ,P >0 .0 5 ]。后叶病变修复效果明显优于前叶。结论　TEE在二尖瓣修复术前后提供了较为可靠的二尖瓣结构和血流的信息 ,以指导手术治疗。实时目测法半定量评估MR是术中可靠且实用的方法     

Current surgical management of mitral regurgitation

From Walton Lillehei, who performed the first successful open mitral valve surgery in 1956, until the advent of robotic surgery in the 21st Century, only 50 years have passed. The introduction of the first heart valve prosthesis, in 1960, was the next major step forward. However, correction of mitral disease by valvuloplasty results in better survival and ventricular performance than mitral valve replacement. However, the European Heart Survey demonstrated that only 40% of the valves are repaired. The standard procedures (Carpentier’s techniques and Alfieri’s edge-to-edge suture) are the surgical basis for the new technical approaches. Minimally invasive surgery led to the development of video-assisted and robotic surgery and interventional cardiology is already making the first steps on endovascular procedures, using the classical concepts in highly differentiated approaches. Correction of mitral regurgitation is a complex field that is still growing, whereas classic surgery is still under debate as the new era arises.     

运用二尖瓣开放面积测量软件探讨二尖瓣反流的病因机制

目的 本研究在实时三维超声心动图基础上,运用自主研制的二尖瓣开放面积测量软件分析二尖瓣瓣膜在正常和病理状态下的开放规律,并进行量化评估,旨在探讨二尖瓣关闭不全的病因机制。方法 2005年5月至2007年12月上海儿童医学中心心脏中心收治的29例二尖瓣中度反流儿童作为病变组,另选取正常儿童28例作为对照组。运用Philips Sonos 7500型超声诊断仪和配置的实时三维超声探头,探头频率2～4 MHz。将获取的全容积图像导入自主研发的PC工作站,在Matlab 7.0.0.19920（R14）平台上将Dicom图像格式转换为bmp图像格式。通过自主研发的二尖瓣瓣膜开放面积测量软件VolEdit.exe1.0.0.1,采用人机交互模式逐帧测量一个心动周期中每一个时间点的瓣膜开放面积,记录测量结果。最后在Matlab 7.0.0.19920（R14）平台上,将二尖瓣瓣膜开放面积数值输入,自动生成一个心动周期中二尖瓣瓣膜开放面积曲线图。计算机自动计算并保存以下参数的数值：瓣膜开放斜率最大的点（G点）、G点至峰值的时间间期（Int1）、峰值至瓣膜关闭的时间间期（Int2）、瓣膜开放间期（Int3）、瓣膜开放最大斜率（α）,其中Int3= Int1 + Int2。运用SPSS10.0软件进行统计学分析。结果 病变组的G点至峰值的时间间期、瓣膜开放间期和瓣膜开放最大斜率与对照组比较差异有统计学意义;具体表现为：瓣膜开放持续时间延长［（0.631±0.167）个心动周期,（0.573±0.087）个心动周期,P＜0.05］;瓣膜开放至最大面积所需时间延长［（0.166±0.109）个心动周期,（0.079±0.062）个心动周期,P＜0.05］;瓣膜开放最大斜率降低［（7.15±2.72）,（13.20±4.57）,P＜0.05］。病变组的瓣膜开放斜率最大点和瓣膜开放最大面积及瓣膜关闭的时间间期与对照组间比较差异无统计学意义。结论 二尖瓣反流患儿二尖瓣瓣膜的异常运动与左心室心腔扩大、瓣下乳头肌相对位置改变以及张力装置对瓣膜牵拉力度和角度均发生改变有关,这是二尖瓣发生反流的重要因素。     

Duplex pulsed Doppler echocardiography in mitral regurgitation

The accuracy of duplex pulsed Doppler echocardiography (d-PDE) for detecting mitral regurgitation was evaluated in 35 patients undergoing d-PDE, cardiac auscultation, and left ventriculography. With three transducer positions, the overall d-PDE sensitivity was 95%, specificity was 100%, positive predictive value was 100%, negative predictive value was 94%, and diagnostic accuracy was 97% compared with ventriculography. This technique was superior to auscultation (sensitivity 74%, specificity 94%, positive predictive value 93%, negative predictive value 75%, diagnostic accuracy 83%). No false-positive d-PDE results occurred, but discordant false-negative results occurred frequently among the three transducer positions. If discordant negative results are considered to be false negative, then d-PDE is both sensitive and specific when mitral regurgitation is defined as systolic spectral broadening in any one transducer position.     

