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[Hemodynamic difference accounted for the orientation of a Björk-Shiley mitral prosthesis: a color Doppler
Y Jin-Nouchi1, Y Doi, H Odawara
1Department of Medicine and Geriatrics, Kochi Medical School, Nankoku.
Insights
Prosthesis orientation in mitral valve replacement did not significantly alter hemodynamics. However, orienting the major orifice towards the septum in Björk-Shiley prostheses was linked to reversed intracavitary blood flow.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Medical Imaging
Background:
- The Björk-Shiley tilting disc prosthesis is a common device for mitral valve replacement.
- Understanding the impact of prosthesis orientation on hemodynamics is crucial for optimizing patient outcomes.
Purpose of the Study:
- To investigate whether the orientation of the major orifice of a mitral tilting disc prosthesis influences intracavitary blood flow patterns and hemodynamics.
- To compare hemodynamic parameters between prostheses oriented towards the septum versus the posterior wall.
Main Methods:
- Color Doppler flow imaging was used to study intracavitary blood flow in 45 patients with well-functioning Björk-Shiley mitral prostheses.
- Patients were divided into two groups based on prosthesis orientation: towards the septum (Group S) or towards the posterior wall (Group P).
- Left ventricular and left atrial dimensions, peak mitral flow velocities, pressure gradients, and pressure half-times were measured.
Main Results:
- No significant differences were observed in left ventricular or left atrial dimensions between Group S and Group P.
- Hemodynamic parameters, including peak mitral flow velocities, pressure gradients, and pressure half-times, were similar in both groups.
- Mitral regurgitation was more frequent in Group S (35%) compared to Group P (9%), with hemodynamically significant regurgitation in 4 patients in Group S.
- Group S patients exhibited reversed intracavitary blood flow, with diastolic flow directed towards the left ventricular outflow tract.
Conclusions:
- The orientation of the major orifice of a mitral tilting disc prosthesis does not significantly affect major hemodynamic parameters.
- Septal orientation of the major orifice may be associated with altered intracavitary blood flow patterns and a higher incidence of mitral regurgitation.
Abstract:
To determine whether the orientation of the major orifice of a mitral tilting disc prosthesis affects hemodynamics, intracavitary blood flow patterns were studied in 45 patients with well-functioning Björk-Shiley mitral prosthesis using color Doppler flow imaging. The major orifice was oriented towards the septum in 23 patients (12 men, 11 women, age 58 +/- 11 years; group S), and towards the posterior wall in 22 patients (8 men, 14 women, age 55 +/- 9 years; group P). 1) The left ventricular end-diastolic dimensions (S: 4.8 +/- 0.9 cm, P: 5.2 +/- 1.0 cm), end-systolic dimensions (S: 3.6 +/- 0.9 cm, P: 3.8 +/- 1.2 cm), and left atrial dimensions (S: 5.0 +/- 1.0 cm, P: 4.7 +/- 0.9 cm) did not differ significantly between the 2 groups. 2) The peak mitral flow velocities (S: 1.43 +/- 0.38 m/sec, P: 1.43 +/- 0.27 m/sec), pressure gradients (S: 8.5 +/- 4.0 mmHg, P: 8.4 +/- 3.1 mmHg), and pressure half-times (S: 94.0 +/- 19.0 msec, P: 86.5 +/- 21.7 msec) did not differ significantly between the 2 groups. 3) Although mitral regurgitation was detected in 8 patients (35%) in the S group and in 2 patients (9%) in the P group, hemodynamically significant regurgitation was detected in only 4 patients in the S group (3 mild, one moderate). 4) The patients in the S group had reversed intracavitary blood flow; mitral flow was first directed towards the left ventricular outflow tract during diastole, while the outflow pattern was displaced into the left ventricular inflow tract.(ABSTRACT TRUNCATED AT 250 WORDS)