Gettysburg Medical News
 The Clinical View
 by P. E. Hoffsten, MD
 30 November 2005

WHAT IS THE ANKLE BRACHIAL INDEX?

The gentleman was 64 years of age and a person who had always been physically vigorous.  He was a rancher who rode 4-wheelers and horses and had no difficulty walking until recently.  In the past several months, he had noticed that his feet were colder than usual, even though it was summertime, and then his calves seemed to ache a great deal when he was active.  Like all standard South Dakota males, he figured it was just aging, or it would go away, or he would worry about it another time.

          Then fate intervened.  His 4-wheeler broke down about a mile from home and try as he would, he couldn’t get it started again.  He didn’t carry a cell phone with him so he got to walk home.  He recalls that by the time he got home, both calves were hurting so bad he could hardly walk.  Both calves would become unusually hard and painful.  He took off his boots to rub his legs and noticed that his feet were very blue.  This was enough to get him to come to the clinic.

          At the clinic, it was found that he had high blood pressure at 160/90 and his cholesterol was 260 milligrams percent with a bad cholesterol (LDL) of 173 milligrams percent.  His blood sugar was normal, but he was a pack-a-day smoker.  He took no medications.

          He was seen in the clinic by one of the certified Nurse Practitioners who obtained the history as above.  She explained to him that the symptoms he was having were related to “peripheral arterial disease.”  She explained that just as people get strokes and heart attacks, blood vessels to the head or the heart get stopped up, blood vessels to the legs can also get stopped up and cause the exact symptoms that this gentleman was having.  The blood vessels get stopped up from plaque and cholesterol clogging the arteries.  This gentleman had three of the four major risk factors with his high blood pressure, high cholesterols, and smoking history.  Fortunately, he was not diabetic.

          It was explained to him that he needed to have an ankle brachial index test done to determine how to treat the problem.  The test was scheduled in the next week.  In the interval, he was instructed to start a blood pressure pill, start a cholesterol pill, start taking an Aspirin per day, and quit smoking.

          Three new medicines, a test he didn’t understand, and stopping the smoking habit he had since age 12 boggled his mind.  He had to have a second opinion and came to see me wondering what an ankle brachial index was and how it was going to help his problem.

          I first reviewed his visit with the Nurse Practitioner and told him everything she said was “right on.”  In a busy clinic with so much new information being offered, patients often don’t hear the whole message.  I explained to him that peripheral arterial disease comes in two basic forms.  In one form, the blood vessels are stopped up high in the leg so that blood doesn’t get down to the lower leg and the foot.  This type of problem can be fixed with surgery to unblock the big blood vessels in the upper leg.  The other form of peripheral arterial disease is what we call small vessel disease in which the little arteries down in the foot and the lower leg are stopped up.  Unfortunately, there is no surgery available to help this problem and medications and lifestyle change are the only treatments available.

          I then explained that the ankle brachial index test was really very simple.  It is basically a comparison of the blood pressure between the arm and the leg.  Blood pressure in the legs should be just slightly higher than blood pressure in the arms.  Thus if one finds a blood pressure of 130 systolic in the arms, blood pressure in the legs would be expected to be 130 to 135 millimeters of mercury.  When the blood pressure in the arms is much higher than the blood pressure in the legs, that is a sign that there are obstructions in the arteries leading to the legs.  In this particular gentleman, his arm pressure a week after starting the medication was still slightly high at 145 millimeters of mercury systolic pressure.  The blood pressure in his upper thigh was slightly lower at only 130 millimeters of mercury pressure.  The blood pressure in his calf and his ankle were very low at only 62 millimeters of mercury systolic pressure.  Thus in this particular gentleman, the blood pressure in the upper leg was slightly impaired, but there is not a surgically correctible lesion.  The blood pressure in the lower leg was substantially impaired and unfortunately the use of medication and lifestyle change (stopping smoking) were the only treatments available.

          Then came the battle.  His opinion was that medications weren’t “natural.”  He didn’t want to be taking medications because they would cause side effects and he didn’t know if he could quit smoking.  As gently but as firmly as I could, I explained to him that natural in his case involved high blood pressure, high blood cholesterol, and the blood vessel spasming due to the effects of cigarettes.  This was “naturally” going to lead to an amputation of one or both feet sometime in the future.  That word “amputation” finally seemed to get his attention.  He was told that he could use the medicines and keep on smoking with a predictable amputation of his feet in the future or he could try the medications, stop his smoking, and have the best chance of keeping his feet from the pain when walking.  He wanted to know what kind of guarantees I could give him and I told him there were none.  But I did say that it is a testable idea.  Try the medication for several months and see if the pain in his legs gets better, see if his feet warm up.  Winter is coming and will provide a stout test for the effectiveness of my recommendations.  With little enthusiasm, he agreed to try the idea. We will know better in a few months how this works.

          In summary, the ankle brachial index is a very simple test in which the blood pressures in the arms and the legs are compared.  A comprehensive and competent test requires special equipment, but the test is available in central South Dakota and can be scheduled through your local clinics.  Having a foot amputated because of peripheral arterial disease is very disappointing and unlike some hazards, I have never seen a foot grow back on a human.  Prevention is the answer and dealing with the problem appropriately early can be limb saving.