title: Effect of aspirin and ticlopidine on platelet deposition in carotid atherosclerosis: assessment by indium-111 platelet scintigraphy.
abstract: The antiplatelet effects of aspirin and ticlopidine were studied by a dual-tracer method, using indium-111 labeled platelets and technetium-99m human serum albumin, in a group of 12 patients with suspected ischemic cerebrovascular disease. The magnitude of platelet accumulation at the carotid bifurcation was expressed as the ratio of radioactivity of indium-111 platelets deposited on the vascular wall to those circulating in the blood-pool (PAI, platelet accumulation index), 48 hr after injection of labeled platelets. PAI values were measured before (baseline studies) and after the antithrombotic therapies (aspirin studies: 325 mg bid for 22.3 +/- 1.3 days, ticlopidine studies: 100 mg tid for 21.8 +/- 2.1 days). At the baseline, the mean PAI value at 24 carotid bifurcations in the patient group was 15.7 +/- 15.3% (mean +/- S.D.) compared to -4.3 +/- 9.1 at 24 carotid bifurcations in 12 normal subjects (p less than 0.01). We defined the upper limit for a normal PAI (%) value to be +13.9, namely the mean PAI plus 2 SD for the carotid bifurcation in normal subjects and used this value for semiquantitative analysis. At the baseline, significant elevation of PAI (more than 13.9%; positive scintigram) was observed at 12 of 24 vessels, while 12 other regions were negative (less than 13.9%). In the lesions with positive scintigraphic results at the baseline, the mean PAI (%) value from the baseline, aspirin and ticlopidine studies was 29.5 +/- 7.0, 11.2 +/- 8.5 (p less than 0.01 versus baseline) and 21.4 +/- 21.3 (not significant from baseline), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000328:Adult; D000368:Aged; D001241:Aspirin / Q000627:therapeutic use*; D001792:Blood Platelets / Q000187:drug effects; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007204:Indium; D002537:Intracranial Arteriosclerosis / Q000000981:diagnostic imaging / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D011868:Radioisotopes; D011877:Radionuclide Imaging; D013668:Technetium Tc 99m Aggregated Albumin; D013988:Ticlopidine / Q000627:therapeutic use*
chemical_list: D011868:Radioisotopes; D013668:Technetium Tc 99m Aggregated Albumin; D007204:Indium; D013988:Ticlopidine; D001241:Aspirin