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From OHSU Knight Cardiovascular Institute
Maros Ferencik, M.D., Ph.D., MCR
Dr. Ferencik is the section chief of cardiovascular imaging in the OHSU Knight Cardiovascular Institute. His research focuses on the effective and efficient use of cardiac CT in the assessment of coronary atherosclerosis and coronary artery disease.
Cristina Fuss, M.D.
Dr. Fuss is the section chief for cardiothoracic imaging in the OHSU Department of Diagnostic Radiology. Her special interest is in lung cancer, both screening and therapy evaluation, as well as complex cardiac valve disease.
Fractional flow reserve computed tomography (FFR CT) is changing how we diagnose obstructive coronary artery disease (CAD) and preventing patients from needing invasive angiograms.
This virtual modeling tool, which combines functional and anatomical information, provides a new level of specificity for determining which patients with suspected CAD need intervention and which do not.
The data show that FFR CT is similar to invasive FFR for ruling our hemodynamically significant stenosis, which makes it an extremely valuable tool for avoiding unnecessary further testing for moderately stenosed patients.
FFR CT was approved by the Food and Drug Administration in November 2014. OHSU was the first center in Oregon to begin offering FFR CT in April 2019.
How it works
Using artificial intelligence and an algorithm for flow dynamics, vendor HeartFlow, Inc. analyzes CT images to calculate whether arterial narrowing is causing a blood flow problem, combining both structure and function in one test. The result is a color-coded, 3D image that details changes in blood flow across coronary lesions.
Before the CT scan, the patient receives an injection of contrast through the vein and nitroglycerine to slow down the heart rate to obtain high-quality images. Performed in an outpatient setting, the FFR CT provides a significantly better experience for the patient.
The test only takes a short time, there are no catheters, and patients are free to go about their business with less stress and risk to obtain the diagnostic results.
How it works at OHSU
At OHSU, we have a joint program between radiology and cardiology. We have optimized our coronary computed tomography angiogram (CCTA) for FFR CT evaluation. Therefore, we can perform FFR CT in all patients who undergo CCTA.
We provide a written report for the referring provider based on the findings.
Our team will use our interdisciplinary expertise to evaluate whether a patient would benefit from FFR evaluation. If so, we have a system in place for pre-authorization and reporting with insurance providers, requiring no additional steps by the referring provider.
The typical turnaround for results of FFR CT is 24-48 hours.
A triage tool gaining acceptance
The FFR CT’s purpose is to sort out the patients who do not need invasive testing or procedures.
If the test is negative, we can securely say the patient does not need an angiogram. The data thus far show those patients who have negative FFR CT do very well through two years of follow-up. However, the patient will likely still need aggressive management of risk factors and possibly medical therapy.
A positive FFR CT will typically prompt a catheter angiogram.
Because the cost analysis and data show FFR CT leads to less intervention, we are seeing an overall change in reimbursement approval. If you tried to order CCTA two years ago, you may have been denied. Now, a majority of commercial insurers and Medicare and Medicaid are recognizing the benefit of CCTA and FFR CT.
When to refer
The typical patient for CCTA has symptoms suggestive of obstructive coronary artery disease. The symptoms include chest pain or shortness of breath typically triggered by physical activity.
CCTA is best suited for patients with low to moderate likelihood of obstructive coronary artery disease.
If CCTA detects moderate or severe stenosis, FFR CT assesses the hemodynamic significance of the finding.