Introduction : Patients with implanted bioprostheses are at risk of structural dysfunction which results from the limited durability of biological valves. The aim of this study was to analyse the mechanism of bioprosthesis degeneration and to evaluate the usability of transthoracic and transoesophageal echocardiography in determining the indications for reoperation in 117 patients with a bioprosthesis implanted before 65 years old.
Material and methods : The study comprised 117 consecutive patients (M – 27, F – 90, age 48-74 years, 57.5 ±9.5 years) with a bioprosthesis implanted under the age of 65, who were examined in accordance with the accepted protocol and whose complete clinical and echocardiographic documentation was collected. The scheduled echocardiographic examination was performed annually from the 5 year after implantation of the bioprosthesis in patients with a valve implanted over the age of 35 years and from the 1 year after bioprosthesis implantation in patients with a prosthesis implanted at a younger age. Unscheduled echocardiographic examinations were performed only on clinical indications.
Results: During the period under observation, due to degeneration of the bioprosthesis 76 patients were reoperated, including 62 patients with mitral bioprostheses. In 88.7% of patients with degeneration of mitral valve bioprostheses, regurgitation was observed. In 69% of patients with aortic bioprostheses, valve dysfunction was the dominant mechanism of stenosis.
Conclusions : The most common mechanism of structural dysfunction of a mitral bioprosthesis is regurgitation caused by prolapse or perforation of one of the leaflets. Degeneration of an aortic bioprosthesis usually results in aortic stenosis. In cases of bioprosthesis degeneration connected with stenosis, transthoracic echocardiography was sufficient for the evaluation of valve dysfunction. In the case of bioprosthesis dysfunction accompanied by regurgitation, transoesophageal echocardiography was more informative to decide when the operation should be performed.