Why Patients with Chronic Kidney Disease are at Risk for PAD
Dr. Joseph Shams has been specializing in endovascular care for almost 30 years. In this interview, Dr. Shams discusses why patients with chronic kidney disease are at a greater risk of developing Peripheral Artery Disease.
What is the Prevalence of Patients who have Chronic Kidney Disease and Peripheral Artery Disease?
Peripheral Artery Disease (PAD) in the United States today is approximately 5%. This includes patients who may or may not be symptomatic at the time, but if you screened them, you’d find about 5% of them have peripheral artery disease. If you look at a smaller subset of patients, who are 70 or older, you’d diagnose 15% of them with peripheral artery disease.
The combination of peripheral artery disease and chronic kidney disease is based on the number of patients who are borderline, meaning they are at stage three or stage four of kidney disease and not on dialysis yet. But because there is evidence of significant kidney disease, about 25% of those patients will also have peripheral artery disease. When you look at patients who are on dialysis, up to 45% of those patients will have PAD.
What are the Symptoms that Most Patients with PAD Present With?
There are four stages of peripheral artery disease. Patients, as we noted, may be completely asymptomatic but walking around with blockages in the arteries in their legs.
As a result, the first symptom that may present in patients is calf claudication. This means that when they walk a block or two, they start developing pain in the back of their legs. This pain requires them to stop and rest for a few minutes before they can start walking again. When they’re at rest, they have no symptoms. When they stress their body by walking, they need more blood flow. Their arteries can’t provide the blood flow that’s needed because of the blockages, and therefore the patient experiences pain.
In patients with chronic kidney disease, only 30% of them will develop claudication. But 70% of them will actually present with later stages of the disease, including but not limited to rest pain, meaning they experience pain in their toes when they’re at rest. For example, if a patient is lying in bed, they may feel severe pain in their toe. This pain requires them to shake their leg, rub their toes, or move their leg over the bed so gravity will help get the blood down to their toes.
In later stages, ulceration can occur. Patients may get a wound or a small cut in the foot or the toes when they cut their toenails. If this wound doesn’t heal, it may become infected. This progression is much more typical for patients with chronic kidney disease. The last stage is gangrene, where the toe turns black and may not be able to be salvaged.
Patients who are diabetic or in late-stage kidney failure may also develop neuropathy. They may not be able to feel their feet or their toes. This nerve problem may result in them falling, not being able to walk properly, experiencing balancing issues, and ultimately damaging the bones and tissues in their legs.
Are Chronic Kidney Disease Patients More at Risk of Progressive PAD or Critical Limb Ischemia?
The three categories of patients that develop peripheral artery disease far down in the leg include elderly patients usually over the age of 80, patients with diabetes mellitus, and patients with chronic kidney disease.
The reason peripheral artery disease is so prevalent in patients with chronic kidney disease is due to high phosphate levels and homocysteine levels. Even if patients are on dialysis, and they’re getting good dialysis, they can get a particular type of disease with calcification that can form in the low part of the leg. The reason why that’s of concern is that it’s easier to treat larger blood vessels. As the blood vessels get smaller and smaller, they can block up much easier. Therefore, a patient who presents with peripheral artery disease, in general, has only a 5% risk of losing their limb over the next five years. But a patient who has kidney disease and presents with Critical Limb Ischemia may actually have a 50% one-year limb loss rate. It’s critical these patients are treated.
It’s also important to point out that patients who present with chronic kidney disease and peripheral artery disease are at high risk of developing blockages in their heart. We have to identify those patients right away and treat them because of a heart condition.
In addition to chronic kidney disease, smoking also increases the risk of peripheral artery disease. However, in smokers, peripheral artery disease can occur in the bigger blood vessels in the abdomen and the groin regions.
Why Should Chronic Kidney Disease Patients be Concerned if They Have PAD?
As we noted, up to almost 50% of patients with chronic kidney disease can develop peripheral artery disease. In fact, they tend to develop the more severe presentations of peripheral artery disease including ulceration, infections, and even limb loss. A patient who has an ulcer on their toe that’s not healing may have up to a 30% chance of losing that limb, requiring a major amputation within the next year. Patients have to be aggressively seen and treated.
If a Patient Has Chronic Kidney Disease and Non-Healing Wound, How Quickly Should They Schedule an Appointment?
They should be seen immediately either by their podiatrist or primary care physician. Usually, these physicians are aware of the vascular disease and can do very simple screening tests to check pulses and Doppler. The Doppler is a signal in the blood vessels in the leg and foot that indicate vascular insufficiency. Patients with vascular insufficiency should be treated right away. Unfortunately, particularly in patients who have chronic kidney disease and diabetes mellitus, lesions can progress rapidly.
If they do become infected they can spread to other parts of the foot and may be difficult to treat, especially if they’re not getting enough blood flow. If there’s not enough blood flow to a site, particularly in the toes and the feet, it’s a good medium for bacteria to grow. Even if a small amount of bacteria starts taking hold, it can progress rapidly to a severe situation. I’ve had patients who were completely fine one day and then developed a tiny wound and within a week they developed full gangrene and a black toe.
If a patient needs a procedure with American Endovascular, what can they expect?
When I started my training, most treatments for Peripheral Vascular Disease required bypass surgery. This is when a blood vessel is closed. In order to treat it, we have to create a new blood vessel channel to bypass the area of the blockage. Bypass surgery is usually performed with a synthetic piece of Teflon tube, sterile tube, or actual veins from the patient. We’d use this material to connect one artery piece to another artery piece. The problem with bypass surgery is that it’s a major operation. Patients require hospitalization for up to several weeks. If they have a history of cardiac disease or other problems, bypass surgery can induce a heart attack. Also, the patency rates, meaning how long the arteries stay open, are a concern.
However, over the past 20-25 years, we’ve developed and refined endovascular techniques which are now minimally invasive. Today we go directly into the blood vessels, either from the arm or the leg, and treat it internally—instead of having to do bypass surgery. This is all done in an outpatient setting and with minimal anesthesia, which is a twilight-type of anesthesia. The procedure takes about an hour to an hour and a half. The patient will lie down for two hours after the test and then go home. The patient may feel a little tired the next day, but otherwise, there’s basically no recovery.
Why are American Endovascular Doctors Successful in Treating Non-Healing Wounds in Patients?
I myself have been treating dialysis patients for about 25 years in a university setting and also in the outpatient setting. I see about one thousand dialysis patients per year – treating their accesses, maintaining their accesses, and inserting catheters. I know these patients; I know the type of disease we’re dealing with. For example, patients who have minimal renal function may not be able to receive the dye that we usually use for these procedures. Instead, we can use a special carbon dioxide dye and spare the patient any side effects.
In addition, many physicians are not comfortable dealing with the diseases our patients present with. In many cases, these diseases require treating the lesions in the tiny blood vessels. Patients who get a disease in the larger blood vessels are much easier to treat. The difficulty is treating the tiny little blood vessels below the knee and into the foot. The physicians at American Endovascular have been dealing with more complicated cases for years. We’ve refined new techniques that can go directly into the foot vessels from the foot itself and even down deep into the toes. With these newer techniques, we can salvage legs and feet that would otherwise require a major amputation.
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