The US Food and Drug Administration has cleared the marketing of the HeartFlow FFR-CT software, which permits health care professionals to non-invasively evaluate blood flow in the coronary arteries of patients showing signs and symptoms of coronary artery disease.
Fractional flow reserve (FFR) is an important piece of clinical information health care professionals use to determine the extent of a blockage in the heart or a coronary artery. Obtaining this value requires an invasive procedure called cardiac catheterisation. The HeartFlow FFR-CT software can non-invasively provide an estimate of FFR using data from a computed tomography (CT) scan of the patient’s heart. The health care professional uses the estimate, along with other clinical patient data, to determine the likelihood that the actual FFR is below accepted limits and whether or not a more accurate FFR assessment using cardiac catheterisation is necessary.
“HeartFlow FFR-CT is a computer modelling program that provides a functional assessment of blood flow in the coronary arteries from detailed anatomical data,” says William Maisel, deputy director for science and chief scientist in the FDA’s Center for Devices and Radiological Health. “This non-invasive method is an additional tool for clinicians who are considering the risks and benefits of invasive coronary procedures.”
The HeartFlow FFR-CT software is housed at HeartFlow’s headquarters in Redwood City, California. A health care professional electronically sends the patient’s CT scan data to HeartFlow where a case analyst creates 3D computer models of different sections of the patient’s heart and runs a blood flow simulator program on the models. After analysing the data and the models, the case analyst electronically sends a report with the estimated FFR values (called FFR-CT values) displayed as colour images of the patient’s heart.
The FDA reviewed the data for HeartFlow FFR-CT through the de novo premarket review pathway, a regulatory pathway for some low- to moderate-risk medical devices that are not substantially equivalent to an already legally marketed device.
Data submitted to support the safety and effectiveness of HeartFlow FFR-CT included clinical studies that compared FFR-CT measurements to FFR values directly measured by cardiac catheterisation on subjects with suspected coronary artery disease who were therefore referred for catheterisation and FFR. The results showed that Heart Flow FFR-CT was able to correctly identify 84% of the significant blockages identified by FFR as requiring intervention, and 86% of blockages identified by FFR as not requiring intervention. The company also submitted data and information showing how they have mitigated risks associated with the device, such as controlling for erroneous calculations that can lead to delayed or improper treatment.