Effect of Different Antihypertensive Drugs on Central Blood Pressure

1. Study background Different antihypertensive agents induce varied response in terms of CBP, even if peripheral BP-lowering effects are similar. In ASCOT-CAFE study, the atenolol±thiazide group and the amlodipine±perindopril group had similar efficacy in lowering peripheral BP, but CBP was significantly higher in the atenolol±thiazide group. This, amongst other studies, provided grounds for BBs being exempted from first-line therapy for hypertension. A possible explanation for this suboptimal performace of BB in lowering CBP is that in the atenolol±thiazide group, the lowered heart rate and subsequently an increase in systolic time promotes the augmentation of systolic pressure waves by the pressure wave reflections. Second, the comparatively high vasoconstricting effects of atenolol±thiazide group may result in a more proximal formation of pressure waves. Recently, third-generation BBs such as nebivolol have been developed, with additional vasodilatory effects which distinguishes them from previous BBs, and less accentuated heart rate-slowing effects. However, the effect of these new-generation of BBs on CBP is yet to be elucidated. 2. Study objectives The primary objective of this study is to evaluate the clinical efficacy of nebivolol, a BB, in lowering the CBP compared to telmisartan, an ARB. 3. Medical devices and therapeutic agents The medical devices and therapeutic agents to be used in this study are the treatment modalities that have been proven to be beneficial in the treatment of hypertensive patients without clear contraindications. 4. Expected effects of the research The clinical benefits of lowering CBP as well as peripherally measured BP have been previously described. Currently, the use of BBs in hypertensive patients is limited to those with clear indications such as concomitant atrial fibrillation or heart failure, due to its inferiority in lowering CBP compared to other antihypertensive agents. For those with coincident indications for BBs, or those with contraindications to other classes of antihypertensives, having a secure alternative first-line drug would be beneficial. This study is expected to give evidence for, or against, the use of BBs in hypertensive patients in terms of lowering the CBP in addition to PBP. 5. Clinical trial monitoring Monitor personnel designated by the investigator to obtain quality test data will review the clinical trial data at appropriate intervals to ensure accuracy, completeness, and compliance with the protocol. The monitoring personnel can investigate all documents and essential records held by clinical investigators or clinical trial laboratories, including the medical records (office, clinic, and hospital) of the subjects participating in the clinical trial. Clinical investigators and researchers should allow access to these records to the monitoring personnel. The monitoring plan will be conducted three times in total, at the time of registering the number of subjects corresponding to 50% or more of the total enrollment number, when the completed research subject reaches 70% or more, and immediately before the end of the study.