FAMOUS-NSTEMI: FFR Guidance Reduces Revascularization in NSTEMI

 BARCELONA, Spain—Guiding the initial management of patients with non-ST-segment elevation myocardial infarction (NSTEMI) with fractional flow reserve (FFR) readings lowers the rate of revascularization and increases treatment with medical therapy, with no significant differences in clinical outcomes through 1 year, according to a results of a small randomized trial presented on September 1, 2014, at the European Society of Cardiology Congress and simultaneously published in the European Heart Journal.

“This trial has demonstrated that FFR was feasible in 100% of the patients in whom it was attempted. It was also safe, with guidewire-related dissections in… 2 of the patients,” presenter Colin Berry, MBChB, PhD, of Golden Jubilee National Hospital (Clydebank, Scotland), said at a press conference. “One of the main conclusions of this developmental study is that a larger… trial is needed to further assess the impact of routine FFR-guided management in NSTEMI patients for health outcomes and cost-effectiveness.” 

Methods
The FAMOUS-NSTEMI trial randomized 350 patients referred for invasive management (mean age 62 years; 74% male) to FFR-guided (n = 176) or standard angiography-guided management (n = 174) at 6 UK hospitals from October 2011 to May 2013. All patients had at least 1 risk factor for CAD, and most had a history of angina at rest (92%) and ECG evidence of ischemia (80%). Median time from the index episode of myocardial ischemia to angiography was 3 days.

FFR was measured in both groups using a pressure-sensitive guidewire in all coronary arteries with stenosis ≥ 30% and normal blood flow (all patients had at least 1 such vessel). The results were revealed to the operators in the FFR-guided group but not in the control group. 


Less Revascularization Performed with FFR Guidance

FFR was measured in at least 1 artery in every patient and in 704 of 706 lesions overall; 61.1% yielded a reading ≤ 0.80, indicating a need for PCI or CABG. After the results were disclosed in the FFR-guided group, the treatment plan (revascularization or medical therapy) was changed in 21.6% of patients. 

The percentage of patients treated initially with medical therapy instead of revascularization (primary outcome) was higher in the FFR-guided group (22.7% vs 13.2%; P = .022). That difference was largely maintained after 1 year of follow-up, although it fell shy of statistical significance (21.0% vs 13.2%; P = .054).

Other factors were largely similar between the 2 groups, including procedural characteristics—duration of index procedure, contrast volume, and number, type, and length of stents—and average total in-hospital health care costs. The rate of PCI was 71% in the FFR group and 79.9% in the control group, while rates of CABG were 6.2% and 6.9%, respectively. 

There were no between-group differences in quality of life or clinical outcomes through 1 year, although the rate of MACE (cardiac death, nonfatal MI, or heart failure hospitalization) excluding procedure-related MI tended to be higher in the FFR-guided group and MI related to revascularization tended to be higher in the control group (table 1).

Table 1. Clinical Outcomes at 1 Year

 

FFR-Guided

(n = 176)

Angiography-Guided

(n = 174)

P Value

MACE

8.0%

8.6%

.89

All-Cause Death

2.8%

1.7%

.54

MACE Minus Procedure-Related MI

5.7%

2.9%

.25

Revascularization-Related MI

2.8%

6.3%

.12

 

In addition, among patients who were initially treated medically, MACE through 12 months was 7.5% in the FFR-guided group (n = 3) and 0% in the angiography-guided group (P = .22).

In terms of safety, there were 8 coronary dissections, but only 2 related to the pressure wire. 

Definitive Study Needed

The apparent increase in late spontaneous MACE in the FFR-guided group “[calls] into question the longer-term safety of an FFR-guided change from PCI to medical therapy in culprit arteries,” Dr. Berry and colleagues write, adding, however that there were too few events to make a firm conclusion. “These observations place emphasis on the need for a larger trial with a design that is informed by these results and powered to definitively assess health outcomes and cost-effectiveness.” 

In an editorial accompanying the paper, Bernard De Bruyne, MD, PhD, and Julien Adjedj, both of Cardiovascular Center Aalst (Aalst, Belgium), say “the message of the FAMOUS trial goes beyond the simple ‘less is more.’ The data suggest a pivotal role of the cath lab in ACS, provided the procedure is comprehensive and of good quality: a left ventricular angiogram and left ventricular pressure recordings, a good quality coronary angiogram, and a complete functional analysis of the coronary circulation. This approach provides all the elements for a complete diagnosis, optimal treatment, and thorough risk stratification. Moreover, this one-stop shop renders the noninvasive diagnostic work-up largely obsolete.”

In comments following Dr. Berry’s presentation, Dr. De Bruyne pointed out some strengths of the trial, including the fact that it is the first to evaluate FFR exclusively in ACS, the high percentage of screened patients who were enrolled (41%), and the measurement of FFR in every patient despite inclusion of inexperienced centers. 

But he also highlighted some shortcomings, such as the relatively small sample size, the lack of power for clinical outcomes, and the 3-day interval between the index episode and the initial angiogram, which suggests that the patients were “not that acute” and that the findings cannot be extrapolated to the more acute setting. In addition, he said, it remains uncertain whether FFR can be used in this way in STEMI patients.

 


Sources:
1. Layland J, Oldroyd KG, Curzen N, et al. Fractional flow reserve vs angiography in guiding management to optimize outcomes with non-ST-segment elevation myocardial infarction: the British Heart Foundation FAMOUS-NSTEMI randomized trial.
Eur Heart J. 2014;Epub ahead of print.
2. De Bruyne B, Adjedj J. Fractional flow reserve in acute coronary syndromes [editorial]. Eur Heart J. 2014;Epub ahead of print.

 

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Todd Neale is the Associate News Editor for TCTMD and a Senior Medical Journalist. He got his start in journalism at …

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Disclosures
  • The trial was sponsored by the National Waiting Times Center Board, NHS Scotland and supported by a project grant from the British Heart Foundation. St. Jude Medical provided the pressure wires. Funding to pay the Open Access publication charges for this study was provided by the University of Glasgow.
  • Dr. Berry reports consulting for St. Jude Medical based on a contract with the University of Glasgow and receiving support from the Scottish Funding Council.

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