Mid-Term Outcome of Mechanical Pulmonary Valve Prostheses: TheImportance of Anticoagulation

Introduction: Pulmonary valve replacement (PVR) is being performed more commonly lateafter the correction of tetralogy of Fallot. Most valves are replaced with an allograft or xenograft,although reoperations are a common theme. Mechanical prostheses have a less favorable reputationdue to the necessity of lifelong anticoagulation therapy and higher risk of thrombosis, but they arealso less likely to require reoperation. There is a paucity of data on the use of prosthetic valves inthe pulmonary position. We report the midterm outcomes of 38 cases of PVR with mechanicalprostheses.Methods: 122 patients who underwent PVR were studied. Thirty-eight patients, mean age 25 ±8.4 years underwent PVR with mechanical prostheses based on the right ventricular functionand the preferences of the patients and physicians. Median age of prosthesis was 1 year (range 3months to 5 years).Results: Seven (18%) patients had malfunctioning pulmonary prostheses and two patientsunderwent redo PVR. Mean International Normalized Ratio (INR) in these seven patientswas 2.1±0.8. Fibrinolytic therapy was tried and five of them responded to it well. There wasno significant association between the severity of right ventricular dysfunction, patient’s age,prostheses valve size and age of the prosthesis in the patients with prosthesis malfunction.Conclusion: PVR with mechanical prostheses can be performed with promising midtermoutcomes. Thrombosis on mechanical pulmonary valve prostheses remains a seriouscomplication, but most prosthesis malfunction respond to fibrinolytic therapy, underscoring theneed for adequate anticoagulation therapy.