Is Coronary Physiology Assessment Valid in Special Circumstances? Aortic Stenosis, Atrial Fibrillation, Left Ventricular Hypertrophy, and Other

With the dramatic increase of FFR use in the cath laboratory coupled with the more recent emergence of NHPRs, accurate interpretation of these hemodynamic indices has become paramount. As additional evidence supporting the use of NHPRs emerges, more clinicians are using these indices in addition to FFR or in-lieu of FFR when relative or absolute contra-indications exist to induce hyperemia. However, both FFR and NHPRs have limitations that operators need to be cognizant of. Particular clinical and procedural scenarios may call for use of one over the other. For example, FFR seems to have more accuracy and reproducibility in those with AF undergoing evaluation of an intermediate lesion, whereas the future may show iFR to be superior to FFR when evaluating which lesion in series has a higher ischemic burden. Importantly, the outcome data for use of FFR or NHPRs in patients with special clinical scenarios are limited, let alone using one over the other in these scenarios. Ultimately, the goal moving forward in patients undergoing physiologically guided revascularization is accuracy, reliability, and translation to improvement in clinical outcomes. Understanding pitfalls, limitations, and strengths for FFR and NHPRs will help guide us to that goal.