coronary pressure measurent and fractional flow reserve jan willem bech, md, phd coronary pressure...
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CORONARY PRESSURE MEASURENT AND FRACTIONAL FLOW RESERVE
Jan Willem Bech, MD, PhD
Coronary pressure measurement and Fractional Flow Reserve in special situations.
Edinburgh, october 25th, 2002
Aorta coronaryartery
Myocardium
100 0
Normal perfusion pressure
Pa
100 Pd0
Stenotic perfusion pressure
Pa
Qnormal
Qstenosis
Qstenosis Stenotic perfusion press. Pd
FFR = = = Qnormal Normal perfusion press. Pa
Max. hyperemia
Pd
Characteristics of FFR
• FFR is not influenced by changes in blood pressure, heart rate, or contractility
• FFR has a unique normal value of 1.0 in every patient and every coronary artery
• FFR incorporates the contribution of collateral flow to myocardial perfusion
FFR threshold for ischemia
FFR
Noischemia
Yes ischemia
1.00 0.75 0.00
FFR < 0.75 inducible ischemia (spec. 100 % )FFR > 0.75 no inducible ischemia (sens. 90 % )
Pijls, De Bruyne et al, NEJM 1996
FFR < 0.75 ischaemia inducible: revascularization is justified.
FFR > 0.75 ischaemia highly unlikely: ? is it justified to DEFER revascularization, even
when the lesion is angiographically serious?
DEFER STUDY: 325 pat. all accepted for elective PTCA of a single lesion.
Just prior to PTCA FFR was determined.
Decision making based on FFR 0.75
Bech et al, Circulation 2001
DEFER study
325 patients144 patients FFR
< 0.75 => Ischaemia
PTCA 144 patients
181 patients FFR > 0.75 => No ischaemia
Randomisation
Performance of PTCA 90
patients
Deferral of PTCA 91 patients
Bech et al, Circulation 2001
2 yr follow-up2 yr follow-up
DEFER 2 jaar follow-up: event-free survival
Bech et al, Circulation 2001
0 6 12 18 2450
60
70
80
90
100
FFR 0.75. Geen PTCA
FFR 0.75. Wel PTCA
83%
89%
Maanden
Pe
rce
nta
ge
pati
en
ten
vri
j v
an
ev
en
ts
No PTCA
PTCA
The DEFER Study: Conclusion
In patients admitted for PTCA of a single lesion, but with a FFR more than 0.75 just prior to PTCA, deferral of revascularization is at least as good as performance of an intervention.
Although these patients have angiographic CAD and are at increased risk for events as compared to the general population we can conclude that performance of an intervention does not reduce this risk.
FFR to evaluate PTCA
FFR after coronary intervention should preferably be higher than 0.90
POBA: Follow-up 2 years: FFR < 0.90 event rate 41 % FFR > 0.90 event rate 15 % (Bech et al, Circulation 1999)
Multicenter registry Europe-USA-Asia750 pat. post-STENT FFR
0.96-1.000.86-0.90 0.91-0.950.81-0.850.76-0.800%
10%
20%
30%
40%
% death, infarction, or re-intervention at 6 mnths.
4%
7%
19%
28%
37%
Post-STENT FFR
After stenting: Inverse correlation between FFR and event rate.
How does FFR works in complex coronary
disease?
• difficult anatomy, poorly visible lesions, overlap
• multiple stenoses within one artery
• diffuse disease
• left main disease
• multivessel disease
CORONARY PRESSURE MEASUREMENT
LAD D 1D 2
Male, 67, stable angina, positive exercise test
RCA
LCX
2 intermediate stenoses mid RCA Complex lesion proximal LAD
0
100
FFR = 92/98 = 0.94
Pa
Pd
Pa
Pd
LAD, hyperemia
FFR = 87/97 = 0.890
100
Pa
Pd
Pa
Pd
DIAG 2, hyperemia
FFR = 87/96 = 0.900
100
Pa
Pd
Pa
Pd
DIAG 1, hyperemia
0
100Pa
PdFFR = 38/92 = 0.41
RCA, hyperemia
Balloon 3.0 mm
FFR = 55/82 = 0.67
100
0
Pa
Pd
After balloon inflation3.0 balloon 12 atm
Stent 3.5 mm(mid-RCA)
Stent 3.5 mm(mid-RCA)
FFR = 76/95 = 0.80
100
0
Pa
Pd
Pull back pressure wire
Pressure drop
Additional Stent 3.5 mm (prox-RCA)
Stent 3.5 mm(mid-RCA) +Stent 3.5 mm(prox-RCA)
FFR = 88/94 = 0.94
100
0
Pa
Pd
Pressure Wire:Use during complex interventions
In this patient with complex coronary artery disease,coronary pressure measurement:
• confirmed the appropriateness of stenting the RCA while avoiding a riskful intervention of the LAD or bypass surgery
• Selected the correct spots in the RCA where to stent
• evaluated the result of stenting.
