Breaking Hearts

Heart Flow has raised $467 million for a test to detect heart disease. Problem: It might not make patients better off.

- Ellie Kincaid

John Stevens’ corner office in Redwood City, California, has a nice view of the San Francisco-Oakland Bay Bridge. His desk, though, is a hand-me-down, and the cracked leather upholstery on the chairs reveals their history as Ikea floor models. “We can probably afford some new chairs now,” he says.

You’d think. Heart Flow, the health-tech startup of which Stevens is chief executive and president, has raised $467 million, most recently at a $1.5 billion valuation, from investors such as Wellington Management, Baillie Gifford & Co, GE Ventures and Blue Cross Blue Shield Ventures, according to Pitch book.

The valuation is based on a big idea: A noninvasive test that peers into a patient’s coronary arteries to see how blocked they are. Right now, such a test involves threading a catheter from the groin up to the heart and measuring blood flow, a slightly risky procedure called fractional flow reserve (FFR) that is done a million times a year worldwide to decide whether a patient needs a stent to open a clogged artery. Using software trained with a deep learning algorithm, Heart Flow says it can get a similar measurement from a CT scan, a lower-risk, three dimensional picture of the heart constructed with X-rays. Medicare reimburses Heart Flow $1,450 per test.

“This will be the most effective way of looking at cardiovascular disease and safer than anything else on the market,” says Bill Weldon, Heart Flow’s chairman and the former chief executive of Johnson & Johnson. “And when you put those together, it’s a combination you can’t beat.” He sees the test being used routinely.