Question 5 from the first paper of 2000 invites us to "list the theoretical advantages and disadvantages of coronary bypass grafting with and without cardiopulmonary bypass".

The list provided by the college offers information which was up to date in 2000. Subsequently, new information has emerged. The table below is a representation of what the answer to this question might resemble if it were asked in the first paper of 2015.

To paraphrase the college:

Advantages of off-pump CABG:

  • Protection from circuit-related complications:
  • Avoidance of aortic cannulation
  • Avoidance of atrial cannulation
  • Avoidance of the effects of cardioplegia
  • Avoidance  of  risks  of  aortic  cross  clamping
  • Decreased costs (less equipment, less staff)

Disadvantages of off-pump CABG:

  • Potential for  myocardial ischaemia without the  protection of  cold cardioplegia during grafting.
  • Unfavorable operating conditions with a beating heart increasing the risk of anastamotic bleeding, suboptimal revascularisation and myocardial ischaemia

Evidence in support of off-pump CABG:

Outcomes Data for On-Bypass and Off-Bypass Coronary Artery Bypass Grafting
Complication On-pump Off-pump
Mortality (all causes)

1.9%

1.6%

Stroke

2.1%

1.4%

Post-op MI

3.9%

3.4%

(the authors of a meta-analysis in 2012 concluded that off-pump bypass "reduces the incidence of post-operative stroke by 30% and has no notable effect on mortality or myocardial infarction")

The college answer laments the lack of information regarding long term graft patency. A recent meta-analysis has demonstrated that with off-pump grafts, there is an increased risk of graft occlusion with all grafts except LIMA and radial artery grafts.

Additionally, LITFL have this article ("Cardiothoracic Surgery Literature Summaries") where two of the more influential on-vs-off-pump trials are thoroughly dissected.

References

Frederick A. Hensley, Jr., M.D., Donald E. Martin, M.D.,  Glenn P. Gravlee, M.D. A Practical Approach to Cardiac Anaesthesia, 3rd ed. Sibylle A. Ruesch and Jerrold H. Levy. CHAPTER 9. The Postcardiopulmonary Bypass Period: A Systems Approach. 2003 by LIPPINCOTT WILLIAMS & WILKINS

André, Arthur C. St, and Anthony DelRossi. "Hemodynamic management of patients in the first 24 hours after cardiac surgery." Critical care medicine 33.9 (2005): 2082-2093.

Ray Raper's chapter in Oh's manual (pp.285)

Complications in cardiothoracic surgery: avoidance and treatment, Little A.G, Merril W.H. � 2007, 2nd ed. Chapter 4 by Creswell and Karis.

Cardiopulmonary bypass- Principles and Practice, Gravlee G.P. and Davis R.F -2007 (3rd ed.)

UpToDate contains a couple of excellent summary pieces on cardiac and non-cardiac complications of CABG.