How does FFR works in complex
coronary disease?
• difficult anatomy, poorly visible lesions, overlap
• multiple stenoses within one artery
• diffuse disease
• left main disease
• multi vessel disease
CORONARY PRESSURE MEASUREMENT
AB
Coronary Pressure & FFR: Pull-Back Curve
Focal disease: sudden changes in pressure
Coronary Pressure & FFR: Pull-Back Curve
Diffuse coronary disease: gradual increase of pressure.
• By slowly retrieving the pressure wire under fluoroscopy and sustained hyperemia
• the individual contribution of every segment of the coronary system to the extent of disease can be studied and such spatial information cannot be obtained by any other method
FFR: The Pressure Pull-back Curve
How does FFR works in complex coronary
disease?
• difficult anatomy, poorly visible lesions, overlap
• multiple stenoses within one artery
• diffuse disease
• long and ostial lesions
• left main disease
• multivessel disease
CORONARY PRESSURE MEASUREMENT
Decision making in equivocal left main coronary artery
disease by Fractional Flow Reserve
Bech et al, Heart 2001
Background
•The presence of angiographic clearly significant LMCA stenosis is often decisive in the choice for surgical treatment.
•However, often patients are encountered with angiographically an intermediate LMCA stenosis of unclear physiological significance.
•It is unclear whether bypass surgery should be performed.
Aim of the study
•To investigate the usefulness of pressure derived FFRto decide between medical versus surgical therapy in patients with equivocal LMCA disease.
Events during follow-up54 patients
FFR > 0.75N=24
Medical Group
FFR < 0.75N=30
Surgical Group
Mean follow-up (mths) 28 15 2914
Death 0 1
MI 0 1
Early re-operation -- 3
CABG 3 0
PTCA 2 0
Total 5 (21%) 5 (17%)
Conclusion
•FFR is useful in equivocal left main coronary artery disease.
•If LM FFR 0.75, a conservative medical of the LM lesion approach seems to be safe.
•If LM FFR < 0.75, the stenosis bears physiologic significance which justifies bypass surgery of the LM lesion.
How does FFR works in complex coronary
disease?
• difficult anatomy, poorly visible lesions, overlap
• multiple stenoses within one artery
• diffuse disease
• long and ostial lesions
• left main disease
• multivessel disease (submitted for publication)
CORONARY PRESSURE MEASUREMENT
Background 1
In multi-vessel disease,
• The most important prognostic index to predict outcome is the extent and severity of inducible ischemia.
• It has been demonstrated that from a symptomatic and prognostic point of view revascularization is indicated only for functionally significant (culprit) stenoses.
• In order to choose the optimum treatment, it is of paramount importance to know which of the angiographic stenoses are culprit and which are not.
• In multi-vessel disease, non-invasive testing can often not indicate which lesions are culprit.
• Fractional Flow Reserve can assess if a specific stenosis or segment is culprit or not by the ischemic threshold value of 0.75.
Background 2
• Not to answer the question whether CABG or PCI is a better treatment in all patients with multivessel disease
• But to investigate which is the optimum treatment in an individual patient with multivessel disease.
• CABG for a patient with a large area at risk versus PCI for a patient with a limited area at risk.
Aim
Inclusion
• Patients with angiographically MVD
• Technically suitable for CABG or PCI
Procedure
• Multivessel coronary pressure measurement by the so called “pull-back procedure” was performed.
• A coronary artery was defined as culprit when FFR < 0.75.
• If 3 or 2 (including LAD) culprit arteries CABG was performed.
• If 1 or 2 (excluding LAD) culprit arteries PCI was performed.
Conclusion
In multi-vessel disease, coronary pressure measurement is an excellent tool to identify the culprit lesion(s) by FFR < 0.75 and facilitates the choice for the optimum treatment modality (CABG or PCI)