Routine pressure-derived fractional flow reserve guidance: from diagnostic to everyday practice.

The pressure-derived fractional flow reserve (FFR) is a valuable and well validated index for assessing the ischemic significance of coronary lesions. The 0.75 cutoff value of FFR discriminates between lesions with and without ischemic potential, helps decision making as to whether to revascularize a coronary stenosis and assists in evaluating the results of catheter-based treatment. Recent data show that the FFR index is also useful in managing patients with complex coronary disease. The aim of this paper is to provide an overview of the theoretical background of this index and its clinical applicability in the catheterization laboratory.