Ankle–brachial pressure index | |
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Synonyms | Ankle-brachial index |
Purpose | Detection of peripheral artery disease |
The ankle-brachial pressure index (ABPI) or ankle-brachial index (ABI) is the ratio of the blood pressure at the ankle to the blood pressure in the upper arm (brachium). Compared to the arm, lower blood pressure in the leg suggests blocked arteries due to peripheral artery disease (PAD). The ABPI is calculated by dividing the systolic blood pressure at the ankle by the systolic blood pressure in the arm. [1]
The patient must be placed supine, without the head or any extremities dangling over the edge of the table. Measurement of ankle blood pressures in a seated position will grossly overestimate the ABI (by approximately 0.3).[ citation needed ]
A Doppler ultrasound blood flow detector, commonly called Doppler wand or Doppler probe, and a sphygmomanometer (blood pressure cuff) are usually needed. The blood pressure cuff is inflated proximal to the artery in question. Measured by the Doppler wand, the inflation continues until the pulse in the artery ceases. The blood pressure cuff is then slowly deflated. When the artery's pulse is re-detected through the Doppler probe the pressure in the cuff at that moment indicates the systolic pressure of that artery.[ citation needed ] The higher systolic reading of the left and right arm brachial artery is generally used in the assessment. The pressures in each foot's posterior tibial artery and dorsalis pedis artery are measured with the higher of the two values used as the ABI for that leg. [2]
The ABPI test is a popular tool for the non-invasive assessment of Peripheral vascular disease (PVD). Studies have shown the sensitivity of ABPI is 90% with a corresponding 98% specificity for detecting hemodynamically significant (stenosis of more than 50%) in major leg arteries, defined by angiogram. [3]
However, ABPI has known issues:
When performed in an accredited diagnostic laboratory, the ABI is a fast, accurate, and painless exam, however these issues have rendered ABI unpopular in primary care offices and symptomatic patients are often referred to specialty clinics [13] due to the perceived difficulties. Technology is emerging that allows for the oscillometric calculation of ABI, in which simultaneous readings of blood pressure at the levels of the ankle and upper arm are taken using specially calibrated oscillometric machines.[ citation needed ]
In a normal subject the pressure at the ankle is slightly higher than at the elbow (there is reflection of the pulse pressure from the vascular bed of the feet, whereas at the elbow the artery continues on some distance to the wrist).[ citation needed ]
The ABPI is the ratio of the highest ankle to brachial artery pressure. An ABPI between and including 0.90 and 1.29 considered normal (free from significant PAD), while a lesser than 0.9 indicates arterial disease. [14] An ABPI value of 1.3 or greater is also considered abnormal, and suggests calcification of the walls of the arteries and incompressible vessels, reflecting severe peripheral vascular disease.[ citation needed ]
Provided that there are no other significant conditions affecting the arteries of the leg, the following ABPI ratios can be used to predict the severity of PAD as well as assess the nature and best management of various types of leg ulcers. [2] Studies also indicate that the assessment of PAD in people with diabetes should use both ABPI ratios and Doppler waveforms. [15]
ABPI value | Interpretation | Action | Nature of ulcers, if present |
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1.3 and above | Abnormal Vessel hardening from PVD | Refer or measure Toe pressure | Venous ulcer use full compression bandaging |
1.0 - 1.2 | Normal range | None | |
0.90 - 0.99 | Acceptable | ||
0.80 - 0.89 | Some arterial disease | Manage risk factors | |
0.50 - 0.79 | Moderate arterial disease | Routine specialist referral | Mixed ulcers use reduced compression bandaging |
under 0.50 | Severe arterial disease | Urgent specialist referral | Arterial ulcer no compression bandaging used |
Studies in 2006 suggests that an abnormal ABPI may be an independent predictor of mortality, as it reflects the burden of atherosclerosis. [16] [17] It thus has potential for screening for coronary artery disease, [18] although no evidence-based recommendations can be made about screening in low-risk patients because clinical trials are lacking. [18] It is noteworthy that abnormal values of ABI predispose to development of the frailty syndrome. [19]
In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the neck, wrist, at the groin, behind the knee, near the ankle joint, and on foot. The radial pulse is commonly measured using three fingers. This has a reason: the finger closest to the heart is used to occlude the pulse pressure, the middle finger is used get a crude estimate of the blood pressure, and the finger most distal to the heart is used to nullify the effect of the ulnar pulse as the two arteries are connected via the palmar arches. The study of the pulse is known as sphygmology.
The femoral artery is a large artery in the thigh and the main arterial supply to the thigh and leg. The femoral artery gives off the deep femoral artery and descends along the anteromedial part of the thigh in the femoral triangle. It enters and passes through the adductor canal, and becomes the popliteal artery as it passes through the adductor hiatus in the adductor magnus near the junction of the middle and distal thirds of the thigh.
Peripheral artery disease (PAD) is a vascular disorder that causes abnormal narrowing of arteries other than those that supply the heart or brain. PAD can happen in any blood vessel, but it is more common in the legs than the arms.
Vascular surgery is a surgical subspecialty in which vascular diseases involving the arteries, veins, or lymphatic vessels, are managed by medical therapy, minimally-invasive catheter procedures and surgical reconstruction. The specialty evolved from general and cardiovascular surgery where it refined the management of just the vessels, no longer treating the heart or other organs. Modern vascular surgery includes open surgery techniques, endovascular techniques and medical management of vascular diseases - unlike the parent specialities. The vascular surgeon is trained in the diagnosis and management of diseases affecting all parts of the vascular system excluding the coronaries and intracranial vasculature. Vascular surgeons also are called to assist other physicians to carry out surgery near vessels, or to salvage vascular injuries that include hemorrhage control, dissection, occlusion or simply for safe exposure of vascular structures.
