Epidemiology and Pathophysiology of Mitral Valve Prolapse New Insights Into Disease Progression, Genetics, and Molecular Basis
Epidemiology and Pathophysiology of Mitral Valve Prolapse New Insights Into Disease Progression, Genetics, and Molecular Basis
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DOI：
10.1161/circulationaha.113.006702
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发表时间：
2014-05-27
期刊：
影响因子：
37.8
通讯作者：
Vasan, Ramachandran S.
中科院分区：
文献类型：
--
作者：
Delling, Francesca N.;Vasan, Ramachandran S.
Dling和Vasan将MVP 2159的流行病学和病理生理学称为典型脱垂，而叶增厚程度较轻的脱垂称为非典型脱垂。26经胸超声心动图(TTE)可能不能充分显示整个MV解剖结构。在解剖学上，MV的后叶和前叶各可分为3节。Carpentier公认的命名法描述了3个后叶扇贝，外侧(P1)、中部(P2)和内侧(P3)，以及3个前节，外侧(A1)、中部(A2)和内侧(A3；图1D)。27、28大多数脱垂病例累及后中部扇贝，在长轴TTE图像上很容易辨认出来(图1A)。然而，后外侧扇贝(P1)在长轴图像上看不清楚，但在心尖四腔切面上显示最好。如上所述，四腔切面上叶移位不应被视为脱垂的诊断。因此，TTE可以确定MVP的诊断，但可能不能排除所有扇贝脱垂。虽然Carpentier的命名是基于小叶的凹陷，但在Duran分类中，扇贝是根据索状附着物来分组的。29具体地说，前叶分为2个节段(A1和A2)，后叶分为4个节段(P1、PM1、P2和PM2)。A1、P1和PM1段附着于前外侧乳头肌，A2、P2和PM2段附着于后内侧乳头肌。经修改的Carpentier分类30是Carpentier和Duran命名法的组合。虽然Duran和改良的Carpentier分型在解剖学上比经典的Carpentier分型更精确，但它们的应用却不那么广泛。二维经食道超声心动图(TEE)综合考虑了几个平面的成像，在识别脱垂的MV节段方面更为有效(图1B)。28三维TEE还有一个额外的优势，即模拟外科医生的MV视角，将主动脉瓣置于11点位置(图1D)，并已成为术中设置的重要工具。31心脏磁共振(CMR)是一种新的、但尚未广泛应用的无创性成像方法，以2D TTE为金标准，该方法诊断MVP的灵敏度和特异度均为100%(图2A)。32此外，CMR还可以使用相衬速度图对MR进行量化。33由于CMR能可靠地定量测定脑室容量和功能，已成为MVP相关中重度MR患者随访和手术决策的重要临床工具。34最后，CMR通过延迟Gd增强的三维图像采集提供了改进的空间分辨率，从而为MV及其相连的心肌的生物学提供了新的洞察力。32当两个相邻隔室的Gd排泄动力学不同时，就会发生这种增强，因此随着时间的推移，一个隔室比另一个隔室增强得更多。这是描绘梗死和疤痕心肌的有力工具，心肌比活组织分泌Gd的速度要慢。在MVP患者的MV和乳头肌尖端都显示了Gd的增强，但在正常对照组中没有显示(图2B)。32据推测，MVP中的乳头肌是通过下垂的小叶施加的重复牵引而改变的，35这已被实验证明可以降低心律失常的阈值。36尽管24小时动态心电监护仪上更频繁的复杂心律失常有…
Delling and Vasan Epidemiology and Pathophysiology of MVP 2159 called classic prolapse, whereas prolapse with lesser degrees of leaflet thickening is regarded as nonclassic prolapse. 26 Transthoracic echocardiography (TTE) may not adequately visualize the entire MV anatomy. Anatomically, the posterior and anterior leaflets of the MV each may be divided into 3 sections. Carpentier’s widely recognized nomenclature describes 3 posterior leaflet scallops, the lateral (P1), middle (P2), and medial (P3), and 3 anterior segments, the lateral (A1), middle (A2), and medial (A3; Figure 1D). 27, 28 Most cases of prolapse involve the posterior middle scallop, which is easily identified on long-axis TTE images (Figure 1A). However, the posterior lateral scallop (P1) is not clearly seen on long-axis images but is best visualized in the apical 4-chamber view. As noted above, superior leaflet displacement in a 4-chamber view should not be regarded as diagnostic of prolapse. Thus, TTE can confirm the diagnosis of MVP but may not be able to exclude prolapse of all scallops. Although the Carpentier nomenclature is based on leaflet indentation, in the Duran classification, scallops are grouped on the basis of chordal attachments. 29 Specifically, the anterior leaflet is divided into 2 segments (A1 and A2) and the posterior into 4 segments (P1, PM1, P2, and PM2). Segments A1, P1, and PM1 attach to the anterolateral papillary muscle, and segments A2, P2, and PM2 attach to the posteromedial papillary muscle. The modified Carpentier classification30 is a combination of the Carpentier and Duran nomenclatures. Although the Duran and modified Carpentier classifications are anatomically more precise than the classic Carpentier scheme, they are less widely used. By taking into account several planes of imaging, 2D transesophageal echocardiography (TEE) is more effective in identifying prolapsing MV segments (Figure 1B). 28 Threedimensional TEE has the additional advantage of simulating the surgeon’s view of the MV, with the aortic valve at the 11 o’clock position (Figure 1D), and has become an essential tool in the intraoperative setting. 31Cardiac magnetic resonance (CMR) represents a novel, albeit still not widely used, noninvasive imaging method that identifies MVP with a sensitivity and specificity of 100% with 2D TTE used as the gold standard (Figure 2A). 32 In addition, CMR can quantify MR using phase-contrast velocity mapping. 33 Because CMR can reliably provide quantitative determination of ventricular volumes and function, it is becoming an important clinical tool for following up patients with MVP-related moderate to severe MR and for surgical decision making. 34 Finally, CMR provides novel insight into the biology of the MV and its linked myocardium through improved spatial resolution provided by 3-dimensional acquisition of images with delayed gadolinium enhancement. 32 Such enhancement occurs when the kinetics of gadolinium excretion is different in 2 adjacent compartments so that over time 1 compartment enhances more than the other. This has been a powerful tool for delineating infarcted and scarred myocardium, which excrete gadolinium more slowly than viable tissue. The presence of gadolinium enhancement has been shown in both the MV and in papillary muscle tips in patients with MVP but not in normal control subjects (Figure 2B). 32 It has been speculated that the papillary muscle is altered in MVP by repetitive traction exerted by the prolapsing leaflets, 35 which has been shown experimentally to lower the threshold for arrhythmias. 36 Although more frequent complex arrhythmia on 24-hour ambulatory Holter monitor has …