Coronary Physiology to Guide Percutaneous Coronary Intervention: Why, When, and How

Over most of the history of interventional cardiology, it has been tacitly assumed that once flow-limiting coronary disease had been documented, angiography was sufficient to plan percutaneous coronary intervention (PCI) and, subsequently, to decide if an optimal procedural result had been achieved. This view has been challenged by recent studies evaluating the results of PCI with fractional flow reserve and nonhyperemic pressure ratios. Evidence has accumulated showing that suboptimal functional PCI results occur frequently despite a good angiographic result and that they are associated with worse patient outcomes. In this article, we discuss how available coronary physiology tools, either guide wire or image-based, may address this problem by facilitating better procedural planning and PCI precision and optimization.