Yes. Good lung ventilation is needed to come off cardiopulmonary bypass, which is usually done for 3-vessel cabg. Mild COPD may not be a problem. Severe COPD may have problem, though if this bad, probably can't exert enough to benefit from cabg. COPD may prolong time to extubation after surgery. You will be carefully evaluated and tested prior to surgery, unless truly emergent.
Yes. Often times, patients presenting for bypass surgery have co-existing COPD as smoking, the most common cause, is also a cardiac risk factor. Certain tests may be performed on a patient with such to determine his "surgical risk" with the copd. With that information, an informed decision may be made as to whether surgery is the best option.