Despite advancements, aortofemoral bypass (AFB) remains the most durable option for aortoiliac occlusive disease. While runoff has been shown to be associated with AFB patency, the Society of Vascular Surgery (SVS) thigh runoff scoring system’s association with patency has not been assessed. The aim of this study is to evaluate the association between the SVS runoff scoring system and limb-based primary patency after AFB.
Institutional data for patients undergoing aortofemoral bypass with preoperative runoff imaging from 2000-2017 were queried. Runoff scores were assigned based on occlusive disease in the SFA and profunda femoris artery (minimum 1 and maximum 10) as described by the 1997 SVS reporting standards on lower extremity ischemia. Limb-based patency was the primary endpoint. Kaplan-Meier analysis was used to compare long-term limb-based patency and freedom from reintervention between limbs with runoff scores ≥ 6 to limbs with runoff scores<6. Propensity score-weight Cox-proportional hazards modeling was used to evaluate for association between runoff score ≥ 6 and primary patency loss while controlling for other factors associated with primary patency.
In 161 patients, 316 limbs were revascularized. Mean age was 66.7±11.3 years; 51.6% were women. The majority were revascularized for claudication (56.5%). Most (89.4%) had TASC D lesions, 27.3% required suprarenal clamp or higher, and 11.2% underwent concomitant mesenteric intervention. Femoral outflow adjunct and concurrent lower extremity bypass were required in 41.8% and 2.9% of limbs, respectively. Those with runoff scores ≥ 6 had higher rates of 30-day myocardial infarction (11% vs 1%; p=.005), respiratory failure (11% vs 1%; p=.005), and mortality (8% vs 0%; p≤.006). Median follow-up was 4.0 years (IQR:6.5 years). One, three, and five-year primary patency was 94.6% (95%CI:91.9%-97.3%), 89.2% (95% CI:85.4%-93.2%), and 81.4% (95%CI:76.0%-87.1%), respectively. Five-year primary-assisted patency, secondary patency, and freedom-from-reintervention were 84.9% (95%CI: 79.7%-90.5%), 91.7% (95%CI: 87.3%-96.3%), and 83.3% (95%CI:78.3%-88.7%), respectively. Patients with runoff scores ≥6 had lower primary (log rank, p<0.01), primary-assisted (p<0.01), and secondary patency (p=0.01). Factors associated with loss of primary-patency included high runoff score (runoff score ≥6 HR: 4.1; 95% CI: 2.1-8.0; p<.01), simultaneous mesenteric endarterectomy (HR 13.5; 95% CI: 1.9-97.8; p=0.01) and CKD (HR 4.6; 95% CI: 1.5-14.6; p=0.01). Increasing age (HR 0.94 per year; 95% CI: 0.91-0.97; p<0.01) and hyperlipidemia (HR 0.44; 95% CL: .23-.85; p=0.01) were protective.
SVS femoral runoff scoring is an important factor associated with long-term AFB limb patency. Scores ≥6 portend worse limb outcomes and operative complications. This score can be determined from preoperative axial imaging and serve as a guide in decision making and operative planning.