Left main disease intervention

1. MANAGEMENT OF
LMCA DISEASE
-ROHIT WALSE
SENIOR RESIDENT
DM CARDIOLOGY
SCTIMST

2. SCOPE
• Background
• Anatomy & Histology
• Definition
• Data: Medical vs Revascularisation
: PCI vs CABG
• Adjuvant Methods to assess LMCA stenosis
• Stenting techniques
• Recommendations
• Conclusion

3. BACKGROUND
• First described by James Herrick in 1912 in a patient dying of cardiogenic shock
after acute myocardial infarction (MI)
• Clinically significant LMCA disease has been found in:
- 3 % to 5 % of all patients who undergo coronary angiography for symptomatic
CAD
• Initial results of balloon angioplasty - not favorable ; had a high rate of procedural
complications and early mortality
El-Menyar AA, Al Suwaidi J, Holmes DR, Jr: Left main coronary artery stenosis: state-of-the-art. Curr Probl Cardiol
32:103–193, 2007.
Grüntzig AR, Senning A, Siegenthaler WE. Nonoperative dilatation of coronaryartery
stenosis: percutaneous transluminal coronary angioplasty. N Engl J Med. 1979;301:61-8.

4. ANATOMY
• Arises from left aortic sinus of
Valsalva
• Three anatomic regions:
- Ostium
- Midshaft
- Distal bifurcation
• Bifurcates into LAD & LCX
• Ramus- 30%

5. ANATOMY
• Length of the LMCA is 10.8 mm (±5.2 mm, range 2 to 23 mm)
• Diameter of non diseased left main
- in men is 4.5 ±0.5 mm,
- in women is 3.9 ± 0.4 mm
• The LMCA is responsible for supplying, on average, 75% of the left ventricle

6. HISTOLOGY
• LMCA ostium
- lacks adventitia
- has considerable smooth muscle cells and elastic fibers arranged
perpendicular to & surrounding the ostium
• MC site of stenosis - midportion or distally at the bifurcation
• The pathologic plaque composition –
pathologic intimal thickening  thin-cap fibroatheroma with or without plaque
rupture

8. DEFINITION- SIGNIFICANT LMCA STENOSIS
• Angiographically significant LMCA stenosis is defined as luminal diameter
stenosis ≥ 50%
• The intermediate LMCA stenosis - an FFR below 0.80 is considered the
significant.
• 80% of LMCA disease has one more coronary artery disease

9. LEFT MAIN EQUIVALENT
• >70% Proximal LAD & LCX stenosis

10. PROTECTED LM VS UNPROTECTED LM
• LM lesion with Patent graft
supplying LAD or LCX or collaterals
• LM lesion
• Non functional graft

11. MEDICATION VERSUS REVASCULARIZATION
• Early observational studies
-Medically treated LMCA stenosis : 3-year survival rates of 50%
- 1 yr mortality > 20%
• Controlled trials to compare CABG with medical therapy alone found that CABG
provided a survival benefit in patients with more than 50% LMCA stenosis

12. • In the Veterans
Administration (VA)
Cooperative Study:
• n= 113 patients with
LMCA disease - medical
therapy (n = 53) or bypass
surgery (n = 60)

13. • n= 1492 patients with LMCA
disease

15. • 15-year cumulative
survival estimates -
37% [surgical group]
27% [medical group]

16. PCI VS CABG DATA
REGISTRY
• MAIN COMPARE (2008)
TRIALS
• LEMANS (2008)
• SYNTAX (2013)
• PRECOMBAT (2015)
• EXCEL (2016)
• NOBLE (2016)

17. PCI VERSUS CABG IN LMCA STENOSIS-
REGISTRY DATA

18. MAIN-COMPARE REGISTRY
• Large, multicentre, long term follow-up study
• N= 2240 patients with unprotected LMCA disease –
PCI (BMS 318, DES 784) or CABG (1138) at 12 major cardiac centers in Korea
• At 3 years after propensity matching, the risks of death and the composite of death, Q-
wave MI, or stroke were similar in the PCI and CABG groups, and these results were
consistent when either BMS or DES was compared with concurrent CABG.

19. MAIN-COMPARE REGISTRY
• The rate of TVR was significantly lower in the CABG group than in the PCI group, with
hazard ratios varying by the type of stent
• DES recipients were almost sixfold more likely, and BMS recipients were almost
tenfold more likely, to require revascularization compared with those who underwent
surgery

23. PCI VS CABG FOR LMCA STENOSIS- RCT DATA
Buszman PE, Kiesz SR, Bochenek A, et al: Acute and late outcomes of unprotected left main stenting in
comparison with surgical revascularization. J Am Coll Cardiol 51:538–545, 2008.
TRIAL STRATEGY JOURNAL N RESULTS
LE MANS TRIAL PCI(BMS+DES) vs
CABG
JACC, 2008 PCI-52 VS CABG-
53
1 yr f/u
Primary
endpoint-
absolute change
in LVEF-
significantly
greater in PCI grp
than CABG
grp.(p-0.047)
Secondary
endpoints-
survival &
MACCE were
similar.
JACC, 2016 10 yr f/u Mortality (21.6%
versus 30.2%;
p=0.41)
MACCE (p=0.28)

