A new study suggests that many heart patients are scanned for potential blockages in their carotid arteries for uncertain or inappropriate reasons.
The carotid arteries, which run up both sides of the neck, deliver blood to the brain. If they become blocked, that can cause a stroke. Once spotted, a blockage can be treated with surgery or medication, the researchers said.
But among more than 4,000 VA patients in the study, scans for uncertain reasons happened more than 83 percent of the time, while scans for inappropriate reasons happened 11 percent of the time. Only slightly over 5 percent of these patients were screened for appropriate reasons, the study found.
“The vast majority were done for uncertain or inappropriate reasons,” said Dr. Larry Goldstein, chairman of the department of neurology at the University of Kentucky School of Medicine. He wrote a commentary accompanying the study.
Experts differ about who should be scanned and why they should be scanned. It is typically done using an ultrasound device that detects blockages.
Some surgeons frown on screening, and believe it’s better for certain patients to be treated with medication instead of riskier surgery.
“If you screen someone and say, ‘You’ve got a narrowed carotid artery,’ they’re going to want something done,” said Dr. Frank Veith, a veteran vascular surgeon who was not involved in the study. “But the procedures drive up health care costs, and patients can have strokes or die because of them [the procedures].”
The U.S. Preventive Services Task Force recommends that only adults who’ve had a stroke or mini-stroke should be screened.
But the study authors said other recommendations suggest certain people should be screened even if they don’t show symptoms of illness, such as those whose carotid arteries make a unique sound known as “bruit” when monitored via a stethoscope. Carotid bruit is a swishing sound heard in the artery as blood tries to move around a blockage.
In the study, led by Dr. Salomeh Keyhani of the University of California, San Francisco, researchers tracked patients — all aged 65 or older, with an average age of 74 — who underwent surgery to open their carotid arteries between 2005 and 2009. The patients didn’t have symptoms, and almost all had undergone screening.
Veith, a professor of surgery at New York University Medical Center and Cleveland Clinic, said most surgeries to open carotid arteries aren’t necessary. In general, he said, these patients would be “better served” by being treated with anti-cholesterol drugs.
How did the procedures become routine in the first place? Studies from decades ago suggested surgery in many cases, Veith explained, but they haven’t been updated in the era of medications that lower cholesterol levels.
“The old studies are now obsolete and don’t apply anymore,” he said. “New studies have to be done to show whether it’s worthwhile or not.”
Goldstein had a similar perspective.
“Clinicians do not want to miss a potential opportunity to prevent stroke. However, there is concern that the results of the prior studies may no longer be valid due to advances in medical therapy,” Goldstein said.
As for screening, Veith said it’s probably appropriate in some cases, since it can help determine who might need medication, “but not as a way to detect patients who should get operated on.”
For his part, Goldstein said the new research has some weaknesses. The main one is that it was limited to patients who underwent surgical procedures. “This is the tip of the iceberg, as it does not address the likely considerably larger population of patients who get the test and did not have a procedure,” he said.
Also, the study almost entirely looked at male veterans. Only a few dozen women were included. As a result, he said, “the results may not be generalizable to other populations.”
What should physicians do?
“Consider carefully the reason the screening test is being performed and the consequences of a positive, negative or equivocal result, and have that discussion with patients before the test,” Goldstein advised.
As for patients, they “should understand their risk factors for stroke and cardiovascular disease and, in consultation with their health care providers, take steps to reduce their risks,” Veith added.
He noted that ongoing research will offer more insight into the value of surgical procedures for carotid artery blockages versus medication.
The study is published in the April 18 issue of JAMA Internal Medicine.
For more about guidelines regarding carotid screening, try the U.S. Preventive Services Task Force.