Peripheral Arterial Disease (PAD) is a very common disease that most Americans know little about and is probably under appreciated by even some physicians. PAD is defined as narrowing of the arteries that supplies blood to organs other than the heart, most commonly referring to arteries of the lower extremities. PAD of the upper extremity can occur, however it is relatively uncommon.
Most typically, PAD refers to atherosclerosis of the arteries that provide blood to the thighs, buttock and calves. This article will introduce some of the basics about this all too under appreciated condition.
The incidence of PAD has significantly increased in recent years. This is probably due to that fact that Americans are living longer and that Baby Boomers are now entering the age when PAD is very common. The prevalence of PAD sharply rises with advancing age, from 0.9 percent in the 40- to 50-year-old population, to as high as 14.5 percent in those older than 70. Statistics performed in 2007 show that there are some 27 million people in the United States and Europe with PAD, accounting for nearly one half of a million hospital admissions each year for complications of PAD.
PAD is most commonly due to atherosclerosis of the arteries of the lower extremities. Atherosclerosis occurs when fat, cholesterol and atherogenic substances coalesce to form an adherent plaque on the inner lining of the blood vessels. As this plaque grows and causes progressive narrowing of the blood vessels, there is a resultant decrease in blood supply to that organ. This lack of blood supply results in muscle pain with exertion, as the muscle's increased demand out strips the relatively fixed blood supply.
It is analogous to the process that affects the coronary arteries of the heart, and like angina, progressive narrowing of the lower extremity arteries can cause pain of the legs with exertion. Analogous to a heart attack, the growing plaque in the lower extremity arteries can suddenly rupture and result in total occlusion of forward blood supply. This can result in an acutely cold lower extremity, numbness and tingling, and ultimately result in gangrene and limb loss.
The risk factors for PAD are similar to those of atherosclerosis in general, yet other causes of PAD must be considered. The risk factors of PAD include: tobacco use, elevated cholesterol, long standing hypertension, poorly controlled diabetes, a history of heart disease and strokes and advanced age.
The overlap of risk factors for PAD and heart disease are so close that PAD is an independent risk factor for coronary artery disease.
The non-atherosclerotic causes of PAD include; inflammatory conditions of the arteries, localized trauma, medications that cause arterial spasm and localized radiation of the extremities or pelvis. These all result in narrowing of blood vessels and the resultant symptoms of PAD.
Patients with PAD can be completely asymptomatic until severe narrowing occurs. When this happens, patients commonly develop pain in the large muscles of the buttock, thighs, calves and rarely feet. The pain is usually triggered by exercise and relieved by rest.
Although it can affect both lower extremities, it classically seems to affect one side more severely. The pain also seems to occur at an almost exact same level of exercise, whether this is at the same part of one's walk or at the same stage of a treadmill workout. The pain classically abates gradually with rest, such as stopping for a few minutes, will allow for the fixed blood supply to catch up with the reduced metabolic demands of the resting muscles. This classic type of leg pain is called intermittent claudication, which can be thought of as angina of the legs.
Much as angina can be a harbinger of a heart attack, intermittent claudication may pre-date a sudden and complete obstruction of blood supply to a muscle or an entire lower extremity. In this very dangerous state, a sudden loss of blood flow can result in critical limb ischemia with the possibility of gangrene and loss of the limb. As leg pain has many causes, it is critical to alert your physician of any signs of leg pain that are new so that appropriate diagnostic testing can be performed.
The initial evaluation for PAD starts with a comprehensive history and physical examination. Actually, a thorough history can nearly synch the diagnosis of PAD, with basic testing only confirming the initial diagnosis. The physical exam will usually start with an evaluation for a cool leg, hair loss in the lower extremity, signs of poor blood refilling when pressure is released from a compressed extremity.
PAD can more objectively be picked up with an ABI, which stands for Ankle Brachial Index. In this simple test, blood pressure in the ankle is compared to the blood pressure in the arm. The larger the discrepancy between these blood pressures, the more severe the PAD.
The next test commonly performed is Doppler ultrasound imaging of the legs, called a Duplex. This non-invasive test uses sound waves to image the arterial blood flow and detect areas of narrowing. If the Duplex is inconclusive, a physician can also perform a Computed Tomography with IV contrast (CT Angiography) to very accurately visualize the arteries.
Another imaging technique is Magnetic Resonance Angiography with an IV contrast (MRA), which is a safe non-invasive procedure that can very accurately detect blockages in the lower extremities.
If a corrective procedure is planned, a cardiologist, vascular surgeon or interventional radiologist can perform an invasive procedure called an angiogram. During the angiogram, the physician will use injections of contrast into the arteries and visualize any blockages with X-ray movies.
Sometimes, these blockages are amenable to ballooning and stent deployment, which will increase downstream blood flow.
In cases of severe PAD, surgical bypass procedures can be very effectively utilized. A lower extremity bypass surgery consists of surgically grafting a blood vessel before a site of narrowing and then just beyond the blockage, effectively bypassing the narrowing and circumventing the obstruction of blood flow.
In summary, PAD is a very common and possibly debilitating disease that is often over-looked until the disease has developed beyond easy repair. As with similar diseases of the vascular system, PAD can be very effectively diagnosed and treated with a combination of medications, invasive procedures and graded exercise.
