Treatment of Iatrogenic Femoral Arterial Pseudoaneurysms
Abstract & Commentary
Synopsis: The results of this study suggest that initial therapy for iatrogenic femoral arterial pseudoaneurysms should consist of using ultrasound-guided percutaneous injection of thrombin into the pseudo-aneurysm, as opposed to using ultrasound guided compression repair.
Source: Paulson EK, et al. Treatment of iatrogenic femoral arterial pseudoaneurysms: Comparison of US-guided
thrombin injection with compression repair. Radiology 2000; 215:403-408.
Until 1991, iatrogenic femoral arterial pseudoaneurysms were repaired by surgical ligation. Since 1991, the preferred initial approach to terminate blood flow in these aneurysms has been to use a technique known as "ultrasound (US) guided compression." In 1998, however, a new alternative approach was described that used US-guided percutaneous injection of thrombin into the pseudoaneurysm.1 Upon learning of this alternative method, Paulson and colleagues began to apply this new technique, and in this publication, Paulson et al report their results of a comparison study to evaluate success rates, procedure times, and complication rates between these two different US-guided techniques.
To do this analysis, a retrospective study was done of 26 patients with iatrogenic femoral arterial pseudo-aneurysms who were treated with US-guided thrombin injection vs. 281 consecutively treated patients who underwent US-guided compression repair. Patient demographics, clinical variables, and pseudoaneurysm characteristics were similar for the two groups with the exception that the thrombin-treated group had more patients who were anticoagulated and more patients who underwent angioplasty. In addition, the pseudo-aneurysms in this group were slightly smaller and had a somewhat narrower neck width.
The thrombin injection technique consists of using a 5-7.5 MHz linear or curved array transducer with an attached needle guide to direct placement of a 22-gauge spinal needle into the flow lumen of a pseudoaneurysm. Optimal needle placement is crucial as it is important to position the needle tip where blood flow is directed away from the pseudoaneurysm neck. To maximize visualization of the needle tip, color Doppler is turned off as the needle is advanced into the pseudoaneurysm. Once a satisfactory needle position is achieved, color Doppler is restored to the image, and 0.1-0.3 (100-300 U) of thrombin is injected during a 3-5 second period. In this study, continuous US monitoring during the procedure revealed that in 20 of 26, patients complete thrombosis was achieved in six seconds (range, 3-20 s). In five of the remaining patients, advancing the needle and administering additional thrombus was all that was required to obliterate pseudoaneurysm flow. In the final patient, a satisfactory result was achieved after thrombin was injected via a second puncture. The results of this method, therefore, were considered successful in 25 of 26 patients (96%). In no patient was conscious sedation used, and in only three cases was local lidocaine administered to anesthetize the skin.
The US-guided compression technique consists of applying manual transducer compression to the neck of the pseudoaneurysm for 10-20 minute time intervals.
If, upon release of transducer compression, flow continues into the pseudoaneurysm, the cycle is repeated until patient or operator fatigue compels termination of the procedure. In their study, this method of treatment required an average time of 41.5 minutes and was effective in 203 of 281 patients (74%). Conscious sedation was administered routinely to each patient.
Comment by Faye C. Laing, MD
It is gratifying to read the results of this study for several important reasons. From the point of view of a sonologist, US-guided compression of a pseudo-aneurysm typically occupies the examination room for between one and two hours. Not only is this method physically exhausting to both patient and physician, but it can wreck havoc to an already overtaxed US schedule. From the point of view of a patient, US-guided compression requires sedation, and this approach is successful only three-quarters of the time. In contrast, US-guided percutaneous injection of thrombin into a pseudoaneurysm is much more rapid, safe, painless, and if done appropriately, is successful in virtually all cases.
Also, as pointed out by Paulson et al, another advantage of thrombin injection is that it can be used for pseudoaneurysms located above the inguinal ligament. When a pseudoaneurysm is at this level, it should not be compressed because of the potential for intra or extraperitoneal rupture. Another distinct advantage of thrombin injection is that it is successful in patients receiving systemic heparin. Although their numbers were limited, thrombin injection was successful for each of nine patients receiving heparin. In contrast, of the 14 heparinized patients treated by compression, only five (36%) pseudoaneurysms thrombosed.
To achieve results similar to those reported by Paulson et al, it is important to adhere to the technical aspects that they emphasized. Because thrombus begins to form within 2-5 seconds following thrombin injection, precise delineation of the anatomy and careful needle placement within the flow lumen of the pseudo-aneurysm is mandatory. The goal is to inject thrombin so that it flows into the pseudoaneurysm and away from the neck. This approach will obviate the theoretical risks of thrombosing either the femoral artery or causing subsequent embolic phenomena. Because only a small amount of thrombin is injected, Paulson et al recommend using a 1 mL syringe to better control delivery of this extremely potent thrombogenic agent. It is also critical to use color Doppler to carefully monitor thrombus formation during the injection.
Despite the relatively small number of cases reported by Paulson et al, and the relatively few articles that address US-guided thrombin injection for treatment of iatrogenic femoral arterial pseudoaneurysms, the results of this and other studies are very gratifying and suggest that thrombin injection should replace compression repair for initial therapy of iatrogenic femoral artery pseudoaneurysms.
Reference
1. Kang SS, et al. Percutaneous ultrasound guided thrombin injection: A new method for treating postcatheterization femorpseudoaneurysms. J Vasc Sur 1998;27:1032-1038.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content