Thrombotic complications of BMT: association with protein C deficiency.

A decrease in levels of circulating anticoagulant protein C has been shown to occur following autologous BMT, and this deficiency may contribute to a hypercoagulable state placing patients at risk for thromboembolic events. We report four patients who suffered a variety of thrombotic complications following BMT (non-bacterial thrombotic endocarditis, superior vena cava thrombosis, thrombotic stroke, purpura fulminans, small bowel infarction secondary to diffuse microvascular thrombosis), which were preceded by or temporally related to decreased levels of protein C. Treatment with fresh frozen plasma (FFP) led to slight, temporary increases in protein C levels but infusions of FFP did not prevent either death or extension of the thrombus in these four cases, suggesting the need for higher protein C doses and/or concomitant anticoagulation. Though no direct causal relationship between these thrombotic complications and the protein C deficiency can be proved, a generalized hypercoagulable state caused by protein C deficiency may have contributed to the development, severity or progression of these complications.