Fractional flow reserve (FFR) is a technique that evaluates the hemodynamic significance of coronary artery stenoses. It is defined as the ratio of maximal flow achievable in the stenotic coronary artery to the maximal flow achievable if the artery was normal. An FFR value ≤ 0.80 is considered hemodynamically significant. Several clinical trials including DEFER and FAME have found that FFR-guided revascularization reduces major adverse cardiac events compared to angiography-guided procedures alone by helping to identify which intermediate lesions are functionally significant. Guidelines recommend using FFR to guide revascularization decisions, especially for intermediate lesions, multivessel disease, and acute coronary syndromes.

1. FRACTIONAL FLOW RESERVE
Dr. Priyanka Thakur
DM cardiology Resident

2. • Coronary angiography is the most accurate
morphologic assessment of the lumen of the
epicardial coronary arteries till date, but is
limited in gauging the functional
repercussions of coronary stenoses.

3. LIMITATIONS OF CORONARY
ANGIOGRAPHY
• highly subjective
• provides a 2–dimentional view of a 3-dimensional lumen.
• Severity of a stenotic lesion is reported in comparison to a
normal reference segment .
• lumenography & does not provide information regarding
vessel wall.
• An ecentric stenosis has varying appearance of severity in
different views.

4. FFR (Fractional
flow reserve)

5. Technique to evaluate the hemodynamic relevance
of coronary artery stenoses.
"the ratio of maximal flow achievable in the
stenotic coronary artery to the maximal flow
achievable in the same coronary artery if it was
normal"

10. • Normal value is 1 irrespective of the patient , artery or
vascular bed
• Takes into account collateral blood flow
• Stenosis specific
• FFR value ≤ 0.80 is considered significant stenosis
• Independent of prevailing Systemic haemodynamics like
heart rate , blood pressure & LV contractility
• reproducible since the microvasculature has the capacity to
vasodilate till the same extent repeatedly

11. • Relation between FFR & viable myocardium–
If a stenotic vessel supplies a larger viable
myocardial mass, there will be larger
hyperaemic flow during maximal vasodilation
resulting in a greater gradient between Pd & Pa
& thus , a lower value of FFR.
Therefore , the haemodynamic significance of a
lesion is dependent on its perfusion territory.

13. Technique

15. Clinical Applications
• Intermediate lesions (50 to 80 %)
• Multivessel Coronary Artery Disease
• Left-Main Coronary Artery Disease
• Tandem and bifurcation Lesions
• CABG conduit patency

16. CLINICAL EVIDENCE

17. DEFER- Deferral Versus Performance
of PCI of Non-Ischemia-Producing
Stenoses
Study Name Size
Clinical
Presentation FFR Cutoff Outcomes
DEFER
(2001)
325 patients at
14 medical
centers
Stable chest
pain and an
intermediate
stenosis without
objective
evidence of
ischemia
0.75 No benefit stenting
a non-ischemic
stenosis

19. FAME TRIAL - Fractional Flow
Reserve Versus Angiography for
Multivessel Evaluation
Study Size
Trial
Design
Clinical
Presentation
FFR
Cutoff Outcomes
FAME
study
( 2009)
1,005 patients at
20 medical
centers
Prospective,
randomized
Multivessel
CAD
0.80 Routine
measurement of
FFR in patients
with multivessel
CAD who are
undergoing PCI
with drug-eluting
stent significantly
reduces MACE at 1
year

22. FAME 2 TRIAL

24. • Muller et al. demonstrated good prognostication by
deferring revascularization with a negative FFR for
the long-term clinical outcome of patients with an
angiographically intermediate left anterior
descending coronary artery (LAD).
• In this study, medical treatment of patients with a
hemodynamically nonsignificant stenosis (FFR
≥0.80) in the proximal LAD was associated with an
excellent long-term clinical outcome, with survival
at 5 years, which is similar to a control group
without known CAD

25. FFR in Acute Coronary Syndrome
(ACS)

26. Study name Size
Clinical
Presentation
FFR
Cuto
ff Outcomes
Compare
Acute
2017
885 at 24
centers in
Europe and Asia
Patients with
STEMI and
multivessel
disease who had
undergone
primary PCI of
an infarct-
related coronary
artery
0.80 FFR-guided complete
revascularization of non-
infarct-related arteries in
the acute setting resulted
in lower MACE, driven
by decreased
revascularization

27. Indications and Guidelines for FFR
ACC/AATS/AHA/ASE/ASNC/SCAI/S
CCT/STS 2016 Appropriate Use
Criteria for Coronary
Revascularization in Patients With
Acute Coronary Syndromes:
In the presence of an asymptomatic
intermediate-severity non-culprit
artery stenosis, revascularization was
rated as “appropriate therapy,”
provided that the FFR was ≤0.80.

28. European Society of Cardiology (ESC)
and the European Association for
Cardio-Thoracic Surgery (EACTS)
2014
FFR to identify hemodynamically
relevant lesions in stable patients
when evidence of ischemia is not
available
FFR guided PCI in patients with
multivessel disease

29. ACC/AATS/AHA/ASE/ASNC/SCAI/SC
CT/STS 2017 Appropriate Use Criteria
for Coronary Revascularization in
Patients With Stable Ischemic Heart
Disease:
•Invasive measurements (such as FFR)
may be very helpful in further defining
the need for revascularization and may
substitute for stress test findings.
•FFR ≤0.80 is abnormal and is
consistent with downstream inducible
ischemia.