Does a standardization tool to direct invasive therapy for symptomatic lower extremity peripheral arterial disease improve outcomes? Discussion

While decision analysis and treatment algorithms have repeatedly been shown to improve quality of care in many areas of medicine, no such algorithm has emerged for the invasive management of lower extremity peripheral arterial disease. Using the best available evidence-based outcomes data, our group designed a standardization tool, the Lower Extremity Grading System (LEGS) score, which consistently directs limbs to a specific treatment on the basis of presentation. The purpose of this study was to examine whether use of such a tool improves outcomes by directing treatment of lower extremity peripheral arterial disease. Over 18 months (July 2001-December 2002) our group intervened in 673 limbs (angioplasty, open surgery, primary limb amputation) with lower extremity peripheral arterial disease. During this time we developed the LEGS score, and implemented its prospective use for the final 362 limbs. For the purpose of this study, all 673 limbs were retrospectively scored with the LEGS score to determine the LEGS recommended best treatment. Of the 673 limbs, 551 (81.9%) received the same treatment as recommended with LEGS and 122 (18.1%) received treatment contrary to LEGS. Limbs treated contrary to LEGS (cases) were then compared with matched control limbs (treated according to LEGS), with similar angiographic findings, clinical presentation, preoperative functional status, comorbid conditions and operative technical factors. Outcomes measured at 6 months included arterial reconstruction patency, limb salvage, survival, and maintenance of ambulatory status and independent living status. Kaplan-Meier curves were used to assess patency, limb salvage, and survival; associated survival curves were compared with the log-rank test. Functional outcomes were compared with the Fisher exact test. After matching case limbs with control limbs, 9 limbs had no control match. Thus 113 limbs in 100 patients treated contrary to LEGS were compared with 113 limbs in 100 patients treated according to LEGS. Limbs treated contrary to LEGS resulted in significantly inferior outcomes at 6 months for measures of primary patency (57.5% vs 84.3%; P <. 001), secondary patency (73.2% vs 96.2%; P <. 001), limb salvage (89.7% vs 97.2%; P =. 04), and maintenance of ambulatory status (78% vs 92%; P =. 02). As an additional finding, 29.6% (92 of 311) of interventions performed before implementation of the algorithm were treated contrary to LEGS, and thus contrary to objectively determined best therapy, compared with 8.3% (30 of 362) after LEGS implementation (P <. 001). Limbs treated according to our standardization tool resulted in better outcomes compared with limbs treated contrary to the algorithm. These data suggest that routine use of an appropriately validated treatment standardization algorithm is capable of improving overall results for invasive treatment of lower extremity peripheral arterial disease.