الفهرس 
pROPHYLACTIC TREATMENT OF PROSTHETIC VALVE DYSFUNCTION
Prevention of Mechanical valve thrombosis:-Only 14 pages are availabe for public view
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Abstract
Forty five patients with prosthetic or bioprosthetic valve dysfunction were the subject of this
study. They presented to surgery in the period between July 1990 and June 1991 at Ain Shams
University hospital.
Patients included in this study were classified into 3 groups with 15 patients in each group
(prosthetic valve endocarditis, prosthetic valve thrombosis and primary tissue valve failure).
These groups represented the main causes of reoperation after prosthetic or bioprosthetic valve
replacement in our department.
The time elapsed between the primary operation and the onset of valve dysfunction varied according
to the type of valve dysfunction. It was 28 months for prosthetic valve endocarditis, 34 months
for prosthetic valve thrombosis and about 9 years for primary tissue valve failure.
While the dysfunction of mechanical valves presents a catastrophic problem, the primary tissue
valve failure is usually progressive process with significant bioprosthetic stenosis andjor
regurgitation may occur in a relatively asymptomatic patients.
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In addition to clinical features of the valve dysfunction on admission and laboratory findings
especially blood cultures for patients with suspected PVE and abnormal coagulation profile found
in majority of patients with suspected prosthetic valve thrombosis, our diagnosis for these cases
with suspected valve dysfunction was confirmed by complete echo cardiographic study.
Especially transesophageal echocardiography was found to be very helpful in diagnosis of such
cases. This improvement in diagnostic tests may facilitate optimal timing for surgical
intervention.
Twenty-six patients underwent elective reoperation. Nineteen patients underwent emergency surgery
due to rapid deterioration in their hemodynamics with low cardiac output and/or severe prosthetic
valve obstruction with frank pulmonary edema.
The overall operative mortality was 24.4% (ll/45) with the higher mortality rate reported in cases
of prosthetic valve endocarditis (33%) followed by prosthetic valve thrombosis (26.6%) and the
least mortality reported after reoperation due to primary tissue valve failure (13%).
Statistical analysis showed a significant better result
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tOr the patients undergoing elective reoperation with stable preoperative hemodynamic, patients
in preoperative NYHA class II or III and patients with good preoperative left
ventricular function.
The survivors (34 cases) were followed for a period of
12 months with only 2 cases of late mortality were recorded.
The preoperative functional class markedly improved in the majority of survivors (23 patients were
in NYHA class I) and 7 patients were in class II and only 4 patients were in class III.
A protocol for management of cases with prostheti valve dysfunction is proposed for application.