8.1 

Popliteal Artery Aneurysm

Poplitealarteryaneurysmsarethemostcommonperipheralarteryaneurysm.Thepopliteal artery is considered aneurysmal at a diameter of 1.5 cm and complications usually occur once the aneurysm grows to 2 cm or greater. Atherosclerosis is the primary underlying pathology in the formation of most popliteal artery aneurysms and they affect a predictable population, occurring most often in men in their 60s and 70s.1–4 The presence of a popliteal artery aneurysm increases the risk for other aneurysms; 36–54% are bilateral and 25–54% occur synchronously with infrarenal abdominal aortic aneuryms.1–6 [Q1: D] Diagnosis of apoplitealarteryaneurysmissuspectedwiththedetectionofaprominentpulseorpulsatile­

mass in the popliteal fossa on physical exam. This is confirmed with duplex ultrasonography which can differentiate the aneurysmal segment from other masses in the popliteal fossa and demonstrate mural thrombus. [Q2: C] Angiography can be an important adjunctive exam to determine distal run-off in preparation for surgical repair. Although a significant percentage of these aneurysms are diagnosed incidentally, the majority (58–71%) of popliteal artery aneurysms are symptomatic at the time of diagnosis.1,3,5,7 Most common presentations are distal embolization or acute thrombosis, followed by compressive symptoms.6 Compression of adjacent structures of the popliteal fossa can cause venous obstruction (deep venous thrombosis) and pain (compression of adjacent nerves). Rupture can occur rarely, in less than 5% of the presentations.1,6 [Q3: A, B, C, D] Distal embolization can cause minor or major tissue loss but more importantly, it destroys distal run-off, decreasing patency of operative repair.

Indications for repair include size of 2 cm and greater, the presence of significant mural thrombus, compression of adjacent structures causing pain and/or venous obstruction and symptoms of embolization. Elective repair in asymptomatic patients results in excellent graft patency and limb preservation. Conversely, repair in symptomatic patients has decreased graft patency and limb salvage rates, particularly in emergent repair for acute thrombosis and rarely rupture.1,2,7,8 [Q4: B] Therefore, popliteal aneurysms are better repaired in the asymptomatic state once they reach 2 cm, or when associated with significant thrombus. Options for repair include open bypass with ligation using a medial approach, open aneurysmorrhaphy via a posterior approach or endovascular stent grafting. Open repair is the gold standard in the treatment of popliteal artery aneurysm. The medial approach is most often utilized as it offers the best exposure of the distal superficial femoral artery, the trifurcation and the greater saphenous vein. The posterior approach is sometimes preferred in cases with limited extent of the disease especially when ligation of all branches of the aneurysm is necessary to relieve compressive symptoms. Endovascular repair of a popliteal artery aneurysm is a minimally invasive approach that has gained acceptance recently with the addition of kink resistant stent grafts. It is a good alternative to open repair in patients with suitable anatomy especially poor operative candidates. A good runoff and suitable landing zones are important determinants of success. Small studies have shown excellent results with endovascular repair with similar patency at

intermediate follow-up and faster/shorter recovery.8 Contraindications to endovascular stent grafting for popliteal artery aneurysms include compressive symptoms and singlevessel run-off. An acutely thrombosed popliteal artery aneurysm often presents as an acutely ischemic limb and requires emergent therapy. Systemic anti-coagulation should be initiated immediately and directed thrombolytics improve distal run-off in preparation for surgical repair. [Q5: A, B, C]

References

1.Lichtenfels E, Frankini AD, Bonamigo TP, et al. Popliteal artery aneurysm surgery: the role of emergency setting. Vasc Endovasc Surg. 2008;42(2):159-164.

2.Ravn H, Wanhainen A, Bjorck M. Surgical technique and long-term results after popliteal artery aneurysm repair: results from 717 legs. J Vasc Surg. 2007;46(2):236-243.

3.Martelli E, Ippoliti A, Ventoruzzo G, et al. Popliteal artery aneurysms. Factors associated with thromboembolism and graft failure. Int Angiol. 2004;23(1):54-65.

4.Huang Y, Gloviczki P, Noel AA, et al. Early complications and long-term outcome after open surgical treatment of popliteal artery aneurysms: is exclusion with saphenous vein bypass still the gold standard? J Vasc Surg. 2007;45(4):706-713. discussion 713-115.

5.Ascher E, Markevich N, Schutzer RW, et al. Small popliteal artery aneurysms: are they clinically significant? J Vasc Surg. 2003;37(4):755-760.

6.Ravn H, Bergqvist D, Bjorck M. Nationwide study of the outcome of popliteal artery aneurysms treated surgically. Br J Surg. 2007;94(8):970-977.

7.Pulli R, Dorigo W, Troisi N, et al. Surgical management of popliteal artery aneurysms: which factors affect outcomes? J Vasc Surg. 2006;43(3):481-487.

8.Antonello M, Frigatti P, Battocchio P, et al. Open repair versus endovascular treatment for asymptomatic popliteal artery aneurysm: results of a prospective randomized study. J Vasc Surg. 2005;42(2):185-193.