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Late results of valve replacement with the Björk-Shiley valve (1973 to 1982)
T A Orszulak1, H V Schaff, J M DeSmet
1Section of Thoracic, Cardiovascular, Vascular, and General Surgery, Mayo Clinic, Rochester, MN 55905.
Insights
This study evaluated the Björk-Shiley cardiac valve prosthesis in 1253 patients. Results show similar performance to other mechanical valves, with no evidence supporting elective removal of this prosthesis.
Area of Science:
- Cardiovascular Surgery
- Biomaterials Science
- Clinical Outcomes Research
Background:
- The Björk-Shiley prosthesis is a mechanical heart valve used in cardiac valve replacement surgery.
- Understanding the long-term performance and complication rates of this prosthesis is crucial for patient management.
Purpose of the Study:
- To assess the long-term outcomes of cardiac valve replacement using the Björk-Shiley prosthesis.
- To evaluate the impact of valve position and disc design on patient outcomes.
- To determine the incidence of valve failure, thrombosis, and thromboembolic events.
Main Methods:
- Retrospective analysis of 1253 patients who underwent cardiac valve replacement with the Björk-Shiley prosthesis between 1973 and 1982.
- Stratification of outcomes based on valve position (aortic, mitral, double valve replacement) and prosthesis model (spherical vs. convexo-concave discs).
- Follow-up for up to 10 years to assess survival, thromboembolism, thrombosis, and other complications.
Main Results:
- No strut fractures were observed in high-risk patients followed for 10 years.
- Late thrombosis occurred in 0.28 per 100 patient-years, with no significant difference between disc designs.
- Thromboembolic rates varied by valve position (2.1-4.6 per 100 patient-years), with no significant difference between disc designs.
- Ten-year survival estimates ranged from 55% to 65% depending on valve position.
- Overall event-free survival was similar across patient groups.
Conclusions:
- The Björk-Shiley prosthesis demonstrates performance comparable to other mechanical valves in long-term follow-up.
- Modifications in disc design did not significantly alter the risks of late valve thrombosis or thromboembolism.
- Current evidence does not support the elective explantation of the Björk-Shiley prosthesis.
Abstract:
Cardiac valve replacement with use of only the Björk-Shiley prosthesis was performed in 1253 patients between January 1973 and December 1982. There were 828 patients having aortic valve replacement, 280 patients having mitral valve replacement, and 145 patients having double valve replacement with aortic and mitral valve prostheses. Patient outcome was stratified according to multiple variables, including valve position and valve model (spherical versus convexo-concave discs). No valve failure due to strut fracture was identified in 26 high-risk patients (mitral valve replacement with greater than or equal to 29 mm implanted in patients less than or equal to 50 years of age) followed up for a mean of 10 years postoperatively. Fifteen patients had late thrombosis of their Björk-Shiley prosthesis (0.28 per 100 patient-years), but there was no significant difference in risk of valve thrombosis comparing the spherical and convexo-concave discs (0.27 per 100 patient-years versus 0.27 per 100 patient-years). One hundred two patients had 128 thromboembolic episodes; rates of thromboembolism after aortic valve replacement, mitral valve replacement, and double valve replacement were 2.1, 4.3, and 4.6 per 100 patient-years, respectively. Percentages of patients free from thromboemboli after aortic valve replacement, mitral valve replacement, and double valve replacement were 93% +/- 1%, 86% +/- 2%, and 89% +/- 3% at 5 years postoperatively and 87% +/- 2%, 79% +/- 5%, and 77% +/- 8% 10 years postoperatively. There was no significant difference in the rates of thromboemboli for spherical and convexo-concave discs for all patients and for each of the subgroups. Ten-year actuarial survival estimates for patients dismissed alive from the hospital after aortic valve replacement, mitral valve replacement, and double valve replacement with the Björk-Shiley valve were 65% +/- 4%, 63% +/- 5%, and 55% +/- 8%, respectively. Overall event-free survival (freedom from death, thromboembolism, anticoagulant-related bleeding, endocarditis, and reoperation) was similar for the three patient groups. Performance of the Björk-Shiley valve as judged by late patient follow-up is similar to other mechanical valves, and modifications in disc design do not appear to have reduced the threat of late valve thrombosis and thromboemboli. Evidence does not support elective explantation of this prosthesis.