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NEW YORK (Reuters Health) - People who come to the emergency department complaining of chest pain often get a test that isn't helping them very much, according to a new study.
Most of the time, the study found, people had a negative result on what's known as a stress test, but even those patients who had an abnormal result rarely received treatment or suffered a heart attack later on.
Stress tests measure how well the heart pumps blood when a person is active compared to when he is resting. Patients are usually asked to walk on a treadmill, or perform other exercise, while being hooked up to a machine that measures the heart's activity.
The results "showed something that we have thought, that we probably do stress testing too often," said Dr. Troy Madsen, a professor at the University of Utah School of Medicine, who was not involved in the research.
When someone comes to the emergency room with chest pain, doctors can prescribe a stress test to determine if the person likely has heart disease -- and therefore should be monitored in the hospital or treated with surgery or medications -- or if that person can be sent home.
Dr. Srikanth Penumetsa and colleagues, who published their findings in the Archives of Internal Medicine, sought to find out whether the practice of giving stress tests to people admitted to the hospital with chest pain was helping to pick out those who would end up having a heart attack within the month following the hospital visit.
They looked back on the medical records of about 2,100 patients who had been admitted over a two-year period to their hospital, Baystate Medical Center in Springfield, Massachusetts.
Seven out of every 10 patients received a stress test, and 12 percent of them came back with abnormal results.
Of the 184 patients who had abnormal results, 23 were given a follow up test and 10 patients ended up having a procedure such as bypass surgery or stenting, in which a balloon is used to expand a blood vessel, followed by inserting a mesh tube to keep the artery open.
Most of the follow up tests were angiograms, which involve inserting a tube into a blood vessel, dyeing the blood and x-raying the blood flow.
Madsen said he was surprised that more people didn't get a follow up test.
Penumetsa said that not all patients require an angiogram after an abnormal test, and "therefore I do not think this number should have been higher."
Within a month of being discharged from the hospital, seven patients suffered a heart attack. Three of them had undergone stress testing.
Penumetsa said the results show that stress testing does not lower the chances of having a heart attack within the next 30 days.
"Since stress testing has not been shown to decrease the risk of having a heart attack, there is no absolute need to routinely perform this test prior to discharge," Penumetsa wrote in an email to Reuters Health.
Dr. Anthony Napoli, an emergency physician at Rhode Island Hospital and a clinical professor at Brown Medical School, said a good starting place to reduce unnecessary stress tests would be with patients at low risk of having heart disease.
"They might be the one group that you could target as having a planned protocol that would say, those who are low risk don't get a stress test and just get a certain follow up," Napoli said.
"That would reduce stress test utilization, but also maintain the same safety and efficacy," he added.
Penumetsa suggested that after a brief observation in the hospital, and after a heart attack is ruled out through other tests, patients could be sent home and followed up for the next few days in an outpatient doctor's office, instead of given a stress test.
Napoli, who was not involved with the new research, said the idea of limiting stress tests to those at a higher risk of having a heart attack would need to be studied before it could be widely recommended.
Stress tests are not without their drawbacks.
They can cost upwards of $1,000 and they carry some risks.
If someone mistakenly gets an abnormal result -- called a false positive -- he could be subjected unnecessarily to an invasive procedure that carries the risk of injuring the kidneys, said Madsen.
Stress testing could result in an overdiagnosis of heart disease, "and patients could then undergo more interventions such as angioplasty or bypass surgery," said Penumetsa.
There has been concern that screening for heart disease and other conditions has led to too many diagnoses and unnecessary treatments (see Reuters Health report of February 9, 2012 and May 23, 2011).
"However, in our study, very few patients with positive tests had any interventions," said Penumetsa.
Madsen said the challenge has been to balance the hazards and costs of testing with the risk that a looming heart attack could be overlooked.
"If you're going to err on one side, people are going to err on too much testing," he told Reuters Health.
Penumetsa also that doctors' concerns over lawsuits might also be affecting their care.
"If they've ordered a stress test, then they can say that 'they've done everything possible' before sending the patient home, even if 'everything possible' doesn't actually change the outcome at all," said Penumetsa.
SOURCE: bit.ly/JZh0ip Archives of Internal Medicine, online May 7, 2012.