Postoperative Myocardial infarction can occur because of either technical or patients factors- its incidence is hard to estimate though due to various definitions, but most studies place it between 2 and 10%. New ECG features as Q waves and/or US documented alternation of cardiac wall motions are indicative. Ongoing ischemia might prompt emergency angiography or re-operation. Arrhythmias can also occur, most commonly atrial fibrillation (20-40%) that is treated with correcting electrolyte balance, rate and rhythm control.Various neurological adverse effects can occur after CABG, with total incidence about 1,5% they can manifest as type 1-focal deficits (such as stroke or coma)  or type 2- global ones (such as delirium) . Inflammation caused by CPB, hypoperfusion or cerebral embolism. Cognitive impairment has been reported in up to 80% cases after CABG at discharge and lasting up to 40% for a year. The causes are rather unclear, it seems CPB is not a suspect since even in CABG cases not including CPB (as in Off-Pump CABG), the incidence is the same, whilst PCI has the same incidence of cognitive decline as well.Infections are also a problem of the postoperative period. Sternal would infections (superficial or deep), most commonly caused by Staphylococcus aureus, can add to mortality. Harvesting of two mammary arteries is a risk factor since the perfusion of sternum is significantly impaired. Pneumonia can also occur. Complications from the GI track have been described, most commonly are caused by peri-operative medications.
Then the cannulas and the catheter are placed, cardiopulmonary bypass is commenced (venous deoxygenated blood arriving to the heart is forwarded to the CBP machine to get oxygenated and delivered to aorta to keep rest of the body saturated, and often cooled to 32 - 34 degrees celsius in order to slow down the metabolism and minimize as much as possible the demand for oxygen. A clamp is placed on the Aorta between the cardioplegic catheter and aortic cannula, so the cardioplegic solution that the flow is controlled by the surgeon that clamps Aorta. Within minutes, heart stops beating. Anastomosis (grafting)With the heart still, the tip of the heart is taken out of pericardium, so the native arteries lying in the posterior side of the heart are accessible. Usually, distal anastomosis are constructed first (first to right coronary system, then to the circumflex) and then the sequential anastomosis if necessary. Surgeons check the anastomosis for patency or leaking and if everything is as it should be, surgeons insert the graft within the pericardium, sometimes attached to the cardioplegic catheter. The anastomosis of LIMA to LAD is usually the last one of the distal anastomoses to be constructed, while it is being constructed the rewarming process starts (by the CPB).. After the anastomosis is completed and checked for leaks, the proximal anastomoses of the conduits, if any, are next.