The Bleeding Time Response to Aspirin: Identifying the Hyperresponder

Abstract

The authors measured the template bleeding time in 11 normal people before and 2, 4, 12, 24, and 48 hours after the subjects ingested a single dose of 74 mg of aspirin (ASA). The entire experiment was repeated twice at two-week intervals, with the dose of ASA increased to 325 mg and finally 3,900 mg. The mean increase was maximal at 4 and 12 hours, regardless of the dose administered, with a return to baseline by 48 hours. The authors then performed bleeding times in a prospective randomized double-blinded fashion on an additional 39 subjects at baseline and seven hours after they ingested either placebo or ASA 325 mg. The mean baseline bleeding time was 5.2 minutes (SD +/- 1.4), with a mean prolongation after ASA of 2.1 minutes (SD +/- 1.9). The authors identified 5 of 37 (14%) subjects as hyper-responders (HRs) using the criterion of a bleeding time prolongation of greater than 5.9 minutes (greater than 2 SD beyond the mean prolongation). Neither baseline bleeding time, threshold sensitivity of collagen-induced platelet aggregation, nor other tests of hemostatic function discriminated HRs from normals. The authors conclude that in subjects with normal baseline bleeding times, a prolongation of greater than 5.9 minutes when measured seven hours after the administration of a single dose of 325 mg of ASA can discriminate HRs from normals.

Study for determination of the optimal cessation period of therapy with anti-platelet agents prior to invasive endoscopic procedures

“…Our results were consistent with previous studies reporting that ASA administration resulted in prolongation of the BT, and that it normalized 48 h after cessation. 13,15,38 In the present study, the BT was significantly prolonged until 5 days after cessation on the TP regimen, and the Tv was significantly increased after the administration of TP. Five days after TP cessation, however, there were no significant differences in BT or Tv from the respective levels before administration.…”

“…36,37 However, considering the risk of thromboembolism, there are reports that a shorter cessation period may be sufficient. 13,15 Some reports have evaluated hemostasis after the stopping of ASA; 12,14,38 however, there are few such reports on TP or combined therapy. 12,39 We studied the effect of ASA, TP, and a combination regimen on primary hemostasis in healthy volunteers.…”

The Management of Aspirin in Transurethral Prostatectomy: Current Practice in the UK

“…9 These are patients that have an exaggerated response to aspirin. 13,14 However, measuring the bleeding time in pre-operative patients is of little benefit. The test is operator-dependent and difficult to perform.…”

Hemorrhagic Cholecystitis in an Elderly Patient Taking Aspirin and Cilostazol

“…Platelet counts have not been found to be adversely affected [9]. Aspirin, on the other hand, has been shown clearly to prolong bleeding time and affect platelet aggregation [8, 10, 11]. …”