Despite data to correlate use of fractional flow reserve (FFR) with improved long-term outcomes as well as reductions in both unnecessary stenting and healthcare utilization costs, FFR is underused in the evaluation and treatment of coronary artery disease (CAD).
At our facility, we advocate for appropriate use of FFR to assess the hemodynamic significance of angiographic lesions, especially for intermediate lesions, to determine whether to stent. Consensus guidelines recommend medical therapy for stable ischemic heart disease with an intermediate coronary stenosis (ICS) (40-70 percent diameter stenosis) of unclear significance when FFR is greater than 0.80 (Catheter Cardiovasc Interv 2014;83:509-18).
In the cardiac cath labs at Spectrum Health Frederik Meijer Heart and Vascular Institute, 18 cardiologists perform approximately 4,000 diagnostic and 1,800 interventional procedures annually. We use FFR in approximately 50 percent of patients with ICS, nearly twice the rate of comparable institutions. We employ FFR-guided PCI decision-making for uncertain cases, especially for patients without prior stress testing.
The DEFER and FAME trials have demonstrated the benefit of FFR-guided intervention relative to angiography alone for the management of CAD (J Am Coll Cardiol 2007;49:2105-11; N Engl J Med 2009;360:213-24). FFR removes the ambiguity that arises from discordant angiogram and stress test findings and provides real-time assessment of lesion-specific information that guides clinical decision-making.
FFR distinguishes significant lesions from the non-significant in patients with acute coronary syndrome and in those with multivessel CAD undergoing elective/urgent catheterization (J Am Coll Cardiol 2007;49:2105-11; N Engl J Med 2009;360:213-24). This distinction supports decisions about whether to “fix” coronary lesions. In general, patients receiving drug-eluting stents (DES) are recommended to take dual antiplatelet therapy (DAPT) for one year. DAPT carries an approximate 1-3 percent annual bleeding risk (Circulation 2006;113:156-75). This risk is compounded for elderly patients on chronic anticoagulation. FFR obviates the unnecessary placement of DES, thereby reducing costs (N Engl J Med 2009;360:213-24) and potentially decreasing bleeding risks associated with DAPT.
The direct cost of FFR (approximately $700) is generally less than a cardiac nuclear scan (approximately $1,000) (Circulation 2010;122:2545-2550). For patients, FFR is more convenient than undergoing a post-catheterization nuclear stress to determine the presence or absence of ischemia. Finally, appropriateness increases, potentially avoiding unnecessary stent procedures.
In U.S. cath labs, FFR utilization is growing. Whereas overall use was reported at 6.1 percent in PCI for ICS in 2012 (J Am Coll Cardiol 2012;60:2337-9), more contemporary FFR utilization is estimated to be 20-25 percent in the intermediate lesion population. The Society for Cardiovascular Angiography and Interventions (SCAI) Quality Improvement Toolkit encourages use of FFR in intermediate lesions as a quality initiative that should be tracked.
Fortunately, there is momentum spurring greater use of FFR. A number of quality leadership organizations, including SCAI and the Accreditation for Cardiovascular Excellence (ACE), encourage appropriate use of FFR. A study presented at the SCAI 2013 annual conference found facilities increased their use of FFR assessment in ICS after they earned ACE accreditation (Catheter Cardiovasc Interv 2013;81:S113).
Science supports FFR use for ICS. It is precise, reproducible and cost-effective, all qualities that should continue to drive its utilization.
David Wohns, MD, is director of the cardiac cath labs and interventional cardiology at Spectrum Health Frederik Meijer Heart and Vascular Institute and is an associate clinical professor of medicine at Michigan State University in Grand Rapids.