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FFR: Why Isn't Everyone Using It?

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Functional Measurement
Wouldn't it be great if there were an objective measure to judge whether or not revascularizing a coronary artery was going to benefit the patient? Such an evaluation would bolster the decision of whether to perform PCI or surgery or to defer any procedure and go with optimal medical therapy instead. And wouldn't it be odd to learn that such a test exists, but that less than 20% of cases use this technology?

We're speaking about Fractional Flow Reserve (FFR) -- a simple, quick measurement that can be done as part of diagnostic angiography -- and one which will measure the functional significance of a specific lesion or lesions -- i.e., not how severe the blockage looks on the fluoroscopic image, but how severe the restriction of blood flow actually is -- with a number to boot.

The number is 0.80 and in multivessel disease, an artery that measures less than 0.80 is considered ischemia-producing and therefore is a candidate for revascularization.

Jennifer Tremmel, MD

Which Artery to Stent?
Much has been written about the oculo-stenotic reflex where one can look at an angiogram and say, "There's a narrowing. We should open that up." It makes intuitive sense. You have a patient with chest pain. You cath the patient and two narrowings are revealed: one stenosis in the circumflex and a relatively mild one in the LAD. The circ lesion is clearly more narrowed on the angiogram, so you decide to stent that and leave the LAD alone. Sounds intuitive but, as Dr. Jennifer Tremmel recently showed in her presentation on FFR at the CICT Meeting, you would have been wrong...two fold. You would have unnecessarily stented a non-ischemia-producing lesion (the circ) and you would have left the problem LAD untreated.

Further evidence of FFR's benefit was provided by the now well-publicized FAME study, but an most interesting analysis of the FAME data was published last year in JACC. You can read about this analysis in our feature article, "To Stent or Not To Stent: Fractional Flow Reserve (FFR) Trumps Angiography in Diagnosing Blockages up to 90%", but the bottom line was that two-thirds of the lesions measured by angiography to be in the 50-70% range were "not functionally significant" and did not need revascularization. Two-thirds. In fact in the 71-90% range, one out of five lesions was insignificant.

FFR Recognized by Guidelines and Leaders in Cardiology
So with the recent ramping up of cries of over-stenting and inappropriate stenting which have echoed throughout interventional cardiology, one would think that a tool like FFR would be gaining credence. And it has. The 2009 Focused Updates to the ACC/AHA/SCAI Guidelines on PCI increased the "level of evidence" for FFR to an "A" and stated that FFR "can be useful to determine whether PCI of a specific coronary lesion is warranted."

And the following comments were made to Angioplasty.Org by leaders in cardiology, specifically in the context of judging the appropriateness of PCI. Dr. Ralph Brindis, immediate Past President of the American College of Cardiology (ACC) told us:

Ralph Brindis, MD
"My own personal feeling and bias is that FFR is an extremely important tool and that it hopefully will increasingly be utilized in terms of appropriate decision-making related to PCI going forward. And I also predict that, as we come up with different payment models, particularly related to disease-bundling or episodes of care, that it will become even more encouraged at the local hospital level, so that a stent is put in, after a demonstration of ischemia, particularly in intermediate lesions. I will say that within my own institution at Kaiser Permanente, we are finding increasing value in the use of FFR at the time of catheterization for decision-making."

And Dr. Greg Dehmer, Past President of the Society for Cardiovascular Angiography and Interventions (SCAI) stated:

Greg Dehmer, MD

"Guidelines are now getting stronger in their recommendations to use FFR on intermediate severity stenoses or in situations where you don't have an exercise test beforehand.

I think that will only help to make that better as more people use that technology and become very familiar with that technology"

And Dr. William O'Neill, Executive Dean at Miami's Miller School of Medicine and pioneer of angioplasty for the treatment of heart attack:

William O'Neill, MD
"We've known for almost 25 years that visual assessment of angiograms is reproducible and inaccurate. Every angiographer knows you can make a lesion anywhere from 20 to 70%, just by the frame that you pick when you look at an angiogram. The lesson that the interventional community needs to learn is that you have to be really careful about documenting why you are treating moderate severity lesions. And when in doubt, either use IVUS or FFR to make sure that you can prove to people that the lesion is severe enough to be treated.""

So the question remains, if the evidence is clear, if the guidelines have promoted FFR to an "A" level, if leaders in the field feel it's a valuable tool, why isn't it used more than 20% of the time? The answers lie certainly in reimbursement issues. Adding FFR capability to a cath lab, while actually relatively easy, is still an expense. The catheters themselves also add on a charge. But if, in fact, this technology can save significant costs for our healthcare system, shouldn't its use be higher than it currently is?

Not to mention that, as shown by FAME, patient outcomes are improved!

Reported by Burt Cohen, September 27, 2011