Critical analysis of clinical success after surgical bypass for lower-extremity ischemic tissue loss using a standardized definition combining multiple parameters: a new paradigm of outcomes assessment.

Abstract

Success after surgical revascularization of the lower extremities, traditionally defined by graft patency or limb salvage, fails to consider other intuitive measures of importance. The purpose of the study was to construct a more comprehensive definition of clinical success and to identify clinical predictors of failure. For the purpose of this study, clinical success was defined as achieving all of the following criteria: graft patency to the point of wound healing; limb salvage for 1 year; maintenance of ambulatory status for 1 year; and survival for 6 months. Between 1998 and 2004, 331 consecutive patients undergoing bypass for Rutherford III critical limb ischemia were measured for clinical success. Bivariate and logistic regression analyses were performed to determine demographic differences between success and failure. Despite achieving acceptable graft patency (72.7% at 36 months) and limb salvage (73.3% at 36 months), clinical success combining all 4 defined parameters was only 44.4%. Independent predictors of failure included impaired ambulatory status at presentation (odds ratio [OR] = 6.44), presence of infrainguinal disease (OR = 3.93), end-stage renal disease (OR = 2.48), presence of gangrene (OR = 2.40), and hyperlipidemia (OR = 0.56). Probability of failure in patients possessing every predictor except hyperlipidemia at presentation was 97% (OR = 150.6). Despite achieving acceptable graft patency and limb salvage, fewer than half of the patients achieved success when using a definition combining multiple parameters. A reappraisal of our current approach to critical limb ischemia in certain high-risk patients is warranted.