THE IMPORTANCE OF POST-PCI FFR: “IT’S NOT OVER ‘TIL IT’S REALLY OVER”



Barry F. Uretsky, M.D., University of Arkansas for Medical Sciences, Little Rock, AR, USA

The value of fractional flow reserve (FFR) in determining whether an intermediate stenosis lesion causes ischemia is well documented. Treating lesions with an ischemic FFR and deferring lesions with a non-ischemic FFR have been shown to improve long-term outcomes. As a result, use of FFR in evaluating angiographic intermediate lesions has a Class I recommendation by the European guidelines and a Class IIa recommendation by the American College of Cardiology (ACC)/American Heart Association (AHA). The guidelines are, however, silent on the value of measuring FFR after an angiographically successful percutaneous coronary intervention (PCI). We propose that measuring FFR post-PCI is valuable and will improve long-term outcomes. Although one might conclude that an angiographically normalized vessel after PCI will have a non-ischemic FFR, this is not always the case. There are at least three major reasons for a persistently ischemic FFR in this setting: 1) unmasking the ischemia-potential of a second unimpressive angiographic lesion, 2) underexpansion of stented areas, and 3) the presence of diffuse disease. The level of post-PCI FFR is a major predictor of long-term outcome. In three large studies comprising over 2500 patients, the level of post-PCI FFR predicted long-term outcome in each study.

In a series of 664 lesions, we noted an incidence of 21% of post-PCI ischemic FFR. The two most important associated characteristics were the presence of diffuse-but not severe- angiographic disease and a lesion in the left anterior descending artery. In our study the best cutoff point by ROC analysis for good outcome after PCI was an FFR of 0.87 or higher. In a study by Li et al, the cutoff point was 0.88. We also addressed the issue as to whether a low post-PCI FFR is simply a marker of more extensive atherosclerosis or whether the FFR can be improved by further intervention. We demonstrated that in the 137 lesions which had a relatively low FFR (0.78+0.08) and underwent subsequent intervention, FFR improved significantly (p<0.001) to 0.87+0.06 . Furthermore, of the 21% of lesions with an angiographically satisfactory PCI result and FFR< 0.80, further intervention decreased the incidence of ischemic FFR (<0.80) to 7%. Subsequent interventions included post-dilatation of the stent with a non-compliant balloon (42%), use of addition stenting in 33%, and both in 18%. In 9% the vessel was imaged with either IVUS or OCT, but due to diffuse disease was not further treated. We also demonstrated that measuring post-PCI FFR and performing additional interventions were not associated with any significant complications.

Prospective studies are necessary but based on current data optimization of FFR after PCI may result in improved outcomes.