Peripheral Arterial Disease

In the human body, blood circulates from the heart to the different parts of the body and back to the heart. This circulation continues throughout life. Blood circulates in special tubes that go to every part of the body. Fresh blood (which is rich in oxygen and nutrients) travels from the heart to the peripheries by tubes called arteries. In the peripheries, tissues such as muscles, skin and bones use up the oxygen and nutrients. The blood becomes poor in oxygen and nutrients. It has more carbon-dioxide and wastes dissolved in it. This “impure” blood returns back to the heart for re- oxygenation. The tubes that carry the “impure” blood back to the heart are called as veins.

What is Peripheral Arterial Disease?

Arteries are the tubes that connect the heart with the different tissues of the body. They carry fresh blood rich in oxygen from the heart to the different tissues such as muscles, bones and internal organs of the body. 

Arterial disease commonly involves blockage of these tubes. Less commonly, the artery may undergo ballooning, which is called an “aneurysm”. 

Blockage of arteries supplying a part of the body reduces the blood flow to that part. For example, if the artery which supplies blood to the leg is blocked, foot gangrene and infection will result. In other words, the foot undergoes rotting (leg attack). Blockage of leg arteries is one of the commonest vascular problems among Indians. The problem of blockage of peripheral arterial disease is made more severe by diabetes. India is the diabetic capital of the world.

What are the symptoms and signs of Peripheral Arterial Disease (PAD)?

PAD can manifest in a variety of ways. The mildest form is “claudication pain”. This is pain in the calf, thigh or buttock which appears when the person walks or exercises and disappears with rest. It is a sign that the muscles are not getting adequate blood supply at the time of exertion. This stage is mostly treated by medications but may need intervention if severe. As the disease progresses, the patient will develop infections or wounds which fail to heal. Some patients develop gangrene of the involved extremity (rotting due to lack of blood supply). This can be limb / life threatening. It needs immediate intervention by a vascular surgeon. 

How is PAD investigated?

The vascular surgeon will take a decision depending upon the clinical situation. Generally, the first test is an ultrasound scan of the arterial circulation called as a Duplex or colour doppler scan. If there is a severe block and tissue loss (infection/wound/gangrene), an angiogram will be performed. This is a special test where the arteries are imaged and blockages are visualised. There are three types of angiogram commonly performed. These are conventional angiogram, MRI angiogram and CT angiogram. A conventional angiogram is the gold standard. It involves injection of a special contrast medicine that shows up on X-ray. When it is being injected into the artery, X-rays are taken and the image of the artery is visualised on a special screen. MRI angiogram is a type of angiogram where an MRI scan is done to get a computer generated view of the arteries. MR angiogram is steadily improving in quality of images and replacing conventional angiograms in some situations. A CT scan is a specialised type of Xray machine that can generate images of the tissues using X-Rays.

How can PAD be treated?

Blocked arteries in the leg can be treated by either medications or surgery or both. The best method of treatment can be decided only after a thorough evaluation of the patient. Surgery commonly involves a bypass operation. Yes, bypass operations can be done not only in the heart but also in the leg. After all gangrene of the leg is “ leg attack” just like a block in the arteries of the heart causes a “heart attack” . Leg attack can be as devastating as a heart attack! 

Some people with blocked lower limb arteries can be treated with a newer method of treatment called endovascular surgery (minimally invasive ). Here, the morbidity of open operations can be avoided by performing an “angioplasty and stenting” of the blocked blood vessel. Not everyone is a suitable candidate for endovascular surgery. The vascular surgeon is the best person to decide which form of surgery (open or endovascular) is best suited to a particular patient. 

Also it is important to remember that vascular surgery attempts to clear blockages and to retard the progress of disease. It will not cure the basic causes of the disease such as diabetes and atherosclerosis. Because the patients co-morbidities continue to exist, these patients will need regular monitoring in order to ensure that the bypassed or angioplastied artery continues to remain patent. 

Vascular surgery is performed in order to improve the blood flow to the leg and stop further spread of gangrene. This can be limb saving as well as life saving.

What is this “aneurysm” you referred to earlier?

An aneurysm is a localised ballooning of the artery. It is deadly because the ballooned out blood vessel can burst and have fatal consequences. Luckily, we Indians have a lower incidence of aneurysms compared to people in western countries.