This document discusses coronary artery bypass grafts (CABG), including indications for CABG, types of grafts used, the surgical procedure, complications, and pathology findings. Key indications for CABG include multi-vessel coronary artery disease, left main stenosis over 50%, and proximal left anterior descending artery stenosis over 70%. Common grafts used are the saphenous vein, left internal mammary artery, and right internal mammary artery. Potential complications include hematoma, acute ischemic syndromes, and graft atherosclerosis. The internal mammary artery is superior to the saphenous vein due to properties that make it less prone to atherosclerosis.

1. CORONARY
ARTERY
BYPASS
GRAFTS :
TECHNIQUE
AND
PATHOLOGY
Moderator:
Prof Kim Vaiphei

2. 1894: Assassination of
the French president
Sadi Carnot
Alexis Carrel

3. Triangulation suture
1912

4. John H. Gibbon
Gibbon-IBM heart lung machine,
6 May 1953

5. May 2, 1960 by Dr Robert Goetz

6. Left main coronary artery stenosis >50%
Stenosis of proximal LAD and proximal circumflex >70%
3-vessel disease in asymptomatic patients or those with
mild or stable angina
3-vessel disease with proximal LAD stenosis in patients with
poor left ventricular (LV) function
1- or 2-vessel disease and a large area of viable
myocardium in high-risk area in patients with stable angina
>70% proximal LAD stenosis with either ejection fraction
<50% or demonstrable ischemia on non-invasive testing
Indications for CABG
Hillis LD, Smith PK, Anderson JL, Bittl JA, Bridges CR, Byrne JG, et al. 2011 ACCF/AHA Guideline for
Coronary Artery Bypass Graft Surgery: A Report of the American College of Cardiology
Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2011 Nov 7

8. Saphenous v
Left internal
mammary a
Right internal
mammary a
Radial a
Right
gastroepiploic
a
Inferior
epigastric a
Splenic a
Types of graft

9. Harvesting – Saphenous v
80-90% at 1 year
50% at 10 years

10. Harvesting – Internal mammary a
RIMA
96% at 1 year
90% at 5 years
LIMA
98% at 1 year
90% at 10 years

11. CABG – procedure
Cannulation of
aorta and right
atrium

12. CABG – procedure
Distal anastomosis
completed first

13. CABG – procedure
Proximal
anastomosis to
aorta above aortic
sinus

14. Suture

15. Clips

16. Anastomoses
LIMA
LAD, LCX
RIMA
LAD, RCA
Saphenous v
LAD, LCX, RCA

17. Dissection of Heart : Post CABG
Dissection to be kept to
minimum

18. Dissection of Heart : Post CABG
Lee AH, Gallagher PJ. Post‐mortem examination after cardiac surgery.
Histopathology. 1998 Nov 1;33(5):399-405.

19. Dissection of Heart : Post CABG
Lee AH, Gallagher PJ. Post‐mortem examination after cardiac surgery.
Histopathology. 1998 Nov 1;33(5):399-405.

20. Dissection of Heart : Post CABG
Lee AH, Gallagher PJ. Post‐mortem examination after cardiac surgery.
Histopathology. 1998 Nov 1;33(5):399-405.
Transverse sections at
site of anastomoses and
from graft vessel and
occluded coronary

21. Complications
Hematoma
Acute ischemic
syndrome
Steal Atherosclerosis

22. Kainuma S, Masai T, Yamauchi T, Takeda K, Iwakura K, Ito H, Abe K, Sawa Y.
Chronic expanding intrapericardial hematoma after coronary artery bypass
surgery presenting with congestive heart failure. Annals of thoracic and
cardiovascular surgery. 2008 Feb 1;14(1):52.

23. Mechanical graft damage – cautery, clips, traction
Size mismatch of vessels
Incomplete revascularisation
Narrowing distal to anastomoses
Decreased elasticity
Increased fibrointimal hyperplasia
Steal phenomenon
Hirsch WS, Ledley GS, Kotler MN. Acute ischemic syndromes following
coronary artery bypass graft surgery. Clinical cardiology. 1998 Sep
1;21(9):625-32.

24. Steal – phenomenon
Takach TJ, Reul GJ, Cooley DA, Duncan JM, Livesay JJ, Ott DA, Gregoric ID.
Myocardial thievery: the coronary-subclavian steal syndrome. The Annals of
thoracic surgery. 2006 Jan 31;81(1):386-92.

25. Post graft atherosclerosis
Bernad SI, Totorean AF, Vekas L. Particles deposition induced by the
magnetic field in the coronary bypass graft model. Journal of Magnetism
and Magnetic Materials. 2016 Mar 1;401:269-86.

26. Hyperplasia at sites of turbulence

27. Otsuka F, Yahagi K, Sakakura K, Virmani R. Why is the mammary artery so
special and what protects it from atherosclerosis?. Annals of cardiothoracic
surgery. 2013 Jul;2(4):519.
Fibro-intimal hyperplasia at 1 week post CABG

28. Internal mammary a. is better than saphenous v.
Otsuka F, Yahagi K, Sakakura K, Virmani R. Why is the mammary artery so
special and what protects it from atherosclerosis?. Annals of cardiothoracic
surgery. 2013 Jul;2(4):519.

29. Internal mammary a. is better than saphenous v.
Motwani JG, Topol EJ. Aortocoronary saphenous vein graft disease:
pathogenesis, predisposition, and prevention. Circulation 1998;97:916-31.
IMA Saphenous vein
Anatomic properties
Endothelial fenestrations Few Many
Intercellular (IC) processes Many Few
IC junction permeability Low High
Internal elastic lamina (IEL) Well defined Poorly defined
Heparan sulfate in IEL/media High Low
Dependence on vasa vasorum Minimal High
Valves Absent Present
Size match with grafted native
vessel
Good Poor
Resistance to trauma of harvesting High Low

30. Internal mammary a. is better than saphenous v.
Motwani JG, Topol EJ. Aortocoronary saphenous vein graft disease:
pathogenesis, predisposition, and prevention. Circulation 1998;97:916-31.
IMA Saphenous vein
Physiological properties
Flow reserve High Low
Shear stress High Low
Nitric oxide/prostacyclin production High Low
Vasomotor response to thrombin Relaxation Constriction
Vasoconstrictor sensitivity Low High
Vasodilator sensitivity High Low
Basic fibroblast growth factor
receptors
Few Many (8× IMA)
Lipolysis Rapid Slow
Lipid synthesis Less active More active
Lipid uptake Slow Rapid