An alternative treatment approach to mitral regurgitation

This article aims to increase knowledge and understanding of mitral valve regurgitation to assist nurses in providing effective patient care and support the treatment options available. It focuses on the MitraClip, a procedure to repair the mitral valve using a percutaneous approach.     

Radionuclide quantification of mitral and aortic regurgitation

Abstract. Gated equilibrium bloodpool scintigraphy was used to obtain the ratio of left and right ventricular stroke counts (end-diastolic minus end-systolic counts within ventricular areas of interest), the radionuclide equivalent of stroke volumes. This ratio or stroke count index (SCI) should be unity in normal subjects and increased in patients with aortic or mitral regurgitation, when left ventricular stroke output rises to compensate for regurgitant flow. Results of this non-invasive method were compared with semiquantitative angiographic grading of mitral (1 to 4+) or aortic (1 to 3+) regurgitation in ninety-seven patients. We found a SCI of 1.15 ± 0.18 (SD) in thirty-six control subjects without evidence of mitral or aortic regurgitation at cardiac catheterization. Subsequently, a ratio of 1.50 was chosen as the upper limit of normal for the analysis of thirty-seven patients with mitral regurgitation and twenty-four patients with aortic regurgitation. Clearly, elevated SCI values were obtained in the presence of grade 3 and 4 mitral regurgitation (eighteen out of twenty patients) and of grade 2 and 3 aortic regurgitation (seventeen out of eighteen patients). Only two out of seventeen subjects with grade 1 or 2 mitral incompetence had an elevated SCI, while none of six subjects with grade I aortic regurgitation had an abnormal SCI. If these lesser degrees of valvular incompetence are considered of minor significance, overall sensitivity of the radionuclide method in our patient population was 92%, specificity 95%. Occasional discrepancies between SCI and angiographic severity of left-sided valvular regurgitation are probably a result of methodological limitations. We could not demonstrate any relation with global left ventricular function as measured from the radionuclide ejection fraction. We conclude that the SCI may be used as a non-invasive tool for diagnosis and management of patients with valvular heart disease, both before and after interventions.     

瓣环扩大在功能性二尖瓣返流机制中的作用

目的探讨瓣环扩大在功能性二尖瓣返流机制中的作用。方法应用超声心动图检查房颤组(20例)、返流组(30例)及正常组(20例)的心脏,测量二尖瓣返流比例、左室射血分数(EF)、左室大小、球形度、收缩期瓣环(MA)面积、收缩期后乳头肌与二尖瓣前瓣环的距离(PPMAMA)。结果房颤组左室大小、球形度、EF、PPMAMA和正常组相比没有统计学差异,但收缩期MA面积较正常组明显扩大,并与返流组相似,分别为(5.3±1.1)cm2、(7.4±1.5)cm2、(8.0±2.0)cm2,但房颤组二尖瓣返流量明显小于功能性二尖瓣返流组,分别为(12±7)%和(30±14)%。结论单纯瓣环的扩张似乎并不引起中或重度二尖瓣返流。     

二尖瓣环成形术后缺血性二尖瓣反流再发的机制探讨

目的通过对二尖瓣形态学改变与二尖瓣反流程度相关性的研究，探讨二尖瓣环成形术后缺血性二尖瓣反流的再发机制。方法连续对31例行二尖瓣环成形术的缺血性二尖瓣反流患者手术前后进行标准的超声心动图检查。观察指标包括：二尖瓣关闭点心尖方向、前后方向位移，前后叶的关闭角度和活动度。结果31例患者二尖瓣环成形术后6例再发二尖瓣反流。后叶受牵拉增强是术后缺血性二尖瓣反流的独立决定因素。结论二尖瓣环成形术后的缺血性二尖瓣反流再发是前后叶同时受累，后叶受到的牵拉程度明显增强起主要的决定作用。     

