1. Physiological Assessment of Left Main Coronary Artery Disease
Bhavik Modi*,Tim van de Hoef#, Jan Piek# and Divaka Perera*.
EuroIntervention. June doi: /EIJ-D
* St Thomas’ Hospital Campus, King’s College London
# AMC Amsterdam, Netherlands

2. WHY LEFT MAIN? LMCA disease found in 5-8% of angiograms
LMCA supplies on average 75% of myocardium
LMCA medically managed (CASS registry 70’s) = 50% mortality at 3 years!
LMCA revascularization is an area of ongoing diagnostic and strategy dilemma – NOBLE / EXCEL

3. EVIDENCE?
Evidence Supporting Physiology-guided management in the Catheter Laboratory has been growing.You will all know:
DEFER, FAME, FAME2
RIPCORD
DEFINE-FLAIR But did you know:
None include LMCA
Original validation study of FFR vs basket of non-invasive tests included only 2 patients with LMCA disease
This is despite LMCA misclassification of upto 50% using angiography alone

4. 51 consecutive intermediate LMS lesions (40-80%)
1.00
1.00
0.90
0.90
0.80
0.80
51 consecutive intermediate LMS lesions (40-80%)
0.70
0.70
0.60
0.60
4 interventional cardiologists
0.50
0.50
not significant
significant
unsure
not significant
significant
unsure
Independently graded as Significant, Not Significant or Unsure
1.00
1.00
0.90
0.90
0.80
0.80
Lindstaedt et al 2007
0.70
0.70
0.60
0.60
0.50
0.50
not significant
significant
not significant
significant
unsure

5. OBSERVATIONAL DATA

6. OBSERVATIONAL DATA Is the LMCA different?
consequence of plaque rupture greater
larger proportion of myocardium subtended
Does measuring into LAD vs Cx differ (Yes if downstream resistance to flow)

7. CHALLENGES? ØTechnical considerations
Pressure damping, need to disengage guide
Achieving adequate hyperemia only possible with IV adenosine
ØSerial Disease
Downstream non-contiguous disease in both branches (LAD and LCx)
Disease non-contiguous disease in only one branch. In this case safe to use disease- free side-branch to isolate ‘true’ significance of proximal lesion, especially if LM FFR measured when diseased branch doesn’t have FFR<0.45

8. Be guided by FFR w llback troce
Measure FFR towards both LAD and LCx + + w
LAD AND LCx
F R > 0.80
LAD -OR LCx
FFR S 0.80
LAD AND LCx
FFR S 0.80
Disoordant FFR result
LMCA not significant '
CABG or PCI
Be guided by FFR w llback troce
OMT
LAD LCX
Pa t ie nt s for PCI:
Perf orm FFR p u llback, treat largest step up, repeat pullback unt il FFR > If pullback equiv al ent, be guided by IVUS of LMCA, using MLA as cut -off K
ING'S
College
LONDON
University of London

9. CONCLUSIONS
Considerable evidence base supporting physiology-guided revascularization largely excludes LMCA but with some promising observational data
Challenges exist – technical and serial disease
Using disease-free side-branch to isolate ‘true’ significance is a viable option
We propose an algorithm involving pressure wire pullback from both LAD and LCx when you encounter LMCA disease.Treat biggest step-up and remeasure
Randomized trial data needed