CABG: A continuing evolution
ABSTRACT
Use of coronary artery bypass grafting (CABG) has had a resurgence, as clinical trial data emerged showing that it remains the standard of care for patients with complex lesions. Debate exists regarding various factors, including endoscopic vs open vein-graft harvesting, single vs bilateral mammary artery grafts, radial artery vs saphenous vein grafts, right internal mammary artery vs radial artery grafts, and on-pump vs off-pump surgery. More recent developments include minimally invasive approaches, robotics, and hybrid revascularization, which are changing the risk-benefit ratio for this patient population.
KEY POINTS
- CABG is considered the standard of care for patients with intermediate or high coronary artery disease burden.
- Traditional CABG performed via median sternotomy with the use of cardiopulmonary bypass is the technical standard for surgical coronary revascularization.
- Suturing the left internal mammary artery directly to the left anterior descending artery is the most effective technique for coronary revascularization.
- Minimally invasive approaches to CABG are safe and effective alternatives in select patient populations.
MINIMALLY INVASIVE CABG
Robotic CABG
This procedure has advantages and disadvantages. The advantages are primarily related to the minimally invasive approach:
- There is no surgeon hand tremor
- It is less invasive
- It provides better cosmetic results
- It is expected to result in less pain, fewer transfusions, fewer complications, and shorter length of hospital stay, although those have not been proven.
Disadvantages include the following:
- Compromised completeness of revascularization—with some “difficult” vessels left unbypassed
- Longer operative times
- Higher cost
- Concern about graft patency with inexperienced surgeons
- Higher-than-expected mortality in some reports.
In 2013, a study of 500 patients treated with robotic totally endoscopic CABG showed that this procedure could be safe and effective, although the best outcomes were achieved in patients with less severe disease requiring fewer bypasses.26 In other words, it is more appropriate for LIMA-to-LAD suturing and less complex anatomy, and it is best performed with cardiopulmonary bypass with the heart arrested.
Hybrid revascularization
This procedure is a combination of minimally invasive CABG (MIDCAB or robotic CABG) to revascularize the LAD and PCI to treat the remaining vessels in multivessel CAD. The CABG and PCI can be concurrent or staged. The hybrid approach has the attraction of being less invasive and uses the technical standard LIMA-to-LAD approach, but it has the obvious limitation of not incorporating additional arterial grafting and the possibility of a compromised technical outcome in less experienced hands.
A collaborative task force from several cardiovascular medical societies developed evidence-based guidelines to address the hybrid coronary revascularization approach. They give it a class IIa recommendation, indicating that it is a reasonable approach to treating patients in whom there are limitations and challenges to traditional CABG. For other patients, they gave it a class IIb recommendation, indicating that it may be reasonable to use as an alternative to multivessel PCI or CABG.27
THE EVOLUTION CONTINUES: CABG VS PCI
As CABG and PCI continue to evolve, surgical approaches to CAD are becoming more sophisticated with the use of more arterial conduits, less invasive surgical approaches, and development of new types of stents for PCI; however, expect the debate to continue regarding which approach to CAD is best. This is not a battle between surgical and nonsurgical specialties. Rather, the goal should be an amicable, collaborative heart-care team. After all, the most important question is, as always, which therapy is best for the individual patient.
