Coronary stenting: the appropriate use of
FFR
Morton J. Kern, MD
Professor of Medicine
Chief of Cardiology LBVA
Associate Chief Cardiology
University California Irvine
Orange, California
To treat or not to treat?
Is this lesion producing Ischemia?
Is PCI appropriate for situation?
The rationale for using coronary physiology is the inability of
the 2D images of angiogram to accurately depict the 3D
lesion characteristics limiting flow.
75% Dia
20% Dia
Uncertainty in Critical
Angiographic Based Decisions
• Intermediate Stenosis, no evidence
ischemia
• Left Main Stenosis
• Multivessel CAD
• Serial Lesions
• Ostial and Branch Disease
Measurement of FFR correlates to the
results of stress testing and ischemia out
of the lab.
FFR is a ‘stress test’ for that artery in
the lab at time of cath.
Aortic, Pa
FFR= Pd/Pa = 65/90 = 0.72
Coronary, Pd
Resting pressures
Adenosine
5 Steps to Accurate FFR
1. Zero guide and wire on table to atmosphere
2. Insert wire into guide and match wire/guide
pressures in aorta
3. Cross lesion 2-3cm distal
4. Turn on IV adenosine 2-4 minutes
5. Confirm accuracy with pressure pull back
Rely on FFR
Avoid pitfalls of pressure and FFR
Hemodynamic Artifacts:
• Damped pressure
waveforms.
• Guide obstruction
• Contrast media
• Very small guide (<5F)
• Pressure signal drift
• Side holes and ostial
‘pseudostenosis’
Technical
• loose connections
• Improper zero
• Calibration offset
Anatomic
• Extreme tortuosity
• Inability to wire vessel
• Spasm
Mechanical
Wire/artery impact
Pharmacologic
• Inadequate hyperemia
Rely on FFR
Effect of Wire Introducer
Rely on FFR – No Guide Catheter Side Holes or
Damping
From Nico Pijls
Rely on FFR – Avoid Signal Drift
Drift
Drift
True Gradient
Notch
Notch
No notch
Notch
Severe stenosis filters high
frequency components – No
dichrotic notch
Notch
No notch
Distal wave form is one key to drift
IV vs IC Pharmacologic Hyperemic agents
Q: Why can we not use IVUS/OCT for functional assessment?
A: A single cross-sectional area does not mean the same thing
everywhere.
5
< 4 mm² =
significant stenosis ?
Ref
Diam
(mm)
4
3
2
50
25
% Stenosis for an
Cross Sectional Area of 4 mm²
0
Single anatomic parameters do
not predict FFR with confidence
IVUS v FFR
When can you NOT rely on FFR?
False Negative FFR
1.
Pressure Damping
2.
No hyperemia - wrong drug, not mixed
not delivered (IV?) or side holes
3. STEMI, culprit. STEMI – non-culprit OK
4. LM + LAD when FFRepicardial <0.6
5. Serial lesion FFR of individual lesion (only gradient
useful)
False Positive FFR
1. Technical errors (Pressure signal drift,zero, etc.)
Coronary Physiologic (FFR) Criteria and Clinical
Outcome Studies
Application
FFR
Ischemia detection, >15 studies
Pos <0.75
Neg >0.80
Deferred angioplasty, >8 studies
(Key Study: Defer)
>0.75
Multivessel FFR guided PCI, LM,
Ostial, Jailed Side Branch
>0.80
(Key Study: FAME I, II)
(Key Study: Hamilos for LM)
(Key Study: Koo BW et al)
Endpoint of stenting
*(IVUS better post stent)
>0.94*
62 yo Man, RCA stent occl 2yr ago with return of CP
LAD FFR=0.86, 0.87
Now 1V CAD and
new approach
DEFER Study – 5 year data
JACC
RW. 59 yo man with Angina, inferior perf defect
3V CAD – CABG vs PCI?
FFR=0.71
2 Questions
How Accurate is Stress Test?
If PCI needed, FFR directed?
JACC 2010;56:177
FAME study: Death and MI after 2 Years
Tonino et al, NEJM 2009, Pijls et al, JACC 2010
Angio-guided
FFR-guided
%
10
12.7
P= 0.03
P= 0.03
8.4
9.5
6.1
5
Death or MI
0
2 year
MI
2 year(exclusion of small
periprocedural infarction)
Fearon WF et al. Circ
2010;122:25450-2550
Cost
Incremental
Increm. Cost
[$] [$]
Economic Evaluation of
FFR-guided PCI in pts with
MVD.
5000
3000
2000
ROTO
1000
BMS
-0.100
-0.075
-0.050
Balloon
-0.025
CABG
-1000
-3000
-4000
-5000
-6000
FFR Guidance
Improves Outcomes
FFR Guidance Improves outcomes
DES
0
0.000
-2000
FFR Guidance
FFR Guidance
Saves
Saves Resources
Resources
ICER of 50,000 $ / QALY
4000
0.025
0.050
0.075
0.100
Incremental
Increm. QALY
QALY
Angiographic 3- or 2-Vessel Disease does NOT equal Physiologic 3- or 2V CAD
FAME: Angiography vs FFR
Tonino, P. A. L. et al. J Am Coll Cardiol 2010;55:2816-2821
3V CAD Angio = 14% physiol
2V CAD Angio= 43% physiol
FAME II – Ischemia directed
PCI+OMT vs OMT alone
Stable patients scheduled for 1, 2 or 3 vessel DES stenting
FFR in all target lesions
Registry
Randomised Trial
At least 1 stenosis
with FFR ≤ 0.80
When all FFR >0.80
Randomisation 1:1
PCI + OMT
OMT
OMT
50% randomly
assigned to FU
Follow-up after 1, 6 months, 1, 2, 3, 4, and 5 24years
FAME II
Rate of Any Revascularisation
Cumulative incidence (%)
60
RCT:OMT vs. RCT:PCI+OMT = 12.1% vs. 1.7%
50 HR (95% CI): 7.63 (3.24-18.0); logrank p<.0001
40
30
20
10
RCT:PCI+OMT vs. REGISTRY:OMT, p=0.54
0
0
1
3
4
5
6
7
8
9
10
12
10
18
1
10
18
1
10
18
1
8
18
1
Months after randomisation
No. at risk
RCT:OMT only
339
RCT:PCI+OMT
352
REGISTRY:OMT only 131
2
238
256
88
123
144
41
119
141
40
115
140
40
112
139
40
83
114
35
20
25
4
25
71 yo Man with typical angina, pos stress, CAD risk factors
What’s your best approach?
FFR CFX
FFR CFX=0.88
LAD Xience 3.5x18. 2nd LAD lesion? All done?
?
FFR = 0.68
Physiologic Guidance
1. Appropriate need
for Stents
2. Objective info re
ischemia
3. Eliminates operator
uncertainty
Chest pain, No objective
evidence ischemia
Asymptomatic Patients
FFR
FFR
FFR
FFR
FFR
FFR
FFR
FFR
FFR
FFR
FFR
FFR
FFR
Revascularization Approaches per AUC
2v CAD with prox LAD
3v CAD
Isolated LM
LM and other CAD
FFR reduces uncertainty and documents appropriateness
The Mandate for Physiologic Guidance arises from
a decade of outcomes studies and is supported by
guidelines
Class IA Guidelines - ESC
Class IIa Guidelines - ACC/ AHA/ SCAI