Thrombotic complications constitute an important risk in transplant recipients, in whom a hypercoagulable state and hypofibrinolysis have been associated with immunosuppressive treatment, especially with
cyclosporine. In no case have clotting and fibrinolytic abnormalities been correlated with
steroid immunosuppression, even though
steroids were always administered. Previous studies found a relationship between
hypercorticism and hypofibrinolysis both in
Cushing's disease and after
renal transplantation. The aim of this investigation was to compare fibrinolytic potential using the venous occlusion test in two similar groups of heart transplant patients treated with or without
steroids. Euglobulin lysis time,
tissue-type plasminogen activator and
plasminogen activator inhibitor-1 (PAI-1) activities, and
antigens were determined before and after the venous occlusion test. A reduced fibrinolytic potential (significant prolongation of lysis time) due to a significant increase in
PAI-1 activity and
antigen levels was found in heart transplant patients treated with
steroids, as compared with patients without
steroid treatment and control subjects. The prevalence of reduced fibrinolytic potential was 69.2% (18 cases) in the
steroid-treated group and 34.8% (8 cases) in the non-
steroid-treated group. In every case, the impaired fibrinolytic potential was due to high basal
PAI-1 levels. Our results are compatible with the presence of a hypofibrinolytic state secondary to long-term
steroid treatment. In heart transplant recipients,
steroid-induced hypofibrinolysis may constitute a further risk factor for thrombotic disease.