RCIS Practice Test 2026 – All-in-One Exam Prep

The statement is true. Fractional flow reserve (FFR) is a physiological measurement used to assess the severity of stenosis in a coronary artery. It is defined as the ratio of the maximum blood flow through a narrowed artery (i.e., in the presence of stenosis) to the maximum blood flow through a normal artery (i.e., in the absence of stenosis).

This concept is crucial in determining whether a stenosis significantly impairs blood flow to the myocardium, which can guide decision-making regarding interventions such as balloon angioplasty or stenting.

The other options don't fully encompass the established definition and clinical utility of FFR. While FFR does have certain conditions under which it is measured, the measurement itself is specifically focused on the maximal flow comparison, making "Only under certain conditions" misleading. Similarly, the size of the vessel can affect absolute blood flow measurements, but it does not change the basic principle behind the definition of FFR. Thus, the core definition remains accurate and validates the selection of true as the correct answer.