A Randomised, Crossover Investigation to Evaluate and Compare the Effectiveness, Safety and Feasibility of a Novel Dedicated Over-The-Wire FFR Infusion Microcatheter (HYPEREM™IC) for Measuring Fractional Flow Reserve (FFR) Using Intra-coronary Non-weight Adjusted Adenosine Infusion With the Standard Intra-venous Administration of Adenosine, in Subjects With Intermediate Coronary Artery Stenosis.

Coronary artery disease is the most common type of heart disease that affects millions of people worldwide. It is caused by a narrowing or blocking of the arteries (known as stenosis) due to plaque, which restricts blood flow and reduces the amount of oxygen to the heart.

Over the past decade, fractional flow reserve (FFR) measurement has been increasingly used in cardiac catheterization laboratories, providing a straightforward and readily available quantitative assessment of the functional severity of a coronary artery stenosis, as the ability of the cardiologist to discriminate between stenoses that can cause ischemia and those that are physiologically insignificant on the basis of coronary angiography alone is limited.

Measuring FFR determines the ratio between the maximum achievable blood flow in a diseased or narrowed coronary artery and the maximum blood flow in a normal coronary artery. This ratio represents the potential decrease in coronary flow distal to the coronary stenosis.

FFR is easily measured during routine coronary angiography by using a pressure wire to calculate the ratio between the coronary pressure distal to a stenosis or a diseased segment and the aortic pressure under conditions of maximum myocardial hyperemia. An FFR of 1.0 is widely accepted as normal. An FFR lower than 0.80 is generally considered to be associated with coronary ischemia and widely accepted in favour of revascularization over conservative management.

The current standard methods of measuring FFR is to insert a pressure wire into the coronary artery while the hyperaemic agent, normally adenosine, is delivered by continuous intravenous infusion via a central femoral vein, a large ante-cubital peripheral cannula or intra-coronary bolus injection.