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:
|Mortality (all causes)||
(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.