Invasive “in the cath-lab” assessment of myocardial ischemia in patients with coronary artery disease: When does the gold standard not apply?

In the present review we aim to look into the available evidence about the reliability and feasibility of FFR and iFR in clinical contexts different from stable angina where these techniques have been validated. We aim to shed light on which technique can be used to invasively assess ischemia when an angiographic moderate coronary stenosis is observed in a clinical setting other than isolated stable CAD.