Study Identifies Kidney Trouble as Heart Risk
ACE inhibitor drugs improve survival
WEDNESDAY, June 28, 2006 (HealthDay News) -- A new analysis of a heart study whose original results puzzled cardiologists now identifies reduced kidney function as a health threat for people with stable coronary disease.
But, the research also identifies a specific medication that can reduce the risk.
The first results of the PEACE -- Prevention of Events With an ACE inhibitor -- trial were a surprise, because they showed no benefit from ACE inhibitor treatment for people with blocked coronary arteries, a previous heart attack or similar chronic problems, said Dr. Scott D. Solomon. He is director of noninvasive cardiology at Brigham and Women's Hospital, in Boston, and lead author of a report on the new analysis in the June 27 issue of the journal Circulation.
"That was in contrast to two similar trials, so there was a lot of confusion about why they were positive and the PEACE trial was not," Solomon said. Both of those earlier trials had found a significant survival advantage from ACE inhibitor treatment for people with stable coronary disease.
The new analysis did find such a benefit for ACE inhibitor treatment in terms of reduced incidence of new heart disease and death, but only for the 16 percent of participants with impaired kidney function, he said.
The PEACE trial used one ACE inhibitor, trandolapril (Mavik), but "given that there have been so many studies with ACE inhibitors showing similar findings for a number of indications, it is likely that this applies to all ACE inhibitors," Solomon said.
ACE inhibitors prevent the formation of angiotensin II, a molecule that constricts blood vessels. The drugs are often prescribed for high blood pressure.
The drug used in the trial was donated by the manufacturer, but the study was financed by the U.S. National Institutes of Health, Solomon said.
For people who met the definition of reduced kidney function, treatment with the ACE inhibitor reduced the death rate from all causes by 27 percent, as compared to participants given a placebo. The reduction for people with adequate kidney function was 6 percent.
One reason for the different finding was that the second analysis used a more detailed measurement of kidney function than the relatively crude method used in the initial report, the researchers said.
Another complicating factor was that the participants in the PEACE trial had less severe heart disease than those in the trials that found a benefit from ACE inhibitors, Solomon said. "It was a less sick and less risky population," he said.
Further studies are needed to fully determine the value of ACE inhibitor treatment for people with stable heart disease and reduced kidney function. But, the PEACE results indicate that "we can use renal [kidney] function to identify patients at greatest risk and who will therefore benefit from an ACE inhibitor," Solomon said. "Renal function is a very potent marker. Even a slight reduction puts patients at risk," he said.
Other studies have hinted at a role of kidney function in heart disease, "but this may be the first study to suggest a treatment differential in patients with reduced kidney function," Solomon said. "It can help guide therapy," he added.
Tests of kidney function already have begun to enter medical practice, said Dr. Nieca Goldberg, chief of women's cardiac care at Lenox Hill Hospital in New York City, and a spokeswoman for the American Heart Association.
"For the last few years, we have been looking at kidney function as a risk factor," Goldberg said. "We treat people who have kidney disease to the same level as those with other risk factors. For example, in individuals with chronic kidney disease, we try to get LDL cholesterol down to 100," she said.
LDL cholesterol is the bad kind that clogs arteries. A reading of 100 for LDL cholesterol is well below that recommended for most individuals.
To learn more about ACE inhibitors, visit the National Library of Medicine.