In vivo testing of an infection-resistant annuloplasty ring.
BACKGROUND
An infection-resistant surface incorporated into a prosthetic cardiac valve has great potential clinical applications.


METHODS
A sewing ring construct was created using ciprofloxacin-treated polyester. Then ciprofloxacin-treated and untreated constructs were implanted subcutaneously on the dorsum of rats and inoculated with Staphylococcus aureus. At 7, 14, and 30 days animals were sacrificed and the implants were retrieved. Each implant was assessed for frank purulence and gross tissue incorporation by a blinded observer. The implants were processed for conventional histology and examined by a blinded Pathologist. Ciprofloxacin-treated rings were also implanted in the absence of a bacterial challenge. At explantation, a maximal zone of inhibition, if present, was measured. Finally, ciprofloxacin was eluted with methanol from the explanted segments and the concentration of ciprofloxacin eluted was determined.


RESULTS
Ciprofloxacin-treated sewing rings had greater gross tissue incorporation than untreated rings in the presence of a bacterial challenge (P=0.005). Ciprofloxacin-treated rings also had a lower incidence of frank purulence, but this did not reach statistical significance. After 14 days of implantation, ciprofloxacin treated rings had fewer neutrophils (P=0.018) and greater histological tissue incorporation (P=0.017) than untreated rings. The explanted ciprofloxacin-treated rings maintained a zone of inhibition of 3.0+/-1.0 mm after 1 day of implantation and 1.3+/-0.6 mm after 2 days. Ciprofloxacin could be eluted in significant quantities from the explanted rings after 7 days of implantation.


CONCLUSIONS
Ciprofloxacin treated polyester can be incorporated into an annuloplasty ring construct that demonstrates excellent tissue incorporation and infection resistance. This study supports the use of this construct in the mitral position in a large animal model.
Monahan
Thomas S
TS
Department of Surgery, Division of Vascular Surgery, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, USA. tmonahan@bidmc.harvard.edu
Phaneuf
Matthew D
MD
Contreras
Mauricio A
MA
Andersen
Nicholas D
ND
Popescu-Vladimir
Alexandra
A
Bide
Martin J
MJ
Dempsey
Donald J
DJ
Mitchell
Richard N
RN
Hamdan
Allen D
AD
LoGerfo
Frank W
FW
D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology*; D004697:Endocarditis, Bacterial / Q000517:prevention & control; D006350:Heart Valve Prosthesis / Q000382:microbiology*; D008422:Materials Testing; D008943:Mitral Valve; D023421:Models, Animal; D016459:Prosthesis-Related Infections / Q000517:prevention & control*; D051381:Rats; D017208:Rats, Wistar; D013203:Staphylococcal Infections / Q000517:prevention & control*
D000890:Anti-Infective Agents; D002939:Ciprofloxacin