Cholestech (Hayward, California) reported the results of a Mayo Clinic (Rochester, Minnesota) study that suggests that a non-invasive fingertip test for which it is the distributor can identify coronary disease at its earliest stages and may provide a new point-of-care test for physicians to use in their offices.
The test, called the Endo-PAT 2000, is used to assess vascular endothelial dysfunction, an early indicator of athero- sclerosis. It was developed by Itamar Medical (Caesarea, Israel).
There are about 30 studies under way to test the Endo-PAT 2000, and this most recent study's findings were published in December in the Journal of the American College of Cardiology.
Cholestech has set high expectations for the impact the test could have on cardiovascular testing. President and CEO Warren Pinckert told Diagnostics & Imaging Week that the test "could change the face of risk assessment and then monitoring people after they've had an event."
According to the Mayo Clinic, the endothelium, which is the inner lining of vessels, protects vessel walls from injury and helps modulate their expansion and contraction to maintain appropriate blood flow and blood pressure.
Endothelial dysfunction would result from damage or trauma, which would cause the wall to thicken or harden, which indicates the beginnings of heart disease. And, importantly, Pinckert noted that there are more and more studies linking endothelial dysfunction as the "first sign in the process of coronary disease."
"Endothelial dysfunction is the earliest measure of functional abnormality in the blood vessels, so coronary endothelial dysfunction signals the beginning stages of atherosclerosis and heart disease," Mayo said.
In the Mayo study, researchers investigated the value of the Endo-PAT to assess the relationship between dysfunction in the heart region and dysfunction in the extremities. Through testing the 94 patients in the study in the catheterization lab, coronary endothelial dysfunction was found in 55 patients.
Cholestech said that by comparing those results against the Endo-PAT system, "the researchers found a threshold value for the fingertip test that would have identified the majority of the patients with early heart disease."
The Mayo Clinic concluded in its study that the findings "indicate a potential role for RH-PAT as a test to identify individuals like this prior to an invasive procedure such such as an angiogram."
Mayo cardiologist Amir Lerman, MD, who led the study, said, "Atherosclerosis tends to affect all of the blood vessels in the body, and is not just limited to the arteries of the heart. We expected patients with an abnormal result in the fingertip test to also have disease starting in their coronary arteries. We found a strong correlation, and the fingertip test was very sensitive in identifying patients with early heart disease."
The device, which is the only system of its kind to gain FDA 510(k) clearance, consists of three parts. First, two disposable probes are placed on the fingers of the individual being tested by employing reactive hyperemia peripheral arterial tonometry. A portable unit connects to and operates the probes, while signal analysis and the endothelial dysfunction report are generated via a laptop computer.
The report that is generated provides a number and a "scattergram showing the volume and velocity of the blood going through the finger," Pinckert said. There is a scale vs. the volume of blood going through the vessels, and that volume has been converted into a number, which indicates whether or not there is endothelial dysfunction.
And Cholestech, whose business is focused on point-of-care testing, sees other benefits of the testing device.
"The very intriguing part of this product is that it takes about 15 minutes to run, so it will be done right in the physician's office," Pinckert said. "And it's non-invasive, so the physician doesn't have to draw blood. It doesn't have to go out to a lab to be processed."
Pinckert and his team are eagerly awaiting results of the three-generation Framingham Heart Study, which has incorporated Endo-PAT into its study. Researchers in that study already have tested the first generation, and when it is completed, the study will have looked at anywhere from 1,000 to 2,400 people, Pinckert said. Those results are expected by the end of 2005.
Although there are devices that can measure such things as elasticity of arteries, there is nothing exactly like the Endo-PAT 2000. For the FDA clearance of the Endo-PAT 2000, which was secured by Itamar in December 2003, the FDA considered the predicate of the device to be "a catheter inserted into the heart," Pinckert said.
Even with FDA clearance, Cholestech indicates that more studies will be necessary that indicate the Endo-PAT 2000 benefits as a screening tool for endothelial dysfunction. In the meantime, the company feels it has some persuading to do.
"At this point, we're approaching more our early adopters, so we'll be meeting with key opinion leaders . . . to assess opinion," Ken Miller, Cholestech vice president of sales and marketing, told D&IW. "It's probably a little early to expect real high sales at this point, any significant sales. We're just going to be developing the market in 2005."
However, he said there is a fair amount of interest in the device in the market.
The company's plan is to initially target cardiologists before marketing the device as a tool for general practitioners.
The product was introduced at the American Heart Association (Dallas) conference in New Orleans last November. The Cholestech team also will attend the American College of Cardiology's (Bethesda, Maryland) annual conference in March in Orlando, Florida.