[Long-term outcome of bioprostheses]

The major advantage of cardiac bioprostheses, apart from the good haemodynamic performance of recent models, is that they are not thrombogenic, so that the patient does not have to follow a life-long anticoagulant treatment. However, their major disadvantage, in comparison with the mechanical prostheses, is that they deteriorate over time. This study defines the durability of bioprostheses over the first seven years and beyond seven years. During the first seven years, if we compare the risk of thromboembolic and haemorrhagic complications of anticoagulant treatment to the risks of tissue deterioration, there is a clear advantage in favour of the bioprostheses. However, this is only true in adults, as in patients under the age of 20, the bioprostheses deteriorate much more rapidly. Few statistics are available concerning the followup of bioprostheses beyond seven years. However, on the basis of these statistics, absence of deterioration was observed in 75% of cases at 9 years and in 65% of cases at 10 years. These figures demonstrate that the great majority, if not all, cases of bioprostheses implanted at the present time will not need to be changed before 8 to 15 years. These results justify the research currently underway in various centres to determine the cause of these deteriorations and to try to prevent them.