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Which is the Best Approach in Left Main Disease?
○ Prof. Dr. Grigore Tinica
DISCLOSURE
The author has no conflict
of interest to disclose with
respect to this
presentation.
BACKGROUND
• Left main coronary artery (LMCA) disease
•the highest-risk lesion subset of ischemic heart disease;
•traditional indication for CABG;
• Significant unprotected left main coronary artery (ULMCA) disease
occurs in 5–7% of patients undergoing coronary angiography;
• Medically treated ULMCA - 3-year mortality rate of 50%;
• Recent trials evidence
• comparable outcomes between PCI and CABG for LMCA disease
• similar rates of mortality
• serious composite outcomes
• a higher rate of stroke with CABG
• a higher rate of repeat revascularization with PCI
Which is the “real-world” management of
unprotected LMCA
Options for treatment of LMCA disease:
• medical therapy
• PCI
• CABG, either off-pump (OPCAB) or on-pump
• Hybrid procedures according to patient’s clinical status or clinician’s
choice for different scenarios.
TREATMENT OF SIGNIFICANT LMCA DISEASE
LMCA disease - an important independent risk factor for
increased mortality and morbidity at all stages of diagnosis
and treatment of CAD.
The surgery goal - complete revascularization in normal conditions; but
any unnecessary attempts to provide complete revascularization which
threatens patient’s life should be avoided.
The Synergy between PCI with TAXUS and Cardiac Surgery (SYNTAX) score includes factors of coronary
angiographic complexity rather than clinical factors.
○ ACCF/AHA guideline suggests that calculation of the SYNTAX and STS (The Society of
Thoracic Surgeons) scores is reasonable in patients with unprotected LM and complex CAD
(Class IIa recommendation, level of evidence; B)
○ SYNTAX trial - the largest, single published study to date, comparing the outcome of PCI
vs. CABG in patients with 3-vessel coronary disease and LMCA disease
○ SYNTAX II score - anatomical and clinical factors (age,
creatinine clearance, LV function, gender, chronic obstructive pulmonary disease, and peripheral
vascular disease) and predicts long-term mortality in patients with complex three-vessel or LMCA
disease
○ STS score - a risk-prediction model, in patients undergoing cardiac surgery,
with a specific model for CABG and combined CABG and valve surgery; can predict in-hospital or
30-day mortality and in-hospital morbidity.
○ ESC/EACTS guidelines on myocardial revascularization suggest STS score for CABG to assess
short-term outcomes for CABG (Class IB recommendation) and SYNTAX score for both CABG and
PCI to assess medium- to long-term (≥1 year) outcomes (Class IB recommendation)
Anatomical assessment and clinical status of the patients are
added for beter evaluation of the risk stratifcation, mainly on the SYNTAX score.
Risk stratification for decision-making in LMCA disease
PCI or CABG?
28 studies, 22,500 patients with SYNTAX score ≤ 32:
• overall risks for all-cause death, cardiac death, stroke are similar between PCI and CABG
• BMS and initial DES → increased risk for MI associated with PCI
• statistically significant difference in rate of MI in favor of CABG in long-term follow-up
• PCI is associated with a remarkably increased risk for revascularization compared with CABG
SYNTAX SCORE ≤ 32 (low
to intermediate) - no
difference in mortality and
stroke rates between stent
and CABG, no difference
between MI and
revascularization rates
between novel generation
DES and CABG
SYNTAX SCORE ≥ 33
(high) - lower mortality
and a lower rate of repeat
revascularization with
CABG compared with PCI
Zhang et al. BMC Medicine (2017) 15:84
Current guideline recommendation - PCI alternative to CABG in patients with low to intermediate anatomic
complexity.
GUIDELINES
ESC guidelines 2010
ESC guidelines 2014
ESC guidelines 2018
PCI IIaB → IB → IA for isolated LM
(Syntax 0-22)
PCI IIbB → IIaB → IIaA for
intemediate LM (Syntax 23-32)
CABG IA → IB →IA for severe LM
(Syntax ≥33)
GUIDELINES
ESC guidelines 2018
No touch technique for proximal
anastomosis!
