title: Echocardiographic evaluation of porcine bioprosthetic valve degeneration.
mesh_terms: D000328:Adult; D001705:Bioprosthesis / Q000009:adverse effects*; D004452:Echocardiography; D006349:Heart Valve Diseases / Q000175:diagnosis; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged