Persistence of antibodies to the topical hemostat bovine thrombin

Immunoassays that detect antibovine thrombin product antibodies are not widely available. However, knowing whether these antibodies are present preoperatively would be useful because re-exposure to bovine thrombin-containing products is contraindicated in patients with pre-existing antiproduct antibodies due to the risk of developing immune-mediated coagulopathies. In these exploratory analyses, we characterized one aspect of immune sensitization, the persistence of circulating antibodies after exposure to bovine thrombin product.

Elapsed time since a historical surgical procedure with documented or highly likely use of bovine thrombin product was determined for 204 patients enrolled in a recently completed trial. After study completion, baseline samples were assayed for antibovine thrombin product antibodies using validated immunoassays. Antibody data were sorted by time elapsed since the historical procedure. The proportion of patients with antibovine thrombin product antibodies and 95% confidence interval (CI) were determined for each 1-year period, providing an estimate for antibody persistence.

Antibovine thrombin product antibodies were detected in 20.7% of patients (23 of 111; 95% CI 14.2%, 29.2%) with ≤1 year since the historical surgical procedure; 6.8% of patients (3 of 44; 95% CI 1.68%, 18.9%) with 1 to <2 years; 16.1% of patients (5 of 31; 95% CI 6.62%, 33.1%) with 2 to <3 years; and 5.6% of patients (1 of 18; 95% CI 0.00%, 27.6%) with ≥3 years since the historical procedure.

The proportion of patients with antibovine thrombin product antibodies ranged from 5.6% to 20.7% across the multiyear postoperative window. Clinicians should be aware that antibodies to bovine thrombin products may persist for years after exposure.