Ultrasound-guided thrombin injection for the treatment of iatrogenic pseudoaneurysm of the femoral artery.

Background: Pseudoaneurysm occurring after catheterization of the femoral artery is associated with significant morbidity. Percutaneous ultrasound-guided thrombin injection has recently emerged as a potential first-line therapy. Objectives: To evaluate the efficacy of this treatment in eight patients with iatrogenic femoral artery pseudoaneurysm. Methods: After attempted treatment with external compression had failed, eight patients with iatrogenic femoral artery pseudoaneurysm were treated with thrombin injection. Treatment performed between 2 and 9 days following arterial puncture. The study group comprised seven males and one female ranging in age from 23 to 89 years (median 70). Seven had undergone cardiac catheterization with or without intervention, and five were receiving antiplatelet and/or anticoagulant drugs. Arterial pseudoaneurysm resulted from femoral vein catheterization in one patient. Using a sterile technique and real-time Doppler ultrasound guidance, a dilute solution of bovine thrombin (average dose 250 units, range 100±600), was slowly injected directly into the pseudoaneurysm until cessation of flow was seen. Patients were allowed to walk within 2 hours of the procedure and were followed up clinically and by color Doppler ultrasound during the admission. Results: Cardiac catheterization had been inadvertently performed via the superficial or profunda femoris arteries in four of the eight patients. Thrombin injection was initially successful in all eight patients without complication. Thrombosis occurred immediately in every case. Early recanalization of pseudoaneurysm occurred in one patient despite repeat thrombin injection and attempted ultrasound-guided compression. He eventually required surgical repair. The final success rate was 87.5% (7/8). Conclusion: Faulty puncture technique is an important risk factor for the development of post-catheterization femoral artery pseudoaneurysm. Ultrasound-guided thrombin injection is a safe, rapid, well-tolerated, inexpensive and successful therapy. If initial external compression with a sandbag fails to result in thrombosis of the pseudoaneurysm then thrombin injection should be considered as first-line therapy. If unsuccessful, it does not preclude the use of alternative treatment modalities. Further study is necessary to assess the long-term effects of thrombin injection. IMAJ 2001;3:649±652 The incidence of iatrogenic pseudoaneurysm following catheterization of the femoral artery is reported to be 7±8% in patients undergoing diagnostic and therapeutic angiography [1]. Antegrade puncture, anticoagulation, large introducer sheaths, faulty puncture technique and inadequate compression are some of the known risk factors for the development of pseudoaneurysm. Accepted treatment includes non-directed compression with sandbags or external compression devices, ultrasound-guided compression, catheter embolization and surgical repair. Surgery is indicated when there is evidence of rapid expansion of the pseudoaneurysm (threatened rupture), limb ischemia or distal emboli, extensive soft tissue damage, infection, or if other techniques have failed. Ultrasound-guided compression is successful in achieving thrombosis of the pseudoaneurysm, without the need for operative intervention, in 62±95% of cases [1±3]. In recent years it has become the procedure of choice for most patients. By directly compressing the neck of the pseudoaneurysm, ultrasound-guided compression results in occlusion of blood flow in the pseudoaneurysm cavity. Thrombosis of the contents occurs due to the natural coagulation cascade. It is a painful and time-consuming procedure that may require several attempts before succeeding [2]. It is least likely to succeed in anticoagulated patients, or when the pseudoaneurysm neck is wide or not directly accessible for compression. Recently, several reports have suggested that ultrasoundguided thrombin injection is a safe, effective and rapid therapy for the treatment of pseudoaneurysm, without the limitations of ultrasound-guided compression [4±8]. We report here our initial results using this technique. Materials and Methods Between February and July 2000, eight patients with iatrogenic femoral artery pseudoaneurysm were referred for thrombin injection. Four had undergone cardiac catheterization at this institution. One was referred from the intensive care unit following insertion of a femoral vein dialysis catheter. Three were referred from other hospitals after cardiac catheterization. The patients included seven males and one female with an age range of 23±89 years (median 70 years). Attempted external compression using either sandbags or compression devices had failed in seven. Table 1 summarizes the patients' data. Approval from the local institutional review board (Helsinki) was obtained (due to the ` off-label'' usage of the drug) and Original Articles 649 IMAJ . Vol 3 . September 2001 Thrombin Injection of Femoral Artery Pseudoaneurysm patients gave informed consent for the procedure. Exclusion criteria for thrombin injection included all indications for surgical repair or known hypersensitivity to thrombin. Initially, the diagnosis was confirmed by clinical and color Doppler ultrasound examination [Figure 1]. The precise location, origin and dimensions of the pseudoaneurysm were documented prior to thrombin Injection [Table 1]. Ankle brachial indices were measured bilaterally. The procedure was performed with a sterile technique. A 20 gauge co-axial needle was inserted into the cavity of the pseudoaneurysm using real-time sonographic guidance with a `freehand' technique. The needle tip was directed away from the neck of the pseudoaneurysm. Thrombin solution (Bovine, Topical Thrombin, USP, Jones Pharma Inc, USA), diluted to 200 units/ml, was then slowly injected until color Doppler flow within the pseudoaneurysm cavity ceased [Figure 2]. Repeat color Doppler ultrasound evaluation of the nearby femoral vessels was performed to confirm patency. Ipsilateral peripheral limb pulses were evaluated before and immediately after thrombin injection. Patients were allowed to get out of bed 2 hours following the procedure. Repeat clinical and sonographic evaluation was performed prior to discharge from hospital, together with measurement of ankle brachial indices.