Surgeons views, data and evidences on AHA CORONARY ARTERY REVASCULARISATION GUIDELINES

1. SURGEONS PERSPECTIVES
of
2021 ACC/AHA Guidelines for Coronary Artery
Revascularization

4. • They do not reflect our interpretation of the best treatment for patients with
ischemic heart disease.
• 3 areas of concern with the guidelines :
1. Downgrading of coronary artery bypass grafting (CABG) in the treatment of three-
vessel coronary artery disease (CAD)
2. Lack of recognition of the superior long-term benefits of CABG vs PCI in decreasing
repeat re-intervention and post-procedural myocardial infarctions
3. Awarding a Class of Recommendation (COR) I to the radial artery as a CABG conduit.

5. • Is not supported by evidence
• ISCHEMIA (as well as other studies cited in the guidelines) should not be used to decrease the recommendation of
CABG in the treatment of multivessel CAD.
• Did not value earlier randomized trials and observational studies (that were valued in past ACC/AHA guidelines)
• The SYNTAX trial found a 40% higher mortality among patients with triple-vessel disease with PCI compared with
CABG.
• Similar results were found in the Evaluation of XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of
Left Main Revascularization (EXCEL) trial
• FAME 3 trial - 50% better freedom from death
• PCI and CABG are equivalent revascularization strategies?
SYNTAX, EXCEL, and NOBLE-the superiority of CABG over PCI in decreasing repeat reintervention and
postprocedural myocardial infarction.

7. • Radial artery COR is similar to the COR for internal mammary artery grafting and higher
than for bilateral internal mammary artery grafting (2a)
• Recommendation are based on a meta-analysis of six relatively small randomized studies
– suitable for radial artery use: Atleast a 75% stenosis of a circumflex artery with a good
distal vessel or a tighter stenosis of a right coronary artery, also with a good distal
vessel.
– excluded : poor left ventricle or right ventricle function likely to require inotropic
support in the early postoperative period.
• AATS and STS support increased arterial grafting and the radial artery as a bypass conduit.
Its COR is similar to internal mammary artery and higher than bilateral internal mammary
artery grafting, Not appear justified.

8. There can be divergent views regarding the interpretation of the evidence.
Extremely concerned regarding 2 issues:
1. Arbitrarily downgraded coronary artery bypass grafting (CABG) from a class of
recommendation (COR) I to IIb in patients with stable multivessel coronary artery disease.
– No new randomized controlled trials are cited to support this downgrade and to reject
the previously held supporting evidence
– The results may not have been favorable for the CABG subgroup in ISCHEMIA. (not been
published to date)
2. Included only one side of the Heart Team. No surgical association was involved, co-authored
or endorsed these guidelines.

12. • Appreciates the herculean task that the guide- line writing committee has
undertaken
• Acknowledge the advances in pharmacotherapy, from antianginals to disease-
modifying drugs
• Medical treatment being given its rightful place in the current guidelines.
 CABG surgery : well-researched and time-tested modality
 Quality of CABG surgery has also improved over the last 2 decades.
 Adoption of at least one internal mammary artery (IMA), multiple arterial grafts
 Evolved Myocardial protection techniques
 Off-pump and An-aortic techniques

14. • Downgrading CABG from Class 1
• SIHD,TVD,Normal LV function (irrespective of LAD d/s) 2b
• SIHD,TVD,LVEF 35-40% 2a
• Standalone Proximal LAD d/s 2b
Fundamental question—Is the evidence to downgrade the recommendations for CABG
in multivessel and proximal LAD in stable CAD robust enough?

15. • Meta-analysis by Windecker et al. : supports the role of CABG in SIHD.
• Errors on 3 fronts:
1. Over-reliance on ISCHEMIA (International Study of Comparative Health Effectiveness with
Medical and Invasive Approaches) Trial
2. Equating and clubbing CABG and Percutaneous Coronary Intervention (PCI) under
“Revascularization”
3. Unqualified generic use of the term “Multivessel CAD.”

17. Is ISCHEMIA trial the “‘Holy Grail”?
• launched in 2012
• 39.6% of the trial patients had TVD
• 36% had proximal LAD lesions
• more than 40% diabetics with multivessel CAD, CABG was grossly under-utilized—only 26%
of all revascularizations
• Non-blinded trial, not randomized, significant cross-over
• Structured to assess the efficacy of the “initial” approach (Conservative versus Intervention)
for the management of CAD.
• Neither designed, nor powered, to determine whether CABG improved survival.
• Reduction of sample size from 8000 to 5179 leading to reduction of the power of the study
• The choice of PCI vs CABG was left to local heart teams
• Enrolled patients with only mild amount of inducible ischemia

18. • 6 years into the trial in 2018, the primary end- points were reconstituted
1. resuscitated cardiac arrest,
2. hospitalization for unstable angina,
3. hospitalization for heart failure,
• no sensitivity analysis for completeness and type of revascularization.
• limited median follow-up of 3.2 years
• only 40% of patients achieved pre-specified target goals with medical therapy.
• CABG sub-group analysis of the ISCHEMIA trial, which is yet to be published
• The study did demonstrate a trend toward improved survival with multivessel CAD
in the initial invasive strategy group
Is ISCHEMIA trial the “‘Holy Grail”?

