Objective To observe the clinical effects of Guanxin Danshen Dripping Pills（冠心丹参滴丸） in the treatment of elderly patients with unstable angina pectoris of qi deficiency and blood stasis

and to explore the possible mechanism. Methods Totally 240 elderly patients with unstable angina pectoris of qi deficiency and blood stasis were randomly divided into a treatment group and a control group

with 120 cases in each group. On the basis of comprehensive and symptomatic treatment of western medicine

the treatment group was given Guanxin Danshen Dripping Pills

0.4 g each time

3 times a day

and the control group was given an oral placebo at the same dose for 4 weeks. After treatment

the efficacy of angina pectoris symptoms and electrocardiogram were observed in both groups. Seattle angina questionnaire（SAQ） score and global registry of acute coronary event（GRACE） risk score were measured before and after treatment. Peripheral blood platelet particles（PMPs） and level of surface membrane proteins CD40 L

CD62 p

CD63

PAC-1

serum metalloproteinase 9（MMP-9）

soluble intercellular adhesion molecule 1（sICAM-1）

type 1 tissue plasminogen activator inhibitor（tPAI-1） level

and adverse reactions were observed. Results Two cases in the treatment group and 4 cases in the control group fell out

118 cases and 116 cases finished in the treatment group and the control group

respectively. The effective rate of angina pectoris symptom and electrocardiogram in the treatment group were 94.07% and 87.29%

which were significantly higher than those of the control group of 82.76% and 76.72%（P<0.05）. After treatment

SAQ scores increased

GRACE scores decreased

and peripheral blood PMPs

CD40 L

CD62 p

CD63

PAC-1 and serum MMP-9

sICAM-1

tPAI-1 levels also decreased in both groups（P<0.05）

and the improvement of all indexes in the treatment group was better than that in the control group（P<0.05）. Conclusion Guanxin Danshen Dripping Pills may improve the efficacy in treating elderly unstable angina pectoris patients with qi deficiency and blood stasis syndrome. The mechanism may be related to the inhibition of platelet activation and the reduction of serum MMP-9

sICAM-1 and tPAI-1 levels.