Popliteal artery aneurysms (PAA) are local enlargements of the popliteal artery to more than 12 mm and at least 1.5 times the artery diameter of the proximal segment [1]. In PAA with a diameter of 20–30 mm, the mean annual growth rate is 3 mm, while for diameters of more than 30 mm it is 3.7 mm [2].
The popliteal artery is the most common location of peripheral artery aneurysms, but PAA is still rather uncommon. Its prevalence in men over the age of 65 is 1% [3]. PAA in women is extremely rare; almost all patients reported in the literature are male [4]. PAA prevalence increases significantly in patients with aortic aneurysms [5]. A publication from 2016 reports a PAA prevalence of 19% in patients with abdominal aortic aneurysm (AAA) [6]. In patients with bilateral PAA, the prevalence of AAA is 69% [3].
About 80% of PAA remain asymptomatic until diagnosis [7], but about 14% of clinically silent PAA become symptomatic each year [8]. The symptoms correspond to those in peripheral arterial occlusive disease with stenoses and occlusions; intermittent claudication; microemboli; pain at rest; and trophic disorders. PAA may also be the cause of acute leg ischemia, resulting in major amputation in up to 40% of cases [9].
The outcome after treatment of symptomatic PAA is usually significantly worse than after elective management. The American Heart Association therefore recommends early elective treatment of asymptomatic PAA of more than 2 cm in diameter to reduce the risk of thromboembolic complications and limb loss [10].
In 1912, Erich Lexer performed the first PAA revascularization with vein graft via posterior access. In 1969, W.S. Edwards ligated the PAA both proximally and distally and bypassed the aneurysm with an autogenous greater saphenous vein graft, which is still considered the therapeutic standard today [11, 12].
Endovascular treatment of PAA was first proposed in 1994, but due to the rarity of the disease and the lack of large, randomized trials, there are still no evidence level A recommendations for the choice of therapeutic procedure.
The Swedish Vascular Registry (Swedvasc) retrospectively analyzed 717 PAA cases with a mean follow-up of 7.2 years. After one year the primary patency rates were: posterior access—vein 85%, alloplastic vascular graft 81 %; medial access—vein 90 %, alloplastic vascular graft 72%. The amputation rate within one year was 8.8%. A further 17 amputations had to be performed over the long term, so that the total amputation rate registered was 11%. The long-term risk of amputation was twice as high with alloplastic vascular grafts versus autogenous vein grafts and about two and a half times higher during emergent procedures for acute ischemia than for elective surgery. The risk of aneurysm expansion after PAA treatment via medial access was significantly higher than in treatment via posterior access (33% vs. 8.3%) [13]. Other trials also concluded that posterior access is superior in terms of primary and secondary patency rates and reintervention-free survival, and that autogenous vein material is preferred whenever possible [14-20].