Predictive factors for better bypass patency and limb salvage after prosthetic above-knee bypass reconstruction

Peripheral arterial disease (PAD) is one of the most underestimated diseases because of its high prevalence and unfavorable prognosis. Many PAD patients without suitable autologous veins or options for endovascular treatment receive prosthetic above-knee femoropopliteal bypass (PAKB). Until now predictors of prosthetic bypass failure and of increased amputation risk remain indistinct. This study aimed to identify predictive factors associated with better bypass patency and limb salvage to achieve a more favorable outcome after PAKB reconstruction.

Pre-, intra-, and postoperative data of 244 PAKB procedures performed at a German university medical center were collected and analyzed using univariate and multivariate methods. To our knowledge this 12-year experience is the largest retrospective study to identify predictors for patency and limb salvage after PAKB reconstruction.

Of the PAD patients 94% (229/244) were followed for an average of 34.9 months. Patient cohorts characteristics were: mean age, 66.1 years, 181 men (74%), claudication (64%), rest pain (16%), ischemic lesions (20%), arterial hypertension (92%), smoking (79%), hyperlipidemia (65%) and type 2 diabetes (43%). Cumulative primary 1- and 3-year graft patency rates were 60.8% and 50.7%, respectively, and cumulative 1- and 3-year limb salvage rates were 89.3% and 86.1%, respectively. One hundred seven bypasses (43.9%) failed, 26 patients (10.7%) required a major and seven patients (2.9%) required a minor amputation. Overall survival rates of PAD patients after 1- and 3-years were 94.4% and 82.9%, respectively. Subjective symptom improvement was found to be the most important prognostic follow-up factor for graft patency and limb salvage. Patients with recurrent symptoms in the follow-up had an increased risk of emerging bypass failure compared with patients with subjective symptom improvement (patency at 1 year: 40.8% vs 100% and at 3 years: 26% vs 100%; P < .001). No patient with subjective improvement in symptoms during follow-up underwent an amputation (limb salvage at 1 year: 100% vs 79% and at 3 years: 100% vs 72.8%; P < .001). Therefore, subjective symptom improvement should be the decisive criterion to determine follow-up intervals of PAD patients. In univariate analysis further significant factors associated with better graft patency and limb salvage rates were: claudication compared with critical ischemia, larger graft diameter (>6 mm), pre- and postoperative antiplatelet therapy, statin therapy independent from lipid values after PAKB revascularization, and an experienced vascular surgeon.

In our study, we determined the subjective improvement in symptoms as the most important prognostic factor for bypass function and limb salvage after PAKB. Furthermore, disease stage of critical ischemia, graft diameter, preoperative aspirin use, and postoperative statin medication were independent predictive factors. Therefore, PAD patients should be treated with aspirin pre- and postoperatively as well as with a statin postoperatively. In case of PAKB reconstruction only prostheses with a large diameter (>6 mm) should be used and the procedure should be performed by an experienced surgeon. Considering these results with regard to the predictive factors for better graft patency and limb salvage rates a significant more favorable outcome during the follow-up and an increased 5-year patency rate for PAKB reconstructions can be expected.