Value and Limitations of Transesophageal Echocardiography in Mitral Valvular Prosthesis

Abstract

Assessment of prosthetic valve function, a frequently encountered challenge to the clinician, is often confounded by superimposed cardiovascular problems such as ventricular dysfunction, multivalvular disease, and ischemic heart disease. Fluoroscopy, phonocardiography, and echocardiography have been tools used in the evaluation of normal and abnormal prosthetic valve function over the past several years [1–4]. The advent of Doppler echocardiography has given a big boost to noninvasive hemodynamic assessment of prosthetic valve function [5]. There are now available normal values for most prosthetic valves [6]. Increased gradients and prolonged half-times with decreasing valve areas are characteristically seen in prosthetic valve stenosis. This hemodynamic assessment is now possible noninvasively by transthoracic Doppler interrogation of the valve. Aortic prosthesis dysfunction due to regurgitation can be detected and semiquantitated both by pulsed/continuous wave Doppler and color flow imaging. The usefulness of transthoracic two-dimensional echocardiography as well as Doppler and color flow imaging in assessment of mitral prosthetic function is limited due to attenuation and flow masking behind the nonbiologic material of the prosthesis [7, 8]. Detection of other potential complications such as mural thrombus in the atrium/atrial appendage, vegetations, and ring abscesses via the transthoracic route is limited due to acoustic shadowing by the prosthetic valve material.