What is the survival chance of a woman of 72years old with the disease of degenerative calcific av of heart artery? Does open heart surgery help her?

Generally excellent. It is quite common place for patients over age 65 to undergo aortic valve replacement surgery for calcific degenerative disease with or without coronary bypass. The outcomes are quite good, particularly in the hands of trained surgeons that focus primarily on heart surgery, i.e. Cardiac surgeons. http://goo.gl/kawno.
Almost certainly. Aortic valve calcification and stenosis is common and treated by heart valve replacement with acceptable risk benefit. Consultation with cardiothoracic surgeon. May need coronary angio if not done yet. Sometimes we have to do some bypass grafts at the same operation.