GOLD STADARD
TOTAL ARTERIAL REVASCULARIZATION....
but not possible everytime....
Is Syntax score enough?
• Revascularization strategies based on the angiographic appearance of LMCAD
stenosis of intermediate severity (between 50% and 70%) may be inappropriate
• Premature CABG for potentially noncritical lesions - unwarranted surgical
risk and harmful to patients (low graft patency rates and up to a 6-fold higher
rate of accelerated obstruction of bypassed native coronary vessels)
High-risk features suggestive of significant LM or equivalent disease:
(1) treadmill score ≤11,
(2) stress-induced sustained ventricular tachyarrhythmia or nonsustained ventricular tachyarrhythmia >
30 seconds or ST-segment elevation,
(3) exercise LV ejection fraction ≤35%,
(4) large reversible anterior perfusion defect (≥10% LV involvement on nuclear perfusion or ≥12.5% LV
involvement on cardiac MRI) or multiple reversible perfusion defects of moderate size,
(5) stress-induced LV dilation or increased lung uptake in the setting of moderate perfusion defect or
large fixed perfusion defect,
(6) echocardiographic wall motion abnormality involving 2 segments developing at a low-dose
dobutamine (≤10 mg/kg per minute) or at a low heart rate (<120 beats per minute)
Intravascular ultrasound (IVUS) - anatomical extent
Fractional flow reserve (FFR) - hemodynamic significance
FFR ROLE
FFR - better tool for assessing the hemodynamically
significance of LM stenosis• poor correlation quantitative coronary angiography - FFR: FAME trial - 35% of the 50–70%
stenoses haemodynamically relevant (FFR ≤0.80) and 80% of the 71–90% stenoses.
• an estimated stenosis >90% predicts haemodynamic relevance with high accuracy (96%).
• FFR-based assessment strategy at the time of angiography - >40% patients with intermediate-
grade lesions reclassified
• angiographically intermediate LM lesions- FFR ≥0.80 revascularization with favorable
long-term outcomes
• FFR limited by the frequent presence of significant downstream stenoses, which may
underestimate or overestimate the hemodynamic significance of the LM lesion
• The 2 largest trials (DEFINE-FLAIR and iFR-SWEDEHEART) - 0.80 accepted FFR threshold for
defining hemodynamically relevant lesions
LM FFR ≤0.80 - CABG is safe
When no FFR - CABG appropriate in 50-70% stenoses?
FFR ROLE
MODERN APPROACH
Algorithm for heart team management of
LMCA disease
CTO, chronic total occlusion; DAPT, dual antiplatelet therapy;
OMT, optimal medical therapy.
Ramadan R, Boden WE, Kinlay S. Management of Left Main
Coronary Artery Disease. J Am Heart Assoc. 2018;7(7):e008151.
Completeness of revascularization –
defined as the total number of distal grafts
divided by the number of affected vessels
Type of surgeryON or OFF PUMP CABG?
• 6 up-to-date recent meta-analyses comparing off-pump and on-pump CABG
Raja SG. Off-pump versus on-pump coronary artery bypass grafting: comparative effectiveness. Comparative Effectiveness Res. 2015:5 73–79.
In-hospital mortality No statistical significant difference
Mid-term mortality Similar overall mid-term survival
Mid-term major cardio- and
cerebrovascular events
No statistical significant difference
Graft patency Increased risk of occlusion of SVGs, no difference in RAG and LIMA occlusion
Repeat revascularization Statistically significant increase in repeat revascularization rates with off-pump
relative to on-pump
Long-term survival Statistically nonsignificant 14% increase in mortality at ≥5 years with off-pump
relative to on-pump CABG
No. of grafts Fewer grafts with OPCAB (2.7 vs. 3)
Completeness of revasc. Lower rate of completeness of revascularization with OPCAB
Type of surgeryON or OFF PUMP CABG?
What about long-term effectiveness?
Conversion rate off- to on-pump- 4.9% to 7.9% in
large trials due to:
• hemodynamic instability (hypotension)
• coronary anatomy (small size or intramuscular
course)
• ischemia
• arrhythmias
Expected mortality:
• 1.4x for elective conversion,
• 1.6x for emergency conversion (visualization
reasons)
• 2.7x for emergency conversion (hemodynamic
instability)!
