Effects of Quyu Xiaoban Capsules on Clinical Outcomes and Platelet Activation and Aggregation in Patients with Unstable Angina Pectoris

Abstract

To investigate the effects of the Traditional Chinese Medicine (TCM) Quyu Xiaoban capsules (QYXB) on clinical outcomes and platelet activation and aggregation in patients with unstable angina pectoris (UAP) and phlegm and blood stasis syndrome. Ninety (90) UAP patients were randomly divided into two groups: the control group received a loading dose of 300 mg aspirin and a maintenance dose of 100 mg of aspirin plus baseline therapy for 4 weeks, and the trial group received the same doses of aspirin and baseline therapy plus QYXB for 4 weeks. The severity of anginal attacks, alterations of TCM symptoms and signs, and electrocardiographic (ECG) changes were observed in all patients before and after treatment. Plasma platelet aggregation (PAG) rate and P-selectin level were measured in all patients at baseline and at the end of the fourth week. After treatment for 4 weeks, both group of patients showed improvement in the severity of angina pectoris and TCM symptoms and signs, and there was a significant difference of the total effective rate in clinical improvement between the two groups, whereas no difference of the total effective rate in ECG improvement between the two groups was found. Compared with the baseline level, PAG rate in both groups decreased significantly at the end of the fourth week (63.74 +/- 11.18% versus 55.69 +/- 10.40 % in the control group, and 63.83 +/- 12.70% versus 50.04 +/- 8.91% in the trial group). Similar changes of P-selectin levels were observed in both groups (9.40 +/- 1.25 ng/mL versus 8.90 +/- 1.34 ng/mL in the control group and 9.56 +/- 1.16 ng/mL versus 7.80 +/- 0.98 ng/mL in the trial group). However, both PAG rate and P-selectin level decreased to a greater extent in the trial group than in the control group after treatment, and the difference between treatment was significant (both p<0.05). Nevertheless, these biochemical changes were too small to explain fully the beneficial clinical outcomes achieved by QYXB capsules. On the background of baseline and aspirin therapy, QYXB capsules significantly attenuated anginal attacks and improved TCM symptoms and signs in patients with UAP, and the exact mechanisms underlying these therapeutic effects remain to be explored.