Angiography-derived FFR GPS in Predicting Post-PCI Physiological and Clinical Outcomes

Physiological coronary lesion evaluation such as fractional flow reserve (FFR) is now recommended by guidelines to guide percutaneous coronary intervention (PCI). However, it was not widely used in subsequent years for a variety of reasons, including the additional time needed to measure pressure wire-derived FFR, technical challenges and the small risk associated with maneuvering a pressure wire down a coronary artery, the added time to assess multiple vessels, issues with drift in the pressure wire reading, and the time, expense, and associated side effects with some hyperemic agents necessary to measure FFR.

In recent years, advancements in technology made it possible to calculate FFR from conventional coronary angiography without the need of a pressure wire or hyperemic agent. The FAVOR III (Comparison of Quantitative Flow Ratio Guided and Angiography Guided Percutaneous InterVention in Patients With cORonary Artery Disease) China has demonstrated that angiography-derived FFR (angio-FFR) improved outcomes for PCI compared with a standard angiography-guided strategy.

Like FFR, angio-FFR is also performed in a binary manner to determine whether a vessel requires intervention and does not automatically indicate the haemodynamic improvement that would be expected post stenting. However, one advantage of angio-FFR is that virtual pullback could be generated during its calculation. Most importantly, though hyperemic blood flow was applied in angio-FFR calculation, it was predicted from resting flow with mathematical algorithm. As resting flow is more constant, consistent, and predictable across different stenoses, then resting pressure changes measured along the length of a vessel will be more predictable. Using this property, a physiological vessel map could be produced with angio-FFR by co-registration the pullback onto coronary angiogram, which not only highlight functional significant lesions and lesion locations, but also offer the possibility of prospective simple computerized virtual PCI to assess the potential hemodynamic impact before actual stent implantation.

In this regard, the investigators aim to calculate angio-FFR and to develop an angio-FFR pullback. And the investigators hypothesize that angio-FFR-derived pullback would be possible to produce a physiological map showing lesion severity and location, in addition, it could be used to perform virtual PCI and predict the physiological impact of stenting; the physiological map could be used to measure physiological lesion length and intensity.