We analyzed serum from patients enrolled in the placebo/
unfractionated heparin arm of the GUSTO IV-ACS trial who had high likelihood of prior
heparin exposure. We selected 109 patients without
thrombocytopenia with the 30-day primary end point (death,
myocardial infarction [MI], or revascularization) and 109 age-, gender-, and race-matched controls who did not achieve the primary end point. An ELISA for anti-
platelet factor 4/
heparin antibodies was performed using 48-hour serum samples. The analyses were done by blinded investigators, and the results were correlated with clinical outcomes. Twenty-three of 218 patients (10.6%) had anti-PF4/
heparin antibodies. Patients with anti-PF4/
heparin antibodies were more likely to have death or MI (30.4% versus 11.3%, P=0.011) or MI (21.7% versus 6.2%, P=0.008) than patients who were negative for the antibody. After multiple logistic regression analysis, anti-PF4/
heparin antibodies remained a predictor of 30-day death or MI (odds ratio, 4.0; 95% CI, 1.4 to 11.3; P=0.0093) and MI (odds ratio, 4.6; 95% CI, 1.4 to 15.0; P=0.0108). The antibody was not associated with the composite end point (death, MI, or revascularization) or with death or revascularization alone.
CONCLUSIONS: