Abstract: Objective To study the therapeutic effect of different doses of ticagrelor combined with low molecular weight heparin sodium in the patients aged≥80 years with unstable angina pectoris (UAP). Methods Eighty-six elderly patients aged≥80 years with UAP in our hospital from April 2020 to April 2021 were randomly divided into low-dose group and high-dose group, with forty-three cases in each group. The high-dose group was treated with high-dose ticagrelor (90 mg, twice per day) combined with low molecular weight heparin sodium, and the low-dose group was treated with low-dose ticagrelor (45 mg, twice per day) combined with low molecular weight heparin sodium. The clinical effects of the two groups after 4 weeks of treatment were compared. And the cardiac function indexes [left ventricular end-diastolic diameter (LVEDD), left ventricular ejection fraction (LVEF)], inflammatory factors [high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6) ] and endovascular function indexes [endothelin-1 (ET-1), nitric oxide (NO)] before and after 4 weeks of treatment were compared. The adverse cardiac events and bleeding events 6 months after treatment were recorded and compared between the two groups. Results There was no significant difference in the total effective rate between the high-dose group (95.35%) and the low-dose group(90.70%) (P>0.05). After 4 weeks of treatment, the level of LVEDD in the two groups was significantly lower, and the level of LVEF was significantly higher than that before treatment (P<0.05). After 4 weeks of treatment, the levels of hs-CRP, IL-6 and ET-1 in the two groups were significantly lower, and the level of NO was significantly higher than that before treatment(P<0.05), especially in the high-dose group (P<0.05). The incidence rate of adverse cardiac events in the high-dose group was 16.28%, compared with 2.33% in the low-dose group (P<0.05). The incidence rate of bleeding events in the high-dose group was 18.60%, compared with 4.65% in the low-dose group (P<0.05). Conclusions Different doses of ticagrelor combined with low molecular weight heparin sodium shows significant effects in the treatment of UAP. High-dose ticagrelor can inhibit the release of inflammatory factors and protect vascular endothelial function significantly, but low-dose ticagrelor is safer.

Key words: unstable angina pectoris, advanced age, ticagrelor, low molecular weight heparin sodium, efficacy, vascular endothelial function