Don't Judge a Book by Its Cover

In this issue of Circulation: Cardiovascular Interventions , Kang et al1 compare intravascular ultrasound (IVUS) parameters against a gold standard of fractional flow reserve (FFR) for evaluating intermediate stenoses. Their work adds another piece of evidence to a debate whose outcome is fundamentally changing interventional cardiology. As encapsulated by the title of the “FFR versus Angiography for Multivessel Evaluation” (FAME) trial,2 the debate can be summarized simply: physiology versus anatomy. Its urgency and importance cannot be more clear, given recent skepticism toward the value of percutaneous coronary intervention (PCI): its ranking as 1 of the 10 most overused procedures in a consumer report3; litigation against an interventional cardiologist for allegedly implanting inappropriate stents4; and an editorial in a prominent medical journal calling to end ad hoc PCI.5 Therefore, the work by Kang et al1 is both timely and relevant.Article see p 65The motivation to use anatomy when evaluating coronary lesions can be traced back to animal models developed more than 35 years ago. In chronically instrumented dogs with an external occluder, the coronary flow reserve fell as the lumen became progressively reduced.6 Experiments like this suggested that stenosis dimensions should be the criterion for PCI. However, a number of trials comparing outcomes in chronic angina found no survival benefit to anatomically driven PCI.7,8 Although selection bias in such studies remains a limiting factor for their generalization and may predispose the outcome toward the null hypothesis,9 it has led guidelines to recommend corroborating evidence from a functional study before PCI. …