Area hospitals move to noninvasive tests for cardiac disease
Amit Patel, MD, seen through a CT scanner. Photo courtesy of University of Chicago Medicine.
Move over stress test. The treadmill test for heart disease, though common, can be costly and time-consuming; sometimes with inaccurate results. Now, new noninvasive options for heart disease testing are emerging, as Chicago-area hospitals move to technologies such as imaging and genetic testing.
The stress test involves running on a treadmill and measuring blood flow with an electrocardiogram (EKG) to detect significant blockages. But the test is often inaccurate, so patients with positive results must then get a coronary angiogram. In this invasive and expensive test, a catheter is inserted into the groin and pushed through a blood vessel to the heart.
At many local medical centers, new noninvasive tests give patients more options and lower costs.
Cardiac CT Angiography
The treadmill test’s accuracy can be improved by replacing the EKG with ultrasound or radioisotopes, but high numbers of inaccuracies still exist, according to Daniel Sullivan, MD, a cardiologist at Elmhurst Hospital.
In many cases, heart patients can take an alternative to the stress test, called cardiac CT angiography, which uses a computed tomography (CT) scan to detect blockages that restrict blood flow.
The CT scan is a sophisticated, powerful X-ray that gives a 3-D, cross-sectional view of internal organs, although the radiation dose from a CT can be much higher than a single X-ray.
“This test is equal to or possibly more accurate and more cost-effective than the stress test,” Sullivan says. “There’s still a place for the stress test, but its utility will be declining in the future.”
Several local hospitals are using the cardiac CT test, but Elmhurst Hospital uses it in its emergency room, Sullivan says. Less than 15 percent of ER patients with chest pain currently get the test at Elmhurst Hospital, Sullivan says, but the hospital would like to increase that figure to 50 to 60 percent of patients. Patients like the new test because it takes less time than the stress test, and more of them are sent home without needing further testing, he adds.
Insurers used to be reluctant to pay for cardiac CT angiography, but they have changed their minds due to promising study results in the emergency room and outpatient areas, Sullivan says. According to CostHelper—a comparison-shopping website—the typical cost of CT angiography is $500–$1,000 for uninsured patients, which is less than the $1,000–$5,000 price tag for the treadmill test.
256-Slice CT Angiography
Over at University of Chicago Medicine, physicians are using an advanced version of cardiac CT angiography called the 256-slice CT. The device “allows you to image more of the heart in a single spin of the CT scanner,” says Amit Patel, MD, a cardiologist at the hospital.
This means less radiation, less contrast material injected into the bloodstream and fewer problems getting a clear image, Patel says. The charge for the 256-slice CT is the same as for the regular cardiac CT test, he adds.
Computer Simulation Using HeartFlow
Building on CT scans, computer simulations can give physicians even more information about a patient’s heart. The HeartFlow test, used at Loyola Medicine, is a noninvasive screening that has been heralded as a significant breakthrough in cardiac testing.
While CT angiography can detect blockages in the arteries, it cannot measure how much the flow of blood has been reduced—a key factor in diagnosing heart disease. HeartFlow’s software uses CT images to build a model of the heart and simulate the blood flow.
“Comparative studies have shown that HeartFlow reduces the cost of care and decreases the number of invasive angiograms,” says Loyola cardiologist Mark Rabbat, MD.
Several studies on HeartFlow show promising results, but Patel says it’s too early to judge just how effective it is. Sullivan, on the other hand, is impressed with HeartFlow, but says the one- to two-day turnaround time bars use in ERs.
Genetic Tests that Predict Heart Disease
Also helping to diagnose certain types of heart disease is the use of genetic testing, says Marion Hofmann-Bowman, MD, PhD, a cardiologist at the University of Chicago Cardiovascular Genetics Clinic.
One such genetic test screens for a thoracic aortic aneurysm—an enlarged main artery that can burst and cause instant death. This is what happened to John Ritter, the star of the TV show Three’s Company, who died at age 54. His father, country music singer Tex Ritter, also died of a heart attack suspected to be caused by an aortic aneurysm.
The genetic test can identify which relatives have the gene for the disease and also predict how the disease will progress, allowing for early therapeutic intervention, Hofmann-Bowman says.
This testing can be expensive, however. The charge for testing the first family member is $1,000–$5,000, and tests of subsequent family members cost about $400–$900. Insurance coverage is spotty, according to a 2013 study in Circulation.
In many cases, the newer non-invasive tests are more accurate and cheaper than the traditional treadmill stress test. These new heart tests hope to take the stress out of the stress test.