[Dysfunctions of heart valve prostheses and their surgical treatment]

Today the dysfunctions and complications relating to prosthetic cardiac valves are less frequent than 15-20 years ago. The materials used to manufacture mechanical cardiac valves, e.g. carbon pyrolyte, are much more resistant than Teflon or Derlin, and wear is therefore an exceptional event. In regard to bioprostheses, research is now aimed at preventing calcifications, tears and deterioration. Complications such as thrombosis and thromboembolic accidents are seen with all prosthetic cardiac valves and affect mechanical valves rather than bioprostheses. Hemorrhage, a complication of anticoagulant therapy, can be seen in any patient with a prosthetic cardiac valve undergoing such treatment. This complication is far less frequent in patients with a bioprosthesis since most of these (75%) are not on long-term anticoagulation. Paravalvular leakage is another rare complication related to valvular surgery and is often associated with prosthetic valve endocarditis. Prosthetic cardiac valve endocarditis is a very severe complication with a high mortality rate, and is more lethal when endocarditis occurs soon after surgery (up to 2 months). Elimination of infectious foci before surgery, observation of strict rules of asepsis, a high level of surgical technique, and prescribing of prophylactic antibiotic therapy during surgery, or later if necessary, will reduce the risk of prosthetic valve endocarditis. Where reoperation is decided for the above complications it is almost always necessary to replace the failing prosthetic valve.