Hemodynamic performance of four mechanical bileaflet prosthetic valves in the mitral position: an echocardiographic study

Comprehensive hemodynamic assessment of 368 normal St. Jude Medical mechanical mitral valve prostheses based on early postimplantation echocardiographic studies

BACKGROUND

Two-dimensional and Doppler-derived echocardiographic data on normal St. Jude Medical mechanical mitral valve prosthesis function have been reported but remain limited.

METHODS

Comprehensive retrospective two-dimensional and Doppler echocardiographic assessment of 368 normal St. Jude Medical mechanical mitral valve prostheses was performed early after implantation. The early postimplantation hemodynamic profiles of 98 patients were compared with profiles obtained by follow-up transthoracic echocardiography performed <13 months after implantation.

RESULTS

Using mean ± 2 SDs to define the normal distribution of values for Doppler-derived hemodynamic variables, the calculated normal ranges of values were as follows: mean gradient, 2 to 7 mm Hg; peak early mitral diastolic velocity (E velocity), 1.1 to 2.4 m/sec; time-velocity integral of the mitral valve prosthesis (TVIMVP) 20 to 50 cm; ratio of the TVIMVP to the time-velocity integral of the left ventricular outflow tract (TVILVOT), 0.9 to 2.5; pressure half-time, 35 to 99 msec; and effective orifice area, 1.12 to 3.24 cm(2). Patients with severe prosthesis-patient mismatch (ie, indexed effective orifice area ≤ 0.9 cm(2)/m(2)) had significantly higher mean gradients, E velocity, TVIMVP, and TVIMVP/TVILVOT. There was a trend for longer pressure half-times for patients with severe prosthesis-patient mismatch than for patients without severe prosthesis-patient mismatch, but none of these patients had pressure half-times > 130 msec. Among the 98 patients with follow-up transthoracic echocardiography <1 year after implantation, no significant differences were observed between early postimplantation findings and follow-up hemodynamic profiles.

CONCLUSIONS

This study establishes parameters (mean ± 2 SDs) defining the distribution of values for Doppler-derived hemodynamic data with normal St. Jude Medical 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.

Doppler Echocardiography of 79 Normal CarboMedics Mitral Prostheses: A Comprehensive Assessment Including Time-Velocity Integral Ratio and Prosthesis Performance Index

Few reports have been published on the normal Doppler-derived echocardiographic data for CarboMedics (CarboMedics Inc., Austin, TX) prosthesis function in the mitral position. The purpose of this study was to provide a comprehensive Doppler echocardiographic assessment of normal CarboMedics mitral prosthesis function in a large number of patients. All of the important Doppler-derived hemodynamic variables reported to date were used. The pressure half-time was less than 130 msec in all patients, and nearly all patients (95%) had either a peak early mitral diastolic velocity of 2 m/s or less or a mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio of less than 2.2, regardless of prosthesis size or left ventricular function. No significant differences were found among different prosthesis sizes for effective orifice area, effective orifice area indexed to body surface area, or prosthesis performance index.

Doppler echocardiography of 119 normal-functioning St Jude Medical mitral valve prostheses: A comprehensive assessment including time-velocity integral ratio and prosthesis performance index*

The purpose of this study was to provide, in a large number of patients, comprehensive Doppler echocardiographic assessment of normal St Jude Medical mitral valve prosthesis function using Doppler-derived hemodynamic variables, including the mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio and prosthesis performance index. The pressure half-time was less than 130 milliseconds in all patients, and all but one patient had either a peak early mitral diastolic velocity of 2 m/s or less or a mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio of less than 2.2. There was a significant (P < .001) negative correlation between the prosthesis performance index and prosthesis size. This negative correlation suggests that there is more efficient use of the in vitro geometric orifice area with smaller prostheses.

Experience of the small size (25 mm) Sorin Bicarbon bileaflet prosthetic valve in patients with small mitral annuli

BACKGROUND

Currently, there is a tendency to use large-size prosthetic valves in mitral position in order to achieve better hemodynamic performance. We aimed to evaluate hemodynamic performance of 25 mm prosthetic valves in mitral position.

METHODS

Between August 1998 and May 2000, a total of 40 patients, 34 women and 6 men (mean age 42 +/- 12 years), underwent mitral valve replacement with 25 mm bileaflet mechanical valve. Preoperative functional capacity was New York Heart Association classes III and IV in 31 patients. Major indication for surgery was severe mitral stenosis in all patients.

RESULTS

Total hospital mortality was 5% (two patients). Mean follow-up period was 14.7 +/- 4.9 months (2 to 23 months). No thromboembolic event, paravalvular leak, mechanical failure, endocarditis were observed during the follow-up period. Postoperatively 92.5% of the patients were in the functional capacity of New York Heart Association class I. Postoperative echocardiographic observations have given an average pulmonary artery pressure of 29 +/- 2 mmHg, effective orifice area as 2.95 +/- 0.1 cm2, and mean prosthetic gradient as 6.5 +/- 2.7 mmHg.

CONCLUSION

In short- and mid-term, small-size (25 mm) Sorin mechanical mitral valves had excellent hemodynamic performance in patients with severe mitral stenosis, moderate or serious pulmonary hypertension, and small mitral annuli, whose body surface area was smaller than 1.6 m2.