THROMBOSIS OF MECHANICAL VALVES PROSTHESE S IN REUNION ISLAND

Between October 1991 and January 1995, 10 patients presented 14 episod es of thrombosis of mechanical valve prosthesis, 11 obstructive, 3 non obstructive. In two cases, the thrombosis was recurrent (one after thr ombolysis, one after surgical thrombectomy). In another two cases, the thrombosis was a recurrence (on a valve already surgically replaced b ecause of thrombosis). Anticoagulant therapy had been ineffective in 9 cases; protein S deficiency was diagnosed in one case. Transoesophage al echography allowed diagnoses in all cases. Thrombolysis was the tre atment of first intention in 9 cases (completed by a second course of thrombolysis in one case and by valvular replacement in two cases. The other patients were managed by immediate valve replacement in two cas es, thrombectomy in one case, long-term parenteral anticoagulation in two cases (one of which was followed by valve replacement). Transoesop hageal echography showed improved valve motion. Incomplete thrombus di ssolution was observed in 50% of cases. Thrombolytic therapy was compl icated by cerebrovascular accidents in two patients, one of which was fatal. One patient had regressive hemiplegia, one patient had a local hematoma. The authors conclude that thrombosis is a serious complicati on of valve replacement and usually occurs in patients inadequately an ticoagulated. Thrombolysis may enable some patients to avoid reoperati on but its risks limits its use to those patients thought to be unacce ptable surgical risks. An apparently high frequency of this complicati on durind this period has led to the initiation of a study to determin e the predisposing factors and to put preventive measures into action.