Popliteal Artery Aneurysms : - epidemiology, treatment and results

Popliteal aneurysms (PA) are limb threatening, since the aneurysm thrombose and emboli from the aneurysm sac occlude the distal vessels, resulting in chronic or acute limb ischaemia. Open surgical repair (OSR) has been challenged by endovascular repair (ER), a minimal invasive technique. Little is known of long-term result, and comparisons of the methods have been difficult, since patients chosen for ER are mainly asymptomatic and have better outflow. The overall aim of this thesis was to study epidemiology and risk factors to optimize patient selection and techniques for surgical treatment of PA. Papers I and II: Data on all patients treated 2008-2012 (592 PAs in 499 patients) were analysed in the Swedish Vascular registry, Swedvasc. Patency was inferior after ER, in particular for patients with acute ischaemia. Nested in this cohort, a case-control study was performed, and the legs treated by ER (77) were matched, by indication, with twice the number treated with OSR (154). Medical records and radiologic images were collected and examined in a core-lab. In this matched cohort, the only independent risk factors for occlusion were ER and poor outflow. In a sub-group analysis of ER, risk factors for occlusion were acute ischaemia, poor out-flow, smaller stent graft diameter and elongation. Paper III: Prevalence of PA was studied in men, screened for abdominal aortic aneurysm (AAA) and of sub aneurysmal aorta, 25-29 mm. Prevalence of PA was high, 14.2%, and correlated with dilatation of the iliac arteries. Paper IV: Operations for ruptured PA (rPA) were identified in Swedvasc 1987-2012, medical records were reviewed. Compared with patients treated for other indications, they were 8 years older, had twice as large aneurysms (mean 64 mm) and many were treated with anticoagulants. The initial clinical picture was misleading. In conclusion, when treating PA the preferred surgical technique is OSR with a vein graft. Anatomical features of the popliteal artery and outflow vessels affect outcome. These findings are important for future surgical decision making