En Face View of the Mitral Valve: Definition and Acquisition

Anesth Analg. 2012 October;115:779-84
Mahmood F, et al.

Abstract

A 3-dimensional echocardiographic view of the mitral valve, called the "en face" or "surgical view," presents a view of the mitral valve similar to that seen by the surgeon from a left atrial perspective. Although the anatomical landmarks of this view are well defined, no comprehensive echocardiographic definition has been presented. After reviewing the literature, we provide a definition of the left atrial and left ventricular en face views of the mitral valve. Techniques used to acquire this view are also discussed.

Review

by Alexander Wolf M.D.

Since its introduction in 1993, various 3d TEE imaging modes have become invaluable to the intraoperative planning of mitral valve repair. Perhaps the most valuable view of the mitral valve in this setting is known as the "en face" or "surgeon's" view. This view closely resembles what the surgeon sees when he or she approaches the mitral valve via a left atrial incision. Although this view is widely used and described, standardized definitions of what comprised it were lacking. In this technical communication, Mahmood et al. propose a standardized definition of the en face view of the mitral valve and some considerations in modes of 3d acquisition.

The proposed definition of this view describes a forward facing view of the mitral valve from the left atrium. For orientation purposes, the aortic valve is positioned at 12 o'clock. From this perspective, the left atrial appendage will be at 9 o'cock, as will the anterolateral commissure. The posteromedial commissure will appear at 3 o'clock, with the line of coaptation running from 9 o'clock to 3 o'clock. The leaflet below this line is the posterior leaflet of the mitral valve, with the P1, P2, and P3 scallops appearing from left to right. Above the commissural line is the anterior leaflet, with its corresponding segments. One important additional landmark is the coronary sinus, which can be seen running posteriorly to the posterior leaflet from approximately 9 o'clock to 3 o'clock.

The article also describes rotation of this image 180 degrees in the horizontal plane, so that the mitral valve is seen from the perspective of the left ventricle. This vantage point affords a good view of the left ventricular outflow tract and the subvalvular apparatus including the chordae. Sometimes additional perspectives obtained by tilting the en face view may allow better appreciation of prolapsing or flail segments.

The final section of the article deals with recommendations for image acquisition. The three 3d modes described are live 3d, 3d zoom, and full volume 3d. The first two are live imaging modes where transducer movement will be reflected in the image, whereas full volume 3d is a gated acquisition mode, where multiple subvolumes (called "frustums") are stitched together to create a recorded image.

Mahmood et al. hope that a standardized definition of the en face view of the mitral valve will improve communication among cardiologists, anesthesiologists, and surgeons in the setting of mitral valve repair. Additionally, the authors give helpful tips about precisely how to acquire high quality images.