Fluoroscopic image of Starr-Edwards mitral prosthetic valve
(Sternal suture wires are seen in the background)
Fluoroscopic image of Starr-Edwards mitral prosthetic valve – end on view
Fluoroscopy is very useful in the evaluation of prosthetic valve function. In case of Starr-Edwards valve the prosthetic valve cage and the silastic ball inside are both visible on fluoroscopy. The movement of the ball inside the cage can be seen by live fluoroscopy and good movement usually indicates good prosthetic valve function (unobstructed prosthetic valve). Abnormal rocking sideways movement of the valve cage may indicate suture dehiscence and an unstable prosthesis. In an extreme case, such a prosthesis can get detached from the suture site with catastrophic results.
In case of tilting disc prosthetic valves (single leaflet or bileaflet), the tilting movement of the discs can be appreciated on fluoroscopy. If a leaflet is stuck due to thrombus formation within the structure of the prosthetic valve, it causes prosthetic valve dysfunction. Same is the case with poor movements of the disc. In some prosthetic valves, only the suture ring is radio opaque while the leaflets are not. In those cases, we can only detect abnormal movements of an unstable prosthesis. The disc movements cannot be seen by fluoroscopy and needs transthoracic or even transesophageal echocardiography for assessment.