In Vitro Prosthetic Valve Studies Utilizing Echocardiography

Abstract

An in vitro model for studying the echocardiographic M-mode features of various tvpes of prosthetic cardiac valves has been developed. The model consists of a saline-filled chamber in which a prosthetic valve is seated. The ball or disc of the valve can be activated by flow of the saline solution across the valve. The valve function is recorded using a commercial 3.5 mHz ultrasound transducer. The Beall, Smelloff-Cutter and Bjork-Shiley prosthetic valves have been studied with this technique. Each valve was monitored opening and closing at beam angles from 0 degrees to 90 degrees relative to the disc surface or the long axis of the ball excursion. The suture ring, disc or poppet and cage were easily identified and correlated with in vivo echocardiographic recordings. Beam angle was shown to be of critical importance, however, with optimal recordings made at or near 9 0 degrees. The disc or ball motion became difficult to assess at angles of less than 60 degrees.