FFR measurement and intracoronary imaging (IVUS, OCT)

Coronary angiography shows the outline of the coronary arteries, but it does not always tell whether a narrowing truly restricts blood flow, nor what the artery wall looks like. Two types of complementary tests, performed during the angiogram through the same access, answer these questions. FFR (fractional flow reserve) measurement uses a very fine guidewire fitted with a pressure sensor, placed beyond the narrowing. The pressure beyond and before the narrowing is compared, usually after injection of a medicine that increases coronary blood flow; resting indices measured without this medicine (such as iFR) are also available. A low value means the narrowing limits blood flow and should be treated; a normal value often avoids an unnecessary stent. Intracoronary imaging shows the inside of the artery: IVUS (intravascular ultrasound) uses sound waves, while OCT (optical coherence tomography) uses light and gives a very detailed image. They make it possible to measure the artery diameter, analyse the plaque and calcium, choose the right stent size and check after implantation that the stent is fully open and well apposed to the wall. At Clinique Pasteur Tunis, these measurements are performed in a latest-generation catheterisation laboratory whenever the cardiologist considers that they will provide useful information for the decision or for the quality of the angioplasty.