A comparative evaluation of risk-adjustment models for benchmarking amputation-free survival after lower extremity bypass

Abstract

Background Providing patients and payers with publicly reported risk-adjusted quality metrics for the purpose of benchmarking physicians and institutions has become a national priority. Several prediction models have been developed to estimate outcomes after lower extremity revascularization for critical limb ischemia, but the optimal model to use in contemporary practice has not been defined. We sought to identify the highest-performing risk-adjustment model for amputation-free survival (AFS) at 1 year after lower extremity bypass (LEB). Methods We used the national Society for Vascular Surgery Vascular Quality Initiative (VQI) database (2003–2012) to assess the performance of three previously validated risk-adjustment models for AFS. The Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL), Finland National Vascular (FINNVASC) registry, and the modified Project of Ex-vivo vein graft Engineering via Transfection III (PREVENT III [mPIII]) risk scores were applied to the VQI cohort. A novel model for 1-year AFS was also derived using the VQI data set and externally validated using the PIII data set. The relative discrimination (Harrell c-index) and calibration (Hosmer-May goodness-of-fit test) of each model were compared. Results Among 7754 patients in the VQI who underwent LEB for critical limb ischemia, the AFS was 74% at 1 year. Each of the previously published models for AFS demonstrated similar discriminative performance: c-indices for BASIL, FINNVASC, mPIII were 0.66, 0.60, and 0.64, respectively. The novel VQI-derived model had improved discriminative ability with a c-index of 0.71 and appropriate generalizability on external validation with a c-index of 0.68. The model was well calibrated in both the VQI and PIII data sets (goodness of fit P = not significant). Conclusions Currently available prediction models for AFS after LEB perform modestly when applied to national contemporary VQI data. Moreover, the performance of each model was inferior to that of the novel VQI-derived model. Because the importance of risk-adjusted outcome reporting continues to increase, national registries such as VQI should begin using this novel model for benchmarking quality of care.

Barthel Index and Outcome of Open Bypass for Critical Limb Ischemia

“…Since the BASIL trial demonstrated the superiority of the bypass-first strategy in patients with a life expectancy >2 years, 1 many studies have identified a variety of factors as predictors of long-term outcome of revascularization for CLI, 2-6 and several scoring systems with risk stratification and confirmed validity regarding the prediction of outcomes have been introduced. [5][6][7][8] Activities of daily living (ADL) or physical function should be considered when determining the treatment strategy because patients with poor ADL often have significant comorbidities, and there is little expectation of improvement in their ADL or physical function even after revascularization. 9 Some studies have reported an association between the physical activity or functional status and mortality in patients with PAD.…”

Evaluation of paramalleolar and inframalleolar bypasses in dialysis- and nondialysis-dependent patients with critical limb ischemia

“…Current reports of distal bypass outcomes from leading vascular centers have demonstrated no differences in graft patency, survival, and LS rates between DM and non-DM patients. [31][32][33][34] These excellent outcomes have been reported to be attributable not only to exquisite bypass surgery techniques but also to careful postoperative management of wound infection, strict graft surveillance and revision surgery, and appropriate management of cardiac diseases. Such techniques and management strategies may be effective and essential in HD DM patients; however, in HD DM patients, ischemic gangrene is commonly associated with infection and advanced occlusive lesions and calcification involving peripheral small-caliber arteries.…”

“…14 Nonambulation has been found to be associated with poor survival 14,35 and AFS rates in HD and NHD patients. 19,35,37 Simons et al 31 reported a 1-year AFS rate of 74% after lower limb bypass, and poor ambulatory status and HD were the most relevant factors associated with it, whereas retrieval of ambulation was associated with improved survival rates. 35 Likewise, the results of this study demonstrated that ambulation after bypass and CHF significantly influenced survival rates in HD patients, and approximately half of the deaths occurring between 30 days and 5 years after LS were caused by cardiac events.…”

Outcomes of Lower Extremity Endovascular Revascularization: Potential Predictors and Prevention Strategies

“…They include advanced age (over 75 or 80 years), CAD, congestive heart failure, diabetes mellitus (DM), chronic kidney disease (CKD), smoking, cerebrovascular disease, tissue loss, body max index (BMI), dementia, functional status, and frailty. In recent years, multiple risk stratification tools have been retrospectively developed for patients who underwent surgical revascularization [ 3 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ], but none has been tested prospectively and endorsed by international guidelines.…”