24. TRIAL STRATEGY JOURNAL N; DURATION RESULTS
SYNTAX
TRIAL
PCI (TAXUS) vs
CABG
CIRCULATION,
2014
357 --PCI VS
348 –CABG
5 yr f/u
-Syntax <33:
Similar MACCE
(p-0.12) &
Mortality (p-
0.53)
-High TVR in PCI
grp.
LANCET, 2019 10 yr f/u -Similar mortality
(27%) -PCI vs
(28%) -CABG
(0·92 [0·69–1·22]
PRECOMBAT
TRIAL
PCI (Sirolimus) vs
CABG
JACC, 2015 PCI -300 vs
CABG-300
5 yr f/u
-Similar MACCE
(p-0.26) &
Mortality(p-0.32)
- High TVR in PCI
grp
CIRCULATION,
2020
10 yr f/u -Similar mortality
(14.5%)- PCI vs
(13.8%) -CABG
1.13 [0.75–1.70])
PCI VS CABG FOR LMCA STENOSIS- RCT DATA

25. TRIAL STRATEGY JOURNAL N; DURATION RESULTS
EXCEL PCI (XIENCE) vs
CABG
NEJM, 2016 1,905 :
PCI- 948
CABG- 957
(SYNTAX score
<33)
3 yr f/u
PCI non inferior
to CABG (P- 0.02)
[P-0.10 forsuperiority]
NEJM, 2019 5 yr f/u No significant
difference
between PCI and
CABG with
respect
to the rate of the
composite
outcome
• MACCE- all-cause mortality, MI (periprocedural & non-procedural) and stroke.

26. • MACCE- all-cause mortality, non-procedural myocardial infarction, any
revascularisation and stroke.
TRIAL STRATEGY JOURNAL N; DURATION RESULTS
NOBLE PCI (biolimus) vs
CABG
LANCET, 2016 1201:
598- PCI and
603- CABG
5 yr estimates
CABG might
provide better
outcomes than
PCI (p=0.0066)
LANCET, 2019 Mean Syntax-
[22.1]
5 yr f/u
CABG superior to
PCI for the
primary
composite
endpoint
(p=0·0002)

27. INTRAVASCULAR ULTRASOUND
Difficulties with Coronary Angiography with LMCA lesions
• Difficult to evaluate the actual size of the LMCA using angiography alone
• Left main trunk is short and lacks a normal segment for comparison
• Contrast in the aortic cusp sometimes obscures the ostium, and “streaming”
of contrast may result in a false impression of luminal narrowing
• Angiography underestimates stenosis severity

28. INTRAVASCULAR ULTRASOUND
• IVUS before stenting provides useful information about the selection of adequately
sized balloons and stents
• Provides information on:
- Negative remodelling
- Reference vessel size and morphologic complexity
- Stent underexpansion
- Incomplete lesion coverage
- Incomplete stent apposition in postinterventional evaluation
• Helpful in determining a treatment strategy and in optimizing the stent procedure

29. • 145 matched pairs of patients who received a DES, the 3-year mortality
IVUS guidance << angiography guidance (4.7% vs. 16.0%, respectively; log-rank
P = .048; HR 0.39)
• Mortality rate started to diverge beyond 1 year after the procedure

30. Conclusion—Elective stenting with IVUS guidance, especially in the placement of drug-
eluting stent, may reduce the long-term mortality rate for unprotected left main coronary
artery stenosis when compared with conventional angiography guidance

31. INTERMEDIATE LM STENOSIS 30-60%
• Metaanalysis: MLA cutoff 5.35mm2 predicted FFR (0.75) with sensitivity & specificity
0.9
• Jasti et al. IVUS MLA 6 mm2 MLD 2.8 mm correlated with FFR 0.75 (sensitivity 0.93,
specificity >0.95)
• Park & Kang : MLA 4.8 mm2 correlated with FFR 0.8
(negative predictive value 75%), 24% of >4.5 still had FFR
<0.8 & 9% had FFR <0.75

32. INTERMEDIATE LM STENOSIS 30-60%
(ESC 2018)

33. OPTIMAL STENT EXPANSION: LMCA
POC = Polygon of confluence
Kang SJ, Ahn JM, Song H, et al: Comprehensive intravascular ultrasound assessment of stent area and its impact on restenosis and
adverse cardiac events in 403 patients with unprotected leftmain disease. Circ Cardiovasc Interv 4:562–569, 2011

36. FRACTIONAL FLOW RESERVE
• FFR >> 0.80 - strong predictor of favorable survival and low event rates in patients
with intermediate LMCA disease
• Useful for the identification of patients in whom deferral of revascularization would
be associated with favorable clinical outcomes
• Survival rates in patients with intermediate LMCA stenosis,
FFR of ≥0.80 treated medically ~ FFR < 0.80 who underwent CABG