Comparable early
outcomes,
better late outcomes
with ON-CAB
Gaudino M et al. Off-Pump Coronary
Artery Bypass Grafting: 30 Years of
Debate. Journal of the American Heart
Association. 2018;7:e009934
53% increase in repeat revascularization
rate at one-year follow-up with OFF-CAB
relative to
ON-CAB!
Zhou P. Meta-Analysis of Repeat Revascularization of Off-Pump and On-Pump
Coronary Artery Bypass Surgery. Ann Thorac Surg. 2018;106(2):526-531.
Type of surgeryON or OFF PUMP CABG?
What about long-term effectiveness?
Incomplete
revascularization in
OP-CAB - strong
independent
risk factor for late death
(3% increase at 12 yrs)
Incomplete revascularization partially
explains lower long-term survival with
OP-CAB.Lower number of grafts and distal
anastomoses, lower rate of complete
vascularization with OP-CAB
Gaudino M et al. Off-Pump Coronary Artery Bypass
Grafting: 30 Years of Debate. Journal of the American
Heart Association. 2018;7:e009934
Robertson MW et al. Complete revascularization is compromised in off-
pump coronary artery bypass grafting. Journal of Thoracic and
Cardiovascular Surgery 2013; 145(4):992-998.
Type of surgeryON or OFF PUMP CABG?
What about long-term effectiveness?
Shroyer AL, Grover FL, Hattler B, et al. On-pump versus off-pump
coronary-artery bypass surgery. N Engl J Med 2009; 361: 1827-37.
ROOBY trial – lower graft patency at 1 year with OP-CAB.
Long-term survival by graft patency
MYOCARDIAL PROTECTION
Cardioplegia distribution is not adecvate because of the proximal stenosis =
impaired myocardial protection.
• Retrograde cardioplegia - better distribution, but myocardial cooling and more
complete functional recovery of myocardium distal to coronary artery stenoses, the
presence of veno-venous shunts and thebesian channels means that distribution of
retrograde cardioplegia may not effectively protect the right-RV and posterior septum.
• A combined approach - a better alternative - antegrade blood cardioplegia
maintained with continuous retrograde blood cardioplegia = reduced
postoperative serum troponin I levels and rates of atrial fibrillation, compared with
approaches using solely antegrade cardioplegia.
In lack of severe aortic insufficiency, half or two-thirds of the dose is given
through the antegrade perfusion cannula and the remaining solution is given
through the retrograde cannula.
CONDUIT SELECTIONIBCV IASI EXPERIENCE
Control:
• 64 pts LM or LM equivalent (50.39%)
LAD revascularization:
•61 LIMA-LAD
•1 RIMA-LAD (patent)
•2 SVG-LAD (patent)
6 occluded LIMAs: 1 LM 95%, 2 LAD 90%, 3 LAD 75%
OM revascularization - 51 cases
•RAG 6 cases - 1 occluded (90% CX)
•RIMA 7 cases - all patent
•SVG 38 cases - 7 occluded (18.42%) (4 CX 100%, 3
CX 75 - 80%, 1 LM 60%)
PL revascularization - 5 cases
• 2 SVG,
• 2 RIMA,
• 1 RAG (occluded) - CX 90%.
RI revascularization - 9 cases:
• 5 SVG (3 occluded - 1 LM 40%, 2 LM equivalent no
RI stenosis),
• 3 RAG (2 occluded - LM 50%),
• 1 RIMA.
127 CCTA 10-16 yrs post-CABG
(139.78±36.64 mo) - 64 LM or LM
equivalent (50.39%)
39 isolated LM or LM
equivalent (9.82%)
CABG 2000-2006
397 patients
operated
220 LM or LM equivalent (55.41%)
Revascularization strategy:
• Complete revascularization - 194 cases (88.18%)
• 23 pts. Y (RIMA-LIMA) - 10.45%
• 20 pts. TAR - 9.09%
• 47 pts. RAG - 21.36%
• 36 pts. BIMA - 16.36%
LIMA - the conduit of choice for revascularization of LAD distal to the LMCA lesion.Tatoulis et al. analyzed 8420 patients, 849 with LMCA disease, and did not report adverse sequelae attributable to graft spasm in
patients with LMCA disease who underwent total arterial grafting.
