True aneurysms of the femoral artery require open surgical repair with aneurysmorrhaphy and interposition graft. Treatment has historically been reserved for aneurysms measuring 2.5 cm in diameter or greater [5, 6], but in a recent paper by Lawrence et al., complications of rupture, thrombosis, and embolus occurred at mean diameters of 5.7, 4.1, and 3.5 cm, respectively [2]. This included common femoral, superficial femoral, and profunda femoral artery aneurysms. This was a multicenter study and the largest to date with 236 true, degenerative femoral artery aneurysms identified in 182 patients. Based on these data, recommendations were for repair of femoral artery aneurysms of 3.5 cm or greater, with consideration to lower the threshold based on the presence of intraluminal thrombus. As noted above, duplex scan is particularly accurate for the diagnosis of intraluminal thrombus for transverse diameter measurements that will include not only the flow lumen but also thrombus lining the aneurysm sac.

The common femoral and the more rare aneurysms of the profunda femoral artery have been successfully repaired with open interposition grafts [2, 7, 8]. The aneurysms of superficial femoral arteries are also usually repaired with interposition grafts, although some superficial femoral artery aneurysms have been successfully repaired with endografts [2]. Popliteal aneurysms may be treated with aneurysmorrhaphy and interposition graft from a posterior approach, ligation, and bypass from an anteromedial approach or with an endovascular stent graft that excludes the aneurysm—with landing zones usually in the distal superficial femoral artery and distal popliteal artery where the arteries are of normal, uniform caliber. Duplex ultrasound is extremely useful in identifying the anatomy of popliteal artery aneurysms, although it is also supplemented with CT angiogram, MR angiography, or digital subtraction angiography.

B-mode imaging with and without color flow can be helpful for the identification of intraluminal thrombus . Duplex ultrasound can also be used for imaging post repair. Figures 36.5 and 36.6 show a popliteal aneurysm excluded after endovascular stent repair in longitudinal and transverse views, respectively. Note the flow within the stent graft and complete exclusion of the aneurysmal portion of the artery with thrombus in the aneurysm sac and no evidence of endoleak.

Tibial and pedal artery aneurysms can usually be treated with ligation but may require interposition graft based on the anatomy of collateral flow.

As noted above, duplex ultrasound can be used for minimally invasive treatment of pseudoaneurysms. A long, narrow “neck” makes certain pseudoaneurysms more amenable to ultrasound-guided compression or thrombin injection [9]. Figure 36.7 shows a pseudoaneurysm with a wide neck and extensive thrombus in the pseudoaneurysm sac. Figure 36.8 shows a pseudoaneurysm with a narrow neck and minimal thrombus in the sac and typical swirling flow pattern in the sac.

For ultrasound-guided compression, the duplex ultrasound is used to locate the aneurysm, and pressure is then directly applied with the transducer to stop flow in the aneurysm cavity (as identified by color Doppler) while maintaining flow in the native artery. Compression is usually held for 10–20 min, after which it is released and the pseudoaneurysm sac is reassessed for flow. If there is still flow, a second round of compression is often performed. If the pseudoaneurysm is closed, bedrest for 4–6 h is then recommended. Follow-up duplex ultrasound is again recommended in 24–48 h. This procedure is often painful for patients and may be poorly tolerated with success rates of 63–88% [10]. Ultrasound-guided thrombin injection can be a quick and much less painful alternative to compression. Local anesthetic is administered to the skin and soft tissue, and the pseudoaneurysm cavity is then punctured with a 22 or 25 gauge needle. Long spinal needles may be needed for deeper pseudoaneurysms. Identification of the needle within the aneurysm sac is critical, and after which thrombin (1000 IU/ml) is injected slowly under color Doppler guidance until there is no flow in the pseudoaneurysm cavity. Completion color Doppler is then used to confirm flow in the native artery and occlusion of the pseudoaneurysm. A success rate of 97% can be achieved with single injections with even higher rates with second injections [11]. A relative contraindication to thrombin injection is a short, wide neck, which increases the likelihood of thrombin injection into the native artery.

The most recent Cochrane review of randomized controlled trial comparing ultrasound-guided compression versus percutaneous thrombin injection concluded that percutaneous thrombin injection was more effective than a single session of ultrasound-guided compression in achieving primary pseudoaneurysm thrombosis within individual RCTs, although merged data failed to show statistical significance (RR 2.81, 95% CI 0.44 to 18.13). Conclusion was that there was evidence (albeit limited) to support the use of thrombin injection as an effective treatment for femoral pseudoaneurysm. A pragmatic approach may be to use compression (blind or ultrasound guided) as first-line treatment, reserving thrombin injection for those in whom the compression procedure fails [12]. At this time, most practitioners would use thrombin injection as a first-line treatment when available because the compression is often poorly tolerated.

Thrombin injection may not be available, or there may be contraindications to thrombin injection such as known allergy to bovine thrombin, infection, or pregnancy. In these cases, or when there are multiple pseudoaneurysm cavities, recent literature had shown safety and efficacy of the injection of saline with lidocaine into the soft tissue around the neck of pseudoaneurysm creating a tumescent effect that compresses the pseudoaneurysm neck and allows the pseudoaneurysm sac(s) to thrombose. This method may be better tolerated by patients and may require less technical skill than direct thrombin injection. However, it still requires the ability of the operator to visualize the fluid being injected into the soft tissue around the pseudoaneurysm under duplex ultrasound [13].

True aneurysms of the upper extremity are very rare. The most common involve the arch vessels, including the innominate common carotid and subclavian arteries. Proximal arch aneurysms are difficult to visualize with duplex ultrasound and are best imaged with CT angiography, MR angiography, or digital subtraction angiography. The most common type of arch vessel aneurysm is of the subclavian artery. Proximally, they may be associated with aberrant right subclavian artery. These are also difficult to visualize with duplex ultrasound.

Aneurysms of the upper extremity to distal to the clavicle are more visible with duplex ultrasound. In the distal subclavian artery, they may be associated with thoracic outlet syndrome in the form of post-stenotic dilation or degenerative aneurysms associated with repetitive trauma. They may also arise de novo—and can be associated with Marfan syndrome or radiation—particularly in the subclavian and axillary arteries [14–16]. Type IV Ehlers-Danlos syndrome has also been associated with subclavian artery aneurysms [17, 18].

In addition iatrogenic injury from inadvertent subclavian artery cannulation can result in pseudoaneurysms upon removal of these catheters because of difficulty compressing the puncture site below the clavicle. Iatrogenic injury may also cause pseudoaneurysms in more distal axillary, brachial, and radial arteries. These aneurysms can often initially be identified with duplex ultrasound.

Axillary artery aneurysms may also be caused by repetitive blunt or penetrating trauma. In particular, this may occur in athletes with repetitive motion of the arm, often involving circumflex humeral arteries or the main axillary artery. The most common presentation of this is in baseball pitchers. Similarly crutch-induced blunt trauma may cause aneurysmal dilatation of the axillary artery from repetitive blunt force. In addition, pseudoaneurysm of the axillary artery can occur after humeral fractures or anterior dislocation of the shoulder.

Aneurysms of the brachial artery are almost exclusively pseudoaneurysms related to repetitive trauma or instrumentation. Degenerative aneurysms of the brachial artery may be associated with rare connective tissue disorders such as type IV Ehlers-Danlos syndrome [19, 20].