Stents May Not Help Treat Clogged Kidney Arteries
New research raises serious questions about a very common medical procedure — placing a stent to prop open a narrowed kidney artery. A study found that people treated with these stents plus various heart drugs fared no better than people treated with medicines alone.
"Doctors are doing this procedure in the absence of good clinical evidence" and that should stop, at least for patients like those in this study, said Dr. Robert Harrington. He is a Stanford University cardiologist and program chief for the American Heart Association's scientific conference, where the study was discussed on Monday.
Stents are tiny mesh scaffolds pushed into narrowed, hardened arteries to help keep them open. They are widely used and known to help treat clogged heart arteries, but their value for some other types of blood vessels is less clear.
Narrowed kidney arteries plague 1 to 5 percent of people with high blood pressure, and as many as 7 percent of all people over age 65.
The problem can cause high blood pressure or make it worse, which raises the risk of heart attacks, strokes and kidney failure.
Stents seemed to be a reasonable thing to try to keep blood flowing to the kidneys, and at least 40,000 of these operations are done each year in the United States alone. Two previous studies surprisingly found no benefit, but many doctors disregarded those results because the patients had relatively mild blockages.
The new study tested stents in people who had lost more than half of the normal diameter of the artery because of built-up plaque in the blood vessel's wall.
Dr. Christopher Cooper of the University of Toledo and others around the country gave nearly 1,000 patients stents plus a combination of heart drugs or medicines alone. Nearly four years later, about 35 percent of both groups had experienced a heart attack, stroke, hospitalization for heart problems, death from heart or kidney disease or needed dialysis because of failing kidneys.
The result "establishes beyond a reasonable doubt" that stents are futile for people like those in this study, Dr. John Bittl of Munroe Regional Medical Center in Ocala, Fla., writes in an editorial published online with the study in the New England Journal of Medicine.
The particular combination of drugs used in the study proved better than expected, and patients were given them for free, which helped ensure they were taken, he noted.
Stents "seemed to be a reasonable approach," but the new study casts strong doubt on that, Harrington said.