LIMA sensitive to the degree of stenosis - competitive flow when grafted to ≤75% lesions
Should two grafts be used when the disease affects the origin or the body of the left main
coronary artery where no stenosis exists between the major branches?
Yes, both LAD and CX protected - wide separation of the two territories.
• Arterial grafts (RAG, RIMA) - good patency rates when used for OM revascularization.
• SVG not sensitive to stenosis severity (50% occluded SVG - CX occlusion) but occlusion rate >
arterial grafts.
• RA should not be grafted in case of LM equivalent (<50% LM stenosis) or in LM with 50%
stenosis.
Will these grafts compete?
No, revascularization should be balanced by equivalence of the grafts by connecting the grafts as a
Y-graft so that they arise from a single inflow as the LAD and CX do.
All 7 RIMAs used as Y for OM revascularization were patent, 1/6 RAG occlusion (proximal
anastomosis aorta), 7/38 SVG occlusion (high caliber compared to OM).
NO STUDY UP TO DATE CONCERNING CONDUIT SELECTION OR GRAFTING
TECHNIQUE IN LMCA
CONDUIT SELECTIONIBCV IASI EXPERIENCE
LIMA-RIMA Y emulates native LM flow (angle, caliber)
Coronaries 1.5 mm and >1.5 mm
SVG - 43.33% occlusion rate for grafts
anastomosed to 1.5 mm vs. 22.15% for
>1.5 mm target vessels (p=0.001).
Arterial grafts - 30.77% occlusion rate for
grafts anastomosed to 1.5 mm vs.15.03%
for >1.5 mm target vessels (p=0.008).
2.63 occlusion OR for SVGs (p=0.0041) and
2.31 occlusion OR for arterial grafts
(p=0.0001) anastomosed to 1.5 mm target
vessels.
SVGs - no statistical significant difference
between patent (mean stenosis 90.5%) and
occluded grafts (mean stenosis 90.62%)
(p=0.607).
Arterial grafts - significant difference
(p=0.005), target vessel stenosis of 91.22% for
patent and 78.52% for occluded grafts.
AUC - 90% stenosis cut-off value in affirming
graft occlusion - OR of 3.02 for arterial grafts
anastomosed to target vessels with <90%
stenosis (p<0.001).
IBCV IASI EXPERIENCE
Target vessel
RCA calibre
LITA graft with >90% LAD stenosis
IBCV IASI EXPERIENCE
○ mean angle for Y/T anastomoses with both grafts patent - 47.21o vs. 56o
for anastomoses with occlusion of the free arterial graft (RA or RITA).
○ Significant difference between the anastomosis angle of patent versus
occluded grafts (p = 0.015), a smaller angle being registered in case of
patent anastomosis.
Proximal (Y/T ) anastomosis angle
LIMA-RIMA Y anastomosisSchematic representation of the composite coronary artery
bypass grafts (Owida AA et al.)
47.21o
IBCV IASI EXPERIENCEAnastomosis angle in sequential grafting:
□ 48.60o for patent vs. 53.97o for occluded side-to-side anastomoses,
□ 65.12o for patent vs. 90.80o for occluded end-to-side anastomoses, irrespective to graft type.
Anastomosis angle in single end-to-side:□ arterial grafts sensitive to the anastomosis angle with a mean value of 39.46o for patent grafts
and 44.94o for occluded ones (p = 0.034);
□ venous grafts - non-significant difference;
□ AUC - cut-off angle 60o for an occlusion OR of 5.149 for arterial grafts in case of distal
anastomosis angle ≥60o (p<0.001).
Measurement of distal side-
to-side (A), distal end-to-
side (B), and Y (C)
anastomosis angle
B S.E. Wald df Sig. Exp(B) 95% C.I.for
EXP(B)
Lower Upper
Step 1a Angle 1.639 .444 13.630 1 .000 5.149 2.157 12.292
Constant -2.367 .302 61.476 1 .000 .094
a. Variable(s) entered on step 1: paliere unghi.
