My Friend Just Had Open Heart Surgery To Replace His

My friend just had open heart surgery to replace his aortic artery. He also had a double bypass. The surgery was a little over a week ago. Last night, at home, he was awakened by severe chest pains which today the doctor said was "nighttime Angina". Is that normal after this kind of surgery? I thought angina was one of the things this heart surgery was meant to cure. I think I need to ask this question of a cardiologist.