Clinical Utility of FFR
Patients with coronary artery disease have blockages in the arteries that supply the heart muscles and these are identified during diagnostic coronary angiogram which forms the basis of most decisions whether the patient needs coronary angioplasty (stenting), bypass operation or just medications alone.
The blockages are assessed visually and the narrowings described as mild (1-49%), moderate (50-69%) or severe (70% and above). In patients with mild blockages, treatment with medications is usually sufficient.
The decision to perform coronary angioplasty (stenting) or go for bypass surgery in a patient with angina is usually very straightforward if the severity of the narrowing is >70% and in a location that supplies a large area of the heart (myocardium).
However, if the blockages are in the moderate (50-69%) range, the hemodynamic significance of these blockages (i.e whether these blockages are the true cause of the angina) is unknown and thus makes it difficult for the cardiologist to decide if he should perform coronary angioplasty or just treat it with medications.
To better understand and objectively quantitate the functional severity of a coronary blockage (stenosis) , FFR is often used.
What is FFR?
FFR is a lesion specific physiological index that defines the hemodynamic severity of the coronary stenosis. It accurately identifies blockages responsible for ischemia (lack of oxygen to the heart muscles) that in many cases coronary angiography or intravascular ultrasound (IVUS) would not have detected or correctly assessed.
FFR is determined by a carefully calibrated sensor that measures the blood pressure upstream and downstream (before and after the block) after the administration of medicine like adenosine to induce maximum flow.
FFR describes the ratio of the maximum achievable flow in the presence of a stenosis to the theoretical maximum flow in the same vessel in the absence of a stenosis. It takes into account the following factors before providing a functional severity of the coronary artery stenosis.
- The length and degree of narrowing of the coronary stenosis
- Presence of serial stenosis along the same vessel
- Size of the vessel
- Presence of collateral circulation
- Size of the perfusion territory
- Size of the vessel
FFR measurement correlates to the likelihood of ischemia with a validated cut-off value of:
If the FFR is >0.75, the interventional cardiologist can safely defer stenting the moderately narrowed but hemodynamically insignificant blocked artery. Medications with blood thinners like Aspirin or Clopidogrel and cholesterol lowering medications like statins will be sufficient.
What are the benefits to the patient?
The benefits of FFR to the patient include:
- Answers the question if the patients needs a stent, bypass surgery or be treated with just medications.
- Reduces inappropriate care with stenting of non-functionally significant blockages or failure to treat hemodynamically significant blockages that can cause angina or heart attack.
- Reduces mortality and heart attack at one year by 34%.
- Reduces procedure time for patient and contrast usage.
- Cost-effective and reduces costs for patient.
What is the clinical evidence and advantages of FFR?
FAME STUDY
Fractional Flow Reserve vs Angiography in Multivessel Evaluation
What are the benefits to the patient?
The benefits of FFR to the patient include:
- Answers the question if the patients needs a stent, bypass surgery or be treated with just medications.
- Reduces inappropriate care with stenting of non-functionally significant blockages or failure to treat hemodynamically significant blockages that can cause angina or heart attack.
- Reduces mortality and heart attack at one year by 34%.
- Reduces procedure time for patient and contrast usage.
- Cost-effective and reduces costs for patient.
What is the clinical evidence and advantages of FFR?
FAME STUDY
Fractional Flow Reserve vs Angiography in Multivessel Evaluation
More information
Using a pressure wire in percutaneous coronary interventions (PCI)
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