Abstract
BACKGROUND: Incomplete opening of unthrombosed Omnicarbon prosthetic heart valve has been reported these days. This study was designed to propose an estimation method based on the turbulent analysis in order to discriminate thrombosed cases from unthrombosed ones. METHODS: The test valve was mounted at the mitral position of a computer-controlled hydraulic mock circulator and driven under single-or doublepeaked flow condition. The valve tested as a thrombosed (malfunctional) model was mechanically restricted with the mobility of the occluder. On the other hand, the unthrombosed (normally functioning) valve model was driven under double-peaked flow. Continuous-wave ultrasound Doppler signal was measured in the vicinity of valve outlet during a whole diastolic period. The power spectrum of the signal was computed by a fast Fourier transform and the width of the spectrum (WoS (Hz)) was calculated as the value of standard deviation. Opening angle (OA) was also measured by a high speed CCD camera. RESULTS: The thrombosed model showed higher WoS value in average (422Hz) than the unthrombosed model (390Hz), while average incomplete OAs of the both models were the same (68.5deg). These in vitro results indicates that WoS value could be used for the discrimination.
