Looking into the heart of the matter (Dr. Jonathon Leipsic)
It takes eight hours for the information to be sent, analyzed and returned from HeartFlow Inc’s offices in Redwood City, Calif., so it’s not used on emergency cases. Instead, patients with stable, persistent cardiac issues such as chest pain and atrial fibrillation (irregular heart beat) could get a CT scan that’s then converted to a more detailed image.
“The CT scan provides us with the anatomy and what we get from the FFRct modelling is physiology. We get flow, velocity and pressure. We know not all narrowings cause significant (blood) flow disturbance and only the significant ones need to be dealt with,” says Dr. Jonathon Leipsic, chairman of the Department of Radiology at Providence Health Care’s St. Paul’s Hospital.
It’s all done without resorting to more invasive catheter angiograms typically used to find clogged blood vessels. That procedure guides a thin tube into a coronary artery through an incision in the skin. A contrasting fluid is then injected through the catheter and it shows up on moving X-rays taken of the heart in action. An additional wire probe is added if doctors want to measure blood flow and pressure near the blockage, something FFRct imaging does through computer calculations.
Erin Ellis reports
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