For most people, peripheral artery disease (PAD) progresses slowly over years. Lifestyle changes, medication, and regular checkups can keep it under control. In some patients, however, PAD crosses a line and becomes critical limb ischemia, or CLI. At that point, we are no longer managing a long-term condition. We are dealing with a limb emergency. In this article, I explain what CLI is, the warning signs to watch for, and how I treat it.
Key Takeaways
- Critical limb ischemia is the most severe stage of PAD, when blood flow is too low to keep tissue healthy even at rest.
- Warning signs include foot pain at night, wounds that will not heal, cold or discolored toes, and weak or missing foot pulses.
- CLI is a limb emergency, so waiting can mean fewer treatment options.
- Minimally invasive procedures such as angioplasty, stenting, and atherectomy can often restore blood flow.
- Quitting smoking, controlling diabetes, and treating PAD early are the best ways to prevent CLI.
What Is Critical Limb Ischemia?
Peripheral arterial disease happens when plaque narrows the arteries that carry blood to the legs and feet. In its early stages, most people feel cramping in their legs when they walk. Doctors call this claudication. The pain eases with rest because resting muscles need less blood. Claudication is frustrating, but it does not usually threaten the leg.
CLI is different. Blood flow drops so low that the tissue in the foot and lower leg cannot get what it needs, even at rest. As a result, cells begin to break down, and wounds cannot heal. Over time, tissue can die. This is called gangrene.
In other words, the move from claudication to CLI is not just a matter of degree. It is a shift from discomfort to danger. With claudication, we have time to work through options. With CLI, the clock is already running.
How PAD Turns Into CLI
Most cases of CLI do not appear out of nowhere. Instead, they develop when PAD goes unnoticed or undertreated for years. At some point, the remaining blood flow is no longer enough to keep the tissue alive.
Sometimes a new event tips the balance. For example, a blood clot can lodge in an already narrow artery and block what little flow remained. A small cut on the foot that would heal in a healthy person can become a wound that will not close. An infection can make things worse.
Diabetes also raises the risk even further. Diabetic nerve damage can hide pain, so CLI may be well underway before a patient notices it. I explain this connection in my article on diabetes and PAD.
Warning Signs of CLI
Recognizing CLI early can make the difference between saving a limb and losing it. For this reason, these are the signs I ask patients and families to watch for:
- Rest pain. This is a burning or aching pain in the foot and toes that does not go away when you sit or lie down. It is also often worst at night. Many patients tell me they hang their foot off the bed for relief. Rest pain that improves when the leg hangs down is a hallmark of CLI.
- Wounds that will not heal. Sores on the toes, heels, or feet that do not improve over a few weeks are a red flag. These are often arterial ulcers.
- Skin changes. The foot may look pale when raised, or dusky and blotchy when lowered. In addition, the skin may become shiny and thin. Hair loss on the lower leg and thick toenails are also common.
- Weak or missing pulses. In a healthy leg, I can feel a pulse on the top of the foot. With CLI, it is often faint or missing.
- Numbness, tingling, or weakness. Nerves and muscles need blood, too, so they suffer as well. Some patients notice a heavy or weak foot.
- A cold foot. A foot that feels much colder than the other one is a sign of poor circulation.
Why CLI Is a Limb Emergency
I want to be direct: critical limb ischemia is not a condition to watch and wait on. After all, a foot with CLI is already under extreme stress. Every day without enough blood flow adds more damage. Wounds can become infected, and infection can lead to gangrene. A problem that could have been treated with a procedure early on may require amputation later.
CLI also signals a higher risk to your heart. The same plaque that blocks the leg arteries often affects the arteries of the heart and brain. According to the National Heart, Lung, and Blood Institute, people with PAD have a higher risk of heart attack and stroke.
Over the years, I have seen patients wait months before coming in. Some blamed arthritis, for example. Others did not want to bother anyone. By the time I saw them, they had fewer options. On the other hand, patients who came in at the first sign of rest pain or a slow-healing wound often had more choices, and we could focus on restoring blood flow. So if you notice any of these warning signs, please do not wait to see if they improve.
How I Diagnose CLI
When a patient comes to me with signs of CLI, my first goal is to understand exactly what is happening. To do that, I start with a detailed history and a physical exam. I want to know when the symptoms began, how they have changed, and what other health conditions are present.
Next, I use simple tests to measure blood flow:
- An ankle-brachial index test, which compares blood pressure at the ankle and arm
- Toe pressures, which are helpful when diabetes stiffens the arteries
- A duplex ultrasound, which shows where the blockages are
In many cases, I also use CT angiography or MR angiography to create a detailed map of the arteries before treatment. After that, I sit down with you and explain what I found in plain language. You should understand your situation and feel confident in the plan we build together.
Critical Limb Ischemia Treatment Options
Above all, the goal of treatment is to restore blood flow before the damage becomes permanent. My plan depends on where the blockages are, how severe they are, and your overall health. Often, the best approach combines more than one tool because each blockage is different.
As an interventional radiologist, I treat blockages from inside the artery through a small puncture, usually in the groin. There is no large incision, and recovery is usually much faster than with open surgery. Depending on the blockage, I may use:
- Angioplasty, which opens the narrowed artery with a small balloon
- Stenting, which places a small mesh tube to help keep the artery open
- Atherectomy, which removes hard or calcified plaque from inside the artery
For some patients, the blockages are too long or complex for a catheter-based approach. In those cases, bypass surgery by a vascular surgeon may be the better option, and I help coordinate that referral.
Restoring blood flow is the most important step. Even so, wounds that have been open for weeks still need careful wound care to heal. That care may include special dressings, removal of dead tissue, treatment of infection, and taking pressure off the foot. I work closely with wound care teams and podiatrists so that every part of the plan fits together.
Preventing CLI and Protecting Your Legs
Of course, the best way to deal with CLI is to keep PAD from getting that far. These steps make the biggest difference:
- Quit smoking. Tobacco damages and narrows blood vessels. Quitting smoking is the most powerful step you can take.
- Control diabetes, blood pressure, and cholesterol. Take your medications as prescribed, and keep up with your checkups as well.
- Walk every day. Regular walking improves circulation and helps your body build small natural detours around blockages.
- Eat a heart-healthy diet. Focus on vegetables, fruits, whole grains, and lean proteins, and limit salt and added sugar.
- Care for your feet. Check them daily for cuts, color changes, or sores. Wear well-fitting shoes, and see a podiatrist for nail and callus care.
- Get screened. If you have risk factors, an ABI test can find PAD before it becomes severe.
Care From the Same Doctor at Every Step
CLI is one of the most serious conditions I treat. Still, it is also one of the most treatable when we catch it in time. Coastal Vascular Center is a small, physician-owned practice, not a corporate chain. You see me at every visit, and I personally perform every procedure, so you never get handed off along the way.
Get a CLI Evaluation With Dr. Ayar
If you have foot pain at rest, a wound that is not healing, or cold, discolored toes, please call us as soon as possible. I check your blood flow and explain your options clearly. You will see Dr. Ayar at every visit in Pearland or Lake Jackson.
