Platelet aggregation in cerebrovascular diseases. Significance of platelet aggregability defined as the threshoid concentration of adenosine diphosphate(ADP) causing secondary aggregation

• Published in: Japanese Journal of National Medical Services Vol. 42; no. 1; pp. 21 - 27
• Main Authors: IINO Kozo, NAKATOMI Yasuo, NISHINO Yasushi, YOSHIDA Fujio, TAKENOYAMA Toshio
• Format: Journal Article
• Language: English; Japanese
• Published: Japanese Society of National Medical Services 1988; 一般社団法人 国立医療学会
• Subjects: ADP二次凝集閾値判定法; 抗血小板薬; 脳血管障害; 血小板凝集能
• ISSN: 0021-1699; 1884-8729
• DOI: 10.11261/iryo1946.42.21

Platelet agreggation was studied by the turbidimetric method using Lumi-aggregometer in 368 patients with cerebrovascular diseases and 124 adult controls. Platelet aggregability in response to adenosine diphosphate (ADP) was defined as the threshold concentration of ADP to cause secondary aggregation. The threshold concentration of ADP was greater than 4μM in 4 (8%), 1 or 2μM in 36 (74%), 1/2μM in 8 (16%), and 1/4μM in 1 (2%) of 49 adult healthy controls, whose ages ranged from 18 to 49 years. The degree of aggregability was defined as normal when the threshold concentration of ADP was 1 or 2μM, borderline when 1/2μM, increased when less than 1/4μM and decreased when greater than 4μM. The threshold ADP concentration was 4μM in 5 (7%), 1 or 2μM in 30 (40%), 1/2μM in 25 (33%), 1/8 or 1/4μM in 15 (20%) of 75 elderly control subjects, whose ages ranged from 50 to 91 years. This suggests that the ADP threshold concentration was increased in elderly controls.The increased platelet aggregation was seen in 30% of patients with TIA, 21% of patients with non-embolic cerebral infarction, 13% of patients with cerebral hemorrhage and 9% of patients with cerebral embolism. These results may indicate that patients with ischemic cerebrovascular disease have platelet hyperaggregability. In the patients with cerebral infarction, there were no relationships between platelet aggregability and the following factors: age, sex and the presence of hypertension or diabetes mellitus. Patients with increased platelet aggregation were slightly fewer in the first week after the onset than in other weeks. In addition, we showed that the platelet aggregability by the threshold concentrations of ADP in non-embolic cerebral infarction was useful for judgement of validity of antiplatelet drugs, such as ticlopidine. Lumi-aggregometerを用いて脳血管障害患者368例と対照者124例について血小板凝集能を測定し, 二次凝集をきたすADPの最低濃度で凝集能を判定した. 若年対照者(50才未満, 49例)ではADP 1～2μMで二次凝集をきたすものが全体の76%, 1/8μM 0%, 1/4μM 2%, 1/2μM 16%, 4μM以上8%であつた. 以上よりADP二次凝集閾値1～2μMを正常, 1/2μMを境界域, 1/4μM以下を凝集能亢進, 4μM以上を凝集能低下と判定した. 一方, 高令対照者(50才以上, 75例)では凝集能亢進群は20%であつた. 脳卒中病型別では凝集能亢進を示すものは脳血栓症21%, TIA 30%, 脳出血13%, 脳塞栓症9%と前二者で高率であつた. 脳血栓症では発症から1週間以降において凝集能亢進を示すものが多かつた. 性, 年令, 高血圧および糖尿病の有無と凝集能亢進との間には明らかな差異はなかつた. また, 4症例を呈示し, 二次凝集閾値判定法が抗血小板薬の効果判定にも役立つことを示した.