| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1986: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1985: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research 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<0.01). We defined the upper limit for a normal PAI (%) value to be +13.9,
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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<0.01 versus baseline) and 21.4 <-!+> 21.3 (not significant from baseline), respectively. The regions with negative scintigraphic findings (PAI<13.9%), accumulated few, if any, labeled platelets and antithrombotic therapy had no significant influence on PAI (baseline 1.9 <-!+> 5.0; aspirin 1.0 <-!+> 8.3; ticlopidine 0.1 <-!+> 7.6). Our results suggest that a moderate dose of aspirin (325 mg bid) inhibits platelet deposition on carotid atheromatous lesions in vivo in patients with recent cerebral ischemia while the ticlopidine therapy (100 mg tid) was less conclusive than that of aspirin. The procedures described in this study may be useful for evaluation of antithrombotic drugs on platelet deposition at carotid atherosclerotic lesions. Less
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