(NewsUSA) – Usually you hear cautionary tales of heart attacks due to high cholesterol or high blood pressure, but another vascular disease may be sneaking up your legs: critical limb ischemia (CLI).

CLI is the severest stage of peripheral artery disease (PAD) and the leading cause of amputation worldwide. PAD, which results in at least 160,000 amputations each year in the U.S. alone, occurs when blood vessels restrict blood flow in the limbs, most often in the legs.

If PAD is left untreated, CLI develops, and leg tissues literally begin gasping for air. Poor circulation causes leg and foot tissue to die, leading to gangrene, sores that won’t heal and persistently achy feet — a full-on leg attack that ultimately threatens loss of limb.

“If you have PAD and develop significant discomfort in the leg muscles while at rest, you are at increased risk and should get checked by a physician,” says Dr. Emile Mohler, director of vascular medicine at University of Pennsylvania Health System, and spokesperson for the Vascular Disease Foundation.

Here’s what you need to know about CLI, like who is at risk and what to do to protect yourself:

* Just stop smoking. It’s got to sound old by now, but we’ll keep saying it as long as people keep doing it. Smoking doesn’t only increase your risk of cardiovascular disease but PAD and CLI, too.

* Pay attention to the condition of your legs and feet. Are your feet often in pain or numb, especially when elevated? Are your toes slightly blue? Signs of CLI also include shiny, dry skin and thickening toenails.

* CLI is closely associated with advanced age (55 and up), diabetes and, yes, cigarettes. While these categories suffer the most risk, women who smoke face an even greater threat. Doctors believe that women, who tend to have smaller blood vessels already, create a potentially dangerous mix when smoking cigarettes and taking birth control pills at the same time.

* Ischemic rest pain is a common symptom where legs ache and cramp during exercise or movement. Other symptoms include skin ulcers, lesions and a slow pulse in legs and feet.

Many CLI patients remain undiagnosed. Learn more at www.vasculardisease.org.