Talk to your physician if you have any of these symptoms, as an early diagnosis and treatment is critical.
Dr. David M. Donaldson is an Auburn native and currently a
cardiologist at Massachusetts
General Hospital in Boston
The incidence of PAD has significantly increased in recent years. This is probably due to that fact that Americans are living longer and that Baby Boomers are now entering the age when PAD is very common. The prevalence of PAD sharply rises with advancing age, from 0.9 percent in the 40- to 50-year-old population, to as high as 14.5 percent in those older than 70. Statistics performed in 2007 show that there are some 27 million people in the United States and Europe with PAD, accounting for nearly one half of a million hospital admissions each year for complications of PAD.
PAD is most commonly due to atherosclerosis of the arteries of the lower extremities. Atherosclerosis occurs when fat, cholesterol and atherogenic substances coalesce to form an adherent plaque on the inner lining of the blood vessels. As this plaque grows and causes progressive narrowing of the blood vessels, there is a resultant decrease in blood supply to that organ. This lack of blood supply results in muscle pain with exertion, as the muscle's increased demand out strips the relatively fixed blood supply.
It is analogous to the process that affects the coronary arteries of the heart, and like angina, progressive narrowing of the lower extremity arteries can cause pain of the legs with exertion. Analogous to a heart attack, the growing plaque in the lower extremity arteries can suddenly rupture and result in total occlusion of forward blood supply. This can result in an acutely cold lower extremity, numbness and tingling, and ultimately result in gangrene and limb loss.
The risk factors for PAD are similar to those of atherosclerosis in general, yet other causes of PAD must be considered. The risk factors of PAD include: tobacco use, elevated cholesterol, long standing hypertension, poorly controlled diabetes, a history of heart disease and strokes and advanced age.
The overlap of risk factors for PAD and heart disease are so close that PAD is an independent risk factor for coronary artery disease.
The non-atherosclerotic causes of PAD include; inflammatory conditions of the arteries, localized trauma, medications that cause arterial spasm and localized radiation of the extremities or pelvis. These all result in narrowing of blood vessels and the resultant symptoms of PAD.
Patients with PAD can be completely asymptomatic until severe narrowing occurs. When this happens, patients commonly develop pain in the large muscles of the buttock, thighs, calves and rarely feet. The pain is usually triggered by exercise and relieved by rest.
Although it can affect both lower extremities, it classically seems to affect one side more severely. The pain also seems to occur at an almost exact same level of exercise, whether this is at the same part of one's walk or at the same stage of a treadmill workout. The pain classically abates gradually with rest, such as stopping for a few minutes, will allow for the fixed blood supply to catch up with the reduced metabolic demands of the resting muscles. This classic type of leg pain is called intermittent claudication, which can be thought of as angina of the legs.
Much as angina can be a harbinger of a heart attack, intermittent claudication may pre-date a sudden and complete obstruction of blood supply to a muscle or an entire lower extremity. In this very dangerous state, a sudden loss of blood flow can result in critical limb ischemia with the possibility of gangrene and loss of the limb. As leg pain has many causes, it is critical to alert your physician of any signs of leg pain that are new so that appropriate diagnostic testing can be performed.
The initial evaluation for PAD starts with a comprehensive history and physical examination. Actually, a thorough history can nearly synch the diagnosis of PAD, with basic testing only confirming the initial diagnosis. The physical exam will usually start with an evaluation for a cool leg, hair loss in the lower extremity, signs of poor blood refilling when pressure is released from a compressed extremity.
PAD can more objectively be picked up with an ABI, which stands for Ankle Brachial Index. In this simple test, blood pressure in the ankle is compared to the blood pressure in the arm. The larger the discrepancy between these blood pressures, the more severe the PAD.
The next test commonly performed is Doppler ultrasound imaging of the legs, called a Duplex. This non-invasive test uses sound waves to image the arterial blood flow and detect areas of narrowing. If the Duplex is inconclusive, a physician can also perform a Computed Tomography with IV contrast (CT Angiography) to very accurately visualize the arteries.
Another imaging technique is Magnetic Resonance Angiography with an IV contrast (MRA), which is a safe non-invasive procedure that can very accurately detect blockages in the lower extremities.
If a corrective procedure is planned, a cardiologist, vascular surgeon or interventional radiologist can perform an invasive procedure called an angiogram. During the angiogram, the physician will use injections of contrast into the arteries and visualize any blockages with X-ray movies.
Sometimes, these blockages are amenable to ballooning and stent deployment, which will increase downstream blood flow.
In cases of severe PAD, surgical bypass procedures can be very effectively utilized. A lower extremity bypass surgery consists of surgically grafting a blood vessel before a site of narrowing and then just beyond the blockage, effectively bypassing the narrowing and circumventing the obstruction of blood flow.
In summary, PAD is a very common and possibly debilitating disease that is often over-looked until the disease has developed beyond easy repair. As with similar diseases of the vascular system, PAD can be very effectively diagnosed and treated with a combination of medications, invasive procedures and graded exercise.
Talk to your physician if you have any of these symptoms, as an early diagnosis and treatment is critical.
Dr. David M. Donaldson is an Auburn native and currently a
cardiologist at Massachusetts
General Hospital in Boston
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