title: Effects of dipyridamole and acetylsalicylic acid on platelet functions in patients with aortic ball-valve prostheses.
abstract: The effects of dipyridamole and ASA on platelet functions were studied in patients with aortic ball-valve prostheses.  Before ingestion, platelet adhesiveness was markedly reduced and platelet survival time slightly, but insignificantly shortened.  ASA prolonged the bleeding time, reduced collagen-induced platelet aggregation, and inhibited secondary aggregation initiated by adrenalin.  Similar effects were obtained with 2 Gm. of ASA alone as with 1 Gm. daily in combination with 225 mg. of dipyridamole.  Platelet adhesiveness remained low.  Depyridamole alone, 375 mg. daily, did not influence any of these parameters.  The mean platelet half-life was prolonged from 3.52 to 3.72 days by each drug and to 4 days by the combined treatment.  None of the differences was, however, statistically significant.  A clinical study with ASA has been started in a larger series of patients to evaluate the effect on arterial thromboembolism.
mesh_terms: D001021:Aortic Valve / Q000601:surgery*; D001241:Aspirin / Q000627:therapeutic use*; D001792:Blood Platelets / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D004176:Dipyridamole / Q000627:therapeutic use*; D006207:Half-Life; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D010973:Platelet Adhesiveness / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects; D013923:Thromboembolism / Q000517:prevention & control*
chemical_list: D004176:Dipyridamole; D001241:Aspirin