Non-hyperaemic coronary pressure measurements to guide coronary interventions

Evidence supporting the use of coronary physiology as an adjunct to coronary angiography to guide percutaneous coronary interventions has accumulated over the past 25 years. The fractional flow reserve has dominated this evolving physiological guidance of coronary intervention and its use is supported by large clinical outcome trials. However, despite clinical practice guidelines advocating its use in most patients with coronary stenosis who are eligible for coronary intervention, the uptake of a physiology-guided approach remains limited. The use of non-hyperaemic coronary pressure measurements to guide coronary interventions was introduced in an attempt to simplify the routine application of coronary physiology-guided intervention in daily practice. Over the past decade, a large scientific effort has focused on the development of several non-hyperaemic pressure ratios. In this Review, we detail the basic principles of coronary physiology in non-hyperaemic conditions, the rationale for the use of non-hyperaemic coronary pressure measurements for stenosis evaluation, the current evidence base for the available non-hyperaemic coronary pressure ratios, the basis for the discordance between non-hyperaemic coronary pressure ratios and fractional flow reserve, and the potential advantages of these new parameters over fractional flow reserve.