Bay Area company develops new heart disease test


Richard Wirtenson was a few strokes from the green, when a strange feeling interrupted his round of golf. He knew he was uncomfortable, but the symptoms were vague, "I got a burning sensation across my chest," Wirtenson said. "It was not a pain."

Wirtenson's doctor, cardiologist Jeffrey Gardino, notes, "It could be gastrointestinal, it could be their lungs, or it could be heart blockage, and my job is listening to them, trying to ferret out more selective symptoms that may pinpoint whether they have heart disease."

According to Gardino, the goal is not to rush every patient into invasive tests like angiograms, which are highly effective at spotting heart blockage, but also carry side effects, "It's a lot of radiation," Gardino said. "Ten years worth of radiation you get in the course of that procedure." He says current options include pre-screening patients like Wirtenson with a cardio stress test, involving a treadmill.

But now, a Bay Area company believes it has an alternative that can help doctors spot which patients are likely to be suffering from heart disease much more quickly. The test was developed by Palo Alto-based CardioDx. It involves a simple blood draw that can be done in a doctor's office. But what happens after that actually involves some extremely sophisticated science,

"Once the blood is drawn from the patient, we bring it into our lab in Palo Alto, and it's a three step process," said CardioDx CEO David Levison. According to Levison, the first step involves automated machines that extract the RNA from the blood cells which is then used to synthesize a complete DNA sample, "And the final step is we put it on the PCR machine which measures the individual levels of 23 genes in our algorithm."

In simpler terms, he says the process is ultimately measuring gene expression. Looking for the activity of specific genes that are typically turned on when a patient's blood vessels are diseased and producing plaques that block the arteries. He says the reading gives doctors a strong indication of whether is patient is suffering from heart disease.

"With our test, we can easily and quickly identify those patients where it's very unlikely to be caused by a blocked coronary artery," Levison said. And he believes the blood test, coupled with other screening methods would significantly reduce the false positives and unnecessary angiograms, while getting patients who do need them a quicker diagnosis.

"Does someone need an invasive test or not? Or is this someone I can watch more closely for the next few months to years before having them committed to doing a test," said Gardino.

In Wirtenson's case, additional tests did eventually lead to an angiogram, which revealed a blockage. He eventually had a stent placed in his artery, allowing him to return to the golf course, "It's a small nine hole course but we really enjoy it," said Wirtenson.

The test runs just under $1,200. It is now covered under Medicare, but private insurance still varies.

Written and produced by Tim Didion

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