FFR in Treatment of CAD Supported by New PCI Guidelines

December 16, 2009—In the updated guidelines from the American Heart Association (AHA), the American College of Cardiology (ACC), and the Society for Cardiovascular Angiography and Interventions (SCAI), the level of evidence for fractional flow reserve (FFR)-guided treatment, a physiological measure of coronary stenosis, has been upgraded from a grade "B" to an "A" because of new research that was conducted to determine its efficacy. The FAME (FFR Versus Angiography in Multivessel Evaluation) trial demonstrated improved outcomes for patients with multivessel coronary artery disease whose treatment was guided by an FFR measurement system rather than by standard angiography alone.

The ACC, AHA, and SCAI jointly published the 2009 focused updates of the ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction and ACC/AHA/SCAI Guidelines on Percutaneous Coronary Intervention. The guidelines were summarized in the December 3, 2009 edition of Cardiac Interventions Today eNews.

The guidelines now classify FFR as "class IIa with level of evidence A," which indicates that the data are derived from multiple populations and multiple randomized clinical trials or meta-analyses. The updated recommendation for FFR was issued in response to the FAME trial data that demonstrated many patient benefits, including a 34% reduced risk of combined death or myocardial infarction for those whose treatment was guided by FFR technology before coronary stenting rather than angiography alone.

Because data show that having physiological lesion assessment available prior to placement of coronary stents helps physicians better determine which specific lesion or lesions are responsible for a patient’s ischemia (a deficiency of blood supply to the heart caused by blood restriction), the guidelines suggest that FFR can be helpful in optimizing clinical outcomes. The recommendations state that FFR can be useful in assessing whether an intervention in a coronary lesion(s) is necessary as an alternative to noninvasive functional testing and to help assess intermediate stenosis in patients with anginal symptoms.

The FAME study was a randomized, prospective, multicenter trial that enrolled 1,005 patients with multivessel coronary artery disease. The FAME investigators compared outcomes for patients whose treatment was guided by FFR to those whose treatment was guided only by angiography.

On January 15, 2009, Pim A.L. Tonino, MD, et al published the 12-month results in the New England Journal of Medicine (2009;360:213–224). The data demonstrated that instances of major adverse cardiac events (MACE) (including death, myocardial infarction, or repeat revascularization) were reduced by 28% for patients whose treatment was guided by FFR rather than by standard angiography alone.

At the Transcatheter Cardiovascular Therapeutics (TCT) 2009 scientific symposium in San Francisco in September, William F. Fearon, MD, presented the 2-year results from FAME, which demonstrated that patients with multivessel disease experience a significant decrease in MACE if they undergo percutaneous coronary intervention guided by standard angiography plus FFR measurements. The results also showed a reduction in myocardial infarction risk with FFR guidance, as well as a cost reduction of approximately 14%. The TCT presentation was covered in the October 7, 2009 edition of the Cardiac Interventions Today eNews.

St. Jude Medical, Inc. (St. Paul, MN) commended the societies for their recognition of the value of this treatment strategy. St. Jude Medical’s FFR measurement system portfolio includes both the PressureWire Certus and the PressureWire Aeris. The PressureWire Certus was the only FFR measurement system used in the FAME trial; the PressureWire Aeris is a wireless technology that requires no additional equipment or cabling in the cardiac catheterization laboratory.

Volcano Corporation (San Diego, CA) also commended the societies for this update to the guidelines. Volcano's FFR product portfolio includes the PrimeWire, FloWire, ComboWire XT, and three supporting consoles.

"The FAME study provides very compelling evidence that angiographic imaging alone should not be used to triage intermediate lesions," commented John Hodgson, MD, FACC, FSCAI. "The simple fact that similar-appearing angiographic stenoses can be significant 39% of the time and insignificant 61% of the time (in terms of causing or not causing ischemia) highlights the limitations of the angiogram in making these important clinical and economic decisions. How can you rely only on an angiogram to make a decision to stent or not stent if the data suggest that you will be wrong either 39% of the time or 61% of the time?"

"Realizing the limitations of the angiogram is not a huge surprise, but a key question that many physicians want answered is: How often does the FFR get it wrong, and what are the consequences when that occurs?" continued Dr. Hodgson. "One of the most compelling data points for me is that of the 513 lesions in FAME participants that FFR defined as ’nonischemic,’ which were—as a result—not stented, only one of those lesions led to a myocardial infarction after 2 years (only 0.2%). That is remarkable. We must remember that every stent implanted has its own unique and real risk of adverse events—placing these stents is not ’free’ from a patient risk perspective."