人工弁置換後の抗凝血療法 ―血小板凝集抑制剤の効果―

人工弁置換患者の血栓塞栓症（TE）は，長期予後の成績を左右する。　TEを減少させるために凝固因子を抑制するwarfarinと抗血小板剤による抗血栓療法が行われている。人工弁置換患者103例を対象に，抗血小板剤であるtrapidil（TP）とdipyridamole（DP）の血小板凝集能に与える効果を検討した。36ヵ月間検討したが，warfarin単独群は血小板凝集能に変化がなく，TP，DP共にADP凝集能を抑制した。しかし有意差の見られたのは全経過ではなく，凝集能抑制は強力かつ持続的ではなかった。またコラーゲン誘導凝集能は変化を認めなかった。TPとDPの抗血小板効果は同等と思われる。期間中の血栓塞栓発生は，warfarin単独群9.5％，TP群4.3％，DP群7.7％であった。臨床的に抗血小板剤の併用は有効と思われるが，血小板凝集抑制には投与量の増量，あるいは他の薬剤の検討が必要であろう。

To evaluate the effect of anti-thrombotic thrapy after valve replacement, serial platelet aggregation measurememnts were carried out in 103 patients. Patients were divided into three groups. e. i. warfarin alone (control), warfarin with trapidil (TP) of 300mg/day and dipyridamole (DP) of 300mg/day. The aggregation of platelet of the control group did not change through 36 months. TP group showed a decrease in platelet aggregation at 24 and 30 months from the pretreatment value. The aggregation of 24 month in TP was significantly lower than that of control. There was no difference of platelet aggregation between TP and DP group. The incidence of thromboembolism of control, TP and DP group were 9.5%, 4.3% and 7.7%, respectively. These data suggest that the supression of platelet aggregation .by TP and DP is not adequate to continue for long time and TP has similar anti-thrombotic effect to DP.