[A new parameter for evaluating platelet aggregation in patients with chronic cerebral infarction].
We present a new sensitive parameter for evaluating ADP- and collagen-induced platelet aggregations. This parameter was used to re-evaluate platelet functions in chronic cerebral infarction. This parameter, the platelet aggregatory threshold index (PATI), was determined by the platelet aggregation curves obtained with four concentrations of two inducers (ADP; 0.5, 1.0, 2.0, 4.0 mumol/l and collagen; 0.125, 0.25, 0.5, 1.0 microgram/ml), and it indicated the concentration of the inducer that produced 50% of the aggregation rate at 5 min of ADP (4.0 mumol/l) or collagen (1.0 microgram/ml) induced aggregation curve. PATI was significantly correlated with the minimum concentration in ADP and collagen-induced aggregation, at which irreversible aggregation was induced. A negative correlation was shown between PATI and the rate of ADP (4.0 mumol/l)-induced maximum aggregation determined by the ordinary method, while no correlation was found between PATI and the rate of collagen (1.0 microgram/ml)-induced maximum aggregation. In normal elderly individuals, PATI obtained with ADP decreased significantly with age and showed no sex difference. Patients who had chronic cerebral infarction showed a significantly lower PATI with both inducers when compared to healthy elderly individuals, but the maximum aggregation rates obtained from the same platelet aggregation curves induced by ADP (4.0 mumol/l) or collagen (1.0 microgram/ml) showed no difference between the two groups. PATI reflects to be a more quantitative sensitivity of platelet than ordinary parameters such as the maximum aggregation rate. Determination of PATI may allow the detection of activated platelets in patients with chronic cerebral infarction.
Hokudan Clinic, Hyogo-pref.
M
M
Imiya
T
T
Matsuo
D000368:Aged; D000375:Aging / Q000097:blood; D002544:Cerebral Infarction / Q000097:blood*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D008722:Methods; D010974:Platelet Aggregation