Coronary artery bypass grafting (CABG), first introduced in 1968, is now one of the most common surgical procedures and the most common cardiac procedures worldwide. It is estimated that over 800,000 CABG surgeries are performed worldwide each year. The goals of CABG are to reduce mortality, prevent the progress of heart failure and reduce symptoms associated with coronary artery disease. This chapter deals with cardiac critical care issues that pertain to the patient undergoing CABG and potential post-operative complications.
TopTypes Of Conduits Used For Cabg
Patients currently being referred for surgical revascularization are increasingly complex and have a greater burden of co-morbidity and coronary artery disease than in the previous eras of cardiac surgery (Farkouh et al., 2008; Kapur et al., 2010; Mohr et al., 2013; Serruys et al., 2009). Due to the characteristics and long-term patency, the choice of conduits used for coronary artery bypass grafting impacts long-term outcomes, especially with the increasingly complex patient population (Cheng & Slaughter, 2013). Generally, conduits for bypass grafts are taken from one of four areas of the body: saphenous vein grafts (SVG) from the lower limbs, internal mammary arteries (IMA) from the chest wall, radial arteries (RA) from the forearm and infrequently gastroepiploic arteries (GEA) from the abdomen.
Arterial grafts have demonstrated longer patency than veins which translates to better long-term survival, fewer reoperations, a lower rate of myocardial infarction and less recurrent angina compared to vein grafts (Buxton et al., 2009; Cheng & Slaughter, 2013; Desai et al., 2007; Desai, Cohen, Naylor, & Fremes, 2004; Hayward & Buxton, 2007; Loop et al., 1986; Takagi et al., 2014; Weiss, Zhao, Tian, Taggart, & Yan, 2013).
Internal Mammary Artery (IMA): The internal mammary arteries course on the left and right side of the sternum. Unlike vein or radial artery grafts, IMAs are usually not removed from their original position. They often remain connected to their natural site of origin and only one end is separated from the chest wall (in-situ). The distal end is then anastomosed to one of the coronary arteries. The IMAs appear to be inherently “biologically privileged” as a conduit for CABG. They demonstrate resistance to the development of atherosclerosis, a thinner medial layer with less smooth muscle making it less prone to spasm, a more resistant endothelium protecting it against injury during conduit harvest and reduced proliferative response to known mitogens and pulsatile mechanical stretch (Buxton et al., 2009; Cheng & Slaughter, 2013; Tatoulis, Buxton, & Fuller, 2004).