Best practice assessment for lower limbs with lymphedema
By Maryse Beaumier
Introduction
Lymphedema affects an estimated 35 million people in the United States and more than a staggering 140 million people worldwide, yet lymphedema is the forgotten vascular disease.1 Lymphatic, arterial and venous are the three vascular systems in the lower limb.1 All of them work together. The weakness of one can disturb the others, so it is essential to evaluate all of them before deciding on a treatment plan.
Each vascular problem in a lower limb has its unique treatment. Still, all the lower limbs require an assessment of the underlying arterial vascular condition before deciding on any compression or wound treatment.2,3 For example, compression of 40-45 mmHg
TABLE 1
Assessing Arterial Flow and Perfusion
is necessary to treat a wound when a venous deficiency is present. For lower limb lymphedema, a higher compression of up to 60-90 mmHg may be required.34 Finally, with severe arterial insufficiency (chronic limbthreatening ischemia), compression may not be safe. Chronic limb-threatening ischemia (CLTI) is a condition characterized by chronic ischemic rest pain presenting for >2 weeks, non-healing ulcers and/or gangrene in one or both lower extremities in conjunction with a clear diagnosis of peripheral arterial disease (PAD).19 Thus, persons with CLTI should always be assessed for the level of risk for amputation.35 The arterial status is the most critical step to assess a lower limb before deciding on treatment for a lymphatic or venous leg.
Complication of bandaging applied too tightly.
Source: M.Beaumier
As per the International Consensus for Best Practice for the Management of Lymphoedema, the arterial vascular status of the legs of all patients with lower limb lymphedema should be assessed before choosing the appropriate compression level.4,5 This article will present three non-invasive ways to assess the arterial status of the legs: the Ankle-Brachial Index (ABI), toe pressure measurement, and waveform interpretation.
Assessment
Source: Beaumier, M., Murray, B. A., Despatis, M.-A., Patry, J., Murphy, C., Jin, S., & O’Sullivan-Drombolis, D. (2020). Best Practice Recommendations for the Prevention and Management of Peripheral Arterial Ulcers. In: Foundations of Best Practice for Skin and Wound Management. A supplement of Wound Care Canada.
Maryse Beaumier BScN, MSc, PhD is a Professor in the Department of Health at the Université du Québec, Board Member of the Canadian Lymphedema Framework, Scientific Director and Researcher at the CISSS ChaudièreAppalaches Research Center, and author of Best Practice Recommendations for the Prevention and Management of Peripheral Arterial Ulcers.
Assessment of the arterial vascular condition means detecting the presence of peripheral arterial disease in the lower limbs. Peripheral arterial disease (PAD) is a chronic disease that can affect the upper and lower extremities but occurs more frequently in the lower extremities. The presence of PAD may contraindicate compression therapy or require a reduced level of compression.6 PAD causes decreased blood and oxygen supply to the skin, constituting ischemia that can affect any healing process. PAD leading to stenosis or occlusion of arteries supplying the lower limbs is caused by atherosclerosis in approximately 95% of cases.7 Clinical assessment is a central component of evaluation.8 About 200 million people worldwide are estimated to experience lower extremity peripheral artery disease.9 Peripheral artery disease is becoming an increasingly serious public health problem.10 A meta-analysis reported a 23.5% increase in PAD prevalence during the first decade of the new millennium.11 With the demographic trend towards aging and the projected rise in important risk factors, a more significant burden of peripheral artery disease is to be expected in the foreseeable future.10 The clinical presentation of patients
with objectively confirmed PAD can be categorized into four clinical subsets: asymptomatic PAD, chronic symptomatic PAD, chronic limb-threatening ischemia (CLTI),
smoking, dyslipidemia, hypertension, sedentarity, obesity and alcohol excess.3 The history story and physical examination are essential to identify patients with PAD or at increased risk of PAD; to assess for lower extremity symptoms, assess for pulse deficits, and other signs of PAD, including lower
Ankle-brachial pressure index
The ankle-brachial pressure index (ABPI) is also commonly known as ankle-brachial index (ABI).
