Early heart disease, when fatty plaque starts to line the arteries without blocking blood flow, can trigger heart attacks and death, a finding that reverses long-thought medical views.

The study published Tuesday in the Journal of the American Medical Association has implications for about one-quarter of the 2.7 million Americans who undergo procedures each year to diagnose heart disease. That's the group of people without chest pain or signs of blockage who are often sent home with the message they are fine, said Tom Maddox, a cardiologist at the VA Eastern Colorado Health Care System in Denver.

Doctors currently divide patients into two groups, those with obstructive heart disease who need immediate treatment and those with "insignificant" blockages, Maddox said. The new findings show that rather than a sharp cutoff point, the risk of heart disease starts with early signs of plaque accumulation and increases as the buildup worsens, he said.

"There is a clear stepwise progression in the amount of coronary disease you have with the risk of having a heart attack and dying," Maddox, the lead study author, said in a telephone interview. "The main thing we need, for those doctors and patients who are disregarding these findings, is to change that. These people are still at risk for a heart attack, and some subset will go on to die."

The study analyzed the health of 37,674 U.S. military veterans who underwent elective procedures to see if their arteries needed clearing. The risk of having a heart attack was twofold to 4.5-fold higher in patients with mild plaque buildup, compared with those who had clean arteries. It was even greater among those with serious blockages, with almost 20 times more risk.

The risk of death also increased in concert with greater blockage levels, rising from 1.4 percent per year to more than 4 percent.

Maddox said he gives all his patients with signs of plaque buildup aspirin and cholesterol-lowering drugs called statins, a medicine now recommended for everyone at high-risk of heart disease. It's a reasonable approach, although specific studies are needed to prove the pills reduce their risk before such therapy is broadly mandated, he said.

The findings also help him convince people they need to stop smoking, start exercising and eat right, he said.

"This risk is no longer hypothetical," Maddox said. "I can show patients a picture of the buildup and tell them they are at higher risk for a heart attack. Before, no one knew what to do with these findings. Now we know that all coronary disease deserves attention and treatment to try to reduce the risk."