title: Improved Pig Model to Evaluate Heart Valve Thrombosis.
abstract: Although the sheep is the most acceptable animal model for heart valve evaluation, it has severe limitations for detecting heart valve thrombosis during preclinical studies. While the pig offers an alternative model and is better for detecting prosthetic valve thrombogenicity, it is not often used because of inadvertent valve thrombosis or bleeding complications. The study aim was to develop an improved pig model which can be used reliably to evaluate mechanical heart valve thrombogenicity.
  
  
  
  Mechanical heart valves were implanted in the mitral position of indigenous pigs administered aspirin-clopidogrel, and compared with similar valves implanted in control pigs to which no antiplatelet therapy had been administered. The pigs were observed for six months to study their overall survivability, inadvertent bleeding/valve thrombosis and pannus formation. The efficacy of aspirinclopidogrel on platelet aggregation and blood coagulation was also recorded and compared between test and control animals.
  
  
  
  In comparison to controls, pigs receiving anti-platelet therapy showed an overall better survivability, an absence of inadvertent valve thrombosis/ bleeding, and less obstructive pannus formation. Previously unreported inhibitory effects of aspirin-clopidogrel on the intrinsic pathway of blood coagulation were also observed in the pig model. Notably, with aspirin-clopidogrel therapy inadvertent thrombus formation or bleeding can be prevented.
  
  
  
  The newly developed pig model can be successfully used to evaluate heart valve thrombosis following chronic orthotopic valve implantation. The model may also be utilized to evaluate other bloodcontacting implantable devices.
authors.affiliation: Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, India. Electronic correspondence: umashnkr@sctimst.ac.in.
authors.forename: Umashankar
authors.initials: U
authors.lastname: Payanam Ramachandra
authors.affiliation: Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, India.
authors.forename: Sachin J
authors.initials: SJ
authors.lastname: Shenoy
authors.affiliation: Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, India.
authors.forename: Sabareeswaran
authors.initials: S
authors.lastname: Arumugham
mesh_terms: D000818:Animals; D001241:Aspirin / Q000627:therapeutic use; D001777:Blood Coagulation / Q000187:drug effects; D001792:Blood Platelets / Q000187:drug effects; D000077144:Clopidogrel; D004195:Disease Models, Animal; D006349:Heart Valve Diseases / Q000517:prevention & control*; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects*; D006801:Humans; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D019106:Postoperative Hemorrhage / Q000517:prevention & control*; D013552:Swine; D013927:Thrombosis / Q000517:prevention & control*; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000627:therapeutic use
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin