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Single-leg strut fractures in explanted Björk-Shiley valves
B A de Mol1, M Kallewaard, R B McLellan
1Safety Science Group, Delft University of Technology and Cardiopulmonary Surgical Center of Amsterdam, Netherlands.
Lancet (London, England)
|January 1, 1994
Summary
Fractures in Björk-Shiley convexo-concave valves are a significant concern. This study found a high rate of single-leg strut fractures, suggesting a need to revise current risk assessments and replacement guidelines.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Materials Science
Background:
- Björk-Shiley convexo-concave valves have been associated with fracture risks.
- Previous studies indicated a need for prophylactic valve replacement in specific patient groups.
Purpose of the Study:
- To investigate the incidence and characteristics of strut fractures in explanted Björk-Shiley convexo-concave valves.
- To evaluate the need for revising current risk calculations and replacement recommendations.
Main Methods:
- Retrospective analysis of 24 explanted Björk-Shiley convexo-concave valves from 22 patients.
- Examination of valves for structural defects, particularly single-leg strut fractures (SLF).
- Correlation of valve characteristics (e.g., degree, welding details) with fracture occurrence.
Main Results:
- Seven out of 24 valves (29%) exhibited single-leg strut fractures (SLF).
- Two additional valves showed signs suggestive of fatigue defects.
- Higher incidence of SLF observed in 70-degree valves, but also present in 60-degree valves.
Conclusions:
- A significant proportion of explanted valves showed fractures, indicating a persistent risk.
- Current hazard calculations and replacement guidelines may require revision.
- Manufacturing details, such as welding, might be crucial for estimating individual fracture risk.