More often than not, patients suspected of having some sort of coronary artery illness fall through the cracks when stress tests are involved. In some cases patients just aren't physically able to endure these tests and some are apprehensive about taking stress tests in general. Older patients, who aren't physically active, present a bit of a challenge too.
But two new studies are proving that there is a simpler, more accurate test that can diagnose significant coronary artery disease (sCAD) that can be done in roughly four minutes and several deep breaths.
The studies completed by Rabin Medical Center (Tel Aviv, Israel) and Washington Hospital Center (WHC; Washington) evaluate Spirocor's (Israel) respiratory stress test.
The test uses a pulse oximeter (PPG) to measure a patient's blood flow in the finger in response to his or her paced breathing for 70 seconds. PPG data captured in the study are recorded immediately and analyzed using a proprietary algorithm that determines the respiratory modulation response in a percent value.
“The test is very simple,“ Ron Waksman, MD, Associate Director, Division of Cardiology and Director of Experimental Angioplasty & Emerging Technologies for the Cardiovascular Research Institute (CRI) at WHC told Medical Device Daily. “It's relatively non-expensive and it's an office-based procedure. You don't have to take off your jacket or run. You can sit instead of stand, all you're asked to do is inhale and exhale several times.“
Waksman also served as lead investigator of the study which occurred in the U.S.
He said that the other barriers and issues that patients face is that some tests have isotopes that are injected into the body, which is unsettling for some patients. He added that this new test would not only eliminate some of that uneasiness, but it would also provide a significant boost in savings and a reduction of costs for physicians and cardiologists.
So far, data from the two studies seems to indicate that this test is quite effective.
In a study at the Rabin Medical Center, researchers found that patients with sCAD had a lower RMR compared to patients without, regardless of their risk factors or clinical history of angina, previous myocardial infarction (MI), or angioplasty. These published in the most recent issue of Euro Intervention Journal, demonstrate that RMR was lower in patients with sCAD compared to those with non-significant CAD (P<0.0011), regardless of their risk factors or clinical history of angina, previous MI, or angioplasty.
According to researchers from the Washington Hospital Center, the two studies had near similar results. In Waksman's study 150 patients used the test prior to going to catheterization labs.
“We performed Spirocor's respiratory stress test prior to an angiogram and regardless of the results we did one following the angiogram.“
Waksman said that he was pleased with the results. The study he took part in was published in the Cardiovascular Revascularization Medicine paper published back in January.
In the study, sCAD was found in 36 of the 150 patients and data results seemed show that Spirocor's test was a “ strong independent indicator of sCAD“ with an odds ratio of 95%.“
“The results are much better than what we're seeing in stress tests,“ he said.
The test still has to gain FDA approval before it can be put on the market and that could take some time, but Waksman said the device has already been in four studies and the results look pretty promising.
The safety and efficacy of the test compared to stress electrocardiography in detecting sCAD is the subject of yet another pivotal study, the 1,000-patient SCORE (Spirocor Coronary Outcome by Respiratory stress Examination), which is ongoing.
When and if the test goes to market, then it would have the ability to change how physicians test for cardiac disease, Waksman told MDD.
“I think there is great potential with this test,“ he said. “I think we're going to find more and more patients suffering from cardiovascular disease that would typically fall between the cracks because of the barriers other stress tests cause.“
Omar Ford, 404-262-5546;