I'm in my adult health lecture class right now learning about peripheral vascular disease. My instructor just went over the danger of tobacco use when patients have other predisposing factors to obstructions in their blood vessels. Tobacco use causes vasoconstriction (arterial muscles constrict the vessels), increased platelet aggregation (and therefore blood clot formation), increased levels of epinephrine & norepinephrine which cause further vasoconstriction and increased heart rate, and the introduction of carbon monoxide which interferes with oxygenation.
Severe peripheral vascular disease can result in tissue death and may require amputation of the affected extremity (arms and legs). All of that is just background to what the instructor said next:
"Physicians will often tell their patients, 'You can choose cigarettes, or your extremities, but not both.'"
To which I added, "And remember, it’s hard to smoke without hands, so..."