The purpose of this study is to compare an angiotensin II receptor antagonist (candesartan cilexetil- Blopress®) and a calcium channel blocker (amlodipine besilate- Norvasc®/Amlodin®) in terms of the incidence of cardiovascular events among high-risk hypertensive patients.

Hypertension continues to be a major public health issue in the world. To combat this problem, many antihypertensive drugs have been developed and proven effective at controlling blood pressure in the last half century. In recent decades, antihypertensive drugs have been shown to have cardiovascular benefits beyond the reduction of blood pressure, and the focus has shifted to clarification of these effects. Angiotensin II receptor antagonists and calcium channel blockers are the most widely used antihypertensive drugs in Japan. However, these two classes of drugs have not yet been compared with respect to their efficacy for treating cardiovascular events.

Comparison: Response-dependent dose titration and blinded assessment of endpoints in high risk hypertensive patients treated with either an angiotensin II receptor antagonist (candesartan cilexetil) compared to a third-generation calcium channel blocker (amlodipine besilate).

Inclusion Criteria:

• Systolic blood pressure (SBP) ≥140 mmHg in those <70 years old or ≥160 mmHg in those ≥70 years old or diastolic blood pressure (DBP) ≥90 mmHg in a sitting position on two consecutive measurements at clinic

• At least one of the following risk factors:

  • SBP ≥180 mmHg or DBP ≥110 mmHg on two consecutive visits;
  • Type 2 diabetes (fasting blood glucose ≥126 mg/dl, causal blood glucose ≥200 mg/dl, HbA1c ≥6.5%, 2 hours blood glucose on 75 g oral glucose tolerance test [OGTT] ≥200 mg/dl, or current treatment with hypoglycemic agent);
  • History of cerebral hemorrhage, cerebral infarction, or transient ischemic attack until 6 months prior to the screening;
  • Thickness of the posterior wall of left ventricle or thickness of the wall of interventricular septum ≥12 mm on echocardiography or Sv1＋Rv5 ≥35 mm on electrocardiography, angina pectoris, and a past history (≥6 months before giving informed consent) of myocardial infarction;
  • Proteinuria ≥＋1 or renal impairment (serum creatinine ≥1.3 mg/dl) within 3 months at the time of giving informed consent;
  • Arteriosclerotic peripheral arterial obstruction (Fontaine class ≥2); *Clinical diagnosis of Alzheimer's disease.

Exclusion Criteria:

• SBP ≥200 mmHg or DBP ≥120 mmHg in a sitting position
• Type I diabetes mellitus
• History of myocardial infarction or cerebrovascular accidents within 6 months prior to the screening
• Percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG) done within 6 months of screening or scheduled
• Current treatment for congestive cardiac failure (New York Heart Association [NYHA] functional class II or severer) or ejection fraction <40%
• Coronary artery disease requiring αβ blocker or calcium channel blocker
• Atrial fibrillation or atrial flutter
• Renal dysfunction (serum creatinine ≥3 mg/dl)
• Hepatic dysfunction (AST and/or ALT ≥100 IU/l)
• A history of malignant tumor within 5 years of enrollment or suspected
• Contraindication for candesartan cilexetil or amlodipine besilate
• Pregnancy, possible pregnancy, or plan to conceive a child within 5 years of enrollment
• Not suited to the clinical trial as judged by a collaborating physician
• Inability to give informed consent