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. Non-hyperaemic pressure measurements have emerged as a useful tool to guide coronary interventions and are recommended as a substitute for fractional flow reserve (FFR). In this Review, van de Hoef and colleagues explain the rationale for the use of non-hyperaemic pressure ratios instead of FFR for stenosis evaluation. Key points The loss of pressure across a coronary stenosis under non-hyperaemic conditions is intrinsically related to the vasodilatory capacity of the coronary circulation, which, in contrast to fractional flow reserve (FFR), is not informative about the degree of reduction in coronary flow attributable to the stenosis. Non-hyperaemic coronary pressure ratios provide an equivalent diagnostic efficacy as the FFR to identify myocardial perfusion abnormalities on cardiac PET perfusion studies. The use of the instantaneous wave-free ratio to guide coronary interventions results in fewer revascularizations, while maintaining non-inferior 1-year clinical outcomes, compared with the use of FFR. Alternative non-hyperaemic coronary pressure ratios have very high diagnostic efficacy compared with the instantaneous wav