Calcification and Oxidative Modifications Are Associated With Progressive Bioprosthetic Heart Valve Dysfunction

Area of Science:

• Biomaterials Science
• Cardiovascular Research
• Biochemistry

Background:

• Bioprosthetic heart valves (BHVs) are crucial for treating heart valve disease.
• BHV dysfunction necessitates reoperation over time.
• Understanding BHV degradation mechanisms is vital for improving valve longevity.

Purpose of the Study:

• To investigate the roles of calcium and oxidized amino acids in bioprosthetic heart valve dysfunction.
• To determine if these factors influence the time to reoperation.

Main Methods:

• Analysis of 47 explanted BHV aortic valve replacements.
• Quantification of calcium and oxidized amino acids (dityrosine, 3-chlorotyrosine) in BHV leaflets using atomic absorption spectroscopy and mass spectroscopy.
• Correlation analysis with clinical data, including comorbidities and time to reoperation.

Main Results:

• Explanted BHV leaflets showed significantly increased calcium and dityrosine levels compared to unimplanted valves.
• Dityrosine was site-specifically found in midleaflet regions.
• 3-Chlorotyrosine correlated with calcium in patients with coronary artery bypass grafting but not in others.
• Time to reoperation did not differ between calcified and non-calcified BHVs.

Conclusions:

• Both increased calcium and oxidized amino acids are associated with BHV dysfunction requiring reoperation.
• BHV calcium levels did not determine implant duration.
• Oxidized amino acid formation appears to play a critical role in bioprosthetic heart valve dysfunction.