Post-cardiac surgery thrombotic thrombocytopenic purpura with digital ischaemia.

We report a case of thrombotic thrombocytopenic purpura in a woman post mitral valve repair who presented with unexplained thrombocytopenia, intermittent fever, acute renal failure and severe digital ischaemia. The diagnosis of thrombotic thrombocytopenic purpura was confirmed after exclusion of many of the aetiological factors of postoperative digital ischaemia, a positive haemolytic screen and blood film examination which showed schistocytes and fragmented red cells. Plasma ADAMTS-13 activity measured by enzyme-linked immunosorbent assay was reduced. Treatment of thrombotic thrombocytopenic purpura with exchange plasmapheresis and methylprednisolone was of paramount importance and the patient was discharged home on day 30 with complete recovery of haematological, neurological and renal function. In order to increase the awareness of this rare multisystem process, we report our experience in managing this life-threatening condition. Our discussion covers the diagnostic challenges, theories on aetiology, pathogenesis and treatment of this condition in the context of cardiac surgery.