Color doppler flow mapping of prosthetic heart valves

Seventy Doppler velocity/flow studies of 23 different types of clinical and preclinical valves were performed after implantation in the mitral position in an animal model system. Sixty-four studies were performed early (0-10) days after implantation and 6 were performed 20 weeks after implantation. Color Doppler velocity/flow profiles were imaged in real-time and with electrocardiographic gating (Aloka system 880). The study protocol included imaging at 10 ms intervals throughout ventricular diastole and systole. Two carrier frequencies (2.5 and 5 MHz) and 3 pulsed repetition frequencies (4, 6 and 8 kHz) were used for a total of 5 maximal resolvable velocities without aliasing from 31 to 121 cm/s overall range of 4 to 121 cm/s). Velocities which aliased in the pulsed modes were quantified utilizing continuous wave Doppler with an independent transducer (Pedoff) or a dual function transducer. Three orthogonal planes were used. Studies were performed at 3 heart rates ranging from 60 - 120/min and at cardiac outputs ranging from 2 - 3.5 1/min, which were within the normal ranges for these animals