A novel St. Jude medical prosthetic valve with silver coated sewing cuff in sheep mitral valve replacement

Purpose: Prosthetic valve endocarditis is one of the life-threatening complications after valve replacement, which develops presumably secondary to bacterial invasion to the fabric sewing ring. The antibacterial activity of silver-containing compounds has recently been employed in constructing medical devices. In order to prevent prosthetic valve endocarditis, we evaluated, in vivo, the safety of a new St. Jude Medical prosthetic valve (SJV) with a silver coated sewing cuff in a sheep model. This study was aimed to quantify the release of silver, evaluate systemic or local tissue response to silver and identify any potential complications and adverse events. Methods: Thirteen sheep underwent mitral valve replacement (MVR) with SJV under cardiopulmonary bypass. Four SJV had half ring silver coated sewing cuff (Group I), six had whole ring coated (Group II) and three had non-coated (Group III). All sheep received the same perioperative antibiotic prophylaxis and no anticoagulant treatment. Animals were sacrificed 5 (Group I) or 10 (Group II & III) weeks after implant. Results: All sheep survived without evidence of thromboembolic events. Thrombus formation and vegetation were absent in all explanted hearts. Tissue ingrowth was seen properly on both coated and non-coated sewing cuffs. There was no difference in the parameters of granulomatous inflammatory infiltrate into the sewing cuff fibers of the coated and non-coated SJV (Table). Silver accumulation detected in the heart, lungs, liver, spleen and kidneys was much below toxic level. Blood silver concentration levels of animals with silver coated SJV peaked on postoperative days 3 and then decreased, however, levels were much less than toxic level. Conclusions: Silver coated SJV had appropriate local inflammatory tissue response and no systemic adverse effects in sheep undergoing MVR. Clinical Implications: This silver modification can potentially serve as prophylactic tool against prosthetic valve endocarditis. Group II Group III P Foreign body response (1-4 Scale) 2.50 2.67 NS Fibrous tissue integration (1-4 Scale) 2.75 2.17 NS Pannus thickness (mm) 0.312 0.572 NS.

Duke Scholars

Author He Xu Surgery, Surgical Sciences