Etiology and short-term prognosis of severe mitral regurgitation

Purpose To describe the etiology and to document the course of severe mitral regurgitation (MR). Methods Prospective registry of 272 patients diagnosed with chronic severe MR in an echocardiographic study. Results Mean age was 70.2 ± 13.8 years and 143 patients were women (53%). The most frequent causes of regurgitation were rheumatic disease (72 patients; 26%), ischemic etiology (58; 21%), valve prolapse (57; 21%), and dilated cardiomyopathy (49; 18%). A total of 43 patients (16%) died during follow-up (mean 0.9 ± 0.3 years, total 2,785 patient-months): 30 from cardiac causes, 9 from non-cardiac causes, and 4 from unknown causes. Actuarial transplant-free survival was 87% at 6 months, and 81% at 1 year. Renal disease, previous stroke, ischemic etiology, and poor left ventricular ejection fraction were independent predictors of mortality. Conclusions Rheumatic disease is still the main cause of severe MR in Spain. Patients with severe MR have advanced age and present poor short-term prognosis.     

二尖瓣关闭不全动物模型的研究进展

二尖瓣装置在解剖结构或功能上的异常造成左心室收缩时左心室内血液部分反流到左心房即称为二尖瓣关闭不全(MR)。二尖瓣装置由二尖瓣环、瓣叶、腱索及其所连接的乳头肌等所组成。MR动物模型的创建对于我们进一步研究MR的发病机制、进行性损害机制及治疗效果有着重要的意义。本文综述了目前国内外MR动物模型的建立及其手术治疗方法。     

Aberrantly inserted chordae tendineae without significant mitral regurgitation

Aberrantly inserted chordae tendineae in the left atrial side are a rare find. We report here the case of a young patient with aberrantly inserted chordae tendineae not causing significant mitral regurgitation. Because the patient remained asymptomatic and the anomalous chord of the left atrium could be considered within normal human anatomic variation, the authors decided to only monitor the patient's condition for the time being. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 42:57–58, 2014     

Left heart longitudinal deformation analysis in mitral regurgitation

In mitral regurgitation (MR), left atrium (LA) and left ventricle (LV) undergo remodeling even if the patient is asymptomatic. The aim of our study was to identify the best echo index that correlates with MR severity in asymptomatic patients affected by MR. We enrolled 150 MR patients (50: mild, 50: moderate, 50: severe), asymptomatic for exertional dyspnea and 50 healthy controls. MR was graded using Doppler quantitative method. All underwent standard and Speckle Tracking Echocardiography (STE) with analysis of global peak atrial longitudinal strain (PALS), LV longitudinal strain (LS) and global atrio-ventricular strain (GAVS). LA dimensions showed significant differences between the groups while LV end-diastolic diameter did not significantly differ, although having a slight increase. PALS was slightly higher in patients with mild MR, while decreased in moderate and, mainly, in severe MR (controls 37.4?±?12.2%, mild MR 38.2?±?9%, moderate MR 29.1?±?9%, severe MR 19.8?±?10.6%, p?<?0.0001 by ANOVA); the same was found for GAVS (56.1?±?13%, 57.6?±?9.7%, 48.2?±?9% 39?±?9.4%, p?<?0.0001 by ANOVA). LV LS showed a tendency for gradual reduction in the three groups. In multivariate analysis, PALS and GAVS were far superior than GLS as predictors of MR groups. PALS emerged as an added value to the LA indexed volumes as predictor of MR severity. STE-derived PALS and GAVS emerged as promising tools to investigate heart longitudinal function in patients with chronic MR and no symptoms. PALS can represent a surplus in the prediction of severity of MR, in addition to the assessment of LA volumes.     

二尖瓣反流的超声多普勒模拟显像

目的模拟二尖瓣反流的超声Doppler成像。方法据圆形轴对称自由紊动射流模型,利用超声成像模拟软件FieldⅡ模拟简化的二尖瓣反流的三种情况:①完全正向射流;②中心为正向射流,边缘为负向反流;③上半部分为正向射流,下半部分为负向反流。获得不同情况下的RF信号,然后采用脉冲多普勒方法估计血流速度,并对RF信号进行经典谱分析。结果得到了三种情况不同成像角度的RF信号,并估计出血流速度,获得彩色多普勒显像以及RF信号的频谱图。随着超声波束与血流角度的减小,检测到速度增加。结论模拟结果表明不同情况的血流都得到了很好的成像模拟,对于临床二尖瓣反流评价具有一定的指导意义。