Abstract 312: Anatomic Runoff Score Predicts Cardiovascular Outcomes in Patients with Lower Extremity Peripheral Artery Disease

Background: Although the presence, extent, and severity of obstruction in patients with lower extremity peripheral artery disease (LE-PAD) affect their clinical care, it is not known if these factors are associated with future cardiovascular endpoints. We empirically created an anatomic runoff score (ARS) that was based on the severity of stenosis of each lower extremity segment, and determined its association with clinical outcomes. Methods: We evaluated 908 patients with LE-PAD and bilateral angiography undergoing endovascular or surgical revascularization in a community based clinical study from 2005-2011. Clinical outcomes of interest were 1) all-cause death, 2) myocardial infarction (MI), 3) stroke, and 4) composite of all-cause death, MI, and stroke. Cox proportional hazards models were created and hazard ratios estimated for a standard deviation increment for continuous variables. Results: A total of 260 patients reached the composite endpoint (45 MI, 63 stroke, 152 death) during the study period. ARS ranged from 0-15 [Mean 4.7 (SD 2.5), Figure]. Patients who experienced the composite endpoint were more likely to be older, have more co-morbid conditions, were more likely to have undergone revascularization for CLI, and had a higher ARS (indicating more extensive PAD). The most significant predictors of the composite endpoint (death/MI/stroke) were age (delta=10 years; HR 1.40, CI 1.25-1.55, p<0.0001), diabetes mellitus (HR 1.51, CI 1.16-1.98, p=0.0026), ARS (delta=2 points; HR 1.15, CI 1.03-1.26, p=0.0187), and indication for procedure (CLI vs. claudication; HR 1.68, CI 1.28-2.21, p=0.0002). The use of the ARS to predict the composite outcome was comparable for patients with CLI and patients with claudication (in patients with CLI, ARS HR=1.15; in patients with Claudication, ARS HR=1.21; interaction p value=0.70). Conclusions: After adjustment for clinical factors, the LE-PAD anatomic runoff score, age and indication for procedure were the most significant predictors of future cardiovascular morbidity and mortality in a broadly-representative patient population undergoing revascularization for symptomatic PAD. The use of a clinically useful anatomic scoring system, if validated, may assist clinicians in risk-stratifying patients during the course of clinical decision-making.