Why could smoking be harmful after heart bypass?

YES: Yes ! smoking accerates the process of hardening and narrowing of the arteries which is what made the bypass necessary in the first place.

Many reasons: Healing after surgery is markedly impaired by smoking, which constricts the blood vessels that supply us with oxygen and nutrients. Heart bypass is done because of arteriosclerosis, or "hardening of the arteries, " so when you keep smoking, the new vessels in your heart begin the same process of narrowing down until they don't carry blood, resulting in new heart attacks.Also damages lungs&rest of u.

Causes blockages: Smoking increases blockages in the arteries on the heart (as well as the rest of the body). This is at least as true after bypass. Continuing to smoke significantly increases the chance of the grafts failing as well as new blockages and increases the chance you will need another operation.