Evaluation of normal hemodynamic profile of CarboMedics prosthetic valves by Doppler echocardiography.

The authors investigated 163 CarboMedics bileaflet prosthetic valves--81 mitral prostheses (MP), and 82 aortic prostheses (AP)--to determine acceptable pressure gradients across normally functioning prostheses and effective mitral valve orifice (MVO) area by Doppler echocardiography. In MP, the mean gradient was 3.6+/-1.7 mm Hg, peak transmitral gradient was 8.7+/-3.7 mm Hg, and mean effective valve area was 2.3+/-0.7 cm2. There was a significant overlap in mean and peak transaortic gradients even with valves of the same size. In AP, the mean gradient was 14.7+/-5.1 mm Hg and peak pressure gradient was 26.1+/-8.2 mm Hg. They observed a weak inverse correlation between valve size and gradients in AP. Mean and peak pressure gradients tended to be higher with smaller valve sizes, but differences were statistically significant (P < 0.5) only when they compared the smallest vs the largest valves. Trivial to mild regurgitation was detected in 28.4% of MP and 54.8% of AP. From the data they conclude that CarboMedics valves offer relatively little resistance to forward flow, both in the mitral and aortic positions, and their hemodynamic profile is comparable to that of the St. Jude bileaflet valves described in published literature.