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Proven outcomes.2,3
Superior value.2,4

iFR is the gold standard among resting indices, backed by patient outcomes showing reduced costs, procedural time and patient discomfort1,4 while providing advance guidance with co-registration.

Learn about the latest iFR studies: DEFINE PCI

View the latest 5-year study outcomes update: iFR Swedeheart Outcomes of a Randomized Trial

iFR is recognized in key cardiovascular societies

  • Only iFR has been designated as “definitely beneficial” by SCAI (Society of Cardiac Angiography and Interventions).5
  • Only iFR has received a Class 1A ESC (European Society of Cardiology) guideline.1


Unseen focal lesions cause residual ischemia

The DEFINE PCI study used iFRpullback to understand the rate and causes of residual ischemia in 500 patients undergoing contemporary PCI. Early results find that residual ischemia is common, and causes are treatable.6-7


Understand ischemia as mapped by iFR pullback and its implications for procedural improvement.

Trial design

  • Primary endpoint: rate of residual ischemia (iFR<0.90) after angiographically successful PCI (residual DS < 50% in any treated lesion)
  • Multi-center, prospective study in 22 US and 6 international centers

  • N=500 patients with CAD and iFR < 0.90 in at least 1 coronary artery with tandem, diffuse, or multi-vessel intermediate lesions
  • Blinded iFR pullback to assess inschemia after PCI
  • 1 year patient follow-up


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1 in 4 patients with angiographically successful PCI left the cath lab with residual ischemia.6

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68% relative reduction in clinical events at 1 yr. follow-up among patients achieving post-PCI iFR ≥ 0.95 (p-value=0.04).7

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Of the patients with residual ischemia, 81.6% were caused by an untreated angiographically inapparent physiologically focal stenosis (≤ 15 mm).6

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The final picture is often incomplete. iFR Coregistration uncovers focal ischemia producing lesions missed visually.

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1-year outcomes DEFINE PCI

-Dr. Allen Jeremias

Hidden lesions video thumb

Help identify hidden lesions DEFINE PCI

-Dr. Zaid Ali

Define GPS study thumb

DEFINE PCI 1-year key findings

-Dr. Gregg Stone

Define GPS thumb

DEFINE PCI signal post PCI measurement

-Dr. Andrew Sharp

Define PCI thumb

Follow up study -DEFINE GPS overview

-Dr. Manesh Patel

Role of physiologic guidance video

Role of physiologic guidance

-Dr. Allen Jeremias

0.89 dichotomous cut-point, backed by clinical outcomes data8  

Both DEFINE FLAIR and iFR Swedeheart used a dichotomous 0.89 cut-point in their protocols to assess patient outcomes. Physicians can feel confident in simplifying their clinical decision-making strategy.

iFR cut point

Proven outcomes

DEFINE FLAIR and iFR Swedeheart

The largest physiology clinical outcome studies

More than 4500 patients, 2 prospective randomized controlled trials, published in the prestigious The New England Journal of Medicine.

Learn more DEFINE FLAIRiFR Swedeheart.

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Consistent patient outcomes using iFR guided strategy, as with FFR


One year outcome results

p <0.001*

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iFR Swedeheart

Five year outcome results⁹

(HR 1.09; 95% CI: 0.90, 1.33)** 

iFR 5 year data

* p-values are for non-inferiority of an iFR-guided strategy versus an FFR-guided strategy with respect to 1-year MACE rates; pre-specified non-inferiority margins were 3.4% and 3.2% in DEFINE FLAIR and iFR Swedeheart, respectively.

**MACE rates at 5-years: 21.5% iFR vs. 19.9% FFR (HR 1.09; 95% CI: 0.90, 1.33)

Superior value

Reduced costs per patient4

DEFINE FLAIR and iFR Swedeheart found that on average, compared to FFR, iFR resulted in:

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dollars saved

Less procedural time2

DEFINE FLAIR found that an iFR-guided strategy resulted in:

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reduction in
procedural time

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40.5 minutes (iFR arm)
vs.  45.0 minutes (FFR arm)

Improved care2,3

The two trials further established that an iFR-guided strategy enables a faster procedure while almost completely eliminating severe patient symptoms compared to an FFR-guided strategy.

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DEFINE FLAIR reported a 90% reduction in patient discomfort.

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iFR Swedeheart reported that with no hyperemic agent, you can achieve a 95.7% reduction in patient discomfort using an iFR-guided strategy.

iFR Co-registration

Decide not just whether to treat, but where to treat with iFR Co-registration


Only Philips co-registers iFR values directly onto the angiogram, allowing you to see precisely which parts of the vessel are causing ischemia, and uses virtual stenting to predict treatment results.

1. 2018 ESC/EACTS Guidelines on myocardial revascularization: The task force on myocardial revascularization of the European society of cardiology (ESC) and European association for cardio-thoracic surgery (EACTS). Eur Heart J. 2018;00:1-96.

2. Davies JE, et al., Use of the Instantaneous Wave-free Ratio or Fractional Flow Reserve in PCI. N Engl J Med. 2017 May 11;376(19):1824-1834.

3. Gotberg M, et al., iFR-SWEDEHEART Investigators. Instantaneous Wave-free Ratio versus Fractional Flow Reserve to Guide PCI. N Engl J Med. 2017;11:1813-1823.

4. Patel M. “Cost-effectiveness of instantaneous wave-Free Ratio (iFR) compared with Fractional Flow Reserve (FFR) to guide coronary revascularization decision making.” Late-breaking Clinical Trial presentation at ACC on March 10, 2018

5. Lofti A, et al. Focused update of expert consensus statement: Use of invasive assessments of coronary physiology and structure: A position statement of the society of cardiac angiography and interventions. Catheter Cardiovasc Interv. 2018;1–12.

6. Jeremias A et al., Blinded Physiological Assessment of Residual Ischemia After Successful Angiographic Percutaneous Coronary Intervention: The DEFINE PCI Study. JACC Cardiovasc Interv. 2019 Oct 28;12(20):1991-2001

7. Patel M et al. The DEFINE PCI Trial: Blinded Physiological Assessment of Residual Ischemia after Successful Angiographic Percutaneous Coronary Intervention, 1 year follow-up presented at TCT Connect 2020.

8. FDA 510k (#K173860). The iFR modality is intended to be used in conjunction with currently marketed Philips pressure wires. In the coronary anatomy, the iFR modality has a diagnostic cut-point of 0.89 which represents an ischemic threshold and can reliably guide revascularization decisions during diagnostic catheterization procedure.

9. Gotberg M. et al. iFR-SWEDEHEART: Five-Year Outcomes of a Randomized Trial of iFR-Guided vs. FFR-Guided PCI. Late-breaking clinical Trial presentation at TCT on November 4, 2021.

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