The Aspirin Bleeding Time - A Screening Test for Evaluation of von Willebrand’s Disease

In an attempt to elucidate the usefulness of the Bleeding Time (BT) post Aspirin (ASA) ingestion this test was done with other tests of coagulation in 30 controls and 77 patients evaluated for a possible bleeding diathesis. Coagulation studies included PT, PTT, TT, VIII AHF & AGN, IX, XI, XIII platelet retention and aggregation, and modified Ivy BTs pre and 2 hrs. post 600 mgms ASA. The mean control BT in 25 normals was 3.6'±3.2' (3SD). Following ASA the BT was 6.4'±4.1' (3SD). 5/30 “controls” without bleeding histories had abnormal BTs post ASA. In this group, 4 were proven to have unrecognized von Willebrand’s disease (VWD) and one a platelet defect. Of the 74 patients studied, 28 had initial BTs that were abnormal (23 with VWD and 5 with platelet defects). Of the remaining 46 with initially normal BTs, 26 had abnormal BTs post ASA. 13/26 had VWD at their first evaluation. In 9/26, however, the abnormal BT post ASA was the only abnormality at initial evaluation. On repeated testing, these patients were also shown to have VWD. 4/26 with abnormal BTs post ASA were found to have platelet abnormalities. The remaining 20 patients had normal BTs pre and post ASA. 16/20 revealed no hemostatic abnormality. In 4 eventually proven to have VWD, the BT post ASA was normal. The use of the BT post ASA raised the sensitivity of the BT as a screening test from 48% to 93% in the abnormal patient population. VWD appears to be the most common symptomatic/ asymptomatic bleeding disorder. The BT post ASA is a valuable screen in the evaluation of hemostatic defects i.e., mainly VWD, as also the occasional patient with a thrombocytopathy.