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

The statement is true because Fractional Flow Reserve (FFR) is a measurement that assesses the pressure differences across a coronary artery stenosis to determine its significance in terms of blood flow. Typically, an FFR value of greater than 0.80 indicates that the stenosis does not significantly impede blood flow and, therefore, may not require intervention.

In the scenario where there is significant collateral flow, even a considerable stenosis (greater than 70%) might not limit the blood flow to a level that results in an FFR of 0.80 or less. Collateral circulation can essentially provide an alternative pathway for blood to reach the myocardial tissue, which can mask the true severity of the stenosis as determined by FFR. This means that despite a high degree of stenosis, the presence of adequate collateral circulation can result in a higher FFR reading, suggesting sufficient perfusion and less urgency for treatment. This underscores the importance of considering both stenosis severity and collateral flow in evaluating coronary artery disease.