Acute arterial embolism of lower extremity after mitral valve replacement in a chronic lymphocytic leukaemia patient: a case report

Abstract

Introduction Acute arterial embolism is a potential severe complication after cardiac surgery: it can be a clinical manifestation of early prosthetic valve (PV) thrombosis, whose incidence is higher in case of mechanical mitral valve or in presence of subtherapeutic anticoagulation, hemodynamic (atrial fibrillation) or haemostatic (obesity, anaemia, renal failure) predisposing factors (1). EACTA guidelines recommend to start anticoagulation during the first 24 hours after surgery, balancing the haemorragic risk(2). Although, in presence of specific comorbidities and risk factors, life-threatening thrombotic events can complicate postoperative period even following the international recommendations. Methods We report a 73-year-old man, suffering from chronic lymphocytic leukaemia (without treatment) and paroxysmal AF who received mitral mechanical valve replacement with a On-X 27/29 mm valve placed on anti-anatomic position because of a severe mitral insufficiency (with chordal systolic anterior movement) and single coronary artery by-pass graft. Unfractionated heparin (UFH) and acetylsalicylic acid were started 18 hours after surgery, in order to maintain an aPTT ratio of 1.5 to 2.5. On postoperative day (POD) 4 patient presented sudden pain and signs of acute hypoperfusion in left leg (distal femoral artery territory), requiring urgent surgery. Transthoracic echocardiography was performed but limited by artefacts and suboptimal acoustic windows. Considering the high risk surgery and the usefulness of early transoesophageal echocardiography (TOE), the patient received a general anaesthesia with tracheal intubation. Results Successful open embolectomy on the common femoral artery was performed; UFH perfusion was maintained during the whole duration of the procedure without haemorrhagic complication. Intraoperative TEO detected spontaneous echo contrast in left atrial appendage and reduced motion with impaired coaptation of the right leaflet (red arrows in figure); neither valvular-atrial-ventricular thrombus nor increased transvalvular gradient nor regurgitation were found. Postoperative TEO (POD 3) showed a PV with normal leaflets movement, without significative stenosis/regurgitation. Warfarin was started on POD 4 and heparin bridging was discontinued when INR target range was reached. Discussion In patient with multiple thrombotic risk factor (id malignancy, AF) adequate anticoagulation level can be difficult to reach: in these cases, serious thrombotic complications must be highly suspected even when guidelines have been followed. Prompt diagnosis and aggressive treatment are crucial to guarantee a good prognosis. Early TOE and a “tailored” anticoagulation therapy play a fundamental role in the management of such complications.