What is critical limb ischemia?

What is critical limb ischemia?

Critical limb ischemia is a severe block in the arteries of the hands, feet or legs. Arteries are blood vessels supplying oxygenated blood. Marked decrease in blood supply causes severe pain and formation of sores in the skin which are difficult to heal. Pain may be severe enough to disturb sleep and may be partially relieved by hanging the leg over the bed. Critical limb ischemia is a severe form of peripheral artery disease known in short as PAD. It needs urgent medical attention.

Risk factors for critical limb ischemia are similar to those for disease of blood vessels elsewhere like the one which causes a heart attack. It is more common in older males and in women after menopause. Those having a family history of peripheral artery disease are more prone for it. Smoking, diabetes, overweight, sedentary lifestyle, high cholesterol and high blood pressure are the other important risk factors.

Initially blocks in blood vessels of the legs manifest as pain while walking, known as claudication. In critical limb ischemia pain and numbness occurs even at rest. The affected leg is usually colder than rest of the body or the opposite limb if that is normal. Skin becomes shiny and smooth and sores may form which are non-healing for a long period. An extreme situation is gangrene, in which either toes or even part of the foot or leg becomes black and composed of dead cells. This is associated with loss of pulse to that region as the blood vessel is blocked. Toe nails may become thickened.

Critical limb ischemia can be prevented by addressing the risk factors mentioned initially, to prevent the occurrence and progression of blocks. Smoking cessation, weight reduction, changing to an active lifestyle, treatment of diabetes, high blood pressure and high cholesterol will go a long way in preventing blocks and their progression. Of course, we can’t do anything about age, gender and poor family history! They are called as non-modifiable risk factors.

Medications used as part of the preventive regime are also useful as treatment. In addition medications which can reduce the formation of blood clots and prompt treatment of infections are needed. But often critical limb ischemia will not respond to medications alone. The block in the blood vessel will have to be mechanically removed. Simplest method is balloon angioplasty in which small tubes with balloons at the tip are used to remove blocks in blood vessels. This may be followed by insertion of tiny metallic spring like material known as stents.

More advanced techniques are laser atherectomy and atherectomy using diamond burr. Atherectomy means removal of fatty plaques in blood vessels. If there is plenty of calcium deposits within the blood vessels, a new technique is intravascular lithotripsy. This technique uses shockwaves which are similar to the ones used to breakdown kidney stones. The procedure is done using specialized balloons attached to small tubes introduced through blood vessels. The device emits sonic pressure waves to crack the calcified material within the blood vessels.

For those not suitable for procedures done through the blood vessels, surgery is the option. Surgery is usually bypassing the block with either a vein from the body or an artificial graft. Some cases may improve by opening the blood vessel and scraping out the fatty deposits which cause the blocks. Some unfortunate ones with severe disease not responding to these measures may end up in amputation. Amputation may range from removal of a toe to part of the foot or very rarely the whole leg. This extreme situation is what we aim at preventing by avoiding risk factors, early recognition and prompt treatment of critical limb ischemia.