INVEST: INternational VErapamil SR Trandolapril STudy

Overview

Because blood pressure affects the heart, blood vessels, kidneys, and the entire body, it is important to keep it as normal as possible. There are several different ways to control blood pressure and to prevent or limit the development of heart disease due to high blood pressure. The purpose of this study is to compare two treatments to see how well they work and the difference in their side effects. One treatment includes the use of a calcium antagonist drug (Isoptin sustained release \[SR\] or Verapamil SR). The other treatment excludes the calcium antagonist and may include a non-calcium antagonist drug called a beta blocker (Tenormin or Atenolol). Both treatments may also include medication called angiotensin converting enzyme (ACE) inhibitors and water pills. None of the drugs in this study are experimental, they are all approved by the Food and Drug Administration (FDA).

INVEST is an investigator initiated international, prospective, randomized study comparing two pharmacotherapy strategies to control hypertension in ambulatory patients with coronary artery disease (CAD). One strategy, the calcium antagonist care strategy, centers on a calcium antagonist (verapamil SR) followed by addition of an ACE inhibitor (trandolapril) and then diuretic (hydrochlorothiazide) as needed to achieve target blood pressures (BP). The other strategy, the non-calcium antagonist care strategy, uses a beta-blocker (atenolol) followed by addition of low-dose diuretic and then an ACE inhibitor (trandolapril) as needed to reach target BP. In either strategy additional drugs can be added provided the calcium antagonist is retained in the calcium antagonist care strategy and calcium antagonists are omitted in the non-calcium antagonist care strategy. The study is organized into 15 international regions with about 1,500 study investigators randomizing approximately 22,000 patients who will be treated for at least two years. The primary response variable is the occurrence of adverse outcome, defined as any of the following events: all cause mortality, nonfatal MI or nonfatal stroke. A number of secondary response variables, including newly diagnosed diabetes will also be evaluated. The primary objective of this trial is to examine the hypothesis that the risk for adverse outcomes (all cause mortality, nonfatal MI or nonfatal stroke) in hypertensive patients with CAD is at least equivalent during treatment of hypertension with a calcium antagonist strategy when compared with a non-calcium antagonist strategy. Unique features of INVEST are, in addition to its size and international scope, its design to mimic standard clinical practice and its all electronic online data entry, drug distribution system, study management system, and electronic physician compensation. This system will permit the entire trial to be conducted via the Internet. This design is believed to be a forerunner of clinical trials research for the future.