Vascular Workup (Non-Invasive)
Contributing Author, Cardiothoracic Surgeon
Many patients complain to their physicians that they have “poor circulation.” In the old days, little could be done to help this group of patients. Often, the patient is in their 60ties or 70ties and has multiple other problems that may cloud the picture. They often have lumbar back pain and may have pain radiating down into their legs from degenerative disc disease of the spine or arthritis in their hip or knee joints. The central question remains. Can anything be done to determine if the blood vessels in their legs are diseased and symptomatic and if so can anything be done to fix the problem?
Let us start by saying that the explosion of information resulting from the development of Doppler exams, plethysmography, and echo technology has given us new hope. The entire field of vascular disease has become more scientifically based. Many vascular surgeons have established vascular labs in their offices to provide anatomic and functional information that can be used in treating patients with suspected peripheral arterial or venous disease.
If your legs hurt when you walk short distances, if your feet hurt all the time or if you are awakened from sleep with leg pain, you probably need a work-up to determine the status of your peripheral vessels. The first and perhaps the simplest test in your work-up is called a segmental pressure test or an ankle brachial index. By measuring the blood pressure at the ankle, calf and thigh in each leg and dividing that number by the systolic blood pressure in the arm, the ABI (ankle brachial index) can be determined.
Normally, the pressure at each level in the legs should be the same as the arm pressure. If it is not, a blockage or a stenosis may be present in the artery. For example if the ankle BP is 120 and the arm pressure is 120 then the ABI is 1 (120/120 = 1). If the ankle pressure is 100 and the arm pressure is 150 mm, then the ABI would decrease to 0.66 (100/150 = .66). In this case 66% of the normal blood flow would find its way to the ankle as a result of stenosis up stream from the ankle.
Due to various flow factors, a stenosis becomes more significant with exercise. So that the leg may not hurt when you are sitting in your chair, but it may begin to hurt when you walk to the mailbox. The lower the ABI score, the more severe the blockage. If the ABI gets down to the. 3 or 30% range, the leg is at risk for developing gangrene.
Another recent test is called biphasic Doppler examination. This test allows for separation and quantification of abnormal blood flow. A sound wave is bounced off the blood in your arteries and the tracing produced can help determine the extent of peripheral vascular disease. Generally accepted criteria of disease are: (i) reduction of the height of the wave of blood traveling down the artery, (ii) absence of a reversal of the wave between heart beats and (iii) a rounded peak of the wave on the tracing. Other more subtle signs which can be read by the physician to help with the diagnosis include velocity tracings and evaluation of the frequency of the signal at different levels of the artery.
The application of segmental plethymography and pulse volume recordings have added additional information to the peripheral vascular work-up. In this test, blood pressure cuffs are applied to the legs at different levels and the machine measures small volume changes in the diameter of the leg with each heart beat. The bigger the volume change, the better the blood flow is in that part of the leg. If the measurements of each segment of the leg are compared, five different degrees of severity of disease can be determined and a suspected blockage can be localized to an area of the leg. This test also works on veins and even small changes in the blood flow to the skin can be measured.
Patients with cold fingers even on warm days may have vasospastic disease in the small arteries of the fingers. This condition is called Raynaud’s disease and is found in many women with otherwise normal larger arteries. Using digital plethymography, an increased resistance to blood flow due to spasm in the artery can be measured and the patient treated with medication to dilate the artery and increase the blood flow to the fingers.
If you have cold fingers or feet the problem may be vasospastic disease. Talk to your physician about a peripheral vascular testing program or noninvasive work-up.
If your legs hurt when you walk to the mail box and back, problems can be excluded and then you may benefit from a work-up. Both balloon angioplasty to open the area of stenosis without surgery and bypass surgery can be used to improve the blood flow and stop the pain.
If you have rest pain at night, talk to your doctor this week to make sure you don’t have total occlusion of the arteries in your legs. Finally, if it hurts, get someone to look at you. Don’t wait until the last resort is to remove the leg.