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Primary tissue failure in pericardial heart valves.
The Journal of Thoracic and Cardiovascular Surgery
|September 1, 1987
Summary
Primary tissue failure in pericardial valves, including newer models, is linked to leaflet tears. Tissue ingrowth and endothelialization may reduce this failure rate by minimizing leaflet abrasion on the stent frame.
Area of Science:
- Biomaterials Science
- Cardiovascular Surgery
- Medical Device Engineering
Background:
- The Ionescu-Shiley pericardial valve has shown a significant incidence of primary tissue failure.
- Severe regurgitation due to leaflet tears near the cloth-covered stent edge is a common issue.
Purpose of the Study:
- To investigate the occurrence of primary tissue failure in newer pericardial valves (Ionescu-Shiley low-profile and Hancock).
- To elucidate the mechanisms behind tissue failure in these prosthetic heart valves.
Main Methods:
- In vitro accelerated fatigue studies on seven 29 mm pericardial valves.
- Clinical evaluation of early experience with Ionescu-Shiley low-profile and Hancock pericardial valves.
- Analysis of eight explanted valves to identify failure points and tissue ingrowth.
Main Results:
- In vitro studies revealed premature leaflet failure due to abrasion against the stent's cloth-covering.
- Clinical follow-up (up to 4 years) indicated tissue failure also occurs in newer pericardial valve designs.
- Explanted valves showed leaflet tears primarily at the top of stent posts with less tissue ingrowth, near suture lines.
Conclusions:
- Both in vitro and clinical findings suggest abrasion and stress concentration from sutures contribute to pericardial valve tissue failure.
- Endothelialization and host tissue ingrowth appear to mitigate leaflet abrasion and reduce tissue failure incidence.
- Further research is needed to optimize pericardial valve design and implantation techniques to prevent long-term tissue failure.