38. HEMODYNAMIC SUPPORT
• Patients with normal left ventricular (LV) function are tolerant of global ischemia
during balloon and stent occlusion
• Hemodynamic support [IABP, Impella, Tandem heart] is not routinely recommended
• May benefit high-risk patients:
- low left ventricular ejection fraction (LVEF)
- very calcified stenosis
- concomitant complex distal disease -
thrombus containing LMCA stenosis
[When in doubt, at least secure contralateral femoral access before
starting]

39. STENTING TECHNIQUES- OSTIAL AND SHAFT LESION
• Maintain Coaxial alignment of the guiding catheter -minimizes ostial injury and
ensures proper positioning of the stent
• With coaxial alignment -easy to advance and position the balloon at the target lesion
• After positioning, the guiding catheter can be gently retracted 1 to 2 cm into the aorta
with gentle forward pressure on the balloon catheter

40. STENTING TECHNIQUES- OSTIAL AND SHAFT LESION
• The ostial LMCA lesion is dilated and stented with the guide tip positioned in the aortic
sinus
• The proximal end of the stent is positioned to protrude very slightly outside the ostium
and is expanded against the aortic wall
• After the deployment of the stent, the stented segment is further dilated with high-
pressure balloon inflations to achieve optimal stent cross-sectional area

42. STENTING TECHNIQUES- OSTIAL AND SHAFT LESION
• The balloon inflations- brief (<30 seconds) and multiple (more than three times)
• Aorto-ostial coverage is not mandatory for treatment of disease limited to the shaft
of the LMCA

43. BIFURCATION LESION
• For LMCA bifurcation disease, the single-stent technique provides more favorable
long-term clinical outcomes compared with the two-stent technique
• IVUS provides accurate information about both main and side-branch disease status
and vascular remodeling in LMCA bifurcation lesions
• If a single-stent approach is chosen, there is always the possibility of placing a second
stent on the LCX, if the result is not optimal. This condition is defined as provisional
stenting

45. BIFURCATION LESION
• If the LCX is large (left-dominant system) and at high risk of flow compromise after
crossover stenting (narrow angle and significant ostial stenosis), an initial two-stent
technique is preferred.
• These techniques fall mainly into four broad categories:
 T-stenting
 crush stenting
 culotte stenting
 Simultaneous kissing stenting (SKS)
• Paucity of data- no consensus has been reached as to which two-stent approach might be
better than others.
• Ongoing TRIAL- EBC MAIN

46. BIFURCATION LESION

48. ISR AFTER LEFT MAIN CORONARY ARTERY
DRUG-ELUTING STENTING
 Angiographic restenosis rate after LMCA stenting - 8% to 42% at 2-3 yrs
 MC site- LCX ostium
 Independent predictors of ISR:
 complex stenting with two or more stents in a bifurcation lesion
 the total number of stents
 bifurcation lesions
 Restenotic lesions
Lee JY, Park DW, Kim YH, et al: Incidence, predictors, treatment, and long-term prognosis of
patients with restenosis after drug eluting stent implantation for unprotected left main
coronary artery disease. J Am Coll Cardiol 57:1349–1358, 2011
Kim YH, Park DW, Ahn JM, et al: Everolimus-eluting stent implantation for unprotected left main coronary artery stenosis. The
PRECOMBAT-2 (Premier of Randomized Comparison of Bypass Surgery versus Angioplasty Using Sirolimus-Eluting Stent in
Patients with Left Main Coronary Artery Disease) study. JACC Cardiovasc Interv 5:708–717, 2012.

49. ISR AFTER LEFT MAIN CORONARY
ARTERY DRUG-ELUTING STENTING
• ISR mechanisms- Underexpansion of stents and neointimal hyperplasia
• Real world registry studies reported that most patients with left main ISR were treated
by PCI (drug-eluting stenting or balloon angioplasty), and approximately 10% of patients
received CABG as an initial treatment strategy
• Long-term outcome was favorable regardless of revascularization strategies.
Sheiban I, Sillano D, Biondi-Zoccai G, et al: Incidence and management of restenosis after treatment of
unprotected left main disease with drug-eluting stents 70 restenotic cases from a cohort of 718 patients: FAILS
(Failure in Left Main Study). J Am Coll Cardiol 54:1131–1136, 2009.

51. 2018 ESC/EACTS Guidelines on myocardial revascularization

52. Ramadan Ronnie, Boden William E., Kinlay Scott. Management of Left
Main Coronary Artery Disease. J Am Heart Assoc. 7(7):e008151. 2018

53. CONCLUSION
• Significant left main coronary artery (LMCA) disease should be defined by functional
assessment in addition to angiographic stenosis
• The integrated use of fractional flow reserve (FFR) and intravascular ultrasound (IVUS)
improves outcomes following LMCA stenting
• The use of drug-eluting stents significantly reduces repeat revascularization following LMCA
stenting

54. CONCLUSION
• Circulatory support is not routinely recommended, but should be considered in high risk
patients
• Achieving sufficient minimal stent cross-sectional area after LMCA bifurcation stenting is
important to prevent in-stent restenosis and adverse clinical outcomes
• Outcomes following treatment of LMCA disease with drug-eluting stents are similar to
CABG in patients with low and intermediate lesion complexity

55. • THANK YOU