Management of factor XI inhibitor for cardiac intervention: successful treatment with immunosuppressive therapy and plasma exchange.

Two cases with congenital homozygous factor XI deficiency developed a factor XI inhibitor following repeated plasma transfusions. Case 1 was given cyclophosphamide, intravenous immunoglobulin, and steroids. The factor XI inhibitor disappeared on day 103 and cardiac catheterization was performed without complications after giving fresh frozen plasma. Case 2 was effectively managed by plasma exchange for cardiac catheterization and surgery. However, after five plasma exchange procedures, the same plasma volume exchange was not effective in shortening the activated partial thromboplastin time (APTT). A significant heparin rebound occurred 4 h after heparin neutralization with protamine sulphate for which the patient needed to have a blood clot evacuated from around the heart.