Results After Open and Endovascular Repair of Popliteal Aneurysm: A Matched Comparison Within a Population Based Cohort

Objective: To identify factors affecting the outcome after open surgical (OSR) and endovascular (ER) repair of popliteal artery aneurysm (PA) in comparable cohorts. Methods: A matched comparison in a national, population based cohort of 592 legs treated for PA (2008 - 2012), with long term follow up. Registry data from 899 PA patients treated in 2014 - 2018 were analysed for time trends. The 77 legs treated by ER were matched, by indication, with 154 legs treated with OSR. Medical records and imaging were collected. Analysed risk factors were anatomy, comorbidities, and medication. Elongation and angulations were examined in a core lab. The main outcome was occlusion. Results: Patients in the ER group were older (73 vs. 68 years, p = .001), had more lung disease (p = .012), and were treated with dual antiplatelet therapy or anticoagulants more often (p < .001). The hazard ratio (HR with 95% confidence intervals) for occlusion was 2.69 (1.60 - 4.55, p < .001) for ER, but 3.03 (1.26 - 7.27, p = .013) for poor outflow. For permanent occlusion, the HR after ER was 2.47 (1.35 - 4.50, p = .003), but 4.68 (1.89 - 11.62, p < .001) for poor outflow. In the ER subgroup, occlusion was more common after acute ischaemia (HR 2.94 [1.45 - 5.97], p = .003; and poor outflow HR 14.39 [3.46 - 59.92], p < .001). Larger stent graft diameter reduced the risk (HR 0.71 [0.54 - 0.93], p = .014). In Cox regression analysis adjusted for indication and stent graft diameter, elongation increased the risk (HR 1.020 per degree [1.002 - 1.033], p = .030). PAS treated for acute ischaemia had a median stent graft diameter of 6.5 mm, with those for elective procedures being 8 mm (p < .001). Indications and outcomes were similar during both time periods (2008 - 2012 and 2014 - 2018). Conclusion: In comparable groups, ER had a 2.7 fold increased risk of any occlusion, and 2.4 fold increased risk of permanent occlusion, despite more aggressive medical therapy. Risk factors associated with occlusion in ER were poor outflow, smaller stent graft diameter, acute ischaemia, and angulation/elongation. An association between indication, acute ischaemia, and small stent graft diameter was identified.