FFR in Routine Practice Reduces Stenting, Death, MI Rates

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Routine use of fractional flow reserve (FFR) measurements to guide the use of percutaneous coronary intervention (PCI) in clinical practice reduces the number of stents used and improves clinical outcomes, according to a large registry study published online October 2, 2013, in the European Heart Journal.

Researchers led by Seung-Jung Park, MD, PhD, of Asan Medical Center (Seoul, South Korea), looked at 5,097 patients enrolled before (2008-2009) and after (2010-2011) the institution of routine FFR measurement in the ASAN PCI Registry. FFR use rapidly increased over the study period to a rate of 58% at the end of study enrollment.

In 475 patients, stent implantation was deferred after FFR measurement, comprising 37% of patients measured for FFR and 19% of the cohort after the introduction of routine use of FFR. At 1 year, mortality was 1.1%, with 0.7% of deaths from cardiovascular causes. The MI rate was 3.2% and the repeat revascularization rate was 2.8%.

Using 2,178 propensity-matched pairs, multiple clinical outcomes at 1 year, including the composite of death, MI, and repeat revascularization (primary endpoint) as well as the component endpoints, were lower after the introduction of routine FFR measurement. Definite or probable stent thrombosis was also similar at 1 year (table 1).

Table 1. Cumulative Events at 1 Year


Before FFR
(n = 2,178)

After FFR
(n = 2,178)

HR (95% CI)

P Value

Primary Endpoint



0.55 (0.43-0.70)

< 0.001




0.59 (0.42-0.83)


Death or MI



0.66 (0.49-0.90)





0.47 (0.30-0.74)





0.35 (0.21-0.59)

< 0.001

Definite or Probable Stent Thrombosis



0.40 (0.08-2.07)


On multivariable analysis, FFR was identified as an important predictor of the primary endpoint (HR 0.72; 95% CI 0.53-0.98; P = 0.036) as well as of repeat revascularization (HR 0.61; 95% CI 0.37-1.00; P = 0.05). FFR was also an important determinant of number of treated lesions (P < 0.001), number of implanted stents (P < 0.001), and total stent length (P < 0.001).

Fewer Stents, Better Outcomes

The study authors note that FFR’s contribution in lowering risk of death, MI, or repeat revascularization at 1 year was “primarily due to a reduced number of stents used per patients and a subsequent decreased risk of periprocedural MI and repeat revascularization.” Median number of stents implanted was 2 before routine FFR measurement and 1 after routine use (P < 0.001).

Dr. Park and colleagues add that the ultimate quarterly rate of FFR measurement by the end of the study (58%) could actually be criticized as being low considering the test was mandatory. “However,” they point out, “FFR measurement is neither feasible nor necessary in a number of lesions, including tight stenosis or totally occluded lesions, stenosis evaluated by noninvasive functional study, stenosis with extreme vessel tortuosity or calcification, and the stenosis supplying small myocardium.”

In fact, tight stenosis or total occlusion was the most frequent reason for not measuring FFR. No specific reasons were identified for only 3.6% of patients without FFR measurements.

Frequent IVUS May Be Key

The authors note that IVUS was used to assess lesion morphology and to optimize stent implantation in up to 98% of procedures, which may have been an important contributor to the relatively low overall event rate in the study. Regardless, they conclude, “the routine measurement of FFR in daily practice appeared to be associated with less use of stent implantation and improvement in clinical outcomes at 1 year.”

In an e-mail communication with TCTMD, William F. Fearon, MD, of Stanford University Medical Center (Stanford, CA), commented, “The results are as expected with respect to MI and repeat revascularization. One might have expected a higher death rate in both groups with a trend toward a benefit favoring the FFR-guided cohort.”

He added that the patient population is similar to a US CAD cohort, with the main difference being the high rate of IVUS usage, which is not typical in the United States.

Dr. Fearon expressed hope that clinicians are well versed in FFR measurement, noting that its usage has increased dramatically over the past few years. “Likely, there is still room for increased implementation of FFR, particularly in patients with multivessel CAD,” he said.

Overall, “FFR-guided PCI has been shown to improve outcomes and save resources in randomized studies that may have included a more select patient population,” Dr. Fearon said. “This is an important study because it confirms those findings in a real world, consecutive registry of a large number of patients.”


Park S-J, Ahn J-M, Park G-M, et al. Trends in the outcomes of percutaneous coronary intervention with the routine incorporation of fractional flow reserve in real practice. Eur Heart J. 2013;Epub ahead of print.



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  • The study was supported by funds from the CardioVascular Research Foundation (Seoul, South Korea) and the Korea Healthcare Technology Research and Development Project, Ministry of Health and Welfare, South Korea.
  • Dr. Park reports no relevant conflicts of interest.
  • Dr. Fearon reports receiving research support from St. Jude Medical.