Effects of sang-qi granules on blood pressure and endothelial dysfunction in stage I or II hypertension: study protocol for a randomized double-blind double-simulation controlled trial

Background Worldwide, hypertension is an important public health challenge because of its high prevalence and the concomitant risks of cardiovascular disease. It induces half of the coronary heart disease and approximately two-thirds of the cerebrovascular disease burden. Vascular endothelial dysfunction has important roles in the pathophysiology of essential hypertension. Types I and II hypertension can be treated with sang-qi granules (SQG), a Chinese herbal formula. Several experimental studies on animals have shown that SQG can lower blood pressure and myocardial fibrosis by suppressing inflammatory responses. However, no standard clinical trial has confirmed this. Whether SQG can improve endothelial cell function is unknown.