Fractional Flow Reserve: Measuring Pressures in the Marketplace

Dr. Andreas Gruentzig

I don’t know how anyone can do these procedures without measuring pressures!

That’s what Andreas Gruentzig, the father of coronary angioplasty, said to me back in 1985. He knew that looking at the angiogram alone was not sufficient for judging the blockage in an artery. Integral to the design of his technological breakthrough, the double-lumen angioplasty balloon, was a feature which allowed him to measure the blood pressure at either end of the arterial blockage. At the start of the procedure, he could quantify how significant the blockage was; when he was done inflating the balloon, he could see the benefit of the dilatation. The post-angiogram might look good, but the pressures sometimes signaled that blood flow through the area was not. So, inflate again. And maybe again. OK, pressure now looks good, we’re done! Pretty simple. Not brain surgery.

A Brief History of Pressure Measurement
Unfortunately Gruentzig’s balloon was limited by the technology of the time. To deal with more complex cases, newer smaller balloons were developed, and they had to ditch the pressure-measurement feature because there simply was no room for the additional lumen. That all changed a decade later with the development of the pressure wire by Radi Systems, now part of St. Jude, and Volcano Corporation’s competing system. Fractional flow reserve (FFR) could now be built into a wire, and these wires soon became so advanced, flexible and torque-able that a cardiologist could use them as the primary guide wire over which balloons, stents, and other devices could be delivered.

Did I say “Back to the Future?”

Well not quite. As logical and crucial as the element of pressure measurement seems, today it is utilized in less than 20% of cases, even though the DEFER, FAME, and FAME 2 studies all have shown that FFR definitively improves outcomes and reduces the costs of PCI. So, why doesn’t everyone use FFR? That was the subject of an article I wrote three years ago. Part of it is a reimbursement issue. In the U.S. guidelines, FFR only has a Class IIa recommendation; in Europe it’s a Ia – the highest! Also hospital administrators need to be convinced of these facts enough to invest in the equipment and expendables (the wires). The limited reimbursements are a disincentive to using FFR, even though total healthcare costs would be lowered with wider utilization. Finally, interventional cardiologists need to be trained on how best to use FFR, and when. And convinced of its importance. As one FFR advocate wrote to us:

“The benefit of FFR should be obvious to all interventionalists by now. If you’re an interventionalist and not using FFR you are practicing old medicine and should consider retooling or retiring.” — Mort Kern, MD, FSCAI, FAHA, FACC, Chief of Cardiology Long Beach VA and Associate Chief Cardiology, UC Irvine School of Medicine.

The FFR Marketplace
Up until now, the FFR market has been a duopoly, split almost evenly between St. Jude Medical and Volcano Corporation. Both companies have pushed this technology in the marketplace, and have sparred in the courtroom with various patent litigation. Both companies have seen their technology integrated into cath lab imaging systems sold by the major imaging providers: GE, Siemens, Philips, etc. St. Jude has combined its FFR and OCT technologies into the ILUMIEN system, and Volcano has developed an entirely new functional measurement system, called iFR, which does not need to use a vasodilator such as adenosine.

While these companies compete with each other, both have expressed upon occasion that the real challenge to increasing their sales and profits is not in gaining share from each other, but from expanding the field of FFR as a whole.

New Kids on the Blockage
Although the Volcano-St. Jude ownership of the FFR field is long-standing, some new smaller device companies are beginning to enter the marketplace. And the technology is slightly different: instead of pressure wires, these newer systems are utilizing fiber-optics. Quebec-based Opsens, Inc. has already filed for FDA and CE Mark approval of their novel fiber-optic-based fractional flow measurement system. Working with Dr. Olivier Bertrand, the company has miniaturized their technology, used in the oil fields of Alberta, to find petroleum deposits deep below the earth’s surface. So if you ask them what’s in their pipeline…well, you get the idea.

ACIST Medical Systems of Minneapolis has also developed a fiber-optic FFR RXi system which gained FDA approval earlier this year. Interestingly, one of the chief engineers on the project was formerly with Opsens. In a development that is no doubt of great interest to St. Jude and Volcano, device giant Medtronic announced in August a co-promotion agreement with ACIST to help commercialize both their FFR and IVUS products.

We’re also told by some of our UK-based colleagues that St. Jude currently is testing a new FFR system in their labs, one that also uses fiber-optics, and also that Boston Scientific is looking at entry into the FFR space.

What’s in a Number?
This is the title of one of my articles on FFR, a subject we’ve been promoting for many years, one which prompted us to create an Intravascular Guidance Center on Angioplasty.Org. The point is that looking at a coronary blockage only via angiography may give a false impression. A blockage that looks significant under fluoroscopy may in fact not be a problem at all when measured via FFR. And vice-versa.I just witnessed a live case in which what was measured as a 40% lesion (intermediate to low) was actually highly ischemic: one that, using angiography alone, might have gone untreated.

Perhaps it’s stretching the metaphor, but a similar situation has been weighing on the FFR field in recent days, one which has little to do with the health of the body, and everything to do with the health of the marketplace. Volcano Corporation has seen a major drop in its stock price, currently trading under $10/share, down 70% from its all time high three years ago. And, since we’re talking about pressure measurement, the company has been under intense pressure from major stockholder groups. The concern, of course, is whether this has any implications for physicians and patients, seeing as Volcano is a major player in the physiologic measurement field.

The founder of one of the major medical device companies once told me that there was little relation between the stock price and the value of a company’s product. In fact, when his firm acquired another large manufacturer, he had the stock tickers removed from their offices, so that the employees would be focused on their work, rather than the market. Whether or not his observation will hold true in terms of Volcano’s future is yet to be determined. Volcano is releasing its Third Quarter results today and hosting a webcast with Q&A from the stock analysts, so it will be interesting to see the outcomes, to say the least.

But improving outcomes is the name of the game: measurement of pressures in arterial narrowings is critical to treating patients with atherosclerosis, to better target therapy, making sure that significant blockages are treated, while those that are not causing problems are safely deferred.

For more information, read our article on Fractional Flow Reserve, and browse through our Intravascular Guidance Center.

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