Results of the FAME (Fractional Flow Reserve Versus Angiography for Multi-vessel Evaluation) trial presented recently at the TCT 2008 suggests that routine measurement of fractional flow reserve (FFR) during PCI reduces adverse outcomes in patients with multivessel disease compared to conventional angiography guided angioplasty.

 

Identifying ischaemic lesions in multivessel coronary artery disease is a challenge and non invasive tests are often unreliable. This multi-centre randomised controlled trial, conducted in various US and European centres aimed to determine whether FFR guidance of PCI improves outcomes in these patients.

 

 A total of 1005 patients with multivessel disease in whom a decision was made to stent all stenoses >50%, were randomised to angiography guided or FFR-guided PCI groups.  In the latter group, FFR was measured  for all significant lesions using  a pressure wire and those with FFR ≤0.8 were treated with drug eluting stents and those with FFR >0.8 were not treated. Baseline characteristics were reasonably similar between the two groups. A third of the patients had presented with unstable angina and approximately 27% had undergone previous PCI.

 

 The investigators managed to successfully measure the FFR in 98% of the lesions of which 67% had FFR ≤0.8. This led to a significantly reduced number of stents being deployed in the FFR group (1.9 vs. 2.7, p < 0.001). This also resulted in a significant reduction in the amount of contrast used, cost of materials and length of hospital stay in the FFR arm.

 

 More importantly, the study showed significantly reduced incidence of major adverse cardiac events (MACE) in the FFR guided PCI arm at 1 year (13.2% vs. 18.4%, p = 0.02). The authors claim that the use of FFR to guide intervention by identifying ischaemic lesions lowers the risk of death or MI by approximately 35% compared to the conventional arm. 

 

 The components of the composite end point did not reach statistical significance when considered separately. The incidence of death (1.8% vs. 3.0%, p = 0.19), MI (5.7% vs. 8.7%, p = 0.07), and coronary artery bypass grafting or repeat PCI (6.5% vs. 9.5%, p = 0.08) at 1 year was not significantly different between the two arms. The number of patients who were angina free at 1 year (81% vs. 78%, p = 0.2) and the quality of life measured (p = 0.65) were also similar between the groups.

 

These preliminary results indicate that FFR guided PCI may be superior to routine angiography based PCI, leading the investigators to conclude that FFR should be an integral part of every interventional procedure. Dr Nico Pijls (Catharina Hospital, Eindhoven, the Netherlands), the lead investigator also claims that the study supports the evolving paradigm of "functionally complete revascularisation"- stenting ishaemic lesions and medical treatment of non ischaemic ones. Treating non-ischaemic lesions with stenting may not provide any benefit, but can add extra risk.

 

Other experts claim that larger randomised controlled trials are needed to confirm the FAME findings.  The technology required is also not widely available and is likely to be a factor limiting the adoption of FFR guided PCI as  standard practice.