4.12 Peripheral arterial disease, as determined by appropriate medically acceptable imaging (see 4.00A3d, 4.00G2, 4.00G5, and 4.00G6), causing intermittent claudication (see 4.00G1) and one of the following:

Peripheral arterial disease (PAD) is when arteries, in this case, to the legs, becomes fully or partially blocked. This blockage most commonly occurs due to atherosclerotic (cholesterol) plaques.  

Arterial blood brings oxygen and nutrients to the muscles of the legs, and when blocked may results in pain in the legs, also called intermittent claudication. Intermittent claudication is typically described as pain in your calf after walking a distance that goes away when you rest. In advanced peripheral arterial disease, you may have pain in your legs at rest, and you may develop leg ulcers and gangrene.

Appropriate medically acceptable imaging studies to diagnose PAD includes arterial Doppler ultrasound, strain-gauge plethysmography, and angiography (dye is shot through a catheter into the arteries and nuclear images are taken).

An arterial Doppler study is most commonly used by SSA to determine whether PAD is Listing level. An arterial Doppler taken while you are at rest is the most common screening test for PAD and measures blood flow through the arteries in the legs and arms. The ankle/brachial systolic blood pressure ratio (also called ankle/brachial index) measures the systolic blood pressure in the brachial artery of the arm and compares it to the systolic blood pressures of the posterior tibial and dorsalis pedis arteries of the legs.

The higher (better) of the pressures in the posterior tibial artery or the dorsalis pedis arteries of the legs is used in deciding the ankle/brachial systolic blood pressure ratio.
 
A. Resting ankle/brachial systolic blood pressure ratio of less than 0.50.

In 4.12A, the ankle/brachial systolic blood pressure ratio (or ankle/brachial index) is the ratio of the systolic blood pressure at the ankle (higher of the posterior tibial or dorsalis pedis pressure) to the systolic blood pressure at the brachial artery; both taken at the same time while you are lying on your back. SSA does not require that the ankle and brachial pressures be taken on the same side of your body. This is because, as with the ankle pressure, SSA will use the higher (better) brachial (arm) systolic pressure measured.

Listing 4.12A is met when your resting ankle/brachial systolic blood pressure ratio is less than 0.50.

OR

B. Decrease in systolic blood pressure at the ankle on exercise (see 4.00G7a and 4.00C16-4.00C17) of 50 percent or more of pre-exercise level and requiring 10 minutes or more to return to pre-exercise level.

If your resting ankle/brachial systolic blood pressure ratio is 0.50 or above, SSA will use 4.12B to evaluate the severity of your PAD, unless you also have a disease causing excessive calcification in the arteries or small vessel disease (blocked small arteries), such as diabetes mellitus.

SSA will generally purchase exercise Doppler studies when your resting ankle/brachial systolic blood pressure ratio is at least 0.50 but less than 0.80, and only rarely when it is 0.80 or above. Because any exercise test stresses your entire cardiovascular system, SSA will purchase exercise Doppler studies only after an SSA medical consultant, preferably one with experience in the care of patients with cardiovascular disease, has determined that the test would not present a significant risk to you and that there is no other medical reason not to purchase the test

If the systolic blood pressure at the ankle with exercise decreases 50 percent or more compared to pre-exercise (resting) level, and takes 10 minutes or more to return to the pre-exercise level, you meet Listing 4.12B.

OR

C. Resting toe systolic pressure of less than 30 mm Hg (see 4.00G7c and 4.00G8).

SSA may not purchase exercise Doppler testing if you have a disease that results in abnormal arterial calcification or small vessel disease, but may use your resting toe systolic blood pressure.
 
SSA may use resting toe systolic blood pressure when you have intermittent claudication and a disease that results in abnormal arterial calcification (for example, Monckeberg’s sclerosis or diabetes mellitus) or small vessel disease (for example, diabetes mellitus). This is because these diseases may result in falsely high blood pressure readings at the ankle. And because high blood pressures due to vascular changes related to these diseases seldom occur at the toe level.

If your resting toe systolic blood pressure is less than 30 mm Hg, you meet 4.12C.

There are no current medical standards for evaluating exercise toe pressures, however toe pressures can be measured by photoplethysmography; less frequently, plethysmography using strain gauge cuffs; and Doppler ultrasound. Toe pressure can also be measured by using any blood pressure cuff that fits snugly around the big toe and is neither too tight nor too loose. A neonatal (baby) cuff or a cuff designed for use on fingers or toes can be used in the measurement of toe pressure.

OR

D. Resting toe/brachial systolic blood pressure ratio of less than 0.40 (see 4.00G7c).

SSA may use resting toe/brachial systolic blood pressure ratios (determined the same way as ankle/brachial ratios) when you have intermittent claudication and a disease that results in abnormal arterial calcification (for example, Monckeberg’s sclerosis or diabetes mellitus) or small vessel disease (for example, diabetes mellitus). This is because these diseases may result in falsely high blood pressure readings at the ankle. However, high blood pressures due to vascular changes related to these diseases seldom occur at the toe level.
 
If your resting toe/brachial systolic blood pressure ratio is less than 0.40, you meet Listing  4.12D.

While the criteria in 4.12C and 4.12D are intended primarily for individuals who have a disease causing abnormal arterial calcification or small vessel disease, SSA may also use them for evaluating anyone with PAD.

In my experience, SSA rarely uses toe pressures (Listing 4.12 C and D) to determine disability, even with diabetes mellitus.


Peripheral grafting and PAD:

Peripheral grafting serves the same purpose as coronary grafting; that is, to bypass a portion of a narrow or obstructed artery. If intermittent claudication recurs or persists after peripheral grafting, SSA may purchase Doppler studies to assess the flow of blood through the bypassed vessel and to establish the current severity of your PAD.

However, if you have had peripheral grafting done for your PAD, SSA will not use the findings from before the surgery to assess the current severity of your PAD, although SSA will consider the severity and duration of your impairment prior to your surgery in making their decision.