Effects of platelet inhibitors on the platelet aggregation induced by plasma from patients with thrombotic thrombocytopenic purpura

Abstract

Antiplatelet drugs have been used in the treatment of thrombotic thrombocytopenic purpura (TTP) but there in vivo efficacy remains controversial. It has been shown that, in vitro, the plasmas obtained from patients with TTP induced the aggregation of washed platelets from normal donors as well as patients in remission. The effects of platelet inhibitors on the TTP plasma-induced platelet aggregation were examined. It was found that aspirin, indomethacin, ibuprofen, sulfinpyrazone, 5, 8, 11, 14-eisacotetraynoic acid, prostaglandin E1, prostaglandin I2, dBcAMP, apyrase, creatine phosphate/creatine phosphokinase, antimycin, 2-deoxy-D-glucose, dipyridamole, clofibrate, dextran 40, dextran 70, dibucaine, xylocaine, methylmaleimide, and ethylenediamine tetraacetic acid had little or no effect at all. These data lead us to conclude that at least in certain cases, antiplatelet drugs probably play a limited role in the treatment of patients with TTP.

Nonsteroidal Anti-inflammatory Drug Induced Thrombotic Thrombocytopenic Purpura

“…Data from this study demonstrated that at least in certain cases, antiplatelet drugs probably play only a limited role in the treatment of patients with TTP. 19 In another trial, prostacyclin (PGI2) infusion, again with the same principle, failed to reverse platelet aggregation caused by TTP. 20 …”

Treatment of Thrombotic Thrombocytopenic Purpura

“…This patient was also treated with peritoneal dialysis because of a rising BUN (117 mg/dl) and creatinine (6.2 mg/di) at a time when the platelet count had already normalized. Recent studies [19] have shown that various antiplatelet agents, including the four previously mentioned, have no effect on the in vitro platelet aggregation induced by plasmas obtained from patients with TTP. It is difficult to correlate possible therapeutic effects in vivo with any demonstrable in vitro effects of these drugs.…”