You have gone through a difficult period. Thromboembolism is known problem IN PATIENTS WITH PROSTHETIC VALVES. You are lucky to have recovered despite the complications. You have to be meticulous with Acitrom. The recommended INR in your case should be 3 to 3.5 (2.5 IS LOW) and may be Clopidogrel should be added. I do hope that your echo study shows normalisation of the valve function. It is very necessary to be under close observation of your treating cardiologist. The medications and level of INR I have suggested should be endorsed by your treating doctor. The LVEF should not bother you, it is reasonable.