194 THROMBOEMBOLIC ACUTE ST ELEVATION MYOCARDIAL INFARCTION AFTER TRANSCATHETER VALVE IMPLANTATION


 Transcatheter aortic valve implantation (TAVI) is an established treatment of severe symptomatic aortic valve stenosis and is an effective and less invasive treatment option compared with conventional surgical aortic valve replacement (SAVR) for patients considered inoperable or at high surgical risk. Thromboembolic and bleeding complications negatively impact recovery and survival after TAVI. This case describes one of the few reported TAVI-associated myocardial infarction due to thrombosis of the prosthetic aortic valve.
 A 82-years-old woman, suffering from severe symptomatic aortic stenosis, underwent TAVI. Before the procedure, coronary artery disease was excluded by invasive coronary angiography.
 Since the time of the discharge the patient didn't assume any therapy with aspirin or other antithrombotic drugs. A month after TAVI she complained persistent epigastric pain and was admitted to our department for anterior ST elevation myocardial infarction. Coronary angiography highlighted a monovascular coronary artery disease with thrombotic occlusion of the first diagonal and of the distal left anterior descending coronary artery. In consideration of the thrombotic load thyrofiban was started and it was performed a chest contrast CT which confirmed the diagnostic suspicion of bioprosthetic valve thrombosis. She was first treated with unfractionated heparin (UFH) and then oral anticoagulant therapy with warfarin was started. Echocardiograms (echo) showed a severely reduced systolic function (EF 25%) and high trans-prosthetic gradients (mean transprosthetic pressure gradient of 30 mmHg). On the 8th day after hospitalization she complained chest pain with evidence of moderate pericardial effusion. Epistenocardica pericarditis was therefore diagnosed and the patient started acetylsalicylic acid therapy with progressive clinical, instrumental and laboratory improvement. After 10 days of anticoagulation therapy, she underwent a transesophageal echocardiogram which turned out negative for bioprosthetic valve thrombosis. The predischarge transthoracic echocardiography showed severely reduced systolic function (EF 30%) with a mean transprothesic gradient of 12 mmHg; the circumferential pericardial effusion was mild-moderate but not haemodynamically significative. Therapy at discharged included warfarin and aspirin. Ten days after an echo showed a reduction of the pericardial effusion, an improved systolic function (EF 42%) and mean transprothesic gradient not changed significantly since discharge.
 Prosthetic valve thrombosis has been reported in up to 40% of patients after TAVI and this case hightlights the importance of antithrombotic therapy after this procedure. Therapeutic anticoagulation appears to be the only non-invasive treatment for resolving valve thrombosis but it is not clear how long this therapy should last for the prevention of prosthetic valve thrombosis.