20. • EXCEL (XIENCE versus Coronary Artery Bypass Surgery for effectiveness of Left Main Revascularisation)
• NOBLE (Nordic–Baltic–British Left Main Revascularisation Study)
• FREEDOM (Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of
Multivessel Disease)
• Surgical Treatment for Ischemic Heart Failure (STICH) trial, the apparent equivalence of the medical and surgical
arms at 5 years yielded to the increased efficacy of the CABG arm at 10 years
• Survival curve diverges in favor of CABG only beyond 5 year
 RCTs comparing GDMT with revascularization
– Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE)
– Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D)
– Fractional Flow Reserve versus Angiography for Multivessel Evaluation 2 (FAME-2)
BARI 2D trial
• No difference in the PCI stratum as compared to optimum medical treatment (OMT) in all-cause death, cardiac
death, or MI

21. Can “Revascularization” be used as a surrogate for “CABG”?
• “New definition” for “revascularization,” that included both CABG and PCI
• PCI treats only the flow-limiting lesion
• CABG
– Creates a surgical collateral distal to the entire atherosclerosis-prone proximal segment
– Protection from future coronary events
– Technique of “myocardial protection,”
– Left IMA, in addition to superior patency, is associated with a lesser degree of downstream distal
vessel disease progression

22. Can “Revascularization” be used as a surrogate for “CABG”?
• SYNTAX trial (40% higher mortality in triple-vessel disease with PCI compared to CABG and
superiority of latter over PCI in decreasing re-interventions and post-procedural MIs)
• FAME-3(Fractional Flow Reserve versus Angiography for Multivessel Evaluation-3) trial, where 50%
better freedom from death, MI, repeat revascularization, or stroke (hazard ratio, 1.5; 95% confidence
interval, 1.1 to 2.2) was observed in the patients randomized to CABG versus Fractional Flow Reserve
(FFR) guided PCI
• “If CABG did not improve survival over Medical Treatment (MT), how would one explain the survival
benefits of CABG over PCI in the EXCEL trial, without suggesting that PCI causes harm compared to
MT?”

23. • Not quoted a single adequately powered randomized study that has compared CABG alone, and not CABG and
PCI bundled together, with standalone medical management, with a sufficiently long follow-up.
• Meta- analysis by Bangalore et al., which has been used as a supportive document, included 14 RCTs with
14,877 patients, with a mean follow-up of 4.5 years. However, 5 of those 14 studies did not have a single patient
undergoing CABG and the number of patients in the revascularization arm who got a CABG was 16.2%.
• Meta-analysis by Laukkanen et al., consisting of 12 RCTs comparing “revascularization” with medical
management alone, albeit 9 of them not recruiting a single patient under going CABG
• Meta-analysis by Vij A, Kassab K : 4 out of 7 RCTs did not have a single patient undergoing CABG
Overall, in the revascularization arm, only 15% of patients underwent CABG.
This meta-analysis was essentially a comparison of PCI plus medical therapy versus medical therapy
Can “Revascularization” be used as a surrogate for “CABG”?

24. Multivessel CAD versus amount of myocardium in jeopardy
• Juxta-left main proximal LAD, circumflex and an ostial right coronary artery (RCA)
“multivessel disease” is an altogether different ball game from a triple-vessel
disease with distal involvement of the coronary tree, after major branches have
taken off.
• In the latter group, class IIb indication for survival for CABG may have been justified,
but certainly not when proximal segments are involved.
• The amount of myocardium in jeopardy should have been factored in decision-
making in patients with SIHD with multivessel CAD.
• Myocardial jeopardy scores may be cumbersome

25. Proximal LAD
• Proximal LAD, large amount of myocardium at risk
• Weightage for decision-making, almost at par with left main lesions.
• Earlier guidelines :
2-vessel disease with proximal LAD stenosis of >70% : Class1
In single-vessel disease with proximal LAD stenosis : class IIa,
In single-vessel disease with proximal LAD stenosis , extensive ischemia : Class1
• ISCHEMIA trial
63.8% (2 out of 3 patients) in the study did not have a proximal LAD lesion.
23.5% (One in four patients) did not even have an LAD lesion.

26. Proximal LAD
• Robust meta- analysis of RCTs, Yusuf et al : improved survival of CABG in not only multivessel CAD,
but also in those with single- or double-vessel CAD involving significant proximal LAD stenosis
• Duke single-center study, 18,481 patients with significant CAD (>75% stenosis) under- went PCI,
CABG, or medical management alone. Revascularization with PCI or CABG provided a significant
survival advantage compared with medical management alone, even in single-vessel disease.
• New York registry data concluded that in patients with proximal LAD stenosis of at least 70%, survival
with CABG was superior to PCI, irrespective of the number of coronary vessels diseased

27. Lawton, J. S. et al. 2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization. Circulation.
The Heart Team Approach
27
COR LOE RECOMMENDATIONS
1 B-NR
In patients for whom the optimal treatment strategy is unclear, a Heart Team approach that includes
representatives from interventional cardiology, cardiac surgery, and clinical cardiology is recommended to
improve patient outcomes.

28. Multidisciplinary heart-team!
• “Collaborative,” “Multidisciplinary heart-team,” “patient centered care,” and “shared
decision-making”
• 24 cardiologists versus , 9 surgeons in the drafting committee
• AATS allowed only one representative
• STS allowed only one representative
• All other surgeons on the writing committee chosen by ACC/AHA.

29. Thank You