The effect of Sang-qi Granules on blood pressure and endothelial dysfunction in stageI or II hypertension: study protocol for a randomized double-blind double-simulation controlled trial

Abstract Background Hypertension is an important worldwide public health challenge because of its high prevalence and concomitant risks of cardiovascular disease. It induces half of the coronary heart disease and approximately two-thirds of the cerebrovascular disease burdens. Vascular endothelial dysfunction plays important roles in the pathophysiology of essential hypertension. Sang-qi Granules (SQG), a Chinese herbal formula, is used to treat I or II hypertension. Several animal experimental studies have shown that SQG can lower blood pressure and myocardial fibrosis by suppressing inflammatory responses. However, there is no standard clinical trial to confirm this and whether SQG can improve endothelial cell function is unknown.Methods In this randomized, double-blind, double-simulation controlled trial, 300 patients with stage I or II hypertension will be recruited and randomly allocated in a 1:1:1 ratio to group A(treatment with SQG and placebo of Cozaar), group B (treatment with Cozaar and placebo of SQG), and group C (treatment with SQG and Cozaar). SQG (or its placebo) will be administrated twice a day at the doze of 10g each time, and 50mg Cozaar(or its placebo) will be administrated once in the morning. The primary endpoint is the drug efficiency of the each three groups. The secondary endpoints are the change of average systolic and diastolic blood pressure during the day and the night, the change of blood pressure drop rate at night, target organ damage assessment (heart rate variability, ankle-brachial index and pulse wave velocity), symptoms improvement assessment (hypertension symptom scale, TCM syndrome integral scale, Pittsburgh sleep quality index scale, Self-Rating Anxiety Scale, Self-Rating Depression Scale and the Short Form-36 Health Survey), blood lipids, serum indicators of vascular function (changes in serum ET-1, TXA2, NO, PGI2 values) and safety indicators.Discussion This study will provide clinical evidence for the efficacy and safety of SQG in the treatment of hypertension. Meanwhile, the possible mechanism of SQG for lowering blood pressure will be further explored by observing the protective effect of SQG on vascular endothelial function, as well as its effect on related clinical symptoms, risk factors and target organs of hypertension.