Prognostic value of distal
anastomosis angle
PERSPECTIVESNambiar et al. in 2018 - minimally invasive off-pump BIMA revascularization:
• 819 patients - left minithoracotomy incision, LIMA-RIMA Y composite conduit
• TAR average 3.1 grafts
• within 30 days mortality rate 0.7%, conversion rate 0.4%
• 12 months evaluation of graft patency (54% of patients) - 0.4% reintervention (PCI)
Low incidence of perioperative and
postoperative complications, including morbidity.
Potential contraindications:
• severe COPD,
• partial pressure of oxygen of less than 60 on room air arterial blood gas,
• moderate to severe renal dysfunction,
• recent myocardial infarction or cerebrovascular accident,
• intermittent AF and moderate mitral regurgitation requiring a maze procedure and mitral repair.
DECISION ALGORITHM
SYNTAX SCORE
>32
CABG
Left dominance
FFR ≤0.80 / severe stenosis in small
vessel
LIMA-LAD + Y RIMA-OM
FFR >0.8 / intermediate stenosis
in large vessel
LIMA-LAD + SVG-OM (competitive flow)
Right dominance
LIMA-LAD
SVG-OM (low runoff)
23-32
Hemodynamic stability, low
LVEF
Hemodynamic instability →
PCI
<22 → PCI
Algorithm for graft selection
in LMCA revascularization
REVASCULARIZATION IN ST-ELEVATION MYOCARDIAL INFARCTION
Hemodynamically stable STEMI → early CABG – non sustained by current guidelines.
NSTEMI patients → severe comorbidities and late diagnosis → higher perioperative risk → decision
carefully weighted.
Need for a randomized controlled study focusing on the questions of
WHO and at WHICH TIME POINT AMI patients considered unsuitable for
PCI should undergo surgery ?
Delay of revascularization → recurrent myocardial infarction withirreversible loss of cardiac function
Increased rate of perioperativecomplications could mitigate any
potential benefits.
20% - 30% of patients with AMI are considered
noneligible for PCI
KEY POINTS
How to decide?
• Young patients with diffuse disease – TAR
• Elderly patients (>80 yrs) – more SVG
• Target vessel degree of stenosis
• Co-morbidities
• Surgeon’s experience
• Operative team (simultaneous harvesting)
• Number of anastomoses
• Type of anastomoses
• Redo CABG
The most significant factor in graft patency
is flawless surgical technique.
CONCLUSIONS• Current guidelines stress the importance of a “heart team”
approach to management of complex coronary disease
including left main disease.
• The gap in treatment effect between PCI and CABG has
progressively diminished, mainly due to more improved
outcomes with PCI. According to the last guideline, PCI is
indicated in mild (I A) and intermediate (IIa A) LMCA, CABG
remaining the treatment of choice in intermediate(I A) and
severe LMCA.(I A)
• OPCAB is associated with similar early mortality and lower
early morbidity rates compared to on-pump CABG.
• On-pump CABG offers better long term results than OPCAB.
• LIMA-RIMA Y anastomosis - best revascularization strategy as
it emulates native LM flow.
• Special attention should be payed to <75% LM lesions – 30-69%
non significant hemodynamic lesion with FFR – risk of graft
occclusion.
Thank you
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TEHNICA IDEALĂ
• lungime suficientă a graftului pentru a nu fi pus în tensiune (complianță
maximă);
• performanță hemodinamică maximă (unghi anastomoză și stres parietal
minim, raport calibru graft/coronară > 5/3, anastomoză la distanță de
leziune, graft arterial, anastomoză LL, aliniere graft la coronară);
• anastomoze facil și rapid de executat;
• adaptări ușor de integrat în tehnica operatorie;
• compatibilitate dintre fluxul prin graft și presiunea arterială din vasul țintă;
• leziune vasculară minimă în cursul intervenției;
• stenoză critică/ocluzie a vasului țintă;
• mai multe anastomoze/teritoriu coronarian pentru a asigura protecția în
caz de ocluzie a unei anastomoze.
