Contemporary Evaluation and Clinical Treatment Options for Aortic Regurgitation

Abstract

Aortic regurgitation (AR) is the third most frequent form of valvular disease and has increasing prevalence with age. This will be of increasing clinical importance with the advancing age of populations around the globe. An understanding of the various etiologies and mechanisms leading to AR requires a detailed understanding of the structure of the aortic valve and aortic root. While acute and chronic AR may share a similar etiology, their hemodynamic impact on the left ventricle (LV) and management are very different. Recent studies suggest current guideline recommendations for chronic disease may result in late intervention and suboptimal outcomes. Accurate quantitation of ventricular size and function, as well as grading of the severity of regurgitation, requires a multiparametric and multimodality imaging approach with an understanding of the strengths and weaknesses of each metric. Echocardiography remains the primary imaging modality for diagnosis with supplemental information provided by computed tomography (CT) and cardiac magnetic resonance imaging (CMR). Emerging transcatheter therapies may allow the treatment of patients at high risk for surgery, although novel methods to assess AR severity and its impact on LV size and function may improve the timing and outcomes of surgical intervention.

Keywords: aortic regurgitation; echocardiography; transcatheter aortic valve replacement.

Figure 1

Anatomy of the Aortic Valve. In this figure, the anatomy of the aortic valve complex is shown. The aortic valve is composed of three cusps attached to the root in a semilunar fashion with their nadir of coaptation at the basal ring, representing the level of the annulus, and highest point of attachment of the leaflet commissures at the sinotubular junction. The atrioventricular (AV) node is typically located on the floor of the right atrium just posterior (post) and inferior to the membranous septum (blue shaded region). The atrioventricular (AV) node and bundle then courses on the top of the muscular septum under the membranous septum (blue area), where it divides into the left and right bundles. Abbreviations: ant, Anterior; IVS, interventricular septum; LM, left main coronary artery; RCA, right coronary artery. (Reproduced with permission from Hahn RT, Nicoara A, Kapadia S, Svensson L, Martin R. Echocardiographic Imaging for Transcatheter Aortic Valve Replacement. J. Am. Soc. Echocardiogr. [6].

Figure 2

Anatomy of the aortic root. The aortic root is defined as the portion of the aorta between the basal ring within the left ventricle (green line, panel (A)) and the sinotubular junction (gray circle, panel (B)). The root is described as containing three circular rings: virtual ring at the basal attachments of the leaflets (green line/area), the crown-like ring composed of the semilunar attachments of the leaflets (red-blue-yellow lines) and ring at the level of the STJ. (Reproduced from Kasel AM, Cassese S, Bleiziffer S, Amaki M, Hahn RT, Kastrati A, Sengupta PP. Standardized imaging for aortic annular sizing: implications for transcatheter valve selection. JACC Cardiovasc. Imaging [8].

Figure 3

Carpentier Classification of Etiologies of Aortic Regurgitation. Aortic regurgitation can be classified by the etiology of aortic regurgitation as: leaflet malcoaptation/perforation (Type I), excessive leaflet motion (Type II), or restricted leaflet motion (Type III). Type I disease can be further subclassified into the location of the aortic root dilatation: sinotubular junction, sinuses of Valsalva, or ventriculoarterial junction. (After Zoghbi WA, Adams D, Bonow RO, et al. Recommendations for Noninvasive Evaluation of Native Valvular Regurgitation: A Report from the American Society of Echocardiography Developed in Collaboration with the Society for Cardiovascular Magnetic Resonance. J Am Soc Echocardiogr. [10]).

Figure 4

Aortic valve repair techniques. A prolapsed cusp is repaired with central plication (A), triangular resection (B), Trusler stitch (C), or free-edge resuspension (D). A perforated cusp is repaired with patch closure using pericardium (E). Annular dilation of aortic valve causing central regurgitation is repaired with plication stitches placed in the aortic wall at each commissure (F). (Reproduced with permission from Yang LT, Michelena HI, Maleszewski JJ, et al. Contemporary Etiologies, Mechanisms, and Surgical Approaches in Pure Native Aortic Regurgitation. Mayo Clin. Proc. [11].