It is a simple, non-invasive physiological test that remains the cornerstone for the initial diagnosis of PAD. Peripheral artery disease, defined as an ankle-brachial index lower than or equal to 0.90, is a major cardiovascular disease worldwide10 The values are well described in Table 1. However, this measure has multiple limitations, particularly in the setting of diabetes and chronic kidney disease (CKD), which are associated with noncompressible vessels, and for the assessment of CLTI.12,13 The validity
FIGURE 1
Ankle-brachial Pressure Index
Source: M.Beaumier
Toe pressure assessment
of this test is known to be suboptimal in the presence of medial wall calcification of the main arteries, especially in the diabetic population, where it has been reported to be prevalent close to 19%.14,15 A literature review recognized a high specificity level for PAD (83.3-99.00%) for an ABPI ≤ 0.90 but sensitivity levels of 15 to 79% for ABPI > 0.90, with lower sensitivity in the elderly and people with diabetes.18 ABPI must be minimally accompanied by waveform sounds and/or toe pressure assessment. According to global vascular guidelines on the management of chronic limb-threatening ischemia, noncompressible arteries may lead to falsely elevated or false normal ABPI values in patients with diabetes, chronic renal insufficiency, or advanced age, thus leading to inconclusive, distorted results or potentially
The arterial vascular status assessment: an essential part of lower limb lymphedema treatment.
overestimating the actual vascular flow.16 Ankle-brachial pressure index (ABPI) objectively measures the patency of the large arteries supplying blood to the foot. It is calculated from the ratio of the highest ankle systolic pressure for each limb to the highest systolic pressure in the arm. There are limitations to the test, particularly in the presence of lymphedema. Tissue thickening, hyperkeratosis or edema may make it difficult to detect blood flow using the standard 8MHz probe. Using a 4MHz probe and a larger blood pressure cuff may overcome these problems.17
Clinical guidelines recommendations, such as Trans-Atlantic Inter-Society Consensus (TASCII), recommend using toe pressure measurement in addition to the ABPI and transcutaneous oximetry for diagnosing PAD and CLTI.19 However, anecdotal evidence exists that lymphedema practitioners do not use doppler in assessing lymphedema patients because there is doubt over the sensitivity and accuracy of results in edematous limbs. However, there is no empirical evidence relating to the sensitivity and accuracy of doppler on oedematous limbs.20,21 Researchers and practitioners have an opportunity to collaborate on this important missing piece of clinical evidence. The arteries of the big toes are less prone to calcification. Hence, measuring pressure
vascularization.19 Their psychometric properties show a sensitivity of 50.0% specificity of 73.1% for the pedal artery and sensitivity of 72.5%, and specificity of 91.3% for the posterior tibial artery. The posterior tibial pulse is known to be the best predictor of arterial status, but in more recent studies, the pedal pulse was two times the best predictor of arterial status. Three waveforms are possible: triphasic for healthy arteries, biphasic for the presence of light or moderate PAD, and monophasic for severe PAD.
Table 1 from Best Practice Recommendations for the Prevention and Management of Peripheral Arterial Ulcers (Best Practice— Wounds Canada) summarizes the results from ABPI, toe pressure, and waveforms for the arterial status assessment for PAD detection in the lower limbs.
Best Practice Recommendations for the Prevention and Management of Peripheral Arterial Ulcers. In: Foundations of Best Practice for Skin and Wound Management. A supplement of Wound Care Canada.
at the toe gives more accurate results with fewer false-positive values.7,22-25 Toe pressure is considered more sensitive than ABPI in diagnosing PAD.16,25-29 A sensitivity varying from 90 to 100% and a specificity ranging from 65 to 100% for detecting arterial stenosis have been reported.30 Toe pressure can be measured either by a manual procedure using plethysmography or with a laser doppler device. A correlation of 0.92 has been calculated about their results, so a manual device at the clinic is enough for the measure.31 Normal toe blood pressure values were between 70 - 100 mmHg, and values considered insufficient arterial blood supply were <30 mmHg or ≥ 100 mmHg.32,33
Waveforms interpretation
The waveforms (noise and graphic) of arterial waves detected when measuring systolic pressures in the pedal and posterior tibial arteries also make it possible to qualify the health of the arteries and help evaluate arterial
Conclusion
As mentioned in the International Consensus for Best Practice for Managing Lymphoedema, the arterial vascular status of the legs of all patients with lower limb lymphoedema should be assessed before choosing the appropriate compression level.
This article presents three principal non-invasive methods to assess the arterial status of the legs: the ankle-brachial pressure index (ABPI), the toe pressure measurement, and waveform interpretation. This step is mandatory before applying any compression of the lower limb of patients with lymphedema. LP
References can be found at https:// canadalymph.ca/pathways-references
FIGURE 3 Waveforms
Source: Beaumier, M., Murray, B. A., Despatis, M.-A., Patry, J., Murphy, C., Jin, S., & O’Sullivan-Drombolis, D. (2020).
FIGURE 2
Toe Pressure
Source: M. Beaumier