The Lower Extremity Grading System
An objective scoring method may help interventionalists select the optimal treatment for patients with peripheral arterial disease.
Peripheral arterial disease of the lower extremities is a prevalent problem in the elderly population. Coexistent cardiac and cerebrovascular disease carries a 5-year mortality rate of 50% in patients with intermittent claudication (IC), and a mortality rate of 60% to 70% in patients with critical limb ischemia (CLI).1 Lower extremity revascularization is considered for a minority of these patients (~25%). Available treatments differ vastly and include primary amputation, open bypass surgery, percutaneous endovascular therapy, and/or risk factor modification with exercise. The heterogeneity of patient comorbidities, extent of arterial disease, ambulatory status, and level of ischemia makes endpoint analysis of revascularization difficult across this broad range of treatments. Traditional outcome assessment focuses on amputation-free survival for patients with CLI or walking distance in patients with IC, with patency (primary, primary-assisted, or secondary) indicating the “best” option. These outcome measures do not account for functional status and quality of life, nor do they take into account the limited life expectancy often seen in patients with CLI.
ANALYZE AMBULATORY STATUS
The available literature shows excellent revascularization results using traditional outcomes; unfortunately, quality of life and functional status remain the same. Gibbons et al reported the functional outcome of patients undergoing traditional bypass surgery.2 Bypass primary patency was 95% at 6 months; however, only 47% of patients returned to normal activity levels at 6 months, and there was a 10% increase in the need to use a walker for assistance. Similarly, Porter et al evaluated the ambulatory status in 513 patients who underwent lower extremity revascularization.3 These investigators noted no change in 96% of patients after revascularization, implying that if patients did not walk much before the procedure, they probably would not change their behavior afterward. Whyman et al reported the results of PTA for short SFA (75%) or iliac (25%) stenoses, or occlusions on 62 patients.4 Despite improvement in the ankle:brachial index and duplex ultrasound in the PTA group, there was no increase in walking at 2 year follow-up. This point raises the following questions:
• Should we revascularize these patients at all?
• If revascularization is warranted, which procedure is appropriate?
• Do we need to study different outcome measures such as ambulatory status, independent living status, and quality of life?
ASSESS FUNCTIONAL STATUS
To answer the previously mentioned questions, we must first assess the functional status of the patient prior to treatment, and then standardize the use of revascularization. The Lower Extremity Grading Scale (LEGS) scoring system is an attempt at standardization (Table 1) Please refer to the print version of our November/December issue, page 16, to view this table.
Prior to LEGS evaluation, patients must be considered surgical candidates and endovascular treatment must be an option, regardless of the extent of the anatomic lesion. The physician calculates a patient’s initial, overall score based on the complexity of the lesion, the degree of ischemia, the baseline function level, the presence of medical comorbidities, and other technical features that negatively impact either a surgical or endovascular option. If a patient’s cumulative score equals 0 to 9 points, the physician recommends open surgical repair. A score of 10 to 19 points indicates endovascular treatment is possible; primary amputation is an option for patients with greater than 20 points.
The anatomic lesion is scored using the Transatlantic Inter-Society Consensus (TASC) classification.5 This classification grades complexity based on the length of the lesion, location, and the presence of an occlusion. An anatomic score is given for aortoiliac disease as well as infrainguinal disease because treatment alternatives are usually sequential rather than concomitant. The points assigned for lesions decrease as the severity of disease increases. Simple lesions rate 8 points and complex lesions rate 0 points. The presenting symptoms are also stratified, with intermittent claudication patients given 5 points and CLI patients given 2 points. This approach accounts for the inherent belief that CLI is usually due to multilevel disease, and balloon angioplasty does not provide as much volume flow or extended patency as bypass surgery.
Finally, functional status is considered in order to identify those patients who are active versus those who are nonactive despite their symptoms. Ambulatory status can include independent/outside or restricted/indoors, whereas nonambulatory status designates wheelchair-bound or bedridden patients. Cardiovascular morbidity and mortality escalates as functional status declines. This LEGS scoring category takes into account that a “couch potato” will not have the same life expectancy or functional status as an avid golfer who suffers from IC. Medical comorbidities, including morbid obesity, cardiac dysfunction, and age are clinically relevant and impact decision-making. Morbid obesity is assessed according to a standardized nomogram. The Eagle criteria scale is used to determine the level of cardiovascular risk; only patients with high scores are given points.
THE SCORING SYSTEM
When calculating a patient’s score, the physician must take into account technical factors that could negatively impact the presumed success of a procedure (Figure 1). Failed prior bypass surgery portends higher risk and reduced chance of success, particularly if no autologous vein is available. Bypass to an isolated segment is avoided, as are patients with active infection or gangrene (Figure 2).
After determining the patient’s score, the physician proceeds with the best procedure, whether it happens to be open or endovascular. Patients are followed with objective measures (ABI, duplex ultrasound), and SF 36 functional status and quality-of-life surveys. Follow-up continues throughout the patient’s lifetime.
EVALUATE TREATMENT OPTIONS
After the interventionalist obtains clinical correlation of the score, randomization between treatment options can be studied. Patients who have similar risks and baseline characteristics can be evaluated together, thus limiting the heterogeneity of study populations. For instance, patients with a cumulative score of 8 to 9 points could be randomized between open surgical repair and endovascular therapy; patients with a score of 15 to 17 could be randomized between stand-alone angioplasty versus angioplasty plus stenting. This approach may minimize ambiguity of study subjects while comparing different treatment options for patients with symptomatic lower extremity peripheral arterial disease.
Modern endovascular techniques that enable application to any anatomic or patient problem make such a scoring system possible—and necessary. Treatment decisions are currently made with subjective rather than objective functional end points. Adding objectivity to the treatment algorithm can only improve with standardization of patients and procedures. A patient’s LEGS score has yet to be proven as a tool for making treatment decisions. My colleagues and I eagerly await the results of our clinical correlation and early outcomes data at our institution in Greenville, South Carolina.
Bruce H. Gray, DO, is Director of Endovascular Surgery in the Academic Department of Surgery at Greenville Memorial Hospital System in Greenville, South Carolina. Dr. Gray may be reached at (864) 455-7886; firstname.lastname@example.org.
Spence Taylor, MD, is Chairman of the Academic Department of Surgery at Greenville Memorial Hospital System in Greenville, South Carolina. Dr. Taylor may be reached at (864) 455-7886.
Corey Kalbaugh, BS, is a graduate student in the Department of Biomedical Engineering at Clemson University in Clemson, South Carolina. Mr. Kalbaugh may be reached at (864) 455-7886; email@example.com.
1. McDaniel MD, Cronenwett JL. Basic data related to the natural history of intermittent claudication. Ann Vasc Surg. 1989;3:273-277.
2. Gibbons GW, Burgess AM, Guadagnoli E, et al. Return to well being and function after infrainguinal revascularization. J Vasc Surg. 1995;21:35-45.
3. Abou-Zamzam AM, Lee RW, Moneta GL, et al. Functional outcome after infrainguinal bypass for limb salvage. J Vasc Surg. 1997;25:287-297.
4. Whyman MR, Fowkes FG, Kerracher EM, et al. Is intermittent claudication improved by percutaneous transluminal angioplasty? A randomized controlled trial. J Vasc Surg. 1997;26:551-557.
5. Management of peripheral arterial disease (PAD). TASC Working Group. Transatlantic Inter-Society Consensus (TASC). J Vasc Surg. 2000;(suppl 1):S1-S296.
6. Eagle KA, Berger PB, Calkins H, et al. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery: Executive summary of a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery. Circ J Am Heart Assoc. 2002;105:1257-1267.