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功能性磁共振成像(心室和心房)的最新病理生理学概述

Updated pathophysiological overview of functional MR (ventricular and atrial).

作者信息

Akashi Jun, Otsuji Yutaka, Nishimura Yosuke, Levine Robert A, Kataoka Masaharu

机构信息

Second Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.

Department of Cardiovascular Medicine, Hagiwara Central Hospital, 1-10-1 Hagiwara, Yahatanishiku, Kitakyushu, 806-0059, Japan.

出版信息

Gen Thorac Cardiovasc Surg. 2025 Jan;73(1):1-11. doi: 10.1007/s11748-024-02047-5. Epub 2024 Jun 10.

Abstract

Basic mechanism of ventricular functional mitral regurgitation (FMR) is subvalvular tethering. Left ventricular (LV) dilatation, in association with mitral valve (MV) annular dilatation, causes outward displacement of papillary muscles (PMs), which abnormally pulls or tethers MV leaflets, resulting in MV tenting, reduction in leaflets coaptation and MR. Because surgical annuloplasty does shorten distance between anterior and posterior MV annuli to improve coaptation but does not address this subvalvular tethering, ventricular FMR frequently persists or recurs in the chronic stage after surgical annuloplasty. This high incidence of persistent/recurrent MR requires additional procedures to reduce subvalvular tethering. Although patients occasionally show marked improvements after annuloplasty with surgical tethering reduction procedures such as PM approximation, evidence to support benefits of such surgery is limited, requiring further trials. Recently, MV adaptation or MV leaflets tissue growth associated with LV dilatation attracts attention. Patients with larger MV leaflets with significant LV dilatation/dysfunction show less MV tethering and MR compared to those with smaller MV leaflets but with similar LV remodeling, suggesting the protective or beneficial role of MV leaflets tissue growth against LV remodeling. The MV leaflets tissue growth has the potential to lead to novel strategies of treatment for ventricular FMR. It is well known that atrial FMR is frequent in patients with left atrial dilatation, typically in those with isolated atrial fibrillation. The degree of atrial FMR is usually mild, even when it is present, and occasionally moderate, and severe atrial FMR is really rare. It is known that only severe regurgitation causes heart failure in primary MR, resulting in description on indications of surgery or intervention for only severe MR in current guidelines. Therefore, this atrial FMR up to moderate degree did not attract attention for a long time. However, recent studies have shown that patients with only moderate atrial FMR develop severe heart failure, suggesting more aggressive indication of MV surgery or intervention for "moderate" regurgitation in patients with atrial FMR. Therefore, atrial FMR is now recognized highly important. The unveiled malignant nature of atrial FMR arises many questions, including (1) why patients with only moderate atrial FMR develop heart failure? (2) do patients with mild atrial FMR develop heart failure or not?, and many others. Atrial FMR seems even more mysterious after the unveiling of its significance.

摘要

心室功能性二尖瓣反流(FMR)的基本机制是瓣下牵拉。左心室(LV)扩张,伴二尖瓣(MV)环扩张,导致乳头肌(PMs)向外移位,异常牵拉或系住MV瓣叶,导致MV帐篷样改变、瓣叶对合减少和MR。由于手术瓣环成形术确实缩短了MV前后瓣环之间的距离以改善对合,但并未解决这种瓣下牵拉问题,因此心室FMR在手术瓣环成形术后的慢性期经常持续存在或复发。这种持续性/复发性MR的高发生率需要额外的手术来减少瓣下牵拉。尽管患者在进行瓣环成形术并结合如PM靠拢等手术性牵拉减少手术偶尔会有明显改善,但支持此类手术益处的证据有限,需要进一步试验。最近,与LV扩张相关的MV适应性或MV瓣叶组织生长引起了关注。与MV瓣叶较小但LV重塑相似的患者相比,MV瓣叶较大且LV明显扩张/功能障碍的患者MV牵拉和MR较少,提示MV瓣叶组织生长对LV重塑具有保护或有益作用。MV瓣叶组织生长有可能带来治疗心室FMR的新策略。众所周知,左心房扩张的患者,尤其是孤立性房颤患者,心房FMR很常见。心房FMR的程度通常较轻,即使存在也偶尔为中度,严重的心房FMR确实罕见。已知在原发性MR中只有严重反流会导致心力衰竭,因此当前指南中仅针对严重MR给出手术或干预指征的描述。因此,这种中度以下的心房FMR长期以来未受到关注。然而,最近的研究表明,仅有中度心房FMR的患者会发生严重心力衰竭,提示对于心房FMR患者的“中度”反流,MV手术或干预的指征更积极。因此,心房FMR现在被认为非常重要。心房FMR所揭示的恶性本质引发了许多问题,包括(1)为什么仅有中度心房FMR的患者会发生心力衰竭?(2)轻度心房FMR的患者是否会发生心力衰竭?等等。在揭示其重要性之后,心房FMR似乎更加神秘。

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