In medicine, aortoiliac occlusive disease is a form of central artery disease involving the blockage of the abdominal aorta as it transitions into the common iliac arteries.
Intermittent claudication, also known as vascular claudication, is a symptom that describes muscle pain on mild exertion, classically in the calf muscle, which occurs during exercise, such as walking, and is relieved by a short period of rest. It is classically associated with early-stage peripheral artery disease, and can progress to critical limb ischemia unless treated or risk factors are modified and maintained.
Claudication is a medical term usually referring to impairment in walking, or pain, discomfort, numbness, or tiredness in the legs that occurs during walking or standing and is relieved by rest. The perceived level of pain from claudication can be mild to extremely severe. Claudication is most common in the calves but it can also affect the feet, thighs, hips, buttocks, or arms. The word claudication comes from Latin claudicare 'to limp'.
A peripheral vascular examination is a medical examination to discover signs of pathology in the peripheral vascular system. It is performed as part of a physical examination, or when a patient presents with leg pain suggestive of a cardiovascular pathology.
May–Thurner syndrome (MTS), also known as the iliac vein compression syndrome, is a condition in which compression of the common venous outflow tract of the left lower extremity may cause discomfort, swelling, pain or iliofemoral deep vein thrombosis.
Compression stockings are a specialized hosiery designed to help prevent the occurrence of, and guard against further progression of, venous disorders such as edema, phlebitis and thrombosis. Compression stockings are elastic compression garments worn around the leg, compressing the limb. This reduces the diameter of distended veins and increases venous blood flow velocity and valve effectiveness. Compression therapy helps decrease venous pressure, prevents venous stasis and impairments of venous walls, and relieves heavy and aching legs.
Mönckeberg's arteriosclerosis, or Mönckeberg's sclerosis, is a non-inflammatory form of arteriosclerosis or vessel hardening, which differs from atherosclerosis traditionally. Calcium deposits are found in the muscular middle layer of the walls of arteries with no obstruction of the lumen. It is an example of dystrophic calcification. This condition occurs as an age-related degenerative process. However, it can occur in pseudoxanthoma elasticum and idiopathic arterial calcification of infancy as a pathological condition, as well. Its clinical significance and cause are not well understood and its relationship to atherosclerosis and other forms of vascular calcification are the subject of disagreement. Mönckeberg's arteriosclerosis is named after Johann Georg Mönckeberg, who first described it in 1903.
The term venous translucence has been used in phlebology since 1996 by surgeon Pedro Fernandes Neto during ambulatory clinical exams in Brazil. His results were published in the annals of the national and international congresses of angiology. Venous translucence is the process of reflective image visualization of veins by light, which reaches up to the superficial venous system. It is a non-invasive method. Since it is a simple, low-cost technique it can be repeated as needed, which is useful in disease-process monitoring. It is a new diagnostic procedure, still undergoing investigation; more analysis is necessary to hone its technical aspects. Venous translucence is based on optical physics. It is caused by the refraction, absorption and reflection of light. The color which is not absorbed is reflected, and is the one that is seen. Therefore, venous translumination is based on the incidence of luminosity on the vein, where part of the light is absorbed and another reflected.
Chronic venous insufficiency (CVI) is a medical condition in which blood pools in the veins, straining the walls of the vein. The most common cause of CVI is superficial venous reflux which is a treatable condition. As functional venous valves are required to provide for efficient blood return from the lower extremities, this condition typically affects the legs. If the impaired vein function causes significant symptoms, such as swelling and ulcer formation, it is referred to as chronic venous disease. It is sometimes called chronic peripheral venous insufficiency and should not be confused with post-thrombotic syndrome in which the deep veins have been damaged by previous deep vein thrombosis.
Arterial insufficiency ulcers are mostly located on the lateral surface of the ankle or the distal digits. They are commonly caused by peripheral artery disease (PAD).
Acute limb ischaemia (ALI) occurs when there is a sudden lack of blood flow to a limb, within 14 days of symptoms onset. It is different from another condition which is more chronic called critical limb ischemia (CLD). CLD is the end stage of peripheral vascular disease where there is still some collateral circulation (alternate circulation pathways} that bring some blood to the distal parts of the limbs. While limbs in both acute and chronic limb ischemia may be pulseless, a chronically ischemic limb is typically warm and pink due to a well-developed collateral artery network and does not need emergency intervention to avoid limb loss.
The cardiovascular examination is a portion of the physical examination that involves evaluation of the cardiovascular system. The exact contents of the examination will vary depending on the presenting complaint but a complete examination will involve the heart, lungs, belly and the blood vessels.
Doppler ultrasonography is medical ultrasonography that employs the Doppler effect to perform imaging of the movement of tissues and body fluids, and their relative velocity to the probe. By calculating the frequency shift of a particular sample volume, for example, flow in an artery or a jet of blood flow over a heart valve, its speed and direction can be determined and visualized.
Claude Franceschi is an angiologist French MD.
Chronic limb threatening ischemia (CLTI), also known as critical limb ischemia (CLI), is an advanced stage of peripheral artery disease (PAD). It is defined as ischemic rest pain, arterial insufficiency ulcers, and gangrene. The latter two conditions are jointly referred to as tissue loss, reflecting the development of surface damage to the limb tissue due to the most severe stage of ischemia. Compared to the other manifestation of PAD, intermittent claudication, CLI has a negative prognosis within a year after the initial diagnosis, with 1-year amputation rates of approximately 12% and mortality of 50% at 5 years and 70% at 10 years.
Blood pressure in toes can be measured using special equipment, and is often valuable in assessment of severe peripheral artery disease, in particular in patients with diabetes where measurement of ankle pressure / ABPI is often unreliable.