News:FFR-guided PCI Reduces Incidence of Clinical Events in Patients with Multi-Vessel Disease: Results of the FAME Study

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October 15, 2008 by Leah H. Biller [1]

TCT 2008 - Washington DC: Researchers reported that for patients with multi-vessel coronary disease, treatment with fractional flow reserve (FFR) guided percutaneous coronary intervention (PCI) reduced the risk of adverse clinical events when compared with standard angiography- guided PCI. The results of the Fractional Flow Reserve Versus Angiography for Multivessel Evaluation (FAME) study were presented by Nico H.J. Pijls at the Plenary Session 5: Late Breaking Clinical Trials 1 Session of TCT 2008 on Tuesday, October 14, 2008.

FFR, defined as the ratio between the maximum blood flow in a region of stenosis to the normal maximum blood flow, is a lesion-specific measurement of ischemic severity ^[1]. Previous studies have demonstrated the importance of considering the functional effects of epicardial stenoses in addition to anatomical presentation; in fact, researchers determined that it was safe to defer intervening on stenoses with high FFR indices, even those initially deemed significant by traditional angiographic assessment ^[2].

FAME was a multicenter, international, parallel assignment study. 1005 patients with multi-vessel disease (defined as having stenoses >50% in at least two coronary arteries) were randomized to FFR-guided (n= 509) or to angiographic-guided (n=496) PCI. In the former arm, drug-eluting stents were used only when the FFR index was ≤ 0.80. ^[3]. FFR was measured using a Pressure Wire (Certus Wire, RADI Medical Systems). In the angiographic-guided arm, all stenoses >50% were stented ^[4].

Researchers found that FFR-guided PCI had various during-procedure benefits: fewer stents were placed (1.9 in FFR arm vs. 2.7, p <0.001); less contrast was used (272 vs. 302 mL, p< 0.001); material costs were less ($5,332 vs. $6,007, p<0.001); and the duration of hospital stay decreased (3.4 vs 3.7 days, p=0.05) ^[5].

The benefit of FFR-guided PCI extended to clinical events at one year as well, as reported at TCT 2008. The rate of the composite variable of death, myocardial infarction, or repeat PCI was significantly less for patients in the FFR-guided PCI treatment group as compared with the angiography-guided group (13.2% and 18.4% respectively, p=0.02). Significant reductions were also found for the variable of death or MI (7.3% vs 11.1%, p=0.04). ^[6]. This translates to an approximate 35% reduction of the risk of death or MI for patients treated with FFR-guided PCI ^[7]. There was no significant difference between arms at one year in terms of angina or quality of life ^[8].

The findings of the FAME study suggest the potential utility of FFR-guided PCI for patients with multi-vessel disease. FFR indexing enables the interventionalist to place stents specifically in lesions causing significant ischemic effects, regardless of the anatomical presentation of the stenosis. However, according to Dr. Deepak Bhatt at Cardiosource, “further trials are necessary to validate these findings before FFR can be considered for routine use.” Although the FAME investigators were skilled in the use of FFR, “most operators have limited experience” and thus “the benefits and applicability of FFR in routine practice may be diminished as a result of errors and higher complication rates” ^[9].

Nonetheless, the FAME study does add to the body of knowledge concerning how (and what) to treat for patients with coronary disease. The ischemic effect of each lesion is an important metric, and perhaps, as the results of FAME start to suggest, more critical than anatomical meausures of percent stenosis when considering stent placement.

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