Introduction: Obstructive prosthetic valve thrombosis is a rare, but important complication due to the high levels of mortality and morbidity associated with it, be-ing more common in mechanical valves than in bio-prosthetic valves. The immediate postoperative period, discontinuation of anticoagulant therapy or pregnancy are the most frequently encountered risk factors in this pathology. The diagnosis is suggested by the cli-nical findings, confirmed by the data obtained from the echocardiographic and cinefluoroscopic examina-tions. The preferred treatment of recurrent obstructive mechanical valve thrombosis is the surgical interven-tion, but heparin therapy and fibrinolysis can also be a very good alternative.

Methods: Patient, 39 years, with mechanical prosthesis in mitral position for severe rheumatic mitral stenosis and tricuspid annuloplasty, with reimplantation of mi-tral mechanical prosthesis for obstructive thrombosis (thrombolysed), with atrial fibrillation, anticoagula-ted (subtherapeutic INR), hospitalized for dyspnea, fever, cough, mucopurulent expectoration. Clinical: diastolic murmur with increased intensity in the mi-tral area, absent opening click, low intensity of closing click.Paraclinical: hemocultures, uroculture – negative; microbiological examination of sputum positive for S. pneumoniae. Transesophageal echocardiography: ob-structive prosthetic valve thrombosis with dysfunction (blocked medial leaflet, lateral leaflet – low mobility), mean gradient increased, moderate paraprosthetic re-gurgitation, thrombus in the left ear, spontaneous con-trast in the left atrium.

Results: Anticoagulant therapy with unfractionated heparin and acenocoumarol was initiated, with mini-mal, initial clinical improvement, while the severity of echocardiographic parameters was maintained under therapeutic APTT and INR. Given the increased sur-gical risk, thrombolysis with tenecteplase was decided. In the echocardiographic re-evaluation, a significant improvement of the parameters was noted: mean gra-dient=8 mmHg, Vmax=1.8 m / s, EOA (PHT)=1.3 cm², with maintenance of prosthesis dysfunction (blocked medial leaflet–confirmed cinefluoroscopically), but with acceptable hemodynamics. Subsequently, the patient’s evolution was favorable. Considering the re-peated thrombosis episodes, it was decided to deter-mine the thrombophilia profile which showed high le-vels of lupus anticoagulant, protein S and C deficiency, (impossible to interpret in the context of oral anticoa-gulation), antithrombin III, factor V Leiden – normal values.

Conclusions: Although surgical treatment is conside-red to be an option for recurrent obstructive prosthetic thrombosis, fibrinolysis may be an effective alternative in the presence of an increased surgical risk (multiple heart surgeries in this case) or in the case of ineffective heparinotherapy. The case illustrates both the efficien-cy of fibrinolytic agents and the usefulness of transe-sophageal echocardiography in the diagnosis and in evaluating the effectiveness of the applied therapy. The patient has the indication of replacing the mechanical valve with a bioprosthetic valve, given the repeated epi-sodes of thrombosis.