A pseudoaneurysm is an aneurysm in which the wall is composed of fibrous tissue and does not have the three layers of the artery: intima, mesima, and epima, and is often formed by the mechanization and absorption of the hematoma formed locally after the rupture of the arterial wall. The femoral artery is used as the preferred puncture site for interventional procedures because of its superficial location, and is also a common site for vascular trauma and therefore has the highest incidence of pseudoaneurysms.
Medical injury is the most common cause of femoral artery pseudoaneurysm, and the incidence of pseudoaneurysm after femoral artery intervention varies from 0.05 to 0.5% as reported by different medical centers. In recent years, due to the increase of drug users, pseudoaneurysms due to arterial injection of drugs are also encountered clinically, and these aneurysms are often combined with infection or thrombosis. Femoral artery aneurysms caused by firearm injuries are uncommon in peacetime, and they are often combined with arteriovenous fistulas. The author also encountered a case of idiopathic infected femoral artery saccular aneurysm. Since the patient had no history of trauma and there was no pathological examination after endoluminal treatment, it was inconclusive whether it was a pseudoaneurysm, but since the clinical manifestations and treatment methods were similar to those of pseudoaneurysm, they are discussed here.
The diagnosis of pseudoaneurysm of femoral artery can be basically clear if it appears after arterial puncture or trauma. Color Doppler ultrasound has a definitive value in the diagnosis of this disease. Ultrasound examination can reveal the presence of aneurysmal cavity next to the femoral artery with blood flow signals and a channel to the femoral artery, and Doppler examination can show a typical reciprocal blood flow signal in the cavity. DSA, CTA and MRA may be used for complex cases. Pseudoaneurysm of femoral artery can lead to the following hazards if it enlarges or ruptures: rupture and bleeding of the aneurysm, dislodgement of the thrombus in the lumen leading to embolism of the distal artery, compression of the surrounding blood vessels or nerves by the aneurysm leading to dysfunction of the lower extremity, and necrosis of the skin and subcutaneous tissue due to increased local skin tension. Therefore, pseudoaneurysm should be treated actively after the diagnosis is clear.
In recent years, due to the popularization of ultrasound localization technology, the progress of pro-coagulation drugs and the development of endovascular treatment devices, the treatment methods have been gradually diversified.
Non-invasive treatment
1.Local compression therapy
This is the simplest method, in which the aneurysm is compressed directly with bare hands for at least 30 minutes. The compression should be performed so that the blood flow no longer enters the aneurysm but the femoral artery is not blocked, i.e., the ipsilateral dorsalis pedis artery pulsation should be palpable during compression. Its success requires the following conditions: the aneurysm is small, with a maximum diameter of no more than 2 cm; the patient is thin, with thin subcutaneous fat in the inguinal region, and the point of compression is relatively clear; the patient is not taking anticoagulant or antiplatelet drugs, and the aneurysm cavity is prone to thrombosis. In addition to the fact that the success rate cannot be guaranteed, this method also has some obvious disadvantages; it is physically demanding for the compressor, not easily tolerated by the patient, and not suitable for those with combined lower limb ischemia. Therefore, the use of this method should be strictly selected cases.
2.Ultrasound-guided compression
Since the 1990s, ultrasound-guided compression has become the standard method for the treatment of femoral artery pseudoaneurysms after interventional procedures, and is most widely used in clinical practice. The specific method is: first find the neck of the pseudoaneurysm under ultrasound, place the probe above the neck of the aneurysm, then compress it under ultrasound guidance until there is no blood flow through the neck of the aneurysm, while keeping the femoral artery open, generally decompress slowly for about 30 minutes, and then wrap it with an elastic bandage for 24 hours. The success rate of this method can be close to 90% for pseudoaneurysms of the femoral artery that do not exceed 3 cm in diameter and are not taking anticoagulant or antiplatelet drugs. Although the accuracy of compression is significantly better than that of freehand compression, this method is still not easy to succeed in obese patients, and it is also not suitable for patients with significant skin breakdown or infection in the groin area.
3.Apparatus compression
Instrument compression is an improvement of ultrasound-guided compression, which is also performed under ultrasound localization. After accurate positioning, a mechanical compression device is used instead of ultrasound probe or hand for continuous compression, which makes the stability and continuity of compression significantly improved, but also cannot overcome the disadvantage of local pain, which is not easily tolerated by patients.
4.Transdermal injection of saline compression
This method was reported by Gehing G from Germany. According to the author, the aneurysm was occluded by percutaneous injection of saline under the neck of the aneurysm under ultrasound guidance, and the success rate of the treatment reached 100% in 6 cases, and there was no recurrence in 4 weeks of follow-up. The author believes that saline is rapidly absorbed subcutaneously and the patient can tolerate limited tension, so this method may not be as reliable as the authors describe.
