الفهرس 
PROSTHETIC VALVE MALFUNCTIONOnly 14 pages are availabe for public view
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Abstract
Although, replacement of the mitral valve has become
relatively a simple procedure, it is not a procedure without
complications, as the surgery of mitral valve re-replacement is
still a continuing challenge to surgeons.(Matsuyama et al., 2003)
Reoperation on prosthetic heart valves is increasingly under
consideration for both clinical and prophylactic indications
(Piehler et al., 1995)
Therefore, therapeutic decision-making is very crucial in these
cases and hence requires an accurate assessment of the prognosis
of the disease.
Such prognosis is generally affected by a large number of
factors. The aim of this study was to identify these factors
associated with an increased operative risk in mitral valve rereplacement
for prosthetic mitral valve dysfunction.
The clinical picture of prosthetic valve dysfunction varied
according to the type of dysfunction present, such diagnosis can be
made by proper history, complete clinical examination and proper
investigation.
In our study, the diagnosis of prosthetic valve thrombosis, leak,
pannus or primary tissue valve failure in symptomatic patients was
sufficient indications for reoperation. In cases of prosthetic valve
endocarditis, medical treatment started first with antibiotic therapy
but this was always interrupted by surgical interference.
Patients with suspected prosthetic malfunction, transesophageal
echocardiography as well as color Doppler flow velocity mapping
gave valuable information more than the transthoracic approach.
Strong clinical suspicion of prosthetic valve dysfunction in
addition to the finding of echocardiographic study. Once diagnosis
was made by these diagnostic tests, other tests such, as cardiac
catheterization was not needed as to provide optimal timing to the
operation.
Early detection and management of prosthetic valve dysfunction
carries a better prognosis as once complications have manifested,
the patients prognosis depend upon how timely adequate
therapeutic management is administered which eventually means
reoperation without delay.(Dudeken et al., 1997)
Prosthetic valve thrombosis was the most frequent indication for
reopertaion in this study, as it remains high even with the newer
generations valves.
It was concluded that the surgical risk of prosthetic valve rereplacement
could be reduced dramatically with no significant
difference from that of the primary operation if the intervention is
not unduly delayed. The best time for reoperation should be before
hemodynamic deterioration and in the presence of preserved left
ventricular function.
In conclusion, the patient should be urgently diagnosed and
prepared without delay before complications start to occur such as
renal and hepatic failure, deterioration of NYHA class and the
development of pulmonary hypertention.
In our study, emergency re-repalcement significantly affected
our results in patients who underwent emergency reoperation due
to prosthetic valve dysfunction; the mortality was 57.1% in
contrast to 8% and 0% operative mortality for urgent and elective
reoperation respectively.
The left ventricular End-Diastolic Diameter (EDD), postoperative
ventricular tachycardia and\or ventricular fibrillation and
days ventilated by the patient have significant outcome of the
operative mortality