Absence of Opening Click in Dehiscence of Mitral-Valve Prosthesis

Isolated absence of the opening click of the mitral disk-valve prosthesis was noted in six patients subsequently found to have suture disruption. Of five reoperated on, four survived. Angiocardiography was performed in two and demonstrated parabasilar leaks in both. This sign has hitherto been recognized only in thrombosis or swollen poppets of such prostheses. It is simple to detect and document by phonocardiography; it may be the only evidence of prosthetic valve dysfunction in a deteriorating patient since a murmur was heard in only two of six cases. It has not been found in any case in which the valve functioned normally. In suture disruption the valve is thought to "cock" abnormally because of inadequate support, so that blood flowing to the left ventricle partly flows through the dehiscence around the prosthesis and partly strikes the disk at an angle not exercising enough perpendicular force to open it abruptly and produce a click.