Thrombosis of prosthetic heart valves: diagnosis and therapeutic considerations

rosthetic valve thrombosis (PVT) is a rare but serious complication of valve replacement, most often encountered with mechanical prostheses.The significant morbidity and mortality associated with this condition warrants rapid diagnostic evaluation.However, diagnosis can be challenging, mainly because of variable clinical presentations and the degree of valvular obstruction.Cinefluoroscopy (for mechanical valves) and transthoracic and transoesophageal echocardiography represent the main diagnostic procedures.Although surgical treatment is usually preferred in cases of obstructive PVT, optimal treatment remains controversial.The different therapeutic modalities available for PVT (heparin treatment, fibrinolysis, surgery) will be largely influenced by the presence of valvular obstruction, by valve location (left-or right-sided), and by clinical status.Hence, treatment of an obstructive left-sided PVT will differ from that of non-obstructive or right-sided PVT.The purpose of this article is to review the physiopathology, diagnosis and treatment of PVT and to provide recommendations for management. EPIDEMIOLOGY c Mechanical valve thrombosisThe incidence of obstructive PVT for mechanical valves varies between 0.3-1.3%patient years. 1 Thromboembolic complications, including systemic emboli, are more frequent and occur at a rate of 0.7-6% patient years.Non-obstructive PVT is a relatively frequent finding in the postoperative period, 2 with a reported incidence as high as 10% in recent transoesophageal echocardiography (TOE) studies.Although these are usually small non-obstructive thrombi, they underline the necessity of optimal anticoagulation in the postoperative period.According to a series of surgical interventions for PVT, the first postoperative year is marked by a 24% incidence of thrombosis, with a stable incidence between the second to fourth years of approximately 15%, with a subsequent decrease thereafter.3