The Case of the Tainted Heparin

In January 2008, the Centers for Disease Control and Prevention (CDC) received several reports of facial edema, tachycardia, hypotension, urticaria, and nausea among patients undergoing hemodialysis at a pediatric hospital. In response, the CDC began a case-finding effort.

Investigators identified 152 reactions to unfractionated heparin in 113 patients from 13 states (including 130 reactions in 100 patients during hemodialysis and 8 reactions in 6 patients during cardiac procedures). In patients undergoing hemodialysis, the reactions occurred a mean of 5 minutes after exposure to heparin. Characteristics seen most often were hypotension (50%), nausea (49%), shortness of breath (38%), and facial swelling (24%). Urticaria, fever, chills, wheezing, and difficulty in swallowing were rare or absent. None of the 113 patients died.

Investigators conducted a facility-based case–control study and found that the reaction was associated most strongly with the use of heparin manufactured by Baxter Healthcare (administered in 92.8% of the cases), found in all case facilities and in only one control facility (100% vs. 4%; P<0.001). Lot information on Baxter heparin was available for 130 reactions; in 98.5% of cases, heparin contaminated with oversulfated chondroitin sulfate (OSCS) was found in the facility and could have been given to the patients. In in vitro testing, the OSCS-contaminated heparin led to a high level of kallikrein activation, which can lead to the release of bradykinin (a potent vasoactive mediator) and of C3a and C5a (potent anaphylatoxins).