Some drugs that drop blood pressure can help prevent heart disease from getting worse in patients with lower blood pressure who would not routinely be given such medicine, researchers reported Tuesday.
“This is the first study to demonstrate that blood pressure reduction can slow or halt the buildup of plaque in the coronary arteries,” said Steven Nissen, a cardiologist at the Cleveland Clinic.
“Previously, only cholesterol-lowering drugs have been shown to slow disease progression. The current study demonstrates that blood pressure-lowering drugs produce similar benefits,” he added.
The research was funded by Pfizer Inc., maker of Norvasc, a calcium channel blocker which was one of the drugs used in the research published in this week’s issue of the Journal of the American Medical Association.
Heart attack risk lowered by 31 percent
The study involved 1,991 patients at 100 centers in the United States, Canada and Europe. A third of the patients were given amlodipine, sold as Norvasc, a third got enalapril, an angiotensin-converting enzyme or ACE inhibitor sold by Merck & Co. Inc. as Vasotec and a third received an inert placebo.
At the beginning of the study the patients had an average blood pressure of 129 over 78 — in the middle of a range considered “prehypertensive” where patients are urged to make lifestyle changes but are not normally given drugs.
After two years the drugs had lowered the average pressure among those taking them to about 124 over 76.
Those on amlodipine had a 31 percent lower risk of heart attack, stroke, death or the need for angioplasty or bypass surgery compared to the no-drugs group, the study said. There was a smaller and less significant 15 percent reduction in such disease complications for those on enalapril.
“The reduction in risk for the amlodipine group was surprisingly large,” said Nissen.
“The patients in this trial were treated with the best existing therapies — 84 percent received cholesterol-lowering drugs and 95 percent received aspirin. Their blood pressures were already well below current treatment guidelines. Yet adding amlodipine to state-of-the-art medications further reduced cardiovascular events ...,” he added.
He said the study indicates that lowering blood pressure is critically important for patients with heart disease and it may mean that current blood pressure guidelines do not go low enough in setting targets.
Calcium blockers lower blood pressure by stopping the transport of calcium into the muscle cells lining coronary arteries. Because calcium works in muscle contraction, blocking it relaxes artery muscles and dilates the arteries.