II Interventional treatment
1. Percutaneous puncture or transarterial catheter injection of procoagulant substances
For patients for whom compression therapy is ineffective or inappropriate, percutaneous puncture or transarterial catheter injection of procoagulant substances is the most common method. Commonly used procoagulant substances include adhesive bovine collagen, bioprotein gel, and thrombin. The injection methods can be direct percutaneous puncture injection under ultrasound guidance, injection through the contralateral femoral artery cannulation to the lumen of the tumor under DSA, or a combination of the two for patients with wide tumor necks, i.e., first cannulation through the contralateral femoral artery and closure of the tumor neck using a balloon, followed by percutaneous puncture injection under ultrasound guidance. The most commonly used ultrasound-guided thrombin injection method is described here as an example: first, ultrasound examination is performed to determine the location of the arterial incision, the diameter and length of the aneurysm neck, and the size and number of the aneurysm cavity; the drug is usually bovine thrombin at a concentration of 200 u/ml; the thrombin syringe, saline syringe, and puncture needle are connected with a tee; the aneurysm cavity is punctured percutaneously with an 18G puncture needle under ultrasound guidance. Directly puncture the tumor cavity, keeping the needle tip away from the tumor neck, inject saline under ultrasound surveillance to determine the site of the puncture needle again, and then slowly inject thrombin until the colored blood flow signal in the tumor cavity disappears; stay in bed for 6 hours after the operation, pay attention to observe the distal arterial pulsation to prevent the thrombus from expanding or dislodging to embolize the distal artery.
2.spring ring embolization
Spring coil embolization can be used for patients for whom the above treatment methods are ineffective or contraindicated. The simpler operation is to directly puncture the aneurysm with an 18G puncture needle under DSA, image the diameter of the aneurysm neck, and then choose the largest possible spring coil, at least 2mm in diameter, to be introduced into the aneurysm through the puncture needle, and try to completely fill the aneurysm. If the patient has a local skin infection on the surface of the aneurysm, the catheter can be superselected into the aneurysm using a contralateral femoral artery puncture to fill the spring coil. This method has a high immediate success rate, but is prone to recurrence if the filling is incomplete.
3.Intraluminal isolation
Intraluminal isolation of femoral artery pseudoaneurysm means closing the rupture of femoral artery with a membrane stent in the femoral artery, so that the blood in the lumen of the aneurysm no longer communicates with the blood in the artery, thus forming a thrombus and occluding the aneurysm. The appropriate indications for this approach are patients with large aneurysms, wide necks, or combined arteriovenous fistulas. There are two main types of devices available: woven or laser-etched stents with a coating, such as Wallfraft (Bostion) and Fluency (Bard), and extensions of the iliac artery for intraluminal isolation of abdominal aortic aneurysms by suturing ultra-thin artificial vessels to Z-shaped stents, such as Talent (Medtronic) and Zenith (Cook). Zenith (Cook Inc.), etc. The former has better flexibility, long conveyors, and the diameter of the conveyors is around 10F, which can be introduced by optional transversal femoral artery puncture. The procedure needs to be performed under DSA, and the stent is released to cover the rupture of the femoral artery after contrast positioning, and if the rupture is close to the bifurcation of the femoral artery, the distal end of the stent can be fixed to the superficial femoral artery to close the deep femoral artery together, and the deep femoral artery often has good collateral compensation, and the postoperative period will not show femoral Ischemic symptoms do not occur in the femur after surgery. The latter type of stent deliverer is short, poorly pliable, and the diameter of the deliverer is 12~14F. It is usually necessary to dissect out the introducing artery, puncture it under direct vision, and then suture the puncture point after withdrawing the deliverer, so it is generally not preferred. However, this type of stent is more supportive, has thicker vessels than the former, and has a better effect of isolating blood flow than the former. The author’s experience is to dissect a segment of the superficial femoral artery at the lower end of the femoral triangle in front of the collecting duct, which is usually 5-6 mm in diameter and is sufficient to serve as the introducing artery, and the operating distance is short and the operation is convenient.
Surgical procedures
1.Aneurysm reconstruction
Atherectomy reconstruction is the most traditional method for treating femoral artery pseudoaneurysm and is currently used mainly for patients who are not suitable or unwilling to undergo minimally invasive treatment. The first is the timing of surgery, which should be performed at least 3 months after the formation of the pseudoaneurysm, when the pseudoenvelope is formed around the aneurysm and the adhesion between the aneurysm wall and the surrounding tissues is reduced, making dissection easier; the second is the control of the proximal femoral artery, which must be controlled before opening the aneurysm. Thirdly, it is not necessary to completely resect the aneurysm, but to open the aneurysm directly from the anterior wall of the aneurysm after controlling the proximal femoral artery and repair the femoral artery rupture with sutures in the aneurysm cavity, while the bleeding from the distal end can be controlled by local compression only; fourthly, excessive dissection should be avoided and all layers of tissues should be carefully sutured when closing the incision to avoid the occurrence of lymphatic leakage.
2.Femoral artery ligation
Femoral artery ligation is not a routine treatment for femoral artery pseudoaneurysm, but a life-saving method in critical situations, mainly for the treatment of infected femoral artery aneurysm rupture. This condition is most commonly seen in aneurysms caused by drug injection via the femoral artery. The procedure involves first controlling the proximal femoral or external iliac artery, then directly opening the aneurysm and suturing the regurgitated distal femoral artery within the aneurysm cavity. In severe infections, the local wound is left open after removal of the aneurysm and thrombus, and the wound is changed until clean and then treated in the second stage. For the blood supply of the lower extremity, there are two kinds of countermeasures depending on the specific situation of the patient: in some patients, due to the compression of the aneurysm, the femoral artery has been severely stenosed and the lower extremity has abundant collateral branches, so in these cases, the bleeding pressure of the distal regurgitation is high and the affected extremity will not be severely ischemic after ligation of the femoral artery, so reconstruction may not be considered; in other patients, the lower extremity lacks sufficient collateral circulation and arterial reconstruction of the lower extremity should be considered. A more appropriate method is to choose a ringed PTFE artificial vessel and perform an extra-anatomical bypass from the ipsilateral iliac artery to the superficial femoral artery through a closed hole.