Also, the proximal part of a conduit can be anastomosed to the side of another conduit (by a Y or a T anastomose) adding to the versality of options for the architecture of CABG. It is preferred not to harvest too much length of conduits  since it might cause some patients to need re-operation. With CBP (on-pump)
The patient is brought to the operating theatre, intubated and lines (e.g., peripheral IV cannulae; central lines such as internal jugular cannulae) are inserted for drug administration and monitoring. The traditional way of a CABG follows:

HarvestingA sternotomy is made, while conduits are being harvested (either from the arm or the leg). Then LITA (formerly, LIMA) is harvested through the sternotomy. There are two common ways of mobilizing the LITA, the pedicle (i.e., a pedicle consisting of the artery plus surrounding fat and veins) and the skeletonized (i.e., freed of other tissues). Before being divided in its more distal part, heparin is administered to the patient via a peripheral line (for clot prevention). Catheterization and establishment of cardiopulmonary bypass (on-pump)After harvesting, the pericardium is opened and stay sutures are placed to keep it open. Purse string sutures are placed in aorta to prepare the insertions of the aortic cannula and the catheter for cardioplegia (a solution high in potassium that serves to arrest the heart). Another purse string is placed in right atrium for the venous cannula.
Left radial artery and left Gastroepiploic artery can be used as well. Long term patency is influenced by the type of artery used, as well as intrinsic factors of the cardiac arterial circulation.Venous grafts used are mostly great saphenous veins and in some cases lesser saphenous vein. Their patency rate is lower than arteries. Aspirin protects grafts from occlusion; adding clopidogrel does not improve rates. CABG vs PCI
CABG and percutaneous coronary intervention (PCI) are the two modalities the medical community has to revascularize stenotic lesions of the cardiac arteries. Which one is preferable for each patient is still a matter of debate, but it is clear that in the presence of complex lesions,  significant Left Main Disease and in diabetic patients, CABG seems to offer better results to patients than PCI. Strong indications for CABG also include symptomatic patients and in cases where LV function is impaired. History
Pre-CABG
Surgical interventions aiming relieve angina and prevent death in the early 20th century, were either sympatheticectomy (a cut on the sympathetic chain that supplies the heart, with  disappointing and inconsistent results) or pericardial abrasion (with the hope that adhesions would create significant collateral circulation).French Surgeon Alexis Carrel was the first to anastomose a vessel (a branch of carotid artery) to a native artery in the Heart, in a canine model- but because of technical difficulties the operation could not be reproduced. In mid 20th century, revascularization efforts continued.