Medical Riddle: Is a Stent or Medication the Best Way to Treat Blocked Kidney Arteries?

What’s the best way to treat a narrowing of the blood vessel that supplies blood to the kidney? After almost 40 years of study by doctors and scientists, the answer is not yet clear for a disorder that affects millions of Americans.

To solve this problem, Saint Louis University is recruiting participants as part of a national study to measure the effectiveness of stents to treat atherosclerotic renal artery stenosis, or narrowing of the kidney arteries.SLU is seeking participants for the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) study, a $28 million study funded by the National Institutes of Health (NIH). The study is recruiting more than 1,000 participants at 100 sites around the United States. Enrollment for the study is now starting in St. Louis.People may qualify for the CORAL study if they have atherosclerotic renal artery stenosis accompanied by high blood pressure. The disease affects 1 to 3 million Americans, primarily over the age of 50, and carries a high risk of heart attack, stroke, heart failure, kidney failure and death. During the study, participants will be randomized to one of two groups. They will receive medication alone to control blood pressure and other risk factors, or they will be treated with medication and placement of a stent in the blocked kidney artery. Participants will be followed for the duration of the six-year study to determine which treatment reduces incidences of heart attack, heart failure, stroke and kidney failure. Historically, medication has been used to control high blood pressure and associated problems, said Donald Jacobs, M.D., a vascular surgeon at Saint Louis University School of Medicine who is this site’s principal investigator for the study. With advances in technology, treatments to open a blocked artery, such as balloon angioplasty and stents, have been used increasingly in kidney arteries, but without evidence that they reduce the risk of heart and kidney problems. Dr. Jacobs stated that the CORAL study will examine whether inserting a stent, or metal scaffold, to keep the artery open will lead to better outcomes overall for patients.”It’s not clear what is the best way to treat patients with renal artery disease,” Jacobs said. “With this study, we hope to have an answer.” Blockage of the kidney arteries is one of the two major causes of high blood pressure, occurring in 1 to 5 percent of patients. In patients who have accelerated high blood pressure, the prevalence of blocked kidney arteries is much higher, ranging from 10 to 40 percent.If the disease is caught early, about half of patients who have blockage in one artery benefit from opening the blockage with a stent. Physicians have tried to identify these patients who could benefit from intervention, but the disease is difficult to diagnose through imaging scans and other means. Patients may have other symptoms or problems that indicate renal artery stenosis, such as known carotid artery disease; coronary artery disease (such as angina, prior heart attack, or prior coronary artery stent or bypass surgery); or leg artery circulation problems such as pain with walking (claudication).(Source: Saint Louis University: May 2006.)