Comprehensive hemodynamic assessment of 305 normal CarboMedics mitral valve prostheses based on early postimplantation echocardiographic studies

Background: Two-dimensional (2D) and Doppler-derived echocardiographic data on normal CarboMedics (CM) mechanical mitral valve prosthesis function have been reported but are limited.

Methods: Comprehensive retrospective 2D and Doppler echocardiographic assessment of 305 normal CM mechanical mitral valve prostheses (272 Standard and 33 Optiform) was performed early after implantation. The early postimplantation hemodynamic profiles of 80 patients were compared with profiles obtained by follow-up transthoracic echocardiography performed <1 year after implantation.

Results: CM Standard and Optiform prostheses had similar hemodynamic profiles. With mean ± 2 SDs used to define the normal distribution of values for hemodynamic variables, the calculated normal range of values was as follows: mean gradient, 2 to 7 mm Hg; peak early mitral diastolic velocity, 1.3 to 2.4 m/sec; time-velocity integral (TVI) of the mitral valve prosthesis (TVI(MVP)), 20 to 50 cm; ratio of TVI(MVP) to the TVI of the left ventricular outflow tract, 0.9 to 2.5; pressure half-time, 35 to 99 msec; and effective orifice area, 1.17 to 3.25 cm(2). Patients with severe prosthesis-patient mismatch (indexed effective orifice area ≤ 0.9 cm(2)/m(2)) had significantly higher mean gradients, peak early mitral diastolic velocities, TVI(MVP), ratios of TVI(MVP) to the TVI of the left ventricular outflow tract, and pressure half-time values than values without severe prosthesis-patient mismatch, but none had pressure half-time values > 120 msec. Among the 80 patients with follow-up transthoracic echocardiography within 1 year after implantation, no significant differences were noted between early postimplantation findings and follow-up hemodynamic profiles.

Conclusions: This study establishes parameters (mean ± 2 SD) defining the distribution of findings for Doppler-derived hemodynamic data with normal CM mechanical mitral valve prostheses. Prostheses with hemodynamic values outside these parameters are likely dysfunctional; however, prosthesis dysfunction may be present even when hemodynamic values are within these ranges.