MDCT FFR – fractional flow reserve
FFR – fractional flow reserve is a method used to assess the hemodynamic significance of narrowing of cardiac (coronary) blood vessels.
The heart as a vital organ and the central organ of blood circulation, as well as all other organs and tissues in the body are fed by oxygen from the blood which reaches the target tissues and organs through blood vessels, so the heart has its own arterial blood vessels called coronary arteries.
Atherosclerotic damage to coronary blood vessels and their narrowing can occur under the influence of genetic and difference factors that can occur during life.
- high blood pressure
- elevated blood sugar and cholesterol
- insufficient physical activity
Narrowing of blood vessels can be:
- mild – non-life threatening
- severe – life-threatening
In severe cases, the heart as an organ does not receive enough oxygen, which can lead to permanent damage, ie. death of heart tissue – heart attack, which can be fatal or lead to permanent heart damage that significantly disrupts the quality of life and reduces life expectancy.
What is MDCT FFR – fractional flow reserve
FFR (fractional flow reserve) is a method used to assess the hemodynamic significance of narrowing of the heart (coronary) blood vessels. It is defined as the ratio of the maximum flow that can be achieved at the site of narrowing in the coronary blood vessel and the maximum flow that can be achieved in the same coronary blood vessel as when it is undamaged – normal.
FFR is expressed as a numerical value which, if it is below a certain level, can be reliably concluded that the narrowing significantly affects the blood flow to the heart muscle.
It is the gold standard in assessing the severity of damage to coronary blood vessels during invasive coronary angiography – coronary angiography. In that way, it enables finding damage that causes insufficient blood supply to the heart muscle and can be subject to revascularization, which reduces the number of unwanted coronary events (angina pectoris, heart attack, sudden cardiac death) and prolongs survival after coronary intervention.
What are the normal values of FFR
The normal value of FFR is 1.0. FFR values greater than 0.8 indicate that the narrowing has minimal hemodynamic significance and no revascularization should be performed.
FFR values less than 0.75 indicate that the narrowing has hemodynamic significance and revascularization should be performed.
When values are determined, treatment decisions are made based on clinical assessment.
How is FFR performed?
Classical FFR is performed during coronary angiography in the Cath-lab. It is a minimally invasive procedure for imaging the blood vessels of the heart with the help of ionizing radiation, contrast agents and special devices that in the case of FFR represent a special catheter, a wire for measuring blood vessel pressure and the use of appropriate drugs that cause increased blood flow to coronary vessels and their expansion.
MDCT FFR or multidetector computerized tomographic fractional flow reserve – is a new non-invasive radiological examination used to assess the hemodynamic significance of narrowing of coronary blood vessels.
The difference between classic FFR and MDCT FFR
It is a counterpart to the previously known extravagant technique of measuring FFR when performing classical coronary angiography – coronarography that uses specially designed devices (wires) that are placed directly into the coronary blood vessels and are connected to a monitor that displays the obtained FFR values.
Za razliku od klasičnog FFR, MDCT FFR se bazira na MDCT koronarografiji nakon koje se uz pomoć dobijenih podataka vrši kompleksa matematička analiza podataka na osnovu matematičnog modela dinamike fluida. Nekoliko studija je pokazalo da je MDCT FFR validna, klinički pouzdana i komparativna metoda sa klasičnim FFR. U odnosu na samo MDCT koronarografiju, MDCT FFR pokazuje veću preciznost u proceni hemodinamske značajnosti stenoza na koronarnim krvnim sudovima.
Unlike classical FFR, MDCT FFR is based on MDCT coronary angiography, after which based on the obtained data a complex mathematical analysis of data is performed based on a mathematical model of fluid dynamics. Several studies have shown that MDCT FFR is a valid, clinically reliable and comparative method with classical FFR. Compared to MDCT coronary angiography alone, MDCT FFR shows greater accuracy in assessing the hemodynamic significance of coronary stenosis.
Limitations of the MDFT FFR
The limit of MDCT FFR is the technical quality of the obtained tomograms when performing MDCT coronary angiography, metal objects that give artifacts when recording ( the pace-maker ), moving the patient during the examination.
MDFT FFR is still not performed in acute cases.